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  • Stored Procedures with SSRS? Hmm… not so much

    - by Rob Farley
    Little Bobby Tables’ mother says you should always sanitise your data input. Except that I think she’s wrong. The SQL Injection aspect is for another post, where I’ll show you why I think SQL Injection is the same kind of attack as many other attacks, such as the old buffer overflow, but here I want to have a bit of a whinge about the way that some people sanitise data input, and even have a whinge about people who insist on using stored procedures for SSRS reports. Let me say that again, in case you missed it the first time: I want to have a whinge about people who insist on using stored procedures for SSRS reports. Let’s look at the data input sanitisation aspect – except that I’m going to call it ‘parameter validation’. I’m talking about code that looks like this: create procedure dbo.GetMonthSummaryPerSalesPerson(@eomdate datetime) as begin     /* First check that @eomdate is a valid date */     if isdate(@eomdate) != 1     begin         select 'Please enter a valid date' as ErrorMessage;         return;     end     /* Then check that time has passed since @eomdate */     if datediff(day,@eomdate,sysdatetime()) < 5     begin         select 'Sorry - EOM is not complete yet' as ErrorMessage;         return;     end         /* If those checks have succeeded, return the data */     select SalesPersonID, count(*) as NumSales, sum(TotalDue) as TotalSales     from Sales.SalesOrderHeader     where OrderDate >= dateadd(month,-1,@eomdate)         and OrderDate < @eomdate     group by SalesPersonID     order by SalesPersonID; end Notice that the code checks that a date has been entered. Seriously??!! This must only be to check for NULL values being passed in, because anything else would have to be a valid datetime to avoid an error. The other check is maybe fair enough, but I still don’t like it. The two problems I have with this stored procedure are the result sets and the small fact that the stored procedure even exists in the first place. But let’s consider the first one of these problems for starters. I’ll get to the second one in a moment. If you read Jes Borland (@grrl_geek)’s recent post about returning multiple result sets in Reporting Services, you’ll be aware that Reporting Services doesn’t support multiple results sets from a single query. And when it says ‘single query’, it includes ‘stored procedure call’. It’ll only handle the first result set that comes back. But that’s okay – we have RETURN statements, so our stored procedure will only ever return a single result set.  Sometimes that result set might contain a single field called ErrorMessage, but it’s still only one result set. Except that it’s not okay, because Reporting Services needs to know what fields to expect. Your report needs to hook into your fields, so SSRS needs to have a way to get that information. For stored procs, it uses an option called FMTONLY. When Reporting Services tries to figure out what fields are going to be returned by a query (or stored procedure call), it doesn’t want to have to run the whole thing. That could take ages. (Maybe it’s seen some of the stored procedures I’ve had to deal with over the years!) So it turns on FMTONLY before it makes the call (and turns it off again afterwards). FMTONLY is designed to be able to figure out the shape of the output, without actually running the contents. It’s very useful, you might think. set fmtonly on exec dbo.GetMonthSummaryPerSalesPerson '20030401'; set fmtonly off Without the FMTONLY lines, this stored procedure returns a result set that has three columns and fourteen rows. But with FMTONLY turned on, those rows don’t come back. But what I do get back hurts Reporting Services. It doesn’t run the stored procedure at all. It just looks for anything that could be returned and pushes out a result set in that shape. Despite the fact that I’ve made sure that the logic will only ever return a single result set, the FMTONLY option kills me by returning three of them. It would have been much better to push these checks down into the query itself. alter procedure dbo.GetMonthSummaryPerSalesPerson(@eomdate datetime) as begin     select SalesPersonID, count(*) as NumSales, sum(TotalDue) as TotalSales     from Sales.SalesOrderHeader     where     /* Make sure that @eomdate is valid */         isdate(@eomdate) = 1     /* And that it's sufficiently past */     and datediff(day,@eomdate,sysdatetime()) >= 5     /* And now use it in the filter as appropriate */     and OrderDate >= dateadd(month,-1,@eomdate)     and OrderDate < @eomdate     group by SalesPersonID     order by SalesPersonID; end Now if we run it with FMTONLY turned on, we get the single result set back. But let’s consider the execution plan when we pass in an invalid date. First let’s look at one that returns data. I’ve got a semi-useful index in place on OrderDate, which includes the SalesPersonID and TotalDue fields. It does the job, despite a hefty Sort operation. …compared to one that uses a future date: You might notice that the estimated costs are similar – the Index Seek is still 28%, the Sort is still 71%. But the size of that arrow coming out of the Index Seek is a whole bunch smaller. The coolest thing here is what’s going on with that Index Seek. Let’s look at some of the properties of it. Glance down it with me… Estimated CPU cost of 0.0005728, 387 estimated rows, estimated subtree cost of 0.0044385, ForceSeek false, Number of Executions 0. That’s right – it doesn’t run. So much for reading plans right-to-left... The key is the Filter on the left of it. It has a Startup Expression Predicate in it, which means that it doesn’t call anything further down the plan (to the right) if the predicate evaluates to false. Using this method, we can make sure that our stored procedure contains a single query, and therefore avoid any problems with multiple result sets. If we wanted, we could always use UNION ALL to make sure that we can return an appropriate error message. alter procedure dbo.GetMonthSummaryPerSalesPerson(@eomdate datetime) as begin     select SalesPersonID, count(*) as NumSales, sum(TotalDue) as TotalSales, /*Placeholder: */ '' as ErrorMessage     from Sales.SalesOrderHeader     where     /* Make sure that @eomdate is valid */         isdate(@eomdate) = 1     /* And that it's sufficiently past */     and datediff(day,@eomdate,sysdatetime()) >= 5     /* And now use it in the filter as appropriate */     and OrderDate >= dateadd(month,-1,@eomdate)     and OrderDate < @eomdate     group by SalesPersonID     /* Now include the error messages */     union all     select 0, 0, 0, 'Please enter a valid date' as ErrorMessage     where isdate(@eomdate) != 1     union all     select 0, 0, 0, 'Sorry - EOM is not complete yet' as ErrorMessage     where datediff(day,@eomdate,sysdatetime()) < 5     order by SalesPersonID; end But still I don’t like it, because it’s now a stored procedure with a single query. And I don’t like stored procedures that should be functions. That’s right – I think this should be a function, and SSRS should call the function. And I apologise to those of you who are now planning a bonfire for me. Guy Fawkes’ night has already passed this year, so I think you miss out. (And I’m not going to remind you about when the PASS Summit is in 2012.) create function dbo.GetMonthSummaryPerSalesPerson(@eomdate datetime) returns table as return (     select SalesPersonID, count(*) as NumSales, sum(TotalDue) as TotalSales, '' as ErrorMessage     from Sales.SalesOrderHeader     where     /* Make sure that @eomdate is valid */         isdate(@eomdate) = 1     /* And that it's sufficiently past */     and datediff(day,@eomdate,sysdatetime()) >= 5     /* And now use it in the filter as appropriate */     and OrderDate >= dateadd(month,-1,@eomdate)     and OrderDate < @eomdate     group by SalesPersonID     union all     select 0, 0, 0, 'Please enter a valid date' as ErrorMessage     where isdate(@eomdate) != 1     union all     select 0, 0, 0, 'Sorry - EOM is not complete yet' as ErrorMessage     where datediff(day,@eomdate,sysdatetime()) < 5 ); We’ve had to lose the ORDER BY – but that’s fine, as that’s a client thing anyway. We can have our reports leverage this stored query still, but we’re recognising that it’s a query, not a procedure. A procedure is designed to DO stuff, not just return data. We even get entries in sys.columns that confirm what the shape of the result set actually is, which makes sense, because a table-valued function is the right mechanism to return data. And we get so much more flexibility with this. If you haven’t seen the simplification stuff that I’ve preached on before, jump over to http://bit.ly/SimpleRob and watch the video of when I broke a microphone and nearly fell off the stage in Wales. You’ll see the impact of being able to have a simplifiable query. You can also read the procedural functions post I wrote recently, if you didn’t follow the link from a few paragraphs ago. So if we want the list of SalesPeople that made any kind of sales in a given month, we can do something like: select SalesPersonID from dbo.GetMonthSummaryPerSalesPerson(@eomonth) order by SalesPersonID; This doesn’t need to look up the TotalDue field, which makes a simpler plan. select * from dbo.GetMonthSummaryPerSalesPerson(@eomonth) where SalesPersonID is not null order by SalesPersonID; This one can avoid having to do the work on the rows that don’t have a SalesPersonID value, pushing the predicate into the Index Seek rather than filtering the results that come back to the report. If we had joins involved, we might see some of those being simplified out. We also get the ability to include query hints in individual reports. We shift from having a single-use stored procedure to having a reusable stored query – and isn’t that one of the main points of modularisation? Stored procedures in Reporting Services are just a bit limited for my liking. They’re useful in plenty of ways, but if you insist on using stored procedures all the time rather that queries that use functions – that’s rubbish. @rob_farley

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  • Looking into Enum Support in Entity Framework 5.0 Code First

    - by nikolaosk
    In this post I will show you with a hands-on demo the enum support that is available in Visual Studio 2012, .Net Framework 4.5 and Entity Framework 5.0. You can have a look at this post to learn about the support of multilple diagrams per model that exists in Entity Framework 5.0. We will demonstrate this with a step by step example. I will use Visual Studio 2012 Ultimate. You can also use Visual Studio 2012 Express Edition. Before I move on to the actual demo I must say that in EF 5.0 an enumeration can have the following types. Byte Int16 Int32 Int64 Sbyte Obviously I cannot go into much detail on what EF is and what it does. I will give again a short introduction.The .Net framework provides support for Object Relational Mapping through EF. So EF is a an ORM tool and it is now the main data access technology that microsoft works on. I use it quite extensively in my projects. Through EF we have many things out of the box provided for us. We have the automatic generation of SQL code.It maps relational data to strongly types objects.All the changes made to the objects in the memory are persisted in a transactional way back to the data store. You can find in this post an example on how to use the Entity Framework to retrieve data from an SQL Server Database using the "Database/Schema First" approach. In this approach we make all the changes at the database level and then we update the model with those changes. In this post you can see an example on how to use the "Model First" approach when working with ASP.Net and the Entity Framework. This model was firstly introduced in EF version 4.0 and we could start with a blank model and then create a database from that model.When we made changes to the model , we could recreate the database from the new model. You can search in my blog, because I have posted many posts regarding ASP.Net and EF. I assume you have a working knowledge of C# and know a few things about EF. The Code First approach is the more code-centric than the other two. Basically we write POCO classes and then we persist to a database using something called DBContext. Code First relies on DbContext. We create 2,3 classes (e.g Person,Product) with properties and then these classes interact with the DbContext class. We can create a new database based upon our POCOS classes and have tables generated from those classes.We do not have an .edmx file in this approach.By using this approach we can write much easier unit tests. DbContext is a new context class and is smaller,lightweight wrapper for the main context class which is ObjectContext (Schema First and Model First). Let's begin building our sample application. 1) Launch Visual Studio. Create an ASP.Net Empty Web application. Choose an appropriate name for your application. 2) Add a web form, default.aspx page to the application. 3) Now we need to make sure the Entity Framework is included in our project. Go to Solution Explorer, right-click on the project name.Then select Manage NuGet Packages...In the Manage NuGet Packages dialog, select the Online tab and choose the EntityFramework package.Finally click Install. Have a look at the picture below   4) Create a new folder. Name it CodeFirst . 5) Add a new item in your application, a class file. Name it Footballer.cs. This is going to be a simple POCO class.Place it in the CodeFirst folder. The code follows public class Footballer { public int FootballerID { get; set; } public string FirstName { get; set; } public string LastName { get; set; } public double Weight { get; set; } public double Height { get; set; } public DateTime JoinedTheClub { get; set; } public int Age { get; set; } public List<Training> Trainings { get; set; } public FootballPositions Positions { get; set; } }    Now I am going to define my enum values in the same class file, Footballer.cs    public enum FootballPositions    {        Defender,        Midfielder,        Striker    } 6) Now we need to create the Training class. Add a new class to your application and place it in the CodeFirst folder.The code for the class follows.     public class Training     {         public int TrainingID { get; set; }         public int TrainingDuration { get; set; }         public string TrainingLocation { get; set; }     }   7) Then we need to create a context class that inherits from DbContext.Add a new class to the CodeFirst folder.Name it FootballerDBContext.Now that we have the entity classes created, we must let the model know.I will have to use the DbSet<T> property.The code for this class follows       public class FootballerDBContext:DbContext     {         public DbSet<Footballer> Footballers { get; set; }         public DbSet<Training> Trainings { get; set; }     } Do not forget to add  (using System.Data.Entity;) in the beginning of the class file 8) We must take care of the connection string. It is very easy to create one in the web.config.It does not matter that we do not have a database yet.When we run the DbContext and query against it,it will use a connection string in the web.config and will create the database based on the classes. In my case the connection string inside the web.config, looks like this      <connectionStrings>    <add name="CodeFirstDBContext"  connectionString="server=.\SqlExpress;integrated security=true;"  providerName="System.Data.SqlClient"/>                       </connectionStrings>   9) Now it is time to create Linq to Entities queries to retrieve data from the database . Add a new class to your application in the CodeFirst folder.Name the file DALfootballer.cs We will create a simple public method to retrieve the footballers. The code for the class follows public class DALfootballer     {         FootballerDBContext ctx = new FootballerDBContext();         public List<Footballer> GetFootballers()         {             var query = from player in ctx.Footballers where player.FirstName=="Jamie" select player;             return query.ToList();         }     }   10) Place a GridView control on the Default.aspx page and leave the default name.Add an ObjectDataSource control on the Default.aspx page and leave the default name. Set the DatasourceID property of the GridView control to the ID of the ObjectDataSource control.(DataSourceID="ObjectDataSource1" ). Let's configure the ObjectDataSource control. Click on the smart tag item of the ObjectDataSource control and select Configure Data Source. In the Wizzard that pops up select the DALFootballer class and then in the next step choose the GetFootballers() method.Click Finish to complete the steps of the wizzard. Build your application.  11)  Let's create an Insert method in order to insert data into the tables. I will create an Insert() method and for simplicity reasons I will place it in the Default.aspx.cs file. private void Insert()        {            var footballers = new List<Footballer>            {                new Footballer {                                 FirstName = "Steven",LastName="Gerrard", Height=1.85, Weight=85,Age=32, JoinedTheClub=DateTime.Parse("12/12/1999"),Positions=FootballPositions.Midfielder,                Trainings = new List<Training>                             {                                     new Training {TrainingDuration = 3, TrainingLocation="MelWood"},                    new Training {TrainingDuration = 2, TrainingLocation="Anfield"},                    new Training {TrainingDuration = 2, TrainingLocation="MelWood"},                }                            },                            new Footballer {                                  FirstName = "Jamie",LastName="Garragher", Height=1.89, Weight=89,Age=34, JoinedTheClub=DateTime.Parse("12/02/2000"),Positions=FootballPositions.Defender,                Trainings = new List<Training>                                             {                                 new Training {TrainingDuration = 3, TrainingLocation="MelWood"},                new Training {TrainingDuration = 5, TrainingLocation="Anfield"},                new Training {TrainingDuration = 6, TrainingLocation="Anfield"},                }                           }                    };            footballers.ForEach(foot => ctx.Footballers.Add(foot));            ctx.SaveChanges();        }   12) In the Page_Load() event handling routine I called the Insert() method.        protected void Page_Load(object sender, EventArgs e)        {                   Insert();                }  13) Run your application and you will see that the following result,hopefully. You can see clearly that the data is returned along with the enum value.  14) You must have also a look at the database.Launch SSMS and see the database and its objects (data) created from EF Code First.Have a look at the picture below. Hopefully now you have seen the support that exists in EF 5.0 for enums.Hope it helps !!!

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  • Why should main() be short?

    - by Stargazer712
    I've been programming for over 9 years, and according to the advice of my first programming teacher, I always keep my main() function extremely short. At first I had no idea why. I just obeyed without understanding, much to the delight of my professors. After gaining experience, I realized that if I designed my code correctly, having a short main() function just sortof happened. Writing modularized code and following the single responsibility principle allowed my code to be designed in "bunches", and main() served as nothing more than a catalyst to get the program running. Fast forward to a few weeks ago, I was looking at Python's souce code, and I found the main() function: /* Minimal main program -- everything is loaded from the library */ ... int main(int argc, char **argv) { ... return Py_Main(argc, argv); } Yay Python. Short main() function == Good code. Programming teachers were right. Wanting to look deeper, I took a look at Py_Main. In its entirety, it is defined as follows: /* Main program */ int Py_Main(int argc, char **argv) { int c; int sts; char *command = NULL; char *filename = NULL; char *module = NULL; FILE *fp = stdin; char *p; int unbuffered = 0; int skipfirstline = 0; int stdin_is_interactive = 0; int help = 0; int version = 0; int saw_unbuffered_flag = 0; PyCompilerFlags cf; cf.cf_flags = 0; orig_argc = argc; /* For Py_GetArgcArgv() */ orig_argv = argv; #ifdef RISCOS Py_RISCOSWimpFlag = 0; #endif PySys_ResetWarnOptions(); while ((c = _PyOS_GetOpt(argc, argv, PROGRAM_OPTS)) != EOF) { if (c == 'c') { /* -c is the last option; following arguments that look like options are left for the command to interpret. */ command = (char *)malloc(strlen(_PyOS_optarg) + 2); if (command == NULL) Py_FatalError( "not enough memory to copy -c argument"); strcpy(command, _PyOS_optarg); strcat(command, "\n"); break; } if (c == 'm') { /* -m is the last option; following arguments that look like options are left for the module to interpret. */ module = (char *)malloc(strlen(_PyOS_optarg) + 2); if (module == NULL) Py_FatalError( "not enough memory to copy -m argument"); strcpy(module, _PyOS_optarg); break; } switch (c) { case 'b': Py_BytesWarningFlag++; break; case 'd': Py_DebugFlag++; break; case '3': Py_Py3kWarningFlag++; if (!Py_DivisionWarningFlag) Py_DivisionWarningFlag = 1; break; case 'Q': if (strcmp(_PyOS_optarg, "old") == 0) { Py_DivisionWarningFlag = 0; break; } if (strcmp(_PyOS_optarg, "warn") == 0) { Py_DivisionWarningFlag = 1; break; } if (strcmp(_PyOS_optarg, "warnall") == 0) { Py_DivisionWarningFlag = 2; break; } if (strcmp(_PyOS_optarg, "new") == 0) { /* This only affects __main__ */ cf.cf_flags |= CO_FUTURE_DIVISION; /* And this tells the eval loop to treat BINARY_DIVIDE as BINARY_TRUE_DIVIDE */ _Py_QnewFlag = 1; break; } fprintf(stderr, "-Q option should be `-Qold', " "`-Qwarn', `-Qwarnall', or `-Qnew' only\n"); return usage(2, argv[0]); /* NOTREACHED */ case 'i': Py_InspectFlag++; Py_InteractiveFlag++; break; /* case 'J': reserved for Jython */ case 'O': Py_OptimizeFlag++; break; case 'B': Py_DontWriteBytecodeFlag++; break; case 's': Py_NoUserSiteDirectory++; break; case 'S': Py_NoSiteFlag++; break; case 'E': Py_IgnoreEnvironmentFlag++; break; case 't': Py_TabcheckFlag++; break; case 'u': unbuffered++; saw_unbuffered_flag = 1; break; case 'v': Py_VerboseFlag++; break; #ifdef RISCOS case 'w': Py_RISCOSWimpFlag = 1; break; #endif case 'x': skipfirstline = 1; break; /* case 'X': reserved for implementation-specific arguments */ case 'U': Py_UnicodeFlag++; break; case 'h': case '?': help++; break; case 'V': version++; break; case 'W': PySys_AddWarnOption(_PyOS_optarg); break; /* This space reserved for other options */ default: return usage(2, argv[0]); /*NOTREACHED*/ } } if (help) return usage(0, argv[0]); if (version) { fprintf(stderr, "Python %s\n", PY_VERSION); return 0; } if (Py_Py3kWarningFlag && !Py_TabcheckFlag) /* -3 implies -t (but not -tt) */ Py_TabcheckFlag = 1; if (!Py_InspectFlag && (p = Py_GETENV("PYTHONINSPECT")) && *p != '\0') Py_InspectFlag = 1; if (!saw_unbuffered_flag && (p = Py_GETENV("PYTHONUNBUFFERED")) && *p != '\0') unbuffered = 1; if (!Py_NoUserSiteDirectory && (p = Py_GETENV("PYTHONNOUSERSITE")) && *p != '\0') Py_NoUserSiteDirectory = 1; if ((p = Py_GETENV("PYTHONWARNINGS")) && *p != '\0') { char *buf, *warning; buf = (char *)malloc(strlen(p) + 1); if (buf == NULL) Py_FatalError( "not enough memory to copy PYTHONWARNINGS"); strcpy(buf, p); for (warning = strtok(buf, ","); warning != NULL; warning = strtok(NULL, ",")) PySys_AddWarnOption(warning); free(buf); } if (command == NULL && module == NULL && _PyOS_optind < argc && strcmp(argv[_PyOS_optind], "-") != 0) { #ifdef __VMS filename = decc$translate_vms(argv[_PyOS_optind]); if (filename == (char *)0 || filename == (char *)-1) filename = argv[_PyOS_optind]; #else filename = argv[_PyOS_optind]; #endif } stdin_is_interactive = Py_FdIsInteractive(stdin, (char *)0); if (unbuffered) { #if defined(MS_WINDOWS) || defined(__CYGWIN__) _setmode(fileno(stdin), O_BINARY); _setmode(fileno(stdout), O_BINARY); #endif #ifdef HAVE_SETVBUF setvbuf(stdin, (char *)NULL, _IONBF, BUFSIZ); setvbuf(stdout, (char *)NULL, _IONBF, BUFSIZ); setvbuf(stderr, (char *)NULL, _IONBF, BUFSIZ); #else /* !HAVE_SETVBUF */ setbuf(stdin, (char *)NULL); setbuf(stdout, (char *)NULL); setbuf(stderr, (char *)NULL); #endif /* !HAVE_SETVBUF */ } else if (Py_InteractiveFlag) { #ifdef MS_WINDOWS /* Doesn't have to have line-buffered -- use unbuffered */ /* Any set[v]buf(stdin, ...) screws up Tkinter :-( */ setvbuf(stdout, (char *)NULL, _IONBF, BUFSIZ); #else /* !MS_WINDOWS */ #ifdef HAVE_SETVBUF setvbuf(stdin, (char *)NULL, _IOLBF, BUFSIZ); setvbuf(stdout, (char *)NULL, _IOLBF, BUFSIZ); #endif /* HAVE_SETVBUF */ #endif /* !MS_WINDOWS */ /* Leave stderr alone - it should be unbuffered anyway. */ } #ifdef __VMS else { setvbuf (stdout, (char *)NULL, _IOLBF, BUFSIZ); } #endif /* __VMS */ #ifdef __APPLE__ /* On MacOS X, when the Python interpreter is embedded in an application bundle, it gets executed by a bootstrapping script that does os.execve() with an argv[0] that's different from the actual Python executable. This is needed to keep the Finder happy, or rather, to work around Apple's overly strict requirements of the process name. However, we still need a usable sys.executable, so the actual executable path is passed in an environment variable. See Lib/plat-mac/bundlebuiler.py for details about the bootstrap script. */ if ((p = Py_GETENV("PYTHONEXECUTABLE")) && *p != '\0') Py_SetProgramName(p); else Py_SetProgramName(argv[0]); #else Py_SetProgramName(argv[0]); #endif Py_Initialize(); if (Py_VerboseFlag || (command == NULL && filename == NULL && module == NULL && stdin_is_interactive)) { fprintf(stderr, "Python %s on %s\n", Py_GetVersion(), Py_GetPlatform()); if (!Py_NoSiteFlag) fprintf(stderr, "%s\n", COPYRIGHT); } if (command != NULL) { /* Backup _PyOS_optind and force sys.argv[0] = '-c' */ _PyOS_optind--; argv[_PyOS_optind] = "-c"; } if (module != NULL) { /* Backup _PyOS_optind and force sys.argv[0] = '-c' so that PySys_SetArgv correctly sets sys.path[0] to '' rather than looking for a file called "-m". See tracker issue #8202 for details. */ _PyOS_optind--; argv[_PyOS_optind] = "-c"; } PySys_SetArgv(argc-_PyOS_optind, argv+_PyOS_optind); if ((Py_InspectFlag || (command == NULL && filename == NULL && module == NULL)) && isatty(fileno(stdin))) { PyObject *v; v = PyImport_ImportModule("readline"); if (v == NULL) PyErr_Clear(); else Py_DECREF(v); } if (command) { sts = PyRun_SimpleStringFlags(command, &cf) != 0; free(command); } else if (module) { sts = RunModule(module, 1); free(module); } else { if (filename == NULL && stdin_is_interactive) { Py_InspectFlag = 0; /* do exit on SystemExit */ RunStartupFile(&cf); } /* XXX */ sts = -1; /* keep track of whether we've already run __main__ */ if (filename != NULL) { sts = RunMainFromImporter(filename); } if (sts==-1 && filename!=NULL) { if ((fp = fopen(filename, "r")) == NULL) { fprintf(stderr, "%s: can't open file '%s': [Errno %d] %s\n", argv[0], filename, errno, strerror(errno)); return 2; } else if (skipfirstline) { int ch; /* Push back first newline so line numbers remain the same */ while ((ch = getc(fp)) != EOF) { if (ch == '\n') { (void)ungetc(ch, fp); break; } } } { /* XXX: does this work on Win/Win64? (see posix_fstat) */ struct stat sb; if (fstat(fileno(fp), &sb) == 0 && S_ISDIR(sb.st_mode)) { fprintf(stderr, "%s: '%s' is a directory, cannot continue\n", argv[0], filename); fclose(fp); return 1; } } } if (sts==-1) { /* call pending calls like signal handlers (SIGINT) */ if (Py_MakePendingCalls() == -1) { PyErr_Print(); sts = 1; } else { sts = PyRun_AnyFileExFlags( fp, filename == NULL ? "<stdin>" : filename, filename != NULL, &cf) != 0; } } } /* Check this environment variable at the end, to give programs the * opportunity to set it from Python. */ if (!Py_InspectFlag && (p = Py_GETENV("PYTHONINSPECT")) && *p != '\0') { Py_InspectFlag = 1; } if (Py_InspectFlag && stdin_is_interactive && (filename != NULL || command != NULL || module != NULL)) { Py_InspectFlag = 0; /* XXX */ sts = PyRun_AnyFileFlags(stdin, "<stdin>", &cf) != 0; } Py_Finalize(); #ifdef RISCOS if (Py_RISCOSWimpFlag) fprintf(stderr, "\x0cq\x0c"); /* make frontend quit */ #endif #ifdef __INSURE__ /* Insure++ is a memory analysis tool that aids in discovering * memory leaks and other memory problems. On Python exit, the * interned string dictionary is flagged as being in use at exit * (which it is). Under normal circumstances, this is fine because * the memory will be automatically reclaimed by the system. Under * memory debugging, it's a huge source of useless noise, so we * trade off slower shutdown for less distraction in the memory * reports. -baw */ _Py_ReleaseInternedStrings(); #endif /* __INSURE__ */ return sts; } Good God Almighty...it is big enough to sink the Titanic. It seems as though Python did the "Intro to Programming 101" trick and just moved all of main()'s code to a different function called it something very similar to "main". Here's my question: Is this code terribly written, or are there other reasons reasons to have a short main function? As it stands right now, I see absolutely no difference between doing this and just moving the code in Py_Main() back into main(). Am I wrong in thinking this?

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  • DevConnections Session Slides, Samples and Links

    - by Rick Strahl
    Finally coming up for air this week, after catching up with being on the road for the better part of three weeks. Here are my slides, samples and links for my four DevConnections Session two weeks ago in Vegas. I ended up doing one extra un-prepared for session on WebAPI and AJAX, as some of the speakers were either delayed or unable to make it at all to Vegas due to Sandy's mayhem. It was pretty hectic in the speaker room as Erik (our event coordinator extrodinaire) was scrambling to fill session slots with speakers :-). Surprisingly it didn't feel like the storm affected attendance drastically though, but I guess it's hard to tell without actual numbers. The conference was a lot of fun - it's been a while since I've been speaking at one of these larger conferences. I'd been taking a hiatus, and I forgot how much I enjoy actually giving talks. Preparing - well not  quite so much, especially since I ended up essentially preparing or completely rewriting for all three of these talks and I was stressing out a bit as I was sick the week before the conference and didn't get as much time to prepare as I wanted to. But - as always seems to be the case - it all worked out, but I guess those that attended have to be the judge of that… It was great to catch up with my speaker friends as well - man I feel out of touch. I got to spend a bunch of time with Dan Wahlin, Ward Bell, Julie Lerman and for about 10 minutes even got to catch up with the ever so busy Michele Bustamante. Lots of great technical discussions including a fun and heated REST controversy with Ward and Howard Dierking. There were also a number of great discussions with attendees, describing how they're using the technologies touched in my talks in live applications. I got some great ideas from some of these and I wish there would have been more opportunities for these kinds of discussions. One thing I miss at these Vegas events though is some sort of coherent event where attendees and speakers get to mingle. These Vegas conferences are just like "go to sessions, then go out and PARTY on the town" - it's Vegas after all! But I think that it's always nice to have at least one evening event where everybody gets to hang out together and trade stories and geek talk. Overall there didn't seem to be much opportunity for that beyond lunch or the small and short exhibit hall events which it seemed not many people actually went to. Anyways, a good time was had. I hope those of you that came to my sessions learned something useful. There were lots of great questions and discussions after the sessions - always appreciate hearing the real life scenarios that people deal with in relation to the abstracted scenarios in sessions. Here are the Session abstracts, a few comments and the links for downloading slides and  samples. It's not quite like being there, but I hope this stuff turns out to be useful to some of you. I'll be following up a couple of these sessions with white papers in the following weeks. Enjoy. ASP.NET Architecture: How ASP.NET Works at the Low Level Abstract:Interested in how ASP.NET works at a low level? ASP.NET is extremely powerful and flexible technology, but it's easy to forget about the core framework that underlies the higher level technologies like ASP.NET MVC, WebForms, WebPages, Web Services that we deal with on a day to day basis. The ASP.NET core drives all the higher level handlers and frameworks layered on top of it and with the core power comes some complexity in the form of a very rich object model that controls the flow of a request through the ASP.NET pipeline from Windows HTTP services down to the application level. To take full advantage of it, it helps to understand the underlying architecture and model. This session discusses the architecture of ASP.NET along with a number of useful tidbits that you can use for building and debugging your ASP.NET applications more efficiently. We look at overall architecture, how requests flow from the IIS (7 and later) Web Server to the ASP.NET runtime into HTTP handlers, modules and filters and finally into high-level handlers like MVC, Web Forms or Web API. Focus of this session is on the low-level aspects on the ASP.NET runtime, with examples that demonstrate the bootstrapping of ASP.NET, threading models, how Application Domains are used, startup bootstrapping, how configuration files are applied and how all of this relates to the applications you write either using low-level tools like HTTP handlers and modules or high-level pages or services sitting at the top of the ASP.NET runtime processing chain. Comments:I was surprised to see so many people show up for this session - especially since it was the last session on the last day and a short 1 hour session to boot. The room was packed and it was to see so many people interested the abstracts of architecture of ASP.NET beyond the immediate high level application needs. Lots of great questions in this talk as well - I only wish this session would have been the full hour 15 minutes as we just a little short of getting through the main material (didn't make it to Filters and Error handling). I haven't done this session in a long time and I had to pretty much re-figure all the system internals having to do with the ASP.NET bootstrapping in light for the changes that came with IIS 7 and later. The last time I did this talk was with IIS6, I guess it's been a while. I love doing this session, mainly because in my mind the core of ASP.NET overall is so cleanly designed to provide maximum flexibility without compromising performance that has clearly stood the test of time in the 10 years or so that .NET has been around. While there are a lot of moving parts, the technology is easy to manage once you understand the core components and the core model hasn't changed much even while the underlying architecture that drives has been almost completely revamped especially with the introduction of IIS 7 and later. Download Samples and Slides   Introduction to using jQuery with ASP.NET Abstract:In this session you'll learn how to take advantage of jQuery in your ASP.NET applications. Starting with an overview of jQuery client features via many short and fun examples, you'll find out about core features like the power of selectors for document element selection, manipulating these elements with jQuery's wrapped set methods in a browser independent way, how to hook up and handle events easily and generally apply concepts of unobtrusive JavaScript principles to client scripting. The second half of the session then delves into jQuery's AJAX features and several different ways how you can interact with ASP.NET on the server. You'll see examples of using ASP.NET MVC for serving HTML and JSON AJAX content, as well as using the new ASP.NET Web API to serve JSON and hypermedia content. You'll also see examples of client side templating/databinding with Handlebars and Knockout. Comments:This session was in a monster of a room and to my surprise it was nearly packed, given that this was a 100 level session. I can see that it's a good idea to continue to do intro sessions to jQuery as there appeared to be quite a number of folks who had not worked much with jQuery yet and who most likely could greatly benefit from using it. Seemed seemed to me the session got more than a few people excited to going if they hadn't yet :-).  Anyway I just love doing this session because it's mostly live coding and highly interactive - not many sessions that I can build things up from scratch and iterate on in an hour. jQuery makes that easy though. Resources: Slides and Code Samples Introduction to jQuery White Paper Introduction to ASP.NET Web API   Hosting the Razor Scripting Engine in Your Own Applications Abstract:The Razor Engine used in ASP.NET MVC and ASP.NET Web Pages is a free-standing scripting engine that can be disassociated from these Web-specific implementations and can be used in your own applications. Razor allows for a powerful mix of code and text rendering that makes it a wonderful tool for any sort of text generation, from creating HTML output in non-Web applications, to rendering mail merge-like functionality, to code generation for developer tools and even as a plug-in scripting engine. In this session, we'll look at the components that make up the Razor engine and how you can bootstrap it in your own applications to hook up templating. You'll find out how to create custom templates and manage Razor requests that can be pre-compiled, detecting page changes and act in ways similar to a full runtime. We look at ways that you can pass data into the engine and retrieve both the rendered output as well as result values in a package that makes it easy to plug Razor into your own applications. Comments:That this session was picked was a bit of a surprise to me, since it's a bit of a niche topic. Even more of a surprise was that during the session quite a few people who attended had actually used Razor externally and were there to find out more about how the process works and how to extend it. In the session I talk a bit about a custom Razor hosting implementation (Westwind.RazorHosting) and drilled into the various components required to build a custom Razor Hosting engine and a runtime around it. This sessions was a bit of a chore to prepare for as there are lots of technical implementation details that needed to be dealt with and squeezing that into an hour 15 is a bit tight (and that aren't addressed even by some of the wrapper libraries that exist). Found out though that there's quite a bit of interest in using a templating engine outside of web applications, or often side by side with the HTML output generated by frameworks like MVC or WebForms. An extra fun part of this session was that this was my first session and when I went to set up I realized I forgot my mini-DVI to VGA adapter cable to plug into the projector in my room - 6 minutes before the session was about to start. So I ended up sprinting the half a mile + back to my room - and back at a full sprint. I managed to be back only a couple of minutes late, but when I started I was out of breath for the first 10 minutes or so, while trying to talk. Musta sounded a bit funny as I was trying to not gasp too much :-) Resources: Slides and Code Samples Westwind.RazorHosting GitHub Project Original RazorHosting Blog Post   Introduction to ASP.NET Web API for AJAX Applications Abstract:WebAPI provides a new framework for creating REST based APIs, but it can also act as a backend to typical AJAX operations. This session covers the core features of Web API as it relates to typical AJAX application development. We’ll cover content-negotiation, routing and a variety of output generation options as well as managing data updates from the client in the context of a small Single Page Application style Web app. Finally we’ll look at some of the extensibility features in WebAPI to customize and extend Web API in a number and useful useful ways. Comments:This session was a fill in for session slots not filled due MIA speakers stranded by Sandy. I had samples from my previous Web API article so decided to go ahead and put together a session from it. Given that I spent only a couple of hours preparing and putting slides together I was glad it turned out as it did - kind of just ran itself by way of the examples I guess as well as nice audience interactions and questions. Lots of interest - and also some confusion about when Web API makes sense. Both this session and the jQuery session ended up getting a ton of questions about when to use Web API vs. MVC, whether it would make sense to switch to Web API for all AJAX backend work etc. In my opinion there's no need to jump to Web API for existing applications that already have a good AJAX foundation. Web API is awesome for real externally consumed APIs and clearly defined application AJAX APIs. For typical application level AJAX calls, it's still a good idea, but ASP.NET MVC can serve most if not all of that functionality just as well. There's no need to abandon MVC (or even ASP.NET AJAX or third party AJAX backends) just to move to Web API. For new projects Web API probably makes good sense for isolation of AJAX calls, but it really depends on how the application is set up. In some cases sharing business logic between the HTML and AJAX interfaces with a single MVC API can be cleaner than creating two completely separate code paths to serve essentially the same business logic. Resources: Slides and Code Samples Sample Code on GitHub Introduction to ASP.NET Web API White Paper© Rick Strahl, West Wind Technologies, 2005-2012Posted in Conferences  ASP.NET   Tweet !function(d,s,id){var js,fjs=d.getElementsByTagName(s)[0];if(!d.getElementById(id)){js=d.createElement(s);js.id=id;js.src="//platform.twitter.com/widgets.js";fjs.parentNode.insertBefore(js,fjs);}}(document,"script","twitter-wjs"); (function() { var po = document.createElement('script'); po.type = 'text/javascript'; po.async = true; po.src = 'https://apis.google.com/js/plusone.js'; var s = document.getElementsByTagName('script')[0]; s.parentNode.insertBefore(po, s); })();

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  • Testing Entity Framework applications, pt. 3: NDbUnit

    - by Thomas Weller
    This is the third of a three part series that deals with the issue of faking test data in the context of a legacy app that was built with Microsoft's Entity Framework (EF) on top of an MS SQL Server database – a scenario that can be found very often. Please read the first part for a description of the sample application, a discussion of some general aspects of unit testing in a database context, and of some more specific aspects of the here discussed EF/MSSQL combination. Lately, I wondered how you would ‘mock’ the data layer of a legacy application, when this data layer is made up of an MS Entity Framework (EF) model in combination with a MS SQL Server database. Originally, this question came up in the context of how you could enable higher-level integration tests (automated UI tests, to be exact) for a legacy application that uses this EF/MSSQL combo as its data store mechanism – a not so uncommon scenario. The question sparked my interest, and I decided to dive into it somewhat deeper. What I've found out is, in short, that it's not very easy and straightforward to do it – but it can be done. The two strategies that are best suited to fit the bill involve using either the (commercial) Typemock Isolator tool or the (free) NDbUnit framework. The use of Typemock was discussed in the previous post, this post now will present the NDbUnit approach... NDbUnit is an Apache 2.0-licensed open-source project, and like so many other Nxxx tools and frameworks, it is basically a C#/.NET port of the corresponding Java version (DbUnit namely). In short, it helps you in flexibly managing the state of a database in that it lets you easily perform basic operations (like e.g. Insert, Delete, Refresh, DeleteAll)  against your database and, most notably, lets you feed it with data from external xml files. Let's have a look at how things can be done with the help of this framework. Preparing the test data Compared to Typemock, using NDbUnit implies a totally different approach to meet our testing needs.  So the here described testing scenario requires an instance of an SQL Server database in operation, and it also means that the Entity Framework model that sits on top of this database is completely unaffected. First things first: For its interactions with the database, NDbUnit relies on a .NET Dataset xsd file. See Step 1 of their Quick Start Guide for a description of how to create one. With this prerequisite in place then, the test fixture's setup code could look something like this: [TestFixture, TestsOn(typeof(PersonRepository))] [Metadata("NDbUnit Quickstart URL",           "http://code.google.com/p/ndbunit/wiki/QuickStartGuide")] [Description("Uses the NDbUnit library to provide test data to a local database.")] public class PersonRepositoryFixture {     #region Constants     private const string XmlSchema = @"..\..\TestData\School.xsd";     #endregion // Constants     #region Fields     private SchoolEntities _schoolContext;     private PersonRepository _personRepository;     private INDbUnitTest _database;     #endregion // Fields     #region Setup/TearDown     [FixtureSetUp]     public void FixtureSetUp()     {         var connectionString = ConfigurationManager.ConnectionStrings["School_Test"].ConnectionString;         _database = new SqlDbUnitTest(connectionString);         _database.ReadXmlSchema(XmlSchema);         var entityConnectionStringBuilder = new EntityConnectionStringBuilder         {             Metadata = "res://*/School.csdl|res://*/School.ssdl|res://*/School.msl",             Provider = "System.Data.SqlClient",             ProviderConnectionString = connectionString         };         _schoolContext = new SchoolEntities(entityConnectionStringBuilder.ConnectionString);         _personRepository = new PersonRepository(this._schoolContext);     }     [FixtureTearDown]     public void FixtureTearDown()     {         _database.PerformDbOperation(DbOperationFlag.DeleteAll);         _schoolContext.Dispose();     }     ...  As you can see, there is slightly more fixture setup code involved if your tests are using NDbUnit to provide the test data: Because we're dealing with a physical database instance here, we first need to pick up the test-specific connection string from the test assemblies' App.config, then initialize an NDbUnit helper object with this connection along with the provided xsd file, and also set up the SchoolEntities and the PersonRepository instances accordingly. The _database field (an instance of the INdUnitTest interface) will be our single access point to the underlying database: We use it to perform all the required operations against the data store. To have a flexible mechanism to easily insert data into the database, we can write a helper method like this: private void InsertTestData(params string[] dataFileNames) {     _database.PerformDbOperation(DbOperationFlag.DeleteAll);     if (dataFileNames == null)     {         return;     }     try     {         foreach (string fileName in dataFileNames)         {             if (!File.Exists(fileName))             {                 throw new FileNotFoundException(Path.GetFullPath(fileName));             }             _database.ReadXml(fileName);             _database.PerformDbOperation(DbOperationFlag.InsertIdentity);         }     }     catch     {         _database.PerformDbOperation(DbOperationFlag.DeleteAll);         throw;     } } This lets us easily insert test data from xml files, in any number and in a  controlled order (which is important because we eventually must fulfill referential constraints, or we must account for some other stuff that imposes a specific ordering on data insertion). Again, as with Typemock, I won't go into API details here. - Unfortunately, there isn't too much documentation for NDbUnit anyway, other than the already mentioned Quick Start Guide (and the source code itself, of course) - a not so uncommon problem with smaller Open Source Projects. Last not least, we need to provide the required test data in xml form. A snippet for data from the People table might look like this, for example: <?xml version="1.0" encoding="utf-8" ?> <School xmlns="http://tempuri.org/School.xsd">   <Person>     <PersonID>1</PersonID>     <LastName>Abercrombie</LastName>     <FirstName>Kim</FirstName>     <HireDate>1995-03-11T00:00:00</HireDate>   </Person>   <Person>     <PersonID>2</PersonID>     <LastName>Barzdukas</LastName>     <FirstName>Gytis</FirstName>     <EnrollmentDate>2005-09-01T00:00:00</EnrollmentDate>   </Person>   <Person>     ... You can also have data from various tables in one single xml file, if that's appropriate for you (but beware of the already mentioned ordering issues). It's true that your test assembly may end up with dozens of such xml files, each containing quite a big amount of text data. But because the files are of very low complexity, and with the help of a little bit of Copy/Paste and Excel magic, this appears to be well manageable. Executing some basic tests Here are some of the possible tests that can be written with the above preparations in place: private const string People = @"..\..\TestData\School.People.xml"; ... [Test, MultipleAsserts, TestsOn("PersonRepository.GetNameList")] public void GetNameList_ListOrdering_ReturnsTheExpectedFullNames() {     InsertTestData(People);     List<string> names =         _personRepository.GetNameList(NameOrdering.List);     Assert.Count(34, names);     Assert.AreEqual("Abercrombie, Kim", names.First());     Assert.AreEqual("Zheng, Roger", names.Last()); } [Test, MultipleAsserts, TestsOn("PersonRepository.GetNameList")] [DependsOn("RemovePerson_CalledOnce_DecreasesCountByOne")] public void GetNameList_NormalOrdering_ReturnsTheExpectedFullNames() {     InsertTestData(People);     List<string> names =         _personRepository.GetNameList(NameOrdering.Normal);     Assert.Count(34, names);     Assert.AreEqual("Alexandra Walker", names.First());     Assert.AreEqual("Yan Li", names.Last()); } [Test, TestsOn("PersonRepository.AddPerson")] public void AddPerson_CalledOnce_IncreasesCountByOne() {     InsertTestData(People);     int count = _personRepository.Count;     _personRepository.AddPerson(new Person { FirstName = "Thomas", LastName = "Weller" });     Assert.AreEqual(count + 1, _personRepository.Count); } [Test, TestsOn("PersonRepository.RemovePerson")] public void RemovePerson_CalledOnce_DecreasesCountByOne() {     InsertTestData(People);     int count = _personRepository.Count;     _personRepository.RemovePerson(new Person { PersonID = 33 });     Assert.AreEqual(count - 1, _personRepository.Count); } Not much difference here compared to the corresponding Typemock versions, except that we had to do a bit more preparational work (and also it was harder to get the required knowledge). But this picture changes quite dramatically if we look at some more demanding test cases: Ok, and what if things are becoming somewhat more complex? Tests like the above ones represent the 'easy' scenarios. They may account for the biggest portion of real-world use cases of the application, and they are important to make sure that it is generally sound. But usually, all these nasty little bugs originate from the more complex parts of our code, or they occur when something goes wrong. So, for a testing strategy to be of real practical use, it is especially important to see how easy or difficult it is to mimick a scenario which represents a more complex or exceptional case. The following test, for example, deals with the case that there is some sort of invalid input from the caller: [Test, MultipleAsserts, TestsOn("PersonRepository.GetCourseMembers")] [Row(null, typeof(ArgumentNullException))] [Row("", typeof(ArgumentException))] [Row("NotExistingCourse", typeof(ArgumentException))] public void GetCourseMembers_WithGivenVariousInvalidValues_Throws(string courseTitle, Type expectedInnerExceptionType) {     var exception = Assert.Throws<RepositoryException>(() =>                                 _personRepository.GetCourseMembers(courseTitle));     Assert.IsInstanceOfType(expectedInnerExceptionType, exception.InnerException); } Apparently, this test doesn't need an 'Arrange' part at all (see here for the same test with the Typemock tool). It acts just like any other client code, and all the required business logic comes from the database itself. This doesn't always necessarily mean that there is less complexity, but only that the complexity happens in a different part of your test resources (in the xml files namely, where you sometimes have to spend a lot of effort for carefully preparing the required test data). Another example, which relies on an underlying 1-n relationship, might be this: [Test, MultipleAsserts, TestsOn("PersonRepository.GetCourseMembers")] public void GetCourseMembers_WhenGivenAnExistingCourse_ReturnsListOfStudents() {     InsertTestData(People, Course, Department, StudentGrade);     List<Person> persons = _personRepository.GetCourseMembers("Macroeconomics");     Assert.Count(4, persons);     Assert.ForAll(         persons,         @p => new[] { 10, 11, 12, 14 }.Contains(@p.PersonID),         "Person has none of the expected IDs."); } If you compare this test to its corresponding Typemock version, you immediately see that the test itself is much simpler, easier to read, and thus much more intention-revealing. The complexity here lies hidden behind the call to the InsertTestData() helper method and the content of the used xml files with the test data. And also note that you might have to provide additional data which are not even directly relevant to your test, but are required only to fulfill some integrity needs of the underlying database. Conclusion The first thing to notice when comparing the NDbUnit approach to its Typemock counterpart obviously deals with performance: Of course, NDbUnit is much slower than Typemock. Technically,  it doesn't even make sense to compare the two tools. But practically, it may well play a role and could or could not be an issue, depending on how much tests you have of this kind, how often you run them, and what role they play in your development cycle. Also, because the dataset from the required xsd file must fully match the database schema (even in parts that otherwise wouldn't be relevant to you), it can be quite cumbersome to be in a team where different people are working with the database in parallel. My personal experience is – as already said in the first part – that Typemock gives you a better development experience in a 'dynamic' scenario (when you're working in some kind of TDD-style, you're oftentimes executing the tests from your dev box, and your database schema changes frequently), whereas the NDbUnit approach is a good and solid solution in more 'static' development scenarios (when you need to execute the tests less frequently or only on a separate build server, and/or the underlying database schema can be kept relatively stable), for example some variations of higher-level integration or User-Acceptance tests. But in any case, opening Entity Framework based applications for testing requires a fair amount of resources, planning, and preparational work – it's definitely not the kind of stuff that you would call 'easy to test'. Hopefully, future versions of EF will take testing concerns into account. Otherwise, I don't see too much of a future for the framework in the long run, even though it's quite popular at the moment... The sample solution A sample solution (VS 2010) with the code from this article series is available via my Bitbucket account from here (Bitbucket is a hosting site for Mercurial repositories. The repositories may also be accessed with the Git and Subversion SCMs - consult the documentation for details. In addition, it is possible to download the solution simply as a zipped archive – via the 'get source' button on the very right.). The solution contains some more tests against the PersonRepository class, which are not shown here. Also, it contains database scripts to create and fill the School sample database. To compile and run, the solution expects the Gallio/MbUnit framework to be installed (which is free and can be downloaded from here), the NDbUnit framework (which is also free and can be downloaded from here), and the Typemock Isolator tool (a fully functional 30day-trial is available here). Moreover, you will need an instance of the Microsoft SQL Server DBMS, and you will have to adapt the connection strings in the test projects App.config files accordingly.

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  • CodePlex Daily Summary for Tuesday, November 08, 2011

    CodePlex Daily Summary for Tuesday, November 08, 2011Popular ReleasesFacebook C# SDK: v5.3.2: This is a RTW release which adds new features and bug fixes to v5.2.1. Query/QueryAsync methods uses graph api instead of legacy rest api. removed dependency from Code Contracts enabled Task Parallel Support in .NET 4.0+ (experimental) added support for early preview for .NET 4.5 (binaries not distributed in codeplex nor nuget.org, will need to manually build from Facebook-Net45.sln) added additional method overloads for .NET 4.5 to support IProgress<T> for upload progress added ne...Delete Inactive TS Ports: List and delete the Inactive TS Ports: List and delete the Inactive TS Ports - The InactiveTSPortList.EXE accepts command line arguments The InactiveTSPortList.Standalone.WithoutPrompt.exe runs as a standalone exe without the need for any command line arguments.ClosedXML - The easy way to OpenXML: ClosedXML 0.60.0: Added almost full support for auto filters (missing custom date filters). See examples Filter Values, Custom Filters Fixed issues 7016, 7391, 7388, 7389, 7198, 7196, 7194, 7186, 7067, 7115, 7144Microsoft Research Boogie: Nightly builds: This download category contains automatically released nightly builds, reflecting the current state of Boogie's development. We try to make sure each nightly build passes the test suite. If you suspect that was not the case, please try the previous nightly build to see if that really is the problem. Also, please see the installation instructions.DotSpatial: Release 821: Updated releaseGoogleMap Control: GoogleMap Control 6.0: Major design changes to the control in order to achieve better scalability and extensibility for the new features comming with GoogleMaps API. GoogleMap control switched to GoogleMaps API v3 and .NET 4.0. GoogleMap control is 100% ScriptControl now, it requires ScriptManager to be registered on the pages where and before it is used. Markers, polylines, polygons and directions were implemented as ExtenderControl, instead of being inner properties of GoogleMap control. Better perfomance. Better...WDTVHubGen - Adds Metadata, thumbnails and subtitles to WDTV Live Hubs: V2.1: Version 2.1 (click on the right) this uses V4.0 of .net Version 2.1 adds the following features: (apologize if I forget some, added a lot of little things) Manual Lookup with TV or Movie (finally huh!), you can look up a movie or TV episode directly, you can right click on anythign, and choose manual lookup, then will allow you to type anything you want to look up and it will assign it to the file you right clicked. No Rename: a very popular request, this is an option you can set so that t...SubExtractor: Release 1020: Feature: added "baseline double quotes" character to selector box Feature: added option to save SRT files as ANSI (instead of previous UTF-8 only) Feature: made "Save Sup files to Source directory" apply to both Sup and Idx source files. Fix: removed SDH text (...) or [...] that is split over 2 lines Fix: better decision-making in when to prefix a line with a '-' because SDH was removedAcDown????? - Anime&Comic Downloader: AcDown????? v3.6.1: ?? ● AcDown??????????、??????,??????????????????????,???????Acfun、Bilibili、???、???、???、Tucao.cc、SF???、?????80????,???????????、?????????。 ● AcDown???????????????????????????,???,???????????????????。 ● AcDown???????C#??,????.NET Framework 2.0??。?????"Acfun?????"。 ????32??64? Windows XP/Vista/7 ????????????? ??:????????Windows XP???,?????????.NET Framework 2.0???(x86)?.NET Framework 2.0???(x64),?????"?????????"??? ??????????????,??????????: ??"AcDown?????"????????? ?? v3.6.1?? ??.hlv...Track Folder Changes: Track Folder Changes 1.1: Fixed exception when right-clicking the root nodeMapWindow 4: MapWindow GIS v4.8.6 - Final release - 32Bit: This is the final release of MapWindow v4.8. It has 4.8.6 as version number. This version has been thoroughly tested. If you do get an exception send the exception to us. Don't forget to include your e-mail address. Use the forums at http://www.mapwindow.org/phorum/ for questions. Please consider donating a small portion of the money you have saved by having free GIS tools: http://www.mapwindow.org/pages/donate.php What’s New in 4.8.6 (Final release) · A few minor issues have been fixed Wha...Kinect Paint: Kinect Paint 1.1: Updated for Kinect for Windows SDK v1.0 Beta 2!Kinect Mouse Cursor: Kinect Mouse Cursor 1.1: Updated for Kinect for Windows SDK v1.0 Beta 2!Coding4Fun Kinect Toolkit: Coding4Fun Kinect Toolkit 1.1: Updated for Kinect for Windows SDK v1.0 Beta 2!Async Executor: 1.0: Source code of the AsyncExecutorMedia Companion: MC 3.421b Weekly: Ensure .NET 4.0 Full Framework is installed. (Available from http://www.microsoft.com/download/en/details.aspx?id=17718) Ensure the NFO ID fix is applied when transitioning from versions prior to 3.416b. (Details here) TV Show Resolutions... Fix to show the season-specials.tbn when selecting an episode from season 00. Before, MC would try & load season00.tbn Fix for issue #197 - new show added by 'Manually Add Path' not being picked up. Also made non-visible the same thing in Root Folders...?????????? - ????????: All-In-One Code Framework ??? 2011-11-02: http://download.codeplex.com/Project/Download/FileDownload.aspx?ProjectName=1codechs&DownloadId=216140 ??????,11??,?????20????Microsoft OneCode Sample,????6?Program Language Sample,2?Windows Base Sample,2?GDI+ Sample,4?Internet Explorer Sample?6?ASP.NET Sample。?????????????。 ????,?????。http://i3.codeplex.com/Project/Download/FileDownload.aspx?ProjectName=1code&DownloadId=128165 Program Language CSImageFullScreenSlideShow VBImageFullScreenSlideShow CSDynamicallyBuildLambdaExpressionWithFie...Python Tools for Visual Studio: 1.1 Alpha: We’re pleased to announce the release of Python Tools for Visual Studio 1.1 Alpha. Python Tools for Visual Studio (PTVS) is an open-source plug-in for Visual Studio which supports programming with the Python programming language. This release includes new core IDE features, a couple of new sample libraries for interacting with Kinect and Excel, and many bug fixes for issues reported since the release of 1.0. For the core IDE features we’ve added many new features which improve the basic edit...BExplorer (Better Explorer): Better Explorer 2.0.0.631 Alpha: Changelog: Added: Some new functions in ribbon Added: Possibility to choose displayed columns Added: Basic Search Fixed: Some bugs after navigation Fixed: Attempt to fix slow navigation and slow start Known issues: - BreadcrumbBar fails on some situations - Basic search does not work well in some situations Please if anyone finds bugs be kind and report them at the Issue Tracker! Thanks!DotNetNuke® Community Edition: 05.06.04: Major Highlights Fixed issue with upgrades on systems that had upgraded the Telerik library to 6.0.0 Fixed issue with Razor Host upgrade to 5.6.3 The logic for module administration checks contains incorrect logic in 1 place, opening the possibility of a user with edit permissions gaining access to functionality they should not have through a particularly crafted url Security FixesBrowsers support the ability to remember common strings such as usernames/addresses etc. Code was adde...New ProjectsAddThis for DotNetNuke: A simple AddThis module (plugin) for DotNetNukeAgnisExchange: <AGNIS>as A Growable Network Infor;ation System is developped in <C#>Blogger auto poster: Do you want to have a links blog? Share your favorites links in Google+ and then allow BAP(Blogger auto poster) to read its JSON feed and post its daily summary at your Blogger weblog automatically. CarbonEmissions: CarbonEmissionsCredivale: CredivaleCRM 2011 TreeView for Lookup: CRM 2011 WebResource Utility for showing Self-Joined Lookup data in TreeView form.Dafuscator: Dafuscator is a database data obfuscation system that allows you to tactically obfuscate or delete data out of your production database while leaving most of the data intact.DigDesDevSchoolHomeSaleSystem: This is study project. Done by Russian students. Use ASP.NET MVC.Dynamic Data Extensions: Dynamic Data Extensions add new features to the current ASP.Net 4 Dynamic Data versionEchosoft NoCrash From Scratch: Nocrash From scratch, a operating system designed (but not promised to be) almost invincible from viruses and %20 Windows-like using DoubleTime emulation to make it act like Windows 2000EdiProj: Just a PHP and Asp.Net project.experteer: decision theory class projectFlan Project: Fast-paced Action-RPG (2D Scrolling)GameXNA_Master: XNA MASETR GD 2011 Gyrf: SecretJogo Da Velha em CSharp: Jogo da velha feito para o curso de c#.Jogo das cores: Projeto da aula de extensão de C#Kookaburra: Kookaburra is a framework based on Windows PowerShell 2.0 that can be used for automating SharePoint 2010 administration. It contains a menu, several functions and a well defined structure for adding PowerShell scriptlets.LaunchWithParams: LaunchWithParams is a Windows Explorer add-on that allows you to launch an application executable with specific command-line parameters without having to open a command prompt.MerchantTribe - Shopping Cart and Ecommerce Platform in C# MVC ASP.NET: MerchantTribe is a free, open-source ASP.NET MVC ecommerce platform in C#. For more than a decade, we've been building and selling commercial .NET shopping cart software. Now, we're releasing an open-source project based on our award winning BV Commerce software. Thousands of companies use our shopping cart include Pebble Beach Resorts, DataPipe, TastyKake, MathBlaster and Chesapeake Energy. We need as many people as possible using MerchantTribe for it to thrive. We need Merchants, De...NaiveAlgorithms: Naive C# implementation of basic, general purpose algorithms, with an emphasis on readability, maintainability and correctness. While asymptotic complexity of algorithms is preserved, there is no premature optimisation performed to improve performance. NeonMikaWebserver: NeonMikaWebserver is easy to set up on your .Net MF device, as long as it has an ethernet port. It's espacially created for the Netduino, but I think it's no big work to port it to other plattforms. It provides the following functionalities: -XML Responses ... Just create an Instance of XMLResponse, give it an URI to listen for and fill a Hashtable with your response keys and values... Voila ;) -File Response ... No XML Response fitting your URL? Probably you want to watch a file sa...Next Action: The Next Action web application is a GTD task manager implemented with using MVC3, jQuery, Entity Framework. Orchard Comments Refactoring: Refactoring Orchard's comments moduleoutsource: outsourceScutex: Scutex, pronounced (sec-u-techs), is a 100% managed .Net Framework licensing platform for your applications. Scutex is a flexible licensing system allowing multiple licensing schemes allowing you the most control over how you licensing your products. Unlike any other licensing system on the market, Scutex provides 4 distinct licensing schemes, allowing you to protect your products at different levels using completely different licensing schemes, key types and protection systems. Using Scut...sigem2: Proyecto sigem2SSDL: An easy way to call and manage stored procedures in .NET.Trabalho C# - Datilografia: Software de datilografia produzido para o curso de extensão em C# da UFSCar Sorocaba.triliporra: Triliporra Euro 2012User Interface Toolkit: Ever dreamed about having one framework to write UI independently of your targetted client ? Now your dream has come true !vimrc: my vimrc fileVisuospatial Web Browsing using Kinect: The Kinect Web Browser project explores how users might use the Kinect sensor as a natural interface to browse the visual web. It's developed in C#.VNManager: VNManager or Version Number Manager is a simple Windows command line application which will update your Microsoft Visual Studio AssemblyInfo.cs files AssemblyVersion and AssemblyFileVersion attributes based on rules defined as comments on the same lines.WeddingAssistant: My site will be a ‘gift wish’ site for couples getting married. It will also be a place where people can come and look at ideas for hen and stag nights. Users log in and create a list of items they wish to receive for their wedding or look for ideas for hen and stag nights. The site will allow users to compile a list of items they have found on the internet from specific listed shops and order them in preference. The compiled list is then sent out to friends and relatives who can create a...WMS.NET: thewms is warehouse manager system! For the logistics industry! The team learning project! Built on the mvc3.0 and wcf ! Using jquery js framework as front endWorkflowRobot: Workflow based automation software.

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  • Using Deployment Manager

    - by Jess Nickson
    One of the teams at Red Gate has been working very hard on a new product: Deployment Manager. Deployment Manager is a free tool that lets you deploy updates to .NET apps, services and databases through a central dashboard. Deployment Manager has been out for a while, but I must admit that even though I work in the same building, until now I hadn’t even looked at it. My job at Red Gate is to develop and maintain some of our community sites, which involves carrying out regular deployments. One of the projects I have to deploy on a fairly regular basis requires me to send my changes to our build server, TeamCity. The output is a Zip file of the build. I then have to go and find this file, copy it across to the staging machine, extract it, and copy some of the sub-folders to other places. In order to keep track of what builds are running, I need to rename the folders accordingly. However, even after all that, I still need to go and update the site and its applications in IIS to point at these new builds. Oh, and then, I have to repeat the process when I deploy on production. Did I mention the multiple configuration files that then need updating as well? Manually? The whole process can take well over half an hour. I’m ready to try out a new process. Deployment Manager is designed to massively simplify the deployment processes from what could be lots of manual copying of files, managing of configuration files, and database upgrades down to a few clicks. It’s a big promise, but I decided to try out this new tool on one of the smaller ASP.NET sites at Red Gate, Format SQL (the result of a Red Gate Down Tools week). I wanted to add some new functionality, but given it was a new site with no set way of doing things, I was reluctant to have to manually copy files around servers. I decided to use this opportunity as a chance to set the site up on Deployment Manager and check out its functionality. What follows is a guide on how to get set up with Deployment Manager, a brief overview of its features, and what I thought of the experience. To follow along with the instructions that follow, you’ll first need to download Deployment Manager from Red Gate. It has a free ‘Starter Edition’ which allows you to create up to 5 projects and agents (machines you deploy to), so it’s really easy to get up and running with a fully-featured version. The Initial Set Up After installing the product and setting it up using the administration tool it provides, I launched Deployment Manager by going to the URL and port I had set it to run on. This loads up the main dashboard. The dashboard does a good job of guiding me through the process of getting started, beginning with a prompt to create some environments. 1. Setting up Environments The dashboard informed me that I needed to add new ‘Environments’, which are essentially ways of grouping the machines you want to deploy to. The environments that get added will show up on the main dashboard. I set up two such environments for this project: ‘staging’ and ‘live’.   2. Add Target Machines Once I had created the environments, I was ready to add ‘target machine’s to them, which are the actual machines that the deployment will occur on.   To enable me to deploy to a new machine, I needed to download and install an Agent on it. The ‘Add target machine’ form on the ‘Environments’ page helpfully provides a link for downloading an Agent.   Once the agent has been installed, it is just a case of copying the server key to the agent, and the agent key to the server, to link them up.   3. Run Health Check If, after adding your new target machine, the ‘Status’ flags an error, it is possible that the Agent and Server keys have not been entered correctly on both Deployment Manager and the Agent service.     You can ‘Check Health’, which will give you more information on any issues. It is probably worth running this regardless of what status the ‘Environments’ dashboard is claiming, just to be on the safe side.     4. Add Projects Going back to the main Dashboard tab at this point, I found that it was telling me that I needed to set up a new project.   I clicked the ‘project’ link to get started, gave my new project a name and clicked ‘Create’. I was then redirected to the ‘Steps’ page for the project under the Projects tab.   5. Package Steps The ‘Steps’ page was fairly empty when it first loaded.   Adding a ‘step’ allowed me to specify what packages I wanted to grab for the deployment. This part requires a NuGet package feed to be set up, which is where Deployment Manager will look for the packages. At Red Gate, we already have one set up, so I just needed to tell Deployment Manager about it. Don’t worry; there is a nice guide included on how to go about doing all of this on the ‘Package Feeds’ page in ‘Settings’, if you need any help with setting these bits up.    At Red Gate we use a build server, TeamCity, which is capable of publishing built projects to the NuGet feed we use. This makes the workflow for Format SQL relatively simple: when I commit a change to the project, the build server is configured to grab those changes, build the project, and spit out a new NuGet package to the Red Gate NuGet package feed. My ‘package step’, therefore, is set up to look for this package on our feed. The final part of package step was simply specifying which machines from what environments I wanted to be able to deploy the project to.     Format SQL Now the main Dashboard showed my new project and environment in a rather empty looking grid. Clicking on my project presented me with a nice little message telling me that I am now ready to create my first release!   Create a release Next I clicked on the ‘Create release’ button in the Projects tab. If your feeds and package step(s) were set up correctly, then Deployment Manager will automatically grab the latest version of the NuGet package that you want to deploy. As you can see here, it was able to pick up the latest build for Format SQL and all I needed to do was enter a version number and description of the release.   As you can see underneath ‘Version number’, it keeps track of what version the previous release was given. Clicking ‘Create’ created the release and redirected me to a summary of it where I could check the details before deploying.   I clicked ‘Deploy this release’ and chose the environment I wanted to deploy to and…that’s it. Deployment Manager went off and deployed it for me.   Once I clicked ‘Deploy release’, Deployment Manager started to automatically update and provide continuing feedback about the process. If any errors do arise, then I can expand the results to see where it went wrong. That’s it, I’m done! Keep in mind, if you hit errors with the deployment itself then it is possible to view the log output to try and determine where these occurred. You can keep expanding the logs to narrow down the problem. The screenshot below is not from my Format SQL deployment, but I thought I’d post one to demonstrate the logging output available. Features One of the best bits of Deployment Manager for me is the ability to very, very easily deploy the same release to multiple machines. Deploying this same release to production was just a case of selecting the deployment and choosing the ‘live’ environment as the place to deploy to. Following on from this is the fact that, as Deployment Manager keeps track of all of your releases, it is extremely easy to roll back to a previous release if anything goes pear-shaped! You can view all your previous releases and select one to re-deploy. I needed this feature more than once when differences in my production and staging machines lead to some odd behavior.     Another option is to use the TeamCity integration available. This enables you to set Deployment Manager up so that it will automatically create releases and deploy these to an environment directly from TeamCity, meaning that you can always see the latest version up and running without having to do anything. Machine Specific Deployments ‘What about custom configuration files?’ I hear you shout. Certainly, it was one of my concerns. Our setup on the staging machine is not in line with that on production. What this means is that, should we deploy the same configuration to both, one of them is going to break. Thankfully, it turns out that Deployment Manager can deal with this. Given I had environments ‘staging’ and ‘live’, and that staging used the project’s web.config file, while production (‘live’) required the config file to undergo some transformations, I simply added a web.live.config file in the project, so that it would be included as part of the NuGet package. In this file, I wrote the XML document transformations I needed and Deployment Manager took care of the rest. Another option is to set up ‘variables’ for your project, which allow you to specify key-value pairs for your configuration file, and which environment to apply them to. You’ll find Variables as a full left-hand submenu within the ‘Projects’ tab. These features will definitely be of interest if you have a large number of environments! There are still many other features that I didn’t get a chance to play around with like running PowerShell scripts for more personalised deployments. Maybe next time! Also, let’s not forget that my use case in this article is a very simple one – deploying a single package. I don’t believe that all projects will be equally as simple, but I already appreciate how much easier Deployment Manager could make my life. I look forward to the possibility of moving our other sites over to Deployment Manager in the near future.   Conclusion In this article I have described the steps involved in setting up and configuring an instance of Deployment Manager, creating a new automated deployment process, and using this to actually carry out a deployment. I’ve tried to mention some of the features I found particularly useful, such as error logging, easy release management allowing you to deploy the same release multiple times, and configuration file transformations. If I had to point out one issue, then it would be that the releases are immutable, which from a development point of view makes sense. However, this causes confusion where I have to create a new release to deploy to a newly set up environment – I cannot simply deploy an old release onto a new environment, the whole release needs to be recreated. I really liked how easy it was to get going with the product. Setting up Format SQL and making a first deployment took very little time. Especially when you compare it to how long it takes me to manually deploy the other site, as I described earlier. I liked how it let me know what I needed to do next, with little messages flagging up that I needed to ‘create environments’ or ‘add some deployment steps’ before I could continue. I found the dashboard incredibly convenient. As the number of projects and environments increase, it might become awkward to try and search them and find out what state they are in. Instead, the dashboard handily keeps track of the latest deployments of each project and lets you know what version is running on each of the environments, and when that deployment occurred. Finally, do you remember my complaint about having to rename folders so that I could keep track of what build they came from? This is yet another thing that Deployment Manager takes care of for you. Each release is put into its own directory, which takes the name of whatever version number that release has, though these can be customised if necessary. If you’d like to take a look at Deployment Manager for yourself, then you can download it here.

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  • Why should main() be short?

    - by Stargazer712
    I've been programming for over 9 years, and according to the advice of my first programming teacher, I always keep my main() function extremely short. At first I had no idea why. I just obeyed without understanding, much to the delight of my professors. After gaining experience, I realized that if I designed my code correctly, having a short main() function just sortof happened. Writing modularized code and following the single responsibility principle allowed my code to be designed in "bunches", and main() served as nothing more than a catalyst to get the program running. Fast forward to a few weeks ago, I was looking at Python's souce code, and I found the main() function: /* Minimal main program -- everything is loaded from the library */ ... int main(int argc, char **argv) { ... return Py_Main(argc, argv); } Yay python. Short main() function == Good code. Programming teachers were right. Wanting to look deeper, I took a look at Py_Main. In its entirety, it is defined as follows: /* Main program */ int Py_Main(int argc, char **argv) { int c; int sts; char *command = NULL; char *filename = NULL; char *module = NULL; FILE *fp = stdin; char *p; int unbuffered = 0; int skipfirstline = 0; int stdin_is_interactive = 0; int help = 0; int version = 0; int saw_unbuffered_flag = 0; PyCompilerFlags cf; cf.cf_flags = 0; orig_argc = argc; /* For Py_GetArgcArgv() */ orig_argv = argv; #ifdef RISCOS Py_RISCOSWimpFlag = 0; #endif PySys_ResetWarnOptions(); while ((c = _PyOS_GetOpt(argc, argv, PROGRAM_OPTS)) != EOF) { if (c == 'c') { /* -c is the last option; following arguments that look like options are left for the command to interpret. */ command = (char *)malloc(strlen(_PyOS_optarg) + 2); if (command == NULL) Py_FatalError( "not enough memory to copy -c argument"); strcpy(command, _PyOS_optarg); strcat(command, "\n"); break; } if (c == 'm') { /* -m is the last option; following arguments that look like options are left for the module to interpret. */ module = (char *)malloc(strlen(_PyOS_optarg) + 2); if (module == NULL) Py_FatalError( "not enough memory to copy -m argument"); strcpy(module, _PyOS_optarg); break; } switch (c) { case 'b': Py_BytesWarningFlag++; break; case 'd': Py_DebugFlag++; break; case '3': Py_Py3kWarningFlag++; if (!Py_DivisionWarningFlag) Py_DivisionWarningFlag = 1; break; case 'Q': if (strcmp(_PyOS_optarg, "old") == 0) { Py_DivisionWarningFlag = 0; break; } if (strcmp(_PyOS_optarg, "warn") == 0) { Py_DivisionWarningFlag = 1; break; } if (strcmp(_PyOS_optarg, "warnall") == 0) { Py_DivisionWarningFlag = 2; break; } if (strcmp(_PyOS_optarg, "new") == 0) { /* This only affects __main__ */ cf.cf_flags |= CO_FUTURE_DIVISION; /* And this tells the eval loop to treat BINARY_DIVIDE as BINARY_TRUE_DIVIDE */ _Py_QnewFlag = 1; break; } fprintf(stderr, "-Q option should be `-Qold', " "`-Qwarn', `-Qwarnall', or `-Qnew' only\n"); return usage(2, argv[0]); /* NOTREACHED */ case 'i': Py_InspectFlag++; Py_InteractiveFlag++; break; /* case 'J': reserved for Jython */ case 'O': Py_OptimizeFlag++; break; case 'B': Py_DontWriteBytecodeFlag++; break; case 's': Py_NoUserSiteDirectory++; break; case 'S': Py_NoSiteFlag++; break; case 'E': Py_IgnoreEnvironmentFlag++; break; case 't': Py_TabcheckFlag++; break; case 'u': unbuffered++; saw_unbuffered_flag = 1; break; case 'v': Py_VerboseFlag++; break; #ifdef RISCOS case 'w': Py_RISCOSWimpFlag = 1; break; #endif case 'x': skipfirstline = 1; break; /* case 'X': reserved for implementation-specific arguments */ case 'U': Py_UnicodeFlag++; break; case 'h': case '?': help++; break; case 'V': version++; break; case 'W': PySys_AddWarnOption(_PyOS_optarg); break; /* This space reserved for other options */ default: return usage(2, argv[0]); /*NOTREACHED*/ } } if (help) return usage(0, argv[0]); if (version) { fprintf(stderr, "Python %s\n", PY_VERSION); return 0; } if (Py_Py3kWarningFlag && !Py_TabcheckFlag) /* -3 implies -t (but not -tt) */ Py_TabcheckFlag = 1; if (!Py_InspectFlag && (p = Py_GETENV("PYTHONINSPECT")) && *p != '\0') Py_InspectFlag = 1; if (!saw_unbuffered_flag && (p = Py_GETENV("PYTHONUNBUFFERED")) && *p != '\0') unbuffered = 1; if (!Py_NoUserSiteDirectory && (p = Py_GETENV("PYTHONNOUSERSITE")) && *p != '\0') Py_NoUserSiteDirectory = 1; if ((p = Py_GETENV("PYTHONWARNINGS")) && *p != '\0') { char *buf, *warning; buf = (char *)malloc(strlen(p) + 1); if (buf == NULL) Py_FatalError( "not enough memory to copy PYTHONWARNINGS"); strcpy(buf, p); for (warning = strtok(buf, ","); warning != NULL; warning = strtok(NULL, ",")) PySys_AddWarnOption(warning); free(buf); } if (command == NULL && module == NULL && _PyOS_optind < argc && strcmp(argv[_PyOS_optind], "-") != 0) { #ifdef __VMS filename = decc$translate_vms(argv[_PyOS_optind]); if (filename == (char *)0 || filename == (char *)-1) filename = argv[_PyOS_optind]; #else filename = argv[_PyOS_optind]; #endif } stdin_is_interactive = Py_FdIsInteractive(stdin, (char *)0); if (unbuffered) { #if defined(MS_WINDOWS) || defined(__CYGWIN__) _setmode(fileno(stdin), O_BINARY); _setmode(fileno(stdout), O_BINARY); #endif #ifdef HAVE_SETVBUF setvbuf(stdin, (char *)NULL, _IONBF, BUFSIZ); setvbuf(stdout, (char *)NULL, _IONBF, BUFSIZ); setvbuf(stderr, (char *)NULL, _IONBF, BUFSIZ); #else /* !HAVE_SETVBUF */ setbuf(stdin, (char *)NULL); setbuf(stdout, (char *)NULL); setbuf(stderr, (char *)NULL); #endif /* !HAVE_SETVBUF */ } else if (Py_InteractiveFlag) { #ifdef MS_WINDOWS /* Doesn't have to have line-buffered -- use unbuffered */ /* Any set[v]buf(stdin, ...) screws up Tkinter :-( */ setvbuf(stdout, (char *)NULL, _IONBF, BUFSIZ); #else /* !MS_WINDOWS */ #ifdef HAVE_SETVBUF setvbuf(stdin, (char *)NULL, _IOLBF, BUFSIZ); setvbuf(stdout, (char *)NULL, _IOLBF, BUFSIZ); #endif /* HAVE_SETVBUF */ #endif /* !MS_WINDOWS */ /* Leave stderr alone - it should be unbuffered anyway. */ } #ifdef __VMS else { setvbuf (stdout, (char *)NULL, _IOLBF, BUFSIZ); } #endif /* __VMS */ #ifdef __APPLE__ /* On MacOS X, when the Python interpreter is embedded in an application bundle, it gets executed by a bootstrapping script that does os.execve() with an argv[0] that's different from the actual Python executable. This is needed to keep the Finder happy, or rather, to work around Apple's overly strict requirements of the process name. However, we still need a usable sys.executable, so the actual executable path is passed in an environment variable. See Lib/plat-mac/bundlebuiler.py for details about the bootstrap script. */ if ((p = Py_GETENV("PYTHONEXECUTABLE")) && *p != '\0') Py_SetProgramName(p); else Py_SetProgramName(argv[0]); #else Py_SetProgramName(argv[0]); #endif Py_Initialize(); if (Py_VerboseFlag || (command == NULL && filename == NULL && module == NULL && stdin_is_interactive)) { fprintf(stderr, "Python %s on %s\n", Py_GetVersion(), Py_GetPlatform()); if (!Py_NoSiteFlag) fprintf(stderr, "%s\n", COPYRIGHT); } if (command != NULL) { /* Backup _PyOS_optind and force sys.argv[0] = '-c' */ _PyOS_optind--; argv[_PyOS_optind] = "-c"; } if (module != NULL) { /* Backup _PyOS_optind and force sys.argv[0] = '-c' so that PySys_SetArgv correctly sets sys.path[0] to '' rather than looking for a file called "-m". See tracker issue #8202 for details. */ _PyOS_optind--; argv[_PyOS_optind] = "-c"; } PySys_SetArgv(argc-_PyOS_optind, argv+_PyOS_optind); if ((Py_InspectFlag || (command == NULL && filename == NULL && module == NULL)) && isatty(fileno(stdin))) { PyObject *v; v = PyImport_ImportModule("readline"); if (v == NULL) PyErr_Clear(); else Py_DECREF(v); } if (command) { sts = PyRun_SimpleStringFlags(command, &cf) != 0; free(command); } else if (module) { sts = RunModule(module, 1); free(module); } else { if (filename == NULL && stdin_is_interactive) { Py_InspectFlag = 0; /* do exit on SystemExit */ RunStartupFile(&cf); } /* XXX */ sts = -1; /* keep track of whether we've already run __main__ */ if (filename != NULL) { sts = RunMainFromImporter(filename); } if (sts==-1 && filename!=NULL) { if ((fp = fopen(filename, "r")) == NULL) { fprintf(stderr, "%s: can't open file '%s': [Errno %d] %s\n", argv[0], filename, errno, strerror(errno)); return 2; } else if (skipfirstline) { int ch; /* Push back first newline so line numbers remain the same */ while ((ch = getc(fp)) != EOF) { if (ch == '\n') { (void)ungetc(ch, fp); break; } } } { /* XXX: does this work on Win/Win64? (see posix_fstat) */ struct stat sb; if (fstat(fileno(fp), &sb) == 0 && S_ISDIR(sb.st_mode)) { fprintf(stderr, "%s: '%s' is a directory, cannot continue\n", argv[0], filename); fclose(fp); return 1; } } } if (sts==-1) { /* call pending calls like signal handlers (SIGINT) */ if (Py_MakePendingCalls() == -1) { PyErr_Print(); sts = 1; } else { sts = PyRun_AnyFileExFlags( fp, filename == NULL ? "<stdin>" : filename, filename != NULL, &cf) != 0; } } } /* Check this environment variable at the end, to give programs the * opportunity to set it from Python. */ if (!Py_InspectFlag && (p = Py_GETENV("PYTHONINSPECT")) && *p != '\0') { Py_InspectFlag = 1; } if (Py_InspectFlag && stdin_is_interactive && (filename != NULL || command != NULL || module != NULL)) { Py_InspectFlag = 0; /* XXX */ sts = PyRun_AnyFileFlags(stdin, "<stdin>", &cf) != 0; } Py_Finalize(); #ifdef RISCOS if (Py_RISCOSWimpFlag) fprintf(stderr, "\x0cq\x0c"); /* make frontend quit */ #endif #ifdef __INSURE__ /* Insure++ is a memory analysis tool that aids in discovering * memory leaks and other memory problems. On Python exit, the * interned string dictionary is flagged as being in use at exit * (which it is). Under normal circumstances, this is fine because * the memory will be automatically reclaimed by the system. Under * memory debugging, it's a huge source of useless noise, so we * trade off slower shutdown for less distraction in the memory * reports. -baw */ _Py_ReleaseInternedStrings(); #endif /* __INSURE__ */ return sts; } Good God Almighty...it is big enough to sink the Titanic. It seems as though Python did the "Intro to Programming 101" trick and just moved all of main()'s code to a different function called it something very similar to "main". Here's my question: Is this code terribly written, or are there other reasons to have a short main function? As it stands right now, I see absolutely no difference between doing this and just moving the code in Py_Main() back into main(). Am I wrong in thinking this?

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  • PASS: Bylaw Change 2013

    - by Bill Graziano
    PASS launched a Global Growth Initiative in the Summer of 2011 with the appointment of three international Board advisors.  Since then we’ve thought and talked extensively about how we make PASS more relevant to our members outside the US and Canada.  We’ve collected much of that discussion in our Global Growth site.  You can find vision documents, plans, governance proposals, feedback sites, and transcripts of Twitter chats and town hall meetings.  We also address these plans at the Board Q&A during the 2012 Summit. One of the biggest changes coming out of this process is around how we elect Board members.  And that requires a change to the bylaws.  We published the proposed bylaw changes as a red-lined document so you can clearly see the changes.  Our goal in these bylaw changes was to address the changes required by the global growth initiatives, conduct a legal review of the document and address other minor issues in the document.  There are numerous small wording changes throughout the document.  For example, we replaced every reference of “The Corporation” with the word “PASS” so it now reads “PASS is organized…”. Board Composition The biggest change in these bylaw changes is how the Board is composed and elected.  This discussion starts in section VI.2.  This section now says that some elected directors will come from geographic regions.  I think this is the best way to make sure we give all of our members a voice in the leadership of the organization.  The key parts of this section are: The remaining Directors (i.e. the non-Officer Directors and non-Vendor Appointed Directors) shall be elected by the voting membership (“Elected Directors”). Elected Directors shall include representatives of defined PASS regions (“Regions”) as set forth below (“Regional Directors”) and at minimum one (1) additional Director-at-Large whose selection is not limited by region. Regional Directors shall include, but are not limited to, two (2) seats for the Region covering Canada and the United States of America. Additional Regions for the purpose of electing additional Regional Directors and additional Director-at-Large seats for the purpose of expanding the Board shall be defined by a majority vote of the current Board of Directors and must be established prior to the public call for nominations in the general election. Previously defined Regions and seats approved by the Board of Directors shall remain in effect and can only be modified by a 2/3 majority vote by the then current Board of Directors. Currently PASS has six At-Large Directors elected by the members.  These changes allow for a Regional Director position that is elected by the members but must come from a particular region.  It also stipulates that there must always be at least one Director-at-Large who can come from any region. We also understand that PASS is currently a very US-centric organization.  Our Summit is held in America, roughly half our chapters are in the US and Canada and most of the Board members over the last ten years have come from America.  We wanted to reflect that by making sure that our US and Canadian volunteers would continue to play a significant role by ensuring that two Regional seats are reserved specifically for Canada and the US. Other than that, the bylaws don’t create any specific regional seats.  These rules allow us to create Regional Director seats but don’t require it.  We haven’t fully discussed what the criteria will be in order for a region to have a seat designated for it or how many regions there will be.  In our discussions we’ve broadly discussed regions for United States and Canada Europe, Middle East, and Africa (EMEA) Australia, New Zealand and Asia (also known as Asia Pacific or APAC) Mexico, South America, and Central America (LATAM) As you can see, our thinking is that there will be a few large regions.  I’ve also considered a non-North America region that we can gradually split into the regions above as our membership grows in those areas.  The regions will be defined by a policy document that will be published prior to the elections. I’m hoping that over the next year we can begin to publish more of what we do as Board-approved policy documents. While the bylaws only require a single non-region specific At-large Director, I would expect we would always have two.  That way we can have one in each election.  I think it’s important that we always have one seat open that anyone who is eligible to run for the Board can contest.  The Board is required to have any regions defined prior to the start of the election process. Board Elections – Regional Seats We spent a lot of time discussing how the elections would work for these Regional Director seats.  Ultimately we decided that the simplest solution is that every PASS member should vote for every open seat.  Section VIII.3 reads: Candidates who are eligible (i.e. eligible to serve in such capacity subject to the criteria set forth herein or adopted by the Board of Directors) shall be designated to fill open Board seats in the following order of priority on the basis of total votes received: (i) full term Regional Director seats, (ii) full term Director-at-Large seats, (iii) not full term (vacated) Regional Director seats, (iv) not full term (vacated) Director-at-Large seats. For the purposes of clarity, because of eligibility requirements, it is contemplated that the candidates designated to the open Board seats may not receive more votes than certain other candidates who are not selected to the Board. We debated whether to have multiple ballots or one single ballot.  Multiple ballot elections get complicated quickly.  Let’s say we have a ballot for US/Canada and one for Region 2.  After that we’d need a mechanism to merge those two together and come up with the winner of the at-large seat or have another election for the at-large position.  We think the best way to do this is a single ballot and putting the highest vote getters into the most restrictive seats.  Let’s look at an example: There are seats open for Region 1, Region 2 and at-large.  The election results are as follows: Candidate A (eligible for Region 1) – 550 votes Candidate B (eligible for Region 1) – 525 votes Candidate C (eligible for Region 1) – 475 votes Candidate D (eligible for Region 2) – 125 votes Candidate E (eligible for Region 2) – 75 votes In this case, Candidate A is the winner for Region 1 and is assigned that seat.  Candidate D is the winner for Region 2 and is assigned that seat.  The at-large seat is filled by the high remaining vote getter which is Candidate B. The key point to understand is that we may have a situation where a person with a lower vote total is elected to a regional seat and a person with a higher vote total is excluded.  This will be true whether we had multiple ballots or a single ballot.  Board Elections – Vacant Seats The other change to the election process is for vacant Board seats.  The actual changes are sprinkled throughout the document. Previously we didn’t have a mechanism that allowed for an election of a Board seat that we knew would be vacant in the future.  The most common case is when a Board members moves to an Officer role in the middle of their term.  One of the key changes is to allow the number of votes members have to match the number of open seats.  This allows each voter to express their preference on all open seats.  This only applies when we know about the opening prior to the call for nominations.  This all means that if there’s a seat will be open at the start of the next Board term, and we know about it prior to the call for nominations, we can include that seat in the elections.  Ultimately, the aim is to have PASS members decide who sits on the Board in as many situations as possible. We discussed the option of changing the bylaws to just take next highest vote-getter in all other cases.  I think that’s wrong for the following reasons: All voters aren’t able to express an opinion on all candidates.  If there are five people running for three seats, you can only vote for three.  You have no way to express your preference between #4 and #5. Different candidates may have different information about the number of seats available.  A person may learn that a Board member plans to resign at the end of the year prior to that information being made public. They may understand that the top four vote getters will end up on the Board while the rest of the members believe there are only three openings.  This may affect someone’s decision to run.  I don’t think this creates a transparent, fair election. Board members may use their knowledge of the election results to decide whether to remain on the Board or not.  Admittedly this one is unlikely but I don’t want to create a situation where this accusation can be leveled. I think the majority of vacancies in the future will be handled through elections.  The bylaw section quoted above also indicates that partial term vacancies will be filled after the full term seats are filled. Removing Directors Section VI.7 on removing directors has always had a clause that allowed members to remove an elected director.  We also had a clause that allowed appointed directors to be removed.  We added a clause that allows the Board to remove for cause any director with a 2/3 majority vote.  The updated text reads: Any Director may be removed for cause by a 2/3 majority vote of the Board of Directors whenever in its judgment the best interests of PASS would be served thereby. Notwithstanding the foregoing, the authority of any Director to act as in an official capacity as a Director or Officer of PASS may be suspended by the Board of Directors for cause. Cause for suspension or removal of a Director shall include but not be limited to failure to meet any Board-approved performance expectations or the presence of a reason for suspension or dismissal as listed in Addendum B of these Bylaws. The first paragraph is updated and the second and third are unchanged (except cleaning up language).  If you scroll down and look at Addendum B of these bylaws you find the following: Cause for suspension or dismissal of a member of the Board of Directors may include: Inability to attend Board meetings on a regular basis. Inability or unwillingness to act in a capacity designated by the Board of Directors. Failure to fulfill the responsibilities of the office. Inability to represent the Region elected to represent Failure to act in a manner consistent with PASS's Bylaws and/or policies. Misrepresentation of responsibility and/or authority. Misrepresentation of PASS. Unresolved conflict of interests with Board responsibilities. Breach of confidentiality. The bold line about your inability to represent your region is what we added to the bylaws in this revision.  We also added a clause to section VII.3 allowing the Board to remove an officer.  That clause is much less restrictive.  It doesn’t require cause and only requires a simple majority. The Board of Directors may remove any Officer whenever in their judgment the best interests of PASS shall be served by such removal. Other There are numerous other small changes throughout the document. Proxy voting.  The laws around how members and Board members proxy votes are specific in Illinois law.  PASS is an Illinois corporation and is subject to Illinois laws.  We changed section IV.5 to come into compliance with those laws.  Specifically this says you can only vote through a proxy if you have a written proxy through your authorized attorney.  English language proficiency.  As we increase our global footprint we come across more members that aren’t native English speakers.  The business of PASS is conducted in English and it’s important that our Board members speak English.  If we get big enough to afford translators, we may be able to relax this but right now we need English language skills for effective Board members. Committees.  The language around committees in section IX is old and dated.  Our lawyers advised us to clean it up.  This section specifically applies to any committees that the Board may form outside of portfolios.  We removed the term limits, quorum and vacancies clause.  We don’t currently have any committees that this would apply to.  The Nominating Committee is covered elsewhere in the bylaws. Electronic Votes.  The change allows the Board to vote via email but the results must be unanimous.  This is to conform with Illinois state law. Immediate Past President.  There was no mechanism to fill the IPP role if an outgoing President chose not to participate.  We changed section VII.8 to allow the Board to invite any previous President to fill the role by majority vote. Nominations Committee.  We’ve opened the language to allow for the transparent election of the Nominations Committee as outlined by the 2011 Election Review Committee. Revocation of Charters. The language surrounding the revocation of charters for local groups was flagged by the lawyers. We have allowed for the local user group to make all necessary payment before considering returning of items to PASS if required. Bylaw notification. We’ve spent countless meetings working on these bylaws with the intent to not open them again any time in the near future. Should the bylaws be opened again, we have included a clause ensuring that the PASS membership is involved. I’m proud that the Board has remained committed to transparency and accountability to members. This clause will require that same level of commitment in the future even when all the current Board members have rolled off. I think that covers everything.  I’d encourage you to look through the red-line document and see the changes.  It’s helpful to look at the language that’s being removed and the language that’s being added.  I’m happy to answer any questions here or you can email them to [email protected].

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  • C#/.NET Little Wonders: Interlocked CompareExchange()

    - by James Michael Hare
    Once again, in this series of posts I look at the parts of the .NET Framework that may seem trivial, but can help improve your code by making it easier to write and maintain. The index of all my past little wonders posts can be found here. Two posts ago, I discussed the Interlocked Add(), Increment(), and Decrement() methods (here) for adding and subtracting values in a thread-safe, lightweight manner.  Then, last post I talked about the Interlocked Read() and Exchange() methods (here) for safely and efficiently reading and setting 32 or 64 bit values (or references).  This week, we’ll round out the discussion by talking about the Interlocked CompareExchange() method and how it can be put to use to exchange a value if the current value is what you expected it to be. Dirty reads can lead to bad results Many of the uses of Interlocked that we’ve explored so far have centered around either reading, setting, or adding values.  But what happens if you want to do something more complex such as setting a value based on the previous value in some manner? Perhaps you were creating an application that reads a current balance, applies a deposit, and then saves the new modified balance, where of course you’d want that to happen atomically.  If you read the balance, then go to save the new balance and between that time the previous balance has already changed, you’ll have an issue!  Think about it, if we read the current balance as $400, and we are applying a new deposit of $50.75, but meanwhile someone else deposits $200 and sets the total to $600, but then we write a total of $450.75 we’ve lost $200! Now, certainly for int and long values we can use Interlocked.Add() to handles these cases, and it works well for that.  But what if we want to work with doubles, for example?  Let’s say we wanted to add the numbers from 0 to 99,999 in parallel.  We could do this by spawning several parallel tasks to continuously add to a total: 1: double total = 0; 2:  3: Parallel.For(0, 10000, next => 4: { 5: total += next; 6: }); Were this run on one thread using a standard for loop, we’d expect an answer of 4,999,950,000 (the sum of all numbers from 0 to 99,999).  But when we run this in parallel as written above, we’ll likely get something far off.  The result of one of my runs, for example, was 1,281,880,740.  That is way off!  If this were banking software we’d be in big trouble with our clients.  So what happened?  The += operator is not atomic, it will read in the current value, add the result, then store it back into the total.  At any point in all of this another thread could read a “dirty” current total and accidentally “skip” our add.   So, to clean this up, we could use a lock to guarantee concurrency: 1: double total = 0.0; 2: object locker = new object(); 3:  4: Parallel.For(0, count, next => 5: { 6: lock (locker) 7: { 8: total += next; 9: } 10: }); Which will give us the correct result of 4,999,950,000.  One thing to note is that locking can be heavy, especially if the operation being locked over is trivial, or the life of the lock is a high percentage of the work being performed concurrently.  In the case above, the lock consumes pretty much all of the time of each parallel task – and the task being locked on is relatively trivial. Now, let me put in a disclaimer here before we go further: For most uses, lock is more than sufficient for your needs, and is often the simplest solution!    So, if lock is sufficient for most needs, why would we ever consider another solution?  The problem with locking is that it can suspend execution of your thread while it waits for the signal that the lock is free.  Moreover, if the operation being locked over is trivial, the lock can add a very high level of overhead.  This is why things like Interlocked.Increment() perform so well, instead of locking just to perform an increment, we perform the increment with an atomic, lockless method. As with all things performance related, it’s important to profile before jumping to the conclusion that you should optimize everything in your path.  If your profiling shows that locking is causing a high level of waiting in your application, then it’s time to consider lighter alternatives such as Interlocked. CompareExchange() – Exchange existing value if equal some value So let’s look at how we could use CompareExchange() to solve our problem above.  The general syntax of CompareExchange() is: T CompareExchange<T>(ref T location, T newValue, T expectedValue) If the value in location == expectedValue, then newValue is exchanged.  Either way, the value in location (before exchange) is returned. Actually, CompareExchange() is not one method, but a family of overloaded methods that can take int, long, float, double, pointers, or references.  It cannot take other value types (that is, can’t CompareExchange() two DateTime instances directly).  Also keep in mind that the version that takes any reference type (the generic overload) only checks for reference equality, it does not call any overridden Equals(). So how does this help us?  Well, we can grab the current total, and exchange the new value if total hasn’t changed.  This would look like this: 1: // grab the snapshot 2: double current = total; 3:  4: // if the total hasn’t changed since I grabbed the snapshot, then 5: // set it to the new total 6: Interlocked.CompareExchange(ref total, current + next, current); So what the code above says is: if the amount in total (1st arg) is the same as the amount in current (3rd arg), then set total to current + next (2nd arg).  This check and exchange pair is atomic (and thus thread-safe). This works if total is the same as our snapshot in current, but the problem, is what happens if they aren’t the same?  Well, we know that in either case we will get the previous value of total (before the exchange), back as a result.  Thus, we can test this against our snapshot to see if it was the value we expected: 1: // if the value returned is != current, then our snapshot must be out of date 2: // which means we didn't (and shouldn't) apply current + next 3: if (Interlocked.CompareExchange(ref total, current + next, current) != current) 4: { 5: // ooops, total was not equal to our snapshot in current, what should we do??? 6: } So what do we do if we fail?  That’s up to you and the problem you are trying to solve.  It’s possible you would decide to abort the whole transaction, or perhaps do a lightweight spin and try again.  Let’s try that: 1: double current = total; 2:  3: // make first attempt... 4: if (Interlocked.CompareExchange(ref total, current + i, current) != current) 5: { 6: // if we fail, go into a spin wait, spin, and try again until succeed 7: var spinner = new SpinWait(); 8:  9: do 10: { 11: spinner.SpinOnce(); 12: current = total; 13: } 14: while (Interlocked.CompareExchange(ref total, current + i, current) != current); 15: } 16:  This is not trivial code, but it illustrates a possible use of CompareExchange().  What we are doing is first checking to see if we succeed on the first try, and if so great!  If not, we create a SpinWait and then repeat the process of SpinOnce(), grab a fresh snapshot, and repeat until CompareExchnage() succeeds.  You may wonder why not a simple do-while here, and the reason it’s more efficient to only create the SpinWait until we absolutely know we need one, for optimal efficiency. Though not as simple (or maintainable) as a simple lock, this will perform better in many situations.  Comparing an unlocked (and wrong) version, a version using lock, and the Interlocked of the code, we get the following average times for multiple iterations of adding the sum of 100,000 numbers: 1: Unlocked money average time: 2.1 ms 2: Locked money average time: 5.1 ms 3: Interlocked money average time: 3 ms So the Interlocked.CompareExchange(), while heavier to code, came in lighter than the lock, offering a good compromise of safety and performance when we need to reduce contention. CompareExchange() - it’s not just for adding stuff… So that was one simple use of CompareExchange() in the context of adding double values -- which meant we couldn’t have used the simpler Interlocked.Add() -- but it has other uses as well. If you think about it, this really works anytime you want to create something new based on a current value without using a full lock.  For example, you could use it to create a simple lazy instantiation implementation.  In this case, we want to set the lazy instance only if the previous value was null: 1: public static class Lazy<T> where T : class, new() 2: { 3: private static T _instance; 4:  5: public static T Instance 6: { 7: get 8: { 9: // if current is null, we need to create new instance 10: if (_instance == null) 11: { 12: // attempt create, it will only set if previous was null 13: Interlocked.CompareExchange(ref _instance, new T(), (T)null); 14: } 15:  16: return _instance; 17: } 18: } 19: } So, if _instance == null, this will create a new T() and attempt to exchange it with _instance.  If _instance is not null, then it does nothing and we discard the new T() we created. This is a way to create lazy instances of a type where we are more concerned about locking overhead than creating an accidental duplicate which is not used.  In fact, the BCL implementation of Lazy<T> offers a similar thread-safety choice for Publication thread safety, where it will not guarantee only one instance was created, but it will guarantee that all readers get the same instance.  Another possible use would be in concurrent collections.  Let’s say, for example, that you are creating your own brand new super stack that uses a linked list paradigm and is “lock free”.  We could use Interlocked.CompareExchange() to be able to do a lockless Push() which could be more efficient in multi-threaded applications where several threads are pushing and popping on the stack concurrently. Yes, there are already concurrent collections in the BCL (in .NET 4.0 as part of the TPL), but it’s a fun exercise!  So let’s assume we have a node like this: 1: public sealed class Node<T> 2: { 3: // the data for this node 4: public T Data { get; set; } 5:  6: // the link to the next instance 7: internal Node<T> Next { get; set; } 8: } Then, perhaps, our stack’s Push() operation might look something like: 1: public sealed class SuperStack<T> 2: { 3: private volatile T _head; 4:  5: public void Push(T value) 6: { 7: var newNode = new Node<int> { Data = value, Next = _head }; 8:  9: if (Interlocked.CompareExchange(ref _head, newNode, newNode.Next) != newNode.Next) 10: { 11: var spinner = new SpinWait(); 12:  13: do 14: { 15: spinner.SpinOnce(); 16: newNode.Next = _head; 17: } 18: while (Interlocked.CompareExchange(ref _head, newNode, newNode.Next) != newNode.Next); 19: } 20: } 21:  22: // ... 23: } Notice a similar paradigm here as with adding our doubles before.  What we are doing is creating the new Node with the data to push, and with a Next value being the original node referenced by _head.  This will create our stack behavior (LIFO – Last In, First Out).  Now, we have to set _head to now refer to the newNode, but we must first make sure it hasn’t changed! So we check to see if _head has the same value we saved in our snapshot as newNode.Next, and if so, we set _head to newNode.  This is all done atomically, and the result is _head’s original value, as long as the original value was what we assumed it was with newNode.Next, then we are good and we set it without a lock!  If not, we SpinWait and try again. Once again, this is much lighter than locking in highly parallelized code with lots of contention.  If I compare the method above with a similar class using lock, I get the following results for pushing 100,000 items: 1: Locked SuperStack average time: 6 ms 2: Interlocked SuperStack average time: 4.5 ms So, once again, we can get more efficient than a lock, though there is the cost of added code complexity.  Fortunately for you, most of the concurrent collection you’d ever need are already created for you in the System.Collections.Concurrent (here) namespace – for more information, see my Little Wonders – The Concurent Collections Part 1 (here), Part 2 (here), and Part 3 (here). Summary We’ve seen before how the Interlocked class can be used to safely and efficiently add, increment, decrement, read, and exchange values in a multi-threaded environment.  In addition to these, Interlocked CompareExchange() can be used to perform more complex logic without the need of a lock when lock contention is a concern. The added efficiency, though, comes at the cost of more complex code.  As such, the standard lock is often sufficient for most thread-safety needs.  But if profiling indicates you spend a lot of time waiting for locks, or if you just need a lock for something simple such as an increment, decrement, read, exchange, etc., then consider using the Interlocked class’s methods to reduce wait. Technorati Tags: C#,CSharp,.NET,Little Wonders,Interlocked,CompareExchange,threading,concurrency

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  • Dynamic JSON Parsing in .NET with JsonValue

    - by Rick Strahl
    So System.Json has been around for a while in Silverlight, but it's relatively new for the desktop .NET framework and now moving into the lime-light with the pending release of ASP.NET Web API which is bringing a ton of attention to server side JSON usage. The JsonValue, JsonObject and JsonArray objects are going to be pretty useful for Web API applications as they allow you dynamically create and parse JSON values without explicit .NET types to serialize from or into. But even more so I think JsonValue et al. are going to be very useful when consuming JSON APIs from various services. Yes I know C# is strongly typed, why in the world would you want to use dynamic values? So many times I've needed to retrieve a small morsel of information from a large service JSON response and rather than having to map the entire type structure of what that service returns, JsonValue actually allows me to cherry pick and only work with the values I'm interested in, without having to explicitly create everything up front. With JavaScriptSerializer or DataContractJsonSerializer you always need to have a strong type to de-serialize JSON data into. Wouldn't it be nice if no explicit type was required and you could just parse the JSON directly using a very easy to use object syntax? That's exactly what JsonValue, JsonObject and JsonArray accomplish using a JSON parser and some sweet use of dynamic sauce to make it easy to access in code. Creating JSON on the fly with JsonValue Let's start with creating JSON on the fly. It's super easy to create a dynamic object structure. JsonValue uses the dynamic  keyword extensively to make it intuitive to create object structures and turn them into JSON via dynamic object syntax. Here's an example of creating a music album structure with child songs using JsonValue:[TestMethod] public void JsonValueOutputTest() { // strong type instance var jsonObject = new JsonObject(); // dynamic expando instance you can add properties to dynamic album = jsonObject; album.AlbumName = "Dirty Deeds Done Dirt Cheap"; album.Artist = "AC/DC"; album.YearReleased = 1977; album.Songs = new JsonArray() as dynamic; dynamic song = new JsonObject(); song.SongName = "Dirty Deeds Done Dirt Cheap"; song.SongLength = "4:11"; album.Songs.Add(song); song = new JsonObject(); song.SongName = "Love at First Feel"; song.SongLength = "3:10"; album.Songs.Add(song); Console.WriteLine(album.ToString()); } This produces proper JSON just as you would expect: {"AlbumName":"Dirty Deeds Done Dirt Cheap","Artist":"AC\/DC","YearReleased":1977,"Songs":[{"SongName":"Dirty Deeds Done Dirt Cheap","SongLength":"4:11"},{"SongName":"Love at First Feel","SongLength":"3:10"}]} The important thing about this code is that there's no explicitly type that is used for holding the values to serialize to JSON. I am essentially creating this value structure on the fly by adding properties and then serialize it to JSON. This means this code can be entirely driven at runtime without compile time restraints of structure for the JSON output. Here I use JsonObject() to create a new object and immediately cast it to dynamic. JsonObject() is kind of similar in behavior to ExpandoObject in that it allows you to add properties by simply assigning to them. Internally, JsonValue/JsonObject these values are stored in pseudo collections of key value pairs that are exposed as properties through the DynamicObject functionality in .NET. The syntax gets a little tedious only if you need to create child objects or arrays that have to be explicitly defined first. Other than that the syntax looks like normal object access sytnax. Always remember though these values are dynamic - which means no Intellisense and no compiler type checking. It's up to you to ensure that the values you create are accessed consistently and without typos in your code. Note that you can also access the JsonValue instance directly and get access to the underlying type. This means you can assign properties by string, which can be useful for fully data driven JSON generation from other structures. Below you can see both styles of access next to each other:// strong type instance var jsonObject = new JsonObject(); // you can explicitly add values here jsonObject.Add("Entered", DateTime.Now); // expando style instance you can just 'use' properties dynamic album = jsonObject; album.AlbumName = "Dirty Deeds Done Dirt Cheap"; JsonValue internally stores properties keys and values in collections and you can iterate over them at runtime. You can also manipulate the collections if you need to to get the object structure to look exactly like you want. Again, if you've used ExpandoObject before JsonObject/Value are very similar in the behavior of the structure. Reading JSON strings into JsonValue The JsonValue structure supports importing JSON via the Parse() and Load() methods which can read JSON data from a string or various streams respectively. Essentially JsonValue includes the core JSON parsing to turn a JSON string into a collection of JsonValue objects that can be then referenced using familiar dynamic object syntax. Here's a simple example:[TestMethod] public void JsonValueParsingTest() { var jsonString = @"{""Name"":""Rick"",""Company"":""West Wind"",""Entered"":""2012-03-16T00:03:33.245-10:00""}"; dynamic json = JsonValue.Parse(jsonString); // values require casting string name = json.Name; string company = json.Company; DateTime entered = json.Entered; Assert.AreEqual(name, "Rick"); Assert.AreEqual(company, "West Wind"); } The JSON string represents an object with three properties which is parsed into a JsonValue object and cast to dynamic. Once cast to dynamic I can then go ahead and access the object using familiar object syntax. Note that the actual values - json.Name, json.Company, json.Entered - are actually of type JsonPrimitive and I have to assign them to their appropriate types first before I can do type comparisons. The dynamic properties will automatically cast to the right type expected as long as the compiler can resolve the type of the assignment or usage. The AreEqual() method oesn't as it expects two object instances and comparing json.Company to "West Wind" is comparing two different types (JsonPrimitive to String) which fails. So the intermediary assignment is required to make the test pass. The JSON structure can be much more complex than this simple example. Here's another example of an array of albums serialized to JSON and then parsed through with JsonValue():[TestMethod] public void JsonArrayParsingTest() { var jsonString = @"[ { ""Id"": ""b3ec4e5c"", ""AlbumName"": ""Dirty Deeds Done Dirt Cheap"", ""Artist"": ""AC/DC"", ""YearReleased"": 1977, ""Entered"": ""2012-03-16T00:13:12.2810521-10:00"", ""AlbumImageUrl"": ""http://ecx.images-amazon.com/images/I/61kTaH-uZBL._AA115_.jpg"", ""AmazonUrl"": ""http://www.amazon.com/gp/product/B00008BXJ4/ref=as_li_ss_tl?ie=UTF8&tag=westwindtechn-20&linkCode=as2&camp=1789&creative=390957&creativeASIN=B00008BXJ4"", ""Songs"": [ { ""AlbumId"": ""b3ec4e5c"", ""SongName"": ""Dirty Deeds Done Dirt Cheap"", ""SongLength"": ""4:11"" }, { ""AlbumId"": ""b3ec4e5c"", ""SongName"": ""Love at First Feel"", ""SongLength"": ""3:10"" }, { ""AlbumId"": ""b3ec4e5c"", ""SongName"": ""Big Balls"", ""SongLength"": ""2:38"" } ] }, { ""Id"": ""67280fb8"", ""AlbumName"": ""Echoes, Silence, Patience & Grace"", ""Artist"": ""Foo Fighters"", ""YearReleased"": 2007, ""Entered"": ""2012-03-16T00:13:12.2810521-10:00"", ""AlbumImageUrl"": ""http://ecx.images-amazon.com/images/I/41mtlesQPVL._SL500_AA280_.jpg"", ""AmazonUrl"": ""http://www.amazon.com/gp/product/B000UFAURI/ref=as_li_ss_tl?ie=UTF8&tag=westwindtechn-20&linkCode=as2&camp=1789&creative=390957&creativeASIN=B000UFAURI"", ""Songs"": [ { ""AlbumId"": ""67280fb8"", ""SongName"": ""The Pretender"", ""SongLength"": ""4:29"" }, { ""AlbumId"": ""67280fb8"", ""SongName"": ""Let it Die"", ""SongLength"": ""4:05"" }, { ""AlbumId"": ""67280fb8"", ""SongName"": ""Erase/Replay"", ""SongLength"": ""4:13"" } ] }, { ""Id"": ""7b919432"", ""AlbumName"": ""End of the Silence"", ""Artist"": ""Henry Rollins Band"", ""YearReleased"": 1992, ""Entered"": ""2012-03-16T00:13:12.2800521-10:00"", ""AlbumImageUrl"": ""http://ecx.images-amazon.com/images/I/51FO3rb1tuL._SL160_AA160_.jpg"", ""AmazonUrl"": ""http://www.amazon.com/End-Silence-Rollins-Band/dp/B0000040OX/ref=sr_1_5?ie=UTF8&qid=1302232195&sr=8-5"", ""Songs"": [ { ""AlbumId"": ""7b919432"", ""SongName"": ""Low Self Opinion"", ""SongLength"": ""5:24"" }, { ""AlbumId"": ""7b919432"", ""SongName"": ""Grip"", ""SongLength"": ""4:51"" } ] } ]"; dynamic albums = JsonValue.Parse(jsonString); foreach (dynamic album in albums) { Console.WriteLine(album.AlbumName + " (" + album.YearReleased.ToString() + ")"); foreach (dynamic song in album.Songs) { Console.WriteLine("\t" + song.SongName ); } } Console.WriteLine(albums[0].AlbumName); Console.WriteLine(albums[0].Songs[1].SongName);}   It's pretty sweet how easy it becomes to parse even complex JSON and then just run through the object using object syntax, yet without an explicit type in the mix. In fact it looks and feels a lot like if you were using JavaScript to parse through this data, doesn't it? And that's the point…© Rick Strahl, West Wind Technologies, 2005-2012Posted in .NET  Web Api  JSON   Tweet !function(d,s,id){var js,fjs=d.getElementsByTagName(s)[0];if(!d.getElementById(id)){js=d.createElement(s);js.id=id;js.src="//platform.twitter.com/widgets.js";fjs.parentNode.insertBefore(js,fjs);}}(document,"script","twitter-wjs"); (function() { var po = document.createElement('script'); po.type = 'text/javascript'; po.async = true; po.src = 'https://apis.google.com/js/plusone.js'; var s = document.getElementsByTagName('script')[0]; s.parentNode.insertBefore(po, s); })();

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  • An Introduction to ASP.NET Web API

    - by Rick Strahl
    Microsoft recently released ASP.NET MVC 4.0 and .NET 4.5 and along with it, the brand spanking new ASP.NET Web API. Web API is an exciting new addition to the ASP.NET stack that provides a new, well-designed HTTP framework for creating REST and AJAX APIs (API is Microsoft’s new jargon for a service, in case you’re wondering). Although Web API ships and installs with ASP.NET MVC 4, you can use Web API functionality in any ASP.NET project, including WebForms, WebPages and MVC or just a Web API by itself. And you can also self-host Web API in your own applications from Console, Desktop or Service applications. If you're interested in a high level overview on what ASP.NET Web API is and how it fits into the ASP.NET stack you can check out my previous post: Where does ASP.NET Web API fit? In the following article, I'll focus on a practical, by example introduction to ASP.NET Web API. All the code discussed in this article is available in GitHub: https://github.com/RickStrahl/AspNetWebApiArticle [republished from my Code Magazine Article and updated for RTM release of ASP.NET Web API] Getting Started To start I’ll create a new empty ASP.NET application to demonstrate that Web API can work with any kind of ASP.NET project. Although you can create a new project based on the ASP.NET MVC/Web API template to quickly get up and running, I’ll take you through the manual setup process, because one common use case is to add Web API functionality to an existing ASP.NET application. This process describes the steps needed to hook up Web API to any ASP.NET 4.0 application. Start by creating an ASP.NET Empty Project. Then create a new folder in the project called Controllers. Add a Web API Controller Class Once you have any kind of ASP.NET project open, you can add a Web API Controller class to it. Web API Controllers are very similar to MVC Controller classes, but they work in any kind of project. Add a new item to this folder by using the Add New Item option in Visual Studio and choose Web API Controller Class, as shown in Figure 1. Figure 1: This is how you create a new Controller Class in Visual Studio   Make sure that the name of the controller class includes Controller at the end of it, which is required in order for Web API routing to find it. Here, the name for the class is AlbumApiController. For this example, I’ll use a Music Album model to demonstrate basic behavior of Web API. The model consists of albums and related songs where an album has properties like Name, Artist and YearReleased and a list of songs with a SongName and SongLength as well as an AlbumId that links it to the album. You can find the code for the model (and the rest of these samples) on Github. To add the file manually, create a new folder called Model, and add a new class Album.cs and copy the code into it. There’s a static AlbumData class with a static CreateSampleAlbumData() method that creates a short list of albums on a static .Current that I’ll use for the examples. Before we look at what goes into the controller class though, let’s hook up routing so we can access this new controller. Hooking up Routing in Global.asax To start, I need to perform the one required configuration task in order for Web API to work: I need to configure routing to the controller. Like MVC, Web API uses routing to provide clean, extension-less URLs to controller methods. Using an extension method to ASP.NET’s static RouteTable class, you can use the MapHttpRoute() (in the System.Web.Http namespace) method to hook-up the routing during Application_Start in global.asax.cs shown in Listing 1.using System; using System.Web.Routing; using System.Web.Http; namespace AspNetWebApi { public class Global : System.Web.HttpApplication { protected void Application_Start(object sender, EventArgs e) { RouteTable.Routes.MapHttpRoute( name: "AlbumVerbs", routeTemplate: "albums/{title}", defaults: new { symbol = RouteParameter.Optional, controller="AlbumApi" } ); } } } This route configures Web API to direct URLs that start with an albums folder to the AlbumApiController class. Routing in ASP.NET is used to create extensionless URLs and allows you to map segments of the URL to specific Route Value parameters. A route parameter, with a name inside curly brackets like {name}, is mapped to parameters on the controller methods. Route parameters can be optional, and there are two special route parameters – controller and action – that determine the controller to call and the method to activate respectively. HTTP Verb Routing Routing in Web API can route requests by HTTP Verb in addition to standard {controller},{action} routing. For the first examples, I use HTTP Verb routing, as shown Listing 1. Notice that the route I’ve defined does not include an {action} route value or action value in the defaults. Rather, Web API can use the HTTP Verb in this route to determine the method to call the controller, and a GET request maps to any method that starts with Get. So methods called Get() or GetAlbums() are matched by a GET request and a POST request maps to a Post() or PostAlbum(). Web API matches a method by name and parameter signature to match a route, query string or POST values. In lieu of the method name, the [HttpGet,HttpPost,HttpPut,HttpDelete, etc] attributes can also be used to designate the accepted verbs explicitly if you don’t want to follow the verb naming conventions. Although HTTP Verb routing is a good practice for REST style resource APIs, it’s not required and you can still use more traditional routes with an explicit {action} route parameter. When {action} is supplied, the HTTP verb routing is ignored. I’ll talk more about alternate routes later. When you’re finished with initial creation of files, your project should look like Figure 2.   Figure 2: The initial project has the new API Controller Album model   Creating a small Album Model Now it’s time to create some controller methods to serve data. For these examples, I’ll use a very simple Album and Songs model to play with, as shown in Listing 2. public class Song { public string AlbumId { get; set; } [Required, StringLength(80)] public string SongName { get; set; } [StringLength(5)] public string SongLength { get; set; } } public class Album { public string Id { get; set; } [Required, StringLength(80)] public string AlbumName { get; set; } [StringLength(80)] public string Artist { get; set; } public int YearReleased { get; set; } public DateTime Entered { get; set; } [StringLength(150)] public string AlbumImageUrl { get; set; } [StringLength(200)] public string AmazonUrl { get; set; } public virtual List<Song> Songs { get; set; } public Album() { Songs = new List<Song>(); Entered = DateTime.Now; // Poor man's unique Id off GUID hash Id = Guid.NewGuid().GetHashCode().ToString("x"); } public void AddSong(string songName, string songLength = null) { this.Songs.Add(new Song() { AlbumId = this.Id, SongName = songName, SongLength = songLength }); } } Once the model has been created, I also added an AlbumData class that generates some static data in memory that is loaded onto a static .Current member. The signature of this class looks like this and that's what I'll access to retrieve the base data:public static class AlbumData { // sample data - static list public static List<Album> Current = CreateSampleAlbumData(); /// <summary> /// Create some sample data /// </summary> /// <returns></returns> public static List<Album> CreateSampleAlbumData() { … }} You can check out the full code for the data generation online. Creating an AlbumApiController Web API shares many concepts of ASP.NET MVC, and the implementation of your API logic is done by implementing a subclass of the System.Web.Http.ApiController class. Each public method in the implemented controller is a potential endpoint for the HTTP API, as long as a matching route can be found to invoke it. The class name you create should end in Controller, which is how Web API matches the controller route value to figure out which class to invoke. Inside the controller you can implement methods that take standard .NET input parameters and return .NET values as results. Web API’s binding tries to match POST data, route values, form values or query string values to your parameters. Because the controller is configured for HTTP Verb based routing (no {action} parameter in the route), any methods that start with Getxxxx() are called by an HTTP GET operation. You can have multiple methods that match each HTTP Verb as long as the parameter signatures are different and can be matched by Web API. In Listing 3, I create an AlbumApiController with two methods to retrieve a list of albums and a single album by its title .public class AlbumApiController : ApiController { public IEnumerable<Album> GetAlbums() { var albums = AlbumData.Current.OrderBy(alb => alb.Artist); return albums; } public Album GetAlbum(string title) { var album = AlbumData.Current .SingleOrDefault(alb => alb.AlbumName.Contains(title)); return album; }} To access the first two requests, you can use the following URLs in your browser: http://localhost/aspnetWebApi/albumshttp://localhost/aspnetWebApi/albums/Dirty%20Deeds Note that you’re not specifying the actions of GetAlbum or GetAlbums in these URLs. Instead Web API’s routing uses HTTP GET verb to route to these methods that start with Getxxx() with the first mapping to the parameterless GetAlbums() method and the latter to the GetAlbum(title) method that receives the title parameter mapped as optional in the route. Content Negotiation When you access any of the URLs above from a browser, you get either an XML or JSON result returned back. The album list result for Chrome 17 and Internet Explorer 9 is shown Figure 3. Figure 3: Web API responses can vary depending on the browser used, demonstrating Content Negotiation in action as these two browsers send different HTTP Accept headers.   Notice that the results are not the same: Chrome returns an XML response and IE9 returns a JSON response. Whoa, what’s going on here? Shouldn’t we see the same result in both browsers? Actually, no. Web API determines what type of content to return based on Accept headers. HTTP clients, like browsers, use Accept headers to specify what kind of content they’d like to see returned. Browsers generally ask for HTML first, followed by a few additional content types. Chrome (and most other major browsers) ask for: Accept: text/html, application/xhtml+xml,application/xml; q=0.9,*/*;q=0.8 IE9 asks for: Accept: text/html, application/xhtml+xml, */* Note that Chrome’s Accept header includes application/xml, which Web API finds in its list of supported media types and returns an XML response. IE9 does not include an Accept header type that works on Web API by default, and so it returns the default format, which is JSON. This is an important and very useful feature that was missing from any previous Microsoft REST tools: Web API automatically switches output formats based on HTTP Accept headers. Nowhere in the server code above do you have to explicitly specify the output format. Rather, Web API determines what format the client is requesting based on the Accept headers and automatically returns the result based on the available formatters. This means that a single method can handle both XML and JSON results.. Using this simple approach makes it very easy to create a single controller method that can return JSON, XML, ATOM or even OData feeds by providing the appropriate Accept header from the client. By default you don’t have to worry about the output format in your code. Note that you can still specify an explicit output format if you choose, either globally by overriding the installed formatters, or individually by returning a lower level HttpResponseMessage instance and setting the formatter explicitly. More on that in a minute. Along the same lines, any content sent to the server via POST/PUT is parsed by Web API based on the HTTP Content-type of the data sent. The same formats allowed for output are also allowed on input. Again, you don’t have to do anything in your code – Web API automatically performs the deserialization from the content. Accessing Web API JSON Data with jQuery A very common scenario for Web API endpoints is to retrieve data for AJAX calls from the Web browser. Because JSON is the default format for Web API, it’s easy to access data from the server using jQuery and its getJSON() method. This example receives the albums array from GetAlbums() and databinds it into the page using knockout.js.$.getJSON("albums/", function (albums) { // make knockout template visible $(".album").show(); // create view object and attach array var view = { albums: albums }; ko.applyBindings(view); }); Figure 4 shows this and the next example’s HTML output. You can check out the complete HTML and script code at http://goo.gl/Ix33C (.html) and http://goo.gl/tETlg (.js). Figu Figure 4: The Album Display sample uses JSON data loaded from Web API.   The result from the getJSON() call is a JavaScript object of the server result, which comes back as a JavaScript array. In the code, I use knockout.js to bind this array into the UI, which as you can see, requires very little code, instead using knockout’s data-bind attributes to bind server data to the UI. Of course, this is just one way to use the data – it’s entirely up to you to decide what to do with the data in your client code. Along the same lines, I can retrieve a single album to display when the user clicks on an album. The response returns the album information and a child array with all the songs. The code to do this is very similar to the last example where we pulled the albums array:$(".albumlink").live("click", function () { var id = $(this).data("id"); // title $.getJSON("albums/" + id, function (album) { ko.applyBindings(album, $("#divAlbumDialog")[0]); $("#divAlbumDialog").show(); }); }); Here the URL looks like this: /albums/Dirty%20Deeds, where the title is the ID captured from the clicked element’s data ID attribute. Explicitly Overriding Output Format When Web API automatically converts output using content negotiation, it does so by matching Accept header media types to the GlobalConfiguration.Configuration.Formatters and the SupportedMediaTypes of each individual formatter. You can add and remove formatters to globally affect what formats are available and it’s easy to create and plug in custom formatters.The example project includes a JSONP formatter that can be plugged in to provide JSONP support for requests that have a callback= querystring parameter. Adding, removing or replacing formatters is a global option you can use to manipulate content. It’s beyond the scope of this introduction to show how it works, but you can review the sample code or check out my blog entry on the subject (http://goo.gl/UAzaR). If automatic processing is not desirable in a particular Controller method, you can override the response output explicitly by returning an HttpResponseMessage instance. HttpResponseMessage is similar to ActionResult in ASP.NET MVC in that it’s a common way to return an abstract result message that contains content. HttpResponseMessage s parsed by the Web API framework using standard interfaces to retrieve the response data, status code, headers and so on[MS2] . Web API turns every response – including those Controller methods that return static results – into HttpResponseMessage instances. Explicitly returning an HttpResponseMessage instance gives you full control over the output and lets you mostly bypass WebAPI’s post-processing of the HTTP response on your behalf. HttpResponseMessage allows you to customize the response in great detail. Web API’s attention to detail in the HTTP spec really shows; many HTTP options are exposed as properties and enumerations with detailed IntelliSense comments. Even if you’re new to building REST-based interfaces, the API guides you in the right direction for returning valid responses and response codes. For example, assume that I always want to return JSON from the GetAlbums() controller method and ignore the default media type content negotiation. To do this, I can adjust the output format and headers as shown in Listing 4.public HttpResponseMessage GetAlbums() { var albums = AlbumData.Current.OrderBy(alb => alb.Artist); // Create a new HttpResponse with Json Formatter explicitly var resp = new HttpResponseMessage(HttpStatusCode.OK); resp.Content = new ObjectContent<IEnumerable<Album>>( albums, new JsonMediaTypeFormatter()); // Get Default Formatter based on Content Negotiation //var resp = Request.CreateResponse<IEnumerable<Album>>(HttpStatusCode.OK, albums); resp.Headers.ConnectionClose = true; resp.Headers.CacheControl = new CacheControlHeaderValue(); resp.Headers.CacheControl.Public = true; return resp; } This example returns the same IEnumerable<Album> value, but it wraps the response into an HttpResponseMessage so you can control the entire HTTP message result including the headers, formatter and status code. In Listing 4, I explicitly specify the formatter using the JsonMediaTypeFormatter to always force the content to JSON.  If you prefer to use the default content negotiation with HttpResponseMessage results, you can create the Response instance using the Request.CreateResponse method:var resp = Request.CreateResponse<IEnumerable<Album>>(HttpStatusCode.OK, albums); This provides you an HttpResponse object that's pre-configured with the default formatter based on Content Negotiation. Once you have an HttpResponse object you can easily control most HTTP aspects on this object. What's sweet here is that there are many more detailed properties on HttpResponse than the core ASP.NET Response object, with most options being explicitly configurable with enumerations that make it easy to pick the right headers and response codes from a list of valid codes. It makes HTTP features available much more discoverable even for non-hardcore REST/HTTP geeks. Non-Serialized Results The output returned doesn’t have to be a serialized value but can also be raw data, like strings, binary data or streams. You can use the HttpResponseMessage.Content object to set a number of common Content classes. Listing 5 shows how to return a binary image using the ByteArrayContent class from a Controller method. [HttpGet] public HttpResponseMessage AlbumArt(string title) { var album = AlbumData.Current.FirstOrDefault(abl => abl.AlbumName.StartsWith(title)); if (album == null) { var resp = Request.CreateResponse<ApiMessageError>( HttpStatusCode.NotFound, new ApiMessageError("Album not found")); return resp; } // kinda silly - we would normally serve this directly // but hey - it's a demo. var http = new WebClient(); var imageData = http.DownloadData(album.AlbumImageUrl); // create response and return var result = new HttpResponseMessage(HttpStatusCode.OK); result.Content = new ByteArrayContent(imageData); result.Content.Headers.ContentType = new MediaTypeHeaderValue("image/jpeg"); return result; } The image retrieval from Amazon is contrived, but it shows how to return binary data using ByteArrayContent. It also demonstrates that you can easily return multiple types of content from a single controller method, which is actually quite common. If an error occurs - such as a resource can’t be found or a validation error – you can return an error response to the client that’s very specific to the error. In GetAlbumArt(), if the album can’t be found, we want to return a 404 Not Found status (and realistically no error, as it’s an image). Note that if you are not using HTTP Verb-based routing or not accessing a method that starts with Get/Post etc., you have to specify one or more HTTP Verb attributes on the method explicitly. Here, I used the [HttpGet] attribute to serve the image. Another option to handle the error could be to return a fixed placeholder image if no album could be matched or the album doesn’t have an image. When returning an error code, you can also return a strongly typed response to the client. For example, you can set the 404 status code and also return a custom error object (ApiMessageError is a class I defined) like this:return Request.CreateResponse<ApiMessageError>( HttpStatusCode.NotFound, new ApiMessageError("Album not found") );   If the album can be found, the image will be returned. The image is downloaded into a byte[] array, and then assigned to the result’s Content property. I created a new ByteArrayContent instance and assigned the image’s bytes and the content type so that it displays properly in the browser. There are other content classes available: StringContent, StreamContent, ByteArrayContent, MultipartContent, and ObjectContent are at your disposal to return just about any kind of content. You can create your own Content classes if you frequently return custom types and handle the default formatter assignments that should be used to send the data out . Although HttpResponseMessage results require more code than returning a plain .NET value from a method, it allows much more control over the actual HTTP processing than automatic processing. It also makes it much easier to test your controller methods as you get a response object that you can check for specific status codes and output messages rather than just a result value. Routing Again Ok, let’s get back to the image example. Using the original routing we have setup using HTTP Verb routing there's no good way to serve the image. In order to return my album art image I’d like to use a URL like this: http://localhost/aspnetWebApi/albums/Dirty%20Deeds/image In order to create a URL like this, I have to create a new Controller because my earlier routes pointed to the AlbumApiController using HTTP Verb routing. HTTP Verb based routing is great for representing a single set of resources such as albums. You can map operations like add, delete, update and read easily using HTTP Verbs. But you cannot mix action based routing into a an HTTP Verb routing controller - you can only map HTTP Verbs and each method has to be unique based on parameter signature. You can't have multiple GET operations to methods with the same signature. So GetImage(string id) and GetAlbum(string title) are in conflict in an HTTP GET routing scenario. In fact, I was unable to make the above Image URL work with any combination of HTTP Verb plus Custom routing using the single Albums controller. There are number of ways around this, but all involve additional controllers.  Personally, I think it’s easier to use explicit Action routing and then add custom routes if you need to simplify your URLs further. So in order to accommodate some of the other examples, I created another controller – AlbumRpcApiController – to handle all requests that are explicitly routed via actions (/albums/rpc/AlbumArt) or are custom routed with explicit routes defined in the HttpConfiguration. I added the AlbumArt() method to this new AlbumRpcApiController class. For the image URL to work with the new AlbumRpcApiController, you need a custom route placed before the default route from Listing 1.RouteTable.Routes.MapHttpRoute( name: "AlbumRpcApiAction", routeTemplate: "albums/rpc/{action}/{title}", defaults: new { title = RouteParameter.Optional, controller = "AlbumRpcApi", action = "GetAblums" } ); Now I can use either of the following URLs to access the image: Custom route: (/albums/rpc/{title}/image)http://localhost/aspnetWebApi/albums/PowerAge/image Action route: (/albums/rpc/action/{title})http://localhost/aspnetWebAPI/albums/rpc/albumart/PowerAge Sending Data to the Server To send data to the server and add a new album, you can use an HTTP POST operation. Since I’m using HTTP Verb-based routing in the original AlbumApiController, I can implement a method called PostAlbum()to accept a new album from the client. Listing 6 shows the Web API code to add a new album.public HttpResponseMessage PostAlbum(Album album) { if (!this.ModelState.IsValid) { // my custom error class var error = new ApiMessageError() { message = "Model is invalid" }; // add errors into our client error model for client foreach (var prop in ModelState.Values) { var modelError = prop.Errors.FirstOrDefault(); if (!string.IsNullOrEmpty(modelError.ErrorMessage)) error.errors.Add(modelError.ErrorMessage); else error.errors.Add(modelError.Exception.Message); } return Request.CreateResponse<ApiMessageError>(HttpStatusCode.Conflict, error); } // update song id which isn't provided foreach (var song in album.Songs) song.AlbumId = album.Id; // see if album exists already var matchedAlbum = AlbumData.Current .SingleOrDefault(alb => alb.Id == album.Id || alb.AlbumName == album.AlbumName); if (matchedAlbum == null) AlbumData.Current.Add(album); else matchedAlbum = album; // return a string to show that the value got here var resp = Request.CreateResponse(HttpStatusCode.OK, string.Empty); resp.Content = new StringContent(album.AlbumName + " " + album.Entered.ToString(), Encoding.UTF8, "text/plain"); return resp; } The PostAlbum() method receives an album parameter, which is automatically deserialized from the POST buffer the client sent. The data passed from the client can be either XML or JSON. Web API automatically figures out what format it needs to deserialize based on the content type and binds the content to the album object. Web API uses model binding to bind the request content to the parameter(s) of controller methods. Like MVC you can check the model by looking at ModelState.IsValid. If it’s not valid, you can run through the ModelState.Values collection and check each binding for errors. Here I collect the error messages into a string array that gets passed back to the client via the result ApiErrorMessage object. When a binding error occurs, you’ll want to return an HTTP error response and it’s best to do that with an HttpResponseMessage result. In Listing 6, I used a custom error class that holds a message and an array of detailed error messages for each binding error. I used this object as the content to return to the client along with my Conflict HTTP Status Code response. If binding succeeds, the example returns a string with the name and date entered to demonstrate that you captured the data. Normally, a method like this should return a Boolean or no response at all (HttpStatusCode.NoConent). The sample uses a simple static list to hold albums, so once you’ve added the album using the Post operation, you can hit the /albums/ URL to see that the new album was added. The client jQuery code to call the POST operation from the client with jQuery is shown in Listing 7. var id = new Date().getTime().toString(); var album = { "Id": id, "AlbumName": "Power Age", "Artist": "AC/DC", "YearReleased": 1977, "Entered": "2002-03-11T18:24:43.5580794-10:00", "AlbumImageUrl": http://ecx.images-amazon.com/images/…, "AmazonUrl": http://www.amazon.com/…, "Songs": [ { "SongName": "Rock 'n Roll Damnation", "SongLength": 3.12}, { "SongName": "Downpayment Blues", "SongLength": 4.22 }, { "SongName": "Riff Raff", "SongLength": 2.42 } ] } $.ajax( { url: "albums/", type: "POST", contentType: "application/json", data: JSON.stringify(album), processData: false, beforeSend: function (xhr) { // not required since JSON is default output xhr.setRequestHeader("Accept", "application/json"); }, success: function (result) { // reload list of albums page.loadAlbums(); }, error: function (xhr, status, p3, p4) { var err = "Error"; if (xhr.responseText && xhr.responseText[0] == "{") err = JSON.parse(xhr.responseText).message; alert(err); } }); The code in Listing 7 creates an album object in JavaScript to match the structure of the .NET Album class. This object is passed to the $.ajax() function to send to the server as POST. The data is turned into JSON and the content type set to application/json so that the server knows what to convert when deserializing in the Album instance. The jQuery code hooks up success and failure events. Success returns the result data, which is a string that’s echoed back with an alert box. If an error occurs, jQuery returns the XHR instance and status code. You can check the XHR to see if a JSON object is embedded and if it is, you can extract it by de-serializing it and accessing the .message property. REST standards suggest that updates to existing resources should use PUT operations. REST standards aside, I’m not a big fan of separating out inserts and updates so I tend to have a single method that handles both. But if you want to follow REST suggestions, you can create a PUT method that handles updates by forwarding the PUT operation to the POST method:public HttpResponseMessage PutAlbum(Album album) { return PostAlbum(album); } To make the corresponding $.ajax() call, all you have to change from Listing 7 is the type: from POST to PUT. Model Binding with UrlEncoded POST Variables In the example in Listing 7 I used JSON objects to post a serialized object to a server method that accepted an strongly typed object with the same structure, which is a common way to send data to the server. However, Web API supports a number of different ways that data can be received by server methods. For example, another common way is to use plain UrlEncoded POST  values to send to the server. Web API supports Model Binding that works similar (but not the same) as MVC's model binding where POST variables are mapped to properties of object parameters of the target method. This is actually quite common for AJAX calls that want to avoid serialization and the potential requirement of a JSON parser on older browsers. For example, using jQUery you might use the $.post() method to send a new album to the server (albeit one without songs) using code like the following:$.post("albums/",{AlbumName: "Dirty Deeds", YearReleased: 1976 … },albumPostCallback); Although the code looks very similar to the client code we used before passing JSON, here the data passed is URL encoded values (AlbumName=Dirty+Deeds&YearReleased=1976 etc.). Web API then takes this POST data and maps each of the POST values to the properties of the Album object in the method's parameter. Although the client code is different the server can both handle the JSON object, or the UrlEncoded POST values. Dynamic Access to POST Data There are also a few options available to dynamically access POST data, if you know what type of data you're dealing with. If you have POST UrlEncoded values, you can dynamically using a FormsDataCollection:[HttpPost] public string PostAlbum(FormDataCollection form) { return string.Format("{0} - released {1}", form.Get("AlbumName"),form.Get("RearReleased")); } The FormDataCollection is a very simple object, that essentially provides the same functionality as Request.Form[] in ASP.NET. Request.Form[] still works if you're running hosted in an ASP.NET application. However as a general rule, while ASP.NET's functionality is always available when running Web API hosted inside of an  ASP.NET application, using the built in classes specific to Web API makes it possible to run Web API applications in a self hosted environment outside of ASP.NET. If your client is sending JSON to your server, and you don't want to map the JSON to a strongly typed object because you only want to retrieve a few simple values, you can also accept a JObject parameter in your API methods:[HttpPost] public string PostAlbum(JObject jsonData) { dynamic json = jsonData; JObject jalbum = json.Album; JObject juser = json.User; string token = json.UserToken; var album = jalbum.ToObject<Album>(); var user = juser.ToObject<User>(); return String.Format("{0} {1} {2}", album.AlbumName, user.Name, token); } There quite a few options available to you to receive data with Web API, which gives you more choices for the right tool for the job. Unfortunately one shortcoming of Web API is that POST data is always mapped to a single parameter. This means you can't pass multiple POST parameters to methods that receive POST data. It's possible to accept multiple parameters, but only one can map to the POST content - the others have to come from the query string or route values. I have a couple of Blog POSTs that explain what works and what doesn't here: Passing multiple POST parameters to Web API Controller Methods Mapping UrlEncoded POST Values in ASP.NET Web API   Handling Delete Operations Finally, to round out the server API code of the album example we've been discussin, here’s the DELETE verb controller method that allows removal of an album by its title:public HttpResponseMessage DeleteAlbum(string title) { var matchedAlbum = AlbumData.Current.Where(alb => alb.AlbumName == title) .SingleOrDefault(); if (matchedAlbum == null) return new HttpResponseMessage(HttpStatusCode.NotFound); AlbumData.Current.Remove(matchedAlbum); return new HttpResponseMessage(HttpStatusCode.NoContent); } To call this action method using jQuery, you can use:$(".removeimage").live("click", function () { var $el = $(this).parent(".album"); var txt = $el.find("a").text(); $.ajax({ url: "albums/" + encodeURIComponent(txt), type: "Delete", success: function (result) { $el.fadeOut().remove(); }, error: jqError }); }   Note the use of the DELETE verb in the $.ajax() call, which routes to DeleteAlbum on the server. DELETE is a non-content operation, so you supply a resource ID (the title) via route value or the querystring. Routing Conflicts In all requests with the exception of the AlbumArt image example shown so far, I used HTTP Verb routing that I set up in Listing 1. HTTP Verb Routing is a recommendation that is in line with typical REST access to HTTP resources. However, it takes quite a bit of effort to create REST-compliant API implementations based only on HTTP Verb routing only. You saw one example that didn’t really fit – the return of an image where I created a custom route albums/{title}/image that required creation of a second controller and a custom route to work. HTTP Verb routing to a controller does not mix with custom or action routing to the same controller because of the limited mapping of HTTP verbs imposed by HTTP Verb routing. To understand some of the problems with verb routing, let’s look at another example. Let’s say you create a GetSortableAlbums() method like this and add it to the original AlbumApiController accessed via HTTP Verb routing:[HttpGet] public IQueryable<Album> SortableAlbums() { var albums = AlbumData.Current; // generally should be done only on actual queryable results (EF etc.) // Done here because we're running with a static list but otherwise might be slow return albums.AsQueryable(); } If you compile this code and try to now access the /albums/ link, you get an error: Multiple Actions were found that match the request. HTTP Verb routing only allows access to one GET operation per parameter/route value match. If more than one method exists with the same parameter signature, it doesn’t work. As I mentioned earlier for the image display, the only solution to get this method to work is to throw it into another controller. Because I already set up the AlbumRpcApiController I can add the method there. First, I should rename the method to SortableAlbums() so I’m not using a Get prefix for the method. This also makes the action parameter look cleaner in the URL - it looks less like a method and more like a noun. I can then create a new route that handles direct-action mapping:RouteTable.Routes.MapHttpRoute( name: "AlbumRpcApiAction", routeTemplate: "albums/rpc/{action}/{title}", defaults: new { title = RouteParameter.Optional, controller = "AlbumRpcApi", action = "GetAblums" } ); As I am explicitly adding a route segment – rpc – into the route template, I can now reference explicit methods in the Web API controller using URLs like this: http://localhost/AspNetWebApi/rpc/SortableAlbums Error Handling I’ve already done some minimal error handling in the examples. For example in Listing 6, I detected some known-error scenarios like model validation failing or a resource not being found and returning an appropriate HttpResponseMessage result. But what happens if your code just blows up or causes an exception? If you have a controller method, like this:[HttpGet] public void ThrowException() { throw new UnauthorizedAccessException("Unauthorized Access Sucka"); } You can call it with this: http://localhost/AspNetWebApi/albums/rpc/ThrowException The default exception handling displays a 500-status response with the serialized exception on the local computer only. When you connect from a remote computer, Web API throws back a 500  HTTP Error with no data returned (IIS then adds its HTML error page). The behavior is configurable in the GlobalConfiguration:GlobalConfiguration .Configuration .IncludeErrorDetailPolicy = IncludeErrorDetailPolicy.Never; If you want more control over your error responses sent from code, you can throw explicit error responses yourself using HttpResponseException. When you throw an HttpResponseException the response parameter is used to generate the output for the Controller action. [HttpGet] public void ThrowError() { var resp = Request.CreateResponse<ApiMessageError>( HttpStatusCode.BadRequest, new ApiMessageError("Your code stinks!")); throw new HttpResponseException(resp); } Throwing an HttpResponseException stops the processing of the controller method and immediately returns the response you passed to the exception. Unlike other Exceptions fired inside of WebAPI, HttpResponseException bypasses the Exception Filters installed and instead just outputs the response you provide. In this case, the serialized ApiMessageError result string is returned in the default serialization format – XML or JSON. You can pass any content to HttpResponseMessage, which includes creating your own exception objects and consistently returning error messages to the client. Here’s a small helper method on the controller that you might use to send exception info back to the client consistently:private void ThrowSafeException(string message, HttpStatusCode statusCode = HttpStatusCode.BadRequest) { var errResponse = Request.CreateResponse<ApiMessageError>(statusCode, new ApiMessageError() { message = message }); throw new HttpResponseException(errResponse); } You can then use it to output any captured errors from code:[HttpGet] public void ThrowErrorSafe() { try { List<string> list = null; list.Add("Rick"); } catch (Exception ex) { ThrowSafeException(ex.Message); } }   Exception Filters Another more global solution is to create an Exception Filter. Filters in Web API provide the ability to pre- and post-process controller method operations. An exception filter looks at all exceptions fired and then optionally creates an HttpResponseMessage result. Listing 8 shows an example of a basic Exception filter implementation.public class UnhandledExceptionFilter : ExceptionFilterAttribute { public override void OnException(HttpActionExecutedContext context) { HttpStatusCode status = HttpStatusCode.InternalServerError; var exType = context.Exception.GetType(); if (exType == typeof(UnauthorizedAccessException)) status = HttpStatusCode.Unauthorized; else if (exType == typeof(ArgumentException)) status = HttpStatusCode.NotFound; var apiError = new ApiMessageError() { message = context.Exception.Message }; // create a new response and attach our ApiError object // which now gets returned on ANY exception result var errorResponse = context.Request.CreateResponse<ApiMessageError>(status, apiError); context.Response = errorResponse; base.OnException(context); } } Exception Filter Attributes can be assigned to an ApiController class like this:[UnhandledExceptionFilter] public class AlbumRpcApiController : ApiController or you can globally assign it to all controllers by adding it to the HTTP Configuration's Filters collection:GlobalConfiguration.Configuration.Filters.Add(new UnhandledExceptionFilter()); The latter is a great way to get global error trapping so that all errors (short of hard IIS errors and explicit HttpResponseException errors) return a valid error response that includes error information in the form of a known-error object. Using a filter like this allows you to throw an exception as you normally would and have your filter create a response in the appropriate output format that the client expects. For example, an AJAX application can on failure expect to see a JSON error result that corresponds to the real error that occurred rather than a 500 error along with HTML error page that IIS throws up. You can even create some custom exceptions so you can differentiate your own exceptions from unhandled system exceptions - you often don't want to display error information from 'unknown' exceptions as they may contain sensitive system information or info that's not generally useful to users of your application/site. This is just one example of how ASP.NET Web API is configurable and extensible. Exception filters are just one example of how you can plug-in into the Web API request flow to modify output. Many more hooks exist and I’ll take a closer look at extensibility in Part 2 of this article in the future. Summary Web API is a big improvement over previous Microsoft REST and AJAX toolkits. The key features to its usefulness are its ease of use with simple controller based logic, familiar MVC-style routing, low configuration impact, extensibility at all levels and tight attention to exposing and making HTTP semantics easily discoverable and easy to use. Although none of the concepts used in Web API are new or radical, Web API combines the best of previous platforms into a single framework that’s highly functional, easy to work with, and extensible to boot. I think that Microsoft has hit a home run with Web API. Related Resources Where does ASP.NET Web API fit? Sample Source Code on GitHub Passing multiple POST parameters to Web API Controller Methods Mapping UrlEncoded POST Values in ASP.NET Web API Creating a JSONP Formatter for ASP.NET Web API Removing the XML Formatter from ASP.NET Web API Applications© Rick Strahl, West Wind Technologies, 2005-2012Posted in Web Api   Tweet !function(d,s,id){var js,fjs=d.getElementsByTagName(s)[0];if(!d.getElementById(id)){js=d.createElement(s);js.id=id;js.src="//platform.twitter.com/widgets.js";fjs.parentNode.insertBefore(js,fjs);}}(document,"script","twitter-wjs"); (function() { var po = document.createElement('script'); po.type = 'text/javascript'; po.async = true; po.src = 'https://apis.google.com/js/plusone.js'; var s = document.getElementsByTagName('script')[0]; s.parentNode.insertBefore(po, s); })();

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  • UITableView Core Data reordering

    - by PCWiz
    I know this question has been asked before, and I took a look at the answer to this question. However, I'm still confused as to how to implement reordering with a UITableView in a Core Data project. What I know is that I need to have a "displayOrder" attribute in my Entity to track the order of items, and I need to enumerate through all the objects in the fetched results and set their displayOrder attribute. In the given code in the question I linked to, the table view delegate method calls a method like this [self FF_fetchResults];, and the code for that method is not given so its hard to tell what exactly it is. Is there any sample code that demonstrates this? That would be simpler to look at than sharing large chunks of code. Thanks

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  • UITableView Core Data reordering

    - by PCWiz
    I know this question has been asked before, and I took a look at the answer to this question. However, I'm still confused as to how to implement reordering with a UITableView in a Core Data project. What I know is that I need to have a "displayOrder" attribute in my Entity to track the order of items, and I need to enumerate through all the objects in the fetched results and set their displayOrder attribute. In the given code in the question I linked to, the table view delegate method calls a method like this [self FF_fetchResults];, and the code for that method is not given so its hard to tell what exactly it is. Is there any sample code that demonstrates this? That would be simpler to look at than sharing large chunks of code. Thanks

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  • Android Eclipse Error "Android Packaging Problem"

    - by Peter Delaney
    Hello; I am getting an error in my Problems tab for my Android Project in Eclipse. The error is "Android Packaging Problem" with an Unknown location. Unknown Error NullPointerException I cannot determine what this problem is. My project was working a few hours ago. The only change I made was to add a public interface ITrackDao to my project and implement it. There are no errors associated with this. I am not even sure where to begin to look. I cannot launch the application. Can someone give me an idea on what area I can look into? Thanks Peter

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  • Problem with adding Appendix in Latex

    - by Andrew
    Hi all, I tried the first time to add an appendix to my thesis, here are the commands that I used. \appendix \chapter{Appendices} \input{appendix} The output looks than as follows: Appendix A Appendices A.1 My first appendix ..... It does not look to bad, but what is irritating is the Appendices entry after Appendix A. Is there any possibilty I could get rid of it? If I try the following commands: \appendix \input{appendix} The output looks than as follows: .1 My first appendix ... Also not how it is intended. Ideally, it would look like this here: Appendix A A.1 My first appendix ..... Any idea how to do that? Andrew

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  • Custom MKPinAnnotation callout view similar to Default MKPinAnnotation

    - by Sijo
    i want to create a custom callout bubble on MKMapView. But i want to create the call out bubble in the same manner of default bubble. So how to create a View look like annotaion in this image I want a custom custom view which look like "Parked Location" annotaion in the following image. with custom width, height etc. P I am not able to add required details in Default bubble. Thats why am creating custom bubble. Plz help me..thanks..

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  • Access to content of Lotus Notes database without Lotus Notes software installed

    - by Fortilan
    I am looking for a programatic way to access content in a Lotus Notes database (.nsf file) without having Lotus Notes software installed. Python would be preferred but I'm also willing to look at other languages e.g. C/C++ or other means e.g. SQL From what I have read, all of the methods e.g. Python COM access, pyodbc rely on having Lotus Notes server software installed. The problem I am trying to solve is to read the content and look for references (URL's back to a web site that is undergoing maintenance and the addresses in the web site will change) As a start, I want to get a list of references and hope to be able to replace them with the new references to the modified web site. Any ideas on how best to do this welcome :)

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  • Adventures in MVVM &ndash; My ViewModel Base

    - by Brian Genisio's House Of Bilz
    More Adventures in MVVM First, I’d like to say: THIS IS NOT A NEW MVVM FRAMEWORK. I tend to believe that MVVM support code should be specific to the system you are building and the developers working on it.  I have yet to find an MVVM framework that does everything I want it to without doing too much.  Don’t get me wrong… there are some good frameworks out there.  I just like to pick and choose things that make sense for me.  I’d also like to add that some of these features only work in WPF.  As of Silveright 4, they don’t support binding to dynamic properties, so some of the capabilities are lost. That being said, I want to share my ViewModel base class with the world.  I have had several conversations with people about the problems I have solved using this ViewModel base.  A while back, I posted an article about some experiments with a “Rails Inspired ViewModel”.  What followed from those ideas was a ViewModel base class that I take with me and use in my projects.  It has a lot of features, all designed to reduce the friction in writing view models. I have put the code out on Codeplex under the project: ViewModelSupport. Finally, this article focuses on the ViewModel and only glosses over the View and the Model.  Without all three, you don’t have MVVM.  But this base class is for the ViewModel, so that is what I am focusing on. Features: Automatic Command Plumbing Property Change Notification Strongly Typed Property Getter/Setters Dynamic Properties Default Property values Derived Properties Automatic Method Execution Command CanExecute Change Notification Design-Time Detection What about Silverlight? Automatic Command Plumbing This feature takes the plumbing out of creating commands.  The common pattern for commands in a ViewModel is to have an Execute method as well as an optional CanExecute method.  To plumb that together, you create an ICommand Property, and set it in the constructor like so: Before public class AutomaticCommandViewModel { public AutomaticCommandViewModel() { MyCommand = new DelegateCommand(Execute_MyCommand, CanExecute_MyCommand); } public void Execute_MyCommand() { // Do something } public bool CanExecute_MyCommand() { // Are we in a state to do something? return true; } public DelegateCommand MyCommand { get; private set; } } With the base class, this plumbing is automatic and the property (MyCommand of type ICommand) is created for you.  The base class uses the convention that methods be prefixed with Execute_ and CanExecute_ in order to be plumbed into commands with the property name after the prefix.  You are left to be expressive with your behavior without the plumbing.  If you are wondering how CanExecuteChanged is raised, see the later section “Command CanExecute Change Notification”. After public class AutomaticCommandViewModel : ViewModelBase { public void Execute_MyCommand() { // Do something } public bool CanExecute_MyCommand() { // Are we in a state to do something? return true; } }   Property Change Notification One thing that always kills me when implementing ViewModels is how to make properties that notify when they change (via the INotifyPropertyChanged interface).  There have been many attempts to make this more automatic.  My base class includes one option.  There are others, but I feel like this works best for me. The common pattern (without my base class) is to create a private backing store for the variable and specify a getter that returns the private field.  The setter will set the private field and fire an event that notifies the change, only if the value has changed. Before public class PropertyHelpersViewModel : INotifyPropertyChanged { private string text; public string Text { get { return text; } set { if(text != value) { text = value; RaisePropertyChanged("Text"); } } } protected void RaisePropertyChanged(string propertyName) { var handlers = PropertyChanged; if(handlers != null) handlers(this, new PropertyChangedEventArgs(propertyName)); } public event PropertyChangedEventHandler PropertyChanged; } This way of defining properties is error-prone and tedious.  Too much plumbing.  My base class eliminates much of that plumbing with the same functionality: After public class PropertyHelpersViewModel : ViewModelBase { public string Text { get { return Get<string>("Text"); } set { Set("Text", value);} } }   Strongly Typed Property Getters/Setters It turns out that we can do better than that.  We are using a strongly typed language where the use of “Magic Strings” is often frowned upon.  Lets make the names in the getters and setters strongly typed: A refinement public class PropertyHelpersViewModel : ViewModelBase { public string Text { get { return Get(() => Text); } set { Set(() => Text, value); } } }   Dynamic Properties In C# 4.0, we have the ability to program statically OR dynamically.  This base class lets us leverage the powerful dynamic capabilities in our ecosystem. (This is how the automatic commands are implemented, BTW)  By calling Set(“Foo”, 1), you have now created a dynamic property called Foo.  It can be bound against like any static property.  The opportunities are endless.  One great way to exploit this behavior is if you have a customizable view engine with templates that bind to properties defined by the user.  The base class just needs to create the dynamic properties at runtime from information in the model, and the custom template can bind even though the static properties do not exist. All dynamic properties still benefit from the notifiable capabilities that static properties do. For any nay-sayers out there that don’t like using the dynamic features of C#, just remember this: the act of binding the View to a ViewModel is dynamic already.  Why not exploit it?  Get over it :) Just declare the property dynamically public class DynamicPropertyViewModel : ViewModelBase { public DynamicPropertyViewModel() { Set("Foo", "Bar"); } } Then reference it normally <TextBlock Text="{Binding Foo}" />   Default Property Values The Get() method also allows for default properties to be set.  Don’t set them in the constructor.  Set them in the property and keep the related code together: public string Text { get { return Get(() => Text, "This is the default value"); } set { Set(() => Text, value);} }   Derived Properties This is something I blogged about a while back in more detail.  This feature came from the chaining of property notifications when one property affects the results of another, like this: Before public class DependantPropertiesViewModel : ViewModelBase { public double Score { get { return Get(() => Score); } set { Set(() => Score, value); RaisePropertyChanged("Percentage"); RaisePropertyChanged("Output"); } } public int Percentage { get { return (int)(100 * Score); } } public string Output { get { return "You scored " + Percentage + "%."; } } } The problem is: The setter for Score has to be responsible for notifying the world that Percentage and Output have also changed.  This, to me, is backwards.    It certainly violates the “Single Responsibility Principle.” I have been bitten in the rear more than once by problems created from code like this.  What we really want to do is invert the dependency.  Let the Percentage property declare that it changes when the Score Property changes. After public class DependantPropertiesViewModel : ViewModelBase { public double Score { get { return Get(() => Score); } set { Set(() => Score, value); } } [DependsUpon("Score")] public int Percentage { get { return (int)(100 * Score); } } [DependsUpon("Percentage")] public string Output { get { return "You scored " + Percentage + "%."; } } }   Automatic Method Execution This one is extremely similar to the previous, but it deals with method execution as opposed to property.  When you want to execute a method triggered by property changes, let the method declare the dependency instead of the other way around. Before public class DependantMethodsViewModel : ViewModelBase { public double Score { get { return Get(() => Score); } set { Set(() => Score, value); WhenScoreChanges(); } } public void WhenScoreChanges() { // Handle this case } } After public class DependantMethodsViewModel : ViewModelBase { public double Score { get { return Get(() => Score); } set { Set(() => Score, value); } } [DependsUpon("Score")] public void WhenScoreChanges() { // Handle this case } }   Command CanExecute Change Notification Back to Commands.  One of the responsibilities of commands that implement ICommand – it must fire an event declaring that CanExecute() needs to be re-evaluated.  I wanted to wait until we got past a few concepts before explaining this behavior.  You can use the same mechanism here to fire off the change.  In the CanExecute_ method, declare the property that it depends upon.  When that property changes, the command will fire a CanExecuteChanged event, telling the View to re-evaluate the state of the command.  The View will make appropriate adjustments, like disabling the button. DependsUpon works on CanExecute methods as well public class CanExecuteViewModel : ViewModelBase { public void Execute_MakeLower() { Output = Input.ToLower(); } [DependsUpon("Input")] public bool CanExecute_MakeLower() { return !string.IsNullOrWhiteSpace(Input); } public string Input { get { return Get(() => Input); } set { Set(() => Input, value);} } public string Output { get { return Get(() => Output); } set { Set(() => Output, value); } } }   Design-Time Detection If you want to add design-time data to your ViewModel, the base class has a property that lets you ask if you are in the designer.  You can then set some default values that let your designer see what things might look like in runtime. Use the IsInDesignMode property public DependantPropertiesViewModel() { if(IsInDesignMode) { Score = .5; } }   What About Silverlight? Some of the features in this base class only work in WPF.  As of version 4, Silverlight does not support binding to dynamic properties.  This, in my opinion, is a HUGE limitation.  Not only does it keep you from using many of the features in this ViewModel, it also keeps you from binding to ViewModels designed in IronRuby.  Does this mean that the base class will not work in Silverlight?  No.  Many of the features outlined in this article WILL work.  All of the property abstractions are functional, as long as you refer to them statically in the View.  This, of course, means that the automatic command hook-up doesn’t work in Silverlight.  You need to plumb it to a static property in order for the Silverlight View to bind to it.  Can I has a dynamic property in SL5?     Good to go? So, that concludes the feature explanation of my ViewModel base class.  Feel free to take it, fork it, whatever.  It is hosted on CodePlex.  When I find other useful additions, I will add them to the public repository.  I use this base class every day.  It is mature, and well tested.  If, however, you find any problems with it, please let me know!  Also, feel free to suggest patches to me via the CodePlex site.  :)

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  • Google Reader API HTTP Response parsing (Objective C)

    - by JustinXXVII
    Using the API, trying to get items in a specific feed returns this: {“direction”:”ltr”,”id”:”feed/http://arstechnica.com/index.rssx”,”title”:”Ars Technica”,”description”:”The Art of Technology”,”self”:[{"href":"http://www.google.com/reader/api/0/stream/contents/feed/http://arstechnica.com/index.rssx?ot\u003d1273193172856169\u0026r\u003dn\u0026xt\u003duser/-/state/com.google/read\u0026n\u003d4\u0026ck\u003d1273193873\u0026client\u003diPadReader"}],”alternate”:[{"href":"http://arstechnica.com/index.php","type":"text/html"}],”updated”:1273193873,”items”:[]} They look like key/value pairs but it’s plain text with UTF8 String encoding and won’t encode into a dictionary. I’m using Objective-C and I’m not sure where to go from here. So far I’ve been able to parse the XML response for unread items, but parsing the plain-text doesn’t look feasible. What is your practice?

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  • OutOfMemoryException - out of ideas II

    - by Captain Comic
    Hello, This question is related to my previous question. The storyline: I have an application which consumes a lot of memory if you look at task manager VMSize. I am trying to find out what consumes this amount of memory. You see in the picture below that VM size is 2,46 GB Ok now I am looking at .net performance counters Committed and reserved bytes add up to only 1,2 GB Now lets look at windb sos debugging. Let's run eeheap -gc command The heap size used by GC is only 340 MB. Where is the rest of used memory? I need to discover why WM size in TaskManager is 2.4 GB

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  • issues horizontal scrolling using jQuery.ScrollTo / jQuery.SerialScroll

    - by kapil.israni
    Hi, I am trying to develop auto horizontal scrolling for our website using - jQuery.ScrollTo / jQuery.SerialScroll. I am not sure if this is the best jquery library to do that, but if there's something better, please let me know. Here's the behavior that I want, check out foursquare's "Recent Activity" list. The data that will refresh will come from a ajax request that I make every few seconds using window.setInterval. I am not really a CSS/java script guy so I havent been able to figure out jQuery.SerialScroll. Here's the website - look at the "Live job Feeds" list. Currently the list does refresh the data coming from the ajax call, but I dont see the effect, the animation, in fact I dont even think serialScroll is being used. Right now I am doing a - $('#feed-ticker').prepend(content) to pre-append the newly arrived data. You can do a view source to look at the current code. Any help would be really appreciated. Thanks.

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