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• How to record different authentication types (username / password vs token based) in audit log

  - by RM

  I have two types of users for my system, normal human users with a username / password, and delegation authorized accounts through OAuth (i.e. using a token identifier). The information that is stored for each is quite different, and are managed by different subsytems. They do however interact with the same tables / data within the system, so I need to maintain the audit trail regardless of whether human user, or token-based user modified the data. My solution at the moment is to have a table called something like AuditableIdentity, and then have the two types inheriting off that table (either in the single table, or as two seperate tables with 1 to 1 PK with AuditableIdentity. All operations would use the common AuditableIdentity PK for CreatedBy, ModifiedBy etc columns. There isn't any FK constraint on the audit columns, so any text can go in there, but I want an easy way to easily determine whether it was a human or system that made the change, and joining to the one AuditableIdentity table seems like a clean way to do that? Is there a best practice for this scenario? Is this an appropriate way of approaching the problem - or would you not bother with the common table and just rely on joins (to the two seperate un-related user / token tables) later to determine which user type matches which audit records?

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• How to allow users to define financial formulas in a C# app

  - by Peter Morris

  I need to allow my users to be able to define formulas which will calculate values based on data. For example //Example 1 return GetMonetaryAmountFromDatabase("Amount due") * 1.2; //Example 2 return GetMonetaryAmountFromDatabase("Amount due") * GetFactorFromDatabase("Discount"); I will need to allow / * + - operations, also to assign local variables and execute IF statements, like so var amountDue = GetMonetaryAmountFromDatabase("Amount due"); if (amountDue > 100000) return amountDue * 0.75; if (amountDue > 50000) return amountDue * 0.9; return amountDue; The scenario is complicated because I have the following structure.. Customer (a few hundred) Configuration (about 10 per customer) Item (about 10,000 per customer configuration) So I will perform a 3 level loop. At each "Configuration" level I will start a DB transaction and compile the forumlas, each "Item" will use the same transaction + compiled formulas (there are about 20 formulas per configuration, each item will use all of them). This further complicates things because I can't just use the compiler services as it would result in continued memory usage growth. I can't use a new AppDomain per each "Configuration" loop level because some of the references I need to pass cannot be marshalled. Any suggestions?

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• I'm trying to handle the updates on 2 related tables in one DetailsView using Jquery and Linq, and h

  - by Ben Reisner

  Given two related tables (reports, report_fields) where there can be many report_fields entries for each reports entry, I need to allow the user to enter new report_fields, delete existing report_fields, and re-arrange the order. Currently I am using a DetailsView to handle the editing of the reports. I added some logic to handle report_fields, and currently it allows you to succesfully re-arrange the order, but i'm a little stumped as to the best way to add new items, or delete existing items. The basic logic I have is that each report_fields is represented by a . It has a description as the text, and a field for each field in the report_fields table. I use JQuery Sortable to allow the user to re-arrange the LIs. Abbreviated Create Table Statements:(foreign key constraint ignored for brevity) create table report( id integer primary key identity, reportname varchar(250) ) create table report_fields( id integer primary key identity, reportID integer, keyname integer, keyvalue integer, field_order integer ) My abbreviated markup: <asp:DetailsView ...> ... <asp:TemplateField HeaderText="Fields"> <EditItemTemplate> <ul class="MySortable"> <asp:Repeater ID="Repeater1" runat="server" DataSource='<%# Eval("report_fields") %>'> <ItemTemplate> <li> <%# Eval("keyname") %>: <%# Eval("keyvalue") %> <input type="hidden" name="keyname[]" value='<%# Eval("keyname") %>' /> <input type="hidden" name="keyvalue[]" value='<%# Eval("keyvalue") %>' /> </li> </ItemTemplate> </asp:Repeater> </ul> </EditItemTemplate> </asp:TemplateField> </asp:DetailsView> <asp:LinqDataSource ID="LinqDataSource2" onupdating="LinqDataSource2_Updating" table=reports ... /> $(function() { $(".MySortable").sortable({ placeholder: 'MySortable-highlight' }).disableSelection(); }); Code Behind Class: public partial class Administration_AddEditReport protected void LinqDataSource2_Updating(object sender, LinqDataSourceUpdateEventArgs e) { report r = (report)e.NewObject; MyDataContext dc = new MyDataContext(); var fields = from f in dc.report_fields where f.reportID == r.id select f; dc.report_fields.DeleteAllOnSubmit(fields); NameValueCollection nvc = Request.Params; string[] keyname = nvc["keyname[]"].Split(','); string[] keyvalue = nvc["keyvalue[]"].Split(','); for (int i = 0; i < keyname.Length; i++) { report_field rf = new report_field(); rf.reportID = r.id; rf.keyname = keyname[i]; rf.keyvalue = keyvalue[i]; rf.field_order = i; dc.report_fields.InsertOnSubmit(rf); } dc.SubmitChanges(); } }

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• Pass a data.frame column name to a function

  - by Kevin Middleton

  I'm trying to write a function to accept a data.frame (x) and a column from it. The function performs some calculations on x and later returns another data.frame. I'm stuck on the best-practices method to pass the column name to the function. The two minimal examples fun1 and fun2 below produce the desired result, being able to perform operations on x$column, using max() as an example. However, both rely on the seemingly (at least to me) inelegant (1) call to substitute() and possibly eval() and (2) the need to pass the column name as a character vector. fun1 <- function(x, column){ do.call("max", list(substitute(x[a], list(a = column)))) } fun2 <- function(x, column){ max(eval((substitute(x[a], list(a = column))))) } df <- data.frame(A = 1:20, B = rnorm(10)) fun1(df, "B") fun2(df, "B") I would like to be able to call the function as fun(df, B), for example. Other options I have considered but have not tried: Pass column as an integer of the column number. I think this would avoid substitute(). Ideally, the function could accept either. with(x, get(column)), but, even if it works, I think this would still require substitute Make use of formula() and match.call(), neither of which I have much experience with. Subquestion: Is do.call() preferred over eval()? Thanks, Kevin

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• Generics vs inheritance (whenh no collection classes are involved)

  - by Ram

  This is an extension of this questionand probably might even be a duplicate of some other question(If so, please forgive me). I see from MSDN that generics are usually used with collections The most common use for generic classes is with collections like linked lists, hash tables, stacks, queues, trees and so on where operations such as adding and removing items from the collection are performed in much the same way regardless of the type of data being stored. The examples I have seen also validate the above statement. Can someone give a valid use of generics in a real-life scenario which does not involve any collections ? Pedantically, I was thinking about making an example which does not involve collections public class Animal<T> { public void Speak() { Console.WriteLine("I am an Animal and my type is " + typeof(T).ToString()); } public void Eat() { //Eat food } } public class Dog { public void WhoAmI() { Console.WriteLine(this.GetType().ToString()); } } and "An Animal of type Dog" will be Animal<Dog> magic = new Animal<Dog>(); It is entirely possible to have Dog getting inherited from Animal (Assuming a non-generic version of Animal)Dog:Animal Therefore Dog is an Animal Another example I was thinking was a BankAccount. It can be BankAccount<Checking>,BankAccount<Savings>. This can very well be Checking:BankAccount and Savings:BankAccount. Are there any best practices to determine if we should go with generics or with inheritance ?

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• Strange EListError occurance (when accessing variable-defined index)

  - by michal

  Hi, I have a TList which stores some objects. Now I have a function which does some operations on that list: function SomeFunct(const AIndex: integer): IInterface begin if (AIndex > -1) and (AIndex < fMgr.Windows.Count ) then begin if (fMgr.Windows[AIndex] <> nil) then begin if not Supports(TForm(fMgr.Windows[AIndex]), IMyFormInterface, result) then result:= nil; end; end else result:= nil; end; now, what is really strange is that accessing fMgr.Windows with any proper index causes EListError... However if i hard-code it (in example, replace AIndex with value 0 or 1) it works fine. I tried debugging it, the function gets called twice, with arguments 0 and 1 (as supposed). while AIndex = 0, evaluating fMgr.Windows[AIndex] results in EListError at $someAddress, while evaluating fMgr.Windws[0] instead - returns proper results ... what is even more strange, even though there is an EListError, the function returns proper data ... and doesn't show anything. Just info on two EListError memory leaks on shutdown (using FastMM) any ideas what could be wrong?! Thanks in advance michal

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• Mysql Server Optimization

  - by Ish Kumar

  Hi Geeks, We are having serious MySQL(InnoDB) performance issues at a moment when we do: (10-20) insertions on TABLE1 (10-20) updates on TABLE2 Note: Both above operations happens within fraction of a second. And this occurs every few (10-15) minutes. And all online users (approx 400-600) doing read operation on join of TABLE1 & TABLE2 every 1 second. Here is our mysql configuration info: http://docs.google.com/View?id=dfrswh7c_117fmgcmb44 Issues: Lot queries wait and expire later (saw it from phpmyadmin / processes). My poor MySQL server crashes sometimes Questions Q1: Any suggestions to optimize at MySQL level? Q2: I thinking to use persistent connections at application level, is it right? Info Added Later: Database Engine: InnoDB TABLE1 : 400,000 rows (inserting 8,000 daily) & TABLE2: 8,000 rows 1 second query: SELECT b.id, b.user_id, b.description, b.debit, b.created, b.price, u.username, u.email, u.mobile FROM TABLE1 b, TABLE2 u WHERE b.credit = 0 AND b.user_id = u.id AND b.auction_id = "12345" ORDER BY b.id DESC LIMIT 10; // there are few more but they are not so critical. Indexing is good, we are using them wisely. In above query all id's are indexed And TABLE1 has frequent insertions and TABLE2 has frequent updates.

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• Axis webservice calls fail sometimes, access.log shows content!

  - by epischel

  Hi, our app is a webservice client (axis 1) to a third party webservice (also axis 1). We use it for some years now. Since a few weeks, we (as a client) get sometimes HTTP status 400 (bad request) or read timeouts when calling the webservice. Strangely, the access.log of the service shows part of the request or the response instead of the URL. It looks like this (looks like the end of the request string) x.x.x.x -> y.y.y.y:8080 - - [timestamp] "POST /webservice HTTP/1.0" 200 16127 0 x.x.x.x -> y.y.y.y:8080 - - [timestamp] "POST /webservice HTTP/1.0" 200 22511 1 x.x.x.x -> y.y.y.y:8080 - - [timestamp] "il=\"true\"/><nsl:text xsi:type=\"xsd:string\" xsi:nil=\"true\"/></SOAPSomeOperation></soapenv:Body></soapenv:Envelope> Axis/1.4" 400 299 0 or (some string out of the what looks like the request) x.x.x.x -> y.y.y.y:8080 - - [timestamp] ":string\">some text</sometag><othertag>moretext" 400 299 0 or in some other cases it looks like two requests thrown together (... means xml string left out): x.x.x.x -> y.y.y.y:8080 - - [timestamp] "...</someop></soapenv:Body></soapenv:Envelope>:xsd=\"http://www.w3.org/2001/XMLSchema\"...</soapenv:Body></soapenv:Envelope>" 400 299 0 Application log does not give any hints. Frequency of such call is 1% of all calls to that service. The only discriminator I know of so far is that it happens since operations informed us that the service url changed because of "server migration". Has anyone experienced such phenomenon yet? Has somebody got an idea whats wrong and how to fix? Thanks,

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• Unknown error sourcing a script containing 'typeset -r' wrapped in command substitution

  - by Bernard Assaf

  I wish to source a script, print the value of a variable this script defines, and then have this value be assigned to a variable on the command line with command substitution wrapping the source/print commands. This works on ksh88 but not on ksh93 and I am wondering why. $ cat typeset_err.ksh #!/bin/ksh unset _typeset_var typeset -i -r _typeset_var=1 DIR=init # this is the variable I want to print When run on ksh88 (in this case, an AIX 6.1 box), the output is as follows: $ A=$(. ./typeset_err.ksh; print $DIR) $ echo $A init When run on ksh93 (in this case, a Linux machine), the output is as follows: $ A=$(. ./typeset_err.ksh; print $DIR) -ksh: _typeset_var: is read only $ print $A ($A is undefined) The above is just an example script. The actual thing I wish to accomplish is to source a script that sets values to many variables, so that I can print just one of its values, e.g. $DIR, and have $A equal that value. I do not know in advance the value of $DIR, but I need to copy files to $DIR during execution of a different batch script. Therefore the idea I had was to source the script in order to define its variables, print the one I wanted, then have that print's output be assigned to another variable via $(...) syntax. Admittedly a bit of a hack, but I don't want to source the entire sub-script in the batch script's environment because I only need one of its variables. The typeset -r code in the beginning is the error. The script I'm sourcing contains this in order to provide a semaphore of sorts--to prevent the script from being sourced more than once in the environment. (There is an if statement in the real script that checks for _typeset_var = 1, and exits if it is already set.) So I know I can take this out and get $DIR to print fine, but the constraints of the problem include keeping the typeset -i -r. In the example script I put an unset in first, to ensure _typeset_var isn't already defined. By the way I do know that it is not possible to unset a typeset -r variable, according to ksh93's man page for ksh. There are ways to code around this error. The favorite now is to not use typeset, but just set the semaphore without typeset (e.g. _typeset_var=1), but the error with the code as-is remains as a curiosity to me, and I want to see if anyone can explain why this is happening. By the way, another idea I abandoned was to grep the variable I need out of its containing script, then print that one variable for $A to be set to; however, the variable ($DIR in the example above) might be set to another variable's value (e.g. DIR=$dom/init), and that other variable might be defined earlier in the script; therefore, I need to source the entire script to make sure I all variables are defined so that $DIR is correctly defined when sourcing.

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• jqGrid : "All in One" approach width jqGridEdit Class > how to set a composite primary key ?

  - by Qualliarys

  Hello, How to set a composite primary key for a "All in One" approach (grid defined in JS file, and data using jqGridEdit Class in php file) ? Please, for me a composite primary key of a table T, is a elementary primary key that is defined with some fields belong to this table T ! Here is my test, but i get no data and cannot use the CRUD operations : In my JS file i have this lines code: ... colModel":[ {"name":"index","index":"index","label":"index"}, // <= THAT'S JUST THE INDEX OF MY TABLE {"name":"user","index":"user","label":"user","key":true}, // <= A PART OF MY COMPOSITE PRIMARY KEY {"name":"pwd","index":"pwd","label":"pwd","key":true}, // <= A PART OF MY COMPOSITE PRIMARY KEY {"name":"state","index":"state","label":"state","key":true}, // <= A PART OF MY COMPOSITE PRIMARY KEY ... <= AND SO ON "url":"mygrid_crud.php", "datatype":"json", "jsonReader":{repeatitems:false}, "editurl": "mygrid_crud.php", "prmNames":{"id":"index"} // <= WHAT I NEED TO WRITE HERE ??? ... In my php file (mygrid_crud.php) : ... $grid = new jqGridEdit($conn); $query = "SELECT * FROM mytable WHERE user='$user' and pwd='$pwd' and state='$state'..."; // <= SELECT * it's ok or i need to specify all fields i need ? $grid->SelectCommand = $query; $grid->dataType = "json"; $grid->table = 'mytable'; $grid->setPrimaryKeyId('index'); // <= WHAT I NEED TO WRITE HERE ??? ... $grid->editGrid(); Please, say me what is wrong, and how to do to set a composite primary key in this approach !? Thank you so much for tour responses.

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• Understanding F# Asynchronous Programming

  - by Yin Zhu

  I kind of know the syntax of asynchronous programming in F#. E.g. let downloadUrl(url:string) = async { let req = HttpWebRequest.Create(url) // Run operation asynchronously let! resp = req.AsyncGetResponse() let stream = resp.GetResponseStream() // Dispose 'StreamReader' when completed use reader = new StreamReader(stream) // Run asynchronously and then return the result return! reader.AsyncReadToEnd() } In F# expert book (and many other sources), they say like let! var = expr simply means "perform the asynchronous operation expr and bind the result to var when the operation completes. Then continue by executing the rest of the computation body" I also know that a new thread is created when performing async operation. My original understanding was that there are two parallel threads after the async operation, one doing I/O and one continuing to execute the async body at the same time. But in this example, I am confused at let! resp = req.AsyncGetResponse() let stream = resp.GetResponseStream() What happens if resp has not started yet and the thread in the async body wants to GetResponseStream? Is this a possible error? So maybe my original understanding was wrong. The quoted sentences in the F# expert book actually means that "creating a new thread, hang the current thread up, when the new thread finishes, wake up the body thread and continue", but in this case I don't see we could save any time. In the original understanding, the time is saved when there are several independent IO operations in one async block so that they could be done at the same time without intervention with each other. But here, if I don't get the response, I cannot create the stream; only I have stream, I can start reading the stream. Where's the time gained?

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• Asynchronous event loop design and issues.

  - by Artyom

  Hello, I'm designing event loop for asynchronous socket IO using epoll/devpoll/kqueue/poll/select (including windows-select). I have two options of performing, IO operation: Non-blocking mode, poll on EAGAIN Set socket to non-blocking mode. Read/Write to socket. If operation succeeds, post completion notification to event loop. If I get EAGAIN, add socket to "select list" and poll socket. Polling mode: poll and then execute Add socket to select list and poll it. Wait for notification that it is readable writable read/write Post completion notification to event loop of sucseeds To me it looks like first would require less system calls when using in normal mode, especially for writing to socket (buffers are quite big). Also it looks like that it would be possible to reduce the overhead over number of "select" executions, especially it is nice when you do not have something that scales well as epoll/devpoll/kqueue. Questions: Are there any advantages of the second approach? Are there any portability issues with non-blocking operations on sockets/file descriptors over numerous operating systems: Linux, FreeBSD, Solaris, MacOSX, Windows. Notes: Please do not suggest using existing event-loop/socket-api implementations

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• How do I test database-related code with NUnit?

  - by Michael Haren

  I want to write unit tests with NUnit that hit the database. I'd like to have the database in a consistent state for each test. I thought transactions would allow me to "undo" each test so I searched around and found several articles from 2004-05 on the topic: http://weblogs.asp.net/rosherove/archive/2004/07/12/180189.aspx http://weblogs.asp.net/rosherove/archive/2004/10/05/238201.aspx http://davidhayden.com/blog/dave/archive/2004/07/12/365.aspx http://haacked.com/archive/2005/12/28/11377.aspx These seem to resolve around implementing a custom attribute for NUnit which builds in the ability to rollback DB operations after each test executes. That's great but... Does this functionality exists somewhere in NUnit natively? Has this technique been improved upon in the last 4 years? Is this still the best way to test database-related code? Edit: it's not that I want to test my DAL specifically, it's more that I want to test pieces of my code that interact with the database. For these tests to be "no-touch" and repeatable, it'd be awesome if I could reset the database after each one. Further, I want to ease this into an existing project that has no testing place at the moment. For that reason, I can't practically script up a database and data from scratch for each test.

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• Asp.Net Login Control very slow initial connection to Non-Trusted AD Domain

  - by Eric Brown - Cal

  ASP.NET Login control is very slow making the initial connection to AD when authenticating to a different domain than the domain the web server is a member of. Problem occurs for the IIS server and when using with the Visual Studio's built in web server. It takes about 30 seconds the first time when attempting to use the control to connect against another domain. There is no trust relationship bewteen the web server's domain and the other domains (attempted connecting to several different domains). Subsequent connections execute quickly until the connection times out. Using Systernals Process Monitor to troubleshoot, there are two OpenQuery operations right before the delay to "C:\WINDOWS\asembly\GAC_MSIL\System.DirectoryServices\2.0.0.0_b03f5f7f11d50a3a\Netapi32.dll with a result NAME NOT FOUND" and right after the 30 second delay the TCP Send and TCP Recieves indicate communication begins with the AD server. Things we have tried: Impersonating an administrator on the web server in the web.config; Granting permissions to the CryptoKeys to the NetworkService and ASPNET; Specifying by IP instead of DNS name; Multiple variations of specifying the name and ldap server with domains and OU's; Local host entries; Looked for ports being blocked (SYN_SENT) with netstat -an. Nslookup resolves all the domains and systems involved correectly. TraceRt shows the Correct routes Any Idea or hints are greately appreicated.

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• F# List SelectMany

  - by Tuomas Hietanen

  This is quite simple question but I didn't find an answer: Is there any Seq/List operation in F# to match the LINQ SelectMany? I know I can use System.Linq in F# if I want to. I know I can make a recursive method and use F# Computation Expressions (and make even more powerful things). But if I try to prove that F# List operations are more powerful than LINQ... .Where = List.filter .Select = List.map .Aggregate = List.fold ... In C# SelectMany usage syntax is pretty simple: var flattenedList = from i in items1 from j in items2 select ... Is there any easy direct match, List.flatten, List.bind or something like that? SelectMany has a couple of signatures, but the most complex one seems to be: IEnumerable<TResult> SelectMany<TSource, TCollection, TResult>( this IEnumerable<TSource> source, Func<TSource, IEnumerable<TCollection>> collectionSelector, Func<TSource, TCollection, TResult> resultSelector ); In F# terms this would be: ('a -> 'b list) -> ('a -> 'b -> 'c) -> 'a list -> 'c list

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• Creating a REST client API using Reactive Extensions (Rx)

  - by Jonas Follesø

  I'm trying to get my head around the right use cases for Reactive Extensions (Rx). The examples that keeps coming up are UI events (drag and drop, drawing), and suggestions that Rx is suitable for asynchronous applications/operations such as web service calls. I'm working on an application where I need to write a tiny client API for a REST service. I need to call four REST end-points, three to get some reference data (Airports, Airlines, and Statuses), and the fourth is the main service that will give you flight times for a given airport. I have created classes exposing the three reference data services, and the methods look something like this: public Observable<Airport> GetAirports() public Observable<Airline> GetAirlines() public Observable<Status> GetStatuses() public Observable<Flights> GetFlights(string airport) In my GetFlights method I want each Flight to hold a reference the Airport it's departing from, and the Airline operating the flight. To do that I need the data from GetAirports and GetAirlines to be available. My initial thinking was something like this: Write a Rx Query that will Subscribe on the three reference services (Airports, Airlines and Statuses) Add results into a Dictionary (airline code and Airline object) When all three GetAirports, GetAirlines and GetStatuses are complete, then return the GetFlights IObservable. Is this a reasonable scenario for Rx? I'm developing on the Windows Phone 7, so I'm not sure if there are major differences in the Rx implementations across the different platforms.

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• [Zend YouTubeAPP] failed to upgrade a token

  - by kwokwai

  Hi all, I was testing Zend Gdata 1.10.1 in my localhost. I downloaded Zend Gdate from this link: http://framework.zend.com/download/webservices Inside the Zend Gdata zip file, there was a folder called demos. I extracted it and used the YouTudeVideoApp to upload a sample video to Youtube. But every time after I logged into Youtube, before it redirected me to my localhost, I received a warning message like this warning message: localhost: This website is registered with Google to make authorization requests, but has not been configured to send requests securely. We recommend that you continue the process only if you trust the following destination: localhost:8080/youtube/operations.php So I googled on how to resolve the problem of getting this warning message when I saw some people suggesed changing the value of $secure to True in operation.php. Here is the script mentioned: function generateAuthSubRequestLink($nextUrl = null) { $scope = 'http://gdata.youtube.com'; $secure = true; $session = true; if (!$nextUrl) { generateUrlInformation(); $nextUrl = $_SESSION['operationsUrl']; } $url = Zend_Gdata_AuthSub::getAuthSubTokenUri($nextUrl, $scope, $secure, $session); echo '<a href="' . $url . '"><strong>Click here to authenticate with YouTube</strong></a>'; } After I altered the value of $secure to True, I found that the warning message changed to this: localhost: Registered, secure. This website is registered with Google to make authorization requests The new warning message is somehow shorter and looks better than the previous warning message. But once I pressed the Allow Access button, it turned out to be this: ERROR - Token upgrade for CI3M6_Q3EOGkxoL-___wEYjffToQQ failed : Token upgrade failed. Reason: Invalid AuthSub header. Error 401 ERROR - Unknown search type - '' I don't know why this happened. Could you help me solve the problem please?

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• Correct initialization sequence for Linux serial port

  - by whitequark

  I wrote an application that must use serial ports on Linux, especially ttyUSB ones. Reading and writing operations are performed with standard select()/read() loop and write(), and there is probably nothing wrong in them, but initialization code (or absence of some part of it) damages something in the tty subsystem. Here it is: vuxboot(string filename, unsigned baud = B115200) : _debug(false) { _fd = open(filename.c_str(), O_RDWR | O_NOCTTY); if(!_fd) throw new io_error("cannot open port"); // Serial initialization was written with FTDI USB-to-serial converters // in mind. Anyway, who wants to use non-8n1 protocol? tcgetattr(_fd, &_termios); termios tio = {0}; tio.c_iflag = IGNPAR; tio.c_oflag = 0; tio.c_cflag = baud | CLOCAL | CREAD | CS8; tio.c_lflag = 0; tcflush(_fd, TCIFLUSH); tcsetattr(_fd, TCSANOW, &tio); } Another tcsetattr(_fd, TCSANOW, &_termios) sits in the destructor, but it is irrelevant. With or without this termios initialization, strange things happen in system after the application exits. Sometimes plain cat (or hd) exits immediately printing nothing or same stuff each time, sometimes it is waiting and not displaying any of the data that is surely sent onto the port; and close() (read() too, but not every time) emits a strange WARNING to dmesg referring to usb-serial.c. I checked the hardware and firmware tens of times (even on different machines) and I am sure it is working as intended; moreover, I stripped the firmware to just print same message over and over. How can I use serial port without destroying anything? Thanks.

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• NSUndoManager, Core Data and selective undo/redo

  - by Combat

  I'm working on a core data application that has a rather large hierarchy of managed objects similar to a tree. When a base object is created, it creates a few child objects which in turn create their own child objects and so on. Each of these child objects may gather information using NSURLConnections. Now, I'd like to support undo/redo with the undoManager in the managedObjectContext. The problem is, if a user creates a base object, then tries to undo that action, the base object is not removed. Instead, one or more of the child objects may be removed. Obviously this type of action is unpredictable and unwanted. So I tried disabling undo registration by default. I did this by calling disableUndoRegistration: before anything is modified in the managedObjectContext. Then, enabling undo registration before base operations such as creating a base object the again re-disabling registrations afterwords. Now when i try to undo, I get this error: undo: NSUndoManager 0x1026428b0 is in invalid state, undo was called with too many nested undo groups Thoughts?

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• Insert MANY key value pairs fast into berkeley db with hash access

  - by Kungi

  Hi, i'm trying to build a hash with berkeley db, which shall contain many tuples (approx 18GB of key value pairs), but in all my tests the performance of the insert operations degrades drastically over time. I've written this script to test the performance: #include<iostream> #include<db_cxx.h> #include<ctime> #define MILLION 1000000 int main () { long long a = 0; long long b = 0; int passes = 0; int i = 0; u_int32_t flags = DB_CREATE; Db* dbp = new Db(NULL,0); dbp->set_cachesize( 0, 1024 * 1024 * 1024, 1 ); int ret = dbp->open( NULL, "test.db", NULL, DB_HASH, flags, 0); time_t time1 = time(NULL); while ( passes < 100 ) { while( i < MILLION ) { Dbt key( &a, sizeof(long long) ); Dbt data( &b, sizeof(long long) ); dbp->put( NULL, &key, &data, 0); a++; b++; i++; } DbEnv* dbep = dbp->get_env(); int tmp; dbep->memp_trickle( 50, &tmp ); i=0; passes++; std::cout << "Inserted one million --> pass: " << passes << " took: " << time(NULL) - time1 << "sec" << std::endl; time1 = time(NULL); } } Perhaps you can tell me why after some time the "put" operation takes increasingly longer and maybe how to fix this. Thanks for your help, Andreas

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• Using bitwise operators on > 32 bit integers

  - by dqhendricks

  I am using bitwise operations in order to represent many access control flags within one integer. ADMIN_ACCESS = 1; EDIT_ACCOUNT_ACCESS = 2; EDIT_ORDER_ACCESS = 4; var myAccess = 3; // ie: ( ADMIN_ACCESS | EDIT_ACCOUNT_ACCESS ) if ( myAccess & EDIT_ACCOUNT_ACCESS ) { // check for correct access // allow for editing of account } Most of this is occurring on the PHP side of my project. There is one piece however where Javascript is used to join several access flags using | when saving someone's access level. This works fine to a point. I have found that once an integer (flag) gets too large ( 32bit), it no longer works correctly with bitwise operators in Javascript. For instance: alert( 4294967296 | 1 ); // equals 1, but should equal 4294967297 I am trying to find a workaround for this so that I do not have to limit my number of access control flags to 32. Each access control flag is two times the previous control flag so that each control flag will not interfere with other control flags. dec(4) = bin(100) dec(8) = bin(1000) dec(16) = bin(10000) I have noticed that when adding two of these flags together with a simple +, it seems to come out with the same answer as a bitwise or operation, but am having trouble wrapping my head around whether this is a simple substitution, or if there might be problems with doing this. Can anyone comment on the validity of this workaround? Example: (4294967296 | 262144 | 524288) == (4294967296 + 262144 + 524288)

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• How to host WCF service and TCP server on same socket?

  - by Ole Jak

  Tooday I use ServiceHost for self hosting WCF cervices. I want to host near to my WCF services my own TCP programm for direct sockets operations (like lien to some sort of broadcasting TCP stream) I need control over namespaces (so I would be able to let my clients to send TCP streams directly into my service using some nice URLs like example.com:port/myserver/stream?id=1 or example.com:port/myserver/stream?id=anything and so that I will not be bothered with Idea of 1 client for 1 socket at one time moment, I realy want to keep my WCF services on the same port as my own server or what it is so to be able to call www.example.com:port/myWCF/stream?id=222...) Can any body please help me with this? I am using just WCF now. And I do not enjoy how it works. That is one of many resons why I want to start migration to clear TCP=) I can not use net-tcp binding or any sort of other cool WS-* binding (tooday I use the simpliest one so that my clients like Flash, AJAX, etc connect to me with ease). I needed Fast and easy in implemrnting connection protocol like one I created fore use with Sockets for real time hi ammount of data transfering. So.. Any Ideas? Please - I need help.

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• Displaying progressbar using threading in win 32 applicaition!

  - by kiddo

  In my application I have a simple module were I will read files for some process that will take few seconds..so I thought of displaying a progress bar(using worker thread) while the files are in progress.I have created a thread (code shown below) and also I designed a dialog window with progress control.I used the function MyThreadFunction below to display the progressbar but it just shows only one time and disappears,I am not sure how to make it work.I tried my best inspite of the fact that I am new to threading. reading files void ReadMyFiles() { for(int i = 0; i < fileCount ; fileCount++) { CWinThread* myThread = AfxBeginThread((AFX_THREADPROC)MyThreadFunction,NULL); tempState = *(checkState + index); if(tempCheckState == NOCHECKBOX) { //my operations } else//CHECKED or UNCHECKED { //myoperation } myThread->PostThreadMessage(WM_QUIT,NULL,NULL); } } thread functions UINT MyThreadFunction(LPARAM lparam) { HWND dialogWnd = CreateWindowEx(0,WC_DIALOG,L"Proccessing...",WS_OVERLAPPEDWINDOW|WS_VISIBLE, 600,300,280,120,NULL,NULL,NULL,NULL); HWND pBarWnd = CreateWindowEx(NULL,PROGRESS_CLASS,NULL,WS_CHILD|WS_VISIBLE|PBS_MARQUEE,40,20,200,20, dialogWnd,(HMENU)IDD_PROGRESS,NULL,NULL); MSG msg; PostMessage( pBarWnd, PBM_SETRANGE, 0, MAKELPARAM( 0, 100 ) ); PostMessage(pBarWnd,PBM_SETPOS,0,0); while(PeekMessage(&msg,NULL,NULL,NULL,PM_NOREMOVE)) { if(msg.message == WM_QUIT) { DestroyWindow(dialogWnd); return 1; } AfxGetThread()->PumpMessage(); Sleep(40); } return 1; }

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• Creating a QMainWindow from Java using JNI

  - by ebasconp

  Hi everybody: I'm trying to create a Qt main windows from Java using JNI directly and I got a threading error. My code looks like this: Test class: public class Test { public static void main(String... args) { System.out.println(System.getProperty("java.library.path")); TestWindow f = new TestWindow(); f.show(); } } TestWindow class: public class TestWindow { static { System.loadLibrary("mylib"); } public native void show(); } C++ impl: void JNICALL Java_testpackage_TestWindow_show (JNIEnv *, jobject) { int c = 0; char** a = NULL; QApplication* app = new QApplication(c, a); QMainWindow* mw = new QMainWindow(); mw->setWindowTitle("Hello"); mw->setGeometry(150, 150, 400, 300); mw->show(); QApplication::exec(); } and I get my window painted but frozen (it does not receive any event) and the following error message when instantiating the QMainWindow object: QCoreApplication::sendPostedEvents: Cannot send posted events for objects in another thread I know all the UI operations must done in the UI thread but in my example I created the QApplication in the only thread I have running, so, everything should work properly. I did some tests executing the code of my "show" method from a QMetaObject::invokeMethod stuff using Qt::QueuedConnection but nothing works properly. I know I could use Jambi... but I know that it could be done natively too and that is what I want to do :) Any ideas on this? Thanks in advance! Ernesto

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• asp.net mvc: What is the correct way to return html from controller to refresh select list?

  - by Mark Redman

  Hi, I am new to ASP.NET MVC, particularly ajax operations. I have a form with a jquery dialog for adding items to a drop-down list. This posts to the controller action. If nothing (ie void method) is returned from the Controller Action the page returns having updated the database, but obviously there no chnage to the form. What would be the best practice in updating the drop down list with the added id/value and selecting the item. I think my options are: 1) Construct and return the html manually that makes up the new <select> tag [this would be easy enough and work, but seems like I am missing something] 2) Use some kind of "helper" to construct the new html [This seems to make sense] 3) Only return the id/value and add this to the list and select the item [This seems like an overkill considering the item needs to be placed in the correct order etc] 4) Use some kind of Partial View [Does this mean creating additional forms within ascx controls? not sure how this would effect submitting the main form its on? Also unless this is reusable by passing in parameters(not sure how thats done) maybe 2 is the option?] UPDATE: Having looked around a bit, it seems that generating html withing the controller is not a good idea. I have seen other posts that render partialviews to strings which I guess is what I need and separates concerns (since the html bits are in the ascx). Any comments on whether that is good practice.

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