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• Using TPL and PLINQ to raise performance of feed aggregator

  - by DigiMortal

  In this posting I will show you how to use Task Parallel Library (TPL) and PLINQ features to boost performance of simple RSS-feed aggregator. I will use here only very basic .NET classes that almost every developer starts from when learning parallel programming. Of course, we will also measure how every optimization affects performance of feed aggregator. Feed aggregator Our feed aggregator works as follows: Load list of blogs Download RSS-feed Parse feed XML Add new posts to database Our feed aggregator is run by task scheduler after every 15 minutes by example. We will start our journey with serial implementation of feed aggregator. Second step is to use task parallelism and parallelize feeds downloading and parsing. And our last step is to use data parallelism to parallelize database operations. We will use Stopwatch class to measure how much time it takes for aggregator to download and insert all posts from all registered blogs. After every run we empty posts table in database. Serial aggregation Before doing parallel stuff let’s take a look at serial implementation of feed aggregator. All tasks happen one after other. internal class FeedClient {     private readonly INewsService _newsService;     private const int FeedItemContentMaxLength = 255;       public FeedClient()     {          ObjectFactory.Initialize(container =>          {              container.PullConfigurationFromAppConfig = true;          });           _newsService = ObjectFactory.GetInstance<INewsService>();     }       public void Execute()     {         var blogs = _newsService.ListPublishedBlogs();           for (var index = 0; index <blogs.Count; index++)         {              ImportFeed(blogs[index]);         }     }       private void ImportFeed(BlogDto blog)     {         if(blog == null)             return;         if (string.IsNullOrEmpty(blog.RssUrl))             return;           var uri = new Uri(blog.RssUrl);         SyndicationContentFormat feedFormat;           feedFormat = SyndicationDiscoveryUtility.SyndicationContentFormatGet(uri);           if (feedFormat == SyndicationContentFormat.Rss)             ImportRssFeed(blog);         if (feedFormat == SyndicationContentFormat.Atom)             ImportAtomFeed(blog);                 }       private void ImportRssFeed(BlogDto blog)     {         var uri = new Uri(blog.RssUrl);         var feed = RssFeed.Create(uri);           foreach (var item in feed.Channel.Items)         {             SaveRssFeedItem(item, blog.Id, blog.CreatedById);         }     }       private void ImportAtomFeed(BlogDto blog)     {         var uri = new Uri(blog.RssUrl);         var feed = AtomFeed.Create(uri);           foreach (var item in feed.Entries)         {             SaveAtomFeedEntry(item, blog.Id, blog.CreatedById);         }     } } Serial implementation of feed aggregator downloads and inserts all posts with 25.46 seconds. Task parallelism Task parallelism means that separate tasks are run in parallel. You can find out more about task parallelism from MSDN page Task Parallelism (Task Parallel Library) and Wikipedia page Task parallelism. Although finding parts of code that can run safely in parallel without synchronization issues is not easy task we are lucky this time. Feeds import and parsing is perfect candidate for parallel tasks. We can safely parallelize feeds import because importing tasks doesn’t share any resources and therefore they don’t also need any synchronization. After getting the list of blogs we iterate through the collection and start new TPL task for each blog feed aggregation. internal class FeedClient {     private readonly INewsService _newsService;     private const int FeedItemContentMaxLength = 255;       public FeedClient()     {          ObjectFactory.Initialize(container =>          {              container.PullConfigurationFromAppConfig = true;          });           _newsService = ObjectFactory.GetInstance<INewsService>();     }       public void Execute()     {         var blogs = _newsService.ListPublishedBlogs();                var tasks = new Task[blogs.Count];           for (var index = 0; index <blogs.Count; index++)         {             tasks[index] = new Task(ImportFeed, blogs[index]);             tasks[index].Start();         }           Task.WaitAll(tasks);     }       private void ImportFeed(object blogObject)     {         if(blogObject == null)             return;         var blog = (BlogDto)blogObject;         if (string.IsNullOrEmpty(blog.RssUrl))             return;           var uri = new Uri(blog.RssUrl);         SyndicationContentFormat feedFormat;           feedFormat = SyndicationDiscoveryUtility.SyndicationContentFormatGet(uri);           if (feedFormat == SyndicationContentFormat.Rss)             ImportRssFeed(blog);         if (feedFormat == SyndicationContentFormat.Atom)             ImportAtomFeed(blog);                }       private void ImportRssFeed(BlogDto blog)     {          var uri = new Uri(blog.RssUrl);          var feed = RssFeed.Create(uri);           foreach (var item in feed.Channel.Items)          {              SaveRssFeedItem(item, blog.Id, blog.CreatedById);          }     }     private void ImportAtomFeed(BlogDto blog)     {         var uri = new Uri(blog.RssUrl);         var feed = AtomFeed.Create(uri);           foreach (var item in feed.Entries)         {             SaveAtomFeedEntry(item, blog.Id, blog.CreatedById);         }     } } You should notice first signs of the power of TPL. We made only minor changes to our code to parallelize blog feeds aggregating. On my machine this modification gives some performance boost – time is now 17.57 seconds. Data parallelism There is one more way how to parallelize activities. Previous section introduced task or operation based parallelism, this section introduces data based parallelism. By MSDN page Data Parallelism (Task Parallel Library) data parallelism refers to scenario in which the same operation is performed concurrently on elements in a source collection or array. In our code we have independent collections we can process in parallel – imported feed entries. As checking for feed entry existence and inserting it if it is missing from database doesn’t affect other entries the imported feed entries collection is ideal candidate for parallelization. internal class FeedClient {     private readonly INewsService _newsService;     private const int FeedItemContentMaxLength = 255;       public FeedClient()     {          ObjectFactory.Initialize(container =>          {              container.PullConfigurationFromAppConfig = true;          });           _newsService = ObjectFactory.GetInstance<INewsService>();     }       public void Execute()     {         var blogs = _newsService.ListPublishedBlogs();                var tasks = new Task[blogs.Count];           for (var index = 0; index <blogs.Count; index++)         {             tasks[index] = new Task(ImportFeed, blogs[index]);             tasks[index].Start();         }           Task.WaitAll(tasks);     }       private void ImportFeed(object blogObject)     {         if(blogObject == null)             return;         var blog = (BlogDto)blogObject;         if (string.IsNullOrEmpty(blog.RssUrl))             return;           var uri = new Uri(blog.RssUrl);         SyndicationContentFormat feedFormat;           feedFormat = SyndicationDiscoveryUtility.SyndicationContentFormatGet(uri);           if (feedFormat == SyndicationContentFormat.Rss)             ImportRssFeed(blog);         if (feedFormat == SyndicationContentFormat.Atom)             ImportAtomFeed(blog);                }       private void ImportRssFeed(BlogDto blog)     {         var uri = new Uri(blog.RssUrl);         var feed = RssFeed.Create(uri);           feed.Channel.Items.AsParallel().ForAll(a =>         {             SaveRssFeedItem(a, blog.Id, blog.CreatedById);         });      }        private void ImportAtomFeed(BlogDto blog)      {         var uri = new Uri(blog.RssUrl);         var feed = AtomFeed.Create(uri);           feed.Entries.AsParallel().ForAll(a =>         {              SaveAtomFeedEntry(a, blog.Id, blog.CreatedById);         });      } } We did small change again and as the result we parallelized checking and saving of feed items. This change was data centric as we applied same operation to all elements in collection. On my machine I got better performance again. Time is now 11.22 seconds. Results Let’s visualize our measurement results (numbers are given in seconds). As we can see then with task parallelism feed aggregation takes about 25% less time than in original case. When adding data parallelism to task parallelism our aggregation takes about 2.3 times less time than in original case. More about TPL and PLINQ Adding parallelism to your application can be very challenging task. You have to carefully find out parts of your code where you can safely go to parallel processing and even then you have to measure the effects of parallel processing to find out if parallel code performs better. If you are not careful then troubles you will face later are worse than ones you have seen before (imagine error that occurs by average only once per 10000 code runs). Parallel programming is something that is hard to ignore. Effective programs are able to use multiple cores of processors. Using TPL you can also set degree of parallelism so your application doesn’t use all computing cores and leaves one or more of them free for host system and other processes. And there are many more things in TPL that make it easier for you to start and go on with parallel programming. In next major version all .NET languages will have built-in support for parallel programming. There will be also new language constructs that support parallel programming. Currently you can download Visual Studio Async to get some idea about what is coming. Conclusion Parallel programming is very challenging but good tools offered by Visual Studio and .NET Framework make it way easier for us. In this posting we started with feed aggregator that imports feed items on serial mode. With two steps we parallelized feed importing and entries inserting gaining 2.3 times raise in performance. Although this number is specific to my test environment it shows clearly that parallel programming may raise the performance of your application significantly.

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• How to apply LINQ to ObjectResult<int?> when using EF 4.0?

  - by KentZhou

  Suppose I have a function call from EF like: var result = context.myFunction(); the reuslt type is ObjectResut<int?>. Then I want to use linq to get the single value. How to write the linq?

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• How to calculate sum of a DataTable's Column in LINQ (to Dataset)?

  - by rivera.reyrivera

  I'm just started to read up on LINQ and I want to start incorporating it into my code. I know how to compute the sum of a DataTable's column by either "Foreach"-ing through the rows or by doing a compute.sum on the specific column. How do I do the equivalent with LINQ to DataSet?

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• Using a Linq-To-SQL class automagically generates the connection string for me; is there a way to ma

  - by Sergio Tapia

  I'm just beginning to use Linq-to-SQL and it's just wonderful to use. The problem is, this software is going to be run on a lot of machines and each machine will have a unique connection string. Is there a way for me to manually set the connection the Linq-to-SQL (.dbml) uses? The way I'm doing things now is creating the .dbml file, and in the graphic designer I'm dragging tables from the Server Explorer to the white board of the .dbml.

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• How to perform group by in LINQ and get a Iqueryable or a Custom Class Object?

  - by VJ

  Here is my query - var data = Goaldata.GroupBy(c => c.GoalId).ToList(); This returns a Igrouping object and I want an Iqueryable object which I can directly query to get the data while in this case I have to loop through using a foreach() and then get the data. Is there another way to group by in LINQ which returns directly a list of Iqueryable or the a List as similar to what happens for order by in LINQ.

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• How is this Nested Set SQL query converted into a LINQ query?

  - by Chad

  Querying a Nested Set Model table, here's the SQL... how can this be written in LINQ? SELECT parent.name FROM nested_category AS node, nested_category AS parent WHERE node.lft BETWEEN parent.lft AND parent.rgt AND node.name = 'FLASH' ORDER BY parent.lft; particularly, the FROM part... never tried to do anything like that in LINQ.

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• [Linq to sql] Is it worth a try as a beginner to an ORM?

  - by Pandiya Chendur

  Thus far used sql server stored procedures for all my web applications... Now thought of moving to an ORM... I would like to ask SO users about LINQ to SQL Is Linq to sql worth a try as a beginner to an ORM? or should i look for someothers... Any suggestion...

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• How to select all parent objects into DataContext using single LINQ query ?

  - by too

  I am looking for an answer to a specific problem of fetching whole LINQ object hierarchy using single SELECT. At first I was trying to fill as much LINQ objects as possible using LoadOptions, but AFAIK this method allows only single table to be linked in one query using LoadWith. So I have invented a solution to forcibly set all parent objects of entity which of list is to be fetched, although there is a problem of multiple SELECTS going to database - a single query results in two SELECTS with the same parameters in the same LINQ context. For this question I have simplified this query to popular invoice example: public static class Extensions { public static IEnumerable<T> ForEach<T>(this IEnumerable<T> collection, Action<T> func) { foreach(var c in collection) { func(c); } return collection; } } public IEnumerable<Entry> GetResults(AppDataContext context, int CustomerId) { return ( from entry in context.Entries join invoice in context.Invoices on entry.EntryInvoiceId equals invoice.InvoiceId join period in context.Periods on invoice.InvoicePeriodId equals period.PeriodId // LEFT OUTER JOIN, store is not mandatory join store in context.Stores on entry.EntryStoreId equals store.StoreId into condStore from store in condStore.DefaultIfEmpty() where (invoice.InvoiceCustomerId = CustomerId) orderby entry.EntryPrice descending select new { Entry = entry, Invoice = invoice, Period = period, Store = store } ).ForEach(x => { x.Entry.Invoice = Invoice; x.Invoice.Period = Period; x.Entry.Store = Store; } ).Select(x => x.Entry); } When calling this function and traversing through result set, for example: var entries = GetResults(this.Context); int withoutStore = 0; foreach(var k in entries) { if(k.EntryStoreId == null) withoutStore++; } the resulting query to database looks like (single result is fetched): SELECT [t0].[EntryId], [t0].[EntryInvoiceId], [t0].[EntryStoreId], [t0].[EntryProductId], [t0].[EntryQuantity], [t0].[EntryPrice], [t1].[InvoiceId], [t1].[InvoiceCustomerId], [t1].[InvoiceDate], [t1].[InvoicePeriodId], [t2].[PeriodId], [t2].[PeriodName], [t2].[PeriodDateFrom], [t4].[StoreId], [t4].[StoreName] FROM [Entry] AS [t0] INNER JOIN [Invoice] AS [t1] ON [t0].[EntryInvoiceId] = [t1].[InvoiceId] INNER JOIN [Period] AS [t2] ON [t2].[PeriodId] = [t1].[InvoicePeriodId] LEFT OUTER JOIN ( SELECT 1 AS [test], [t3].[StoreId], [t3].[StoreName] FROM [Store] AS [t3] ) AS [t4] ON [t4].[StoreId] = ([t0].[EntryStoreId]) WHERE (([t1].[InvoiceCustomerId]) = @p0) ORDER BY [t0].[InvoicePrice] DESC -- @p0: Input Int (Size = 0; Prec = 0; Scale = 0) [186] -- Context: SqlProvider(Sql2008) Model: AttributedMetaModel Build: 3.5.30729.1 SELECT [t0].[EntryId], [t0].[EntryInvoiceId], [t0].[EntryStoreId], [t0].[EntryProductId], [t0].[EntryQuantity], [t0].[EntryPrice], [t1].[InvoiceId], [t1].[InvoiceCustomerId], [t1].[InvoiceDate], [t1].[InvoicePeriodId], [t2].[PeriodId], [t2].[PeriodName], [t2].[PeriodDateFrom], [t4].[StoreId], [t4].[StoreName] FROM [Entry] AS [t0] INNER JOIN [Invoice] AS [t1] ON [t0].[EntryInvoiceId] = [t1].[InvoiceId] INNER JOIN [Period] AS [t2] ON [t2].[PeriodId] = [t1].[InvoicePeriodId] LEFT OUTER JOIN ( SELECT 1 AS [test], [t3].[StoreId], [t3].[StoreName] FROM [Store] AS [t3] ) AS [t4] ON [t4].[StoreId] = ([t0].[EntryStoreId]) WHERE (([t1].[InvoiceCustomerId]) = @p0) ORDER BY [t0].[InvoicePrice] DESC -- @p0: Input Int (Size = 0; Prec = 0; Scale = 0) [186] -- Context: SqlProvider(Sql2008) Model: AttributedMetaModel Build: 3.5.30729.1 The question is why there are two queries and how can I fetch LINQ objects without such hacks?

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• How do I get results from a Linq query in the order of IDs that I provide?

  - by Keltex

  I'm looking to get query results back from Linq in the order that I pass IDs to the query. So it would look something like this: var IDs = new int [] { 5, 20, 10 } var items = from mytable in db.MyTable where IDs.Contains(mytable.mytableID) orderby // not sure what to do here select mytable; I'm hoping to get items in the order of IDs (5, 20, 10). (Note this is similar to this question, but I would like to do it in Linq instead of SQL)

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• How to group methods belong to one entity in one class file in Core Data like Linq?

  - by Siegfried

  How to group methods belong to one entity in one class file in Core Data like Linq? In Linq, we can put all methods in the domain object class and reuse them, in Core Data, is there any way to create different classes for different entities? Or we can only use predicate to retrieve?

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• How many objects can LINQ used to create per second ?

  - by MemoryLeak

  I used Linq to insert objects into database.But if i used threads to simultanously create 20 object within 1 second, then system will fail to add 20 objects into database. And I found it is not because of the sql server 's limit. so the only possible is Linq, any one have idea ? How can I create 20 records or more in 1 second within 1 second ?

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• Can we use Business Objects which we made & data acess Layer of LINQ?

  - by SAHIL SINGLA

  Can we use Business Objects which we made & data acess Layer of LINQ? Because i want to put the validation in Business Objects & also want to use data acess Layer of Linq?

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• What no existing LINQ Providers do you identify needs in the projects you develop?

  - by Poco

  What no existing LINQ Providers do you identify needs in the projects you develop? Attempt at translation: In your development projects, are there LINQ providers you wished existed but do not?

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• iptables rules keep showing up

  - by Omriko

  I just installed an ubuntu precise server, after a few weird communications issues I checked the iptables list and found: Chain INPUT (policy DROP) target prot opt source destination ACCEPT all -- anywhere anywhere ACCEPT all -- anywhere anywhere state RELATED,ESTABLISHED ACCEPT tcp -- 10.0.0.0/24 anywhere tcp spts:1024:65535 dpt:ssh state NEW ACCEPT icmp -- anywhere anywhere state NEW ACCEPT icmp -- anywhere anywhere state NEW ACCEPT icmp -- anywhere anywhere state NEW ACCEPT icmp -- anywhere anywhere state NEW DROP tcp -- anywhere anywhere tcp dpt:10520 state NEW DROP udp -- anywhere anywhere udp spts:1:65535 dpt:31337 state NEW DROP udp -- anywhere anywhere udp spts:1:65535 dpt:31338 state NEW DROP udp -- anywhere anywhere udp spts:1:65535 dpt:54320 state NEW DROP udp -- anywhere anywhere udp spts:1:65535 dpt:54321 state NEW DROP tcp -- anywhere anywhere tcp dpt:12345 state NEW DROP tcp -- anywhere anywhere tcp dpt:12346 state NEW DROP tcp -- anywhere anywhere tcp dpt:20034 state NEW DROP tcp -- anywhere anywhere tcp dpt:16600 state NEW DROP tcp -- anywhere anywhere tcp dpt:16660 state NEW DROP tcp -- anywhere anywhere tcp dpt:65000 state NEW DROP udp -- anywhere anywhere udp dpt:34555 state NEW DROP udp -- anywhere anywhere udp dpt:35555 state NEW DROP udp -- anywhere anywhere udp spts:netbios-ns:netbios-dgm dpts:netbios-ns:netbios-dgm state NEW DROP tcp -- anywhere anywhere tcp spts:1024:65535 dpt:netbios-ssn state NEW DROP tcp -- anywhere anywhere tcp spts:1024:65535 dpt:microsoft-ds state NEW DROP udp -- anywhere anywhere udp spt:microsoft-ds dpt:microsoft-ds state NEW DROP udp -- anywhere anywhere udp spts:1024:65535 dpt:microsoft-ds state NEW DROP tcp -- anywhere anywhere tcp spts:1024:65535 dpt:loc-srv state NEW DROP tcp -- anywhere anywhere tcp spts:1024:65535 dpt:5000 state NEW DROP tcp -- anywhere anywhere tcp spts:1024:65535 dpts:1025:1029 state NEW DROP udp -- anywhere anywhere udp spts:1:65535 dpt:loc-srv state NEW ACCEPT tcp -- anywhere anywhere tcp spts:1024:65535 dpt:28082 state NEW DROP all -- anywhere anywhere state NEW Chain FORWARD (policy DROP) target prot opt source destination Chain OUTPUT (policy DROP) target prot opt source destination ACCEPT all -- anywhere anywhere ACCEPT all -- anywhere anywhere state RELATED,ESTABLISHED ACCEPT tcp -- anywhere anywhere tcp spts:tcpmux:65535 dpts:tcpmux:65535 state NEW ACCEPT udp -- anywhere anywhere udp dpts:1:65535 state NEW ACCEPT icmp -- anywhere anywhere state NEW ACCEPT tcp -- anywhere anywhere tcp spts:1024:65535 dpt:28082 state NEW DROP all -- anywhere anywhere state NEW I tried to wipe the rules, I disabled UFW, Ive rewritten and saved iptables rules according to this guide, but every minute or so the old rules return.... I checked crontab for scheduled tasks, there is nothing in there but still these rules appear every minute... please help!

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• C# Multiple Property Sort

  - by Ben Griswold

  As you can see in the snippet below, sorting is easy with Linq.  Simply provide your OrderBy criteria and you’re done.  If you want a secondary sort field, add a ThenBy expression to the chain.  Want a third level sort?  Just add ThenBy along with another sort expression. var projects = new List<Project>     {         new Project {Description = "A", ProjectStatusTypeId = 1},         new Project {Description = "B", ProjectStatusTypeId = 3},         new Project {Description = "C", ProjectStatusTypeId = 3},         new Project {Description = "C", ProjectStatusTypeId = 2},         new Project {Description = "E", ProjectStatusTypeId = 1},         new Project {Description = "A", ProjectStatusTypeId = 2},         new Project {Description = "C", ProjectStatusTypeId = 4},         new Project {Description = "A", ProjectStatusTypeId = 3}     };   projects = projects     .OrderBy(x => x.Description)     .ThenBy(x => x.ProjectStatusTypeId)     .ToList();   foreach (var project in projects) {     Console.Out.WriteLine("{0} {1}", project.Description,         project.ProjectStatusTypeId); } Linq offers a great sort solution most of the time, but what if you want or need to do it the old fashioned way? projects.Sort ((x, y) =>         Comparer<String>.Default             .Compare(x.Description, y.Description) != 0 ?         Comparer<String>.Default             .Compare(x.Description, y.Description) :         Comparer<Int32>.Default             .Compare(x.ProjectStatusTypeId, y.ProjectStatusTypeId));   foreach (var project in projects) {     Console.Out.WriteLine("{0} {1}", project.Description,         project.ProjectStatusTypeId); } It’s not that bad, right? Just for fun, let add some additional logic to our sort.  Let’s say we wanted our secondary sort to be based on the name associated with the ProjectStatusTypeId.  projects.Sort((x, y) =>        Comparer<String>.Default             .Compare(x.Description, y.Description) != 0 ?        Comparer<String>.Default             .Compare(x.Description, y.Description) :        Comparer<String>.Default             .Compare(GetProjectStatusTypeName(x.ProjectStatusTypeId),                 GetProjectStatusTypeName(y.ProjectStatusTypeId)));   foreach (var project in projects) {     Console.Out.WriteLine("{0} {1}", project.Description,         GetProjectStatusTypeName(project.ProjectStatusTypeId)); } The comparer will now consider the result of the GetProjectStatusTypeName and order the list accordingly.  Of course, you can take this same approach with Linq as well.

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• Creating New Scripts Dynamically in Lua

  - by bazola

  Right now this is just a crazy idea that I had, but I was able to implement the code and get it working properly. I am not entirely sure of what the use cases would be just yet. What this code does is create a new Lua script file in the project directory. The ScriptWriter takes as arguments the file name, a table containing any arguments that the script should take when created, and a table containing any instance variables to create by default. My plan is to extend this code to create new functions based on inputs sent in during its creation as well. What makes this cool is that the new file is both generated and loaded dynamically on the fly. Theoretically you could get this code to generate and load any script imaginable. One use case I can think of is an AI that creates scripts to map out it's functions, and creates new scripts for new situations or environments. At this point, this is all theoretical, though. Here is the test code that is creating the new script and then immediately loading it and calling functions from it: function Card:doScriptWriterThing() local scriptName = "ScriptIAmMaking" local scripter = scriptWriter:new(scriptName, {"argumentName"}, {name = "'test'", one = 1}) scripter:makeFileForLoadedSettings() local loadedScript = require (scriptName) local scriptInstance = loadedScript:new("sayThis") print(scriptInstance:get_name()) --will print test print(scriptInstance:get_one()) -- will print 1 scriptInstance:set_one(10000) print(scriptInstance:get_one()) -- will print 10000 print(scriptInstance:get_argumentName()) -- will print sayThis scriptInstance:set_argumentName("saySomethingElse") print(scriptInstance:get_argumentName()) --will print saySomethingElse end Here is ScriptWriter.lua local ScriptWriter = {} local twoSpaceIndent = " " local equalsWithSpaces = " = " local newLine = "\n" --scriptNameToCreate must be a string --argumentsForNew and instanceVariablesToCreate must be tables and not nil function ScriptWriter:new(scriptNameToCreate, argumentsForNew, instanceVariablesToCreate) local instance = setmetatable({}, { __index = self }) instance.name = scriptNameToCreate instance.newArguments = argumentsForNew instance.instanceVariables = instanceVariablesToCreate instance.stringList = {} return instance end function ScriptWriter:makeFileForLoadedSettings() self:buildInstanceMetatable() self:buildInstanceCreationMethod() self:buildSettersAndGetters() self:buildReturn() self:writeStringsToFile() end --very first line of any script that will have instances function ScriptWriter:buildInstanceMetatable() table.insert(self.stringList, "local " .. self.name .. " = {}" .. newLine) table.insert(self.stringList, newLine) end --every script made this way needs a new method to create its instances function ScriptWriter:buildInstanceCreationMethod() --new() function declaration table.insert(self.stringList, ("function " .. self.name .. ":new(")) self:buildNewArguments() table.insert(self.stringList, ")" .. newLine) --first line inside :new() function table.insert(self.stringList, twoSpaceIndent .. "local instance = setmetatable({}, { __index = self })" .. newLine) --add designated arguments inside :new() self:buildNewArgumentVariables() --create the instance variables with the loaded values for key,value in pairs(self.instanceVariables) do table.insert(self.stringList, twoSpaceIndent .. "instance." .. key .. equalsWithSpaces .. value .. newLine) end --close the :new() function table.insert(self.stringList, twoSpaceIndent .. "return instance" .. newLine) table.insert(self.stringList, "end" .. newLine) table.insert(self.stringList, newLine) end function ScriptWriter:buildNewArguments() --if there are arguments for :new(), add them for key,value in ipairs(self.newArguments) do table.insert(self.stringList, value) table.insert(self.stringList, ", ") end if next(self.newArguments) ~= nil then --makes sure the table is not empty first table.remove(self.stringList) --remove the very last element, which will be the extra ", " end end function ScriptWriter:buildNewArgumentVariables() --add the designated arguments to :new() for key, value in ipairs(self.newArguments) do table.insert(self.stringList, twoSpaceIndent .. "instance." .. value .. equalsWithSpaces .. value .. newLine) end end --the instance variables need separate code because their names have to be the key and not the argument name function ScriptWriter:buildSettersAndGetters() for key,value in ipairs(self.newArguments) do self:buildArgumentSetter(value) self:buildArgumentGetter(value) table.insert(self.stringList, newLine) end for key,value in pairs(self.instanceVariables) do self:buildInstanceVariableSetter(key, value) self:buildInstanceVariableGetter(key, value) table.insert(self.stringList, newLine) end end --code for arguments passed in function ScriptWriter:buildArgumentSetter(variable) table.insert(self.stringList, "function " .. self.name .. ":set_" .. variable .. "(newValue)" .. newLine) table.insert(self.stringList, twoSpaceIndent .. "self." .. variable .. equalsWithSpaces .. "newValue" .. newLine) table.insert(self.stringList, "end" .. newLine) end function ScriptWriter:buildArgumentGetter(variable) table.insert(self.stringList, "function " .. self.name .. ":get_" .. variable .. "()" .. newLine) table.insert(self.stringList, twoSpaceIndent .. "return " .. "self." .. variable .. newLine) table.insert(self.stringList, "end" .. newLine) end --code for instance variable values passed in function ScriptWriter:buildInstanceVariableSetter(key, variable) table.insert(self.stringList, "function " .. self.name .. ":set_" .. key .. "(newValue)" .. newLine) table.insert(self.stringList, twoSpaceIndent .. "self." .. key .. equalsWithSpaces .. "newValue" .. newLine) table.insert(self.stringList, "end" .. newLine) end function ScriptWriter:buildInstanceVariableGetter(key, variable) table.insert(self.stringList, "function " .. self.name .. ":get_" .. key .. "()" .. newLine) table.insert(self.stringList, twoSpaceIndent .. "return " .. "self." .. key .. newLine) table.insert(self.stringList, "end" .. newLine) end --last line of any script that will have instances function ScriptWriter:buildReturn() table.insert(self.stringList, "return " .. self.name) end function ScriptWriter:writeStringsToFile() local fileName = (self.name .. ".lua") file = io.open(fileName, 'w') for key,value in ipairs(self.stringList) do file:write(value) end file:close() end return ScriptWriter And here is what the code provided will generate: local ScriptIAmMaking = {} function ScriptIAmMaking:new(argumentName) local instance = setmetatable({}, { __index = self }) instance.argumentName = argumentName instance.name = 'test' instance.one = 1 return instance end function ScriptIAmMaking:set_argumentName(newValue) self.argumentName = newValue end function ScriptIAmMaking:get_argumentName() return self.argumentName end function ScriptIAmMaking:set_name(newValue) self.name = newValue end function ScriptIAmMaking:get_name() return self.name end function ScriptIAmMaking:set_one(newValue) self.one = newValue end function ScriptIAmMaking:get_one() return self.one end return ScriptIAmMaking All of this is generated with these calls: local scripter = scriptWriter:new(scriptName, {"argumentName"}, {name = "'test'", one = 1}) scripter:makeFileForLoadedSettings() I am not sure if I am correct that this could be useful in certain situations. What I am looking for is feedback on the readability of the code, and following Lua best practices. I would also love to hear whether this approach is a valid one, and whether the way that I have done things will be extensible.

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• DotNetNuke create new portal didnt create new portal

  - by Jonesy

  hi folks, I've installed dotnetnuke today for the first time, I've created a new portal via host/portals. It says its created it but just doesn't find it. I just don't know how/why? The portal ID is 4. and there is a directory in dotnetnuke/Portals/4 But the url localhost/bmd (name of the portal) doesn't resolve to anything/ Anyone know a solution to this? maybe it happened to you too? Cheers

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• Camera for 2.5D Game

  - by me--

  I'm hoping someone can explain this to me like I'm 5, because I've been struggling with this for hours and simply cannot understand what I'm doing wrong. I've written a Camera class for my 2.5D game. The intention is to support world and screen spaces like this: The camera is the black thing on the right. The +Z axis is upwards in that image, with -Z heading downwards. As you can see, both world space and screen space have (0, 0) at their top-left. I started writing some unit tests to prove that my camera was working as expected, and that's where things started getting...strange. My tests plot coordinates in world, view, and screen spaces. Eventually I will use image comparison to assert that they are correct, but for now my test just displays the result. The render logic uses Camera.ViewMatrix to transform world space to view space, and Camera.WorldPointToScreen to transform world space to screen space. Here is an example test: [Fact] public void foo() { var camera = new Camera(new Viewport(0, 0, 250, 100)); DrawingVisual worldRender; DrawingVisual viewRender; DrawingVisual screenRender; this.Render(camera, out worldRender, out viewRender, out screenRender, new Vector3(30, 0, 0), new Vector3(30, 40, 0)); this.ShowRenders(camera, worldRender, viewRender, screenRender); } And here's what pops up when I run this test: World space looks OK, although I suspect the z axis is going into the screen instead of towards the viewer. View space has me completely baffled. I was expecting the camera to be sitting above (0, 0) and looking towards the center of the scene. Instead, the z axis seems to be the wrong way around, and the camera is positioned in the opposite corner to what I expect! I suspect screen space will be another thing altogether, but can anyone explain what I'm doing wrong in my Camera class? UPDATE I made some progress in terms of getting things to look visually as I expect, but only through intuition: not an actual understanding of what I'm doing. Any enlightenment would be greatly appreciated. I realized that my view space was flipped both vertically and horizontally compared to what I expected, so I changed my view matrix to scale accordingly: this.viewMatrix = Matrix.CreateLookAt(this.location, this.target, this.up) * Matrix.CreateScale(this.zoom, this.zoom, 1) * Matrix.CreateScale(-1, -1, 1); I could combine the two CreateScale calls, but have left them separate for clarity. Again, I have no idea why this is necessary, but it fixed my view space: But now my screen space needs to be flipped vertically, so I modified my projection matrix accordingly: this.projectionMatrix = Matrix.CreatePerspectiveFieldOfView(0.7853982f, viewport.AspectRatio, 1, 2) * Matrix.CreateScale(1, -1, 1); And this results in what I was expecting from my first attempt: I have also just tried using Camera to render sprites via a SpriteBatch to make sure everything works there too, and it does. But the question remains: why do I need to do all this flipping of axes to get the space coordinates the way I expect? UPDATE 2 I've since improved my rendering logic in my test suite so that it supports geometries and so that lines get lighter the further away they are from the camera. I wanted to do this to avoid optical illusions and to further prove to myself that I'm looking at what I think I am. Here is an example: In this case, I have 3 geometries: a cube, a sphere, and a polyline on the top face of the cube. Notice how the darkening and lightening of the lines correctly identifies those portions of the geometries closer to the camera. If I remove the negative scaling I had to put in, I see: So you can see I'm still in the same boat - I still need those vertical and horizontal flips in my matrices to get things to appear correctly. In the interests of giving people a repro to play with, here is the complete code needed to generate the above. If you want to run via the test harness, just install the xunit package: Camera.cs: using Microsoft.Xna.Framework; using Microsoft.Xna.Framework.Graphics; using System.Diagnostics; public sealed class Camera { private readonly Viewport viewport; private readonly Matrix projectionMatrix; private Matrix? viewMatrix; private Vector3 location; private Vector3 target; private Vector3 up; private float zoom; public Camera(Viewport viewport) { this.viewport = viewport; // for an explanation of the negative scaling, see: http://gamedev.stackexchange.com/questions/63409/ this.projectionMatrix = Matrix.CreatePerspectiveFieldOfView(0.7853982f, viewport.AspectRatio, 1, 2) * Matrix.CreateScale(1, -1, 1); // defaults this.location = new Vector3(this.viewport.Width / 2, this.viewport.Height, 100); this.target = new Vector3(this.viewport.Width / 2, this.viewport.Height / 2, 0); this.up = new Vector3(0, 0, 1); this.zoom = 1; } public Viewport Viewport { get { return this.viewport; } } public Vector3 Location { get { return this.location; } set { this.location = value; this.viewMatrix = null; } } public Vector3 Target { get { return this.target; } set { this.target = value; this.viewMatrix = null; } } public Vector3 Up { get { return this.up; } set { this.up = value; this.viewMatrix = null; } } public float Zoom { get { return this.zoom; } set { this.zoom = value; this.viewMatrix = null; } } public Matrix ProjectionMatrix { get { return this.projectionMatrix; } } public Matrix ViewMatrix { get { if (this.viewMatrix == null) { // for an explanation of the negative scaling, see: http://gamedev.stackexchange.com/questions/63409/ this.viewMatrix = Matrix.CreateLookAt(this.location, this.target, this.up) * Matrix.CreateScale(this.zoom) * Matrix.CreateScale(-1, -1, 1); } return this.viewMatrix.Value; } } public Vector2 WorldPointToScreen(Vector3 point) { var result = viewport.Project(point, this.ProjectionMatrix, this.ViewMatrix, Matrix.Identity); return new Vector2(result.X, result.Y); } public void WorldPointsToScreen(Vector3[] points, Vector2[] destination) { Debug.Assert(points != null); Debug.Assert(destination != null); Debug.Assert(points.Length == destination.Length); for (var i = 0; i < points.Length; ++i) { destination[i] = this.WorldPointToScreen(points[i]); } } } CameraFixture.cs: using Microsoft.Xna.Framework.Graphics; using System; using System.Collections.Generic; using System.Linq; using System.Windows; using System.Windows.Controls; using System.Windows.Media; using Xunit; using XNA = Microsoft.Xna.Framework; public sealed class CameraFixture { [Fact] public void foo() { var camera = new Camera(new Viewport(0, 0, 250, 100)); DrawingVisual worldRender; DrawingVisual viewRender; DrawingVisual screenRender; this.Render( camera, out worldRender, out viewRender, out screenRender, new Sphere(30, 15) { WorldMatrix = XNA.Matrix.CreateTranslation(155, 50, 0) }, new Cube(30) { WorldMatrix = XNA.Matrix.CreateTranslation(75, 60, 15) }, new PolyLine(new XNA.Vector3(0, 0, 0), new XNA.Vector3(10, 10, 0), new XNA.Vector3(20, 0, 0), new XNA.Vector3(0, 0, 0)) { WorldMatrix = XNA.Matrix.CreateTranslation(65, 55, 30) }); this.ShowRenders(worldRender, viewRender, screenRender); } #region Supporting Fields private static readonly Pen xAxisPen = new Pen(Brushes.Red, 2); private static readonly Pen yAxisPen = new Pen(Brushes.Green, 2); private static readonly Pen zAxisPen = new Pen(Brushes.Blue, 2); private static readonly Pen viewportPen = new Pen(Brushes.Gray, 1); private static readonly Pen nonScreenSpacePen = new Pen(Brushes.Black, 0.5); private static readonly Color geometryBaseColor = Colors.Black; #endregion #region Supporting Methods private void Render(Camera camera, out DrawingVisual worldRender, out DrawingVisual viewRender, out DrawingVisual screenRender, params Geometry[] geometries) { var worldDrawingVisual = new DrawingVisual(); var viewDrawingVisual = new DrawingVisual(); var screenDrawingVisual = new DrawingVisual(); const int axisLength = 15; using (var worldDrawingContext = worldDrawingVisual.RenderOpen()) using (var viewDrawingContext = viewDrawingVisual.RenderOpen()) using (var screenDrawingContext = screenDrawingVisual.RenderOpen()) { // draw lines around the camera's viewport var viewportBounds = camera.Viewport.Bounds; var viewportLines = new Tuple<int, int, int, int>[] { Tuple.Create(viewportBounds.Left, viewportBounds.Bottom, viewportBounds.Left, viewportBounds.Top), Tuple.Create(viewportBounds.Left, viewportBounds.Top, viewportBounds.Right, viewportBounds.Top), Tuple.Create(viewportBounds.Right, viewportBounds.Top, viewportBounds.Right, viewportBounds.Bottom), Tuple.Create(viewportBounds.Right, viewportBounds.Bottom, viewportBounds.Left, viewportBounds.Bottom) }; foreach (var viewportLine in viewportLines) { var viewStart = XNA.Vector3.Transform(new XNA.Vector3(viewportLine.Item1, viewportLine.Item2, 0), camera.ViewMatrix); var viewEnd = XNA.Vector3.Transform(new XNA.Vector3(viewportLine.Item3, viewportLine.Item4, 0), camera.ViewMatrix); var screenStart = camera.WorldPointToScreen(new XNA.Vector3(viewportLine.Item1, viewportLine.Item2, 0)); var screenEnd = camera.WorldPointToScreen(new XNA.Vector3(viewportLine.Item3, viewportLine.Item4, 0)); worldDrawingContext.DrawLine(viewportPen, new Point(viewportLine.Item1, viewportLine.Item2), new Point(viewportLine.Item3, viewportLine.Item4)); viewDrawingContext.DrawLine(viewportPen, new Point(viewStart.X, viewStart.Y), new Point(viewEnd.X, viewEnd.Y)); screenDrawingContext.DrawLine(viewportPen, new Point(screenStart.X, screenStart.Y), new Point(screenEnd.X, screenEnd.Y)); } // draw axes var axisLines = new Tuple<int, int, int, int, int, int, Pen>[] { Tuple.Create(0, 0, 0, axisLength, 0, 0, xAxisPen), Tuple.Create(0, 0, 0, 0, axisLength, 0, yAxisPen), Tuple.Create(0, 0, 0, 0, 0, axisLength, zAxisPen) }; foreach (var axisLine in axisLines) { var viewStart = XNA.Vector3.Transform(new XNA.Vector3(axisLine.Item1, axisLine.Item2, axisLine.Item3), camera.ViewMatrix); var viewEnd = XNA.Vector3.Transform(new XNA.Vector3(axisLine.Item4, axisLine.Item5, axisLine.Item6), camera.ViewMatrix); var screenStart = camera.WorldPointToScreen(new XNA.Vector3(axisLine.Item1, axisLine.Item2, axisLine.Item3)); var screenEnd = camera.WorldPointToScreen(new XNA.Vector3(axisLine.Item4, axisLine.Item5, axisLine.Item6)); worldDrawingContext.DrawLine(axisLine.Item7, new Point(axisLine.Item1, axisLine.Item2), new Point(axisLine.Item4, axisLine.Item5)); viewDrawingContext.DrawLine(axisLine.Item7, new Point(viewStart.X, viewStart.Y), new Point(viewEnd.X, viewEnd.Y)); screenDrawingContext.DrawLine(axisLine.Item7, new Point(screenStart.X, screenStart.Y), new Point(screenEnd.X, screenEnd.Y)); } // for all points in all geometries to be rendered, find the closest and furthest away from the camera so we can lighten lines that are further away var distancesToAllGeometrySections = from geometry in geometries let geometryViewMatrix = geometry.WorldMatrix * camera.ViewMatrix from section in geometry.Sections from point in new XNA.Vector3[] { section.Item1, section.Item2 } let viewPoint = XNA.Vector3.Transform(point, geometryViewMatrix) select viewPoint.Length(); var furthestDistance = distancesToAllGeometrySections.Max(); var closestDistance = distancesToAllGeometrySections.Min(); var deltaDistance = Math.Max(0.000001f, furthestDistance - closestDistance); // draw each geometry for (var i = 0; i < geometries.Length; ++i) { var geometry = geometries[i]; // there's probably a more correct name for this, but basically this gets the geometry relative to the camera so we can check how far away each point is from the camera var geometryViewMatrix = geometry.WorldMatrix * camera.ViewMatrix; // we order roughly by those sections furthest from the camera to those closest, so that the closer ones "overwrite" the ones further away var orderedSections = from section in geometry.Sections let startPointRelativeToCamera = XNA.Vector3.Transform(section.Item1, geometryViewMatrix) let endPointRelativeToCamera = XNA.Vector3.Transform(section.Item2, geometryViewMatrix) let startPointDistance = startPointRelativeToCamera.Length() let endPointDistance = endPointRelativeToCamera.Length() orderby (startPointDistance + endPointDistance) descending select new { Section = section, DistanceToStart = startPointDistance, DistanceToEnd = endPointDistance }; foreach (var orderedSection in orderedSections) { var start = XNA.Vector3.Transform(orderedSection.Section.Item1, geometry.WorldMatrix); var end = XNA.Vector3.Transform(orderedSection.Section.Item2, geometry.WorldMatrix); var viewStart = XNA.Vector3.Transform(start, camera.ViewMatrix); var viewEnd = XNA.Vector3.Transform(end, camera.ViewMatrix); worldDrawingContext.DrawLine(nonScreenSpacePen, new Point(start.X, start.Y), new Point(end.X, end.Y)); viewDrawingContext.DrawLine(nonScreenSpacePen, new Point(viewStart.X, viewStart.Y), new Point(viewEnd.X, viewEnd.Y)); // screen rendering is more complicated purely because I wanted geometry to fade the further away it is from the camera // otherwise, it's very hard to tell whether the rendering is actually correct or not var startDistanceRatio = (orderedSection.DistanceToStart - closestDistance) / deltaDistance; var endDistanceRatio = (orderedSection.DistanceToEnd - closestDistance) / deltaDistance; // lerp towards white based on distance from camera, but only to a maximum of 90% var startColor = Lerp(geometryBaseColor, Colors.White, startDistanceRatio * 0.9f); var endColor = Lerp(geometryBaseColor, Colors.White, endDistanceRatio * 0.9f); var screenStart = camera.WorldPointToScreen(start); var screenEnd = camera.WorldPointToScreen(end); var brush = new LinearGradientBrush { StartPoint = new Point(screenStart.X, screenStart.Y), EndPoint = new Point(screenEnd.X, screenEnd.Y), MappingMode = BrushMappingMode.Absolute }; brush.GradientStops.Add(new GradientStop(startColor, 0)); brush.GradientStops.Add(new GradientStop(endColor, 1)); var pen = new Pen(brush, 1); brush.Freeze(); pen.Freeze(); screenDrawingContext.DrawLine(pen, new Point(screenStart.X, screenStart.Y), new Point(screenEnd.X, screenEnd.Y)); } } } worldRender = worldDrawingVisual; viewRender = viewDrawingVisual; screenRender = screenDrawingVisual; } private static float Lerp(float start, float end, float amount) { var difference = end - start; var adjusted = difference * amount; return start + adjusted; } private static Color Lerp(Color color, Color to, float amount) { var sr = color.R; var sg = color.G; var sb = color.B; var er = to.R; var eg = to.G; var eb = to.B; var r = (byte)Lerp(sr, er, amount); var g = (byte)Lerp(sg, eg, amount); var b = (byte)Lerp(sb, eb, amount); return Color.FromArgb(255, r, g, b); } private void ShowRenders(DrawingVisual worldRender, DrawingVisual viewRender, DrawingVisual screenRender) { var itemsControl = new ItemsControl(); itemsControl.Items.Add(new HeaderedContentControl { Header = "World", Content = new DrawingVisualHost(worldRender)}); itemsControl.Items.Add(new HeaderedContentControl { Header = "View", Content = new DrawingVisualHost(viewRender) }); itemsControl.Items.Add(new HeaderedContentControl { Header = "Screen", Content = new DrawingVisualHost(screenRender) }); var window = new Window { Title = "Renders", Content = itemsControl, ShowInTaskbar = true, SizeToContent = SizeToContent.WidthAndHeight }; window.ShowDialog(); } #endregion #region Supporting Types // stupidly simple 3D geometry class, consisting of a series of sections that will be connected by lines private abstract class Geometry { public abstract IEnumerable<Tuple<XNA.Vector3, XNA.Vector3>> Sections { get; } public XNA.Matrix WorldMatrix { get; set; } } private sealed class Line : Geometry { private readonly XNA.Vector3 magnitude; public Line(XNA.Vector3 magnitude) { this.magnitude = magnitude; } public override IEnumerable<Tuple<XNA.Vector3, XNA.Vector3>> Sections { get { yield return Tuple.Create(XNA.Vector3.Zero, this.magnitude); } } } private sealed class PolyLine : Geometry { private readonly XNA.Vector3[] points; public PolyLine(params XNA.Vector3[] points) { this.points = points; } public override IEnumerable<Tuple<XNA.Vector3, XNA.Vector3>> Sections { get { if (this.points.Length < 2) { yield break; } var end = this.points[0]; for (var i = 1; i < this.points.Length; ++i) { var start = end; end = this.points[i]; yield return Tuple.Create(start, end); } } } } private sealed class Cube : Geometry { private readonly float size; public Cube(float size) { this.size = size; } public override IEnumerable<Tuple<XNA.Vector3, XNA.Vector3>> Sections { get { var halfSize = this.size / 2; var frontBottomLeft = new XNA.Vector3(-halfSize, halfSize, -halfSize); var frontBottomRight = new XNA.Vector3(halfSize, halfSize, -halfSize); var frontTopLeft = new XNA.Vector3(-halfSize, halfSize, halfSize); var frontTopRight = new XNA.Vector3(halfSize, halfSize, halfSize); var backBottomLeft = new XNA.Vector3(-halfSize, -halfSize, -halfSize); var backBottomRight = new XNA.Vector3(halfSize, -halfSize, -halfSize); var backTopLeft = new XNA.Vector3(-halfSize, -halfSize, halfSize); var backTopRight = new XNA.Vector3(halfSize, -halfSize, halfSize); // front face yield return Tuple.Create(frontBottomLeft, frontBottomRight); yield return Tuple.Create(frontBottomLeft, frontTopLeft); yield return Tuple.Create(frontTopLeft, frontTopRight); yield return Tuple.Create(frontTopRight, frontBottomRight); // left face yield return Tuple.Create(frontTopLeft, backTopLeft); yield return Tuple.Create(backTopLeft, backBottomLeft); yield return Tuple.Create(backBottomLeft, frontBottomLeft); // right face yield return Tuple.Create(frontTopRight, backTopRight); yield return Tuple.Create(backTopRight, backBottomRight); yield return Tuple.Create(backBottomRight, frontBottomRight); // back face yield return Tuple.Create(backBottomLeft, backBottomRight); yield return Tuple.Create(backTopLeft, backTopRight); } } } private sealed class Sphere : Geometry { private readonly float radius; private readonly int subsections; public Sphere(float radius, int subsections) { this.radius = radius; this.subsections = subsections; } public override IEnumerable<Tuple<XNA.Vector3, XNA.Vector3>> Sections { get { var latitudeLines = this.subsections; var longitudeLines = this.subsections; // see http://stackoverflow.com/a/4082020/5380 var results = from latitudeLine in Enumerable.Range(0, latitudeLines) from longitudeLine in Enumerable.Range(0, longitudeLines) let latitudeRatio = latitudeLine / (float)latitudeLines let longitudeRatio = longitudeLine / (float)longitudeLines let nextLatitudeRatio = (latitudeLine + 1) / (float)latitudeLines let nextLongitudeRatio = (longitudeLine + 1) / (float)longitudeLines let z1 = Math.Cos(Math.PI * latitudeRatio) let z2 = Math.Cos(Math.PI * nextLatitudeRatio) let x1 = Math.Sin(Math.PI * latitudeRatio) * Math.Cos(Math.PI * 2 * longitudeRatio) let y1 = Math.Sin(Math.PI * latitudeRatio) * Math.Sin(Math.PI * 2 * longitudeRatio) let x2 = Math.Sin(Math.PI * nextLatitudeRatio) * Math.Cos(Math.PI * 2 * longitudeRatio) let y2 = Math.Sin(Math.PI * nextLatitudeRatio) * Math.Sin(Math.PI * 2 * longitudeRatio) let x3 = Math.Sin(Math.PI * latitudeRatio) * Math.Cos(Math.PI * 2 * nextLongitudeRatio) let y3 = Math.Sin(Math.PI * latitudeRatio) * Math.Sin(Math.PI * 2 * nextLongitudeRatio) let start = new XNA.Vector3((float)x1 * radius, (float)y1 * radius, (float)z1 * radius) let firstEnd = new XNA.Vector3((float)x2 * radius, (float)y2 * radius, (float)z2 * radius) let secondEnd = new XNA.Vector3((float)x3 * radius, (float)y3 * radius, (float)z1 * radius) select new { First = Tuple.Create(start, firstEnd), Second = Tuple.Create(start, secondEnd) }; foreach (var result in results) { yield return result.First; yield return result.Second; } } } } #endregion }

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• Twitter User/Search Feature Header Support in LINQ to Twitter

  - by Joe Mayo

  LINQ to Twitter’s goal is to support the entire Twitter API. So, if you see a new feature pop-up, it will be in-queue for inclusion. The same holds for the new X-Feature… response headers for User/Search requests.  However, you don’t have to wait for a special property on the TwitterContext to access these headers, you can just use them via the TwitterContext.ResponseHeaders collection. The following code demonstrates how to access the new X-Feature… headers with LINQ to Twitter: var user = (from usr in twitterCtx.User where usr.Type == UserType.Search && usr.Query == "Joe Mayo" select usr) .FirstOrDefault(); Console.WriteLine( "X-FeatureRateLimit-Limit: {0}\n" + "X-FeatureRateLimit-Remaining: {1}\n" + "X-FeatureRateLimit-Reset: {2}\n" + "X-FeatureRateLimit-Class: {3}\n", twitterCtx.ResponseHeaders["X-FeatureRateLimit-Limit"], twitterCtx.ResponseHeaders["X-FeatureRateLimit-Remaining"], twitterCtx.ResponseHeaders["X-FeatureRateLimit-Reset"], twitterCtx.ResponseHeaders["X-FeatureRateLimit-Class"]); The query above is from the User entity, whose type is Search; allowing you to search for the Twitter user whose name is specified by the Query parameter filter. After materializing the query, with FirstOrDefault, twitterCtx will hold all of the headers, including X-Feature… that Twitter returned.  Running the code above will display results similar to the following: X-FeatureRateLimit-Limit: 60 X-FeatureRateLimit-Remaining: 59 X-FeatureRateLimit-Reset: 1271452177 X-FeatureRateLimit-Class: namesearch In addition to getting the X-Feature… headers a capability you might have noticed is that the TwitterContext.ResponseHeaders collection will contain any HTTP that Twitter sends back to a query. Therefore, you’ll be able to access new Twitter headers anytime in the future with LINQ to Twitter. @JoeMayo

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• Windows Azure: Import/Export Hard Drives, VM ACLs, Web Sockets, Remote Debugging, Continuous Delivery, New Relic, Billing Alerts and More

  - by ScottGu

  Two weeks ago we released a giant set of improvements to Windows Azure, as well as a significant update of the Windows Azure SDK. This morning we released another massive set of enhancements to Windows Azure.  Today’s new capabilities include: Storage: Import/Export Hard Disk Drives to your Storage Accounts HDInsight: General Availability of our Hadoop Service in the cloud Virtual Machines: New VM Gallery, ACL support for VIPs Web Sites: WebSocket and Remote Debugging Support Notification Hubs: Segmented customer push notification support with tag expressions TFS & GIT: Continuous Delivery Support for Web Sites + Cloud Services Developer Analytics: New Relic support for Web Sites + Mobile Services Service Bus: Support for partitioned queues and topics Billing: New Billing Alert Service that sends emails notifications when your bill hits a threshold you define All of these improvements are now available to use immediately (note that some features are still in preview).  Below are more details about them. Storage: Import/Export Hard Disk Drives to Windows Azure I am excited to announce the preview of our new Windows Azure Import/Export Service! The Windows Azure Import/Export Service enables you to move large amounts of on-premises data into and out of your Windows Azure Storage accounts. It does this by enabling you to securely ship hard disk drives directly to our Windows Azure data centers. Once we receive the drives we’ll automatically transfer the data to or from your Windows Azure Storage account.  This enables you to import or export massive amounts of data more quickly and cost effectively (and not be constrained by available network bandwidth). Encrypted Transport Our Import/Export service provides built-in support for BitLocker disk encryption – which enables you to securely encrypt data on the hard drives before you send it, and not have to worry about it being compromised even if the disk is lost/stolen in transit (since the content on the transported hard drives is completely encrypted and you are the only one who has the key to it).  The drive preparation tool we are shipping today makes setting up bitlocker encryption on these hard drives easy. How to Import/Export your first Hard Drive of Data You can read our Getting Started Guide to learn more about how to begin using the import/export service.  You can create import and export jobs via the Windows Azure Management Portal as well as programmatically using our Server Management APIs. It is really easy to create a new import or export job using the Windows Azure Management Portal.  Simply navigate to a Windows Azure storage account, and then click the new Import/Export tab now available within it (note: if you don’t have this tab make sure to sign-up for the Import/Export preview): Then click the “Create Import Job” or “Create Export Job” commands at the bottom of it.  This will launch a wizard that easily walks you through the steps required: For more comprehensive information about Import/Export, refer to Windows Azure Storage team blog.  You can also send questions and comments to the [email protected] email address. We think you’ll find this new service makes it much easier to move data into and out of Windows Azure, and it will dramatically cut down the network bandwidth required when working on large data migration projects.  We hope you like it. HDInsight: 100% Compatible Hadoop Service in the Cloud Last week we announced the general availability release of Windows Azure HDInsight. HDInsight is a 100% compatible Hadoop service that allows you to easily provision and manage Hadoop clusters for big data processing in Windows Azure.  This release is now live in production, backed by an enterprise SLA, supported 24x7 by Microsoft Support, and is ready to use for production scenarios. HDInsight allows you to use Apache Hadoop tools, such as Pig and Hive, to process large amounts of data in Windows Azure Blob Storage. Because data is stored in Windows Azure Blob Storage, you can choose to dynamically create Hadoop clusters only when you need them, and then shut them down when they are no longer required (since you pay only for the time the Hadoop cluster instances are running this provides a super cost effective way to use them).  You can create Hadoop clusters using either the Windows Azure Management Portal (see below) or using our PowerShell and Cross Platform Command line tools: The import/export hard drive support that came out today is a perfect companion service to use with HDInsight – the combination allows you to easily ingest, process and optionally export a limitless amount of data.  We’ve also integrated HDInsight with our Business Intelligence tools, so users can leverage familiar tools like Excel in order to analyze the output of jobs.  You can find out more about how to get started with HDInsight here. Virtual Machines: VM Gallery Enhancements Today’s update of Windows Azure brings with it a new Virtual Machine gallery that you can use to create new VMs in the cloud.  You can launch the gallery by doing New->Compute->Virtual Machine->From Gallery within the Windows Azure Management Portal: The new Virtual Machine Gallery includes some nice enhancements that make it even easier to use: Search: You can now easily search and filter images using the search box in the top-right of the dialog.  For example, simply type “SQL” and we’ll filter to show those images in the gallery that contain that substring. Category Tree-view: Each month we add more built-in VM images to the gallery.  You can continue to browse these using the “All” view within the VM Gallery – or now quickly filter them using the category tree-view on the left-hand side of the dialog.  For example, by selecting “Oracle” in the tree-view you can now quickly filter to see the official Oracle supplied images. MSDN and Supported checkboxes: With today’s update we are also introducing filters that makes it easy to filter out types of images that you may not be interested in. The first checkbox is MSDN: using this filter you can exclude any image that is not part of the Windows Azure benefits for MSDN subscribers (which have highly discounted pricing - you can learn more about the MSDN pricing here). The second checkbox is Supported: this filter will exclude any image that contains prerelease software, so you can feel confident that the software you choose to deploy is fully supported by Windows Azure and our partners. Sort options: We sort gallery images by what we think customers are most interested in, but sometimes you might want to sort using different views. So we’re providing some additional sort options, like “Newest,” to customize the image list for what suits you best. Pricing information: We now provide additional pricing information about images and options on how to cost effectively run them directly within the VM Gallery. The above improvements make it even easier to use the VM Gallery and quickly create launch and run Virtual Machines in the cloud. Virtual Machines: ACL Support for VIPs A few months ago we exposed the ability to configure Access Control Lists (ACLs) for Virtual Machines using Windows PowerShell cmdlets and our Service Management API. With today’s release, you can now configure VM ACLs using the Windows Azure Management Portal as well. You can now do this by clicking the new Manage ACL command in the Endpoints tab of a virtual machine instance: This will enable you to configure an ordered list of permit and deny rules to scope the traffic that can access your VM’s network endpoints. For example, if you were on a virtual network, you could limit RDP access to a Windows Azure virtual machine to only a few computers attached to your enterprise. Or if you weren’t on a virtual network you could alternatively limit traffic from public IPs that can access your workloads: Here is the default behaviors for ACLs in Windows Azure: By default (i.e. no rules specified), all traffic is permitted. When using only Permit rules, all other traffic is denied. When using only Deny rules, all other traffic is permitted. When there is a combination of Permit and Deny rules, all other traffic is denied. Lastly, remember that configuring endpoints does not automatically configure them within the VM if it also has firewall rules enabled at the OS level.  So if you create an endpoint using the Windows Azure Management Portal, Windows PowerShell, or REST API, be sure to also configure your guest VM firewall appropriately as well. Web Sites: Web Sockets Support With today’s release you can now use Web Sockets with Windows Azure Web Sites.  This feature enables you to easily integrate real-time communication scenarios within your web based applications, and is available at no extra charge (it even works with the free tier).  Higher level programming libraries like SignalR and socket.io are also now supported with it. You can enable Web Sockets support on a web site by navigating to the Configure tab of a Web Site, and by toggling Web Sockets support to “on”: Once Web Sockets is enabled you can start to integrate some really cool scenarios into your web applications.  Check out the new SignalR documentation hub on www.asp.net to learn more about some of the awesome scenarios you can do with it. Web Sites: Remote Debugging Support The Windows Azure SDK 2.2 we released two weeks ago introduced remote debugging support for Windows Azure Cloud Services. With today’s Windows Azure release we are extending this remote debugging support to also work with Windows Azure Web Sites. With live, remote debugging support inside of Visual Studio, you are able to have more visibility than ever before into how your code is operating live in Windows Azure. It is now super easy to attach the debugger and quickly see what is going on with your application in the cloud. Remote Debugging of a Windows Azure Web Site using VS 2013 Enabling the remote debugging of a Windows Azure Web Site using VS 2013 is really easy.  Start by opening up your web application’s project within Visual Studio. Then navigate to the “Server Explorer” tab within Visual Studio, and click on the deployed web-site you want to debug that is running within Windows Azure using the Windows Azure->Web Sites node in the Server Explorer.  Then right-click and choose the “Attach Debugger” option on it: When you do this Visual Studio will remotely attach the debugger to the Web Site running within Windows Azure.  The debugger will then stop the web site’s execution when it hits any break points that you have set within your web application’s project inside Visual Studio.  For example, below I set a breakpoint on the “ViewBag.Message” assignment statement within the HomeController of the standard ASP.NET MVC project template.  When I hit refresh on the “About” page of the web site within the browser, the breakpoint was triggered and I am now able to debug the app remotely using Visual Studio: Note above how we can debug variables (including autos/watchlist/etc), as well as use the Immediate and Command Windows. In the debug session above I used the Immediate Window to explore some of the request object state, as well as to dynamically change the ViewBag.Message property.  When we click the the “Continue” button (or press F5) the app will continue execution and the Web Site will render the content back to the browser.  This makes it super easy to debug web apps remotely. Tips for Better Debugging To get the best experience while debugging, we recommend publishing your site using the Debug configuration within Visual Studio’s Web Publish dialog. This will ensure that debug symbol information is uploaded to the Web Site which will enable a richer debug experience within Visual Studio.  You can find this option on the Web Publish dialog on the Settings tab: When you ultimately deploy/run the application in production we recommend using the “Release” configuration setting – the release configuration is memory optimized and will provide the best production performance.  To learn more about diagnosing and debugging Windows Azure Web Sites read our new Troubleshooting Windows Azure Web Sites in Visual Studio guide. Notification Hubs: Segmented Push Notification support with tag expressions In August we announced the General Availability of Windows Azure Notification Hubs - a powerful Mobile Push Notifications service that makes it easy to send high volume push notifications with low latency from any mobile app back-end.  Notification hubs can be used with any mobile app back-end (including ones built using our Mobile Services capability) and can also be used with back-ends that run in the cloud as well as on-premises. Beginning with the initial release, Notification Hubs allowed developers to send personalized push notifications to both individual users as well as groups of users by interest, by associating their devices with tags representing the logical target of the notification. For example, by registering all devices of customers interested in a favorite MLB team with a corresponding tag, it is possible to broadcast one message to millions of Boston Red Sox fans and another message to millions of St. Louis Cardinals fans with a single API call respectively. New support for using tag expressions to enable advanced customer segmentation With today’s release we are adding support for even more advanced customer targeting.  You can now identify customers that you want to send push notifications to by defining rich tag expressions. With tag expressions, you can now not only broadcast notifications to Boston Red Sox fans, but take that segmenting a step farther and reach more granular segments. This opens up a variety of scenarios, for example: Offers based on multiple preferences—e.g. send a game day vegetarian special to users tagged as both a Boston Red Sox fan AND a vegetarian Push content to multiple segments in a single message—e.g. rain delay information only to users who are tagged as either a Boston Red Sox fan OR a St. Louis Cardinal fan Avoid presenting subsets of a segment with irrelevant content—e.g. season ticket availability reminder to users who are tagged as a Boston Red Sox fan but NOT also a season ticket holder To illustrate with code, consider a restaurant chain app that sends an offer related to a Red Sox vs Cardinals game for users in Boston. Devices can be tagged by your app with location tags (e.g. “Loc:Boston”) and interest tags (e.g. “Follows:RedSox”, “Follows:Cardinals”), and then a notification can be sent by your back-end to “(Follows:RedSox || Follows:Cardinals) && Loc:Boston” in order to deliver an offer to all devices in Boston that follow either the RedSox or the Cardinals. This can be done directly in your server backend send logic using the code below: var notification = new WindowsNotification(messagePayload); hub.SendNotificationAsync(notification, "(Follows:RedSox || Follows:Cardinals) && Loc:Boston"); In your expressions you can use all Boolean operators: AND (&&), OR (||), and NOT (!).  Some other cool use cases for tag expressions that are now supported include: Social: To “all my group except me” - group:id && !user:id Events: Touchdown event is sent to everybody following either team or any of the players involved in the action: Followteam:A || Followteam:B || followplayer:1 || followplayer:2 … Hours: Send notifications at specific times. E.g. Tag devices with time zone and when it is 12pm in Seattle send to: GMT8 && follows:thaifood Versions and platforms: Send a reminder to people still using your first version for Android - version:1.0 && platform:Android For help on getting started with Notification Hubs, visit the Notification Hub documentation center.  Then download the latest NuGet package (or use the Notification Hubs REST APIs directly) to start sending push notifications using tag expressions.  They are really powerful and enable a bunch of great new scenarios. TFS & GIT: Continuous Delivery Support for Web Sites + Cloud Services With today’s Windows Azure release we are making it really easy to enable continuous delivery support with Windows Azure and Team Foundation Services.  Team Foundation Services is a cloud based offering from Microsoft that provides integrated source control (with both TFS and Git support), build server, test execution, collaboration tools, and agile planning support.  It makes it really easy to setup a team project (complete with automated builds and test runners) in the cloud, and it has really rich integration with Visual Studio. With today’s Windows Azure release it is now really easy to enable continuous delivery support with both TFS and Git based repositories hosted using Team Foundation Services.  This enables a workflow where when code is checked in, built successfully on an automated build server, and all tests pass on it – I can automatically have the app deployed on Windows Azure with zero manual intervention or work required. The below screen-shots demonstrate how to quickly setup a continuous delivery workflow to Windows Azure with a Git-based ASP.NET MVC project hosted using Team Foundation Services. Enabling Continuous Delivery to Windows Azure with Team Foundation Services The project I’m going to enable continuous delivery with is a simple ASP.NET MVC project whose source code I’m hosting using Team Foundation Services.  I did this by creating a “SimpleContinuousDeploymentTest” repository there using Git – and then used the new built-in Git tooling support within Visual Studio 2013 to push the source code to it.  Below is a screen-shot of the Git repository hosted within Team Foundation Services: I can access the repository within Visual Studio 2013 and easily make commits with it (as well as branch, merge and do other tasks).  Using VS 2013 I can also setup automated builds to take place in the cloud using Team Foundation Services every time someone checks in code to the repository: The cool thing about this is that I don’t have to buy or rent my own build server – Team Foundation Services automatically maintains its own build server farm and can automatically queue up a build for me (for free) every time someone checks in code using the above settings.  This build server (and automated testing) support now works with both TFS and Git based source control repositories. Connecting a Team Foundation Services project to Windows Azure Once I have a source repository hosted in Team Foundation Services with Automated Builds and Testing set up, I can then go even further and set it up so that it will be automatically deployed to Windows Azure when a source code commit is made to the repository (assuming the Build + Tests pass).  Enabling this is now really easy.  To set this up with a Windows Azure Web Site simply use the New->Compute->Web Site->Custom Create command inside the Windows Azure Management Portal.  This will create a dialog like below.  I gave the web site a name and then made sure the “Publish from source control” checkbox was selected: When we click next we’ll be prompted for the location of the source repository.  We’ll select “Team Foundation Services”: Once we do this we’ll be prompted for our Team Foundation Services account that our source repository is hosted under (in this case my TFS account is “scottguthrie”): When we click the “Authorize Now” button we’ll be prompted to give Windows Azure permissions to connect to the Team Foundation Services account.  Once we do this we’ll be prompted to pick the source repository we want to connect to.  Starting with today’s Windows Azure release you can now connect to both TFS and Git based source repositories.  This new support allows me to connect to the “SimpleContinuousDeploymentTest” respository we created earlier: Clicking the finish button will then create the Web Site with the continuous delivery hooks setup with Team Foundation Services.  Now every time someone pushes source control to the repository in Team Foundation Services, it will kick off an automated build, run all of the unit tests in the solution , and if they pass the app will be automatically deployed to our Web Site in Windows Azure.  You can monitor the history and status of these automated deployments using the Deployments tab within the Web Site: This enables a really slick continuous delivery workflow, and enables you to build and deploy apps in a really nice way. Developer Analytics: New Relic support for Web Sites + Mobile Services With today’s Windows Azure release we are making it really easy to enable Developer Analytics and Monitoring support with both Windows Azure Web Site and Windows Azure Mobile Services.  We are partnering with New Relic, who provide a great dev analytics and app performance monitoring offering, to enable this - and we have updated the Windows Azure Management Portal to make it really easy to configure. Enabling New Relic with a Windows Azure Web Site Enabling New Relic support with a Windows Azure Web Site is now really easy.  Simply navigate to the Configure tab of a Web Site and scroll down to the “developer analytics” section that is now within it: Clicking the “add-on” button will display some additional UI.  If you don’t already have a New Relic subscription, you can click the “view windows azure store” button to obtain a subscription (note: New Relic has a perpetually free tier so you can enable it even without paying anything): Clicking the “view windows azure store” button will launch the integrated Windows Azure Store experience we have within the Windows Azure Management Portal.  You can use this to browse from a variety of great add-on services – including New Relic: Select “New Relic” within the dialog above, then click the next button, and you’ll be able to choose which type of New Relic subscription you wish to purchase.  For this demo we’ll simply select the “Free Standard Version” – which does not cost anything and can be used forever:  Once we’ve signed-up for our New Relic subscription and added it to our Windows Azure account, we can go back to the Web Site’s configuration tab and choose to use the New Relic add-on with our Windows Azure Web Site.  We can do this by simply selecting it from the “add-on” dropdown (it is automatically populated within it once we have a New Relic subscription in our account): Clicking the “Save” button will then cause the Windows Azure Management Portal to automatically populate all of the needed New Relic configuration settings to our Web Site: Deploying the New Relic Agent as part of a Web Site The final step to enable developer analytics using New Relic is to add the New Relic runtime agent to our web app.  We can do this within Visual Studio by right-clicking on our web project and selecting the “Manage NuGet Packages” context menu: This will bring up the NuGet package manager.  You can search for “New Relic” within it to find the New Relic agent.  Note that there is both a 32-bit and 64-bit edition of it – make sure to install the version that matches how your Web Site is running within Windows Azure (note: you can configure your Web Site to run in either 32-bit or 64-bit mode using the Web Site’s “Configuration” tab within the Windows Azure Management Portal): Once we install the NuGet package we are all set to go.  We’ll simply re-publish the web site again to Windows Azure and New Relic will now automatically start monitoring the application Monitoring a Web Site using New Relic Now that the application has developer analytics support with New Relic enabled, we can launch the New Relic monitoring portal to start monitoring the health of it.  We can do this by clicking on the “Add Ons” tab in the left-hand side of the Windows Azure Management Portal.  Then select the New Relic add-on we signed-up for within it.  The Windows Azure Management Portal will provide some default information about the add-on when we do this.  Clicking the “Manage” button in the tray at the bottom will launch a new browser tab and single-sign us into the New Relic monitoring portal associated with our account: When we do this a new browser tab will launch with the New Relic admin tool loaded within it: We can now see insights into how our app is performing – without having to have written a single line of monitoring code.  The New Relic service provides a ton of great built-in monitoring features allowing us to quickly see: Performance times (including browser rendering speed) for the overall site and individual pages.  You can optionally set alert thresholds to trigger if the speed does not meet a threshold you specify. Information about where in the world your customers are hitting the site from (and how performance varies by region) Details on the latency performance of external services your web apps are using (for example: SQL, Storage, Twitter, etc) Error information including call stack details for exceptions that have occurred at runtime SQL Server profiling information – including which queries executed against your database and what their performance was And a whole bunch more… The cool thing about New Relic is that you don’t need to write monitoring code within your application to get all of the above reports (plus a lot more).  The New Relic agent automatically enables the CLR profiler within applications and automatically captures the information necessary to identify these.  This makes it super easy to get started and immediately have a rich developer analytics view for your solutions with very little effort. If you haven’t tried New Relic out yet with Windows Azure I recommend you do so – I think you’ll find it helps you build even better cloud applications.  Following the above steps will help you get started and deliver you a really good application monitoring solution in only minutes. Service Bus: Support for partitioned queues and topics With today’s release, we are enabling support within Service Bus for partitioned queues and topics. Enabling partitioning enables you to achieve a higher message throughput and better availability from your queues and topics. Higher message throughput is achieved by implementing multiple message brokers for each partitioned queue and topic.  The  multiple messaging stores will also provide higher availability. You can create a partitioned queue or topic by simply checking the Enable Partitioning option in the custom create wizard for a Queue or Topic: Read this article to learn more about partitioned queues and topics and how to take advantage of them today. Billing: New Billing Alert Service Today’s Windows Azure update enables a new Billing Alert Service Preview that enables you to get proactive email notifications when your Windows Azure bill goes above a certain monetary threshold that you configure.  This makes it easier to manage your bill and avoid potential surprises at the end of the month. With the Billing Alert Service Preview, you can now create email alerts to monitor and manage your monetary credits or your current bill total.  To set up an alert first sign-up for the free Billing Alert Service Preview.  Then visit the account management page, click on a subscription you have setup, and then navigate to the new Alerts tab that is available: The alerts tab allows you to setup email alerts that will be sent automatically once a certain threshold is hit.  For example, by clicking the “add alert” button above I can setup a rule to send myself email anytime my Windows Azure bill goes above $100 for the month: The Billing Alert Service will evolve to support additional aspects of your bill as well as support multiple forms of alerts such as SMS.  Try out the new Billing Alert Service Preview today and give us feedback. Summary Today’s Windows Azure release enables a ton of great new scenarios, and makes building applications hosted in the cloud even easier. If you don’t already have a Windows Azure account, you can sign-up for a free trial and start using all of the above features today.  Then visit the Windows Azure Developer Center to learn more about how to build apps with it. Hope this helps, Scott P.S. In addition to blogging, I am also now using Twitter for quick updates and to share links. Follow me at: twitter.com/scottgu

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• Event Logging in LINQ C# .NET

  The first thing you'll want to do before using this code is to create a table in your database called TableHistory: CREATE TABLE [dbo].[TableHistory] (     [TableHistoryID] [int] IDENTITY NOT NULL ,     [TableName] [varchar] (50) NOT NULL ,     [Key1] [varchar] (50) NOT NULL ,     [Key2] [varchar] (50) NULL ,     [Key3] [varchar] (50) NULL ,     [Key4] [varchar] (50) NULL ,     [Key5] [varchar] (50) NULL ,     [Key6] [varchar] (50)NULL ,     [ActionType] [varchar] (50) NULL ,     [Property] [varchar] (50) NULL ,     [OldValue] [varchar] (8000) NULL ,     [NewValue] [varchar] (8000) NULL ,     [ActionUserName] [varchar] (50) NOT NULL ,     [ActionDateTime] [datetime] NOT NULL ) Once you have created the table, you'll need to add it to your custom LINQ class (which I will refer to as DboDataContext), thus creating the TableHistory class. Then, you'll need to add the History.cs file to your project. You'll also want to add the following code to your project to get the system date: public partial class DboDataContext{ [Function(Name = "GetDate", IsComposable = true)] public DateTime GetSystemDate() { MethodInfo mi = MethodBase.GetCurrentMethod() as MethodInfo; return (DateTime)this.ExecuteMethodCall(this, mi, new object[] { }).ReturnValue; }}private static Dictionary<type,> _cachedIL = new Dictionary<type,>();public static T CloneObjectWithIL<t>(T myObject){ Delegate myExec = null; if (!_cachedIL.TryGetValue(typeof(T), out myExec)) { // Create ILGenerator DynamicMethod dymMethod = new DynamicMethod("DoClone", typeof(T), new Type[] { typeof(T) }, true); ConstructorInfo cInfo = myObject.GetType().GetConstructor(new Type[] { }); ILGenerator generator = dymMethod.GetILGenerator(); LocalBuilder lbf = generator.DeclareLocal(typeof(T)); //lbf.SetLocalSymInfo("_temp"); generator.Emit(OpCodes.Newobj, cInfo); generator.Emit(OpCodes.Stloc_0); foreach (FieldInfo field in myObject.GetType().GetFields( System.Reflection.BindingFlags.Instance | System.Reflection.BindingFlags.Public | System.Reflection.BindingFlags.NonPublic)) { // Load the new object on the eval stack... (currently 1 item on eval stack) generator.Emit(OpCodes.Ldloc_0); // Load initial object (parameter) (currently 2 items on eval stack) generator.Emit(OpCodes.Ldarg_0); // Replace value by field value (still currently 2 items on eval stack) generator.Emit(OpCodes.Ldfld, field); // Store the value of the top on the eval stack into // the object underneath that value on the value stack. // (0 items on eval stack) generator.Emit(OpCodes.Stfld, field); } // Load new constructed obj on eval stack -> 1 item on stack generator.Emit(OpCodes.Ldloc_0); // Return constructed object. --> 0 items on stack generator.Emit(OpCodes.Ret); myExec = dymMethod.CreateDelegate(typeof(Func<t,>)); _cachedIL.Add(typeof(T), myExec); } return ((Func<t,>)myExec)(myObject);}I got both of the above methods off of the net somewhere (maybe even from CodeProject), but it's been long enough that I can't recall where I got them.Explanation of the History ClassThe History class records changes by creating a TableHistory record, inserting the values for the primary key for the table being modified into the Key1, Key2, ..., Key6 columns (if you have more than 6 values that make up a primary key on any table, you'll want to modify this), setting the type of change being made in the ActionType column (INSERT, UPDATE, or DELETE), old value and new value if it happens to be an update action, and the date and Windows identity of the user who made the change.Let's examine what happens when a call is made to the RecordLinqInsert method:public static void RecordLinqInsert(DboDataContext dbo, IIdentity user, object obj){ TableHistory hist = NewHistoryRecord(obj); hist.ActionType = "INSERT"; hist.ActionUserName = user.Name; hist.ActionDateTime = dbo.GetSystemDate(); dbo.TableHistories.InsertOnSubmit(hist);}private static TableHistory NewHistoryRecord(object obj){ TableHistory hist = new TableHistory(); Type type = obj.GetType(); PropertyInfo[] keys; if (historyRecordExceptions.ContainsKey(type)) { keys = historyRecordExceptions[type].ToArray(); } else { keys = type.GetProperties().Where(o => AttrIsPrimaryKey(o)).ToArray(); } if (keys.Length > KeyMax) throw new HistoryException("object has more than " + KeyMax.ToString() + " keys."); for (int i = 1; i <= keys.Length; i++) { typeof(TableHistory) .GetProperty("Key" + i.ToString()) .SetValue(hist, keys[i - 1].GetValue(obj, null).ToString(), null); } hist.TableName = type.Name; return hist;}protected static bool AttrIsPrimaryKey(PropertyInfo pi){ var attrs = from attr in pi.GetCustomAttributes(typeof(ColumnAttribute), true) where ((ColumnAttribute)attr).IsPrimaryKey select attr; if (attrs != null && attrs.Count() > 0) return true; else return false;}RecordLinqInsert takes as input a data context which it will use to write to the database, the user, and the LINQ object to be recorded (a single object, for instance, a Customer or Order object if you're using AdventureWorks). It then calls the NewHistoryRecord method, which uses LINQ to Objects in conjunction with the AttrIsPrimaryKey method to pull all the primary key properties, set the Key1-KeyN properties of the TableHistory object, and return the new TableHistory object. The code would be called in an application, like so: Continue span.fullpost {display:none;}

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• Tuples vs. Anonymous Types vs. Expando object. (in regards to LINQ queries)

  - by punkouter

  I am a beginner who finally started understanding anonymous types. (see old post http://stackoverflow.com/questions/3010147/what-is-the-return-type-for-a-anonymous-linq-query-select-what-is-the-best-way-t) So in LINQ queries you form the type of return value you want within the linq query right? It seems the way to do this is anonymous type right? Can someone explain to me if and when I could use a Tuple/Expando object instead? They all seem very simliar?

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• How does C++ free the memory when a constructor throws an exception and a custom new is used

  - by Joshua

  I see the following constructs: new X will free the memory if X constructor throws. operator new() can be overloaded. The canonical definition of an operator new overload is void *operator new(heap h) and the corrisponding operator delete. The most common operator new overload is pacement new, which is void *operator new(void *p) { return p; } You almost always cannot call delete on the pointer given to placement new. This leads to a single question. How is memory cleaned up when X constructor throws and an overloaded new is used?

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• LINQ to SQL : Too much CPU Usage: What happens when there are multiple users.

  - by soldieraman

  I am using LINQ to SQL and seeing my CPU Usage sky rocketting. See below screenshot. I have three questions What can I do to reduce this CPU Usage. I have done profiling and basically removed everything. Will making every LINQ to SQL statement into a compiled query help? I also find that even with compiled queries simple statements like ByID() can take 3 milliseconds on a server with 3.25GB RAM 3.17GHz - this will just become slower on a less powerful computer. Or will the compiled query get faster the more it is used? The CPU Usage (on the local server goes to 12-15%) for a single user will this multiply with the number of users accessing the server - when the application is put on a live server. i.e. 2 users at a time will mean 15*2 = 30% CPU Usage. If this is the case is my application limited to maximum 4-5 users at a time then. Or doesnt LINQ to SQL .net share some CPU usage.

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• Linq Query Performance , comparing Compiled query vs Non-Compiled.

  - by AG.

  Hello Guys, I was wondering if i extract the common where clause query into a common expression would it make my query much faster, if i have say something like 10 linq queries on a collection with exact same 1st part of the where clause. I have done a small example to explain a bit more . public class Person { public string First { get; set; } public string Last { get; set; } public int Age { get; set; } public String Born { get; set; } public string Living { get; set; } } public sealed class PersonDetails : List<Person> { } PersonDetails d = new PersonDetails(); d.Add(new Person() {Age = 29, Born = "Timbuk Tu", First = "Joe", Last = "Bloggs", Living = "London"}); d.Add(new Person() { Age = 29, Born = "Timbuk Tu", First = "Foo", Last = "Bar", Living = "NewYork" }); Expression<Func<Person, bool>> exp = (a) => a.Age == 29; Func<Person, bool> commonQuery = exp.Compile(); var lx = from y in d where commonQuery.Invoke(y) && y.Living == "London" select y; var bx = from y in d where y.Age == 29 && y.Living == "NewYork" select y; Console.WriteLine("All Details {0}, {1}, {2}, {3}, {4}", lx.Single().Age, lx.Single().First , lx.Single().Last, lx.Single().Living, lx.Single().Born ); Console.WriteLine("All Details {0}, {1}, {2}, {3}, {4}", bx.Single().Age, bx.Single().First, bx.Single().Last, bx.Single().Living, bx.Single().Born); So can some of the guru's here give me some advice if it would be a good practice to write query like var lx = "Linq Expression " or var bx = "Linq Expression" ? Any inputs would be highly appreciated. Thanks, AG

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