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• Are there size limitations to the .NET Assembly format?

  - by McKAMEY

  We ran into an interesting issue that I've not experienced before. We have a large scale production ASP.NET 3.5 SP1 Web App Project in Visual Studio 2008 SP1 which gets compiled and deployed using a Website Deployment Project. Everything has worked fine for the last year, until after a check-in yesterday the app started critically failing with BadImageFormatException. The check-in in question doesn't change anything particularly special and the errors are coming from areas of the app not even changed. Using Reflector we inspected the offending methods to find that there were garbage strings in the code (which .NET Reflector humorously interpreted as Chinese characters). We have consistently reproduced this on several machines so it does not appear to be hardware related. Further inspection showed that those garbage strings did not exist in the Assemblies used as inputs to aspnet_merge.exe during deployment. aspnet_merge.exe / Web Deployment Project Output Assemblies Properties: Merge all outputs to a single assembly Merge each individual folder output to its own assembly Merge all pages and control outputs to a single assembly Create a separate assembly for each page and control output In the web deployment project properties if we set the merge options to the first option ("Merge all outputs to a single assembly") we experience the issue, yet all of the other options work perfectly! My question: does anyone know why this is happening? Is there a size-limit to aspnet_merge.exe's capabilities (the resulting merged DLL is around 19.3 MB)? Are there any other known issues with merging the output of WAPs? I would love it if any Assembly format / aspnet_merge.exe gurus know about any such limitations like this. Seems to me like a 25MB Assembly, while big, isn't outrageous.

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• Xen DomU on DRBD device: barrier errors

  - by Halfgaar

  I'm testing setting up a Xen DomU with a DRBD storage for easy failover. Most of the time, immediatly after booting the DomU, I get an IO error: [ 3.153370] EXT3-fs (xvda2): using internal journal [ 3.277115] ip_tables: (C) 2000-2006 Netfilter Core Team [ 3.336014] nf_conntrack version 0.5.0 (3899 buckets, 15596 max) [ 3.515604] init: failsafe main process (397) killed by TERM signal [ 3.801589] blkfront: barrier: write xvda2 op failed [ 3.801597] blkfront: xvda2: barrier or flush: disabled [ 3.801611] end_request: I/O error, dev xvda2, sector 52171168 [ 3.801630] end_request: I/O error, dev xvda2, sector 52171168 [ 3.801642] Buffer I/O error on device xvda2, logical block 6521396 [ 3.801652] lost page write due to I/O error on xvda2 [ 3.801755] Aborting journal on device xvda2. [ 3.804415] EXT3-fs (xvda2): error: ext3_journal_start_sb: Detected aborted journal [ 3.804434] EXT3-fs (xvda2): error: remounting filesystem read-only [ 3.814754] journal commit I/O error [ 6.973831] init: udev-fallback-graphics main process (538) terminated with status 1 [ 6.992267] init: plymouth-splash main process (546) terminated with status 1 The manpage of drbdsetup says that LVM (which I use) doesn't support barriers (better known as tagged command queuing or native command queing), so I configured the drbd device not to use barriers. This can be seen in /proc/drbd (by "wo:f, meaning flush, the next method drbd chooses after barrier): 3: cs:Connected ro:Primary/Secondary ds:UpToDate/UpToDate C r---- ns:2160152 nr:520204 dw:2680344 dr:2678107 al:3549 bm:9183 lo:0 pe:0 ua:0 ap:0 ep:1 wo:f oos:0 And on the other host: 3: cs:Connected ro:Secondary/Primary ds:UpToDate/UpToDate C r---- ns:0 nr:2160152 dw:2160152 dr:0 al:0 bm:8052 lo:0 pe:0 ua:0 ap:0 ep:1 wo:f oos:0 I also enabled the option disable_sendpage, as per the drbd docs: cat /sys/module/drbd/parameters/disable_sendpage Y I also tried adding barriers=0 to fstab as mount option. Still it sometimes says: [ 58.603896] blkfront: barrier: write xvda2 op failed [ 58.603903] blkfront: xvda2: barrier or flush: disabled I don't even know if ext3 has a nobarrier option. And, because only one of my storage systems is battery backed, it would not be smart anyway. Why does it still compain about barriers when I disabled that? Both host are: Debian: 6.0.4 uname -a: Linux 2.6.32-5-xen-amd64 drbd: 8.3.7 Xen: 4.0.1 Guest: Ubuntu 12.04 LTS uname -a: Linux 3.2.0-24-generic pvops drbd resource: resource drbdvm { meta-disk internal; device /dev/drbd3; startup { # The timeout value when the last known state of the other side was available. 0 means infinite. wfc-timeout 0; # Timeout value when the last known state was disconnected. 0 means infinite. degr-wfc-timeout 180; } syncer { # This is recommended only for low-bandwidth lines, to only send those # blocks which really have changed. #csums-alg md5; # Set to about half your net speed rate 60M; # It seems that this option moved to the 'net' section in drbd 8.4. (later release than Debian has currently) verify-alg md5; } net { # The manpage says this is recommended only in pre-production (because of its performance), to determine # if your LAN card has a TCP checksum offloading bug. #data-integrity-alg md5; } disk { # Detach causes the device to work over-the-network-only after the # underlying disk fails. Detach is not default for historical reasons, but is # recommended by the docs. # However, the Debian defaults in drbd.conf suggest the machine will reboot in that event... on-io-error detach; # LVM doesn't support barriers, so disabling it. It will revert to flush. Check wo: in /proc/drbd. If you don't disable it, you get IO errors. no-disk-barrier; } on host1 { # universe is a VG disk /dev/universe/drbdvm-disk; address 10.0.0.1:7792; } on host2 { # universe is a VG disk /dev/universe/drbdvm-disk; address 10.0.0.2:7792; } } DomU cfg: bootloader = '/usr/lib/xen-default/bin/pygrub' vcpus = '2' memory = '512' # # Disk device(s). # root = '/dev/xvda2 ro' disk = [ 'phy:/dev/drbd3,xvda2,w', 'phy:/dev/universe/drbdvm-swap,xvda1,w', ] # # Hostname # name = 'drbdvm' # # Networking # # fake IP for posting vif = [ 'ip=1.2.3.4,mac=00:16:3E:22:A8:A7' ] # # Behaviour # on_poweroff = 'destroy' on_reboot = 'restart' on_crash = 'restart' In my test setup: the primary host's storage is 9650SE SATA-II RAID PCIe with battery. The secondary is software RAID1. Isn't DRBD+Xen widely used? With these problems, it's not going to work.

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• Tridion New UI Preview Site is not reflecting with the changes unless pulished

  - by Ram G

  I have new UI setup and noticing that when ever I update a page it is not refreshing with the updated changes. I do not see either the page_{sessionId/GUID}.aspx created either. Checked the session preview DB and I see the changes in PAGE_CONTENT table with new rendered content, so seems like session preview is working fine but the Preview site is not able to get the changes and refresh the UI. I have checked all the preview handlers and mappings for .aspx and made sure they are correct in web.config. Any thoughts on why the preview site not showing up the changes? I have the session preview DB setup in cd_storage_conf.xml. <StorageBindings> <Bundle src="preview_dao_bundle.xml"/> </StorageBindings> <Wrappers> <Wrapper Name="SessionWrapper"> <Timeout>120000</Timeout> <Storage Type="persistence" Id="db-session-webservice" dialect="MSSQL" Class="com.tridion.storage.persistence.JPADAOFactory"> <Pool Type="jdbc" Size="5" MonitorInterval="60" IdleTimeout="120" CheckoutTimeout="120" /> <DataSource Class="com.microsoft.sqlserver.jdbc.SQLServerDataSource"> <Property Name="serverName" Value="localhost" /> <Property Name="portNumber" Value="1433" /> <Property Name="databaseName" Value="Tridion_Broker_SessionPreview" /> <Property Name="user" Value="usr" /> <Property Name="password" Value="pwd" /> </DataSource> </Storage> </Wrapper> </Wrappers> web.config (handlers): <add verb="GET" path="*.htm" type="Tridion.ContentDelivery.Preview.Web.StaticFileHandler" /> <add verb="GET" path="*.jpg" type="Tridion.ContentDelivery.Preview.Web.StaticFileHandler" /> <add verb="GET" path="*.png" type="Tridion.ContentDelivery.Preview.Web.StaticFileHandler" /> <add verb="GET" path="*.aspx" type="Tridion.ContentDelivery.Preview.Web.StaticFileHandler" /> <add verb="GET" path="*.html" type="Tridion.ContentDelivery.Preview.Web.StaticFileHandler" /> <add name="Tridion.ContentDelivery.Preview.Web.PreviewContentModule" type="Tridion.ContentDelivery.Preview.Web.PreviewContentModule" /> Log (timestamp and DEBUG prefix removed): ClaimStore - put: uri=taf:session:id, value=tridion_db59279b-7d37-4b2e-ad98-eaaa6af7038e ClaimStore - put: uri=taf:session:id, value=tridion_db59279b-7d37-4b2e-ad98-eaaa6af7038e ClaimStore - put: uri=taf:tracking:id, value=tridion_d1fa1017-a28d-4f48-a790-b74f78c69314 ClaimStore - put: uri=taf:tracking:id, value=tridion_d1fa1017-a28d-4f48-a790-b74f78c69314 SearchClaimProcessor - No match found for referrer string http://uidemo.practice.com/en/Product/musk.aspx SearchClaimProcessor - No match found for referrer string http://uidemo.practice.com/en/Product/musk.aspx ClaimStore - put: uri=taf:claim:ambientdata:footprintcartridge:devicetype, value=Desktop ClaimStore - put: uri=taf:claim:ambientdata:footprintcartridge:devicetype, value=Desktop ClaimStore - put: uri=taf:claim:ambientdata:footprintcartridge:mobiledevice, value=NotMobile ClaimStore - put: uri=taf:claim:ambientdata:footprintcartridge:acceptlanguage, value=en-US ClaimStore - put: uri=taf:claim:ambientdata:footprintcartridge:mobiledevice, value=NotMobile ClaimStore - put: uri=taf:claim:ambientdata:footprintcartridge:acceptlanguage, value=en-US PageHandler - The session wrappers are correctly installed. Any thoughts/pointers on what might be going wrong...? (sorry for the long post)

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• Asp.net Crawler Webresponse Operation Timed out.

  - by Leon

  Hi I have built a simple threadpool based web crawler within my web application. Its job is to crawl its own application space and build a Lucene index of every valid web page and their meta content. Here's the problem. When I run the crawler from a debug server instance of Visual Studio Express, and provide the starting instance as the IIS url, it works fine. However, when I do not provide the IIS instance and it takes its own url to start the crawl process(ie. crawling its own domain space), I get hit by operation timed out exception on the Webresponse statement. Could someone please guide me into what I should or should not be doing here? Here is my code for fetching the page. It is executed in the multithreaded environment. private static string GetWebText(string url) { string htmlText = ""; HttpWebRequest request = (HttpWebRequest)HttpWebRequest.Create(url); request.UserAgent = "My Crawler"; using (WebResponse response = request.GetResponse()) { using (Stream stream = response.GetResponseStream()) { using (StreamReader reader = new StreamReader(stream)) { htmlText = reader.ReadToEnd(); } } } return htmlText; } And the following is my stacktrace: at System.Net.HttpWebRequest.GetResponse() at CSharpCrawler.Crawler.GetWebText(String url) in c:\myAppDev\myApp\site\App_Code\CrawlerLibs\Crawler.cs:line 366 at CSharpCrawler.Crawler.CrawlPage(String url, List1 threadCityList) in c:\myAppDev\myApp\site\App_Code\CrawlerLibs\Crawler.cs:line 105 at CSharpCrawler.Crawler.CrawlSiteBuildIndex(String hostUrl, String urlToBeginSearchFrom, List1 threadCityList) in c:\myAppDev\myApp\site\App_Code\CrawlerLibs\Crawler.cs:line 89 at crawler_Default.threadedCrawlSiteBuildIndex(Object threadedCrawlerObj) in c:\myAppDev\myApp\site\crawler\Default.aspx.cs:line 108 at System.Threading.QueueUserWorkItemCallback.WaitCallback_Context(Object state) at System.Threading.ExecutionContext.runTryCode(Object userData) at System.Runtime.CompilerServices.RuntimeHelpers.ExecuteCodeWithGuaranteedCleanup(TryCode code, CleanupCode backoutCode, Object userData) at System.Threading.ExecutionContext.RunInternal(ExecutionContext executionContext, ContextCallback callback, Object state) at System.Threading.ExecutionContext.Run(ExecutionContext executionContext, ContextCallback callback, Object state, Boolean ignoreSyncCtx) at System.Threading.QueueUserWorkItemCallback.System.Threading.IThreadPoolWorkItem.ExecuteWorkItem() at System.Threading.ThreadPoolWorkQueue.Dispatch() at System.Threading._ThreadPoolWaitCallback.PerformWaitCallback() Thanks and cheers, Leon.

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• Efficient cron job utilizing Zend_Mail_Storage_Imap.

  - by fireeyedboy

  I'm new to the IMAP protocol and Zend_Mail_Storage and I'm writing a small php script for a cron job that should regularly poll an IMAP account and check for new messages, and send an e-mail if new messages have arrived. As you can imagine, I want to only poll the IMAP account for relevant messages, and I only want to send a new e-mail if new messages have arrived since the last polled new message. So I thought of keeping track of the last message I polled with some unique identifier for a message. But I'm a bit uncertain about whether the methods I want to utilize for this do what I expect them to do though. So my questions are: Does the iterator position of Zend_Mail_Storage_Imap actually resemble some IMAP unique identifier for messages, or is it simply only and internal position of Zend_Mail_Storage_Abstract? For instance, if I tell it to seek() to message 5 (which I stored from an earlier session) will it indeed seek to the appropriate message on the IMAP server, even if for instance messages have been deleted since last session? Would keeping track of this latest polled message id in a file suffice for a cron job that, say, polls the account every 5 or 10 minutes? Or is this too naive, and should I be using a database for instance. Or is there maybe a much easier way to keep track of such state with Zend_Mail_Storage_Abstract? Also, do I need to poll every IMAP folder? Or is everything accumulated when I poll INBOX? If you could shed some light on any of these matters, I'ld appreciate it. Thanks in advance.

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• Why can't I create a database in an empty ASP MVC 2 project using Project->Add->New Item->SQL Server

  - by Dr Dork

  I'm diving head first into ASP MVC and am playing around with creating and manipulating a database. I did a search and found this tutorial for creating a database, however when I follow it, I get this error when trying to add a new database to my fresh, empty ASP MVC 2 project... A network-related or instance-specific error occurred while establishing a connection to SQL Server. The server was not found or was not accessible. Verify that the instance name is correct and that SQL Server is configured to allow remote connections. (provider: SQL Network Interfaces, error: 26 - Error Locating Server/Instance Specified) The only requirement the tutorial mentioned was SQL Server Express, but when I went to download it, it said it was already installed. I'm assuming it was part of the VS 2010 RC I installed and am running. So I don't know what else I need if I am missing something. This is all new to me, so I'm sure I'm missing something obvious here and after I'm done posting this question, I plan to do some more research into the topic of databases and how they work with ASP MVC. In the meantime, I was you could help me answer a couple high level questions... What am I missing/forgetting to do that is causing this error? Any suggestions for good resources/tutorials that focus on using databases with ASP MVC? I've done a lot of database programming in the past, so I'm familiar with the concepts of relational databases and the SQL language. I wish I could find a good resource for learning how to work with them in an ASP dev environment, as well as a good breakdown of all the related technologies used for working with them (i.e. LINQ to SQL). Thanks so much in advance for all your help! I'm going to start researching these questions right now.

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• raw_id_fields for modelforms

  - by nbv4

  I have a modelform which has one field that is a ForeignKey value to a model which as 40,000 rows. The default modelform tries to create a select box with 40,000 options, which, to say the least is not ideal. Even more so when this modelform is used in a formset factory! In the admin, this is easiely avoidable by using "raw_id_fields", but there doesn't seem to be a modelform equivalent. How can I do this? Here is my modelform: class OpBaseForm(ModelForm): base = forms.CharField() class Meta: model = OpBase exclude = ['operation', 'routes'] extra = 0 raw_id_fields = ('base', ) #does nothing The first bolded line works by not creating the huge unwieldy selectbox, but when I try to save a fieldset of this form, I get the error: "OpBase.base" must be a "Base" instance. In order for the modelform to be saved, 'base' needs to be a Base instance. Apparently, a string representation of a Base primary key isn't enough (at least not automatically). I need some kind of mechanism to change the string that is given my the form, to a Base instance. And this mechanism has to work in a formset. Any ideas? If only raw_id_fields would work, this would be easy as cake. But as far as I can tell, it only is available in the admin.

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• regular expression for indian vehicle number

  - by I Like PHP

  i need validation for indian vehicle NUMBER here are condition list let expression is (x)(y)(z)(m)(a)(b)(c) 1. (x) contains only alphabets of length 2. 2. (y) may be - or single space ' ' 3. (z) contains only numbers of length 2 4. (m) may be or , or single space ' ' 5. length of (a) can be 2 or 3. contains alphanumeric value with minimum one alphabetic character. 6. (b) may be - or single space ' ' ( similar to (y) ) 7. (c) contains only numbers of length 4 i show you the various examples of vehicle number valid number RJ-14,NL-1234 RJ-01,4M-5874 RJ-07,14M-2345 RJ 07,3M 2345 RJ-07,3M-8888 RJ 07 4M 2345 RJ 07,4M 2933 invalid number RJ-07 3M 1234 ( both (y) and (b) should be same). RJ-07 M3-1234 ((a) must ends with alphabat). rj-07 M3-123 ( length of (c) must be 4).

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• Quering XElements for children with children attributes.

  - by Arnej65

  Here is the XML outline: <Root> <Thing att="11"> <Child lang="e"> <record></record> <record></record> <record></record> </Child > <Child lang="f"> <record></record> <record></record> <record></record> </Child > </Thing> </Root> I have the following: TextReader reader = new StreamReader(Assembly.GetExecutingAssembly() .GetManifestResourceStream(FileName)); var data = XElement.Load(reader); foreach (XElement single in Data.Elements()) { // english records var EnglishSet = (from e in single.Elements("Child") where e.Attribute("lang").Equals("e") select e.Value).FirstOrDefault(); } But I'm getting back nothing. I want to be able to for Each "Thing" select the "Child" where the attribute "lang" equals a value. I have also tried this, which has not worked. var FrenchSet = single.Elements("Child") .Where(y => y.Attribute("lang").Equals("f")) .Select(x => x.Value).FirstOrDefault();

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• JAXB does not call setter when unmarshalling objects

  - by Yaneeve

  Hi all, I am using JAXB 2.0 JDK 6 in order to unmarshall an XML instance into POJOs. In order to add some custom validation I have inserted a validation call into the setter of a property, yet despite it being private, it seems that the unmarshaller does not call the setter but directly modifies the private field. It is crucial to me that the custom validation occurs for this specific field every unmarshall call. What should I do? Code: @XmlAccessorType(XmlAccessType.FIELD) @XmlType(name = "LegalParams", propOrder = { "value" }) public class LegalParams { private static final Logger LOG = Logger.getLogger(LegalParams.class); @XmlTransient private LegalParamsValidator legalParamValidator; public LegalParams() { try { WebApplicationContext webApplicationContext = ContextLoader.getCurrentWebApplicationContext(); LegalParamsFactory legalParamsFactory = (LegalParamsFactory) webApplicationContext.getBean("legalParamsFactory"); HttpSession httpSession = SessionHolder.getInstance().get(); legalParamValidator = legalParamsFactory.newLegalParamsValidator(httpSession); } catch (LegalParamsException lpe) { LOG.warn("Validator related error occurred while attempting to construct a new instance of LegalParams"); throw new IllegalStateException("LegalParams creation failure", lpe); } catch (Exception e) { LOG.warn("Spring related error occurred while attempting to construct a new instance of LegalParams"); throw new IllegalStateException("LegalParams creation failure", e); } } @XmlValue private String value; /** * Gets the value of the value property. * * @return * possible object is * {@link String } * */ public String getValue() { return value; } /** * Sets the value of the value property. * * @param value * allowed object is * {@link String } * @throws TestCaseValidationException * */ public void setValue(String value) throws TestCaseValidationException { legalParamValidator.assertValid(value); this.value = value; } }

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• Industry-style practices for increasing productivity in a small scientific environment

  - by drachenfels

  Hi, I work in a small, independent scientific lab in a university in the United States, and it has come to my notice that, compared with a lot of practices that are ostensibly followed in the industry, like daily checkout into a version control system, use of a single IDE/editor for all languages (like emacs), etc, we follow rather shoddy programming practices. So, I was thinking of getting together all my programs, scripts, etc, and building a streamlined environment to increase productivity. I'd like suggestions from people on Stack Overflow for the same. Here is my primary plan.: I use MATLAB, C and Python scripts, and I'd like to edit, compile them from a single editor, and ensure correct version control. (questions/things for which I'd like suggestions are in italics) 1] Install Cygwin, and get it to work well with Windows so I can use git or a similar version control system (is there a DVCS which can work directly from the windows CLI, so I can skip the Cygwin step?). 2] Set up emacs to work with C, Python, and MATLAB files, so I can edit and compile all three at once from a single editor (say, emacs) (I'm not very familiar with the emacs menu, but is there a way to set the path to the compiler for certain languages? I know I can Google this, but emacs documentation has proved very hard for me to read so far, so I'd appreciate it if someone told me in simple language) 3] Start checking in code at the end of each day or half-day so as to maintain a proper path of progress of my code (two questions), can you checkout files directly from emacs? is there a way to checkout LabVIEW files into a DVCS like git? Lastly, I'd like to apologize for the rather vague nature of the question, and hope I shall learn to ask better questions over time. I'd appreciate it if people gave their suggestions, though, and point to any resources which may help me learn.

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• StructureMap resolve dependency through injection instead of service location

  - by Chris Marisic

  In my project I register many ISerializers implementations with the assembly scanner. FWIW this is the code that registers my ISerializers Scan(scanner => { scanner.AssemblyContainingType<ISerializer>(); scanner.AddAllTypesOf<ISerializer>().NameBy(type => type.Name); scanner.WithDefaultConventions(); }); Which then correctly registers ISerializer (...ISerializer) Scoped as: Transient JsonSerializer Configured Instance of ...JsonSerializer BsonSerializer Configured Instance of ...BsonSerializer And so forth. Currently the only way I've been able to figure out how to resolve the serializer I want is to hardcode a service location call with jsonSerializer = ObjectFactory.GetNamedInstance<ISerializer>("JsonSerializer"); Now I know in my class that I specifically want the jsonSerializer so is there a way to configure a rule or similar that says for ISerializer's to connect the named instance based on the property name? So that I could have MySomeClass(ISerializer jsonSerializer, ....) And StructureMap correctly resolve this scenario? Or am I approaching this wrong and perhaps I should just register the concrete type that implements ISerializer and then just specifically use MySomeClass(JsonSerializer jsonSerializer, ....) for something along these lines with the concrete class?

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• Factory Method Pattern clarification

  - by nettguy

  My understanding of Factory Method Pattern is (Correct me if i am wrong) Factory Method Pattern "Factory Method allow the client to delegates the product creation (Instance Creation) to the subclass". There are two situation in which we can go for creating Factory Method pattern. (i) When the client is restricted to the product (Instance) creation. (ii) There are multiple products available.But a decision to be made which product instance need to be returned. If you want to create Abstract Method pattern You need to have abstract product Concrete Product Factory Method to return the appropriate product. Example : public enum ORMChoice { L2SQL, EFM, LS, Sonic } //Abstract Product public interface IProduct { void ProductTaken(); } //Concrete Product public class LinqtoSql : IProduct { public void ProductTaken() { Console.WriteLine("OR Mapping Taken:LinqtoSql"); } } //concrete product public class Subsonic : IProduct { public void ProductTaken() { Console.WriteLine("OR Mapping Taken:Subsonic"); } } //concrete product public class EntityFramework : IProduct { public void ProductTaken() { Console.WriteLine("OR Mapping Taken:EntityFramework"); } } //concrete product public class LightSpeed : IProduct { public void ProductTaken() { Console.WriteLine("OR Mapping Taken :LightSpeed"); } } public class Creator { //Factory Method public IProduct ReturnORTool(ORMChoice choice) { switch (choice) { case ORMChoice.EFM:return new EntityFramework(); break; case ORMChoice.L2SQL:return new LinqtoSql(); break; case ORMChoice.LS:return new LightSpeed(); break; case ORMChoice.Sonic:return new Subsonic(); break; default: return null; } } } **Client** Button_Click() { Creator c = new Creator(); IProduct p = c.ReturnORTool(ORMChoice.L2SQL); p.ProductTaken(); } Is my understanding of Factory Method is correct?

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• Why can't perfmon see instances of my custom performance counter?

  - by spoulson

  I'm creating some custom performance counters for an application. I wrote a simple C# tool to create the categories and counters. For example, the code snippet below is basically what I'm running. Then, I run a separate app that endlessly refreshes the raw value of the counter. While that runs, the counter and dummy instance are seen locally in perfmon. The problem I'm having is that the monitoring system we use can't see the instances in the multi-instance counter I've created when viewing remotely from another server. When using perfmon to browse the counters, I can see the category and counters, but the instances box is grayed out and I can't even select "All instances", nor can I click "Add". Using other access methods, like [typeperf][1] exhibit similar issues. I'm not sure if this is a server or code issue. This is only reproducible in the production environment where I need it. On my desktop and development servers, it works great. I'm a local admin on all servers. CounterCreationDataCollection collection = new CounterCreationDataCollection(); var category_name = "My Application"; var counter_name = "My counter name"; CounterCreationData ccd = new CounterCreationData(); ccd.CounterType = PerformanceCounterType.RateOfCountsPerSecond64; ccd.CounterName = counter_name; ccd.CounterHelp = counter_name; collection.Add(ccd); PerformanceCounterCategory.Create(category_name, category_name, PerformanceCounterCategoryType.MultiInstance, collection); Then, in a separate app, I run this to generate dummy instance data: var pc = new PerformanceCounter(category_name, counter_name, instance_name, false); while (true) { pc.RawValue = 0; Thread.Sleep(1000); }

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• Parsing multibyte string in PHP

  - by Petr Peller

  I would like to write a (HTML) parser based on state machine but I have doubts how to acctually read/use an input. I decided to load the whole input into one string and then work with it as with an array and hold its index as current parsing position. There would be no problems with single-byte encoding, but in multi-byte encoding each value does not represent a character, but a byte of a character. Example: $mb_string = 'žšcr'; //4 multi-byte characters in UTF-8 for($i=0; $i < 4; $i++) { echo $mb_string[$i], PHP_EOL; } Outputs: L ž L A This means I cannot iterate through the string in a loop to check single characters, because I never know if I am in the middle of an character or not. So the questions are: How do I multi-byte safe read a single character from a string in a performance friendly way? Is it good idea to work with the string as it was an array in this case? How would you read the input?

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• How do attribute classes work?

  - by AaronLS

  My searches keep turning up only guides explaining how to use and apply attributes to a class. I want to learn how to create my own attribute classes and the mechanics of how they work. How are attribute classes instantiated? Are they instantiated when the class they are applied to is instantiated? Is one instantiated for each class instantiated that it is applied to? E.g. if I apply the SerializableAttribute class to a MyData class, and I instantiate 5 MyData instances, will there be 5 instances of the SerializbleAttribute class created behind the scenes? Or is there just one instance shared between all of them? How do attribute class instances access the class they are associated with? How does a SerializableAttribute class access the class it is applied to so that it can serialize it's data? Does it have some sort of SerializableAttribute.ThisIsTheInstanceIAmAppliedTo property? :) Or does it work in the reverse direction that whenever I serialize something, the Serialize function I pass the MyClass instance to will reflectively go through the Attributes and find the SerialiableAttribute instance?

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• instantiate python object within a c function called via ctypes

  - by gwk

  My embedded Python 3.3 program segfaults when I instantiate python objects from a c function called by ctypes. After setting up the interpreter, I can successfully instantiate a python Int (as well as a custom c extension type) from c main: #import <Python/Python.h> #define LOGPY(x) \ { fprintf(stderr, "%s: ", #x); PyObject_Print((PyObject*)(x), stderr, 0); fputc('\n', stderr); } // c function to be called from python script via ctypes. void instantiate() { PyObject* instance = PyObject_CallObject((PyObject*)&PyLong_Type, NULL); LOGPY(instance); } int main(int argc, char* argv[]) { Py_Initialize(); instantiate(); // works fine // run a script that calls instantiate() via ctypes. FILE* scriptFile = fopen("emb.py", "r"); if (!scriptFile) { fprintf(stderr, "ERROR: cannot open script file\n"); return 1; } PyRun_SimpleFileEx(scriptFile, scriptPath, 1); // close on completion return 0; } I then run a python script using PyRun_SimpleFileEx. It appears to run just fine, but when it calls instantiate() via ctypes, the program segfaults inside PyObject_CallObject: import ctypes as ct dy = ct.CDLL('./emb') dy.instantiate() # segfaults lldb output: instance: 0 Process 52068 stopped * thread #1: tid = 0x1c03, 0x000000010000d3f5 Python`PyObject_Call + 69, stop reason = EXC_BAD_ACCESS (code=1, address=0x18) frame #0: 0x000000010000d3f5 Python`PyObject_Call + 69 Python`PyObject_Call + 69: -> 0x10000d3f5: movl 24(%rax), %edx 0x10000d3f8: incl %edx 0x10000d3fa: movl %edx, 24(%rax) 0x10000d3fd: leaq 2069148(%rip), %rax ; _Py_CheckRecursionLimit (lldb) bt * thread #1: tid = 0x1c03, 0x000000010000d3f5 Python`PyObject_Call + 69, stop reason = EXC_BAD_ACCESS (code=1, address=0x18) frame #0: 0x000000010000d3f5 Python`PyObject_Call + 69 frame #1: 0x00000001000d5197 Python`PyEval_CallObjectWithKeywords + 87 frame #2: 0x0000000201100d8e emb`instantiate + 30 at emb.c:9 Why does the call to instantiate() fail from ctypes only? The function only crashes when it calls into the python lib, so perhaps some interpreter state is getting munged by the ctypes FFI call?

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• WordPress contact form email as PDF

  - by lock

  I am using the below code for my WordPress site which is emailing all the form details as an HTML text but I need the details to be written into a PDF first and then have to email the PDF as an attachment. How can I achieve this? This is not a PHP code to use PHP's writePDF modules. So, any idea or any code to implement this? <div style="padding-left: 100px;"> [raw] [contact-form subject="Best Aussie Broker" to="[email protected]"] <div id="main34" style="border: 1px solid black; border-radius: 15px; width: 720px; padding: 15px;"> &nbsp; <h2><span style="color: #ff6600;">Express Application</span></h2> &nbsp; [contact-field label="First Name" type="name" required="true" /] [contact-field label="Last Name" type="text" /] [contact-field label="Email" type="email" required="true" /] [contact-field label="Purpose of Finance?" type="select" options="Home Loan,Refinance,Investment Loan,Debt Consolidation,Other" /] [contact-field label="Your deposit amount" type="text" /] [contact-field label="Amount you need to borrow?" type="text" /] [contact-field label="Brief description of the purpose for finance" type="textarea" required="true" /] <div><label></label> <input class="radio" type="radio" name="19" value="Single Application" onchange="showsingle();" /> <label class="radio">Single Application</label> <div class="clear-form"></div> <input class="radio" type="radio" name="19" value="Joint Application" onchange="showjoint();" /> <label class="radio">Joint Application</label> <div class="clear-form"></div> [contact-field label="Privacy Act" type="checkbox" required="true" /] I have read the Privacy Act 1988 (as Amended) and understand that by selecting the submit button I/we Authorize Best Aussie Broker to act on my/our behalf and manage personal information in relation to this application.<br> <a href="http://googleplex.com.au/pdf.pdf"><img src="http://googleplex.com.au/pdf.png" alt="" /> </a> </div> </div> <div id="single" style="display: none; width: 720px; border: 1px solid black; border-radius: 15px; padding: 15px; margin-top: 10px;"> <div style="padding-top: 10px; width: 720px; text-align: left;"> <h4><span style="color: #ff6600;">Last step then we will get all listed Australian vendors to fight it out for your best deal</span></h4> </div> <div> <label class="select" for="19-date-of-birth">Date of Birth</label> [contact-field label="Day" type="select" options="1,2,3,4,5,6,7,8,9,10,11,12,13,14,15,16,17,18,19,20,21,22,23,24,25,26,27,28,29,30,31" /] [contact-field label="Month" type="select" options="January,February,March,April,May,June,July,August,September,October,November,December" /] [contact-field label="Year" type="select" options="2000,1999,1998,1997,1996,1995,1994,1993,1992,1991,1990,1989,1988,1987,1986,1985,1984,1983,1982,1981,1980,1979,1978,197,1976,1975,1974,1973,1972,1971,1970,1969,1968,1967,1966,1965,1964,1963,1962,1961,1960,1959,1958,1957,1956,1955,1954,1953,1952,1951,1950,1949,1948,1947,1946,1945,1944,1943,1942,1941,1940,1939,1938,1937,1936,1935,1934,1933,1932,1931,1930,1929,1928,1927,1926,1925,1924,1923,1922,1921,1920, 1919,1918,1917,1916,1915,1914,1913,1912,1911,1910,1909" /] </div> [contact-field label="Address" type="text" /] [contact-field label="Suburb" type="text" /] [contact-field label="Postcode" type="text" /] <div> [contact-field label="State" type="select" options="VIC,NSW,QLD,SA,WA,TAS,NZ,Other" /] </div> [contact-field label="Best Contact" type="radio" options="Landline,Mobile" /] [contact-field label="Phone Number" type="text" /] [contact-field label="Marital Status" type="select" options="Married,Single,Other" /] [contact-field label="Residential Status" type="select" options="Renting, Home Owned, Home Mortgage, Board, Other" /] [contact-field label="Children/Dependents" type="select" options="0,1,2,3,4,5,6" /] <div></div> [contact-field label="Gross Yearly Income" type="text" /] [contact-field label="Current Employer" type="text" /] <div> <label class="select" for="19-year-of-empl">Time at this employer</label> [contact-field label="Year" type="select" options="0,1,2,3,4,5,6,7,8,9,10,More" /] [contact-field label="Month" type="select" options="0,1,2,3,4,5,6,7,8,9,10,11,12" /] </div> <div style="padding-right: 15px;"></div> </div> <div id="joint" style="display: none; width: 720px; border: 1px solid black; border-radius: 15px; padding: 15px; margin-top: 10px;"> <div style="padding-top: 10px; width: 720px; text-align: left;"> <h4><span style="color: #ff6600;">Last step then we will get all listed Australian vendors to fight it out for your best deal</span></h4> </div> <div style="float: left; width: 320px;"> <div> <label class="select" for="19-date-of-birth1">Date of Birth</label> [contact-field label="Day" type="select" options="1,2,3,4,5,6,7,8,9,10,11,12,13,14,15,16,17,18,19,20,21,22,23,24,25,26,27,28,29,30,31" /] [contact-field label="Month" type="select" options="January,February,March,April,May,June,July,August,September,October,November,December" /] [contact-field label="Year" type="select" options="2000,1999,1998,1997,1996,1995,1994,1993,1992,1991,1990,1989,1988,1987,1986,1985,1984,1983,1982,1981,1980,1979,1978,197,1976,1975,1974,1973,1972,1971,1970,1969,1968,1967,1966,1965,1964,1963,1962,1961,1960,1959,1958,1957,1956,1955,1954,1953,1952,1951,1950,1949,1948,1947,1946,1945,1944,1943,1942,1941,1940,1939,1938,1937,1936,1935,1934,1933,1932,1931,1930,1929,1928,1927,1926,1925,1924,1923,1922,1921,1920, 1919,1918,1917,1916,1915,1914,1913,1912,1911,1910,1909" /] </div> [contact-field label="Address" type="text" /] [contact-field label="Suburb" type="text" /] [contact-field label="Postcode" type="text" /] <div> [contact-field label="State" type="select" options="VIC,NSW,QLD,SA,WA,TAS,NZ,Other" /] </div> [contact-field label="Best Contact" type="radio" options="Landline,Mobile" /] [contact-field label="Phone Number" type="text" /] <div></div> <div></div> [contact-field label="Marital Status" type="select" options="Married,Single,Other" /] [contact-field label="Residential Status" type="select" options="Renting, Home Owned, Home Mortgage, Board, Other" /] [contact-field label="Children/Dependents" type="select" options="0,1,2,3,4,5,6" /] <div></div> <div><label class="text" for="netincome">Net Income</label> <input id="netincome" type="text" name="netincome" /> <select id="netincome-dropdown" name="netincome-dropdown"> <option>Monthly</option> <option>Yearly</option> </select></div> [contact-field label="Current Employer" type="text" /] <div> <label class="select" for="19-year-of-empl2">Time at this employer</label> [contact-field label="Year" type="select" options="0,1,2,3,4,5,6,7,8,9,10,More" /] [contact-field label="Month" type="select" options="0,1,2,3,4,5,6,7,8,9,10,11,12" /] </div> </div> <div style="float: right; width: 320px; padding-right: 50px;"> <div> <label class="select" for="19-date-of-birth3">Date of Birth</label> [contact-field label="Day" type="select" options="1,2,3,4,5,6,7,8,9,10,11,12,13,14,15,16,17,18,19,20,21,22,23,24,25,26,27,28,29,30,31" /] [contact-field label="Month" type="select" options="January,February,March,April,May,June,July,August,September,October,November,December" /] [contact-field label="Year" type="select" options="2000,1999,1998,1997,1996,1995,1994,1993,1992,1991,1990,1989,1988,1987,1986,1985,1984,1983,1982,1981,1980,1979,1978,197,1976,1975,1974,1973,1972,1971,1970,1969,1968,1967,1966,1965,1964,1963,1962,1961,1960,1959,1958,1957,1956,1955,1954,1953,1952,1951,1950,1949,1948,1947,1946,1945,1944,1943,1942,1941,1940,1939,1938,1937,1936,1935,1934,1933,1932,1931,1930,1929,1928,1927,1926,1925,1924,1923,1922,1921,1920, 1919,1918,1917,1916,1915,1914,1913,1912,1911,1910,1909" /] </div> [contact-field label="Address" type="text" /] [contact-field label="Suburb" type="text" /] [contact-field label="Postcode" type="text" /] <div> [contact-field label="State" type="select" options="VIC,NSW,QLD,SA,WA,TAS,NZ,Other" /] </div> [contact-field label="Best Contact" type="radio" options="Landline,Mobile" /] [contact-field label="Phone Number" type="text" /] <div></div> <div></div> [contact-field label="Marital Status" type="select" options="Married,Single,Other" /] [contact-field label="Residential Status" type="select" options="Renting, Home Owned, Home Mortgage, Board, Other" /] [contact-field label="Children/Dependents" type="select" options="0,1,2,3,4,5,6" /] <div></div> <div><label class="text" for="netincome">Net Income</label> <input id="netincome" type="text" name="netincome" /> <select id="netincome-dropdown" name="netincome-dropdown"> <option>Monthly</option> <option>Yearly</option> </select></div> [contact-field label="Current Employer" type="text" /] <div> <label class="select" for="19-year-of-empl">Time at this employer</label> [contact-field label="Year" type="select" options="0,1,2,3,4,5,6,7,8,9,10,More" /] [contact-field label="Month" type="select" options="0,1,2,3,4,5,6,7,8,9,10,11,12" /] </div> </div> <div style="clear: both;"></div> <div></div> </div> &nbsp; [/contact-form][/raw] </div>

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• WMI Query Script as a Job

  - by Kenneth

  I have two scripts. One calls the other with a list of servers as parameters. The second query is designed to execute a WMI query. When I run it manually, it does this perfectly. When I try to run it as a job it hangs forever and I have to remove it. For the sake of space here is the relevant part of the calling script: ProcessServers.ps1 Start-Job -FilePath .\GetServerDetailsLight.ps1 -ArgumentList $sqlsrv,$destdb,$server,$instance GetServerDetailsLight.ps1 param($sqlsrv,$destdb,$server,$instance) $password = get-content C:\SQLPS\auth.txt | convertto-securestring $credentials = new-object -typename System.Management.Automation.PSCredential -argumentlist "DOMAIN\MYUSER",$password [System.Reflection.Assembly]::LoadWithPartialName('Microsoft.SqlServer.SMO') $box_id = 0; if ($sqlsrv.length -eq 0) { write-output "No data passed" break } function getinfo { param( [string]$svr, [string]$inst ) "Entered GetInfo with: $svr,$inst" $cs = get-wmiobject win32_operatingsystem -computername $svr -credential $credentials -authentication 6 -Verbose -Debug | select Name, Model, Manufacturer, Description, DNSHostName, Domain, DomainRole, PartOfDomain, NumberOfProcessors, SystemType, TotalPhysicalMemory, UserName, Workgroup write-output "WMI Results: $cs" } getinfo $server $instance write-output "Complete" Executed as a job it will show as 'running' forever: PS C:\sqlps> Start-Job -FilePath .\GetServerDetailsLight.ps1 -ArgumentList DBSERVER,LOGDB,SERVER01,SERVER01 Id Name State HasMoreData Location Command -- ---- ----- ----------- -------- ------- 21 Job21 Running True localhost param($sqlsrv,$destdb,... GAC Version Location --- ------- -------- True v2.0.50727 C:\WINDOWS\assembly\GAC_MSIL\Microsoft.SqlServer.Smo\10.0.0.0__89845dcd8080cc91\Microsoft.SqlServer.Smo.dll getinfo MSDCHR01 MSDCHR01 Entered GetInfo with: SERVER01,SERVER01 The last output I ever get is the 'Entered GetInfo with: SERVER01,SERVER01'. If I run it manually like so: PS C:\sqlps> .\GetServerDetailsLight.ps1 DBSERVER LOGDB SERVER01 SERVER01 The WMI query executes just as expected. I am trying to determine why this is, or at least a useful way to trap errors from within jobs. Thanks!

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• Linq 2 SQL Store inherited classes - not mapped to tables in the database

  - by user348672

  Hi. I'm trying to introduce the Linq2SQL technique into the project and have encountered the following issue: I've created ORM classes based on the Northwind database. In some other application I create several classes derived from the Linq2SQL classes. I'm able to add such a class to EntitySet but the application fails to submit changes. Is there any way around this? Sample code(MyClass is derived from the Order): DataClasses1DataContext northwind = new DataClasses1DataContext(); Product chai = northwind.Products.Single(p => p.ProductName == "Chai"); Product tofu = northwind.Products.Single(p => p.ProductName == "Tofu"); Order myOrder = new Order(); myOrder.OrderDate = DateTime.Now; myOrder.RequiredDate = DateTime.Now.AddDays(1); myOrder.Freight = 34; Order_Detail myItem1 = new Order_Detail(); myItem1.Product = chai; myItem1.Quantity = 12345; Order_Detail myItem2 = new Order_Detail(); myItem2.Product = tofu; myItem2.Quantity = 3; myOrder.Order_Details.Add(myItem1); myOrder.Order_Details.Add(myItem2); Customer myCustomer = northwind.Customers.Single(c => c.CompanyName == "B's Beverages"); MyClass newOrder = new MyClass(); newOrder.OrderDate = DateTime.Now; newOrder.RequiredDate = DateTime.Now.AddDays(31); newOrder.Freight = 35; Order_Detail myItem3 = new Order_Detail(); myItem3.Product = tofu; myItem3.Quantity = 3; newOrder.Order_Details.Add(myItem3); myCustomer.Orders.Add(myOrder); myCustomer.Orders.Add(newOrder); As I said I'm able to add the newOrder object but unable to submit into the database.

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• C#: Easy access to the member of a singleton ICollection<> ?

  - by Rosarch

  I have an ICollection that I know will only ever have one member. Currently, I loop through it, knowing the loop will only ever run once, to grab the value. Is there a cleaner way to do this? I could alter the persistentState object to return single values, but that would complicate the rest of the interface. It's grabbing data from XML, and for the most part ICollections are appropriate. // worldMapLinks ensured to be a singleton ICollection<IDictionary<string, string>> worldMapLinks = persistentState.GetAllOfType("worldMapLink"); string levelName = ""; //worldMapLinks.GetEnumerator().Current['filePath']; // this loop will only run once foreach (IDictionary<string, string> dict in worldMapLinks) // hacky hack hack hack { levelName = dict["filePath"]; } // proceed with levelName loadLevel(levelName); Here is another example of the same issue: // meta will be a singleton ICollection<IDictionary<string, string>> meta = persistentState.GetAllOfType("meta"); foreach (IDictionary<string, string> dict in meta) // this loop should only run once. HACKS. { currentLevelName = dict["name"]; currentLevelCaption = dict["teaserCaption"]; } Yet another example: private Vector2 startPositionOfKV(ICollection<IDictionary<string, string>> dicts) { Vector2 result = new Vector2(); foreach (IDictionary<string, string> dict in dicts) // this loop will only ever run once { result.X = Single.Parse(dict["x"]); result.Y = Single.Parse(dict["y"]); } return result; }

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• Horizontally align rows in multiple tables using web user control

  - by goku_da_master

  I need to align rows in different tables that are layed out horizontally. I'd prefer to put the html code in a single web user control so I can create as many instances of that control as I want and lay them out horizontally. The problem is, the text in the rows needs to wrap. So some rows may expand vertically and some may not (see the example below). When that happens, the rows in the other tables aren't aligned horizontally. I know I can accomplish all this by using a single table, but that would mean I'd have to duplicate the name, address and phone html code instead of dynamically creating new instances of my user control (in reality there are many more fields than this, but I'm keeping it simple). Is there any way to do this whether with div's, tables or something else? Here's the problem: Mary Jane's address field expands 2 lines, causing her phone field to not align properly with John's and Bob's. Name: John Doe Name: Mary Jane Name: Bob Smith Address: 123 broadway Address: Some really long address Address: Short address Phone: 123-456 that takes up multiple lines Phone: 111-2222 Phone: 456-789 I'm not restricted in any way how to do this (other than using asp.net), but I'd prefer to use a single web control that I instantiate X times at design time (in this example, it's 3 times). I'm using VS2008, and .Net 3.5

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• Proper Usage of SqlConnection in .NET

  - by Jojo

  Hi guys, I just want an opinion on the proper usage or a proper design with regards to using SqlConnection object. Which of the 2 below is the best use: A data provider class whose methods (each of them) contain SqlConnection object (and disposed when done). Like: IList<Employee> GetAllEmployees() { using (SqlConnection connection = new SqlConnection(this.connectionString)) { // Code goes here... } } Employee GetEmployee(int id) { using (SqlConnection connection = new SqlConnection(this.connectionString)) { // Code goes here... } } or SqlConnection connection; // initialized in constructor IList<Employee> GetAllEmployees() { this.TryOpenConnection(); // tries to open member SqlConnection instance // Code goes here... this.CloseConnection(); // return } Employee GetEmployee(int id) { this.TryOpenConnection(); // tries to open member SqlConnection instance // Code goes here... this.CloseConnection(); // return } Or is there a better approach than this? I have a focused web crawler type of application and this application will crawl 50 or more websites simultaneously (multithreaded) with each website contained in a crawler object and each crawler object has an instance of a data provider class (above). Please advise. Thanks.

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• Splitting build cross the network?

  - by Dandikas

  Is there a known solution for splitting build process cross the network machines? Use case: We are an average software development company. We own around 50 development workstations (Quad Core 2.66Ghz, 4 GB ram, 200 GB raid). No need to tell that at any single moment not every machine is loaded to the max. There are 5 to 15 projects running simultaneously at any single moment. Obviously all of them are continuously build on server, than deployed to proper environment. Single project build is taking from 3 to 15 minutes. The problem: Whenever we build 5 projects in a row the last project is going to be ready after around 25 - 50 minutes. Building in parallel does not solve the problem (build is only a part of the game, than you need to deploy, run tests etc.) YES the correct solution is to add another build server, but "That involves buying new Expensive hardware, and we already spent a lot!". Yea, right(damn them)! Anyway. What about splitting build among developers workstation? Lets say whenever we need to build project "A" we check 5 workstations and start build on all that are not overloaded. The build can be canceled by a developer if he really needs all the power of his machine as long as there is at least 1 machine that is still building. After build is finished deployment can be performed to a proper environment (hosted on some server, not on workstation :) ). The bigger the company the more this makes sense to me. Anyone tried something like this? Are there any good practices? Any helpful software? (90% of the projects are .net C#)

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• Binding type variables that only occur in assertions

  - by Giuseppe Maggiore

  Hi! I find it extremely difficult to describe my problem, so here goes nothing: I have a bunch of assertions on the type of a function. These assertions rely on a type variable that is not used for any parameter of the function, but is only used for internal bindings. Whenever I use this function it does not compile because, of course, the compiler has no information from which to guess what type to bind my type variable. Here is the code: {-# LANGUAGE MultiParamTypeClasses, FunctionalDependencies, FlexibleInstances, UndecidableInstances, FlexibleContexts, EmptyDataDecls, ScopedTypeVariables, TypeOperators, TypeSynonymInstances #-} class C a a' where convert :: a -> a' class F a b where apply :: a -> b class S s a where select :: s -> a data CInt = CInt Int instance S (Int,String) Int where select (i,_) = i instance F Int CInt where apply = CInt f :: forall s a b . (S s a, F a b) => s -> b f s = let v = select s :: a y = apply v :: b in y x :: Int x = f (10,"Pippo") And here is the generated error: FunctorsProblems.hs:21:4: No instances for (F a Int, S (t, [Char]) a) arising from a use of `f' at FunctorsProblems.hs:21:4-17 Possible fix: add an instance declaration for (F a Int, S (t, [Char]) a) In the expression: f (10, "Pippo") In the definition of `x': x = f (10, "Pippo") Failed, modules loaded: none. Prelude>

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