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  • C# TcpClient, getting back the entire response from a telnet device

    - by Dan Bailiff
    I'm writing a configuration tool for a device that can communicate via telnet. The tool sends a command via TcpClient.GetStream().Write(...), and then checks for the device response via TcpClient.GetStream().ReadByte(). This works fine in unit tests or when I'm stepping through code slowly. If I run the config tool such that it performs multiple commands consecutively, then the behavior of the read is inconsistent. By inconsistent I mean sometimes the data is missing, incomplete or partially garbled. So even though the device performed the operation and responded, my code to check for the response was unreliable. I "fixed" this problem by adding a Thread.Sleep to make sure the read method waits long enough for the device to complete its job and send back the whole response (in this case 1.5 seconds was a safe amount). I feel like this is wrong, blocking everything for a fixed time, and I wonder if there is a better way to get the read method to wait only long enough to get the whole response from the device. private string Read() { if (!tcpClient.Connected) throw (new Exception("Read() failed: Telnet connection not available.")); StringBuilder sb = new StringBuilder(); do { ParseTelnet(ref sb); System.Threading.Thread.Sleep(1500); } while (tcpClient.Available > 0); return sb.ToString(); } private void ParseTelnet(ref StringBuilder sb) { while (tcpClient.Available > 0) { int input = tcpClient.GetStream().ReadByte(); switch (input) { // parse the input // ... do other things in special cases default: sb.Append((char)input); break; } } }

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  • return an ArrayList method

    - by Bopeng Liu
    This is a drive method for two other classes. which i posted here http://codereview.stackexchange.com/questions/33148/book-program-with-arraylist I need some help for the private static ArrayList getAuthors(String authors) method. I am kind a beginner. so please help me finish this drive method. or give me some directions. Instruction some of the elements of the allAuthors array contain asterisks “*” between two authors names. The getAuthors method uses this asterisk as a delimiter between names to store them separately in the returned ArrayList of Strings. import java.util.ArrayList; public class LibraryDrive { public static void main(String[] args) { String[] titles = { "The Hobbit", "Acer Dumpling", "A Christmas Carol", "Marley and Me", "Building Java Programs", "Java, How to Program" }; String[] allAuthors = { "Tolkien, J.R.", "Doofus, Robert", "Dickens, Charles", "Remember, SomeoneIdont", "Reges, Stuart*Stepp, Marty", "Deitel, Paul*Deitel, Harvery" }; ArrayList<String> authors = new ArrayList<String>(); ArrayList<Book> books = new ArrayList<Book>(); for (int i = 0; i < titles.length; i++) { authors = getAuthors(allAuthors[i]); Book b = new Book(titles[i], authors); books.add(b); authors.remove(0); } Library lib = new Library(books); System.out.println(lib); lib.sort(); System.out.println(lib); } private static ArrayList<String> getAuthors(String authors) { ArrayList books = new ArrayList<String>(); // need help here. return books; } }

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  • Web API Getting Http 500 error : Issue Solved See Below

    - by Joe Grasso
    Here is my MVC Controller and everything is fine: private UnitOfWork UOW; public InventoryController() { UOW = new UnitOfWork(); } // GET: /Inventory/ public ActionResult Index() { var products = UOW.ProductRepository.GetAll().ToList(); return View(products); } Same method call in API Controller gives me an Http 500 Error: private UnitOfWork _unitOfWork; public TestController() { _unitOfWork = new UnitOfWork(); } public IEnumerable<Product> Get() { var products = _unitOfWork.ProductRepository.GetAll().ToList(); return products; } Debugging shows that indeed there is data being returned in both controllers' UOW calls. I then added a customer configuration in Global: public static void CustomizeConfig(HttpConfiguration config) { config.Formatters.Remove(config.Formatters.XmlFormatter); var json = config.Formatters.JsonFormatter; json.SerializerSettings.ContractResolver = new CamelCasePropertyNamesContractResolver(); } I am still receiving an Http 500 in API Controller ONLY and at a loss as to why. Any ideas? UPDATE: It appears using lazy loading caused the problem. When I set the associated properties to NON-VIRTUAL the Test API provided the necessary JSON string. However, whereas before I had the Vendor class included, I only have VendorId. I really wanted to included the associated classes. Any ideas? I know there are alot of smart people out there. Anyone?

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  • @WebServices as @Stateless session bean in ejb jar

    - by kislo_metal
    Hi! Scenario: Creating some web service as @Stateless bean, package it as ejb jar. Result - can`t access to wsdl file. Goal: I want to use @WebServices as @Stateless session using ejb jar packaging with accessible wsdl file form web. Web service: @Stateless @WebService(serviceName = "ws.isp.SecurityService", wsdlLocation = "META-INF/wsdl/SecurityService.wsdl") public class SecurityService{ @EJB private Kerberos factory; @EJB private UsersServiceBean uService; public SecurityService() { } @WebMethod @WebResult(name = "SimpleResponse") public SimpleResponse LogOut( @WebParam(name = "sessionUUID", targetNamespace = "https://secure.co.ua/ws/") String sessionUUID ) { SimpleResponse resp = new SimpleResponse(); try{ factory.removeSession(sessionUUID); resp.setError(WSErrorCodes.SUCCESS); }catch (Exception e){ e.printStackTrace(); resp.setError(WSErrorCodes.UNRELOSVED_ERROR); } return resp; } @WebMethod public MySession logIn( @WebParam(name = "username", targetNamespace = "https://secure.co.ua/ws/") String username, @WebParam(name = "password", targetNamespace = "https://secure.co.ua/ws/") String password){ MySession result = new MySession(); try { UserSession us = factory.creatSession(uService.getUser(username, password).getId()); result.setSessionID(us.getSessionUUID().toString()); result.setError(WSErrorCodes.SUCCESS); } catch (NullPointerException e){ e.printStackTrace(); result.setError(WSErrorCodes.UNRELOSVED_USER); } catch (Exception e){ e.printStackTrace(); result.setError(WSErrorCodes.UNRELOSVED_ERROR); } return result; } } In this case I getting Invalid wsdl request http://192.168.44.48:8181/ws.isp.SecurityService/SecurityService when I try to access to wsdl and if do not use description of wsdlLocation I getting blank page. Web service as it self working good. Q1: what is the rule of describing wsdl file location for web services as stateless in ejb jar. Q2: is it possible to generate wsdl file during maven packaging ? Q3: how to generate wsdl file for web service where we have such annotation as @Stateless and @EJB (currently I can generate it only by commenting those annotations) environment: mave 2, ejb 3.1, glassfish v3, jax-ws 2.x Thank you!

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  • In which scenario it is useful to use Disassembly on python?

    - by systempuntoout
    The dis module can be effectively used to disassemble Python methods, functions and classes into low-level interpreter instructions. I know that dis information can be used for: 1. Find race condition in programs that use threads 2. Find possible optimizations From your experience, do you know any other scenarios where Disassembly Python feature could be useful?

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  • CLR 4.0 inlining policy? (maybe bug with MethodImplOptions.NoInlining)

    - by ControlFlow
    I've testing some new CLR 4.0 behavior in method inlining (cross-assembly inlining) and found some strage results: Assembly ClassLib.dll: using System.Diagnostics; using System; using System.Reflection; using System.Security; using System.Runtime.CompilerServices; namespace ClassLib { public static class A { static readonly MethodInfo GetExecuting = typeof(Assembly).GetMethod("GetExecutingAssembly"); public static Assembly Foo(out StackTrace stack) // 13 bytes { // explicit call to GetExecutingAssembly() stack = new StackTrace(); return Assembly.GetExecutingAssembly(); } public static Assembly Bar(out StackTrace stack) // 25 bytes { // reflection call to GetExecutingAssembly() stack = new StackTrace(); return (Assembly) GetExecuting.Invoke(null, null); } public static Assembly Baz(out StackTrace stack) // 9 bytes { stack = new StackTrace(); return null; } public static Assembly Bob(out StackTrace stack) // 13 bytes { // call of non-inlinable method! return SomeSecurityCriticalMethod(out stack); } [SecurityCritical, MethodImpl(MethodImplOptions.NoInlining)] static Assembly SomeSecurityCriticalMethod(out StackTrace stack) { stack = new StackTrace(); return Assembly.GetExecutingAssembly(); } } } Assembly ConsoleApp.exe using System; using ClassLib; using System.Diagnostics; class Program { static void Main() { Console.WriteLine("runtime: {0}", Environment.Version); StackTrace stack; Console.WriteLine("Foo: {0}\n{1}", A.Foo(out stack), stack); Console.WriteLine("Bar: {0}\n{1}", A.Bar(out stack), stack); Console.WriteLine("Baz: {0}\n{1}", A.Baz(out stack), stack); Console.WriteLine("Bob: {0}\n{1}", A.Bob(out stack), stack); } } Results: runtime: 4.0.30128.1 Foo: ClassLib, Version=1.0.0.0, Culture=neutral, PublicKeyToken=null at ClassLib.A.Foo(StackTrace& stack) at Program.Main() Bar: ClassLib, Version=1.0.0.0, Culture=neutral, PublicKeyToken=null at ClassLib.A.Bar(StackTrace& stack) at Program.Main() Baz: at Program.Main() Bob: ClassLib, Version=1.0.0.0, Culture=neutral, PublicKeyToken=null at Program.Main() So questions are: Why JIT does not inlined Foo and Bar calls as Baz does? They are lower than 32 bytes of IL and are good candidates for inlining. Why JIT inlined call of Bob and inner call of SomeSecurityCriticalMethod that is marked with the [MethodImpl(MethodImplOptions.NoInlining)] attribute? Why GetExecutingAssembly returns a valid assembly when is called by inlined Baz and SomeSecurityCriticalMethod methods? I've expect that it performs the stack walk to detect the executing assembly, but stack will contains only Program.Main() call and no methods of ClassLib assenbly, to ConsoleApp should be returned.

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  • Dynamically change ViewPagerIndicator titles

    - by msal
    My current project uses some ListFragments to show rows of data. The rows get updated dynamically every some seconds. The amount of rows varies with every update and in every ListFragment. I would like to show the amount of rows to the user, and think that the perfect place for that would be next to the Fragment's title in the ViewPagerIndicator. I provided a sample image for better comprehension: Sadly I am pretty clueless how to achieve this. I tried the following: public class PagerAdapter extends FragmentPagerAdapter { private int numOne = 0; private int numTwo = 0; // ... @Override public CharSequence getPageTitle(int position) { switch (position) { case 0: return "List 1 (" + numOne + ")"; case 1: return "List 2 (" + numTwo + ")"; default: return ""; } public void setNumOne(int num) { this.numOne = num; } public void setNumTwo(int num) { this.numTwo = num; } } When I now call the setNumXXX() method, nothing happens, until I move between fragments, what seems to trigger the getPageTitle() to fire. My question is: How can I force an update of the title(s), everytime when the num value changes?

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  • Applying policy based design question

    - by Arthur
    I've not read the Modern C++ Design book but have found the idea of behavior injection through templates interesting. I am now trying to apply it myself. I have a class that has a logger that I thought could be injected as a policy. The logger has a log() method which takes an std::string or std::wstring depending on its policy: // basic_logger.hpp template<class String> class basic_logger { public: typedef String string_type; void log(const string_type & s) { ... } }; typedef basic_logger<std::string> logger; typedef basic_logger<std::wstring> wlogger; // reader.hpp template<class Logger = logger> class reader { public: typedef Logger logger_type; void read() { _logger.log("Reading..."); } private: logger_type _logger; }; Now the questing is, should the reader take a Logger as an argument, like above, or should it take a String and then instantiate a basic_logger as an instance variable? Like so: template<class String> class reader { public: typedef String string_type; typedef basic_logger<string_type> logger_type; // ... private: logger_type _logger; }; What is the right way to go?

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  • main vs initialize in Ruby

    - by Dave
    Okay, so I've looked through a couple of my ruby books and done some googling to no avail. What is the difference between main and initialize in Ruby? I've seen code that uses class Blahblah def main some logic here end #more methods... end and then calls it using Blahblah.new. Isn't new reserved only for initialize? if not, then what's the difference between the two?

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  • serialport error

    - by I__
    i have the following code: using System; using System.Collections.Generic; using System.ComponentModel; using System.Data; using System.Drawing; using System.Linq; using System.Text; using System.Windows.Forms; using System.Threading; namespace WindowsFormsApplication1 { public partial class Form1 : Form { public Form1() { InitializeComponent(); } public class ThreadWork { public static void DoWork() { serialPort1.Open(); serialPort1.Write("AT+CMGF=1\r\n"); //Thread.Sleep(500); serialPort1.Write("AT+CNMI=2,2\r\n"); //Thread.Sleep(500); serialPort1.Write("AT+CSCA=\"+4790002100\"\r\n"); //Thread.Sleep(500); serialPort1.DataReceived += serialPort1_DataReceived_1; } } private void Form1_Load(object sender, EventArgs e) { ThreadStart myThreadDelegate = new ThreadStart(ThreadWork.DoWork); Thread myThread = new Thread(myThreadDelegate); myThread.Start(); } private void serialPort1_DataReceived_1(object sender, System.IO.Ports.SerialDataReceivedEventArgs e) { string response = serialPort1.ReadLine(); this.BeginInvoke(new MethodInvoker(() => textBox1.AppendText(response + "\r\n"))); } } } and for all the serialport1 lines i am getting this error: Error 1 An object reference is required for the non-static field, method, or property 'WindowsFormsApplication1.Form1.serialPort1' C:\Users\alexluvsdanielle\AppData\Local\Temporary Projects\WindowsFormsApplication1\Form1.cs 23 17 WindowsFormsApplication1 what am i doing wrong?

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  • Sending email via GMail in .NET

    - by VP
    I am getting the following error when I try to send an email in my C# program. I am using Visual Studio 2008 on windows 7. I would paste my code first and then the error: class email_log_files { private string login_username = "my_gmail_id"; private string login_password = "my_gmail_password"; public void send_email() { string src_address = "[email protected]"; string dest_address = "[email protected]"; try { MailMessage email_msg = new MailMessage(); SmtpClient email_client = new SmtpClient(); email_msg.From = new MailAddress(src_address); email_msg.Sender = new MailAddress(src_address); email_msg.ReplyTo = new MailAddress(src_address); email_msg.To.Add(dest_address); email_msg.Subject = "Test"; email_msg.Body = "Body of the message"; NetworkCredential credentials = new NetworkCredential(login_username, login_password); email_client.Credentials = credentials; email_client.Host = "smtp.gmail.com"; email_client.Port = 465; email_client.EnableSsl = true; email_client.Send(email_msg); Console.WriteLine("Message Sent Successfully!!"); Console.ReadLine(); } } } And the error message is as follows: The operation has timed out. Why is it always timing out? I am sure that I have the correct smtp server address and port number for gmail as I have configured my outlook with the same. Any help or ideas?

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  • Assign delegate event handler from dynamically added child control

    - by mickyjtwin
    I have a control that handles commenting. In this control, I have set a delegate event handler for sending an email. I then have various types of controls, e.g. blog, articles etc, each of which may or may not have the commenting control added (which is done dynamically with me not knowing the id's), i.e. the commenting control is added outside this control. Each of these controls handles it's emailing differently(hence the event). What I'm trying to determine, is how to assign the event in the parent control. At the moment, I'm having to recursively search through all the controls on the page until I find the comment control, and set it that way. Example below explains: COMMENTING CONTROL public delegate void Commenting_OnSendEmail(); public partial class Commenting : UserControl { public Commenting_OnSendEmail OnComment_SendEmail(); private void Page_Load(object sender, EventArgs e) { if(OnComment_SendEmail != null) { OnComment_SendEmail(); } } } PARENT CONTROL public partial class Blog : UserControl { private void Page_Load(object sender, EventArgs e) { Commenting comControl = (Commenting)this.FindControl<Commenting>(this); if(comControl != null) { comCtrol.OnComment_SendEmail += new Commenting_OnSendMail(Blog_Comment_OnSendEmail); } } } Is there an easier way?

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  • How do I display children in succession, as3

    - by VideoDnd
    How do I display children in succession? By succession I mean 1,2,3,4, etc. Perhapse incrementing with a loop or using a timer is what I'm after. Add, remove, appear, or disappear children, could all work. I want a simple way to display 1 child every second until I reach 10. METHODS TRYED addChild and removeChild visible !visible for loop

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  • Problem in implementing IAlertUpdateHandler interface

    - by TheVillageIdiot
    I've implemented IAlertUpdateHandler interface in a class and used it for handling creation and updating of alerts. The code is fired but it goes into endless loop by calling itself again and again. Actually I want to suppress email notification so I'm calling a.Update(false); but this again calls PreUpdate or PostUpdate method and there is StackOverFlowException :( I've tried returning true/false from both the methods but nothing is helping.

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  • is it possible to display video information from an rtsp stream in an android app UI

    - by Joseph Cheung
    I have managed to get a working video player that can stream rtsp links, however im not sure how to display the videos current time position in the UI, i have used the getDuration and getCurrentPosition calls, stored this information in a string and tried to display it in the UI but it doesnt seem to work in main.xml: TextView android:id="@+id/player" android:layout_width="wrap_content" android:layout_height="wrap_content" android:layout_margin="1px" android:text="@string/cpos" / in strings.xml: string name="cpos""" /string in Player.java private void playVideo(String url) { try { media.setEnabled(false); if (player == null) { player = new MediaPlayer(); player.setScreenOnWhilePlaying(true); } else { player.stop(); player.reset(); } player.setDataSource(url); player.getCurrentPosition(); player.setDisplay(holder); player.setAudioStreamType(AudioManager.STREAM_MUSIC); player.setOnPreparedListener(this); player.prepareAsync(); player.setOnBufferingUpdateListener(this); player.setOnCompletionListener(this); } catch (Throwable t) { Log.e(TAG, "Exception in media prep", t); goBlooey(t); try { try { player.prepare(); } catch (IOException e) { // TODO Auto-generated catch block e.printStackTrace(); } Log.v(TAG, "Duration: === " + player.getDuration()); } catch (IllegalStateException e) { // TODO Auto-generated catch block e.printStackTrace(); } } } private Runnable onEverySecond = new Runnable() { public void run() { if (lastActionTime 0 && SystemClock.elapsedRealtime() - lastActionTime 3000) { clearPanels(false); } if (player != null) { timeline.setProgress(player.getCurrentPosition()); //stores getCurrentPosition as a string cpos = String.valueOf(player.getCurrentPosition()); System.out.print(cpos); } if (player != null) { timeline.setProgress(player.getDuration()); //stores getDuration as a string cdur = String.valueOf(player.getDuration()); System.out.print(cdur); } if (!isPaused) { surface.postDelayed(onEverySecond, 1000); } } };

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  • Optimizing C# code in MVC controller

    - by cc0
    I am making a number of distinct controllers, one relating to each stored procedure in a database. These are only used to read data and making them available in JSON format for javascripts. My code so far looks like this, and I'm wondering if I have missed any opportunities to re-use code, maybe make some help classes. I have way too little experience doing OOP, so any help and suggestions here would be really appreciated. Here is my generalized code so far (tested and works); using System; using System.Configuration; using System.Web.Mvc; using System.Data; using System.Text; using System.Data.SqlClient; using Prototype.Models; namespace Prototype.Controllers { public class NameOfStoredProcedureController : Controller { char[] lastComma = { ',' }; String oldChar = "\""; String newChar = "&quot;"; StringBuilder json = new StringBuilder(); private String strCon = ConfigurationManager.ConnectionStrings["SomeConnectionString"].ConnectionString; private SqlConnection con; public StoredProcedureController() { con = new SqlConnection(strCon); } public string do_NameOfStoredProcedure(int parameter) { con.Open(); using (SqlCommand cmd = new SqlCommand("NameOfStoredProcedure", con)) { cmd.CommandType = CommandType.StoredProcedure; cmd.Parameters.AddWithValue("@parameter", parameter); using (SqlDataReader reader = cmd.ExecuteReader()) { while (reader.Read()) { json.AppendFormat("[{0},\"{1}\"],", reader["column1"], reader["column2"]); } } con.Close(); } if (json.Length.ToString().Equals("0")) { return "[]"; } else { return "[" + json.ToString().TrimEnd(lastComma) + "]"; } } //http://host.com/NameOfStoredProcedure?parameter=value public ActionResult Index(int parameter) { return new ContentResult { ContentType = "application/json", Content = do_NameOfStoredProcedure(parameter) }; } } }

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  • How to set the Windows Mobile 6 IME mode (to numbers only)

    - by Daniel Crenna
    In Windows Mobile 5 one of the following methods works to set an input to numbers only: // Managed InputModeEditor.SetInputMode(textBox, InputMode.Numeric); // Native Wrapper InputModeSupport.SHSetImeMode(textBox.Handle, InputModeSupport.SHIME_MODE.SHIME_MODE_NUMBERS); In Windows Mobile 6, neither works. How do you set the IME to "Numbers Only" in WM 6.0 / .NET CF 3.5?

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  • JCE Pro - Any good?

    - by Tom
    Hi Guys, I was wondering if anyone has had any valid experience with JCE Pro ? http://www.syntropy.se - javascript obfuscation Or any other good obfuscation methods for that reason ?

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  • Correct way of setting a custom FileInfo class to an Iterator

    - by Gordon
    I am trying to set a custom class to an Iterator through the setInfoClass method: Use this method to set a custom class which will be used when getFileInfo and getPathInfo are called. The class name passed to this method must be derived from SplFileInfo. My class is like this (simplified example): class MyFileInfo extends SplFileInfo { public $props = array( 'foo' => '1', 'bar' => '2' ); } The iterator code is this: $rit = new RecursiveIteratorIterator( new RecursiveDirectoryIterator('/some/file/path/'), RecursiveIteratorIterator::SELF_FIRST); Since RecursiveDirectoryIterator is by inheritance through DirectoryIterator also an SplFileInfo object, it provides the setInfoClass method (it's not listed in the manual, but reflection shows it's there). Thus I can do: $rit->getInnerIterator()->setInfoClass('MyFileInfo'); All good up to here, but when iterating over the directory with foreach($rit as $file) { var_dump( $file ); } I get the following weird result object(MyFileInfo)#4 (3) { ["props"]=>UNKNOWN:0 ["pathName":"SplFileInfo":private]=>string(49) "/some/file/path/someFile.txt" ["fileName":"SplFileInfo":private]=>string(25) "someFile.txt" } So while MyFileInfo is picked up, I cannot access it's properties. If I add custom methods, I can invoke them fine, but any properties are UNKNOWN. If I don't set the info class to the iterator, but to the SplFileInfo object (like shown in the example in the manual), it will give the same UNKNOWN result: foreach($rit as $file) { // $file is a SplFileInfo instance $file->setInfoClass('MyFileInfo'); var_dump( $file->getFileInfo() ); } However, it will work when I do foreach($rit as $file) { $file = new MyFileInfo($file); var_dump( $file ); } Unfortunately, the code I a want to use this in is somewhat more complicated and stacks some more iterators. Creating the MyFileInfo class like this is not an option. So, does anyone know how to get this working or why PHP behaves this weird? Thanks.

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  • Is there any way to delete an HttpOnly cookie from C# Selenium tests?

    - by BenA
    I have a set of C# Selenium tests that need to delete a cookie that has the HttpOnly flag set. Unfortunately the DefaultSelenium.GetCookie() and DefaultSelenium.DeleteCookie() commands aren't able to access the cookie, because it has that HttpOnly flag set. I've confirmed this by removing the flag by hand, and checking that subsequent calls to either of those methods are then happily able to manipulate the cookie in question. Is there any other way to do this via the Selenium .NET client driver? All ideas welcome!

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  • Implementing a robust async stream reader for a console

    - by Jon
    I recently provided an answer to this question: C# - Realtime console output redirection. As often happens, explaining stuff (here "stuff" was how I tackled a similar problem) leads you to greater understanding and/or, as is the case here, "oops" moments. I realized that my solution, as implemented, has a bug. The bug has little practical importance, but it has an extremely large importance to me as a developer: I can't rest easy knowing that my code has the potential to blow up. Squashing the bug is the purpose of this question. I apologize for the long intro, so let's get dirty. I wanted to build a class that allows me to receive input from a Stream in an event-based manner. The stream, in my scenario, is guaranteed to be a FileStream and there is also an associated StreamReader already present to leverage. The public interface of the class is this: public class MyStreamManager { public event EventHandler<ConsoleOutputReadEventArgs> StandardOutputRead; public void StartSendingEvents(); public void StopSendingEvents(); } Obviously this specific scenario has to do with a console's standard output. StartSendingEvents and StopSendingEvents do what they advertise; for the purposes of this discussion, we can assume that events are always being sent without loss of generality. The class uses these two fields internally: protected readonly StringBuilder inputAccumulator = new StringBuilder(); protected readonly byte[] buffer = new byte[256]; The functionality of the class is implemented in the methods below. To get the ball rolling: public void StartSendingEvents(); { this.stopAutomation = false; this.BeginReadAsync(); } To read data out of the Stream without blocking, and also without requiring a carriage return char, BeginRead is called: protected void BeginReadAsync() { if (!this.stopAutomation) { this.StandardOutput.BaseStream.BeginRead( this.buffer, 0, this.buffer.Length, this.ReadHappened, null); } } The challenging part: BeginRead requires using a buffer. This means that when reading from the stream, it is possible that the bytes available to read ("incoming chunk") are larger than the buffer. Since we are only handing off data from the stream to a consumer, and that consumer may well have inside knowledge about the size and/or format of these chunks, I want to call event subscribers exactly once for each chunk. Otherwise the abstraction breaks down and the subscribers have to buffer the incoming data and reconstruct the chunks themselves using said knowledge. This is much less convenient to the calling code, and detracts from the usefulness of my class. Edit: There are comments below correctly stating that since the data is coming from a stream, there is absolutely nothing that the receiver can infer about the structure of the data unless it is fully prepared to parse it. What I am trying to do here is leverage the "flush the output" "structure" that the owner of the console imparts while writing on it. I am prepared to assume (better: allow my caller to have the option to assume) that the OS will pass me the data written between two flushes of the stream in exactly one piece. To this end, if the buffer is full after EndRead, we don't send its contents to subscribers immediately but instead append them to a StringBuilder. The contents of the StringBuilder are only sent back whenever there is no more to read from the stream (thus preserving the chunks). private void ReadHappened(IAsyncResult asyncResult) { var bytesRead = this.StandardOutput.BaseStream.EndRead(asyncResult); if (bytesRead == 0) { this.OnAutomationStopped(); return; } var input = this.StandardOutput.CurrentEncoding.GetString( this.buffer, 0, bytesRead); this.inputAccumulator.Append(input); if (bytesRead < this.buffer.Length) { this.OnInputRead(); // only send back if we 're sure we got it all } this.BeginReadAsync(); // continue "looping" with BeginRead } After any read which is not enough to fill the buffer, all accumulated data is sent to the subscribers: private void OnInputRead() { var handler = this.StandardOutputRead; if (handler == null) { return; } handler(this, new ConsoleOutputReadEventArgs(this.inputAccumulator.ToString())); this.inputAccumulator.Clear(); } (I know that as long as there are no subscribers the data gets accumulated forever. This is a deliberate decision). The good This scheme works almost perfectly: Async functionality without spawning any threads Very convenient to the calling code (just subscribe to an event) Maintains the "chunkiness" of the data; this allows the calling code to use inside knowledge of the data without doing any extra work Is almost agnostic to the buffer size (it will work correctly with any size buffer irrespective of the data being read) The bad That last almost is a very big one. Consider what happens when there is an incoming chunk with length exactly equal to the size of the buffer. The chunk will be read and buffered, but the event will not be triggered. This will be followed up by a BeginRead that expects to find more data belonging to the current chunk in order to send it back all in one piece, but... there will be no more data in the stream. In fact, as long as data is put into the stream in chunks with length exactly equal to the buffer size, the data will be buffered and the event will never be triggered. This scenario may be highly unlikely to occur in practice, especially since we can pick any number for the buffer size, but the problem is there. Solution? Unfortunately, after checking the available methods on FileStream and StreamReader, I can't find anything which lets me peek into the stream while also allowing async methods to be used on it. One "solution" would be to have a thread wait on a ManualResetEvent after the "buffer filled" condition is detected. If the event is not signaled (by the async callback) in a small amount of time, then more data from the stream will not be forthcoming and the data accumulated so far should be sent to subscribers. However, this introduces the need for another thread, requires thread synchronization, and is plain inelegant. Specifying a timeout for BeginRead would also suffice (call back into my code every now and then so I can check if there's data to be sent back; most of the time there will not be anything to do, so I expect the performance hit to be negligible). But it looks like timeouts are not supported in FileStream. Since I imagine that async calls with timeouts are an option in bare Win32, another approach might be to PInvoke the hell out of the problem. But this is also undesirable as it will introduce complexity and simply be a pain to code. Is there an elegant way to get around the problem? Thanks for being patient enough to read all of this.

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  • Subclassing NSObject, can it cause problems?

    - by Sheehan Alam
    I have a very basic data class that is subclassed from NSObject. I declare a few strings, make sure they have properties (nonatomic, copy), and synthesize them. The only method I implemented was dealloc() which releases my strings. Can any memory problems arise from just this? Are there any other methods I need to implement?

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  • Rails logger messages test.log?

    - by Dave Paroulek
    Is it possible to configure rails to show logger.debug messages (from logger.debug statements inside controllers) to display inside test.log (or to the console) when running unit and functional tests? I added the following to test_helper.rb. I see messages from logger.debug statements directly inside tests but no messages from logger statements inside controller methods? def logger RAILS_DEFAULT_LOGGER end

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