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  • java I/O is blocked while reading on socket when i put off the battery from device.

    - by gunjan goyal
    hi, i m working on client socket connection. client is a GPRS hardware device. i m receiving request from this client on my serversocket and then opening multiple threads. my problem is that when device/client close the socket then my IO detects that throws an exception but when i put off the battery from the device while sending the request to the serversocket it is blocked without throwing any exception. please help me out. thanks in advance. this is my code. try { while ((len = inputStream.read(mainBuffer)) -1) { System.out.println("len= " + len); }//end of while System.out.println("out of while loop");//which is never printed on screen. } catch (IOException e) { e.printStackTrace(); } regards gunjan goyal

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  • Bitbanging a PIO on Coldfire/ucLinux

    - by G Forty
    Here's the problem: I need to program some hardware via 2 pins of the PIO (1 clock, 1 data). Timing constraints are tight - 10ms clock cycle time. All this, of course, whilst I maintain very high level services (CAN bus, TCP/IP). The downstream unit also ACKS by asserting a PIO pin, configured as an input, high. So this loop has to both read and write. I need to send 16 bits in the serial stream. Is there an established way to do this sort of thing or should I simply get the hardware guys to add a PIC or somesuch. I'd much prefer to avoid exotics like RTAI extensions at this stage. I did once see a reference to user-mode IO which implied a possible interrupt driven driver but lost track of it. Any pointers welcomed.

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  • Java BufferedReader readline blocking?

    - by tgguy
    I want to make an HTTP request and then get the response as sketched here: URLConnection c = new URL("http://foo.com").openConnection(); c.setDoOutput(true); /* write an http request here using a new OutputStreamWriter(c.getOutputStream) */ BufferedReader reader = new BufferedReader(new InputStreamReader(c.getInputStream)); reader.readLine(); But my question is, if the request I send takes a long time before a response is received, what happens in the call reader.readLine() above? Will this process stay running/runnable on the CPU or will it get taken off the CPU and be notified to wake up and run again when there is IO to be read? If it stays on the CPU, what can be done to make it get off and be notified later?

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  • printing menu in terminal and choosing an option, how to?

    - by carlos
    I'm a haskell beginner. I'm trying to make a program that shows a menu through terminal and ask user to introduce an option. Here is the code: main :: IO () main = do putStrLn "0 <- quit" putStrLn "1 <- Hello" putStr "Choose an option: " c <- getChar case c of '0' -> return () '1' -> putChar '\n' >> putStrLn "Hello World" >> main When I use this module in the ghci interpreter everything works like it's suposed to do. But if i compile this with: ghc hello.hs and run it in the terminal, it doesn't display the line "Choose an option:" before ask for a char to be introduced. I think this may be caused because of haskell lazy nature and I don't know how to fix it. Any ideas?

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  • Can I use meteor for this?

    - by nitelord
    I'm looking for a way to create an app which has a realtime web interface as well as an API which can be called by a node.js client while sharing most of its code. I'd like to be able to manage data, monitor and execute tasks inside of my app via browser, but also have an automation/scheduling program which connects to my web app and tells it to run various tasks and get results of each task. Unfortunately it doesn't look like I can connect to Meteor from the server, so I'm wondering if there's another approach? Is what I described even possible using Meteor? I have done some testing using socket.io and I think I may be able to do it this way, but Meteor seems like it'd be really great for the realtime user interface.

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  • C# move file as soon as it becomes available.

    - by m0s
    Hi, I need to accomplish the following task: Attempt to move a file. If file is locked schedule for moving as soon as it becomes available. I am using File.Move which is sufficient for my program. Now the problems are that: 1) I can't find a good way to check if the file I need to move is locked. I am catching System.IO.IOException but reading other posts around I discovered that the same exception may be thrown for different reasons as well. 2) Determining when the file gets unlocked. One way of doing this is probably using a timer/thread and checking the scheduled files lets say every 30 seconds and attempting to move them. But I hope there is a better way using FileSystemWatcher. This is a .net 3.5 winforms application. Any comments/suggestions are appreciated. Thanks for attention.

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  • How to efficiently deal with a large amount of HTML5 canvas pixel data over websockets

    - by user730569
    Using imageData = context.getImageData(0, 0, width, height); JSON.stringify(imageData.data); I grab the pixel data, convert it to a string, and then send it over the wire via websockets. However, this string can be pretty large, depending on the size of the canvas object. I tried using the compression technique found here: JavaScript implementation of Gzip but socket.io throws the error Websocket message contains invalid character(s). Is there an effective way to compress this data so that it can be sent over websockets?

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  • Why do [flush-8:16] and [jbd2/sdb2-8] occasionally use 99.99% disk IO?

    - by ændrük
    Approximately twice a week, the entire graphical interface will lock up for about 10-20 seconds without warning while I am doing simple tasks such as browsing the web or writing a paper. When this happens, GUI elements do not respond to mouse or keyboard input, and the System Monitor applet displays 100% IOWait processor usage. Today, I finally happened to have GNOME Terminal already open when the problem started. Despite other applications such as Google Chrome, Firefox, GNOME Do, and GNOME Panel being unresponsive, the terminal was usable. I ran iotop and observed that commands named [flush-8:16] and [jbd2/sdb2-8] were alternately using 99.99% IO. What are these, and how can I prevent them from causing GUI unresponsiveness? Here is dumpe2fs /dev/sdb2, if it's relevant.

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  • Any pre-rolled System.IO abstraction libraries out there for Unit Testing?

    - by Binary Worrier
    To test methods that use the file system we need to basically put System.IO behind a set of interfaces that we can then mock, I do this with a DiskIO class and interface. As my DiskIO code gets larger (and the grumblings from the we're unconvinced about this TDD thing crowd here in work get louder), I went looking for a comprehensive open source library that already does this and found . . . nothing. I may be looking in the wrong place or have approached this problem in completely the wrong way. I can't be the only idiot in this position, do these libraries exist, if so where are they? Any you've used and would recommend? Thanks P.S. I'm happy with my current approach i.e. starting with what we need, and adding only when the need arises. Unfortunately the we're unconvinced about this TDD thing crowd remain unconvinced, and think that I can't be right.

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  • Binary to Ascii and back again

    - by rross
    I'm trying to interface with a hardware device via the serial port. When I use software like Portmon to see the messages they look like this: 42 21 21 21 21 41 45 21 26 21 29 21 26 59 5F 41 30 21 2B 21 27 42 21 21 21 21 41 47 21 27 21 28 21 27 59 5D 41 32 21 2A 21 28 When I run them thru a hex to ascii converter the commands don't make sense. Are these messages in fact something different than hex? My hope was to see the messages the device is passing and emulate them using c#. What can I do to find out exactly what the messages are?

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  • How to solve "java.io.IOException: error=12, Cannot allocate memory" calling Runtime#exec()?

    - by Andrea Francia
    On my system I can't run a simple Java application that start a process. I don't know how to solve. Could you give me some hints how to solve? The program is: [root@newton sisma-acquirer]# cat prova.java import java.io.IOException; public class prova { public static void main(String[] args) throws IOException { Runtime.getRuntime().exec("ls"); } } The result is: [root@newton sisma-acquirer]# javac prova.java && java -cp . prova Exception in thread "main" java.io.IOException: Cannot run program "ls": java.io.IOException: error=12, Cannot allocate memory at java.lang.ProcessBuilder.start(ProcessBuilder.java:474) at java.lang.Runtime.exec(Runtime.java:610) at java.lang.Runtime.exec(Runtime.java:448) at java.lang.Runtime.exec(Runtime.java:345) at prova.main(prova.java:6) Caused by: java.io.IOException: java.io.IOException: error=12, Cannot allocate memory at java.lang.UNIXProcess.<init>(UNIXProcess.java:164) at java.lang.ProcessImpl.start(ProcessImpl.java:81) at java.lang.ProcessBuilder.start(ProcessBuilder.java:467) ... 4 more Configuration of the system: [root@newton sisma-acquirer]# java -version java version "1.6.0_0" OpenJDK Runtime Environment (IcedTea6 1.5) (fedora-18.b16.fc10-i386) OpenJDK Client VM (build 14.0-b15, mixed mode) [root@newton sisma-acquirer]# cat /etc/fedora-release Fedora release 10 (Cambridge) EDIT: Solution This solves my problem, I don't know exactly why: echo 0 /proc/sys/vm/overcommit_memory Up-votes for who is able to explain :) Additional informations, top output: top - 13:35:38 up 40 min, 2 users, load average: 0.43, 0.19, 0.12 Tasks: 129 total, 1 running, 128 sleeping, 0 stopped, 0 zombie Cpu(s): 1.5%us, 0.5%sy, 0.0%ni, 94.8%id, 3.2%wa, 0.0%hi, 0.0%si, 0.0%st Mem: 1033456k total, 587672k used, 445784k free, 51672k buffers Swap: 2031608k total, 0k used, 2031608k free, 188108k cached Additional informations, free output: [root@newton sisma-acquirer]# free total used free shared buffers cached Mem: 1033456 588548 444908 0 51704 188292 -/+ buffers/cache: 348552 684904 Swap: 2031608 0 2031608

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  • Why not port Linux kernel to Common Lisp?

    - by rplevy
    Conventional wisdom states that OS kernels must be written in C in order to achieve the necessary levels of performance. This has been the justification for not using more expressive high level languages. However, for a few years now implementations of Common Lisp such as SBCL have proven to be just as performant as C. What then are the arguments against redoing the kernel in a powerfully expressive language, namely Common Lisp? I don't think anyone (at least anyone who knows what they are talking about) could argue against the fact that the benefits in transparency and readability would be tremendous, not to mention all the things that can't be done in C that can be done in Lisp, but there may be implementation details that would make this a bad idea.

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  • Visual Studio 2008 Web Project error: Unable to start program http://localhost:port

    - by JookyDFW
    I am re-hashing this question because I have looked at over 50 threads in different forums and have not been able to get a resolution to my problem. Here are the specs: Windows XP SP3, Visual Studio 2008 SP1, .NET 3.5, ASP. NET MVC 2 project, IE 7 (was IE 8) Up until a few days ago I was not having any issues. It is now happening on any solution that I try to debug. I start a debug session (F5), the solution rebuilds, a VS development web server starts and then I get this error: Unable to start program http://localhost:2012/ If I open a web browser and enter the URL the application loads up. I had upgraded to IE 8 a few weeks ago and read there may be some issues so it has been uninstalled and I am currently on IE 7. Also, while IE 8 was installed I had switched my default browser to Firefox but my current default broweser is now IE7. I have reveiewed the threads on this site and others and have not been able to fix the issue. Any help would be appreciated.

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  • Ruby SerialPorts Gem

    - by Seth Archer
    Using Ruby SerialPorts Gem to interact with hardware. When I write a byte array to the hardware using a program called "Serial Port Monitor" the hardware responds correctly. However, when I write the same byte array using ruby it doesn't work unless I do a read request just before the write request. This device doesn't respond correctly with this sp = SerialPort.new(args) sp.write [200.chr, 30.chr, 6.chr, 5.chr, 1.chr, 2.chr, 0.chr, 244.chr] But it does if I add a read request before the write. Like this sp SerialPort.new(args) sp.read sp.write [200.chr, 30.chr, 6.chr, 5.chr, 1.chr, 2.chr, 0.chr, 244.chr] This works, but I'm at a loss as to why. I should also add that the first snippet does work occasionally maybe 1/10 of the time.

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  • Synchronization requirements for FileStream.(Begin/End)(Read/Write)

    - by Doug McClean
    Is the following pattern of multi-threaded calls acceptable to a .Net FileStream? Several threads calling a method like this: ulong offset = whatever; // different for each thread byte[] buffer = new byte[8192]; object state = someState; // unique for each call, hence also for each thread lock(theFile) { theFile.Seek(whatever, SeekOrigin.Begin); IAsyncResult result = theFile.BeginRead(buffer, 0, 8192, AcceptResults, state); } if(result.CompletedSynchronously) { // is it required for us to call AcceptResults ourselves in this case? // or did BeginRead already call it for us, on this thread or another? } Where AcceptResults is: void AcceptResults(IAsyncResult result) { lock(theFile) { int bytesRead = theFile.EndRead(result); // if we guarantee that the offset of the original call was at least 8192 bytes from // the end of the file, and thus all 8192 bytes exist, can the FileStream read still // actually read fewer bytes than that? // either: if(bytesRead != 8192) { Panic("Page read borked"); } // or: // issue a new call to begin read, moving the offsets into the FileStream and // the buffer, and decreasing the requested size of the read to whatever remains of the buffer } } I'm confused because the documentation seems unclear to me. For example, the FileStream class says: Any public static members of this type are thread safe. Any instance members are not guaranteed to be thread safe. But the documentation for BeginRead seems to contemplate having multiple read requests in flight: Multiple simultaneous asynchronous requests render the request completion order uncertain. Are multiple reads permitted to be in flight or not? Writes? Is this the appropriate way to secure the location of the Position of the stream between the call to Seek and the call to BeginRead? Or does that lock need to be held all the way to EndRead, hence only one read or write in flight at a time? I understand that the callback will occur on a different thread, and my handling of state, buffer handle that in a way that would permit multiple in flight reads. Further, does anyone know where in the documentation to find the answers to these questions? Or an article written by someone in the know? I've been searching and can't find anything. Relevant documentation: FileStream class Seek method BeginRead method EndRead IAsyncResult interface

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  • CherryPy sessions for same domain, different port

    - by detly
    Consider the script below. It will launch two subprocesses, each one a CherryPy app (hit Ctrl+C or whatever the KeyboardInterrupt combo is on your system to end them both). If you run it with CP 3.0 (taking care to change the 3.0/3.1 specific lines in "StartServer"), then visit: http://localhost:15002/ ...you see an empty dict. Then visit: http://localhost:15002/set?val=10 http://localhost:15002/ ...and you see the newly populated dict. Then visit: http://localhost:15012/ ...and go back to http://localhost:15002/ ...and nothing has changed. If you try the same thing with CP 3.1 (remember the lines in "StartServer"!), when you get to the last step, the dict is now empty. This happens in Windows and Debian, Python 2.5 and 2.6. You can try all sorts of things: changing to file storage, separating the storage paths... the only difference it makes is that the sessions might get merged instead of erased. I've read another post about this as well, and there's a suggestion there to put the session tools config keys in the app config rather than the global config, but I don't think that's relevant to this usage where the apps run independently. What do I do to get independent CherryPy applications to NOT interfere with each other? Note: I originally asked this on the CherryPy mailing list but haven't had a response yet so I'm trying here. I hope that's okay. import os, os.path, socket, sys import subprocess import cgi import cherrypy HTTP_PORT = 15002 HTTP_HOST = "127.0.0.1" site1conf = { 'global' : { 'server.socket_host' : HTTP_HOST, 'server.socket_port' : HTTP_PORT, 'tools.sessions.on' : True, # 'tools.sessions.storage_type': 'file', # 'tools.sessions.storage_path': '1', # 'tools.sessions.storage_path': '.', 'tools.sessions.timeout' : 1440}} site2conf = { 'global' : { 'server.socket_host' : HTTP_HOST, 'server.socket_port' : HTTP_PORT + 10, 'tools.sessions.on' : True, # 'tools.sessions.storage_type': 'file', # 'tools.sessions.storage_path': '2', # 'tools.sessions.storage_path': '.', 'tools.sessions.timeout' : 1440}} class Home(object) : def __init__(self, key): self.key = key @cherrypy.expose def index(self): return """\ <html> <body>Session: <br>%s </body> </html> """ % cgi.escape(str(dict(cherrypy.session))) @cherrypy.expose def set(self, val): cherrypy.session[self.key.upper()] = val return """\ <html> <body>Set %s to %s</body> </html>""" % (cgi.escape(self.key), cgi.escape(val)) def StartServer(conf, key): cherrypy.config.update(conf) print 'Starting server (%s)' % key cherrypy.tree.mount(Home(key), '/', {}) # Start the web server. #### 3.0 # cherrypy.server.quickstart() # cherrypy.engine.start() #### #### 3.1 cherrypy.engine.start() cherrypy.engine.block() #### def Main(): # Start first webserver proc1 = subprocess.Popen( [sys.executable, os.path.abspath(__file__), "1"]) proc2 = subprocess.Popen( [sys.executable, os.path.abspath(__file__), "2"]) proc1.wait() proc2.wait() if __name__ == "__main__": print sys.argv if len(sys.argv) == 1: # Master process Main() elif(int(sys.argv[1]) == 1): StartServer(site1conf, 'magic') elif(int(sys.argv[1]) == 2): StartServer(site2conf, 'science') else: sys.exit(1)

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  • MacPorts manual port location

    - by gok
    I am installing one library for python from MacPorts. But macports version is older than actual development svn version. Is it possible to specify a custom location for installation in MacPorts so I could install latest library from the developer's site?

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  • Where to get apache poi port for .net

    - by Nassign
    I would like to know if there is a website where I could download the Apache POI ported for .net? I already found this link in the web http://www.apache.org/~avik/dist/poi-2.5.1-dev-20040708.dll But the version of apache poi now is 3.6, I was wondering if there is a latest version out there? Does the apache foundation support such porting? I already tried to search the apache website too with no avail. As for using Microsoft library, the excel interopt is not that good for concurrent processing like a web backend. If I use the DocumentFormat.OpenXML library, I have a limitation of creating office 2007 document only.

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  • I want to port my delicious bookmarks to my website

    - by puneet
    I started building a app that will automatically download my delicious bookmarks, and save to a database, so they I can view them on my own website in my favoured format. I am forced to use oAuth, as I have a yahoo id to login to delicious. The problem is I am stuck at the point where oAuth requires a user to manually go and authenticate. Is there a code/ guidelines available anywhere I can follow? All I want is a way to automatically save my bookmarks to my database. Any help is appreciated. I can work on java, .net and php. Thanks.

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  • Port a live system from App Engine Helper to App Engine Patch

    - by Alexander
    I am running a live system that is currently serving about 20K pages a day which is based on App Engine Helper (Python) with session support provided by AppEngine utilities. One problem that I have been having is that sessions are occasionally randomly logging out. I would like to try using the App Engine Patch, since it has "native" django session support, but I am worried that this is possibly going to be like doing a brain transplant. Specifically, current database models are all inhereted from BaseModel provided by the App Engine Helper. While, App Engine Patch does not have this inheritance. Does anyone know if it is possible to migrate a live system from App Engine Helper to App Engine Patch? If so, do you have any advice or warnings that I should heed, before attempting this transition? Thank you and kind regards Alex

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  • Communication with HyperTerminal [ QT and WINApi ]

    - by javaAmator
    Hi! I write program to communicate with modem (it useing Hayes commands) and this is working. GUI is programmed with QT, but communication with COM port is write with winapi library. I have problem when I want to send with my program message from one computer to another, i can't send Polish chars (they are repleaced by '?'), how can I fix it ? Does anyone have idea ?? And I have one more problem, I can't send message from my program to Microsoft HyperTerminal, HyperTerminal receive something, but not that what I send. Thx for any help :) Important pieces of code: Connect with port: portHandle = CreateFile (portName, GENERIC_WRITE | GENERIC_READ, 0, NULL, OPEN_EXISTING, 0, NULL); GetCommState (portHandle, &dcb); switch(ui->comboBox->currentIndex()) { case 0 : dcb.BaudRate=CBR_110; break; case 1 : dcb.BaudRate=CBR_300; break; case 2 : dcb.BaudRate=CBR_600; break; case 3 : dcb.BaudRate=CBR_1200; break; case 4 : dcb.BaudRate=CBR_2400; break; case 5 : dcb.BaudRate=CBR_4800; break; case 6 : dcb.BaudRate=CBR_9600; break; case 7 : dcb.BaudRate=CBR_14400; break; case 8 : dcb.BaudRate=CBR_19200; break; case 9 : dcb.BaudRate=CBR_38400; break; case 10 : dcb.BaudRate=CBR_56000; break; case 11 : dcb.BaudRate=CBR_57600; break; case 12 : dcb.BaudRate=CBR_115200; break; case 13 : dcb.BaudRate=CBR_128000; break; case 14 : dcb.BaudRate=CBR_256000; break; } dcb.fBinary = TRUE; dcb.fParity = TRUE; dcb.fOutxCtsFlow = FALSE; dcb.fOutxDsrFlow = FALSE; dcb.fDtrControl = DTR_CONTROL_ENABLE; dcb.fDsrSensitivity = FALSE; dcb.fTXContinueOnXoff = TRUE; dcb.fOutX = FALSE; dcb.fInX = FALSE; dcb.fErrorChar = FALSE; dcb.fNull = FALSE; dcb.fRtsControl = RTS_CONTROL_ENABLE; dcb.fAbortOnError = FALSE; //dcb.ByteSize = dataBits; dcb.DCBlength = sizeof (DCB); switch(ui->comboBox_3->currentIndex()) { case 1 : dcb.Parity = EVENPARITY; break; case 3 : dcb.Parity = MARKPARITY; break; case 2 : dcb.Parity = ODDPARITY; break; case 4 : dcb.Parity = SPACEPARITY; break; case 0 : dcb.Parity = NOPARITY; break; } switch (ui->comboBox_4->currentIndex()) { case 0 : dcb.StopBits = ONESTOPBIT; break; case 1 : dcb.StopBits = ONE5STOPBITS;break; case 2 : dcb.StopBits = TWOSTOPBITS; break; } switch (ui->comboBox_2->currentIndex()) { case 0 : dcb.ByteSize = 5; break; case 1 : dcb.ByteSize = 6;break; case 2 : dcb.ByteSize= 7; break; case 3 : dcb.ByteSize = 8; break; } SetCommState (portHandle, &dcb); GetCommTimeouts (portHandle, &CommTimeouts); CommTimeouts.ReadIntervalTimeout = MAXDWORD; CommTimeouts.ReadTotalTimeoutMultiplier = 0; CommTimeouts.ReadTotalTimeoutConstant = 0; CommTimeouts.WriteTotalTimeoutMultiplier = 10; CommTimeouts.WriteTotalTimeoutConstant = 1000; SetCommTimeouts (portHandle, &CommTimeouts); Send MSG: void MainWindow::Send(char c) { do {WriteFile(portHandle, &c, 1, &cbWritten, NULL); } while (!(cbWritten)); } void MainWindow::on_pushButton_clicked() { QString str = ui->lineEdit->text(); std::string str2; ui->lineEdit->clear(); str2 = str.toStdString(); for(int i=0; i < str2.size();i++) { Send(str2[i]); //qDebug()<< str2[i]; } Send(char(13)); } Receive MSG: void ReaderThread::run() { char c; while(1) { c = Receive(); if(c==13) { emit insertPlainText("\n"); } else { emit insertPlainText(QString(c)); } } } char ReaderThread::Receive() { char c; do{ ReadFile(portHandle, &c, 1, &cbRead, NULL); } while (!(cbRead)); return c; }

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  • Programmatically Set Proxy Address, Port, User, Password throught Windows Registry

    - by Fábio Antunes
    I'm writing a small C# application that will use Internet Explorer to interact with a couple a websites, with help from WatiN. However, it will also require from time to time to use a proxy. I've came across Programmatically Set Browser Proxy Settings in C#, but this only enables me to enter a proxy address, and I also need to enter a Proxy username and password. How can I do that? Note: It doesn't matter if a solution changes the entire system Internet settings. However, I would prefer to change only IE proxy settings (for any connection). The solution has to work with IE8 and Windows XP SP3 or higher. I'd like to have the possibility to read the Proxy settings first, so that later I can undo my changes. EDIT With the help of the Windows Registry accessible through Microsoft.Win32.RegistryKey, i was able to apply a proxy something like this: RegistryKey registry = Registry.CurrentUser.OpenSubKey("Software\\Microsoft\\Windows\\CurrentVersion\\Internet Settings", true); registry.SetValue("ProxyEnable", 1); registry.SetValue("ProxyServer", "127.0.0.1:8080"); But how can i specify a username and a password to login at the proxy server? I also noticed that IE doesn't refresh the Proxy details for its connections once the registry was changed how can i order IE to refresh its connection settings from the registry? Thanks

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