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How to show percentage of 'memory used' in a win32 process?

- by pj4533

I know that memory usage is a very complex issue on Windows. I am trying to write a UI control for a large application that shows a 'percentage of memory used' number, in order to give the user an indication that it may be time to clear up some memory, or more likely restart the application. One implementation used ullAvailVirtual from MEMORYSTATUSEX as a base, then used HeapWalk() to walk the process heap looking for additional free memory. The HeapWalk() step was needed because we noticed that after a while of running the memory allocated and freed by the heap was never returned and reported by the ullAvailVirtual number. After hours of intensive working, the ullAvailVirtual number no longer would accurately report the amount of memory available. However, this method proved not ideal, due to occasional odd errors that HeapWalk() would return, even when the process heap was not corrupted. Further, since this is a UI control, the heap walking code was executing every 5-10 seconds. I tried contacting Microsoft about why HeapWalk() was failing, escalated a case via MSDN, but never got an answer other than "you probably shouldn't do that". So, as a second implementation, I used PagefileUsage from PROCESS_MEMORY_COUNTERS as a base. Then I used VirtualQueryEx to walk the virtual address space adding up all regions that weren't MEM_FREE and returned a value for GetMappedFileNameA(). My thinking was that the PageFileUsage was essentially 'private bytes' so if I added to that value the total size of the DLLs my process was using, it would be a good approximation of the amount of memory my process was using. This second method seems to (sorta) work, at least it doesn't cause crashes like the heap walker method. However, when both methods are enabled, the values are not the same. So one of the methods is wrong. So, StackOverflow world...how would you implement this? which method is more promising, or do you have a third, better method? should I go back to the original method, and further debug the odd errors? should I stay away from walking the heap every 5-10 seconds? Keep in mind the whole point is to indicate to the user that it is getting 'dangerous', and they should either free up memory or restart the application. Perhaps a 'percentage used' isn't the best solution to this problem? What is? Another idea I had was a color based system (red, yellow, green, which I could base on more factors than just a single number)

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How hard programming is? Really. [closed]

- by Bubba88

Hi! The question is about your perception of programming activity. How hard/exacting this task is? There is much buzz about programming nowadays, people say that programmers are smart, very technical and abstract at a time, know much about world, psychology etc.. They say, that programmers got really powerful brain thing, cause there is much to keep in consideration simultaneously again with much information folded into each other associatively (up 10 levels of folding they say))) Still, there are some terms to specify at our own.. So that is the question: What do you think about programming in general? Is it hard? Is it 'for everyone' or for the particular kind of people only? How much non-CS background do you need to program (just to program, really; enterprise applications for example)? How long is the learning curve? (again, for programming in general) And another bunch of random questions: - If you were not to like/love programming, would that be a serious trouble bothering your current employment? - If you were to start from the beginning, would you chose that direction this time? - What other areas (jobs or maybe hobbies) are comparable to programming in the way they can explode someone's lovely brain? - Is 'non turing-complete programming' (SQL, XML, etc.) comparable to what we do or is it really way easier, less requiring, cheap and akin to cooking :)? Well, the essence is: How would you describe programming activity WRT to its difficulty? Or, on the other hand: Did you ever catch yourself thinking at some point: OMG, it's sooo hard! I don't know how would I ever program, even carried away this way and doing programming just for fun? It's very interesting to know your opinion, your'e the programmers after all. I mean much people must be exaggerating/speculating about the thing they do not really know about. But that musn't be the case here on SO :) P.S.: I'll try my best to update this post later, and you please edit it too. At least I'll get decent English in my question text :)

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HttpSession problem in Google App Engine/J

- by Tahir Akram

I am writting a Twitter web app by using Twitter4J on GAE/J. I am saving Twitter and Request Token objects in session so that to be used after call back. I have two servlets. IndexServlet sets session and HomeServlet get from session (hits on call back by twitter oAuth). If I comment out session handling lines in both servlets then call backs works fine. Please suggest any workaround. I am sharing my code here. IndexServlet.java Twitter twitter = new Twitter(); twitter.setOAuthConsumer("<masked>", "<masked>"); RequestToken requestToken = null; try { requestToken = twitter.getOAuthRequestToken(); log.info("OAuth token has been taken"); } catch (TwitterException e) { log.warning(e.toString()); } HttpSession session = request.getSession(); if (session.getAttribute("twitter")==null){ session.setAttribute("twitter", twitter); out.println("-----------------------------> session is set"); } if (session.getAttribute("token")==null){ session.setAttribute("token", requestToken); out.println("-----------------------------> session is set"); } String authUrl = requestToken.getAuthorizationURL(); HomeServlet.java HttpSession session = request.getSession(); twitter = (Twitter)session.getAttribute("twitter"); r = (RequestToken)session.getAttribute("token"); twitter.setOAuthAccessToken(r.getAccessToken()); twitter.updateStatus("Hello World!"); Exception javax.servlet.ServletException: java.lang.ArrayStoreException: [Ljava.lang.String; at com.google.apphosting.runtime.jetty.AppVersionHandlerMap.handle(AppVersionHandlerMap.java:239) at org.mortbay.jetty.handler.HandlerWrapper.handle(HandlerWrapper.java:139) at org.mortbay.jetty.Server.handle(Server.java:313) at org.mortbay.jetty.HttpConnection.handleRequest(HttpConnection.java:506) at org.mortbay.jetty.HttpConnection$RequestHandler.headerComplete(HttpConnection.java:830) at com.google.apphosting.runtime.jetty.RpcRequestParser.parseAvailable(RpcRequestParser.java:76) at org.mortbay.jetty.HttpConnection.handle(HttpConnection.java:381) at com.google.apphosting.runtime.jetty.JettyServletEngineAdapter.serviceRequest(JettyServletEngineAdapter.java:139) at com.google.apphosting.runtime.JavaRuntime.handleRequest(JavaRuntime.java:235) at com.google.apphosting.base.RuntimePb$EvaluationRuntime$6.handleBlockingRequest(RuntimePb.java:4950) at com.google.apphosting.base.RuntimePb$EvaluationRuntime$6.handleBlockingRequest(RuntimePb.java:4948) at com.google.net.rpc.impl.BlockingApplicationHandler.handleRequest(BlockingApplicationHandler.java:24) at com.google.net.rpc.impl.RpcUtil.runRpcInApplication(RpcUtil.java:359) at com.google.net.rpc.impl.Server$2.run(Server.java:823) at com.google.tracing.LocalTraceSpanRunnable.run(LocalTraceSpanRunnable.java:56)

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What could cause a Labwindows/CVI C program to hate the number 2573?

- by Adam Bard

Using Windows So I'm reading from a binary file a list of unsigned int data values. The file contains a number of datasets listed sequentially. Here's the function to read a single dataset from a char* pointing to the start of it: function read_dataset(char* stream, t_dataset *dataset){ //...some init, including setting dataset->size; for(i=0;i<dataset->size;i++){ dataset->samples[i] = *((unsigned int *) stream); stream += sizeof(unsigned int); } //... } Where read_dataset in such a context as this: //... char buff[10000]; t_dataset* dataset = malloc( sizeof( *dataset) ); unsigned long offset = 0; for(i=0;i<number_of_datasets; i++){ fseek(fd_in, offset, SEEK_SET); if( (n = fread(buff, sizeof(char), sizeof(*dataset), fd_in)) != sizeof(*dataset) ){ break; } read_dataset(buff, *dataset); // Do something with dataset here. It's screwed up before this, I checked. offset += profileSize; } //... Everything goes swimmingly until my loop reads the number 2573. All of a sudden it starts spitting out random and huge numbers. For example, what should be ... 1831 2229 2406 2637 2609 2573 2523 2247 ... becomes ... 1831 2229 2406 2637 2609 0xDB00000A 0xC7000009 0xB2000008 ... If you think those hex numbers look suspicious, you're right. Turns out the hex values for the values that were changed are really familiar: 2573 -> 0xA0D 2523 -> 0x9DB 2247 -> 0x8C7 So apparently this number 2573 causes my stream pointer to gain a byte. This remains until the next dataset is loaded and parsed, and god forbid it contain a number 2573. I have checked a number of spots where this happens, and each one I've checked began on 2573. I admit I'm not so talented in the world of C. What could cause this is completely and entirely opaque to me.

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Qt - problem appending to QList of QList

- by bullettime

I'm trying to append items to a QList at runtime, but I'm running on a error message. Basically what I'm trying to do is to make a QList of QLists and add a few customClass objects to each of the inner lists. Here's my code: widget.h: class Widget : public QWidget { Q_OBJECT public: Widget(QWidget *parent = 0); ~Widget(); public slots: static QList<QList<customClass> > testlist(){ QList<QList<customClass> > mylist; for(int w=0 ; w<5 ; w++){ mylist.append(QList<customClass>()); } for(int z=0 ; z<mylist.size() ; z++){ for(int x=0 ; x<10 ; x++){ customClass co = customClass(); mylist.at(z).append(co); } } return mylist; } }; customclass.h: class customClass { public: customClass(){ this->varInt = 1; this->varQString = "hello world"; } int varInt; QString varQString; }; main.cpp: int main(int argc, char *argv[]) { QApplication a(argc, argv); Widget w; QList<QList<customClass> > list; list = w.testlist(); w.show(); return a.exec(); } But when I try to run the application, it gives off this error: error: passing `const QList<customClass>' as `this' argument of `void List<T>::append(const T&) [with T = customClass]' discards qualifiers I also tried inserting the objects using foreach: foreach(QList<customClass> list, mylist){ for(int x=0 ; x<10 ; x++){ list.append(customClass()); } } The error was gone, but the customClass objects weren't appended, I could verify that by using a debugging loop in main that showed the inner QLists sizes as zero. What am I doing wrong?

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(PHP) User is being forced to RE-LOGIN after trying to do something on an admin page

- by hatorade

I have created an admin panel for a client in PHP, which requires a login. Here is the code at the top of the admin page requiring the user to be logged in: admin.php <?php session_start(); require("_lib/session_functions.php"); require("_lib/db.php"); db_connect(); //if the user has not logged in if(!isLoggedIn()) { header('Location: login_form.php'); die(); } ?> Obviously, the if statement is what catches them and forces them to log in. Here is the code on the resulting login page: login_form.php <form name="login" action="login.php" method="post"> Username: <input type="text" name="username" /> Password: <input type="password" name="password" /> <input type="submit" value="Login" /> </form> Which posts info to this controller page: login.php <?php session_start(); //must call session_start before using any $_SESSION variables include '_lib/session_functions.php'; $username = $_POST['username']; $password = $_POST['password']; include '_lib/db.php'; db_connect(); // Connect to the DB $username = mysql_real_escape_string($username); $query = "SELECT password, salt FROM users WHERE username = '$username';"; $result = mysql_query($query); if(mysql_num_rows($result) < 1) //no such user exists { header('Location: login_form.php?login=fail'); die(); } $userData = mysql_fetch_array($result, MYSQL_ASSOC); db_disconnect(); $hash = hash('sha256', $password . $userData['salt']); if($hash != $userData['password']) //incorrect password { header('Location: login_form.php?login=fail'); die(); } else { validateUser(); //sets the session data for this user } header('Location: admin.php'); ?> and the session functions page that provides login functions contains this: session_functions.php <?php function validateUser() { session_regenerate_id (); //this is a security measure $_SESSION['valid'] = 1; $_SESSION['userid'] = $username; } function isLoggedIn() { if($_SESSION['valid']) return true; return false; } function logout() { $_SESSION = array(); //destroy all of the session variables if (ini_get("session.use_cookies")) { $params = session_get_cookie_params(); setcookie(session_name(), '', time() - 42000, $params["path"], $params["domain"], $params["secure"], $params["httponly"] ); } session_destroy(); } ?> I grabbed the sessions_functions.php code of an online tutorial, so it could be suspicious. Any ideas why the user logs in to the admin panel, tries to do something, is forced to re-login, and THEN is allowed to do stuff like normal in the admin panel?

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Unable to use NSURLConnection to get contents of password/username protected webpage

- by bubster

I am trying to get the contents of a webpage that requires a password and user name to access. I am using a NSURLConnection object to get it however when I write the NSMutableData object that is returned to a file all I get is the login page. Normally when you try to load the password protected page when you are not logged in it redirects to the login page however I thought that if I provided valid credentials then this I would be able to view the password protected page. Also I do not know if it is relevant the website is using a microsoft mysql database on an IIS (internet information server). Note: [protectionSpace authenticationMethod] returns NSURLAuthenticationMethodServerTrust I am pretty unfamiliar with this so any ideas would be greatly appreciated. Below is all of the relevant code: - (void)connection:(NSURLConnection *)connection didReceiveResponse:(NSURLResponse *)response { // This method is called when the server has determined that it // has enough information to create the NSURLResponse. // It can be called multiple times, for example in the case of a // redirect, so each time we reset the data. // receivedData is an instance variable declared elsewhere. [receivedData setLength:0]; } - (void)connection:(NSURLConnection *)connection didReceiveData:(NSData *)data { // Append the new data to receivedData. // receivedData is an instance variable declared elsewhere. [receivedData appendData:data]; } - (void)connection:(NSURLConnection *)connection didFailWithError:(NSError *)error { // release the connection, and the data object //[connection release]; // receivedData is declared as a method instance elsewhere //[receivedData release]; // inform the user NSLog(@"Connection failed! Error - %@ %@", [error localizedDescription], [[error userInfo] objectForKey:NSURLErrorFailingURLStringErrorKey]); } - (void)connectionDidFinishLoading:(NSURLConnection *)connection { // do something with the data // receivedData is declared as a method instance elsewhere NSLog(@"Succeeded! Received %d bytes of data",[receivedData length]); // release the connection, and the data object //[connection release]; //[receivedData release]; //Write data to a file [receivedData writeToFile:@"/Users/matsallen/Desktop/receivedData.html" atomically:YES]; } - (BOOL)connection:(NSURLConnection *)connection canAuthenticateAgainstProtectionSpace: (NSURLProtectionSpace *)protectionSpace { NSLog(@"The connection encountered a protection space. The authentication method is %@", [protectionSpace authenticationMethod]); secureTrustReference = [protectionSpace serverTrust]; //SecTrustResultType *result; //OSStatus status = SecTrustEvaluate(secureTrustReference, result); //NSLog(@"Result of the trust evaluation is %@",status); return YES; } - (void)connection:(NSURLConnection *)connection didReceiveAuthenticationChallenge:(NSURLAuthenticationChallenge *)challenge { NSURLCredential *newCredential; newCredential = [NSURLCredential credentialWithUser:@"username" password:@"password" persistence:NSURLCredentialPersistenceForSession]; newCredential = [NSURLCredential credentialForTrust:secureTrustReference]; // [[challenge sender] useCredential:newCredential forAuthenticationChallenge:challenge]; // [[challenge sender] continueWithoutCredentialForAuthenticationChallenge:challenge]; } #pragma mark - View lifecycle - (void)viewDidLoad { receivedData = [[NSMutableData alloc] init]; [super viewDidLoad]; // Do any additional setup after loading the view, typically from a nib. // Create the request. NSURLRequest *theRequest=[NSURLRequest requestWithURL:[NSURL URLWithString:@"https://www.markallenonline.com/secure/maoCoaching.aspx"] cachePolicy:NSURLRequestUseProtocolCachePolicy timeoutInterval:60.0]; // create the connection with the request // and start loading the data NSURLConnection *theConnection=[[NSURLConnection alloc] initWithRequest:theRequest delegate:self]; if (theConnection) { // Create the NSMutableData to hold the received data. // receivedData is an instance variable declared elsewhere. receivedData = [NSMutableData data]; NSLog(@"Connection succeeded!"); } else { // Inform the user that the connection failed. NSLog(@"Connection failed!"); } }

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FreeBSD high load loopback interface

- by user1740915

I have a problem with a FreeBSD server. There is a FreeBSD 9.0 amd64, two network cards em1 (internet), em0 (local network) configured firewall ipfw, natd, squid (not transparent), the server acts as a gateway for access to the Internet. Next problem: upload via squid is very low. At this moment I see next: natd, dhcpd load the cpu at that time when uploading through squid and there are a lot of traffic through the loopback interface. ipfw show output 0100 655389684 36707144666 allow ip from any to any via lo0 00200 0 0 deny ip from any to 127.0.0.0/8 00300 0 0 deny ip from 127.0.0.0/8 to any 00400 0 0 deny ip from any to ::1 00500 0 0 deny ip from ::1 to any 00600 4 292 allow ipv6-icmp from :: to ff02::/16 00700 0 0 allow ipv6-icmp from fe80::/10 to fe80::/10 00800 1 76 allow ipv6-icmp from fe80::/10 to ff02::/16 00900 0 0 allow ipv6-icmp from any to any ip6 icmp6types 1 01000 0 0 allow ipv6-icmp from any to any ip6 icmp6types 2,135,136 01100 1615 76160 deny ip from 192.168.1.1 to any in via em1 01200 0 0 deny ip from 199.69.99.11 to any in via em0 01300 46652 3705426 deny ip from any to 172.16.0.0/12 via em1 01400 3936404 345618870 deny ip from any to 192.168.0.0/16 via em1 01500 4 336 deny ip from any to 0.0.0.0/8 via em1 01600 4129 387621 deny ip from any to 169.254.0.0/16 via em1 01700 0 0 deny ip from any to 192.0.2.0/24 via em1 01800 917566 33777571 deny ip from any to 224.0.0.0/4 via em1 01900 147872 22029252 deny ip from any to 240.0.0.0/4 via em1 02000 1132194739 1190981955947 divert 8668 ip4 from any to any via em1 02100 3 248 deny ip from 172.16.0.0/12 to any via em1 02200 35925 2281289 deny ip from 192.168.0.0/16 to any via em1 02300 1808 122494 deny ip from 0.0.0.0/8 to any via em1 02400 3 174 deny ip from 169.254.0.0/16 to any via em1 02500 0 0 deny ip from 192.0.2.0/24 to any via em1 02600 0 0 deny ip from 224.0.0.0/4 to any via em1 02700 0 0 deny ip from 240.0.0.0/4 to any via em1 02800 960156249 1095316736582 allow tcp from any to any established 02900 64236062 8243196577 allow ip from any to any frag 03000 34 1756 allow tcp from any to me dst-port 25 setup 03100 193 11580 allow tcp from any to me dst-port 53 setup 03200 63 4222 allow udp from any to me dst-port 53 03300 64 8350 allow udp from me 53 to any 03400 417 24140 allow tcp from any to me dst-port 80 setup 03500 211 10472 allow ip from any to me dst-port 3389 setup 05300 77 4488 allow ip from any to me dst-port 1723 setup 05400 3 156 allow ip from any to me dst-port 8443 setup 05500 9882 590596 allow tcp from any to me dst-port 22 setup 05600 1 60 allow ip from any to me dst-port 2000 setup 05700 0 0 allow ip from any to me dst-port 2201 setup 07400 4241779 216690096 deny log logamount 1000 ip4 from any to any in via em1 setup proto tcp 07500 21135656 1048824936 allow tcp from any to any setup 07600 474447 35298081 allow udp from me to any dst-port 53 keep-state 07700 532 40612 allow udp from me to any dst-port 123 keep-state 65535 1990638432 1122305322718 allow ip from any to any systat -ifstat when uploading via squid Load Average ||| Interface Traffic Peak Total tun0 in 79.507 KB/s 232.479 KB/s 42.314 GB out 2.022 MB/s 2.424 MB/s 59.662 GB lo0 in 4.450 MB/s 4.450 MB/s 43.723 GB out 4.450 MB/s 4.450 MB/s 43.723 GB em1 in 2.629 MB/s 2.982 MB/s 464.533 GB out 2.493 MB/s 2.875 MB/s 484.673 GB em0 in 240.458 KB/s 296.941 KB/s 442.368 GB out 512.508 KB/s 850.857 KB/s 416.122 GB top output PID USERNAME THR PRI NICE SIZE RES STATE C TIME WCPU COMMAND 66885 root 1 92 0 26672K 2784K CPU3 3 528:43 65.48% natd 9160 dhcpd 1 45 0 31032K 9280K CPU1 1 7:40 32.96% dhcpd 66455 root 1 20 0 18344K 2856K select 1 119:27 1.37% openvpn 16043 squid 1 20 0 44404K 17884K kqread 2 0:22 0.29% squid squid.conf cat /usr/local/etc/squid/squid.conf # # Recommended minimum configuration: # acl manager proto cache_object acl localhost src 127.0.0.1/32 ::1 acl to_localhost dst 127.0.0.0/8 0.0.0.0/32 ::1 # Example rule allowing access from your local networks. # Adapt to list your (internal) IP networks from where browsing # should be allowed acl localnet src 10.0.0.0/8 # RFC1918 possible internal network acl localnet src 172.16.0.0/12 # RFC1918 possible internal network acl localnet src 192.168.0.0/16 # RFC1918 possible internal network acl localnet src fc00::/7 # RFC 4193 local private network range acl localnet src fe80::/10 # RFC 4291 link-local (directly plugged) machines acl SSL_ports port 443 acl Safe_ports port 80 # http acl Safe_ports port 21 # ftp acl Safe_ports port 443 # https acl Safe_ports port 70 # gopher acl Safe_ports port 210 # wais acl Safe_ports port 1025-65535 # unregistered ports acl Safe_ports port 280 # http-mgmt acl Safe_ports port 488 # gss-http acl Safe_ports port 591 # filemaker acl Safe_ports port 777 # multiling http acl CONNECT method CONNECT # # Recommended minimum Access Permission configuration: # # Only allow cachemgr access from localhost http_access allow manager localhost http_access deny manager # Deny requests to certain unsafe ports http_access deny !Safe_ports # Deny CONNECT to other than secure SSL ports http_access deny CONNECT !SSL_ports # We strongly recommend the following be uncommented to protect innocent # web applications running on the proxy server who think the only # one who can access services on "localhost" is a local user http_access deny to_localhost # # INSERT YOUR OWN RULE(S) HERE TO ALLOW ACCESS FROM YOUR CLIENTS # # Example rule allowing access from your local networks. # Adapt localnet in the ACL section to list your (internal) IP networks # from where browsing should be allowed http_access allow localnet http_access allow localhost # And finally deny all other access to this proxy http_access deny all # Squid normally listens to port 3128 http_port 192.168.1.1:3128 # Uncomment and adjust the following to add a disk cache directory. #cache_dir ufs /var/squid/cache 100 16 256 # Leave coredumps in the first cache dir coredump_dir /var/squid/cache I understand that the traffic passes through the SQUID several times. But can not find why.

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Direct show video renderers suck?

- by Daniel

So I've been looking into the world of media playback for windows and I've started making a C# Media Player using DirectShow. I started off using the VRM-7 windowed video renderer and it was brilliant except it had a couple of small problems (multi monitors, fullscreen). But after some research I found that it's deprecated and I should be using VRM9. So I changed it to use VRM9 windowless then found out that was an old post rofl _< so finally I'm using Vista/Win7 (or XP .net 3) Enhanced Video Renderer (EVR) which is apparently the most up to date Microsoft video renderer and has all the flashy performance/quality things added to it. (tbh I haven't noticed any difference but maybe I need a blue-ray or HQ video to notice it). With using EVR everything is working fine except resizing the video. Its really laggy/choppy/teary and problem something to do with its frame queueing mechanism. To demonstrate my problem open up windows media player classic. View - Options - Playback - output Chose the "EVR" DirectShow Video renderer Now restart wmp class and play a video, while it's playing click and drag a corner to resize it. You'll notice its horribly laggy. This is the exact same problem i am having. But if you chose "EVR Custom Pres. *" or EVR Sync *" resizing works beautifully! So i tried googling around for anything about EVR resizing issues and how to fix it but i couldn't believe how little i could find. I'm guessing "Custom Pres." stands for "Custom Presenter" which sounds like they made their own. Also you'll notice on the right hand size when you swap between EVR and the other EVR's the Resizer drop down on the right greys out. So basically I wan't to know how I can fix this retarded resizing problem and is there any decent documentation out there? There is a fair bit for VMR7/9 but not much for EVR. I downloaded the DirectX SDK which apparently has samples but it was a waste of 500mb of bandwidth as it had nothing relevant. Perhaps there is some way to force it not queueing up frames if that is the problem? If you want code say the word and I'll paste some in. But it's really quite simple and nothing much happens, i'm convinced it's a problem with the EVR renderer. EDIT: Oh and one other thing, what does VLC use? If you go into vlc options and change the renderer to anything but default, they all suck. So is it using VMR7? Or its own?

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How do we, as a community, help encourage programming in public schools? (Or state Schools for the U

- by NoMoreZealots

PRIMARY MOTIVATION My office gets involved with the "First Robotics" competitions and one thing that lingers year to year is the students typically have no preparation for doing even simple programming as part of the public schools system. While the science classes provide some basic grasp of mechanical and electrical concepts, by in large computer programming gets no coverage from the curriculum. (This my be different in other areas of the country/world.) What makes it worse is there is only a short period of time you have to prepare the student's and help them design the robot. Talking to some professors from local colleges, it's a problem because you can't assume even the most basic understanding for freshman CS majors. Languages like Python, Lua and BASIC are simple enough for at least high school level students, if not younger. SCOPE So how do you get public schools to support a programming, at least to the level of "Try it in BASIC" examples that used to be at the end of a chapter in my Algebra book? At least enough to prepare them for event's such as the FIRST Robotic competitions. Which the primary objectives are to teach problem solving and team work, and to possible foster an interest in Math, Science and Engineering in general. (Not force feed to them, as some people her seem to be implying.) Edit: Why teach kids: (Since 2000 CS enrollment in US colleges has decreased by 70% while college enrollment has increased, this is a PROBLEM.) Saying there is no value in teaching someone programming in Jr./High school because they might think "they know programming." Is like saying there's no value in teaching High school science and physics, because they might decide they "know physics." Leading to abuse like: "I passed a high school physics class, I'm going to develop a Unified Quantum Gravitational Theory." Better Prepared students are better students. Instead it would allows college programs to raise the bar on the entry level courses, allowing students to be weeded out based on their understanding of more advanced material. Plus people who did poorly in that in topic in High school aren't as likely to say "I think there's money in computer's so I'll computer science." Plus if people take it in high school and decide THEN that it's not for them, it's better than them wasting their money to PAY a college to figure that out. The result is that people who take the degree are more likely to succeed and be there for the RIGHT reasons. (i.e. It's what they REALLY want to do. And that's REALLY the key to being good at anything.) Programming is like anything else, the more practice and genuine interest you have the better you get. If you start them later, they get less practice. The earlier give them the opportunity to start, the more practice they will get. All other things equal, the more practice the better the programmer.

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DirectShow EVR resizing window problem

- by Daniel

So I've been looking into the world of media playback for windows and I've started making a C# Media Player using DirectShow. I started off using the VRM-7 windowed video renderer and it was brilliant except it had a couple of small problems (multi monitors, fullscreen). But after some research I found that it's deprecated and I should be using VRM9. So I changed it to use VRM9 windowless then found out that was an old post rofl _< so finally I'm using Vista/Win7 (or XP .net 3) Enhanced Video Renderer (EVR) which is apparently the most up to date Microsoft video renderer and has all the flashy performance/quality things added to it. (tbh I haven't noticed any difference but maybe I need a blue-ray or HQ video to notice it). With using EVR everything is working fine except resizing the video. Its really laggy/choppy/teary and probably something to do with its frame queueing mechanism. To demonstrate my problem open up windows media player classic. View - Options - Playback - output Chose the "EVR" DirectShow Video renderer Now restart wmp class and play a video, while it's playing click and drag a corner to resize it. You'll notice its horribly laggy. This is the exact same problem i am having. But if you chose "EVR Custom Pres. *" or EVR Sync *" resizing works beautifully! So i tried googling around for anything about EVR resizing issues and how to fix it but i couldn't believe how little i could find. I'm guessing "Custom Pres." stands for "Custom Presenter" which sounds like they made their own. Also you'll notice on the right hand size when you swap between EVR and the other EVR's the Resizer drop down on the right greys out. So basically I wan't to know how I can fix this retarded resizing problem and is there any decent documentation out there? There is a fair bit for VMR7/9 but not much for EVR. I downloaded the DirectX SDK which apparently has samples but it was a waste of 500mb of bandwidth as it had nothing relevant. Perhaps there is some way to force it not queueing up frames if that is the problem? If you want code say the word and I'll paste some in. But it's really quite simple and nothing much happens, i'm convinced it's a problem with the EVR renderer. EDIT: Oh and one other thing, what does VLC use? If you go into vlc options and change the renderer to anything but default, they all suck. So is it using VMR7? Or its own?

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Drawing text to <canvas> with @font-face does not work at the first time

- by lemonedo

Hi all, First try the test case please: http://lemon-factory.net/test/font-face-and-canvas.html I'm not good at English, so I made the test case to be self-explanatory. On the first click to the DRAW button, it will not draw text, or will draw with an incorrect typeface instead of the specified "PressStart", according to your browser. After then it works as expected. At the first time the text does not appear correctly in all browsers I've tested (Firefox, Google Chrome, Safari, Opera). Is it the standard behavior or something? Thank you. PS: Following is the code of the test case <!DOCTYPE html> <html> <head> <meta http-equiv=Content-Type content="text/html;charset=utf-8"> <title>@font-face and canvas</title> <style> @font-face { font-family: 'PressStart'; src: url('http://lemon-factory.net/css/fonts/prstart.ttf'); } canvas, pre { border: 1px solid #666; } pre { float: left; margin: .5em; padding: .5em; } </style> </head> <body> <div> <canvas id=canvas width=250 height=250> Your browser does not support the CANVAS element. Try the latest Firefox, Google Chrome, Safari or Opera. </canvas> <button>DRAW</button> </div> <pre id=style></pre> <pre id=script></pre> <script src="http://ajax.googleapis.com/ajax/libs/jquery/1.4.2/jquery.min.js"></script> <script> var canvas = document.getElementById('canvas') var ctx = canvas.getContext('2d') var x = 30 var y = 10 function draw() { ctx.font = '12px PressStart' ctx.fillStyle = '#000' ctx.fillText('Hello, world!', x, y += 20) ctx.fillRect(x - 20, y - 10, 10, 10) } $('button').click(draw) $('pre#style').text($('style').text()) $('pre#script').text($('script').text()) </script> </body> </html>

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XML validation in Java - why does this fail?

- by jd

hi, first time dealing with xml, so please be patient. the code below is probably evil in a million ways (I'd be very happy to hear about all of them), but the main problem is of course that it doesn't work :-) public class Test { private static final String JSDL_SCHEMA_URL = "http://schemas.ggf.org/jsdl/2005/11/jsdl"; private static final String JSDL_POSIX_APPLICATION_SCHEMA_URL = "http://schemas.ggf.org/jsdl/2005/11/jsdl-posix"; public static void main(String[] args) { System.out.println(Test.createJSDLDescription("/bin/echo", "hello world")); } private static String createJSDLDescription(String execName, String args) { Document jsdlJobDefinitionDocument = getJSDLJobDefinitionDocument(); String xmlString = null; // create the elements Element jobDescription = jsdlJobDefinitionDocument.createElement("JobDescription"); Element application = jsdlJobDefinitionDocument.createElement("Application"); Element posixApplication = jsdlJobDefinitionDocument.createElementNS(JSDL_POSIX_APPLICATION_SCHEMA_URL, "POSIXApplication"); Element executable = jsdlJobDefinitionDocument.createElement("Executable"); executable.setTextContent(execName); Element argument = jsdlJobDefinitionDocument.createElement("Argument"); argument.setTextContent(args); //join them into a tree posixApplication.appendChild(executable); posixApplication.appendChild(argument); application.appendChild(posixApplication); jobDescription.appendChild(application); jsdlJobDefinitionDocument.getDocumentElement().appendChild(jobDescription); DOMSource source = new DOMSource(jsdlJobDefinitionDocument); validateXML(source); try { Transformer transformer = TransformerFactory.newInstance().newTransformer(); transformer.setOutputProperty(OutputKeys.INDENT, "yes"); StreamResult result = new StreamResult(new StringWriter()); transformer.transform(source, result); xmlString = result.getWriter().toString(); } catch (Exception e) { e.printStackTrace(); } return xmlString; } private static Document getJSDLJobDefinitionDocument() { DocumentBuilderFactory factory = DocumentBuilderFactory.newInstance(); DocumentBuilder builder = null; try { builder = factory.newDocumentBuilder(); } catch (Exception e) { e.printStackTrace(); } DOMImplementation domImpl = builder.getDOMImplementation(); Document theDocument = domImpl.createDocument(JSDL_SCHEMA_URL, "JobDefinition", null); return theDocument; } private static void validateXML(DOMSource source) { try { URL schemaFile = new URL(JSDL_SCHEMA_URL); Sche maFactory schemaFactory = SchemaFactory.newInstance(XMLConstants.W3C_XML_SCHEMA_NS_URI); Schema schema = schemaFactory.newSchema(schemaFile); Validator validator = schema.newValidator(); DOMResult result = new DOMResult(); validator.validate(source, result); System.out.println("is valid"); } catch (Exception e) { e.printStackTrace(); } } } it spits out a somewhat odd message: org.xml.sax.SAXParseException: cvc-complex-type.2.4.a: Invalid content was found starting with element 'JobDescription'. One of '{"http://schemas.ggf.org/jsdl/2005/11/jsdl":JobDescription}' is expected. Where am I going wrong here? Thanks a lot

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Need help configurating my Tomcat server

- by gablin

I just reinstalled my entire server, and now I can't seem to get my JSP-based website to work on Tomcat anymore. I use the same server.xml file, which worked perfectly before the reinstallation, but no longer. Here's the content of the server.xml file which worked before:  <Listener className="org.apache.catalina.core.AprLifecycleListener" SSLEngine="on" />  <Listener className="org.apache.catalina.core.JasperListener" />  <Listener className="org.apache.catalina.mbeans.ServerLifecycleListener" /> <Listener className="org.apache.catalina.mbeans.GlobalResourcesLifecycleListener" />  <GlobalNamingResources>  <Resource name="UserDatabase" auth="Container" type="org.apache.catalina.UserDatabase" description="User database that can be updated and saved" factory="org.apache.catalina.users.MemoryUserDatabaseFactory" pathname="conf/tomcat-users.xml" /> </GlobalNamingResources>  <Service name="Catalina">    <Connector port="8080" protocol="HTTP/1.1" connectionTimeout="20000" redirectPort="8443" />      <Connector port="8009" protocol="AJP/1.3" redirectPort="8443" />   <Engine name="Catalina" defaultHost="localhost">      <Realm className="org.apache.catalina.realm.UserDatabaseRealm" resourceName="UserDatabase"/>        <Host name="www.rebootradio.nu"> <Alias>rebootradio.nu</Alias> <Context path="" docBase="D:/services/http/rebootradio.nu" debug="1" reloadable="true"/> </Host> </Engine> </Service> </Server> The JSP site doesn't use any WAR files or anything like that; there's just a default.jsp in the specified folder D:/services/http/rebootradio.nu which loads the site. As I said, this configuration worked before, but now with the latest verion of XAMPP and Tomcat it doesn't work anymore. All I get is a 404 message saying The requested resource () is not available.

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Move options between multiple dropdown lists

- by Martha

We currently have a form with the standard multi-select functionality of "here are the available options, here are the selected options, here are some buttons to move stuff back and forth." However, the client now wants the ability to not just select certain items, but to also categorize them. For example, given a list of books, they want to not just select the ones they own, but also the ones they've read, the ones they would like to read, and the ones they've heard about. (All examples fictional.) Thankfully, a selected item can only be in one category at a time. I can find many examples of moving items between listboxes, but not a single one for moving items between multiple listboxes. To add to the complication, the form needs to have two sets of list+categories, e.g. a list of movies that need to be categorized in addition to the aforementioned books. An additional problem is that sorting between lists is all well and good in the javascript-enabled world, but I can't really think of a good fallback interface for, say, mobile browsers. Maybe a pseudo-listbox with radio buttons next to each item? The master list of items will in general be very long - over 100 items, certainly, possibly many more. Any given category will most likely contain one or two selected items, but the possibility exists for a category to have dozens of selected items, or zero selected items. As far as OS and stuff, the site is in classic asp (quit snickering!), the server-side code is VBScript, and so far we've avoided the various Javascript libraries by the simple expedient of almost never using client-side scripting. This one form for this one client is currently the big exception. Give 'em an inch and they want a mile... Oh, and I have to add: I suck at Javascript, or really at any C-descendant language. Curly braces give me hives. I'd really, really like something I can just copy & paste into my page, maybe tweak some variable names, and never look at it again. A girl can dream, can't she? :)

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c# - How do you get a variable's name as it was physically typed in its declaration?

- by Petras

The class below contains the field city. I need to dynamically determine the field's name as it is typed in the class declaration i.e. I need to get the string "city" from an instance of the object city. I have tried to do this by examining its Type in DoSomething() but can't find it when examining the contents of the Type in the debugger. Is it possible? public class Person { public string city = "New York"; public Person() { } public void DoSomething() { Type t = city.GetType(); string field_name = t.SomeUnkownFunction(); //would return the string "city" if it existed! } } Some people in their answers below have asked me why I want to do this. Here's why. In my real world situation, there is a custom attribute above city. [MyCustomAttribute("param1", "param2", etc)] public string city = "New York"; I need this attribute in other code. To get the attribute, I use reflection. And in the reflection code I need to type the string "city" MyCustomAttribute attr; Type t = typeof(Person); foreach (FieldInfo field in t.GetFields()) { if (field.Name == "city") { //do stuff when we find the field that has the attribute we need } } Now this isn't type safe. If I changed the variable "city" to "workCity" in my field declaration in Person this line would fail unless I knew to update the string if (field.Name == "workCity") //I have to make this change in another file for this to still work, yuk! { } So I am trying to find some way to pass the string to this code without physically typing it. Yes, I could declare it as a string constant in Person (or something like that) but that would still be typing it twice. Phew! That was tough to explain!! Thanks Thanks to all who answered this * a lot*. It sent me on a new path to better understand lambda expressions. And it created a new question.

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Powershell $LastExitCode=0 but $?=False . Redirecting stderr to stdout gives NativeCommandError

- by Colonel Panic

Can anyone explain Powershell's surprising behaviour in the second example below? First, a example of sane behaviour: PS C:\> & cmd /c "echo Hello from standard error 1>&2"; echo "`$LastExitCode=$LastExitCode and `$?=$?" Hello from standard error $LastExitCode=0 and $?=True No surprises. I print a message to standard error (using cmd's echo). I inspect the variables $? and $LastExitCode. They equal to True and 0 respectively, as expected. However, if I ask Powershell to redirect standard error to standard output over the first command, I get a NativeCommandError: PS C:\> & cmd /c "echo Hello from standard error 1>&2" 2>&1; echo "`$LastExitCode=$LastExitCode and `$?=$?" cmd.exe : Hello from standard error At line:1 char:4 + cmd <<<< /c "echo Hello from standard error 1>&2" 2>&1; echo "`$LastExitCode=$LastExitCode and `$?=$?" + CategoryInfo : NotSpecified: (Hello from standard error :String) [], RemoteException + FullyQualifiedErrorId : NativeCommandError $LastExitCode=0 and $?=False My first question, why the NativeCommandError ? Secondly, why is $? False when cmd ran successfully and $LastExitCode is 0? Powershell's docs about_Automatic_Variables don't explicitly define $?. I always supposed it is True if and only if $LastExitCode is 0 but my example contradicts that. Here's how I came across this behaviour in the real-world (simplified). It really is FUBAR. I was calling one Powershell script from another. The inner script: cmd /c "echo Hello from standard error 1>&2" if (! $?) { echo "Job failed. Sending email.." exit 1 } # do something else Running this simply .\job.ps1, it works fine, no email is sent. However, I was calling it from another Powershell script, logging to a file .\job.ps1 2>&1 > log.txt. In this case, an email is sent! Here, the act of observing a phenomenon changes its outcome. This feels like quantum physics rather than scripting! [Interestingly: .\job.ps1 2>&1 may or not blow up depending on where you run it]

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Container item implementation

- by onurozcelik

Hi, I am working in Train Traffic Controller software project. My responsibility in this project is to develop the visual railroad GUI. We are implementing the project with Qt. By now I am using QGraphicsLinearLayout to hold my items. I am using the layout because I do not want to calculate coordinates of each item. So far I wrote item classes to add the layout. For instance SwitchItem class symbolizes railroad switch in real world. Each item class is responsible for its own painting and events. So far so good. Now I need a composite item that can contain two or more item. This class is going to be responsible for painting the items contained in it. I need this class because I have to put two or more items inside same layout cell. If I don' t put them in same cell I can' t use layout. See the image below. BlockSegmentItem and SignalItem inside same cell. Here is my compositeitem implementation. #include "compositeitem.h" CompositeItem::CompositeItem(QString id,QList<FieldItem *> _children) { children = _children; } CompositeItem::~CompositeItem() { } QRectF CompositeItem::boundingRect() const { FieldItem *child; QRectF rect(0,0,0,0); foreach(child,children) { rect = rect.united(child->boundingRect()); } return rect; } void CompositeItem::paint(QPainter *painter, const QStyleOptionGraphicsItem *option, QWidget *widget ) { FieldItem *child; foreach(child,children) { child->paint(painter,option,widget); } } QSizeF CompositeItem::sizeHint(Qt::SizeHint which, const QSizeF &constraint) const { QSizeF itsSize(0,0); FieldItem *child; foreach(child,children) { // if its size empty set first child size to itsSize if(itsSize.isEmpty()) itsSize = child->sizeHint(Qt::PreferredSize); else { QSizeF childSize = child->sizeHint(Qt::PreferredSize); if(itsSize.width() < childSize.width()) itsSize.setWidth(childSize.width()); itsSize.setHeight(itsSize.height() + childSize.height()); } } return itsSize; } void CompositeItem::contextMenuEvent(QGraphicsSceneContextMenuEvent *event) { qDebug()<<"Test"; } This code works good with painting but when it comes to item events it is problematic. QGraphicsScene treats the composite item like a single item which is right for layout but not for events. Because each item has its own event implementation.(e.g. SignalItem has its special context menu event.) I have to handle item events seperately. Also I need a composite item implementation for the layout. How can I overcome this dilemma?

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Input string was not in the correct format using int.Parse

- by JDWebs

I have recently been making a login 'representation' which is not secure. So before answering, please note I am aware of security risks etc., and this will not be on a live site. Also note I am a beginner :P. For my login representation, I am using LINQ to compare values of a DDL to select a username and a Textbox to enter a password, when a login button is clicked. However, an error is thrown 'Input string was not in the correct format', when using int.Parse. Front End: <%@ Page Language="C#" AutoEventWireup="true" CodeFile="Login_Test.aspx.cs" Inherits="Login_Login_Test" %> <!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd"> <html xmlns="http://www.w3.org/1999/xhtml"> <head runat="server"> <title>Login Test</title> </head> <body> <form id="LoginTest" runat="server"> <div> <asp:DropDownList ID="DDL_Username" runat="server" Height="20px" DataTextField="txt"> </asp:DropDownList> <br /> <asp:TextBox ID="TB_Password" runat="server" TextMode="Password"></asp:TextBox> <br /> <asp:Button ID="B_Login" runat="server" onclick="B_Login_Click" Text="Login" /> <br /> <asp:Literal ID="LI_Result" runat="server"></asp:Literal> </div> </form> </body> </html> Back End: using System; using System.Collections.Generic; using System.Linq; using System.Web; using System.Web.UI; using System.Web.UI.WebControls; public partial class Login_Login_Test : System.Web.UI.Page { protected void Page_Load(object sender, EventArgs e) { if (!Page.IsPostBack) { Binder(); } } private void Binder() { using (DataClassesDataContext db = new DataClassesDataContext()) { DDL_Username.DataSource = from x in db.DT_Honeys select new { id = x.UsernameID, txt = x.Username }; DDL_Username.DataValueField = "id"; DDL_Username.DataTextField = "txt"; DDL_Username.DataBind(); } } protected void B_Login_Click(object sender, EventArgs e) { if (TB_Password.Text != "") { using (DataClassesDataContext db = new DataClassesDataContext()) { DT_Honey blah = new DT_Honey(); blah = db.DT_Honeys.SingleOrDefault(x => x.UsernameID == int.Parse(DDL_Username.SelectedValue.ToString())); if (blah == null) { LI_Result.Text = "Something went wrong :/"; } if (blah.Password == TB_Password.Text) { LI_Result.Text = "Credentials recognised :-)"; } else { LI_Result.Text = "Error with credentials :-("; } } } } } I am aware this problem is very common, but none of the help I have found online is useful/relevant. Any help/suggestions appreciated; thank you for your time :-).

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Time required for a process to complete

- by yelkawar

I am new to C# world. I am attempting to calculate time taken by a algorithum for the purpose of comparison. Following code measures the elapsed time from when a subroutine is called until the subroutine returns to the main program.This example is taken from "Data structures through C#" by Michael McMillan. After running this program the output is Time=0, which is incorrect. The program appears to be logically correct. Can anybody help me. Following is the code using System.Collections.Generic; using System.Collections; using System.Linq; using System.Text; namespace Chap1 { class Program { static void Main(string[] args) { int num1 = 100; int num2 = 200; Console.WriteLine("num1: " + num1); Console.WriteLine("num2: " + num2); Swap<int>(ref num1, ref num2); Console.WriteLine("num1: " + num1); Console.WriteLine("num2: " + num2); string str1 = "Sam"; string str2 = "Tom"; Console.WriteLine("String 1: " + str1); Console.WriteLine("String 2: " + str2); Swap<string>(ref str1, ref str2); Console.WriteLine("String 1: " + str1); Console.WriteLine("String 2: " + str2); Console.ReadKey(); } static void Swap<T>(ref T val1, ref T val2) { T temp; temp = val1; val1 = val2; val2 = temp; } } class Timing { TimeSpan StartTiming; TimeSpan duration; public Timing() { StartTiming = new TimeSpan(0); duration = new TimeSpan(0); } public TimeSpan startTime() { GC.Collect(); GC.WaitForPendingFinalizers(); StartTiming = Process.GetCurrentProcess().Threads[0].UserProcessorTime; return StartTiming; } public void stopTime() { duration = Process.GetCurrentProcess().Threads[0].UserProcessorTime.Subtract(StartTiming); } public TimeSpan result() { return duration; } } }

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Peer did not return a certificate

- by pfista

I am trying to get two way SSL authentication working between a Python server and an Android client application. I have access to both the server and client, and would like to implement client authentication using my own certificate. So far I have been able to verify the server certificate and connect without client authentication. What sort of certificate does the client need and how do I get it to automatically send it to the server during the handshake process? Here is the client and server side code that I have so far. Is my approach wrong? Server Code while True: # Keep listening for clients c, fromaddr = sock.accept() ssl_sock = ssl.wrap_socket(c, keyfile = "serverPrivateKey.pem", certfile = "servercert.pem", server_side = True, # Require the client to provide a certificate cert_reqs = ssl.CERT_REQUIRED, ssl_version = ssl.PROTOCOL_TLSv1, ca_certs = "clientcert.pem", #TODO must point to a file of CA certificates?? do_handshake_on_connect = True, ciphers="!NULL:!EXPORT:AES256-SHA") print ssl_sock.cipher() thrd = sock_thread(ssl_sock) thrd.daemon = True thrd.start() I suspect I may be using the wrong file for ca_certs...? Client Code private boolean connect() { try { KeyStore keystore = KeyStore.getInstance("BKS"); // Stores the client certificate, to be sent to server KeyStore truststore = KeyStore.getInstance("BKS"); // Stores the server certificate we want to trust // TODO: change hard coded password... THIS IS REAL BAD MKAY truststore.load(mSocketService.getResources().openRawResource(R.raw.truststore), "test".toCharArray()); keystore.load(mSocketService.getResources().openRawResource(R.raw.keystore), "test".toCharArray()); // Use the key manager for client authentication. Keys in the key manager will be sent to the host KeyManagerFactory keyFManager = KeyManagerFactory.getInstance(KeyManagerFactory.getDefaultAlgorithm()); keyFManager.init(keystore, "test".toCharArray()); // Use the trust manager to determine if the host I am connecting to is a trusted host TrustManagerFactory trustMFactory = TrustManagerFactory.getInstance(TrustManagerFactory .getDefaultAlgorithm()); trustMFactory.init(truststore); // Create the socket factory and add both the trust manager and key manager SSLCertificateSocketFactory socketFactory = (SSLCertificateSocketFactory) SSLCertificateSocketFactory .getDefault(5000, new SSLSessionCache(mSocketService)); socketFactory.setTrustManagers(trustMFactory.getTrustManagers()); socketFactory.setKeyManagers(keyFManager.getKeyManagers()); // Open SSL socket directly to host, host name verification is NOT performed here due to // SSLCertificateFactory implementation mSSLSocket = (SSLSocket) socketFactory.createSocket(mHostname, mPort); mSSLSocket.setSoTimeout(TIMEOUT); // Most SSLSocketFactory implementations do not verify the server's identity, allowing man-in-the-middle // attacks. This implementation (SSLCertificateSocketFactory) does check the server's certificate hostname, // but only for createSocket variants that specify a hostname. When using methods that use InetAddress or // which return an unconnected socket, you MUST verify the server's identity yourself to ensure a secure // connection. verifyHostname(); // Safe to proceed with socket now ... I have generated a client private key, a client certificate, a server private key, and a server certificate using openssl. I then added the client certificate to keystore.bks (which I store in /res/raw/keystore.bks) I then added the server certificate to the truststore.bks So now when the client tries to connect I am getting this error server side: ssl.SSLError: [Errno 1] _ssl.c:504: error:140890C7:SSL routines:SSL3_GET_CLIENT_CERTIFICATE:peer did not return a certificate And when I try to do this in the android client SSLSession s = mSSLSocket.getSession(); s.getPeerCertificates(); I get this error: javax.net.ssl.SSLPeerUnverifiedException: No peer certificate So obviously the keystore I am using doesn't appear to have a correct peer certificate in it and thus isn't sending one to the server. What should I put in the keystore to prevent this exception? Furthermore, is this method of two way SSL authentication safe and effective?

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should I ever put a major version number into a C#/Java namespace?

- by Andrew Patterson

I am designing a set of 'service' layer objects (data objects and interface definitions) for a WCF web service (that will be consumed by third party clients i.e. not in-house, so outside my direct control). I know that I am not going to get the interface definition exactly right - and am wanting to prepare for the time when I know that I will have to introduce a breaking set of new data objects. However, the reality of the world I am in is that I will also need to run my first version simultaneously for quite a while. The first version of my service will have URL of http://host/app/v1service.svc and when the times comes by new version will live at http://host/app/v2service.svc However, when it comes to the data objects and interfaces, I am toying with putting the 'major' version of the interface number into the actual namespace of the classes. namespace Company.Product.V1 { [DataContract(Namespace = "company-product-v1")] public class Widget { [DataMember] string widgetName; } public interface IFunction { Widget GetWidgetData(int code); } } When the time comes for a fundamental change to the service, I will introduce some classes like namespace Company.Product.V2 { [DataContract(Namespace = "company-product-v2")] public class Widget { [DataMember] int widgetCode; [DataMember] int widgetExpiry; } public interface IFunction { Widget GetWidgetData(int code); } } The advantages as I see it are that I will be able to have a single set of code serving both interface versions, sharing functionality where possible. This is because I will be able to reference both interface versions as a distinct set of C# objects. Similarly, clients may use both interface versions simultaneously, perhaps using V1.Widget in some legacy code whilst new bits move on to V2.Widget. Can anyone tell why this is a stupid idea? I have a nagging feeling that this is a bit smelly.. notes: I am obviously not proposing every single new version of the service would be in a new namespace. Presumably I will do as many non-breaking interface changes as possible, but I know that I will hit a point where all the data modelling will probably need a significant rewrite. I understand assembly versioning etc but I think this question is tangential to that type of versioning. But I could be wrong.

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How do I get through proxy server environments for non-standard services?

- by Ripred

I'm not real hip on exactly what role(s) today's proxy servers can play and I'm learning so go easy on me :-) I have a client/server system I have written using a homegrown protocol and need to enhance the client side to negotiate its way out of a proxy environment. I have an existing client and server system written in C and C++ for the speed and a small amount of MFC in the client to handle the user interface. I have written both the server and client side of the system on Windows (the people I work for are mainly web developers using Windows everything - not a choice) sticking to Berkeley Sockets as it were via wsock32 for efficiency. The clients connect to the server through a nonstandard port (even though using port 80 is an option to get out of some environments but the protocol that goes over it isn't HTTP). The TCP connection(s) stay open for the duration of the clients participation in real time conferences. Our customer base is expanding to all kinds of networked environments. I have been able to solve a lot of problems by adding the ability to connect securely over port 443 and using secure sockets which allows the protocol to pass through a lot environments since the internal packets can't be sniffed. But more and more of our customers are behind a proxy server environment and my direct connections don't make it through. My old school understanding of proxy servers is that they act as a proxy for external HTML content over HTTP, possibly locally caching popular material for faster local access, and also allowing their IT staff to blacklist certain destination sites. Customer are complaining that my software doesn't recognize and easily navigate its way through their proxy environments but I'm finding it difficult to decide what my "best fit" solution should be. My software doesn't tear down the connection after each client request, and on top of that packets can come from either side at any time, basically your typical custom client/server system for a specific niche. My first reaction is "why can't they just add my servers addresses to their white list" but if there is a programmatic way I can get through without requiring their IT staff to help it is politically better and arguably a better solution anyway. Plus maybe I'm still not understanding the role and purpose of what proxy servers and environments have grown to be these days. My first attempt at a solution was to use WinInet with its various proxy capabilities to establish a connection over port 80 to my non-standard protocol server (which knows enough to recognize and answer a simple HTTP-looking GET request and answer it with a simple HTTP response page to get around some environments that employ initial packet sniffing (DPI)). I retrieved the actual SOCKET handle behind WinInet's HINTERNET request object and had hoped to use that in place of my software's existing SOCKET connection and hopefully not need to change much more on the client side. It initially seemed to be my solution but on further inspection it seems that the OS gets first-chance at the received data on this socket since when I get notified of events via the standard select(...) statement on the socket and query the size of the data available via ioctlsocket the call succeeds but returns 0 bytes available, the reads don't work and it goes downhill from there. Can someone tell me of a client-side library (commercial is fine) will let me get past these proxy server environments with as little user and IT staff help as possible? From what I read it has grown past SOCKS and I figure someone has to have solved this problem before me. Thanks for reading my long-winded question, Ripred

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Best method for converting several sets of numbers with several different ratios

- by C Patton

I'm working on an open-source harm reduction application for opioid addicts. One of the features in this application is the conversion (in mg/mcg) between common opioids, so people don't overdose by accident. If you're morally against opioid addiction and wouldn't respond because of your morals, please consider that this application is for HARM REDUCTION.. So people don't end up dead. I have this data.. 3mg morphine IV = 10mcg fentanyl IV 2mg morphine oral = 1mg oxycodone oral 3mg oral morphine = 1mg oxymorphone oral 7.0mg morphine oral = 1mg hydromorphone oral 1mg morphine iv = .10mg oxymorphone iv 1mg morphine oral = 1mg hydrocodone oral 1mg morphine oral = 6.67mg codeine oral 1mg morphine oral = .10mg methadone oral And I have a textbox that is the source dosage in mg (a double) that the user can enter in. Underneath this, I have radio boxes for the source substance (ie: morphine) and the destination substance (ie oxycodone) for conversion.. I've been trying to think of the most efficient way to do this, but nearly every seems sloppy. If I were to do something like public static double MorphinetoOxycodone(string morphineValue) { double morphine = Double.Parse(morphineValue); return (morphine / 2 ); } I would also have to make a function for OxycodonetoMorphine, OxycodonetoCodeine, etc.. and then would end up with dozens functions.. There must be an easier way than this that I'm missing. If you'll notice, all of my conversions use morphine as the base value.. what might be the easiest way to use the morphine value to convert one opioid to another? For example, if 1mg morphine oral is equal to 1mg hydrocodone and 1mg morphine oral is equal to .10mg methadone, wouldn't I just multiply 1*.10 to get the hydrocodone-methadone value? Implementing this idea is what I'm having the most trouble with. Any help would be GREATLY appreciated.. and if you'd like, I would add your name/nickname to the credits in this program. It's possible that many, many people around the world will use this (I'm translating it into several languages as well) and to know that your work could've helped an addict from dying.. I think that's a great thing :) -cory

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Design Technique: How to design a complex system for processing orders, products and units.

- by Shyam

Hi, Programming is fun: I learned that by trying out simple challenges, reading up some books and following some tutorials. I am able to grasp the concepts of writing with OO (I do so in Ruby), and write a bit of code myself. What bugs me though is that I feel re-inventing the wheel: I haven't followed an education or found a book (a free one that is) that explains me the why's instead of the how's, and I've learned from the A-team that it is the plan that makes it come together. So, armed with my nuby Ruby skills, I decided I wanted to program a virtual store. I figured out the following: My virtual Store will have: Products and Services Inventories Orders and Shipping Customers Now this isn't complex at all. With the help of some cool tools (CMapTools), I drew out some concepts, but quickly enough (thanks to my inferior experience in designing), my design started to bite me. My very first product-line were virtual "laptops". So, I created a class (Ruby): class Product attr_accessor :name, :price def initialize(name, price) @name = name @price = price end end which can be instantiated by doing (IRb) x = Product.new("Banana Pro", 250) Since I want my virtual customers to be able to purchase more than one product, or various types, I figured out I needed some kind of "Order" mechanism. class Order def initialize(order_no) @order_no = order_no @line_items = [] end def add_product(myproduct) @line_items << myproduct end def show_order() puts @order_no @line_items.each do |x| puts x.name.to_s + "\t" + x.price.to_s end end end that can be instantiated by doing (IRb) z = Order.new(1234) z.add_product(x) z.show_order Splendid, I have now a very simple ordering system that allows me to add products to an order. But, here comes my real question. What if I have three models of my product (economy, business, showoff)? Or have my products be composed out of separate units (bigger screen, nicer keyboard, different OS)? Surely I could make them three separate products, or add complexity to my product class, but I am looking for are best practices to design a flexible product object that can be used in the real world, to facilitate a complex system. My apologies if my grammar and my spelling are with error, as english is not my first language and I took the time to check as far I could understand and translate properly! Thank you for your answers, comments and feedback!

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