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  • how close a connection from server side that created by ajax from client side

    - by saeid
    I have this sample php code: <?php function response($a) { @ob_end_clean(); header("Connection: close"); ob_start(); echo $a; $length = ob_get_length(); header("Content-Length: $length"); ob_end_flush(); flush(); } response("test1"); sleep(5); echo "test2"; ?> now I make a connection to server from client by ajax. now I want to server only send "test1" to me and then close the connection. but connection not closed and wait 5 seconds and send me "test1 test2" !! this is response headers from server to me : X-Powered-By: PHP/5.3.27 Connection: close Vary: Accept-Encoding,User-Agent Content-Encoding: gzip Cache-Control: private, no-cache, no-store, ------revalidate, no-transform Transfer-Encoding: chunked Content-Type: text/html in response headers I do not see Content-Length header. is problem for this ?? or if not what I must do now for solving problem ??

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  • Click at specified client area

    - by VixinG
    Click doesn't work - I don't know why and can't find a solution :( ie. Click(150,215) should move mouse to the client area and click there. [DllImport("user32.dll")] private static extern bool ScreenToClient(IntPtr hWnd, ref Point lpPoint); [DllImport("user32", SetLastError = true)] private static extern int SetCursorPos(int x, int y); static void MouseMove(int x, int y) { Point p = new Point(x * -1, y * -1); ScreenToClient(hWnd, ref p); p = new Point(p.X * -1, p.Y * -1); SetCursorPos(p.X, p.Y); } static void Click(int x, int y) { MouseMove(x, y); SendMessage(hWnd, WM_LBUTTONDOWN, (IntPtr)0x1, new IntPtr(y * 0x10000 + x)); SendMessage(hWnd, WM_LBUTTONUP, (IntPtr)0x1, new IntPtr(y * 0x10000 + x)); } Edit: Of course I can use mouse_event for that, but I would like to see a solution for SendMessage()... [DllImport("user32.dll")] static extern void mouse_event(int dwFlags, int dx, int dy, int dwData, int dwExtraInfo); const int LEFTDOWN = 0x00000002; const int LEFTUP = 0x00000004; static void Click(int x, int y) { MouseMove(x, y); mouse_event((int)(LEFTDOWN), 0, 0, 0, 0); mouse_event((int)(LEFTUP), 0, 0, 0, 0); }

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  • Client-side user custom CSS single file for overriding multiple domains

    - by Cawas
    This is for using in Safari, though it could probably be used on Firefox as well. In Chrome you have to add a plugin anyway (which generally allow for custom CSS per domain), and Opera already allows this to be done without needing any CSS. But while it's for customizing on the client-side, it's also a pure CSS question. So I'm using no plugins here. So, again, I got a custom CSS code (easily) working for all domains. Now I want to get specify CSS code for each domain. All with just 1 CSS file that's being loaded by Safari. Over the web and googling, I've found two ways to supposedly do this, but none actually worked. They're both documented on userstyles.com: @-moz-document domain("your-domain.com") { }. This would be perfect, since I can have several tags like that and just choose which style will be loaded for which domain. It just doesn't work. @namespace is quite confusing and I've tried every variation I could think of. None worked.

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  • mod_rewrite settings causes server to throw HTTP 500 errors instead of 404

    - by FractalizeR
    Hello. I have a server with VBulletin forum (working under Apache 2.2, CentOS). The default settings for it in .htaccess are as follows: RewriteEngine on RewriteCond %{HTTP_HOST} ^gsmforum\.ru RewriteRule (.*) http://www.gsmforum.ru/$1 [R=301,L] # If you are having problems or are using VirtualDocumentRoot, uncomment this line and set it to your vBulletin directory. RewriteBase / RewriteCond %{REQUEST_FILENAME} -s [OR] RewriteCond %{REQUEST_FILENAME} -l [OR] RewriteCond %{REQUEST_FILENAME} -d RewriteRule ^.*$ - [NC,L] # Forum RewriteRule ^threads/.* showthread.php [QSA] RewriteRule ^forums/.* forumdisplay.php [QSA] RewriteRule ^members/.* member.php [QSA] RewriteRule ^blogs/.* blog.php [QSA] ReWriteRule ^entries/.* entry.php [QSA] RewriteCond %{REQUEST_FILENAME} -s [OR] RewriteCond %{REQUEST_FILENAME} -l [OR] RewriteCond %{REQUEST_FILENAME} -d RewriteRule ^.*$ - [NC,L] # MVC RewriteRule ^(?:(.*?)(?:/|$))(.*|$)$ $1.php?r=$2 [QSA] If I try to access any non-existent URL on forum like www.example.com/ajdsjaskasajs, server throws HTTP 500 error. Apache log says: [Sun Apr 25 17:24:32 2010] [error] [client 82.211.152.12] Request exceeded the limit of 10 internal redirects due to probable configuration error. Use 'LimitInternalRecursion' to increase the limit if necessary. Use 'LogLevel debug' to get a backtrace., referer: http://www.gsmforum.ru/forumdisplay.php?424-%CD%EE%E2%EE%F1%F2%E8-%EF%F0%EE%E3%F0%E0%EC%EC%E0%F2%EE%F0%EE%E2 If I switch LogLevel to Debug I get something like this: [Sun Apr 25 17:30:46 2010] [debug] core.c(3059): [client 95.25.70.85] redirected from r->uri = /robots.txt.php.php.php.php.php.php.php.php.php [Sun Apr 25 17:30:46 2010] [debug] core.c(3059): [client 95.25.70.85] redirected from r->uri = /robots.txt.php.php.php.php.php.php.php.php [Sun Apr 25 17:30:46 2010] [debug] core.c(3059): [client 95.25.70.85] redirected from r->uri = /robots.txt.php.php.php.php.php.php.php [Sun Apr 25 17:30:46 2010] [debug] core.c(3059): [client 95.25.70.85] redirected from r->uri = /robots.txt.php.php.php.php.php.php [Sun Apr 25 17:30:46 2010] [debug] core.c(3059): [client 95.25.70.85] redirected from r->uri = /robots.txt.php.php.php.php.php [Sun Apr 25 17:30:46 2010] [debug] core.c(3059): [client 95.25.70.85] redirected from r->uri = /robots.txt.php.php.php.php [Sun Apr 25 17:30:46 2010] [debug] core.c(3059): [client 95.25.70.85] redirected from r->uri = /robots.txt.php.php.php [Sun Apr 25 17:30:46 2010] [debug] core.c(3059): [client 95.25.70.85] redirected from r->uri = /robots.txt.php.php [Sun Apr 25 17:30:46 2010] [debug] core.c(3059): [client 95.25.70.85] redirected from r->uri = /robots.txt.php [Sun Apr 25 17:30:46 2010] [debug] core.c(3059): [client 95.25.70.85] redirected from r->uri = /robots.txt [root@server2 logs]# tail httpd_error.log [Sun Apr 25 17:31:27 2010] [debug] core.c(3059): [client 217.118.79.27] redirected from r->uri = /clientscript.php.php.php.php.php.php.php, referer: http://74.125.77.132/search?q=cache:bGPJ8XkSvlMJ:www.gsmforum.ru/showthread.php%3Ft%3D62479+%D0%A3%D0%BC%D0%B5%D0%BD%D1%8C%D1%88%D0%B5%D0%BD%D0%B8%D0%B5+%D0%BF%D0%B8%D0%BD%D0%B3%D0%B0+3G+%D0%BC%D0%BE%D0%B4%D0%B5%D0%BC&cd=3&hl=ru&ct=clnk&gl=ru [Sun Apr 25 17:31:27 2010] [debug] core.c(3059): [client 217.118.79.27] redirected from r->uri = /clientscript.php.php.php.php.php.php, referer: http://74.125.77.132/search?q=cache:bGPJ8XkSvlMJ:www.gsmforum.ru/showthread.php%3Ft%3D62479+%D0%A3%D0%BC%D0%B5%D0%BD%D1%8C%D1%88%D0%B5%D0%BD%D0%B8%D0%B5+%D0%BF%D0%B8%D0%BD%D0%B3%D0%B0+3G+%D0%BC%D0%BE%D0%B4%D0%B5%D0%BC&cd=3&hl=ru&ct=clnk&gl=ru [Sun Apr 25 17:31:27 2010] [debug] core.c(3059): [client 217.118.79.27] redirected from r->uri = /clientscript.php.php.php.php.php, referer: http://74.125.77.132/search?q=cache:bGPJ8XkSvlMJ:www.gsmforum.ru/showthread.php%3Ft%3D62479+%D0%A3%D0%BC%D0%B5%D0%BD%D1%8C%D1%88%D0%B5%D0%BD%D0%B8%D0%B5+%D0%BF%D0%B8%D0%BD%D0%B3%D0%B0+3G+%D0%BC%D0%BE%D0%B4%D0%B5%D0%BC&cd=3&hl=ru&ct=clnk&gl=ru [Sun Apr 25 17:31:27 2010] [debug] core.c(3059): [client 217.118.79.27] redirected from r->uri = /clientscript.php.php.php.php, referer: http://74.125.77.132/search?q=cache:bGPJ8XkSvlMJ:www.gsmforum.ru/showthread.php%3Ft%3D62479+%D0%A3%D0%BC%D0%B5%D0%BD%D1%8C%D1%88%D0%B5%D0%BD%D0%B8%D0%B5+%D0%BF%D0%B8%D0%BD%D0%B3%D0%B0+3G+%D0%BC%D0%BE%D0%B4%D0%B5%D0%BC&cd=3&hl=ru&ct=clnk&gl=ru [Sun Apr 25 17:31:27 2010] [debug] core.c(3059): [client 217.118.79.27] redirected from r->uri = /clientscript.php.php.php, referer: http://74.125.77.132/search?q=cache:bGPJ8XkSvlMJ:www.gsmforum.ru/showthread.php%3Ft%3D62479+%D0%A3%D0%BC%D0%B5%D0%BD%D1%8C%D1%88%D0%B5%D0%BD%D0%B8%D0%B5+%D0%BF%D0%B8%D0%BD%D0%B3%D0%B0+3G+%D0%BC%D0%BE%D0%B4%D0%B5%D0%BC&cd=3&hl=ru&ct=clnk&gl=ru [Sun Apr 25 17:31:27 2010] [debug] core.c(3059): [client 217.118.79.27] redirected from r->uri = /clientscript.php.php, referer: http://74.125.77.132/search?q=cache:bGPJ8XkSvlMJ:www.gsmforum.ru/showthread.php%3Ft%3D62479+%D0%A3%D0%BC%D0%B5%D0%BD%D1%8C%D1%88%D0%B5%D0%BD%D0%B8%D0%B5+%D0%BF%D0%B8%D0%BD%D0%B3%D0%B0+3G+%D0%BC%D0%BE%D0%B4%D0%B5%D0%BC&cd=3&hl=ru&ct=clnk&gl=ru [Sun Apr 25 17:31:27 2010] [debug] core.c(3059): [client 217.118.79.27] redirected from r->uri = /clientscript.php, referer: http://74.125.77.132/search?q=cache:bGPJ8XkSvlMJ:www.gsmforum.ru/showthread.php%3Ft%3D62479+%D0%A3%D0%BC%D0%B5%D0%BD%D1%8C%D1%88%D0%B5%D0%BD%D0%B8%D0%B5+%D0%BF%D0%B8%D0%BD%D0%B3%D0%B0+3G+%D0%BC%D0%BE%D0%B4%D0%B5%D0%BC&cd=3&hl=ru&ct=clnk&gl=ru [Sun Apr 25 17:31:27 2010] [debug] core.c(3059): [client 217.118.79.27] redirected from r->uri = /clientscript/vbulletin_css/style-d95b06dc-00001.css, referer: http://74.125.77.132/search?q=cache:bGPJ8XkSvlMJ:www.gsmforum.ru/showthread.php%3Ft%3D62479+%D0%A3%D0%BC%D0%B5%D0%BD%D1%8C%D1%88%D0%B5%D0%BD%D0%B8%D0%B5+%D0%BF%D0%B8%D0%BD%D0%B3%D0%B0+3G+%D0%BC%D0%BE%D0%B4%D0%B5%D0%BC&cd=3&hl=ru&ct=clnk&gl=ru If I remove or comment the last (#MVC) line from .htaccess all is fine. Can you advise me what is the problem with mod_rewrite settings? Why does the last line cause infinite recursion?

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  • HTTPS Redirect Causing Error "Server cannot append header after HTTP headers have been sent"

    - by Chad
    I need to check that our visitors are using HTTPS. In BasePage I check if the request is coming via HTTPS. If it's not, I redirect back with HTTPS. However, when someone comes to the site and this function is used, I get the error: System.Web.HttpException: Server cannot append header after HTTP headers have been sent. at System.Web.HttpResponse.AppendHeader(String name, String value) at System.Web.HttpResponse.AddHeader(String name, String value) at Premier.Payment.Website.Generic.BasePage..ctor() Here is the code I started with: // If page not currently SSL if (HttpContext.Current.Request.ServerVariables["HTTPS"].Equals("off")) { // If SSL is required if (GetConfigSetting("SSLRequired").ToUpper().Equals("TRUE")) { string redi = "https://" + HttpContext.Current.Request.ServerVariables["SERVER_NAME"].ToString() + HttpContext.Current.Request.ServerVariables["SCRIPT_NAME"].ToString() + "?" + HttpContext.Current.Request.ServerVariables["QUERY_STRING"].ToString(); HttpContext.Current.Response.Redirect(redi.ToString()); } } I also tried adding this above it (a bit I used in another site for a similar problem): // Wait until page is copletely loaded before sending anything since we re-build HttpContext.Current.Response.BufferOutput = true; I am using c# in .NET 3.5 on IIS 6. enter code here

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  • what can be causes of http server crash?

    - by mithunmo
    Hello , I am using WAMP server on Windows XP. - Apache 2.2.11 - MySQL 5.1.36 (INNODB engine) - PHP 5.3.0 I observe that my WAMP server crashes in the following scenarios 1) IF I use a Low end PC ( low processor speed and low RAM) 2) After making some changes to httpd.conf file .For eg changing the Allow from IP address . But here it crashes only once and then it starts to work fine. 3) Random crashes CRASH LOG szAppName : httpd.exe szAppVer : 2.2.11.0 szModName : php5ts.dll szModVer : 5.3.0.0 offset : 0000c309 C:\DOCUME~1\blrcom\LOCALS~1\Temp\WERc677.dir00\httpd.exe.mdmp C:\DOCUME~1\blrcom\LOCALS~1\Temp\WERc677.dir00\appcompat.txt My questions 1) Does high CPU utilization/LOW RAM can also cause the HTTP server to crash ? 2) excessive file reading as in every 10 seconds ? 3) unlimited script execution time . I have set the maximum execution time in php script to 0 as my script has to execute for sometimes 2-3 days. Is there any way to avoid this ? 4) Access to Database ? Should we use lock before reading and writing Can these be the reasons for random wamp server crashes ? OR is is some other programming error ? Please guide me . Regards, Mithun

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  • Http Requests POST vs GET

    - by behrk2
    Hi everyone, I am using a lot of HTTP Requests in an application that I am writing which uses OAuth. Currently, I am sending my GET and POST requests the same way: HttpConnection connection = (HttpConnection) Connector.open(url + connectionParameters); connection.setRequestMethod(method); connection.setRequestProperty("WWW-Authenticate", "OAuth realm=api.netflix.com"); int responseCode = connection.getResponseCode(); And this is working fine. I am successfully POSTing and GETing. However, I am worried that I am not doing POST the right way. Do I need to include in the above code the following if-statement? if (method.equals("POST") && postData != null) { connection.setRequestProperty("Content-type", "application/x-www-form-urlencoded"); connection.setRequestProperty("Content-Length", Integer .toString(postData.length)); OutputStream requestOutput = connection.openOutputStream(); requestOutput.write(postData); requestOutput.close(); } If so, why? What's the difference? I would appreciate any feedback. Thanks!

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  • Java HTTP Requests Buffer size

    - by behrk2
    Hello, I have an HTTP Request Dispatcher class that works most of the time, but I had noticed that it "stalls" when receiving larger requests. After looking into the problem, I thought that perhaps I wasn't allocating enough bytes to the buffer. Before, I was doing: byte[] buffer = new byte[10000]; After changing it to 20000, it seems to have stopped stalling: String contentType = connection.getHeaderField("Content-type"); ByteArrayOutputStream baos = new ByteArrayOutputStream(); InputStream responseData = connection.openInputStream(); byte[] buffer = new byte[20000]; int bytesRead = responseData.read(buffer); while (bytesRead > 0) { baos.write(buffer, 0, bytesRead); bytesRead = responseData.read(buffer); } baos.close(); connection.close(); Am I doing this right? Is there anyway that I can dynamically set the number of bytes for the buffer based on the size of the request? Thanks...

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  • Sharing session variables from http and https versio

    - by tangurena
    I am trying to fix an ASP.NET site that a friend had botched converting from older technologies. To the user, the site appears to have public and secured sections. Behind the scenes, the public and private sites are separate web applications with separate app pools. The difficulty arises because it appears that the applications share the same session IDs (when going from the public to the secured pages, the session ID remains the same), yet none of the (InProc) session variables are getting passed from the public site to the private one. Basically, the workflow consists of the user checking a checkbox ("I agree" type of stuff) on the public site (let's call that page http://www.boring.gov/iAgree.aspx), then logging in on the secured site (let's call that page https://www.boring.gov/login.aspx). The commandments from the parent agency in DC are that the user may not bookmark the login page, the user has to click "I agree" every time they log in, and that the "I agree" stuff has to be on a separate page. What am I missing? How would you do it? Notes: 1 - This is getting hosted on a single Windows 2003 server. 2 - Yes, it is a government agency. 3 - I would have done things very differently if I was doing the conversion, but I wasn't brought in until the poop hit the fan, and it is too late to redo things. 4 - Two previous SO threads that appear to be related, yet don't apply are this and that

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  • Server crash = How does a TCP/IP (and the browser-client) behave after this?

    - by jens
    Hello Experts, i would be thankfull for an explanation what happens with HTTP(TCP/IP) transmissions when the server crashes unexpectedly, how does the client Browser (Firefox / IE) handle this event. What happens in the following two standard cases: Clients-actively sends data: The TCP/IP Connection has been estableshed and the Client (Web-Browser) is Sending a POST Request with some data and in the middle of the process of sending the server crashes. What does this mean for the client? As far as I know TCP/IP does not "acknowledge" a send data-package so the client does not know that the server crashed. How will the client behave? (Firefox and Internet Explorer)? The Server is actively sending data: As above the tcp/ip connection has been established and the Server is sending a large website to the client (browser). In the middle of the sending-process the server crashes, so no futher packets are sent. How does the client browser react to this event (Firefox and Interne Expolrer) Thank you very much!! Jens

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  • Passing array values in an HTTP request in .NET

    - by Zarjay
    What's the standard way of passing and processing an array in an HTTP request in .NET? I have a solution, but I don't know if it's the best approach. Here's my solution: <form action="myhandler.ashx" method="post"> <input type="checkbox" name="user" value="Aaron" /> <input type="checkbox" name="user" value="Bobby" /> <input type="checkbox" name="user" value="Jimmy" /> <input type="checkbox" name="user" value="Kelly" /> <input type="checkbox" name="user" value="Simon" /> <input type="checkbox" name="user" value="TJ" /> <input type="submit" value="Submit" /> </form> The ASHX handler receives the "user" parameter as a comma-delimited string. You can get the values easily by splitting the string: public void ProcessRequest(HttpContext context) { string[] users = context.Request.Form["user"].Split(','); } So, I already have an answer to my problem: assign multiple values to the same parameter name, assume the ASHX handler receives it as a comma-delimited string, and split the string. My question is whether or not this is how it's typically done in .NET. What's the standard practice for this? Is there a simpler way to grab the multiple values than assuming that the value is comma-delimited and calling Split() on it? Is this how arrays are typically passed in .NET, or is XML used instead? Does anyone have any insight on whether or not this is the best approach?

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  • How to handle building and parsing HTTP URL's / URI's / paths in Perl

    - by Robert S. Barnes
    I have a wget like script which downloads a page and then retrieves all the files linked in img tags on that page. Given the URL of the original page and the the link extracted from the img tag in that page I need to build the URL for the image file I want to retrieve. Currently I use a function I wrote: sub build_url { my ( $base, $path ) = @_; # if the path is absolute just prepend the domain to it if ($path =~ /^\//) { ($base) = $base =~ /^(?:http:\/\/)?(\w+(?:\.\w+)+)/; return "$base$path"; } my @base = split '/', $base; my @path = split '/', $path; # remove a trailing filename pop @base if $base =~ /[[:alnum:]]+\/[\w\d]+\.[\w]+$/; # check for relative paths my $relcount = $path =~ /(\.\.\/)/g; while ( $relcount-- ) { pop @base; shift @path; } return join '/', @base, @path; } The thing is, I'm surely not the first person solving this problem, and in fact it's such a general problem that I assume there must be some better, more standard way of dealing with it, using either a core module or something from CPAN - although via a core module is preferable. I was thinking about File::Spec but wasn't sure if it has all the functionality I would need.

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  • Forwarding HTTP Request with Direct Server Return

    - by Daniel Crabtree
    I have servers spread across several data centers, each storing different files. I want users to be able to access the files on all servers through a single domain and have the individual servers return the files directly to the users. The following shows a simple example: 1) The user's browser requests http://www.example.com/files/file1.zip 2) Request goes to server A, based on the DNS A record for example.com. 3) Server A analyzes the request and works out that /files/file1.zip is stored on server B. 4) Server A forwards the request to server B. 5) Server B returns file1.zip directly to the user without going through server A. Note: steps 4 and 5 must be transparent to the user and cannot involve sending a redirect to the user as that would violate the requirement of a single domain. From my research, what I want to achieve is called "Direct Server Return" and it is a common setup for load balancing. It is also sometimes called a half reverse proxy. For step 4, it sounds like I need to do MAC Address Translation and then pass the request back onto the network and for servers outside the network of server A tunneling will be required. For step 5, I simply need to configure server B, as per the real servers in a load balancing setup. Namely, server B should have server A's IP address on the loopback interface and it should not answer any ARP requests for that IP address. My problem is how to actually achieve step 4? I have found plenty of hardware and software that can do this for simple load balancing at layer 4, but these solutions fall short and cannot handle the kind of custom routing I require. It seems like I will need to roll my own solution. Ideally, I would like to do the routing / forwarding at the web server level, i.e. in PHP or C# / ASP.net. However, I am open to doing it at a lower level such as Apache or IIS, or at an even lower level, i.e. a custom proxy service in front of everything.

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  • Perl: Value of response code in HTTP::Request

    - by lola
    Hi all, So, I am writing a code to get a document from the internet. The document size is around 200 KB. This is the code: !/usr/local/bin/perl -w use strict; use LWP::UserAgent; my $ua = LWP::UserAgent->new; my $url = "SOME URL"; my $req = HTTP::Request->new(GET => $url); my $res = $ua->request($req); if($res->is_success){ print $res->content ."\n"; } else{ print "Error: " . $res->status_line; } Now, the only problem is I can't mention what the URL is. However, the output is: "Error: 500 read timeout". When I checked the link externally, the data is being downloaded in under 5 seconds. I even changed the timeout to 1000s, but it still didn't work. How should I go about finding more information related to the response. The size of the file (around 200KB) is also not too great to warrant a read timeout. The server is also not a busy one, didn't give a problem whenever I checked the link on the browser. Thanks.

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  • Sending an HTTP POST request through the android emulator doesn't work

    - by Sotirios Delimanolis
    I'm running a tomcat servlet on my local machine and an Android emulator with an app that makes a post request to the servlet. The code for the POST is below (without exceptions and the like): String strUrl = "http://10.0.2.2:8080/DeviceDiscoveryServer/server/devices/"; Device device = Device.getUniqueInstance(); urlParameters += URLEncoder.encode("user", "UTF-8") + "=" + URLEncoder.encode(device.getUser(), "UTF-8"); urlParameters += "&" + URLEncoder.encode("port", "UTF-8") + "=" + URLEncoder.encode(new Integer(Device.PORT).toString(), "UTF-8"); urlParameters += "&" + URLEncoder.encode("address", "UTF-8") + "=" + URLEncoder.encode(device.getAddress().getHostAddress(), "UTF-8"); URL url = new URL(strUrl); HttpURLConnection connection = (HttpURLConnection) url.openConnection(); connection.setDoOutput(true); connection.setRequestMethod("POST"); OutputStreamWriter wr = new OutputStreamWriter(connection.getOutputStream()); wr.write(urlParameters); wr.flush(); wr.close(); Whenever this code is executed, the servlet isn't called. However if I change the type of the request to 'GET' and don't write anything to the outputstream, the servlet gets called and everything works fine. Am I just not making the POST correctly or is there some other error?

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  • Write transparent HTTP Proxy script in PHP

    - by Leo Izen
    Is there an easy forwarding/transparent php proxy script that I can host on my web server? These are my conditions: I'm using free web hosting, so I have pretty much no control over my machine. Otherwise I could use Perl's HTTP::Proxy module. This means no root password. It does run php though. I already have a server running on port 80. What I mean is I would like to put a php script as index.php on my server that will forward all requests. I don't want a script like PHProxy or Glype where I go to the site, then enter a URL. I want a server so I can enter proxy.example.com:80 in Firefox's or IE's or whatever's proxy settings and it will forward all requests to the server. Preferably (though not fatal if not possible) I would like for it to pass on the USER_AGENT environmental variable (That's the browser) instead of setting itself to be the USER_AGENT I can't start a new Daemon. My server won't allow it. Is there a script that will do this? If so, which?

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  • Configuring Oracle HTTP Server 12c for WebLogic Server Domain

    - by Emin Askerov
    Oracle HTTP Server (OHS) 12c 12.1.2 which was released in July 2013 as a part of Oracle Web Tier 12c is the web server component of Oracle Fusion Middleware. In essence this is Apache HTTP Server 2.2.22 (with critical bug fixes from higher versions) which includes modules developed specifically by Oracle. It provides a listener functionality for Oracle WebLogic Server and the framework for hosting static pages, dynamic pages, and applications over the Web. OHS can be easily managed by Weblogic Management Framework, a set of tools which provides administrative capabilities (start, stop, lifecycle operations, etc.) for Oracle Fusion Middleware products. In other words all tools which are familiar to us (Node Manager, WLST, Administration Console, Fusion Middleware Control etc.) presented as a part of Weblogic Management Framework and using for managing Java and System Components both for Weblogic Server and Standalone Domain types. You can familiarize yourself with these terms using related documentation: 1. Introduction to Oracle HTTP Server: http://docs.oracle.com/middleware/1212/webtier/index.html 2. Weblogic Management Framework: http://docs.oracle.com/middleware/1212/core/ASCON/terminology.htm#ASCON11260 In the given post I would like to cover rather simple use case how to configure OHS as web proxy in Weblogic Cluster environment. For example, we have existing Weblogic Domain where some managed servers have been joined to cluster and host business applications. We need to configure web proxy component which will act as entry point, load balancer for our cluster for user requests. Of course, we could install old good Apache HTTP Server and configure mod_wl plugin. However this solution not optimal from manageability perspective: we need to install Apache, install additional plugin then configure it by editing configuration file which is not really convenient for FMW Administrators and often increase time of performing of simple administrative task. Alternatively, we could use OHS as System Component within Weblogic Domain and use full power of Weblogic Management Framework in order to configure, manage and monitor it! I like this idea! What about you? I hope after reading this post you will agree with me. First of all it is necessary to download OHS binaries. You can use this link for downloading: http://www.oracle.com/technetwork/java/webtier/downloads/index2-303202.html As we will use Fusion Middleware Control for managing OHS instances it is necessary to extend your domain with Enterprise Manager and Oracle ADF and JRF templates. This is not topic for focusing in this post, but you could get more information from documentation or one of my previous posts: http://docs.oracle.com/middleware/1212/wls/WLDTR/fmw_templates.htm#sthref64 https://blogs.oracle.com/imc/entry/the_specifics_of_adf_12c Note: you should have properly configured Node Manager utility for managing OHS instances Let’s consider configuration process step by step: 1. Shut down all Weblogic instances of existing domain including Admin Server; 2. Install Oracle HTTP Server. You should use your Fusion Middleware Home Path (e.g. /u01/Oracle/FMW12) for Installation Location and select Colocated HTTP Server option as Installation Type. I will not focus on this topic in this post. All information related to OHS installation you could find here: http://docs.oracle.com/middleware/1212/webtier/WTINS/install_gui.htm#i1082009 3. Next we need to extend our existing domain with OHS component. In order to do this you should do the following: a. Run Fusion Middleware Configuration Wizard (ORACLE_HOME/oracle_common/common/bin/config.sh); b. On the step 1 select Update an existing domain option and point your Fusion Middleware Home Path; c. On the step 2 check Oracle HTTP Server, Oracle Enterprise Manager Plugin for WEBTIER templates; d. Go through other steps without any changes and finish configuration process. 4. Start Admin Server and all managed servers related to your cluster 5. Log in to Enterprise Manager FMW Control using http://<hostname>:<port>/em URL 6. Now we will create OHS instance within our Weblogic Domain Infrastructure. Navigate to Weblogic Domain -> Administration -> Create/Delete OHS menu item; 7. Enter to edit mode, clicking Changes -> Lock&Edit menu item; 8. Create new OHS instance clicking Create button; 9. Define Instance Name (e.g. DevOSH) and Machine parameters; 10. Now we need to define listen port. By default OHS will use 7777 port number for income HTTP requests. We could change it to any free port number we would like to use. In order to do it, right click on our created OHS instance (left hand panel) and navigate to Administration -> Port Configuration; 11. Click on record with port number 7777 and then click Edit button; 12. Change port number value (in our case this will be 8080) and then click OK button; 13. Now we need to edit mod_wl_ohs configuration in order to enable OHS to act as proxy for WebLogic Server Instances/Cluster; 14. In order to do it right click on our created OHS instance (left panel) and navigate to Administration -> mod_wl_ohs Configuration; a. In Weblogic Cluster you should enter cluster address (define <host:port> for all managed servers which participated in cluster), e.g: 192.168.56.2:7004,192.168.56.2:7005 b. Define Weblogic Port parameter at which the Oracle WebLogic Server host is listening for connection requests from the module (or from other servers); c. Check Dynamic Server List option. This will dynamically update cluster list for every request; d. In the Location table define list of endpoint locations which you would like to process. In order to do this click Add Row button and define Location, Weblogic Cluster, Path Trim and Path Prefix parameters (if required); e. Click Apply button in order to save changes. 15. Activate changes clicking Changes ? Activate Changes menu item; 16. Finally we will start configured OHS instance. Right click on OHS instance tree item under Web Tier folder, select Control -> Start Up menu item; 17. Ensure that OHS instance up and running and then test your environment. Run deployed application to your Weblogic Cluster accessing via OHS web proxy; Normal 0 false false false RU X-NONE X-NONE /* Style Definitions */ table.MsoNormalTable {mso-style-name:"Table Normal"; mso-tstyle-rowband-size:0; mso-tstyle-colband-size:0; mso-style-noshow:yes; mso-style-priority:99; mso-style-parent:""; mso-padding-alt:0cm 5.4pt 0cm 5.4pt; mso-para-margin-top:0cm; mso-para-margin-right:0cm; mso-para-margin-bottom:10.0pt; mso-para-margin-left:0cm; line-height:115%; mso-pagination:widow-orphan; font-size:11.0pt; font-family:"Calibri","sans-serif"; mso-ascii-font-family:Calibri; mso-ascii-theme-font:minor-latin; mso-hansi-font-family:Calibri; mso-hansi-theme-font:minor-latin; mso-bidi-font-family:"Times New Roman"; mso-bidi-theme-font:minor-bidi; mso-fareast-language:EN-US;}

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  • httpd high cpu usage slowing down server response

    - by max
    my client has a image sharing website with about 100.000 visitor per day it has been slowed down considerably since this morning when i checked processes i've notice high cpu usage from http .... some has suggested ddos attack ... i'm not a webmaster and i've no idea whts going on top top - 20:13:30 up 5:04, 4 users, load average: 4.56, 4.69, 4.59 Tasks: 284 total, 3 running, 281 sleeping, 0 stopped, 0 zombie Cpu(s): 12.1%us, 0.9%sy, 1.7%ni, 69.0%id, 16.4%wa, 0.0%hi, 0.0%si, 0.0%st Mem: 16037152k total, 15875096k used, 162056k free, 360468k buffers Swap: 4194288k total, 888k used, 4193400k free, 14050008k cached PID USER PR NI VIRT RES SHR S %CPU %MEM TIME+ COMMAND 4151 apache 20 0 277m 84m 3784 R 50.2 0.5 0:01.98 httpd 4115 apache 20 0 210m 16m 4480 S 18.3 0.1 0:00.60 httpd 12885 root 39 19 4296 692 308 S 13.0 0.0 11:09.53 gzip 4177 apache 20 0 214m 20m 3700 R 12.3 0.1 0:00.37 httpd 2219 mysql 20 0 4257m 198m 5668 S 11.0 1.3 42:49.70 mysqld 3691 apache 20 0 206m 14m 6416 S 1.7 0.1 0:03.38 httpd 3934 apache 20 0 211m 17m 4836 S 1.0 0.1 0:03.61 httpd 4098 apache 20 0 209m 17m 3912 S 1.0 0.1 0:04.17 httpd 4116 apache 20 0 211m 17m 4476 S 1.0 0.1 0:00.43 httpd 3867 apache 20 0 217m 23m 4672 S 0.7 0.1 1:03.87 httpd 4146 apache 20 0 209m 15m 3628 S 0.7 0.1 0:00.02 httpd 4149 apache 20 0 209m 15m 3616 S 0.7 0.1 0:00.02 httpd 12884 root 39 19 22336 2356 944 D 0.7 0.0 0:19.21 tar 4054 apache 20 0 206m 12m 4576 S 0.3 0.1 0:00.32 httpd another top top - 15:46:45 up 5:08, 4 users, load average: 5.02, 4.81, 4.64 Tasks: 288 total, 6 running, 281 sleeping, 0 stopped, 1 zombie Cpu(s): 18.4%us, 0.9%sy, 2.3%ni, 56.5%id, 21.8%wa, 0.0%hi, 0.0%si, 0.0%st Mem: 16037152k total, 15792196k used, 244956k free, 360924k buffers Swap: 4194288k total, 888k used, 4193400k free, 13983368k cached PID USER PR NI VIRT RES SHR S %CPU %MEM TIME+ COMMAND 4622 apache 20 0 209m 16m 3868 S 54.2 0.1 0:03.99 httpd 4514 apache 20 0 213m 20m 3924 R 50.8 0.1 0:04.93 httpd 4627 apache 20 0 221m 27m 4560 R 18.9 0.2 0:01.20 httpd 12885 root 39 19 4296 692 308 S 18.9 0.0 11:51.79 gzip 2219 mysql 20 0 4257m 199m 5668 S 18.3 1.3 43:19.04 mysqld 4512 apache 20 0 227m 33m 4736 R 5.6 0.2 0:01.93 httpd 4520 apache 20 0 213m 19m 4640 S 1.3 0.1 0:01.48 httpd 4590 apache 20 0 212m 19m 3932 S 1.3 0.1 0:00.06 httpd 4573 apache 20 0 210m 16m 3556 R 1.0 0.1 0:00.03 httpd 4562 root 20 0 15164 1388 952 R 0.7 0.0 0:00.08 top 98 root 20 0 0 0 0 S 0.3 0.0 0:04.89 kswapd0 100 root 39 19 0 0 0 S 0.3 0.0 0:02.85 khugepaged 4579 apache 20 0 209m 16m 3900 S 0.3 0.1 0:00.83 httpd 4637 apache 20 0 209m 15m 3668 S 0.3 0.1 0:00.03 httpd ps aux [root@server ~]# ps aux | grep httpd root 2236 0.0 0.0 207524 10124 ? Ss 15:09 0:03 /usr/sbin/http d -k start -DSSL apache 3087 2.7 0.1 226968 28232 ? S 20:04 0:06 /usr/sbin/http d -k start -DSSL apache 3170 2.6 0.1 221296 22292 ? R 20:05 0:05 /usr/sbin/http d -k start -DSSL apache 3171 9.0 0.1 225044 26768 ? R 20:05 0:17 /usr/sbin/http d -k start -DSSL apache 3188 1.5 0.1 223644 24724 ? S 20:05 0:03 /usr/sbin/http d -k start -DSSL apache 3197 2.3 0.1 215908 17520 ? S 20:05 0:04 /usr/sbin/http d -k start -DSSL apache 3198 1.1 0.0 211700 13000 ? S 20:05 0:02 /usr/sbin/http d -k start -DSSL apache 3272 2.4 0.1 219960 21540 ? S 20:06 0:03 /usr/sbin/http d -k start -DSSL apache 3273 2.0 0.0 211600 12804 ? S 20:06 0:03 /usr/sbin/http d -k start -DSSL apache 3279 3.7 0.1 229024 29900 ? S 20:06 0:05 /usr/sbin/http d -k start -DSSL apache 3280 1.2 0.0 0 0 ? Z 20:06 0:01 [httpd] <defun ct> apache 3285 2.9 0.1 218532 21604 ? S 20:06 0:04 /usr/sbin/http d -k start -DSSL apache 3287 30.5 0.4 265084 65948 ? R 20:06 0:43 /usr/sbin/http d -k start -DSSL apache 3297 1.9 0.1 216068 17332 ? S 20:06 0:02 /usr/sbin/http d -k start -DSSL apache 3342 2.7 0.1 216716 17828 ? S 20:06 0:03 /usr/sbin/http d -k start -DSSL apache 3356 1.6 0.1 217244 18296 ? S 20:07 0:01 /usr/sbin/http d -k start -DSSL apache 3365 6.4 0.1 226044 27428 ? S 20:07 0:06 /usr/sbin/http d -k start -DSSL apache 3396 0.0 0.1 213844 16120 ? S 20:07 0:00 /usr/sbin/http d -k start -DSSL apache 3399 5.8 0.1 215664 16772 ? S 20:07 0:05 /usr/sbin/http d -k start -DSSL apache 3422 0.7 0.1 214860 17380 ? S 20:07 0:00 /usr/sbin/http d -k start -DSSL apache 3435 3.3 0.1 216220 17460 ? S 20:07 0:02 /usr/sbin/http d -k start -DSSL apache 3463 0.1 0.0 212732 15076 ? S 20:08 0:00 /usr/sbin/http d -k start -DSSL apache 3492 0.0 0.0 207660 7552 ? S 20:08 0:00 /usr/sbin/http d -k start -DSSL apache 3493 1.4 0.1 218092 19188 ? S 20:08 0:00 /usr/sbin/http d -k start -DSSL apache 3500 1.9 0.1 224204 26100 ? R 20:08 0:00 /usr/sbin/http d -k start -DSSL apache 3501 1.7 0.1 216916 17916 ? S 20:08 0:00 /usr/sbin/http d -k start -DSSL apache 3502 0.0 0.0 207796 7732 ? S 20:08 0:00 /usr/sbin/http d -k start -DSSL apache 3505 0.0 0.0 207660 7548 ? S 20:08 0:00 /usr/sbin/http d -k start -DSSL apache 3529 0.0 0.0 207660 7524 ? S 20:08 0:00 /usr/sbin/http d -k start -DSSL apache 3531 4.0 0.1 216180 17280 ? S 20:08 0:00 /usr/sbin/http d -k start -DSSL apache 3532 0.0 0.0 207656 7464 ? S 20:08 0:00 /usr/sbin/http d -k start -DSSL apache 3543 1.4 0.1 217088 18648 ? S 20:08 0:00 /usr/sbin/http d -k start -DSSL apache 3544 0.0 0.0 207656 7548 ? S 20:08 0:00 /usr/sbin/http d -k start -DSSL apache 3545 0.0 0.0 207656 7560 ? S 20:08 0:00 /usr/sbin/http d -k start -DSSL apache 3546 0.0 0.0 207660 7540 ? S 20:08 0:00 /usr/sbin/http d -k start -DSSL apache 3547 0.0 0.0 207660 7544 ? S 20:08 0:00 /usr/sbin/http d -k start -DSSL apache 3548 2.3 0.1 216904 17888 ? S 20:08 0:00 /usr/sbin/http d -k start -DSSL apache 3550 0.0 0.0 207660 7540 ? S 20:08 0:00 /usr/sbin/http d -k start -DSSL apache 3551 0.0 0.0 207660 7536 ? S 20:08 0:00 /usr/sbin/http d -k start -DSSL apache 3552 0.2 0.0 214104 15972 ? S 20:08 0:00 /usr/sbin/http d -k start -DSSL apache 3553 6.5 0.1 216740 17712 ? S 20:08 0:00 /usr/sbin/http d -k start -DSSL apache 3554 6.3 0.1 216156 17260 ? S 20:08 0:00 /usr/sbin/http d -k start -DSSL apache 3555 0.0 0.0 207796 7716 ? S 20:08 0:00 /usr/sbin/http d -k start -DSSL apache 3556 1.8 0.0 211588 12580 ? S 20:08 0:00 /usr/sbin/http d -k start -DSSL apache 3557 0.0 0.0 207660 7544 ? S 20:08 0:00 /usr/sbin/http d -k start -DSSL apache 3565 0.0 0.0 207660 7520 ? S 20:08 0:00 /usr/sbin/http d -k start -DSSL apache 3570 0.0 0.0 207660 7516 ? S 20:08 0:00 /usr/sbin/http d -k start -DSSL apache 3571 0.0 0.0 207660 7504 ? S 20:08 0:00 /usr/sbin/http d -k start -DSSL root 3577 0.0 0.0 103316 860 pts/2 S+ 20:08 0:00 grep httpd httpd error log [Mon Jul 01 18:53:38 2013] [error] [client 2.178.12.67] request failed: error reading the headers, referer: http://akstube.com/image/show/27023/%D9%86%DB%8C%D9%88%D8%B4%D8%A7-%D8%B6%DB%8C%D8%BA%D9%85%DB%8C-%D9%88-%D8%AE%D9%88%D8%A7%D9%87%D8%B1-%D9%88-%D9%87%D9%85%D8%B3%D8%B1%D8%B4 [Mon Jul 01 18:55:33 2013] [error] [client 91.229.215.240] request failed: error reading the headers, referer: http://akstube.com/image/show/44924 [Mon Jul 01 18:57:02 2013] [error] [client 2.178.12.67] Invalid method in request [Mon Jul 01 18:57:02 2013] [error] [client 2.178.12.67] File does not exist: /var/www/html/501.shtml [Mon Jul 01 19:21:36 2013] [error] [client 127.0.0.1] client denied by server configuration: /var/www/html/server-status [Mon Jul 01 19:21:36 2013] [error] [client 127.0.0.1] File does not exist: /var/www/html/403.shtml [Mon Jul 01 19:23:57 2013] [error] [client 151.242.14.31] request failed: error reading the headers [Mon Jul 01 19:37:16 2013] [error] [client 2.190.16.65] request failed: error reading the headers [Mon Jul 01 19:56:00 2013] [error] [client 151.242.14.31] request failed: error reading the headers Not a JPEG file: starts with 0x89 0x50 also there is lots of these in the messages log Jul 1 20:15:47 server named[2426]: client 203.88.6.9#11926: query (cache) 'www.xxxmaza.com/A/IN' denied Jul 1 20:15:47 server named[2426]: client 203.88.6.9#26255: query (cache) 'www.xxxmaza.com/A/IN' denied Jul 1 20:15:48 server named[2426]: client 203.88.6.9#20093: query (cache) 'www.xxxmaza.com/A/IN' denied Jul 1 20:15:48 server named[2426]: client 203.88.6.9#8672: query (cache) 'www.xxxmaza.com/A/IN' denied Jul 1 15:45:07 server named[2426]: client 203.88.6.9#39352: query (cache) 'www.xxxmaza.com/A/IN' denied Jul 1 15:45:08 server named[2426]: client 203.88.6.9#25382: query (cache) 'www.xxxmaza.com/A/IN' denied Jul 1 15:45:08 server named[2426]: client 203.88.6.9#9064: query (cache) 'www.xxxmaza.com/A/IN' denied Jul 1 15:45:09 server named[2426]: client 203.88.23.9#35375: query (cache) 'xxxmaza.com/A/IN' denied Jul 1 15:45:09 server named[2426]: client 203.88.6.9#61932: query (cache) 'www.xxxmaza.com/A/IN' denied Jul 1 15:45:09 server named[2426]: client 203.88.23.9#4423: query (cache) 'xxxmaza.com/A/IN' denied Jul 1 15:45:09 server named[2426]: client 203.88.6.9#40229: query (cache) 'www.xxxmaza.com/A/IN' denied Jul 1 15:45:14 server named[2426]: client 203.88.23.9#46128: query (cache) 'xxxmaza.com/A/IN' denied Jul 1 15:45:14 server named[2426]: client 203.88.6.10#62128: query (cache) 'www.xxxmaza.com/A/IN' denied Jul 1 15:45:14 server named[2426]: client 203.88.23.9#35240: query (cache) 'xxxmaza.com/A/IN' denied Jul 1 15:45:14 server named[2426]: client 203.88.6.10#36774: query (cache) 'www.xxxmaza.com/A/IN' denied Jul 1 15:45:14 server named[2426]: client 203.88.23.9#28361: query (cache) 'xxxmaza.com/A/IN' denied Jul 1 15:45:14 server named[2426]: client 203.88.6.10#14970: query (cache) 'www.xxxmaza.com/A/IN' denied Jul 1 15:45:14 server named[2426]: client 203.88.23.9#20216: query (cache) 'www.xxxmaza.com/A/IN' denied Jul 1 15:45:14 server named[2426]: client 203.88.23.10#31794: query (cache) 'xxxmaza.com/A/IN' denied Jul 1 15:45:14 server named[2426]: client 203.88.23.9#23042: query (cache) 'www.xxxmaza.com/A/IN' denied Jul 1 15:45:14 server named[2426]: client 203.88.6.10#11333: query (cache) 'www.xxxmaza.com/A/IN' denied Jul 1 15:45:14 server named[2426]: client 203.88.23.10#41807: query (cache) 'xxxmaza.com/A/IN' denied Jul 1 15:45:14 server named[2426]: client 203.88.23.9#20092: query (cache) 'www.xxxmaza.com/A/IN' denied Jul 1 15:45:14 server named[2426]: client 203.88.6.10#43526: query (cache) 'www.xxxmaza.com/A/IN' denied Jul 1 15:45:15 server named[2426]: client 203.88.23.9#17173: query (cache) 'www.xxxmaza.com/A/IN' denied Jul 1 15:45:15 server named[2426]: client 203.88.23.9#62412: query (cache) 'www.xxxmaza.com/A/IN' denied Jul 1 15:45:15 server named[2426]: client 203.88.23.10#63961: query (cache) 'xxxmaza.com/A/IN' denied Jul 1 15:45:15 server named[2426]: client 203.88.23.10#64345: query (cache) 'xxxmaza.com/A/IN' denied Jul 1 15:45:15 server named[2426]: client 203.88.23.10#31030: query (cache) 'xxxmaza.com/A/IN' denied Jul 1 15:45:16 server named[2426]: client 203.88.6.9#17098: query (cache) 'www.xxxmaza.com/A/IN' denied Jul 1 15:45:16 server named[2426]: client 203.88.6.9#17197: query (cache) 'www.xxxmaza.com/A/IN' denied Jul 1 15:45:16 server named[2426]: client 203.88.6.9#18114: query (cache) 'www.xxxmaza.com/A/IN' denied Jul 1 15:45:16 server named[2426]: client 203.88.6.9#59138: query (cache) 'www.xxxmaza.com/A/IN' denied Jul 1 15:45:17 server named[2426]: client 203.88.6.9#28715: query (cache) 'www.xxxmaza.com/A/IN' denied Jul 1 15:48:33 server named[2426]: client 203.88.23.9#26355: query (cache) 'xxxmaza.com/A/IN' denied Jul 1 15:48:34 server named[2426]: client 203.88.23.9#34473: query (cache) 'xxxmaza.com/A/IN' denied Jul 1 15:48:34 server named[2426]: client 203.88.23.9#62658: query (cache) 'xxxmaza.com/A/IN' denied Jul 1 15:48:34 server named[2426]: client 203.88.23.9#51631: query (cache) 'xxxmaza.com/A/IN' denied Jul 1 15:48:35 server named[2426]: client 203.88.23.9#54701: query (cache) 'xxxmaza.com/A/IN' denied Jul 1 15:48:36 server named[2426]: client 203.88.6.10#63694: query (cache) 'xxxmaza.com/A/IN' denied Jul 1 15:48:36 server named[2426]: client 203.88.6.10#18203: query (cache) 'xxxmaza.com/A/IN' denied Jul 1 15:48:37 server named[2426]: client 203.88.6.10#9029: query (cache) 'xxxmaza.com/A/IN' denied Jul 1 15:48:38 server named[2426]: client 203.88.6.10#58981: query (cache) 'xxxmaza.com/A/IN' denied Jul 1 15:48:38 server named[2426]: client 203.88.6.10#29321: query (cache) 'xxxmaza.com/A/IN' denied Jul 1 15:49:47 server named[2426]: client 119.160.127.42#42355: query (cache) 'xxxmaza.com/A/IN' denied Jul 1 15:49:49 server named[2426]: client 119.160.120.42#46285: query (cache) 'xxxmaza.com/A/IN' denied Jul 1 15:49:53 server named[2426]: client 119.160.120.42#30696: query (cache) 'xxxmaza.com/A/IN' denied Jul 1 15:49:54 server named[2426]: client 119.160.127.42#14038: query (cache) 'xxxmaza.com/A/IN' denied Jul 1 15:49:55 server named[2426]: client 119.160.120.42#33586: query (cache) 'xxxmaza.com/A/IN' denied Jul 1 15:49:56 server named[2426]: client 119.160.127.42#55114: query (cache) 'xxxmaza.com/A/IN' denied

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  • Java HTTP Request Occasionally Hangs

    - by behrk2
    Hello Everyone, For the majority of the time, my HTTP Requests work with no problem. However, occasionally they will hang. The code that I am using is set up so that if the request succeeds (with a response code of 200 or 201), then call screen.requestSucceeded(). If the request fails, then call screen.requestFailed(). When the request hangs, however, it does so before one of the above methods are called. Is there something wrong with my code? Should I be using some sort of best practice to prevent any hanging? The following is my code. I would appreciate any help. Thanks! HttpConnection connection = (HttpConnection) Connector.open(url + connectionParameters); connection.setRequestMethod(method); connection.setRequestProperty("WWW-Authenticate", "OAuth realm=api.netflix.com"); if (method.equals("POST")) { connection.setRequestProperty("Content-type", "application/x-www-form-urlencoded"); } int responseCode = connection.getResponseCode(); System.out.println("RESPONSE CODE: " + responseCode); if (connection instanceof HttpsConnection) { HttpsConnection secureConnection = (HttpsConnection) connection; String issuer = secureConnection.getSecurityInfo() .getServerCertificate().getIssuer(); UiApplication.getUiApplication().invokeLater( new DialogRunner( "Secure Connection! Certificate issued by: " + issuer)); } if (responseCode != 200 && responseCode != 201) { screen.requestFailed("Unexpected response code: " + responseCode); connection.close(); return; } String contentType = connection.getHeaderField("Content-type"); ByteArrayOutputStream baos = new ByteArrayOutputStream(); InputStream responseData = connection.openInputStream(); byte[] buffer = new byte[20000]; int bytesRead = 0; while ((bytesRead = responseData.read(buffer)) > 0) { baos.write(buffer, 0, bytesRead); } baos.close(); connection.close(); screen.requestSucceeded(baos.toByteArray(), contentType); } catch (IOException ex) { screen.requestFailed(ex.toString()); }

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  • How to connect to a SOAP webServices with Android

    - by dom4
    Hi everyone,I'm programming an application who must send coordinate and request to a WebServices this is my code: private String SOAP_ACTION = "getAllPositions"; private String METHOD_NAME = "getAllPositions"; private String NAMESPACE = "http://session/"; private static final String URL ="http://192.41.218.56:8080/WSGeoEAR-WSGeoServer/NavFinderBean?WSDL"; /** Called when the activity is first created. */ @Override public void onCreate(Bundle icicle) { super.onCreate(icicle); setContentView(R.layout.main); SoapObject request = new SoapObject(NAMESPACE, METHOD_NAME); request.addProperty("idUtente",1); SoapSerializationEnvelope envelope = new SoapSerializationEnvelope(SoapEnvelope.VER11); envelope.dotNet = true; envelope.setOutputSoapObject(request); AndroidHttpTransport androidHttpTransport = new AndroidHttpTransport(URL); androidHttpTransport.setXmlVersionTag("<?xml version=\"1.0\" encoding=\"UTF-8\"?>"); androidHttpTransport.debug = true; try{ androidHttpTransport.call(SOAP_ACTION, envelope); SoapObject resultsRequestSOAP = (SoapObject) envelope.bodyIn; ArrayList<position> resultData = (ArrayList<position>)resultsRequestSOAP.getProperty("getAllPositionsResponse"); for(position p : resultData) { ((TextView)findViewById(R.id.lblStatus)).setText(p.getAllInformation()); } } catch(Exception E) { ((TextView)findViewById(R.id.lblStatus)).setText("ERROR:" + E.getClass().getName() + ": " + E.getMessage()); } } } I've also create a class position. It doesn't work,can someone help me?Thanks

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  • Cocoa Basic HTTP Authentication : Advice Needed..

    - by Kristiaan
    Hello all, im looking to read the contents of a webpage that is secured with a user name and password. this is a mac OS X application NOT an iphone app so most of the things i have read on here or been suggested to read do not seem to work. Also i am a total beginner with Xcode and Obj C i was told to have a look at a website that provided sample code to http auth however so far i have had little luck in getting this working. below is the main code for the button press in my application, there is also another unit called Base64 below that has some code in i had to change to even get it compiling (no idea if what i changed is correct mind you). NSURL *url = [NSURL URLWithString:@"my URL"]; NSString *userName = @"UN"; NSString *password = @"PW"; NSError *myError = nil; // create a plaintext string in the format username:password NSMutableString *loginString = (NSMutableString*)[@"" stringByAppendingFormat:@"%@:%@", userName, password]; // employ the Base64 encoding above to encode the authentication tokens char *encodedLoginData = [base64 encode:[loginString dataUsingEncoding:NSUTF8StringEncoding]]; // create the contents of the header NSString *authHeader = [@"Basic " stringByAppendingFormat:@"%@", [NSString stringWithCString:encodedLoginData length:strlen(encodedLoginData)]]; //NSString *authHeader = [@"Basic " stringByAppendingFormat:@"%@", loginString];//[NSString stringWithString:loginString length:strlen(loginString)]]; NSMutableURLRequest *request = [NSMutableURLRequest requestWithURL: url cachePolicy: NSURLRequestReloadIgnoringCacheData timeoutInterval: 3]; // add the header to the request. Here's the $$$!!! [request addValue:authHeader forHTTPHeaderField:@"Authorization"]; // perform the reqeust NSURLResponse *response; NSData *data = [NSURLConnection sendSynchronousRequest: request returningResponse: &response error: &myError]; //*error = myError; // POW, here's the content of the webserver's response. NSString *result = [NSString stringWithCString:[data bytes] length:[data length]]; [myTextView setString:result]; code from the BASE64 file #import "base64.h" static char *alphabet = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+-"; @implementation Base64 +(char *)encode:(NSData *)plainText { // create an adequately sized buffer for the output. every 3 bytes // become four basically with padding to the next largest integer // divisible by four. char * encodedText = malloc((((([plainText length] % 3) + [plainText length]) / 3) * 4) + 1); char* inputBuffer = malloc([plainText length]); inputBuffer = (char *)[plainText bytes]; int i; int j = 0; // encode, this expands every 3 bytes to 4 for(i = 0; i < [plainText length]; i += 3) { encodedText[j++] = alphabet[(inputBuffer[i] & 0xFC) >> 2]; encodedText[j++] = alphabet[((inputBuffer[i] & 0x03) << 4) | ((inputBuffer[i + 1] & 0xF0) >> 4)]; if(i + 1 >= [plainText length]) // padding encodedText[j++] = '='; else encodedText[j++] = alphabet[((inputBuffer[i + 1] & 0x0F) << 2) | ((inputBuffer[i + 2] & 0xC0) >> 6)]; if(i + 2 >= [plainText length]) // padding encodedText[j++] = '='; else encodedText[j++] = alphabet[inputBuffer[i + 2] & 0x3F]; } // terminate the string encodedText[j] = 0; return encodedText;//outputBuffer; } @end when executing the code it stops on the following line with a EXC_BAD_ACCESS ?!?!? NSString *authHeader = [@"Basic " stringByAppendingFormat:@"%@", [NSString stringWithCString:encodedLoginData length:strlen(encodedLoginData)]]; any help would be appreciated as i am a little clueless on this problem, not being very literate with Cocoa, objective c, xcode is only adding fuel to this fire for me.

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  • Custom webserver caching

    - by Mark Kinsella
    I'm working with a custom webserver on an embedded system and having some problems correctly setting my HTTP Headers for caching. Our webserver is generating all dynamic content as XML and we're using semi-static XSL files to display it with some dynamic JSON requests thrown in for good measure along with semi-static images. I say "semi-static" because the problems occur when we need to do a firmware update which might change the XSL and image files. Here's what needs to be done: cache the XSL and image files and do not cache the XML and JSON responses. I have full control over the HTTP response and am currently: Using ETags with the XSL and image files, using the modified time and size to generate the ETag Setting Cache-Control: no-cache on the XML and JSON responses As I said, everything works dandy until a firmware update when the XSL and image files are sometimes cached. I've seen it work fine with the latest versions of Firefox and Safari but have had some problems with IE. I know one solution to this problem would be simply rename the XSL and image files after each version (eg. logo-v1.1.png, logo-v1.2.png) and set the Expires header to a date in the future but this would be difficult with the XSL files and I'd like to avoid this. Note: There is a clock on the unit but requires the user to set it and might not be 100% reliable which is what might be causing my caching issues when using ETags. What's the best practice that I should employ? I'd like to avoid as many webserver requests as possible but invalidating old XSL and image files after a software update is the #1 priority.

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  • Email Tracking - GMail

    - by Abs
    Hello all, I am creating my own email tracking system for email marketing tracking. I have been able to determine each persons email client they are using by using the http referrer but for some reason GMAIL does not send a HTTP_REFERRER at all! So I am trying to find another way of identifying when gmail requests a transparent image from my server. I get the following headers print_r($_SERVER);: DOCUMENT_ROOT = /usr/local/apache/htdocs GATEWAY_INTERFACE = CGI/1.1 HTTP_ACCEPT = */* HTTP_ACCEPT_CHARSET = ISO-8859-1,utf-8;q=0.7,*;q=0.3 HTTP_ACCEPT_ENCODING = gzip,deflate,sdch HTTP_ACCEPT_LANGUAGE = en-GB,en-US;q=0.8,en;q=0.6 HTTP_CONNECTION = keep-alive HTTP_COOKIE = __utmz=156230011.1290976484.1.1.utmcsr=(direct)|utmccn=(direct)|utmcmd=(none); __utma=156230011.422791272.1290976484.1293034866.1293050468.7 HTTP_HOST = xx.xxx.xx.xxx HTTP_USER_AGENT = Mozilla/5.0 (Windows; U; Windows NT 6.1; en-US) AppleWebKit/534.10 (KHTML, like Gecko) Chrome/8.0.552.237 Safari/534.10 PATH = /bin:/usr/bin QUERY_STRING = i=MTA= REDIRECT_STATUS = 200 REMOTE_ADDR = xx.xxx.xx.xxx REMOTE_PORT = 61296 REQUEST_METHOD = GET Is there anything of use in that list? Or is there something else I can do to actually get the http referrer, if not how are other ESPs managing to find whether gmail was used to view an email? Btw, I appreciate it if we can hold back on whether this is ethical or not as many ESPs do this already, I just don't want to pay for their service and I want to do it internally. Thanks all for any implementation advice. Update Just thought I would update this question and make it clearer in light of the bounty. I would like to find out when a user opens my email when sent to a GMail inbox. Assume, I have the usual transparent image tracking and the user does not block images. I would like to do this with the single request and the header details I get when the transparent image is requested.

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  • A Taxonomy of Numerical Methods v1

    - by JoshReuben
    Numerical Analysis – When, What, (but not how) Once you understand the Math & know C++, Numerical Methods are basically blocks of iterative & conditional math code. I found the real trick was seeing the forest for the trees – knowing which method to use for which situation. Its pretty easy to get lost in the details – so I’ve tried to organize these methods in a way that I can quickly look this up. I’ve included links to detailed explanations and to C++ code examples. I’ve tried to classify Numerical methods in the following broad categories: Solving Systems of Linear Equations Solving Non-Linear Equations Iteratively Interpolation Curve Fitting Optimization Numerical Differentiation & Integration Solving ODEs Boundary Problems Solving EigenValue problems Enjoy – I did ! Solving Systems of Linear Equations Overview Solve sets of algebraic equations with x unknowns The set is commonly in matrix form Gauss-Jordan Elimination http://en.wikipedia.org/wiki/Gauss%E2%80%93Jordan_elimination C++: http://www.codekeep.net/snippets/623f1923-e03c-4636-8c92-c9dc7aa0d3c0.aspx Produces solution of the equations & the coefficient matrix Efficient, stable 2 steps: · Forward Elimination – matrix decomposition: reduce set to triangular form (0s below the diagonal) or row echelon form. If degenerate, then there is no solution · Backward Elimination –write the original matrix as the product of ints inverse matrix & its reduced row-echelon matrix à reduce set to row canonical form & use back-substitution to find the solution to the set Elementary ops for matrix decomposition: · Row multiplication · Row switching · Add multiples of rows to other rows Use pivoting to ensure rows are ordered for achieving triangular form LU Decomposition http://en.wikipedia.org/wiki/LU_decomposition C++: http://ganeshtiwaridotcomdotnp.blogspot.co.il/2009/12/c-c-code-lu-decomposition-for-solving.html Represent the matrix as a product of lower & upper triangular matrices A modified version of GJ Elimination Advantage – can easily apply forward & backward elimination to solve triangular matrices Techniques: · Doolittle Method – sets the L matrix diagonal to unity · Crout Method - sets the U matrix diagonal to unity Note: both the L & U matrices share the same unity diagonal & can be stored compactly in the same matrix Gauss-Seidel Iteration http://en.wikipedia.org/wiki/Gauss%E2%80%93Seidel_method C++: http://www.nr.com/forum/showthread.php?t=722 Transform the linear set of equations into a single equation & then use numerical integration (as integration formulas have Sums, it is implemented iteratively). an optimization of Gauss-Jacobi: 1.5 times faster, requires 0.25 iterations to achieve the same tolerance Solving Non-Linear Equations Iteratively find roots of polynomials – there may be 0, 1 or n solutions for an n order polynomial use iterative techniques Iterative methods · used when there are no known analytical techniques · Requires set functions to be continuous & differentiable · Requires an initial seed value – choice is critical to convergence à conduct multiple runs with different starting points & then select best result · Systematic - iterate until diminishing returns, tolerance or max iteration conditions are met · bracketing techniques will always yield convergent solutions, non-bracketing methods may fail to converge Incremental method if a nonlinear function has opposite signs at 2 ends of a small interval x1 & x2, then there is likely to be a solution in their interval – solutions are detected by evaluating a function over interval steps, for a change in sign, adjusting the step size dynamically. Limitations – can miss closely spaced solutions in large intervals, cannot detect degenerate (coinciding) solutions, limited to functions that cross the x-axis, gives false positives for singularities Fixed point method http://en.wikipedia.org/wiki/Fixed-point_iteration C++: http://books.google.co.il/books?id=weYj75E_t6MC&pg=PA79&lpg=PA79&dq=fixed+point+method++c%2B%2B&source=bl&ots=LQ-5P_taoC&sig=lENUUIYBK53tZtTwNfHLy5PEWDk&hl=en&sa=X&ei=wezDUPW1J5DptQaMsIHQCw&redir_esc=y#v=onepage&q=fixed%20point%20method%20%20c%2B%2B&f=false Algebraically rearrange a solution to isolate a variable then apply incremental method Bisection method http://en.wikipedia.org/wiki/Bisection_method C++: http://numericalcomputing.wordpress.com/category/algorithms/ Bracketed - Select an initial interval, keep bisecting it ad midpoint into sub-intervals and then apply incremental method on smaller & smaller intervals – zoom in Adv: unaffected by function gradient à reliable Disadv: slow convergence False Position Method http://en.wikipedia.org/wiki/False_position_method C++: http://www.dreamincode.net/forums/topic/126100-bisection-and-false-position-methods/ Bracketed - Select an initial interval , & use the relative value of function at interval end points to select next sub-intervals (estimate how far between the end points the solution might be & subdivide based on this) Newton-Raphson method http://en.wikipedia.org/wiki/Newton's_method C++: http://www-users.cselabs.umn.edu/classes/Summer-2012/csci1113/index.php?page=./newt3 Also known as Newton's method Convenient, efficient Not bracketed – only a single initial guess is required to start iteration – requires an analytical expression for the first derivative of the function as input. Evaluates the function & its derivative at each step. Can be extended to the Newton MutiRoot method for solving multiple roots Can be easily applied to an of n-coupled set of non-linear equations – conduct a Taylor Series expansion of a function, dropping terms of order n, rewrite as a Jacobian matrix of PDs & convert to simultaneous linear equations !!! Secant Method http://en.wikipedia.org/wiki/Secant_method C++: http://forum.vcoderz.com/showthread.php?p=205230 Unlike N-R, can estimate first derivative from an initial interval (does not require root to be bracketed) instead of inputting it Since derivative is approximated, may converge slower. Is fast in practice as it does not have to evaluate the derivative at each step. Similar implementation to False Positive method Birge-Vieta Method http://mat.iitm.ac.in/home/sryedida/public_html/caimna/transcendental/polynomial%20methods/bv%20method.html C++: http://books.google.co.il/books?id=cL1boM2uyQwC&pg=SA3-PA51&lpg=SA3-PA51&dq=Birge-Vieta+Method+c%2B%2B&source=bl&ots=QZmnDTK3rC&sig=BPNcHHbpR_DKVoZXrLi4nVXD-gg&hl=en&sa=X&ei=R-_DUK2iNIjzsgbE5ID4Dg&redir_esc=y#v=onepage&q=Birge-Vieta%20Method%20c%2B%2B&f=false combines Horner's method of polynomial evaluation (transforming into lesser degree polynomials that are more computationally efficient to process) with Newton-Raphson to provide a computational speed-up Interpolation Overview Construct new data points for as close as possible fit within range of a discrete set of known points (that were obtained via sampling, experimentation) Use Taylor Series Expansion of a function f(x) around a specific value for x Linear Interpolation http://en.wikipedia.org/wiki/Linear_interpolation C++: http://www.hamaluik.com/?p=289 Straight line between 2 points à concatenate interpolants between each pair of data points Bilinear Interpolation http://en.wikipedia.org/wiki/Bilinear_interpolation C++: http://supercomputingblog.com/graphics/coding-bilinear-interpolation/2/ Extension of the linear function for interpolating functions of 2 variables – perform linear interpolation first in 1 direction, then in another. Used in image processing – e.g. texture mapping filter. Uses 4 vertices to interpolate a value within a unit cell. Lagrange Interpolation http://en.wikipedia.org/wiki/Lagrange_polynomial C++: http://www.codecogs.com/code/maths/approximation/interpolation/lagrange.php For polynomials Requires recomputation for all terms for each distinct x value – can only be applied for small number of nodes Numerically unstable Barycentric Interpolation http://epubs.siam.org/doi/pdf/10.1137/S0036144502417715 C++: http://www.gamedev.net/topic/621445-barycentric-coordinates-c-code-check/ Rearrange the terms in the equation of the Legrange interpolation by defining weight functions that are independent of the interpolated value of x Newton Divided Difference Interpolation http://en.wikipedia.org/wiki/Newton_polynomial C++: http://jee-appy.blogspot.co.il/2011/12/newton-divided-difference-interpolation.html Hermite Divided Differences: Interpolation polynomial approximation for a given set of data points in the NR form - divided differences are used to approximately calculate the various differences. For a given set of 3 data points , fit a quadratic interpolant through the data Bracketed functions allow Newton divided differences to be calculated recursively Difference table Cubic Spline Interpolation http://en.wikipedia.org/wiki/Spline_interpolation C++: https://www.marcusbannerman.co.uk/index.php/home/latestarticles/42-articles/96-cubic-spline-class.html Spline is a piecewise polynomial Provides smoothness – for interpolations with significantly varying data Use weighted coefficients to bend the function to be smooth & its 1st & 2nd derivatives are continuous through the edge points in the interval Curve Fitting A generalization of interpolating whereby given data points may contain noise à the curve does not necessarily pass through all the points Least Squares Fit http://en.wikipedia.org/wiki/Least_squares C++: http://www.ccas.ru/mmes/educat/lab04k/02/least-squares.c Residual – difference between observed value & expected value Model function is often chosen as a linear combination of the specified functions Determines: A) The model instance in which the sum of squared residuals has the least value B) param values for which model best fits data Straight Line Fit Linear correlation between independent variable and dependent variable Linear Regression http://en.wikipedia.org/wiki/Linear_regression C++: http://www.oocities.org/david_swaim/cpp/linregc.htm Special case of statistically exact extrapolation Leverage least squares Given a basis function, the sum of the residuals is determined and the corresponding gradient equation is expressed as a set of normal linear equations in matrix form that can be solved (e.g. using LU Decomposition) Can be weighted - Drop the assumption that all errors have the same significance –-> confidence of accuracy is different for each data point. Fit the function closer to points with higher weights Polynomial Fit - use a polynomial basis function Moving Average http://en.wikipedia.org/wiki/Moving_average C++: http://www.codeproject.com/Articles/17860/A-Simple-Moving-Average-Algorithm Used for smoothing (cancel fluctuations to highlight longer-term trends & cycles), time series data analysis, signal processing filters Replace each data point with average of neighbors. Can be simple (SMA), weighted (WMA), exponential (EMA). Lags behind latest data points – extra weight can be given to more recent data points. Weights can decrease arithmetically or exponentially according to distance from point. Parameters: smoothing factor, period, weight basis Optimization Overview Given function with multiple variables, find Min (or max by minimizing –f(x)) Iterative approach Efficient, but not necessarily reliable Conditions: noisy data, constraints, non-linear models Detection via sign of first derivative - Derivative of saddle points will be 0 Local minima Bisection method Similar method for finding a root for a non-linear equation Start with an interval that contains a minimum Golden Search method http://en.wikipedia.org/wiki/Golden_section_search C++: http://www.codecogs.com/code/maths/optimization/golden.php Bisect intervals according to golden ratio 0.618.. Achieves reduction by evaluating a single function instead of 2 Newton-Raphson Method Brent method http://en.wikipedia.org/wiki/Brent's_method C++: http://people.sc.fsu.edu/~jburkardt/cpp_src/brent/brent.cpp Based on quadratic or parabolic interpolation – if the function is smooth & parabolic near to the minimum, then a parabola fitted through any 3 points should approximate the minima – fails when the 3 points are collinear , in which case the denominator is 0 Simplex Method http://en.wikipedia.org/wiki/Simplex_algorithm C++: http://www.codeguru.com/cpp/article.php/c17505/Simplex-Optimization-Algorithm-and-Implemetation-in-C-Programming.htm Find the global minima of any multi-variable function Direct search – no derivatives required At each step it maintains a non-degenerative simplex – a convex hull of n+1 vertices. Obtains the minimum for a function with n variables by evaluating the function at n-1 points, iteratively replacing the point of worst result with the point of best result, shrinking the multidimensional simplex around the best point. Point replacement involves expanding & contracting the simplex near the worst value point to determine a better replacement point Oscillation can be avoided by choosing the 2nd worst result Restart if it gets stuck Parameters: contraction & expansion factors Simulated Annealing http://en.wikipedia.org/wiki/Simulated_annealing C++: http://code.google.com/p/cppsimulatedannealing/ Analogy to heating & cooling metal to strengthen its structure Stochastic method – apply random permutation search for global minima - Avoid entrapment in local minima via hill climbing Heating schedule - Annealing schedule params: temperature, iterations at each temp, temperature delta Cooling schedule – can be linear, step-wise or exponential Differential Evolution http://en.wikipedia.org/wiki/Differential_evolution C++: http://www.amichel.com/de/doc/html/ More advanced stochastic methods analogous to biological processes: Genetic algorithms, evolution strategies Parallel direct search method against multiple discrete or continuous variables Initial population of variable vectors chosen randomly – if weighted difference vector of 2 vectors yields a lower objective function value then it replaces the comparison vector Many params: #parents, #variables, step size, crossover constant etc Convergence is slow – many more function evaluations than simulated annealing Numerical Differentiation Overview 2 approaches to finite difference methods: · A) approximate function via polynomial interpolation then differentiate · B) Taylor series approximation – additionally provides error estimate Finite Difference methods http://en.wikipedia.org/wiki/Finite_difference_method C++: http://www.wpi.edu/Pubs/ETD/Available/etd-051807-164436/unrestricted/EAMPADU.pdf Find differences between high order derivative values - Approximate differential equations by finite differences at evenly spaced data points Based on forward & backward Taylor series expansion of f(x) about x plus or minus multiples of delta h. Forward / backward difference - the sums of the series contains even derivatives and the difference of the series contains odd derivatives – coupled equations that can be solved. Provide an approximation of the derivative within a O(h^2) accuracy There is also central difference & extended central difference which has a O(h^4) accuracy Richardson Extrapolation http://en.wikipedia.org/wiki/Richardson_extrapolation C++: http://mathscoding.blogspot.co.il/2012/02/introduction-richardson-extrapolation.html A sequence acceleration method applied to finite differences Fast convergence, high accuracy O(h^4) Derivatives via Interpolation Cannot apply Finite Difference method to discrete data points at uneven intervals – so need to approximate the derivative of f(x) using the derivative of the interpolant via 3 point Lagrange Interpolation Note: the higher the order of the derivative, the lower the approximation precision Numerical Integration Estimate finite & infinite integrals of functions More accurate procedure than numerical differentiation Use when it is not possible to obtain an integral of a function analytically or when the function is not given, only the data points are Newton Cotes Methods http://en.wikipedia.org/wiki/Newton%E2%80%93Cotes_formulas C++: http://www.siafoo.net/snippet/324 For equally spaced data points Computationally easy – based on local interpolation of n rectangular strip areas that is piecewise fitted to a polynomial to get the sum total area Evaluate the integrand at n+1 evenly spaced points – approximate definite integral by Sum Weights are derived from Lagrange Basis polynomials Leverage Trapezoidal Rule for default 2nd formulas, Simpson 1/3 Rule for substituting 3 point formulas, Simpson 3/8 Rule for 4 point formulas. For 4 point formulas use Bodes Rule. Higher orders obtain more accurate results Trapezoidal Rule uses simple area, Simpsons Rule replaces the integrand f(x) with a quadratic polynomial p(x) that uses the same values as f(x) for its end points, but adds a midpoint Romberg Integration http://en.wikipedia.org/wiki/Romberg's_method C++: http://code.google.com/p/romberg-integration/downloads/detail?name=romberg.cpp&can=2&q= Combines trapezoidal rule with Richardson Extrapolation Evaluates the integrand at equally spaced points The integrand must have continuous derivatives Each R(n,m) extrapolation uses a higher order integrand polynomial replacement rule (zeroth starts with trapezoidal) à a lower triangular matrix set of equation coefficients where the bottom right term has the most accurate approximation. The process continues until the difference between 2 successive diagonal terms becomes sufficiently small. Gaussian Quadrature http://en.wikipedia.org/wiki/Gaussian_quadrature C++: http://www.alglib.net/integration/gaussianquadratures.php Data points are chosen to yield best possible accuracy – requires fewer evaluations Ability to handle singularities, functions that are difficult to evaluate The integrand can include a weighting function determined by a set of orthogonal polynomials. Points & weights are selected so that the integrand yields the exact integral if f(x) is a polynomial of degree <= 2n+1 Techniques (basically different weighting functions): · Gauss-Legendre Integration w(x)=1 · Gauss-Laguerre Integration w(x)=e^-x · Gauss-Hermite Integration w(x)=e^-x^2 · Gauss-Chebyshev Integration w(x)= 1 / Sqrt(1-x^2) Solving ODEs Use when high order differential equations cannot be solved analytically Evaluated under boundary conditions RK for systems – a high order differential equation can always be transformed into a coupled first order system of equations Euler method http://en.wikipedia.org/wiki/Euler_method C++: http://rosettacode.org/wiki/Euler_method First order Runge–Kutta method. Simple recursive method – given an initial value, calculate derivative deltas. Unstable & not very accurate (O(h) error) – not used in practice A first-order method - the local error (truncation error per step) is proportional to the square of the step size, and the global error (error at a given time) is proportional to the step size In evolving solution between data points xn & xn+1, only evaluates derivatives at beginning of interval xn à asymmetric at boundaries Higher order Runge Kutta http://en.wikipedia.org/wiki/Runge%E2%80%93Kutta_methods C++: http://www.dreamincode.net/code/snippet1441.htm 2nd & 4th order RK - Introduces parameterized midpoints for more symmetric solutions à accuracy at higher computational cost Adaptive RK – RK-Fehlberg – estimate the truncation at each integration step & automatically adjust the step size to keep error within prescribed limits. At each step 2 approximations are compared – if in disagreement to a specific accuracy, the step size is reduced Boundary Value Problems Where solution of differential equations are located at 2 different values of the independent variable x à more difficult, because cannot just start at point of initial value – there may not be enough starting conditions available at the end points to produce a unique solution An n-order equation will require n boundary conditions – need to determine the missing n-1 conditions which cause the given conditions at the other boundary to be satisfied Shooting Method http://en.wikipedia.org/wiki/Shooting_method C++: http://ganeshtiwaridotcomdotnp.blogspot.co.il/2009/12/c-c-code-shooting-method-for-solving.html Iteratively guess the missing values for one end & integrate, then inspect the discrepancy with the boundary values of the other end to adjust the estimate Given the starting boundary values u1 & u2 which contain the root u, solve u given the false position method (solving the differential equation as an initial value problem via 4th order RK), then use u to solve the differential equations. Finite Difference Method For linear & non-linear systems Higher order derivatives require more computational steps – some combinations for boundary conditions may not work though Improve the accuracy by increasing the number of mesh points Solving EigenValue Problems An eigenvalue can substitute a matrix when doing matrix multiplication à convert matrix multiplication into a polynomial EigenValue For a given set of equations in matrix form, determine what are the solution eigenvalue & eigenvectors Similar Matrices - have same eigenvalues. Use orthogonal similarity transforms to reduce a matrix to diagonal form from which eigenvalue(s) & eigenvectors can be computed iteratively Jacobi method http://en.wikipedia.org/wiki/Jacobi_method C++: http://people.sc.fsu.edu/~jburkardt/classes/acs2_2008/openmp/jacobi/jacobi.html Robust but Computationally intense – use for small matrices < 10x10 Power Iteration http://en.wikipedia.org/wiki/Power_iteration For any given real symmetric matrix, generate the largest single eigenvalue & its eigenvectors Simplest method – does not compute matrix decomposition à suitable for large, sparse matrices Inverse Iteration Variation of power iteration method – generates the smallest eigenvalue from the inverse matrix Rayleigh Method http://en.wikipedia.org/wiki/Rayleigh's_method_of_dimensional_analysis Variation of power iteration method Rayleigh Quotient Method Variation of inverse iteration method Matrix Tri-diagonalization Method Use householder algorithm to reduce an NxN symmetric matrix to a tridiagonal real symmetric matrix vua N-2 orthogonal transforms     Whats Next Outside of Numerical Methods there are lots of different types of algorithms that I’ve learned over the decades: Data Mining – (I covered this briefly in a previous post: http://geekswithblogs.net/JoshReuben/archive/2007/12/31/ssas-dm-algorithms.aspx ) Search & Sort Routing Problem Solving Logical Theorem Proving Planning Probabilistic Reasoning Machine Learning Solvers (eg MIP) Bioinformatics (Sequence Alignment, Protein Folding) Quant Finance (I read Wilmott’s books – interesting) Sooner or later, I’ll cover the above topics as well.

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  • SQL – NuoDB and Third Party Explorer – SQuirreL SQL Client, SQL Workbench/J and DbVisualizer

    - by Pinal Dave
    I recently wrote a four-part series on how I started to learn about and begin my journey with NuoDB. Big Data is indeed a big world and the learning of the Big Data is like spaghetti – no one knows in reality where to start, so I decided to learn it with the help of NuoDB. You can download NuoDB and continue your journey with me as well. Part 1 – Install NuoDB in 90 Seconds Part 2 – Manage NuoDB Installation Part 3 – Explore NuoDB Database Part 4 – Migrate from SQL Server to NuoDB …and in this blog post we will try to answer the most asked question about NuoDB. “I like the NuoDB Explorer but can I connect to NuoDB from my preferred Graphical User Interface?” Honestly, I did not expect this question to be asked of me so many times but from the question it is clear that we developers absolutely want to learn new things and along with that we do want to continue to use our most efficient developer tools. Now here is the answer to the question: “Absolutely, you can continue to use any of the following most popular SQL clients.” NuoDB supports the three most popular 3rd-party SQL clients. In all the leading development environments there are always more than one database installed and managing each of them with a different tool is often a very difficult task. Developers like to use one tool, which can control most of the databases. Once developers are familiar with one database tool it is very difficult for them to switch to another tool. This is particularly difficult when we developers find that tool to be the key reason for our efficiency. Let us see how to install each of the NuoDB supported 3rd party tools along with a quick tutorial on how to go about using them. SQuirreL SQL Client First download SQuirreL Universal SQL client. On the Windows platform you can double-click on the file and it will install the SQuirrel client. Once it is installed, open the application and it will bring up the following screen. Now go to the Drivers tab on the left side and scroll it down. You will find NuoDB mentioned there. Now right click over it and click on Modify Driver. Now here is where you need to make sure that you make proper entries or your client will not work with the database. Enter following values: Name: NuoDB Example URL: jdbc:com:nuodb://localhost:48004/test Website URL: http://www.nuodb.com Now click on the Extra Class Path tab and Add the location of the nuodbjdbc.jar file. If you are following my blog posts and have installed NuoDB in the default location, you will find the default path as C:\Program Files\NuoDB\jar\nuodbjdbc.jar. The class name of the driver is automatically populated. Once you click OK you will see that there is a small icon displayed to the left of NuoDB, which shows that you have successfully configured and installed the NuoDB driver. Now click on the tab of Alias tab and you can notice that it is empty. Now click on the big Plus icon and it will open screen of adding an alias. “Alias” means nothing more than adding a database to your system. The database name of the original installation can be anything and, if you wish, you can register the database with any other alternative name. Here are the details you should fill into the Alias screen below. Name: Test (or your preferred alias) Driver: NuoDB URL: jdbc:com:nuodb://localhost:48004/test (This is for test database) User Name: dba (This is the username which I entered for test Database) Password: goalie (This is the password which I entered for test Database) Check Auto Logon and Connect at Startup and click on OK. That’s it! You are done. On the right side you will see a table name and on the left side you will see various tabs with all the relevant details from respective table. You can see various metadata, schemas, data types and other information in the table. In addition, you can also generate script and do various important tasks related to database. You can see how easy it is to configure NuoDB with the SQuirreL Client and get going with it immediately. SQL Workbench/J This is another wonderful client tool, which works very well with NuoDB. The best part is that in the Driver dropdown you will see NuoDB being mentioned there. Click here to download  SQL Workbench/J Universal SQL client. The download process is straight forward and the installation is a very easy process for SQL Workbench/J. As soon as you open the client, you will notice on following screen the NuoDB driver when selecting a New Connection Profile. Select NuoDB from the drop down and click on OK. In the driver information, enter following details: Driver: NuoDB (com.nuodb.jdbc.Driver) URL: jdbc:com.nuodb://localhost/test Username: dba Password: goalie While clicking on OK, it will bring up the following pop-up. Click Yes to edit the driver information. Click on OK and it will bring you to following screen. This is the screen where you can perform various tasks. You can write any SQL query you want and it will instantly show you the results. Now click on the database icon, which you see right on the left side of the word User=dba.  Once you click on Database Explorer, you can perform various database related tasks. As a developer, one of my favorite tasks is to look at the source of the table as it gives me a proper view of the structure of the database. I find SQL Workbench/J very efficient in doing the same. DbVisualizer DBVisualizer is another great tool, which helps you to connect to NuoDB and retrieve database information in your desired format. A developer who is familiar with DBVisualizer will find this client to be very easy to work with. The installation of the DBVisualizer is very pretty straight forward. When we open the client, it will bring us to the following screen. As a first step we need to set up the driver. Go to Tools >> Driver Manager. It will bring up following screen where we set up the diver. Click on Create Driver and it will open up the driver settings on the right side. On the right side of the area where it displays Driver Settings please enter the following values- Name: NuoDB URL Format: jdbc:com.nuodb://localhost:48004/test Now under the driver path, click on the folder icon and it will ask for the location of the jar file. Provide the path as a C:\Program Files\NuoDB\jar\nuodbjdbc.jar and click OK. You will notice there is a green button displayed at the bottom right corner. This means the driver is configured properly. Once driver is configured properly, we can go to Create Database Connection and create a database. If the pop up show up for the Wizard. Click on No Wizard and continue to enter the settings manually. Here is the Database Connection screen. This screen can be bit tricky. Here are the settings you need to remember to enter. Name: NuoDB Database Type: Generic Driver: NuoDB Database URL: jdbc:com.nuodb://localhost:48004/test Database Userid: dba Database Password: goalie Once you enter the values, click on Connect. Once Connect is pressed, it will change the button value to Reconnect if the connection is successfully established and it will show the connection details on lthe eft side. When we further explore the NuoDB, we can see various tables created in our test application. We can further click on the right side screen and see various details on the table. If you click on the Data Tab, it will display the entire data of the table. The Tools menu also has some very interesting and cool features like Driver Manager, Data Monitor and SQL History. Summary Well, this was a relatively long post but I find it is extremely essential to cover all the three important clients, which we developers use in our daily database development. Here is my question to you? Which one of the following is your favorite NuoDB 3rd-Party Database Client? (Pick One) SQuirreL SQL Client SQL Workbench/J DbVisualizer I will be very much eager to read your experience about NuoDB. You can download NuoDB from here. Reference: Pinal Dave (http://blog.SQLAuthority.com) Filed under: Big Data, PostADay, SQL, SQL Authority, SQL Query, SQL Server, SQL Tips and Tricks, T SQL, Technology Tagged: NuoDB

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