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• how to create a telnet connction in delphi applications

  - by Monica

  i want to create a telnet connection in delphi that will allow me to connect to the command prompt on my computer.

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• How do I detect server status in a port scanner java implementation

  - by akz

  I am writing a port scanner in Java and I want to be able to distinct the following 4 use cases: port is open port is open and server banner was read port is closed server is not live I have the following code: InetAddress address = InetAddress.getByName("google.com"); int[] ports = new int[]{21, 22, 23, 80, 443}; for (int i = 0; i < ports.length; i++) { int port = ports[i]; Socket socket = null; try { socket = new Socket(address, port); socket.setSoTimeout(500); System.out.println("port " + port + " open"); BufferedReader reader = new BufferedReader( new InputStreamReader(socket.getInputStream())); String line = reader.readLine(); if (line != null) { System.out.println(line); } socket.close(); } catch (SocketTimeoutException ex) { // port was open but nothing was read from input stream ex.printStackTrace(); } catch (ConnectException ex) { // port is closed ex.printStackTrace(); } catch (IOException e) { e.printStackTrace(); } finally { if (socket != null && !socket.isClosed()) { try { socket.close(); } catch (Exception e) { e.printStackTrace(); } } } } The problem is that I get a ConnectionException both when the port is closed and the server cannot be reached but with a different exception message: java.net.ConnectException: Connection timed out: connect when the connection was never established and java.net.ConnectException: Connection refused: connect when the port was closed so I cannot make the distinction between the two use cases without digging into the actual exception message. Same thing happens when I try a different approach for the socket creation. If I use: socket = new Socket(); socket.setSoTimeout(500); socket.connect(new InetSocketAddress(address, port), 1000); I have the same problem but with the SocketTimeoutException instead. I get a java.net.SocketTimeoutException: Read timed out if port was open but there was no banner to be read and java.net.SocketTimeoutException: connect timed out if server is not live or port is closed. Any ideas? Thanks in advance!

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• How do i set Savepoints for Linq to SQL and use "NO" ExecuteCommand ?

  - by nik

  TransactionScope TransactionABC = new TransactionScope(); try { context.Connection.Open(); { context.ExecuteCommand("insert into test (test) values (1)") context.SubmitChanges(); context.ExecuteCommand("savepoint test"); context.ExecuteCommand("insert into test (test) values (2)") context.SubmitChanges(); context.ExecuteCommand("rollback to test"); } TransactionABC.Complete(); TransactionABC.Dispose(); } catch (Exception ec) { MessageBox.Show(" ", ec.Message); } finally { context.Connection.Close(); } It works, but only with ExecuteCommand. I want to use a function, because i can't see what happens in the savepoint !

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• MongoDB db.serverStatus() gives error when running using tunnel that is targetted to api.cloudfoundry.com

  - by Ajay

  Following is the console session... C:\Users\xxx>vmc tunnel myMongoDB Getting tunnel connection info: OK Service connection info: username : uuuu password : pppp name : db url : mongodb://uuuu:[email protected]:25200/db Starting tunnel to myMongoDB on port 10000. 1: none 2: mongo 3: mongodump 4: mongorestore Which client would you like to start?: 2 Launching 'mongo --host localhost --port 10000 -u uuuu -p pppp db' MongoDB shell version: 2.0.6 connecting to: localhost:10000/db > db.serverStatus() { "errmsg" : "need to login", "ok" : 0 } > Which credentials should I use to login (assuming should use db.auth) to get rid of the error "{ "errmsg" : "need to login", "ok" : 0 }". When I run the same in micro CF on my machine it works ok and gives me the expected output. P.S. I'm trying this to get to know the current connections on my application, written in node.js. Trying to debug some issues with connections to the DB. If there is any other alternative that I can use please suggest that as well.

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• mysql data being inserted twice via php

  - by Jascha

  I can't for the life of me figure out why this function is causing multiple entries into my database table... When I run the function I end up with two records stacked on top of each one second apart here is the function: function generate_signup_token(){ $connection = new DB_Connect(); // <--- my database connection class $ip = mysql_real_escape_string($_SERVER['REMOTE_ADDR']); $sign_up_token = uniqid(mt_rand(), true); $_SESSION['signup_token'] = $sign_up_token; $sign_up_token = mysql_real_escape_string($sign_up_token); $query = "INSERT INTO `token_manager` (`ip_address`, `signup_token`) VALUES ('$ip', '$sign_up_token')"; mysql_query($query); } generate_signup_token();

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• drop down list checked

  - by KareemSaad

  I had Drop down list which execute code when specific condition and I tried to check it through selected value but it get error protected void DDLProductFamily_SelectedIndexChanged(object sender, EventArgs e) { if (DDLProductFamily.Items.FindByText("Name").Selected == true) using (SqlConnection Con = Connection.GetConnection()) { SqlCommand Com = new SqlCommand("GetListViewByProductCategory", Con); Com.CommandType = CommandType.StoredProcedure; Com.Parameters.Add(Parameter.NewInt("@ProductCategory_Id", DDLProductFamily.SelectedValue.ToString())); SqlDataAdapter DA = new SqlDataAdapter(Com); DA.Fill(dt); DataList1.DataSource = dt; DataList1.DataBind(); } else if (DDLProductFamily.Items.FindByText("ProductFamilly").Selected == true) { using (SqlConnection Con = Connection.GetConnection()) { SqlCommand Com = new SqlCommand("GetListViewByProductFamily", Con); Com.CommandType = CommandType.StoredProcedure; Com.Parameters.Add(Parameter.NewInt("@ProductFamily_Id", DDLProductFamily.SelectedValue.ToString())); SqlDataAdapter DA = new SqlDataAdapter(Com); DA.Fill(dt); DataList1.DataSource = dt; DataList1.DataBind(); } } }

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• ATI propriatery drivers install latest 12.8, broke my kernel. Stuck on kernel 3.2.0-26

  - by user66987

  I messed up a bit. Hoping some here can help me. I tried to install the newest catalyst 12.8. Sadly, this broke my system. I was stuck in low graphics mode. I finally managed to restore the proprietary drivers, and get into ubuntu again. But now I am stuck on kernel 3.2.0.26. I had installed kernel 3.2.0-30, but the system no longer sees it. I have kernel 3.2.0-29 too, but the system cannot see that as well. In the grub menu. When I use sudo update-grub, they are both listed. Here are the output I get: Searching for GRUB installation directory ... found: /boot/grub Cannot determine root device. Assuming /dev/hda1 This error is probably caused by an invalid /etc/fstab Searching for default file ... found: /boot/grub/default Testing for an existing GRUB menu.lst file ... found: /boot/grub/menu.lst Searching for splash image ... none found, skipping ... Found kernel: /boot/vmlinuz-3.2.0-30-generic Found kernel: /boot/vmlinuz-3.2.0-29-generic Found kernel: /boot/vmlinuz-3.2.0-27-generic Found kernel: /boot/vmlinuz-3.2.0-26-generic Found GRUB 2: /boot/grub/core.img Found kernel: /boot/memtest86+.bin Updating /boot/grub/menu.lst ... done I have searched everywhere to find a solution to my problem, but can't find any solutions. If you need any log outputs to figure out the problem, please let me know which ones. Update: here is the output for grub.cfg # # DO NOT EDIT THIS FILE # # It is automatically generated by grub-mkconfig using templates # from /etc/grub.d and settings from /etc/default/grub # ### BEGIN /etc/grub.d/00_header ### if [ -s $prefix/grubenv ]; then set have_grubenv=true load_env fi set default="0" if [ "${prev_saved_entry}" ]; then set saved_entry="${prev_saved_entry}" save_env saved_entry set prev_saved_entry= save_env prev_saved_entry set boot_once=true fi function savedefault { if [ -z "${boot_once}" ]; then saved_entry="${chosen}" save_env saved_entry fi } function recordfail { set recordfail=1 if [ -n "${have_grubenv}" ]; then if [ -z "${boot_once}" ]; then save_env recordfail; fi; fi } function load_video { insmod vbe insmod vga insmod video_bochs insmod video_cirrus } insmod part_msdos insmod ext2 set root='(hd2,msdos1)' search --no-floppy --fs-uuid --set=root 270c7c58-06d8-4e6b-b9bb-8d92f46adc0b if loadfont /usr/share/grub/unicode.pf2 ; then set gfxmode=auto load_video insmod gfxterm insmod part_msdos insmod ext2 set root='(hd2,msdos1)' search --no-floppy --fs-uuid --set=root 270c7c58-06d8-4e6b-b9bb-8d92f46adc0b set locale_dir=($root)/boot/grub/locale set lang=nb_NO insmod gettext fi terminal_output gfxterm if [ "${recordfail}" = 1 ]; then set timeout=-1 else set timeout=10 fi ### END /etc/grub.d/00_header ### ### BEGIN /etc/grub.d/05_debian_theme ### set menu_color_normal=white/black set menu_color_highlight=black/light-gray if background_color 44,0,30; then clear fi ### END /etc/grub.d/05_debian_theme ### ### BEGIN /etc/grub.d/10_linux ### function gfxmode { set gfxpayload="${1}" if [ "${1}" = "keep" ]; then set vt_handoff=vt.handoff=7 else set vt_handoff= fi } if [ "${recordfail}" != 1 ]; then if [ -e ${prefix}/gfxblacklist.txt ]; then if hwmatch ${prefix}/gfxblacklist.txt 3; then if [ ${match} = 0 ]; then set linux_gfx_mode=keep else set linux_gfx_mode=text fi else set linux_gfx_mode=text fi else set linux_gfx_mode=keep fi else set linux_gfx_mode=text fi export linux_gfx_mode if [ "${linux_gfx_mode}" != "text" ]; then load_video; fi menuentry 'Ubuntu, med Linux 3.2.0-26-generic' --class ubuntu --class gnu-linux --class gnu --class os { recordfail gfxmode $linux_gfx_mode insmod gzio insmod part_msdos insmod ext2 set root='(hd2,msdos1)' search --no-floppy --fs-uuid --set=root 270c7c58-06d8-4e6b-b9bb-8d92f46adc0b linux /boot/vmlinuz-3.2.0-26-generic root=UUID=270c7c58-06d8-4e6b-b9bb-8d92f46adc0b ro quiet splash $vt_handoff initrd /boot/initrd.img-3.2.0-26-generic } menuentry 'Ubuntu, med Linux 3.2.0-26-generic (gjenopprettelsesmodus)' --class ubuntu --class gnu-linux --class gnu --class os { recordfail insmod gzio insmod part_msdos insmod ext2 set root='(hd2,msdos1)' search --no-floppy --fs-uuid --set=root 270c7c58-06d8-4e6b-b9bb-8d92f46adc0b echo 'Laster Linux 3.2.0-26-generic ...' linux /boot/vmlinuz-3.2.0-26-generic root=UUID=270c7c58-06d8-4e6b-b9bb-8d92f46adc0b ro recovery nomodeset echo 'Loading initial ramdisk ...' initrd /boot/initrd.img-3.2.0-26-generic } submenu "Previous Linux versions" { menuentry 'Ubuntu, med Linux 3.2.0-25-generic' --class ubuntu --class gnu-linux --class gnu --class os { recordfail gfxmode $linux_gfx_mode insmod gzio insmod part_msdos insmod ext2 set root='(hd2,msdos1)' search --no-floppy --fs-uuid --set=root 270c7c58-06d8-4e6b-b9bb-8d92f46adc0b linux /boot/vmlinuz-3.2.0-25-generic root=UUID=270c7c58-06d8-4e6b-b9bb-8d92f46adc0b ro quiet splash $vt_handoff initrd /boot/initrd.img-3.2.0-25-generic } menuentry 'Ubuntu, med Linux 3.2.0-25-generic (gjenopprettelsesmodus)' --class ubuntu --class gnu-linux --class gnu --class os { recordfail insmod gzio insmod part_msdos insmod ext2 set root='(hd2,msdos1)' search --no-floppy --fs-uuid --set=root 270c7c58-06d8-4e6b-b9bb-8d92f46adc0b echo 'Laster Linux 3.2.0-25-generic ...' linux /boot/vmlinuz-3.2.0-25-generic root=UUID=270c7c58-06d8-4e6b-b9bb-8d92f46adc0b ro recovery nomodeset echo 'Loading initial ramdisk ...' initrd /boot/initrd.img-3.2.0-25-generic } menuentry 'Ubuntu, med Linux 3.2.0-24-generic' --class ubuntu --class gnu-linux --class gnu --class os { recordfail gfxmode $linux_gfx_mode insmod gzio insmod part_msdos insmod ext2 set root='(hd2,msdos1)' search --no-floppy --fs-uuid --set=root 270c7c58-06d8-4e6b-b9bb-8d92f46adc0b linux /boot/vmlinuz-3.2.0-24-generic root=UUID=270c7c58-06d8-4e6b-b9bb-8d92f46adc0b ro quiet splash $vt_handoff initrd /boot/initrd.img-3.2.0-24-generic } menuentry 'Ubuntu, med Linux 3.2.0-24-generic (gjenopprettelsesmodus)' --class ubuntu --class gnu-linux --class gnu --class os { recordfail insmod gzio insmod part_msdos insmod ext2 set root='(hd2,msdos1)' search --no-floppy --fs-uuid --set=root 270c7c58-06d8-4e6b-b9bb-8d92f46adc0b echo 'Laster Linux 3.2.0-24-generic ...' linux /boot/vmlinuz-3.2.0-24-generic root=UUID=270c7c58-06d8-4e6b-b9bb-8d92f46adc0b ro recovery nomodeset echo 'Loading initial ramdisk ...' initrd /boot/initrd.img-3.2.0-24-generic } menuentry 'Ubuntu, med Linux 3.2.0-23-generic' --class ubuntu --class gnu-linux --class gnu --class os { recordfail gfxmode $linux_gfx_mode insmod gzio insmod part_msdos insmod ext2 set root='(hd2,msdos1)' search --no-floppy --fs-uuid --set=root 270c7c58-06d8-4e6b-b9bb-8d92f46adc0b linux /boot/vmlinuz-3.2.0-23-generic root=UUID=270c7c58-06d8-4e6b-b9bb-8d92f46adc0b ro quiet splash $vt_handoff initrd /boot/initrd.img-3.2.0-23-generic } menuentry 'Ubuntu, med Linux 3.2.0-23-generic (gjenopprettelsesmodus)' --class ubuntu --class gnu-linux --class gnu --class os { recordfail insmod gzio insmod part_msdos insmod ext2 set root='(hd2,msdos1)' search --no-floppy --fs-uuid --set=root 270c7c58-06d8-4e6b-b9bb-8d92f46adc0b echo 'Laster Linux 3.2.0-23-generic ...' linux /boot/vmlinuz-3.2.0-23-generic root=UUID=270c7c58-06d8-4e6b-b9bb-8d92f46adc0b ro recovery nomodeset echo 'Loading initial ramdisk ...' initrd /boot/initrd.img-3.2.0-23-generic } } ### END /etc/grub.d/10_linux ### ### BEGIN /etc/grub.d/20_linux_xen ### ### END /etc/grub.d/20_linux_xen ### ### BEGIN /etc/grub.d/20_memtest86+ ### menuentry "Memory test (memtest86+)" { insmod part_msdos insmod ext2 set root='(hd2,msdos1)' search --no-floppy --fs-uuid --set=root 270c7c58-06d8-4e6b-b9bb-8d92f46adc0b linux16 /boot/memtest86+.bin } menuentry "Memory test (memtest86+, serial console 115200)" { insmod part_msdos insmod ext2 set root='(hd2,msdos1)' search --no-floppy --fs-uuid --set=root 270c7c58-06d8-4e6b-b9bb-8d92f46adc0b linux16 /boot/memtest86+.bin console=ttyS0,115200n8 } ### END /etc/grub.d/20_memtest86+ ### ### BEGIN /etc/grub.d/30_os-prober ### menuentry "Windows 7 (loader) (on /dev/sdb1)" --class windows --class os { insmod part_msdos insmod ntfs set root='(hd1,msdos1)' search --no-floppy --fs-uuid --set=root 448AF3CE8AF3BA8E chainloader +1 } ### END /etc/grub.d/30_os-prober ### ### BEGIN /etc/grub.d/40_custom ### # This file provides an easy way to add custom menu entries. Simply type the # menu entries you want to add after this comment. Be careful not to change # the 'exec tail' line above. ### END /etc/grub.d/40_custom ### ### BEGIN /etc/grub.d/41_custom ### if [ -f $prefix/custom.cfg ]; then source $prefix/custom.cfg; fi ### END /etc/grub.d/41_custom ### How can I set kernel 3.2.0.30 as the default kernel? According to this file, kernel 3.2.0-30 does not exist.

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• How do I find the IP address of a GPRS modem?

  - by Hanno Fietz

  I want to pull data from a device that is accessed via a serial protocol and has a GPRS modem attached which should allow transparent access over an IP connection. It seems to me that this approach is upside down, because how should I know at which IP address the device currently is? Unfortunately, the device itself is rather dumb, so I can't make it send something to my server, which would reveal the current IP. For home routers on dialup lines, there's dynamic DNS services. Is there something equivalent in the mobile world? Each modem would, of course, have its phone number as a reliable address, but how does that help me? Practically all material on GPRS etc. that I can find online seems to be concerned with initiating the connection from the modem side, since that's what the system is designed for.

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• Problem indexing files in Solr on Ubuntu

  - by nik

  Hi, What I want to do is index some documents in Solr and know how it works. I have installed Solr and Tomcat and can see Solr Admin UI at localhost:8080/ solr/ admin/ Now, I want to add some documents to the index, may I know how to proceed further? I find very less documentation on Internet regarding this. In the tutorial http://lucene.apache.org/solr/tutorial.html#Indexing+Data they asked to run java -jar post.jar solr.xml monitor.xml command but after running that I get connection refused error as it is jetty. After installing jetty I tried telnet: I get "Connection refused" error I am not able to understand what the problem is.

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• c++ networking issue- retrnsmittion without ccongestion

  - by gln

  I wrote an application in c++ which send data over tcp connection to several machines.as part of the protocol I use in my application, the other side sends hearbeat messages from time to time, then I know that the connection is still alive. now, I want this application to work on 100 machines or more at the same time. but, I see that sometimes I don't get these heartbeat messages although they sent: I see in wireshark that the packet arrived, then my OS doesn't ack on this message, so there are some retransmit without any ack from my OS. if I look in the window size property - I saw that there is no issue in this part. what can be the root cause for this behavior? it is something in my code that I should change? this is my select code: int res = select(fdCount, &readFds, NULL, NULL, NULL ); I'm using server 2008 r2. Please help me! thanks

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• PgJDBC: "no suitable driver found" when following tutorial, why?

  - by Celeritas

  I'm writing a Java program that queries a PostgreSQL database. I'm following this example and have trouble here: connection = DriverManager.getConnection( "jdbc:postgresql://127.0.0.1:5432/testdb", "mkyong", "123456"); According to the JavaDoc for DriverManager the first string is "a database url of the form jdbc:subprotocol:subname. When I connect to the server I type in psql -h dataserv.abc.company.com -d app -U emp24 and give the password qwe123 (for example sake). What should the first argument of getConnection be? I've tried connection = DriverManager.getConnection( "jdbc:postgresql://dataserv.abc.company.com", "emp24", "qwe123"); and get the run time error: no suitable driver found. I've download JDBC4 Postgresql Driver, Version 9.2-1000.

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• How to set utf8 in the auto-generated PHP code of flash builder 4 ?

  - by Mark

  HI, PHP problem here (I think): I've just created a Flex (Flash Builder) project with a datagrid linked to a database - the database is all utf8. When I run the project using the auto-generated code in flex4, the non-English part comes like ????? while the English part comes fine. The auto-generated PHP code uses mysqli. I've tried: $this->connection->set_charset('utf8'); or mysqli_query($this->connection,"SET NAMES utf8"); I also tried writing the code myself (I'm not a PHP guy): mysql_query("set names utf8"); was fine - but that's mysql and not mysqli (that's an "i" after the mysql) and I want to use the auto-generated code... any help is appreciated.

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• Reason for not properly closed socket?

  - by gc

  Here is what I am trying to do: The server sends message to connected clients when new messages are available. The client, on the other hand, when connected, tries to send a message to the server using send() and then receive message using recv(), right after that, the client calls close() to close the connection. Sometimes, after the client finishes, the server tries to receive message from client will result in a 104 - "connection reset by peer" error. When this happens, Wireshark reveals that the last two segments sent by the client is: 1. an ACK acknowledging the receipt of the message sent by the server 2. a RST/ACK No FIN is sent by the client. Why is this happening and how can I close the socket "properly" at the client?

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• Is is possible to intercept a constructor on a class you do not own?

  - by code poet

  Referring to my possible answer to this question: http://stackoverflow.com/questions/2907535/how-would-you-audit-asp-net-membership-tables-while-recording-what-user-made-the/2911616#2911616 Is it possible to intercept a call, coming from code you do not own, to a ctor on a sealed internal class that you do not own with the intention of manipulating the object before returning? Concrete example: SqlMembershipProvider, for all of it's data access, instantiates a connection helper class, System.Web.DataAccess.SqlConnectionHolder. The desired result is to intercept this instantiation and perform an operation on the public connection that is opened in the ctor of System.Web.DataAccess.SqlConnectionHolder before letting execution continue. Is this possible. If so, an brief example would be appreciated.

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• ADO.NET - DataRead Error

  - by user560706

  Hi, I am trying to display data from a column in my database onto my rich textbox, but I am getting mixed up between DataSet and DataReader - I know the majority of the code below is correct, I just get two lines containing errors, and I'm not sure why: // Create a connection string string ConnectionString = ("Provider=Microsoft.ACE.OLEDB.12.0;Data Source= C:\\Documents and Settings\\Harley\\Desktop\\Test.accdb"); string SQL = "SELECT * FROM Paragraph"; // create a connection object SqlConnection conn = new SqlConnection(ConnectionString); // Create a command object SqlCommand cmd = new SqlCommand(SQL, conn); conn.Open(); DataTable dt = new DataTable(); da.Fill(dt); //ERROR // Call ExecuteReader to return a DataReader SqlDataReader reader = cmd.ExecuteReader(); foreach(DataRow reader in dsRtn) //ERROR { richTextBox = richTextBox.Text + reader[0].ToString(); } //Release resources reader.Close(); conn.Close(); }

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• Look over my C# SQLite Query, what am I doing wrong?

  - by CODe

  I'm writing a WinForms database application using SQLite and C#. I have a sqlite query that is failing, and I'm unsure as to where I'm going wrong, as I've tried everything I could think of. public DataTable searchSubs(String businessName, String contactName) { string SQL = null; if ((businessName != null && businessName != "") && (contactName != null && contactName != "")) { // provided business name and contact name for search SQL = "SELECT * FROM SUBCONTRACTOR WHERE BusinessName LIKE %@BusinessName% AND Contact LIKE %@ContactName%"; } else if ((businessName != null && businessName != "") && (contactName == null || contactName == "")) { // provided business name only for search SQL = "SELECT * FROM SUBCONTRACTOR WHERE BusinessName LIKE %@BusinessName%"; } else if ((businessName == null || businessName == "") && (contactName != null && contactName != "")) { // provided contact name only for search SQL = "SELECT * FROM SUBCONTRACTOR WHERE Contact LIKE %@ContactName%"; } else if ((businessName == null || businessName == "") && (contactName == null || contactName == "")) { // provided no search information SQL = "SELECT * FROM SUBCONTRACTOR"; } SQLiteCommand cmd = new SQLiteCommand(SQL); cmd.Parameters.AddWithValue("@BusinessName", businessName); cmd.Parameters.AddWithValue("@ContactName", contactName); cmd.Connection = connection; SQLiteDataAdapter da = new SQLiteDataAdapter(cmd); DataSet ds = new DataSet(); try { da.Fill(ds); DataTable dt = ds.Tables[0]; return dt; } catch (Exception e) { MessageBox.Show(e.ToString()); return null; } finally { cmd.Dispose(); connection.Close(); } } I continually get an error saying that it is failing near the %'s. That's all fine and dandy, but I guess I'm structuring it wrong, but I don't know where! I tried adding apostrophes around the "like" variables, like this: SQL = "SELECT * FROM SUBCONTRACTOR WHERE Contact LIKE '%@ContactName%'"; and quite honestly, that is all I can think of. Anyone have any ideas?

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• How can I implement "real time" messaging on Google AppEngine?

  - by Freed

  I'm creating a web application on Google AppEngine where I want the user to be notified a quickly as possible after certain events occour. The problem is similar to say a chat server in that I need something happening on one connection (someone is writing a message in a chat room) to propagate to a number of other connections (other people in that chat room gets the message). To get speedy updates from the server to the client I'm planning on using long polling with XmlHttpRequest, hoping that AppEngine won't interfere other than possibly restriing the timeout. The real problem however is efficient notification between connections on AppEngine. Is there any support for this type of cross connection notification on AppEngine that does not involve busy-waiting? The only tools I can think of to do this at all is either using the data storage (slow) or memcache (unreliable), and none of them would let me avoid busy-waiting. Note: I know about XMPP support on AppEngine. It's related, but I want a browser based solution, sending messages to the users by XMPP is not an option.

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• How to retain one million simultaneous TCP connections?

  - by cow

  I am to design a server that needs to serve millions of clients that are simultaneously connected with the server via TCP. The data traffic between the server and the clients will be sparse, so bandwidth issues can be ignored. One important requirement is that whenever the server needs to send data to any client it should use the existing TCP connection instead of opening a new connection toward the client (because the client may be behind a firewall). Does anybody know how to do this, and what hardware/software is needed (at the least cost)? Thanks in advance for any suggestions.

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• [java] reading POST data from html form sent to serversocket.

  - by user32167

  i try to write simplest possible server app in Java, displaying html form with textarea input, which after submitting gives me possibility to parse xml typed in thet textarea. For now i build simple serversocket based server like that: import java.io.BufferedReader; import java.io.InputStreamReader; import java.io.PrintWriter; import java.net.ServerSocket; import java.net.Socket; public class WebServer { protected void start() { ServerSocket s; String gets = ""; System.out.println("Start on port 80"); try { // create the main server socket s = new ServerSocket(80); } catch (Exception e) { System.out.println("Error: " + e); return; } System.out.println("Waiting for connection"); for (;;) { try { // wait for a connection Socket remote = s.accept(); // remote is now the connected socket System.out.println("Connection, sending data."); BufferedReader in = new BufferedReader(new InputStreamReader( remote.getInputStream())); PrintWriter out = new PrintWriter(remote.getOutputStream()); String str = "."; while (!str.equals("")) { str = in.readLine(); if (str.contains("GET")){ gets = str; break; } } out.println("HTTP/1.0 200 OK"); out.println("Content-Type: text/html"); out.println(""); // Send the HTML page String method = "get"; out.print("<html><form method="+method+">"); out.print("<textarea name=we></textarea></br>"); out.print("<input type=text name=a><input type=submit></form></html>"); out.println(gets); out.flush(); remote.close(); } catch (Exception e) { System.out.println("Error: " + e); } } } public static void main(String args[]) { WebServer ws = new WebServer(); ws.start(); } } After form (textarea with xml and one additional text input) is submitted in 'gets' String-type variable I have Urlencoded values of my variables (also displayed on the screen, it looks like that: gets = GET /?we=%3Cnetwork+ip_addr%3D%2210.0.0.0%2F8%22+save_ip%3D%22true%22%3E%0D%0A%3Csubnet+interf_used%3D%22200%22+name%3D%22lan1%22+%2F%3E%0D%0A%3Csubnet+interf_used%3D%22254%22+name%3D%22lan2%22+%2F%3E%0D%0A%3C%2Fnetwork%3E&a=fooBar HTTP/1.1 What can i do to change GET to POST method (if i simply change it in form and than put " if (str.contains("GET")){" it gives me string like gets = POST / HTTP/1.1 with no variables. And after that, how i can use xml from my textarea field (called 'we')?

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• how does teamviewer find my computer even if my comp. behind of the firewall and firewall isn't conf

  - by uzay95

  Did you use teamviewer? (comic question i know... Who doesn't use it?) Do you have any idea how does teamviewer make connection even if i am behind the router, firewall, switch and my local firewall..? I'm trying to imagine a connection that is between remote machinge and my computer. Remote machine is sending the packets (and its header (for instance, destination IP, message body)) to me but it only knows my id number(which is given by my local teamviewer application). And this packets are reaching to my computer even if there is a juniper firewall (and also my windows firewall). What kind a message body is recieving by computer? (of course it is not like xml, text, html, excel :) Do you have any idea? PS. Please share your knowledge like you are explaining to beginner level user.

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• when get pagecontent from URL the connect alway return nopermistion ?

  - by tiendv

  I have a methor to return pagecontent of link but when it run, alway return "Do not perrmisson ", plesea check it here is code to return string pagecontent public static String getPageContent(String targetURL) throws Exception { Hashtable contentHash = new Hashtable(); URL url; URLConnection conn; // The data streams used to read from and write to the URL connection. DataOutputStream out; DataInputStream in; // String returned as the result . String returnString = ""; // Create the URL object and make a connection to it. url = new URL(targetURL); conn = url.openConnection(); // check out permission of acess URL if (conn.getPermission() != null) { returnString = "Do not Permission access URL "; } else { // Set connection parameters. We need to perform input and output, // so set both as true. conn.setDoInput(true); conn.setDoOutput(true); // Disable use of caches. conn.setUseCaches(false); // Set the content type we are POSTing. We impersonate it as // encoded form data conn.setRequestProperty("Content-Type", "application/x-www-form-urlencoded"); // get the output stream . out = new DataOutputStream(conn.getOutputStream()); String content = ""; // Create a single String value pairs for all the keys // in the Hashtable passed to us. Enumeration e = contentHash.keys(); boolean first = true; while (e.hasMoreElements()) { // For each key and value pair in the hashtable Object key = e.nextElement(); Object value = contentHash.get(key); // If this is not the first key-value pair in the hashtable, // concantenate an "&" sign to the constructed String if (!first) content += "&"; // append to a single string. Encode the value portion content += (String) key + "=" + URLEncoder.encode((String) value); first = false; } // Write out the bytes of the content string to the stream. out.writeBytes(content); out.flush(); out.close(); // check if can't read from URL // Read input from the input stream. in = new DataInputStream(conn.getInputStream()); String str; while (null != ((str = in.readLine()))) { returnString += str + "\n"; } in.close(); } // return the string that was read. return returnString; }

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• Can't catch newConnection() signal from QTcpServer

  - by Bob

  I am trying to make a simple server thread in QT to accept a connection, however although the server is listening (I can connect with my test app) I can't get the newConnection() signal to be acted on. Any help as to what I'm missing here would be much appreciated! class CServerThread : public QThread { Q_OBJECT protected: void run(); private: QTcpServer* server; public slots: void AcceptConnection(); }; void CServerThread::run() { server = new QTcpServer; QObject::connect(server, SIGNAL(newConnection()), this, SLOT(AcceptConnection())); server-listen(QHostAddress::Any, 1000); // Any port in a storm exec(); // Start event loop } void CServerThread::AcceptConnection() { OutputDebugStringA("\n***** INCOMING CONNECTION"); // This is never called! }

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• Sql query builder c# for windows mobile

  - by pdiddy

  I'm building a windows mobile app. And using SqlCe. I'm looking for a good sql query builder. So instead of writing "SELECT COLUMNS FROM TABLE WHERE etc... Is there a good free library that can build this sort of query? EDIT: You know when you write your code with ADO.net something like this SqlCeCommand command = new SqlCeCommand(Connection); command.CommandText = "SELECT * FROM Orders WHERE customerId = @customerId"; Well i'm looking for some library that could build that SELECT statement using classes instead of writing it through string. So something like: SqlCeCommand command = new SqlCeCommand(Connection); SqlQueryBuilder query = new SqlQueryBuilder(); query.Table = "Orders"; query.AddWhere("customerId", myValue) command.CommandText = query.toString(); Something like that .... so a class that will build the query..

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• Sqlite + Java: table not updating

  - by Ben L

  I'm using a Java wrapper for SQLite called SQLiteJDBC - this may have some bearing on any answers... I have a table which I've displayed in a GUI, within that UI I have a button for the fields for an individual row of that table. When I save my changes I do this... Statement stmt = connection.createStatement(); stmt.execute("update 'tableName' set 'fieldName'=1 where userid=1"); int updateCount = stmt.getUpdateCount(); My connection is valid, I get no exceptions thrown and getUpdateCount() returns '1' indicating that one row has been updated. However my table is not updated. I've spent the last few hours trying to work out what's going on but I'm not having any luck. Help!!

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• Is It possible to use the second part of this code for repository patterns and generics

  - by newToCSharp

  Is there any issues in using version 2,to get the same results as version 1. Or is this just bad coding. Any Ideas public class Customer { public int CustomerID { get; set; } public string EmailAddress { get; set; } int Age { get; set; } } public interface ICustomer { void AddNewCustomer(Customer Customer); void AddNewCustomer(string EmailAddress, int Age); void RemoveCustomer(Customer Customer); } public class BALCustomer { private readonly ICustomer dalCustomer; public BALCustomer(ICustomer dalCustomer) { this.dalCustomer = dalCustomer; } public void Add_A_New_Customer(Customer Customer) { dalCustomer.AddNewCustomer(Customer); } public void Remove_A_Existing_Customer(Customer Customer) { dalCustomer.RemoveCustomer(Customer); } } public class CustomerDataAccess : ICustomer { public void AddNewCustomer(Customer Customer) { // MAKE DB CONNECTION AND EXECUTE throw new NotImplementedException(); } public void AddNewCustomer(string EmailAddress, int Age) { // MAKE DB CONNECTION AND EXECUTE throw new NotImplementedException(); } public void RemoveCustomer(Customer Customer) { // MAKE DB CONNECTION AND EXECUTE throw new NotImplementedException(); } } // VERSION 2 public class Customer_New : DataRespository<CustomerDataAccess> { public int CustomerID { get; set; } public string EmailAddress { get; set; } public int Age { get; set; } } public class DataRespository<T> where T:class,new() { private T item = new T(); public T Execute { get { return item; } set { item = value; } } public void Update() { //TO BE CODED } public void Save() { //TO BE CODED } public void Remove() { //TO BE CODED } } class Program { static void Main(string[] args) { Customer_New cus = new Customer_New() { Age = 10, EmailAddress = "[email protected]" }; cus.Save(); cus.Execute.RemoveCustomer(new Customer()); // Repository Version Customer customer = new Customer() { EmailAddress = "[email protected]", CustomerID = 10 }; BALCustomer bal = new BALCustomer(new CustomerDataAccess()); bal.Add_A_New_Customer(customer); } } }

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