Search Results

Search found 17749 results on 710 pages for 'connection pool'.

Page 650/710 | < Previous Page | 646 647 648 649 650 651 652 653 654 655 656 657  | Next Page >

  • How do I save the edits for a checkbox that implements an email notification?

    - by Ralph The Mouf
    On my site, a user gets email notifications when someone comments on their profile, or comments on their blog etc...I have made a email settings page that has checkboxes to allow the user to decide to receive emails or not. This is what I am wrapping around the email notification code chunck for the pages that have the php mail: <?php if(isset($_POST['email_toggle']) && $_POST['email_toggle'] == 'true') { if(isset($_POST['commentProfileSubmit']) && $auth) { $query etc $to = etc } } My question is what do I put on the email settings script that has the actual check boxes to make them stay checked or unchecked once you submit your settings? Another words what do I put in the if(isset portion to implement the changes? if(isset($_POST['email_toggle']) && $_POST['email_toggle'] == 'true') { /* what do I put here? */ header("Location: Profile.php?id=" . $auth->id); mysql_query($query,$connection); /* input/check boxes and submit button */ <tr> <td class="email_check"> <input type="checkbox" name="email_toggle" value="true" checked="checked" /> Receive email Notifications When Someone Answers A Question You've Answered </td> </tr> <tr> <td> <input style="margin:10px 0px 0px 10px;" class="submit" type="submit" name="email_toggle" value="Save Settings" /> </td> </tr> }

    Read the article

  • eclipse stuck at running program

    - by user1434388
    This is the picture after I end task the eclipse. My Android Program has no errors, and before this problem it was all fine. It happened when I added some code into my program. It gets stuck after I click the run button. This also happens when I run my handphone for debugging the program. Other programs are all working fine, only one is stuck. When I try to remove and import it again seem there is a classes.dex file which I cannot delete, I have to restart my computer for it to allow to delete and I have to force the program to close. I have searched at this website and they said keep open the emulator but it doesn't work for me. below is the connecting coding that i added. //check internet connection private boolean chkConnectionStatus(){ ConnectivityManager connMgr = (ConnectivityManager) this.getSystemService(Context.CONNECTIVITY_SERVICE); final android.net.NetworkInfo wifi = connMgr.getNetworkInfo(ConnectivityManager.TYPE_WIFI); final android.net.NetworkInfo mobile = connMgr.getNetworkInfo(ConnectivityManager.TYPE_MOBILE); if( wifi.isAvailable() ){ return true; } else if( mobile.isAvailable() ){ return true; } else { Toast.makeText(this, "Check your internet" , Toast.LENGTH_LONG).show(); return false; } }

    Read the article

  • Working with PHP and MySQL - need a good and secure design with OO design

    - by Andrew
    I am new to PHP- first time developer. I am working on my web application and it is nearly done; nevertheless, most of my sql was done directly via code using direct mysql requests. This is the way I approached it: In classes_db.php I declared the db settings and created methods that I use to open and close DB connections. I declare those objects on my regular pages: class classes_db { public $dbserver = 'server; public $dbusername = 'user'; public $dbpassword = 'pass'; public $dbname = 'db'; function openDb() { $dbhandle = mysql_connect($this->dbserver, $this->dbusername, $this->dbpassword); if (!$dbhandle) { die('Could not connect: ' . mysql_error()); } $selected = mysql_select_db($this->dbname, $dbhandle) or die("Could not select the database"); return $dbhandle; } function closeDb($con) { mysql_close($con); } } On my regular page, I do this: <?php require 'classes_db.php'; session_start(); //create instance of the DB class $db = new classes_db(); //get dbhandle $dbhandle = $db->openDb(); //process query $result = mysql_query("update user set username = '" . $usernameFromForm . "' where iduser= " . $_SESSION['user']->iduser); //close the connection if (isset($dbhandle)) { $db->closeDb($dbhandle); } ?> My questions is: how to do it right and make it OO and secure? I know that I need incorporate prepared queries- how to do it the best way? Please provide some code

    Read the article

  • Multiple left joins, how to output in php

    - by Dan
    I have 3 tables I need to join. The contracts table is the main table, the 'jobs' and 'companies' table are extra info that can be associated to the contracts table. so, since I want all entries from my 'contracts' table, and the 'jobs' and 'companies' data only if it exists, I wrote the query like this.... $sql = "SELECT * FROM contracts LEFT JOIN jobs ON contracts.job_id = jobs.id LEFT JOIN companies ON contracts.company_id = companies.id ORDER BY contracts.end_date"; Now how would I output this in PHP? I tried this but kept getting an undefined error "Notice: Undefined index: contracts.id"... $sql_result = mysql_query($sql,$connection) or die ("Fail."); if(mysql_num_rows($sql_result) > 0){ while($row = mysql_fetch_array($sql_result)) { $contract_id = stripslashes($row['contracts.id']); $job_number = stripslashes($row['jobs.job_number']); $company_name = stripslashes($row['companies.name']); ?> <tr id="<?=$contract_id?>"> <td><?=$job_number?></td> <td><?=$company_name?></td> </tr> <? } }else{ echo "No records found"; } Any help is appreciated.

    Read the article

  • Perl TCP Server handling multiple Client connections

    - by Matt
    I'll preface this by saying I have minimal experience with both Perl and Socket programming, so I appreciate any help I can get. I have a TCP Server which needs to handle multiple Client connections simultaneously and be able to receive data from any one of the Clients at any time and also be able to send data back to the Clients based on information it's received. For example, Client1 and Client2 connect to my Server. Client2 sends "Ready", the server interprets that and sends "Go" to Client1. The following is what I have written so far: my $sock = new IO::Socket::INET { LocalHost => $host, // defined earlier in code LocalPort => $port, // defined earlier in code Proto => 'tcp', Listen => SOMAXCONN, Reuse => 1, }; die "Could not create socket $!\n" unless $sock; while ( my ($new_sock,$c_addr) = $sock->accept() ) { my ($client_port, $c_ip) = sockaddr_in($c_addr); my $client_ipnum = inet_ntoa($c_ip); my $client_host = ""; my @threads; print "got a connection from $client_host", "[$client_ipnum]\n"; my $command; my $data; while ($data = <$new_sock>) { push @threads, async \&Execute, $data; } } sub Execute { my ($command) = @_; // if($command) = "test" { // send "go" to socket1 print "Executing command: $command\n"; system($command); } I know both of my while loops will be blocking and I need a way to implement my accept command as a thread, but I'm not sure the proper way of writing it.

    Read the article

  • Flash browser game - HTTP + PHP vs Socket + Something else

    - by Maurycy Zarzycki
    I am developing a non-real time browser RPG game (think Kingdom of Loathing) which would be played from within a Flash app. At first I just wanted to make the communication with server using simply URLLoader to tell PHP what I am doing, and using $_SESSION to store data needed in-between request. I wonder if it wouldn't be better to base it on a socket connection, an app residing on a server written in Java or Python. The problem is I have never ever written such an app so I have no idea how much I'd have to "shift" my thoughts from simple responding do request (like PHP) to continuously working application. I won't hide I am also concerned about the memory and CPU usage of such Server app, when for example there would be hundreds of users connected. I've done some research. I have tried to do some research, but thanks to my nil knowledge on the sockets subject I haven't found anything helpful. So, considering the fact I don't need real time data exchange, will it be wise to develop the server side part as socket server, not in plain ol' PHP?

    Read the article

  • iPhone Custom CA certificate for an application which uses NSURLConnection?

    - by jr
    I have an application which is communicating with many different sites and each site has its own SSL certificate signed by our own internal CA. Doing this prevents us the need from purchasing SSL certificates for each site (hundreds or thousands) and is more secure then using a wildcard certificate with a shared key on each of those sites. So, basically using a CA certificate is the only way. Right now, I have a mobileprovision file which will install the CA certificate as a profile on the phone. When our iPhone application launches if it gets an SSL Certificate error it redirects to a this mobile provision file via Safari and the user will be prompted to install the CA. The problem is that I am concerned that the Apple AppStore might deny my app for doing this (Just some feedback from other developers at this point), and I wanted to research other ways to accomplish this. Basically what I need to accomplish is allow an SSL connection which will verify against a custom CA certificate which will be embedded in my application. This will make the CA certificate active for only the calls I make. I am using the standard NSURLConnection methods in order to communicate with the service. Is this possible? Can someone show me how to load the CA (what form PEM?) and add it to the list of trusted CA certificates for my application? If that is not possible what other options do I have? Just trusting all certificates isn't really any option, we want to prevent man in the middle attacks and only trust our CA issued certificates. Thanks!

    Read the article

  • Drupal 7 configuration error with Postgresql in Mac OS 10.6.5

    - by Sam
    I am trying to configure Drupal 7 with Postgres. At the database setup step, I get the following error. Warning: PDO::_construct(): [2002] No such file or directory (trying to connect via unix:///var/mysql/mysql.sock) in DatabaseConnection-_construct() (line 300 of /Users/shamod/Sites/drupal/7/includes/database/database.inc). In order for Drupal to work, and to continue with the installation process, you must resolve all issues reported below. For more help with configuring your database server, see the installation handbook. If you are unsure what any of this means you should probably contact your hosting provider. Failed to connect to your database server. The server reports the following message: SQLSTATE[HY000] [2002] No such file or directory. Is the database server running? Does the database exist, and have you entered the correct database name? Have you entered the correct username and password? Have you entered the correct database hostname? NOTE: I am trying to connect to Postgresql but it fails on var/mysql/mysql.sock error. I have setup the database connection string in settings.php for Postgresql. It still does not work. Any idea?

    Read the article

  • EF in a UserControl can't see the app.config?

    - by Sven
    I just created a user control. This control also makes use of my static Entity Framework class to load two comboboxes. All is well and runs without a problem. Design and runtime are working. Then when I stop the application all the forms that contain my UserControl don't work any more in design time. I just see two errors: Error1: The specified named connection is either not found in the configuration, not intended to be used with the EntityClient provider, or not valid. Error 2: The variable ccArtikelVelden is either undeclared or was never assigned. (ccArtikelVelde is my UserControl) Runtime everything is still working My static EF Repositoy class: public class BSManagerData { private static BSManagerEntities _entities; public static BSManagerEntities Entities { get { if (_entities == null) _entities = new BSManagerEntities(); return _entities; } set { _entities = value; } } } Some logic happening in my UserControl to load the data in the comboboxes: private void LaadCbx() { cbxCategorie.DataSource = (from c in BSManagerData.Entities.Categories select c).ToList(); cbxCategorie.DisplayMember = "Naam"; cbxCategorie.ValueMember = "Id"; } private void cbxCategorie_SelectedIndexChanged(object sender, EventArgs e) { cbxFabrikant.DataSource = from f in BSManagerData.Entities.Fabrikants where f.Categorie.Id == ((Categorie)cbxCategorie.SelectedItem).Id select f; cbxFabrikant.DisplayMember = "Naam"; cbxFabrikant.ValueMember = "Id"; } The only way to make my forms work again, design time, is to comment out the EF part in the UserControl (see above) and rebuild. It's very strange, everything is in the same assembly, same namespace (for the sake of simplicity). Anyone an idea?

    Read the article

  • What legal disclaimer do you use?

    - by Egwor
    I'm working on some code at the moment, but I was wondering what legal disclaimers you have? This is for some work that I'm providing to a friend for free. This isn't open source since there's competitive advantage in the internal workings of the program. I was thinking of something like: Copyright 2008 Egwor.com All rights reserved. Except as contained in this notice, the name(s) of the above copyright holders shall not be used in advertising or otherwise to promote the sale, use or other dealings in this Software without prior written authorization. THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE The above copyright notice and this permission notice shall be included in all copies or substantial portions of the Software. What do you use?

    Read the article

  • "Thread was being aborted" 0n large dataset

    - by Donaldinio
    I am trying to process 114,000 rows in a dataset (populated from an oracle database). I am hitting an error at around the 600 mark - "Thread was being aborted". All I am doing is reading the dataset, and I still hit the issue. Is this too much data for a dataset? It seems to load into the dataset ok though. I welcome any better ways to process this amount of data. rootTermsTable = entKw.GetRootKeywordsByCategory(catID); for (int k = 0; k < rootTermsTable.Rows.Count; k++) { string keywordID = rootTermsTable.Rows[k]["IK_DBKEY"].ToString(); ... } public DataTable GetKeywordsByCategory(string categoryID) { DbProviderFactory provider = DbProviderFactories.GetFactory(connectionProvider); DbConnection con = provider.CreateConnection(); con.ConnectionString = connectionString; DbCommand com = provider.CreateCommand(); com.Connection = con; com.CommandText = string.Format("Select * From icm_keyword WHERE (IK_IC_DBKEY = {0})",categoryID); com.CommandType = CommandType.Text; DataSet ds = new DataSet(); DbDataAdapter ad = provider.CreateDataAdapter(); ad.SelectCommand = com; con.Open(); ad.Fill(ds); con.Close(); DataTable dt = new DataTable(); dt = ds.Tables[0]; return dt; //return ds.Tables[0].DefaultView; }

    Read the article

  • android populating gridivew from a url string

    - by user1685991
    I am building an android application in which i am trying to read data from a url and want to display the data in a gridview. But i have some problem or dont understand to how to display the array list on grdiview. Here is my code for reading data from php url ArrayList<NameValuePair> nameValuePairs = new ArrayList<NameValuePair>(); //http post try{ HttpClient httpclient = new DefaultHttpClient(); HttpPost httppost = new HttpPost("http://sml.com.pk/a/smldb.php"); httppost.setEntity(new UrlEncodedFormEntity(nameValuePairs)); HttpResponse response = httpclient.execute(httppost); HttpEntity entity = response.getEntity(); is = entity.getContent(); }catch(Exception e){ Log.e("log_tag", "Error in http connection"+e.toString()); } //convert response to string try{ BufferedReader reader = new BufferedReader(new InputStreamReader(is,"iso-8859-1"),8); sb = new StringBuilder(); sb.append(reader.readLine() + "\n"); String line="0"; while ((line = reader.readLine()) != null) { sb.append(line + "\n"); } is.close(); result=sb.toString(); }catch(Exception e){ Log.e("log_tag", "Error converting result "+e.toString()); } //paring data double des; double value; try{ jArray = new JSONArray(result); JSONObject json_data=null; for(int i=0;i<jArray.length();i++){ json_data = jArray.getJSONObject(i); LAT=json_data.getDouble("TITLE"); LANG=json_data.getDouble("A"); } } catch(JSONException e1){ Toast.makeText(getBaseContext(), "No Vehicles Found" ,Toast.LENGTH_LONG).show(); } catch (ParseException e1) { e1.printStackTrace(); } Here TITLE and A are my two columns of DB Table and i want to display them on gridview please any one help me to do this according to my current code. Here is my live url for data string http://sml.com.pk/a/smldb.php

    Read the article

  • how to connect to MSSQL using activerecord, JDBC, JTDS and Integrated Security

    - by Rob
    As per the above, I've tried: establish_connection(:adapter => "jdbcmssql", :url => "jdbc:jtds:sqlserver://myserver:1433/mydatabase;domain='mynetwork';", :username => 'user', :password=>'pass' ) establish_connection(:adapter => "jdbcmssql", :url => 'jdbc:jtds:sqlserver://myserver:1433/mydatabase;domain="mynetwork";user="mynetwork\user"' ) establish_connection(:adapter => "jdbcmssql", :url => "jdbc:jtds:sqlserver://myserver:1433/mydatabase;domain='mynetwork';", :username=>'user' ) establish_connection(:adapter => "jdbcmssql", :url => "jdbc:jtds:sqlserver://myserver:1433/mydatabase;domain='mynetwork';integratedSecurity='true'", :username=>'user' ) .. and various other combinations. Each time I get: net/sourceforge/jtds/jdbc/SQLDiagnostic.java:368:in `addDiagnostic': java.sql.SQLException: Login failed for user ''. The user is not associated with a trusted SQL Server connection. (NativeException) Any tips? Thanks, activerecord (2.3.5) activerecord-jdbc-adapter (0.9.6) activerecord-jdbcmssql-adapter (0.9.6) jdbc-jtds (1.2.5) jruby 1.4.0 (ruby 1.8.7 patchlevel 174) (2009-11-02 69fbfa3) (Java HotSpot(TM) Client VM 1.6.0_18) [x86-java]

    Read the article

  • Listening Port Permanently. if file is on my stream, Get file. How to?

    - by Phsika
    i writed 2 client and server program. client dend file also server listen port and than get file.But i need My server App must listen on 51124 port permanently. if any file on my stream, show my message "there is a file on your stream" and than show me savefile dialog. But my server app in "Infinite loop". 1) listen 51124 port every time 2) do i have a file on my stream, show me a messagebox. private void Form1_Load(object sender, EventArgs e) { TcpListener Dinle = new TcpListener(51124); try { Dinle.Start(); Socket Baglanti = Dinle.AcceptSocket(); if (!Baglanti.Connected) { MessageBox.Show("No Connection!"); } else { while (true) { byte[] Dizi = new byte[250000]; Baglanti.Receive(Dizi, Dizi.Length, 0); string Yol; saveFileDialog1.Title = "Save File"; saveFileDialog1.ShowDialog(); Yol = saveFileDialog1.FileName; FileStream Dosya = new FileStream(Yol, FileMode.Create); Dosya.Write(Dizi, 0, Dizi.Length - 20); Dosya.Close(); listBox1.Items.Add("dosya indirildi"); listBox1.Items.Add("Dosya Boyutu=" + Dizi.Length.ToString()); listBox1.Items.Add("Indirilme Tarihi=" + DateTime.Now); listBox1.Items.Add("--------------------------------"); } } } catch (Exception) { throw; } } My Algorithm: if(AnyFileonStream()==true) { GetFile() //Also continue to listening 51124 port... } How can i do that?

    Read the article

  • Django Many-to-Many Question

    - by DZ
    My questions seems like a common problem that when I have seen any questions on it is never really asked right or not answered. So Im going to try to get the question right, and maybe someone knows how to resolve the issue, or correct my understanding. The problem: When you have a many-to-many relation ship (related_name not through) and you are trying to use the admin interface you are required to input one of the rleationships even though it does not have to exsist for you to create the first entry. Meaning you have to assign a group to an event to create the group. Wow that sounds complicated. So I can see why the question is not getting answered. Lets try the non code explanation example... First and important versions: Django 1.1.1 Phython 2.6 So I have a model where I created a many-to-many realtionship and Im using the related_name Im creating an app that is an event organizer, for simplicty lets say events although they could be anytype). For this first post Im going to stay away from the code and just try to explain. A few keys: (explaining comment) ** - many-to-many So in the model we have 1) The Main Event (this is main model) 2) Groups (link to events and their can be many events for a group) a) Events** I have simplified this example a little becuase I recognize that what does it matter. Just create the event first... But there are specific varations where that will not work. What the many-to-many related_name does it created another table with the indecies of the two other tables. Nothing says that this extra table HAS to be populated. Becuase if I look in the database and work within myPHPadmin I can create a group with out registering an event, since the connection between the two is a seperate table the DB does not care. How do I make the admin interface this realize it? Ok I know thats a lot so I hope I have explained it clearly. Thank you anyone for your comments/thoughts/advice

    Read the article

  • Map inheritance from generic class in Linq To SQL

    - by Ksenia Mukhortova
    Hi everyone, I'm trying to map my inheritance hierarchy to DB using Linq to SQL: Inheritance is like this, classes are POCO, without any LINQ to SQL attributes: public interface IStage { ... } public abstract class SimpleStage<T> : IStage where T : Process { ... } public class ConcreteStage : SimpleStage<ConcreteProcess> { ... } Here is the mapping: <Database Name="NNN" xmlns="http://schemas.microsoft.com/linqtosql/mapping/2007"> <Table Name="dbo.Stage" Member="Stage"> <Type Name="BusinessLogic.Domain.IStage"> <Column Name="ID" Member="ID" DbType="Int NOT NULL IDENTITY" IsPrimaryKey="true" IsDbGenerated="true" AutoSync="OnInsert" /> <Column Name="StageType" Member="StageType" IsDiscriminator="true" /> <Type Name="BusinessLogic.Domain.SimpleStage" IsInheritanceDefault="true"> <Type Name="BusinessLogic.Domain.ConcreteStage" IsInheritanceDefault="true" InheritanceCode="1"/> </Type> </Type> </Table> </Database> In the runtime I get error: System.InvalidOperationException was unhandled Message="Mapping Problem: Cannot find runtime type for type mapping 'BusinessLogic.Domain.SimpleStage'." Neither specifying SimpleStage, nor SimpleStage<T> in mapping file helps - runtime keeps producing different types of errors. DC is created like this: StreamReader sr = new StreamReader(@"MappingFile.map"); XmlMappingSource mapping = XmlMappingSource.FromStream(sr.BaseStream); DataContext dc = new DataContext(@"connection string", mapping); If Linq to SQL doesn't support this, could you, please, advise some other ORM, which does. Thanks in advance, Regards! Ksenia

    Read the article

  • Android: Gzip/Http supported by default?

    - by OneWorld
    I am using the code shown below to get Data from our server where Gzip is turned on. Does my Code already support Gzip (maybe this is already done by android and not by my java program) or do I have to add/change smth.? How can I check that it's using Gzip? For my opionion the download is kinda slow. private static InputStream OpenHttpConnection(String urlString) throws IOException { InputStream in = null; int response = -1; URL url = new URL(urlString); URLConnection conn = url.openConnection(); if (!(conn instanceof HttpURLConnection)) throw new IOException("Not an HTTP connection"); try { HttpURLConnection httpConn = (HttpURLConnection) conn; httpConn.setAllowUserInteraction(false); httpConn.setInstanceFollowRedirects(true); httpConn.setRequestMethod("GET"); httpConn.connect(); response = httpConn.getResponseCode(); if (response == HttpURLConnection.HTTP_OK) { in = httpConn.getInputStream(); if(in == null) throw new IOException("No data"); } } catch (Exception ex) { throw new IOException("Error connecting"); } return in; }

    Read the article

  • NHibernate + Cannot insert the value NULL into...

    - by mybrokengnome
    I've got a MS-SQL database with a table created with this code CREATE TABLE [dbo].[portfoliomanager]( [idPortfolioManager] [int] NOT NULL PRIMARY KEY IDENTITY, [name] [varchar](45) NULL ) so that idPortfolioManager is my primary key and also auto-incrementing. Now on my Windows WPF application I'm using NHibernate to help with adding/updating/removing/etc. data from the database. Here is the class that should be connecting to the portfoliomanager table namespace PortfolioManager { [Class(Table="portfoliomanager",NameType=typeof(PortfolioManagerClass))] public class PortfolioManagerClass { [Id(Name = "idPortfolioManager")] [Generator(1, Class = "identity")] public virtual int idPortfolioManager { get; set; } [NHibernate.Mapping.Attributes.Property(Name = "name")] public virtual string name { get; set; } public PortfolioManagerClass() { } } } and some short code to try and insert something PortfolioManagerClass portfolio = new PortfolioManagerClass(); Portfolio.name = "Brad's Portfolios"; The problem is, when I try running this, I get this error: {System.Data.SqlClient.SqlException: Cannot insert the value NULL into column 'idPortfolioManager', table 'PortfolioManagementSystem.dbo.portfoliomanager'; column does not allow nulls. INSERT fails. The statement has been terminated... with an outer exception of {"could not insert: [PortfolioManager.PortfolioManagerClass][SQL: INSERT INTO portfoliomanager (name) VALUES (?); select SCOPE_IDENTITY()]"} I'm hoping this is the last error I'll have to solve with NHibernate just to get it to do something, it's been a long process. Just as a note, I've also tried setting Class="native" and unsaved-value="0" with the same error. Thanks! Edit: Ok removing the 1, from Generator actually allows the program to run (not sure why that was even in the samples I was looking at) but it actually doesn't get added to the database. I logged in to the server and ran the sql server profiler tool and I never see the connection coming through or the SQL its trying to run, but NHibernate isn't throwing an error anymore. Starting to think it would be easier to just write SQL statements myself :(

    Read the article

  • How should I implement simple caches with concurrency on Redis?

    - by solublefish
    Background I have a 2-tier web service - just my app server and an RDBMS. I want to move to a pool of identical app servers behind a load balancer. I currently cache a bunch of objects in-process. I hope to move them to a shared Redis. I have a dozen or so caches of simple, small-sized business objects. For example, I have a set of Foos. Each Foo has a unique FooId and an OwnerId. One "owner" may own multiple Foos. In a traditional RDBMS this is just a table with an index on the PK FooId and one on OwnerId. I'm caching this in one process simply: Dictionary<int,Foo> _cacheFooById; Dictionary<int,HashSet<int>> _indexFooIdsByOwnerId; Reads come straight from here, and writes go here and to the RDBMS. I usually have this invariant: "For a given group [say by OwnerId], the whole group is in cache or none of it is." So when I cache miss on a Foo, I pull that Foo and all the owner's other Foos from the RDBMS. Updates make sure to keep the index up to date and respect the invariant. When an owner calls GetMyFoos I never have to worry that some are cached and some aren't. What I did already The first/simplest answer seems to be to use plain ol' SET and GET with a composite key and json value: SET( "ServiceCache:Foo:" + theFoo.Id, JsonSerialize(theFoo)); I later decided I liked: HSET( "ServiceCache:Foo", theFoo.FooId, JsonSerialize(theFoo)); That lets me get all the values in one cache as HVALS. It also felt right - I'm literally moving hashtables to Redis, so perhaps my top-level items should be hashes. This works to first order. If my high-level code is like: UpdateCache(myFoo); AddToIndex(myFoo); That translates into: HSET ("ServiceCache:Foo", theFoo.FooId, JsonSerialize(theFoo)); var myFoos = JsonDeserialize( HGET ("ServiceCache:FooIndex", theFoo.OwnerId) ); myFoos.Add(theFoo.OwnerId); HSET ("ServiceCache:FooIndex", theFoo.OwnerId, JsonSerialize(myFoos)); However, this is broken in two ways. Two concurrent operations can read/modify/write at the same time. The latter "wins" the final HSET and the former's index update is lost. Another operation could read the index in between the first and second lines. It would miss a Foo that it should find. So how do I index properly? I think I could use a Redis set instead of a json-encoded value for the index. That would solve part of the problem since the "add-to-index-if-not-already-present" would be atomic. I also read about using MULTI as a "transaction" but it doesn't seem like it does what I want. Am I right that I can't really MULTI; HGET; {update}; HSET; EXEC since it doesn't even do the HGET before I issue the EXEC? I also read about using WATCH and MULTI for optimistic concurrency, then retrying on failure. But WATCH only works on top-level keys. So it's back to SET/GET instead of HSET/HGET. And now I need a new index-like-thing to support getting all the values in a given cache. If I understand it right, I can combine all these things to do the job. Something like: while(!succeeded) { WATCH( "ServiceCache:Foo:" + theFoo.FooId ); WATCH( "ServiceCache:FooIndexByOwner:" + theFoo.OwnerId ); WATCH( "ServiceCache:FooIndexAll" ); MULTI(); SET ("ServiceCache:Foo:" + theFoo.FooId, JsonSerialize(theFoo)); SADD ("ServiceCache:FooIndexByOwner:" + theFoo.OwnerId, theFoo.FooId); SADD ("ServiceCache:FooIndexAll", theFoo.FooId); EXEC(); //TODO somehow set succeeded properly } Finally I'd have to translate this pseudocode into real code depending how my client library uses WATCH/MULTI/EXEC; it looks like they need some sort of context to hook them together. All in all this seems like a lot of complexity for what has to be a very common case; I can't help but think there's a better, smarter, Redis-ish way to do things that I'm just not seeing. How do I lock properly? Even if I had no indexes, there's still a (probably rare) race condition. A: HGET - cache miss B: HGET - cache miss A: SELECT B: SELECT A: HSET C: HGET - cache hit C: UPDATE C: HSET B: HSET ** this is stale data that's clobbering C's update. Note that C could just be a really-fast A. Again I think WATCH, MULTI, retry would work, but... ick. I know in some places people use special Redis keys as locks for other objects. Is that a reasonable approach here? Should those be top-level keys like ServiceCache:FooLocks:{Id} or ServiceCache:Locks:Foo:{Id}? Or make a separate hash for them - ServiceCache:Locks with subkeys Foo:{Id}, or ServiceCache:Locks:Foo with subkeys {Id} ? How would I work around abandoned locks, say if a transaction (or a whole server) crashes while "holding" the lock?

    Read the article

  • Audio Streaming Latency

    - by killianmcc
    I'm writing a UDP local area network video chat system and have got the video and audio streams working. However I'm experiencing a little latency (about half a second) in the audio and was wondering what codecs would provide the least latency. I'm using NAudio (http://naudio.codeplex.com/) which provides me access to the following codecs for streaming; Speex Narrow Band (VBR) Speex Wide Band (16kHz)(VBR) Speex Ultra Wide Band (32kHz)(VBR) DSP Group TrueSpeech (8.5kbps) GSM 6.10 (13kbps) Microsoft ADPCM (32.8kbps) G.711 a-law (64kbps) G.722 16kHz (64kbps) G.711 mu-law (64kbps) PCM 8kHz 16 bit uncompressed (128kbps) I've tried them out and I'm not noticing much difference. Is there any others that I should download and try to reduce latency? I'm only going to be sending voice over the connection but I'm not really worried about quality or background noises too much. UPDATE I'm sending the audio in blocks like so; waveIn = new WaveIn(); waveIn.BufferMilliseconds = 50; waveIn.DeviceNumber = inputDeviceNumber; waveIn.WaveFormat = codec.RecordFormat; waveIn.DataAvailable += waveIn_DataAvailable; void waveIn_DataAvailable(object sender, WaveInEventArgs e) { if (connected) { byte[] encoded = codec.Encode(e.Buffer, 0, e.BytesRecorded); udpSender.Send(encoded, encoded.Length); } }

    Read the article

  • I need help solving a rather weird error in a WCF service.

    - by Moulde
    Hi.. I have a solution that contains three projects. A main project with my MVC app, a silverlight application and a (silverlight enabled) WCF service project. In my silverlight project i have made a Service Reference to my WCF service. And i pretty much got that working. In my WCF service i have a method that returns an Book object, which got some random fields like title, date etc. In the book class, i have a ICollection field that contains a list of events. The book class is generated using entity framework 4.0, and Lazy Loading is enabled. If i in my getBook(int id) method return a book with the events field not initialized, it works as a charm. But if i initialize the field, i'm getting this error. The server did not provide a meaningful reply; this might be caused by a contract mismatch, a premature session shutdown or an internal server error. I have a few ideas why that is happening, and while writing this i just got another one. The wcf service somehow threw away the reference to the event class. That would be very weird since i have a reference between my main mvc app (with the models) and my WCF service. Since i have enabled lazy loading in EF 4.0, i suspect that it may be the thing generating the error. But i'm not sure why that would be, because i'm not in any way accessing that field. I could understand that i may not be able to access the events field after i recive the object in my silverlight application since the connection between the book object and the entity framework is like broken. Did i mention that Lazy Loading is enabled on my EF instance? And there is no inner exception in the thrown exception. Thanks in advance. Malte Baden Hansen

    Read the article

  • What can cause a spontaneous EPIPE error without either end calling close() or crashing?

    - by Hongli
    I have an application that consists of two processes (let's call them A and B), connected to each other through Unix domain sockets. Most of the time it works fine, but some users report the following behavior: A sends a request to B. This works. A now starts reading the reply from B. B sends a reply to A. The corresponding write() call returns an EPIPE error, and as a result B close() the socket. However, A did not close() the socket, nor did it crash. A's read() call returns 0, indicating end-of-file. A thinks that B prematurely closed the connection. Users have also reported variations of this behavior, e.g.: A sends a request to B. This works partially, but before the entire request is sent A's write() call returns EPIPE, and as a result A close() the socket. However B did not close() the socket, nor did it crash. B reads a partial request and then suddenly gets an EOF. The problem is I cannot reproduce this behavior locally at all. I've tried OS X and Linux. The users are on a variety of systems, mostly OS X and Linux. Things that I've already tried and considered: Double close() bugs (close() is called twice on the same file descriptor): probably not as that would result in EBADF errors, but I haven't seen them. Increasing the maximum file descriptor limit. One user reported that this worked for him, the rest reported that it did not. What else can possibly cause behavior like this? I know for certain that neither A nor B close() the socket prematurely, and I know for certain that neither of them have crashed because both A and B were able to report the error. It is as if the kernel suddenly decided to pull the plug from the socket for some reason.

    Read the article

  • VisualSVN How to roll back the revision number ?

    - by Ita
    The company I work in has suffered a major server failure. During this failure the SVN Repository was lost. But there is still hope ! We have an old backup of the repository which I've managed to successfully restore using VisualSVN. The problem I'm facing now is that I can't update / commit pre-failure checkedout folders. The reason for this problem is that for instance: a local folder has a revision number of 2361, while the repository itself holds a revision number of 2290, which is older. Is there a way to deal with this issue ? Can I some how change the revision numbers on either the local copy or the server copy? A few points: I'm using TortoiseSVN 1.6.6. I can checkout folders from the repo and the connection is active. I've picked one of my folders and used the Relocate option on it. This helped me see that there is something wrong with the revision number I've experimented a bit with the merge option but this lead me now where special. (I'm open for suggestions ) Thank you for your time, Ita

    Read the article

  • Login fails when recreating database with Code First

    - by Mun
    I'm using ASP.NET Entity Framework's Code First to create my database from the model, and the login seems to fail when the database needs to be recreated after the model changes. In Global.asax, I've got the following: protected void Application_Start() { Database.SetInitializer(new DropCreateDatabaseIfModelChanges<EntriesContext>()); // ... } In my controller, I've got the following: public ActionResult Index() { // This is just to force the database to be created var context = new EntriesContext(); var all = (from e in context.Entries select e).ToList(); } When the database doesn't exist, it is created with no problems. However, when I make a change to the model, rebuild and refresh, I get the following error: Login failed for user 'sa'. My connection string looks like this: <add name="EntriesContext" connectionString="Server=(LOCAL);Database=MyDB;User Id=sa;Password=password" providerName="System.Data.SqlClient" /> The login definitely works as I can connect to the server and the database from Management Studio using these credentials. If I delete the database manually, everything works correctly and the database is recreated as expected with the schema reflecting the changes made to the model. It seems like either the password or access to the database is being lost. Is there something else I need to do to get this working?

    Read the article

  • Advice on setting up a central db with master tables for web apps

    - by Dragn1821
    I'm starting to write more and more web applications for work. Many of these web applications need to store the same types of data, such as location. I've been thinking that it may be better to create a central db and store these "master" tables there and have each applicaiton access them. I'm not sure how to go about this. Should I create tables in my application's db to copy the data from the master table and store in the app's table (for linking with other app tables using foreign keys)? Should I use something like a web service to read the data from the master table instead of firing up a new db connection in my app? Should I forget this idea and just store the data within my app's db? I would like to have data such as the location central so I can go to one table and add a new location and the next time someone needs to select a location from one of the apps, the new one would be there. I'm using ASP.NET MVC 1.0 to build the web apps and SQL 2005 as the db. Need some advice... Thanks!

    Read the article

< Previous Page | 646 647 648 649 650 651 652 653 654 655 656 657  | Next Page >