Search Results

Search found 1302 results on 53 pages for 'async'.

Page 4/53 | < Previous Page | 1 2 3 4 5 6 7 8 9 10 11 12  | Next Page >

• Xenserver 5.5 U2 a bit unstable with an unstable W2003 VM

  - by twistedbrain

  In the last week I had to reboot the host system twice and the second one by means of the power button. The system is a Dell PE 6950 (4 Opteron dual core, 2,8 Ghz, 16 GB RAM, 900 GB disk in a RAID 10 array composed by 4 450GB 15000 rpm disks) with XenServer 5.5 U2. We're installing it and at now there are working in production a 2003 32 bit Windows server VM with 2 GB RAM, 3 vcpu and about 200 GB disk in 4 partition (12 GB boot, 20 GB program, 80 GB user data, 80 GB other data). The first time I was compressing many Windows 2003 folders (some tens GB by means of W2003 compressed folder option) from a Windows remote console and some hours before my colleague installed Backup Exec agent that was alredy installed and that required a reboot (that was pending). The console stopped responding, it was no more possible to connect by means of remote console or by means of the console of the XenCentre, it was still possible from the network to use the shared folder of the VM and the programs on it (2 db and a GIS program), but the print server didn't work any more and I couldn't give remote reboot from other domain controller hosts. I couldn't stop the virtual machine neither from the XenCentre, neither from the command line of the host also forcing the reboot. I had to reboot the host server. Yesterday it has been worst. I installed a template of another VM, CentOS 5.3 and then, put the DVD in the drive of the host. Then, before the install and after the boot I checked for defect the DVD and the W2003 VM began to respond slowly (I was connected by means of an administration remote console) the task manager showed only mid or low load, it is, only the first of the 3 vcpu was loaded (about 70%), while the other two were about at 20% and also the disk I/O was not so heavy. Then the users were not so happy because they couldn't any more use the MS word docs on the server. I immediately stopped the check of the DVD (to do that I had to force the stop of such Centos 5.3 VM), then some users could again use their docs, but other had still problems, so I decided to reboot the VM, but it doesn't stopped, neither from XenCenter, neither from command line, neither forcing the reboot. Then I tried to reboot of the host, but it didn't worked, neither from the XenCentre, neither from the host prompt (shutdown -r now as root: it told that it was shutting down, but then it didn't did that). So I had to power off by means of the power button of the server (before I tried some Magic SyS REQ, but I saw that Xen isn't compiled with this option enabled). What could you suggest about my problem, what can I look, search and see? In the W2003 VM logs there are no errors or warning to explain what happened. Some more exciting, amusing and inspiring words of poetry (the facts happened around 11 am): \# egrep -i 'err|warning' xensource.log [20100219 10:32:05.597|debug|culo|6301 unix-RPC|VBD.plug R:c81bcda701f6|xenops] watch: watching xenstore paths: [ /xapi/0/frontend/vbd/51712/hotplug; /local/domain/0/backend/vbd/0/51712/tapdisk-error ] with timeout 1200.000000 seconds [20100219 10:32:05.597|debug|culo|6301 unix-RPC|VBD.plug R:c81bcda701f6|xenops] watch: fired on /local/domain/0/backend/vbd/0/51712/tapdisk-error [20100219 10:32:14.314|debug|culo|6335 unix-RPC|VBD.unplug R:9258f54578d6|xenops] watch: watching xenstore paths: [ /local/domain/0/backend/vbd/0/51712/shutdown-done; /local/domain/0/error/device/vbd/51712/error ] with timeout 1200.000000 seconds [20100219 10:32:14.337|debug|culo|6335 unix-RPC|VBD.unplug R:9258f54578d6|xenops] xenstore-rm /local/domain/0/error/backend/vbd/0 [20100219 10:32:14.337|debug|culo|6335 unix-RPC|VBD.unplug R:9258f54578d6|xenops] xenstore-rm /local/domain/0/error/device/vbd/51712 [20100219 10:32:14.338|debug|culo|6335 unix-RPC|VBD.unplug R:9258f54578d6|xenops] watch: fired on /local/domain/0/error/device/vbd/51712/error [20100219 10:53:48.903|debug|culo|6418|Async.VM.hard_shutdown R:88d2095678f7|helpers] Ignoring exception: INTERNAL_ERROR: [ Xb.Noent ] while Vmops.destroy_domain: Destroying domid 14 guest session [20100219 10:53:52.048|debug|culo|6418|Async.VM.hard_shutdown R:88d2095678f7|xenops] xenstore-rm /local/domain/0/error/backend/tap/14 [20100219 10:53:52.048|debug|culo|6418|Async.VM.hard_shutdown R:88d2095678f7|xenops] xenstore-rm /local/domain/14/error/device/vbd/51744 [20100219 10:53:52.085|debug|culo|6418|Async.VM.hard_shutdown R:88d2095678f7|xenops] xenstore-rm /local/domain/0/error/backend/tap/14 [20100219 10:53:52.086|debug|culo|6418|Async.VM.hard_shutdown R:88d2095678f7|xenops] xenstore-rm /local/domain/14/error/device/vbd/51728 [20100219 10:53:52.122|debug|culo|6418|Async.VM.hard_shutdown R:88d2095678f7|xenops] xenstore-rm /local/domain/0/error/backend/tap/14 [20100219 10:53:52.122|debug|culo|6418|Async.VM.hard_shutdown R:88d2095678f7|xenops] xenstore-rm /local/domain/14/error/device/vbd/51712 [20100219 10:53:52.127|debug|culo|6418|Async.VM.hard_shutdown R:88d2095678f7|xenops] xenstore-rm /local/domain/0/error/backend/vbd/14 [20100219 10:53:52.128|debug|culo|6418|Async.VM.hard_shutdown R:88d2095678f7|xenops] xenstore-rm /local/domain/14/error/device/vbd/51760 [20100219 10:53:52.496|debug|culo|6418|Async.VM.hard_shutdown R:88d2095678f7|xenops] Device.Vif.hard_shutdown about to blow away backend and error paths [20100219 10:53:52.497|debug|culo|6418|Async.VM.hard_shutdown R:88d2095678f7|xenops] xenstore-rm /local/domain/0/error/backend/vif/14 [20100219 10:53:52.497|debug|culo|6418|Async.VM.hard_shutdown R:88d2095678f7|xenops] xenstore-rm /local/domain/14/error/device/vif/0 [20100219 10:53:53.385|debug|culo|6418|Async.VM.hard_shutdown R:88d2095678f7|xenops] Device.Vif.hard_shutdown about to blow away backend and error paths [20100219 10:53:53.386|debug|culo|6418|Async.VM.hard_shutdown R:88d2095678f7|xenops] xenstore-rm /local/domain/0/error/backend/vif/14 [20100219 10:53:53.386|debug|culo|6418|Async.VM.hard_shutdown R:88d2095678f7|xenops] xenstore-rm /local/domain/14/error/device/vif/1 [20100219 10:53:53.389| warn|culo|6418|Async.VM.hard_shutdown R:88d2095678f7|hotplug] Warning, deleting 'vif' entry from /xapi/14/hotplug/vif/0 [20100219 10:53:53.391| warn|culo|6418|Async.VM.hard_shutdown R:88d2095678f7|hotplug] Warning, deleting 'vif' entry from /xapi/14/hotplug/vif/1 [20100219 11:20:49.766|debug|culo|6484|Async.VM.clean_shutdown R:78d3c3e28cb6|helpers] Ignoring exception: INTERNAL_ERROR: [ Xb.Noent ] while Vmops.destroy_domain: Destroying domid 11 guest session [20100219 11:20:50.339|debug|culo|6484|Async.VM.clean_shutdown R:78d3c3e28cb6|xenops] xenstore-rm /local/domain/0/error/backend/tap/11 [20100219 11:20:50.339|debug|culo|6484|Async.VM.clean_shutdown R:78d3c3e28cb6|xenops] xenstore-rm /local/domain/11/error/device/vbd/832 [20100219 11:20:50.360|debug|culo|6484|Async.VM.clean_shutdown R:78d3c3e28cb6|xenops] xenstore-rm /local/domain/0/error/backend/tap/11 [20100219 11:20:50.360|debug|culo|6484|Async.VM.clean_shutdown R:78d3c3e28cb6|xenops] xenstore-rm /local/domain/11/error/device/vbd/768 [20100219 11:20:50.366|debug|culo|6484|Async.VM.clean_shutdown R:78d3c3e28cb6|xenops] xenstore-rm /local/domain/0/error/backend/vbd/11 [20100219 11:20:50.366|debug|culo|6484|Async.VM.clean_shutdown R:78d3c3e28cb6|xenops] xenstore-rm /local/domain/11/error/device/vbd/5696 [20100219 11:20:50.753|debug|culo|6484|Async.VM.clean_shutdown R:78d3c3e28cb6|xenops] Device.Vif.hard_shutdown about to blow away backend and error paths [20100219 11:20:50.754|debug|culo|6484|Async.VM.clean_shutdown R:78d3c3e28cb6|xenops] xenstore-rm /local/domain/0/error/backend/vif/11 [20100219 11:20:50.754|debug|culo|6484|Async.VM.clean_shutdown R:78d3c3e28cb6|xenops] xenstore-rm /local/domain/11/error/device/vif/1 [20100219 11:20:50.757| warn|culo|6484|Async.VM.clean_shutdown R:78d3c3e28cb6|hotplug] Warning, deleting 'vif' entry from /xapi/11/hotplug/vif/1 [20100219 11:28:13.803|debug|culo|6610 inet-RPC|Connection to VM console R:e9f8b76e8975|console] error: INTERNAL_ERROR: [ Unix.Unix_error(63, "connect", "") ]

  Read the article

• Async ignored on AJAX requests on Nginx server

  - by eComEvo

  Despite sending an async request to the server over AJAX, the server will not respond until the previous unrelated request has finished. The following code is only broken in this way on Nginx, but runs perfectly on Apache. This call will start a background process and it waits for it to complete so it can display the final result. $.ajax({ type: 'GET', async: true, url: $(this).data('route'), data: $('input[name=data]').val(), dataType: 'json', success: function (data) { /* do stuff */} error: function (data) { /* handle errors */} }); The below is called after the above, which on Apache requires 100ms to execute and repeats itself, showing progress for data being written in the background: checkStatusInterval = setInterval(function () { $.ajax({ type: 'GET', async: false, cache: false, url: '/process-status?process=' + currentElement.attr('id'), dataType: 'json', success: function (data) { /* update progress bar and status message */ } }); }, 1000); Unfortunately, when this script is run from nginx, the above progress request never even finishes a single request until the first AJAX request that sent the data is done. If I change the async to TRUE in the above, it executes one every interval, but none of them complete until that very first AJAX request finishes. Here is the main nginx conf file: #user nobody; worker_processes 1; #error_log logs/error.log; #error_log logs/error.log notice; #error_log logs/error.log info; #pid logs/nginx.pid; events { worker_connections 1024; } http { include mime.types; default_type application/octet-stream; server_names_hash_bucket_size 64; # configure temporary paths # nginx is started with param -p, setting nginx path to serverpack installdir fastcgi_temp_path temp/fastcgi; uwsgi_temp_path temp/uwsgi; scgi_temp_path temp/scgi; client_body_temp_path temp/client-body 1 2; proxy_temp_path temp/proxy; log_format main '$remote_addr - $remote_user [$time_local] "$request" ' '$status $body_bytes_sent "$http_referer" ' '"$http_user_agent" "$http_x_forwarded_for"'; #access_log logs/access.log main; # Sendfile copies data between one FD and other from within the kernel. # More efficient than read() + write(), since the requires transferring data to and from the user space. sendfile on; # Tcp_nopush causes nginx to attempt to send its HTTP response head in one packet, # instead of using partial frames. This is useful for prepending headers before calling sendfile, # or for throughput optimization. tcp_nopush on; # don't buffer data-sends (disable Nagle algorithm). Good for sending frequent small bursts of data in real time. tcp_nodelay on; types_hash_max_size 2048; # Timeout for keep-alive connections. Server will close connections after this time. keepalive_timeout 90; # Number of requests a client can make over the keep-alive connection. This is set high for testing. keepalive_requests 100000; # allow the server to close the connection after a client stops responding. Frees up socket-associated memory. reset_timedout_connection on; # send the client a "request timed out" if the body is not loaded by this time. Default 60. client_header_timeout 20; client_body_timeout 60; # If the client stops reading data, free up the stale client connection after this much time. Default 60. send_timeout 60; # Size Limits client_body_buffer_size 64k; client_header_buffer_size 4k; client_max_body_size 8M; # FastCGI fastcgi_connect_timeout 60; fastcgi_send_timeout 120; fastcgi_read_timeout 300; # default: 60 secs; when step debugging with XDEBUG, you need to increase this value fastcgi_buffer_size 64k; fastcgi_buffers 4 64k; fastcgi_busy_buffers_size 128k; fastcgi_temp_file_write_size 128k; # Caches information about open FDs, freqently accessed files. open_file_cache max=200000 inactive=20s; open_file_cache_valid 30s; open_file_cache_min_uses 2; open_file_cache_errors on; # Turn on gzip output compression to save bandwidth. # http://wiki.nginx.org/HttpGzipModule gzip on; gzip_disable "MSIE [1-6]\.(?!.*SV1)"; gzip_http_version 1.1; gzip_vary on; gzip_proxied any; #gzip_proxied expired no-cache no-store private auth; gzip_comp_level 6; gzip_buffers 16 8k; gzip_types text/plain text/css application/json application/x-javascript text/xml application/xml application/xml+rss text/javascript application/javascript; # show all files and folders autoindex on; server { # access from localhost only listen 127.0.0.1:80; server_name localhost; root www; # the following default "catch-all" configuration, allows access to the server from outside. # please ensure your firewall allows access to tcp/port 80. check your "skype" config. # listen 80; # server_name _; log_not_found off; charset utf-8; access_log logs/access.log main; # handle files in the root path /www location / { index index.php index.html index.htm; } #error_page 404 /404.html; # redirect server error pages to the static page /50x.html # error_page 500 502 503 504 /50x.html; location = /50x.html { root www; } # pass the PHP scripts to FastCGI server listening on 127.0.0.1:9100 # location ~ \.php$ { try_files $uri =404; fastcgi_pass 127.0.0.1:9100; fastcgi_index index.php; fastcgi_param SCRIPT_FILENAME $document_root$fastcgi_script_name; include fastcgi_params; } # add expire headers location ~* ^.+.(gif|ico|jpg|jpeg|png|flv|swf|pdf|mp3|mp4|xml|txt|js|css)$ { expires 30d; } # deny access to .htaccess files (if Apache's document root concurs with nginx's one) # deny access to git & svn repositories location ~ /(\.ht|\.git|\.svn) { deny all; } } # include config files of "enabled" domains include domains-enabled/*.conf; } Here is the enabled domain conf file: access_log off; access_log C:/server/www/test.dev/logs/access.log; error_log C:/server/www/test.dev/logs/error.log; # HTTP Server server { listen 127.0.0.1:80; server_name test.dev; root C:/server/www/test.dev/public; index index.php; rewrite_log on; default_type application/octet-stream; #include /etc/nginx/mime.types; # Include common configurations. include domains-common/location.conf; } # HTTPS server server { listen 443 ssl; server_name test.dev; root C:/server/www/test.dev/public; index index.php; rewrite_log on; default_type application/octet-stream; #include /etc/nginx/mime.types; # Include common configurations. include domains-common/location.conf; include domains-common/ssl.conf; } Contents of ssl.conf: # OpenSSL for HTTPS connections. ssl on; ssl_certificate C:/server/bin/openssl/certs/cert.pem; ssl_certificate_key C:/server/bin/openssl/certs/cert.key; ssl_session_timeout 5m; ssl_protocols SSLv3 TLSv1 TLSv1.1 TLSv1.2; ssl_ciphers HIGH:!aNULL:!MD5; ssl_prefer_server_ciphers on; # Pass the PHP scripts to FastCGI server listening on 127.0.0.1:9100 location ~ \.php$ { try_files $uri =404; fastcgi_param HTTPS on; fastcgi_pass 127.0.0.1:9100; fastcgi_index index.php; fastcgi_param SCRIPT_FILENAME $document_root$fastcgi_script_name; include fastcgi_params; } Contents of location.conf: # Remove trailing slash to please Laravel routing system. if (!-d $request_filename) { rewrite ^/(.+)/$ /$1 permanent; } location / { try_files $uri $uri/ /index.php?$query_string; } # We don't need .ht files with nginx. location ~ /(\.ht|\.git|\.svn) { deny all; } # Added cache headers for images. location ~* \.(png|jpg|jpeg|gif)$ { expires 30d; log_not_found off; } # Only 3 hours on CSS/JS to allow me to roll out fixes during early weeks. location ~* \.(js|css)$ { expires 3h; log_not_found off; } # Add expire headers. location ~* ^.+.(gif|ico|jpg|jpeg|png|flv|swf|pdf|mp3|mp4|xml|txt)$ { expires 30d; } # Pass the PHP scripts to FastCGI server listening on 127.0.0.1:9100 location ~ \.php$ { try_files $uri /index.php =404; fastcgi_index index.php; fastcgi_param SCRIPT_FILENAME $document_root$fastcgi_script_name; include fastcgi_params; fastcgi_pass 127.0.0.1:9100; } Any ideas where this is going wrong?

  Read the article

• Passing variable from main to Async class

  - by Bigflow

  Somehow, I can't get this done. This is all what I tried till now: Main: private String myState; public String getState() { return myState; } public void setState(String s) { myState = s; } Async: Main appState = ((Main)getApplicationContext()); String state = appState.getState(); Error: No enclosing instance of the type Main is accessible in scope Tried with Helper(Globals) class. public class Globals extends Application{ private String test= "1"; } Main: private Globals mGlobals; mGlobals = new Globals(); mGlobals.test = "2"; //Do Async thing Async: private Globals mGlobals; mGlobals = new Globals(); print mGlobals.test; // (result is 1, should be 2) Also something else, but don't remember good. Tried alot of things (backspace and del buttons are over-used :p ) But I can't get everything working. Async class doesn't have an activity. Code pasted: http://pastebin.com/ikcsdL1p

  Read the article

• Using Interlocked.Exchange(ref Enum, 1) to prevent re-entrancy [migrated]

  - by makerofthings7

  What options do I have for pending work that can't acquire a lock via the following sample? System.Threading.Interlocked.CompareExchange<TrustPointStatusEnum> (ref tp.TrustPointStatus, TrustPointStatusEnum.NotInitalized,TrustPointStatusEnum.Loading); Based on my research think I have the following options: I can use Threading.SpinWait (for very quick IO tasks) at the cost of CPU I can use Sleep() which has an unreliable wake up time I'm not sure of any other option, but what I want to make sure of is that all these options work with the .NET 4 async and await keywords, especially if I use Task to run them on a background thread

  Read the article

• C# 5 - asynch method callback with Task.ContinueWIth? [migrated]

  - by user1142433

  I have a method that pulls some HTML via the HttpClient like so: public static HttpClient web = new HttpClient(); public static async Task<string> GetHTMLDataAsync(string url) { string responseBodyAsText = ""; try { HttpResponseMessage response = await web.GetAsync(url); response.EnsureSuccessStatusCode(); responseBodyAsText = await response.Content.ReadAsStringAsync(); } catch (Exception e) { // Error handling } return responseBodyAsText; } I have another method that looks like so: private void HtmlReadComplete(string data) { // do something with the data } I would like to be able to call GetHTMLDataAsync and then have it call HtmlReadComplete on the UI thread when the html has been read. I naively thought this could somehow be done with something that looks like GetHTMLDataAsync(url).ContinueWith(HtmlReadComplete); But, I can't get the syntax correct, nor am I even sure that's the appropriate way to handle it. Thanks in advance!

  Read the article

• Implementing an async "read all currently available data from stream" operation

  - by Jon

  I recently provided an answer to this question: C# - Realtime console output redirection. As often happens, explaining stuff (here "stuff" was how I tackled a similar problem) leads you to greater understanding and/or, as is the case here, "oops" moments. I realized that my solution, as implemented, has a bug. The bug has little practical importance, but it has an extremely large importance to me as a developer: I can't rest easy knowing that my code has the potential to blow up. Squashing the bug is the purpose of this question. I apologize for the long intro, so let's get dirty. I wanted to build a class that allows me to receive input from a console's standard output Stream. Console output streams are of type FileStream; the implementation can cast to that, if needed. There is also an associated StreamReader already present to leverage. There is only one thing I need to implement in this class to achieve my desired functionality: an async "read all the data available this moment" operation. Reading to the end of the stream is not viable because the stream will not end unless the process closes the console output handle, and it will not do that because it is interactive and expecting input before continuing. I will be using that hypothetical async operation to implement event-based notification, which will be more convenient for my callers. The public interface of the class is this: public class ConsoleAutomator { public event EventHandler<ConsoleOutputReadEventArgs> StandardOutputRead; public void StartSendingEvents(); public void StopSendingEvents(); } StartSendingEvents and StopSendingEvents do what they advertise; for the purposes of this discussion, we can assume that events are always being sent without loss of generality. The class uses these two fields internally: protected readonly StringBuilder inputAccumulator = new StringBuilder(); protected readonly byte[] buffer = new byte[256]; The functionality of the class is implemented in the methods below. To get the ball rolling: public void StartSendingEvents(); { this.stopAutomation = false; this.BeginReadAsync(); } To read data out of the Stream without blocking, and also without requiring a carriage return char, BeginRead is called: protected void BeginReadAsync() { if (!this.stopAutomation) { this.StandardOutput.BaseStream.BeginRead( this.buffer, 0, this.buffer.Length, this.ReadHappened, null); } } The challenging part: BeginRead requires using a buffer. This means that when reading from the stream, it is possible that the bytes available to read ("incoming chunk") are larger than the buffer. Remember that the goal here is to read all of the chunk and call event subscribers exactly once for each chunk. To this end, if the buffer is full after EndRead, we don't send its contents to subscribers immediately but instead append them to a StringBuilder. The contents of the StringBuilder are only sent back whenever there is no more to read from the stream. private void ReadHappened(IAsyncResult asyncResult) { var bytesRead = this.StandardOutput.BaseStream.EndRead(asyncResult); if (bytesRead == 0) { this.OnAutomationStopped(); return; } var input = this.StandardOutput.CurrentEncoding.GetString( this.buffer, 0, bytesRead); this.inputAccumulator.Append(input); if (bytesRead < this.buffer.Length) { this.OnInputRead(); // only send back if we 're sure we got it all } this.BeginReadAsync(); // continue "looping" with BeginRead } After any read which is not enough to fill the buffer (in which case we know that there was no more data to be read during the last read operation), all accumulated data is sent to the subscribers: private void OnInputRead() { var handler = this.StandardOutputRead; if (handler == null) { return; } handler(this, new ConsoleOutputReadEventArgs(this.inputAccumulator.ToString())); this.inputAccumulator.Clear(); } (I know that as long as there are no subscribers the data gets accumulated forever. This is a deliberate decision). The good This scheme works almost perfectly: Async functionality without spawning any threads Very convenient to the calling code (just subscribe to an event) Never more than one event for each time data is available to be read Is almost agnostic to the buffer size The bad That last almost is a very big one. Consider what happens when there is an incoming chunk with length exactly equal to the size of the buffer. The chunk will be read and buffered, but the event will not be triggered. This will be followed up by a BeginRead that expects to find more data belonging to the current chunk in order to send it back all in one piece, but... there will be no more data in the stream. In fact, as long as data is put into the stream in chunks with length exactly equal to the buffer size, the data will be buffered and the event will never be triggered. This scenario may be highly unlikely to occur in practice, especially since we can pick any number for the buffer size, but the problem is there. Solution? Unfortunately, after checking the available methods on FileStream and StreamReader, I can't find anything which lets me peek into the stream while also allowing async methods to be used on it. One "solution" would be to have a thread wait on a ManualResetEvent after the "buffer filled" condition is detected. If the event is not signaled (by the async callback) in a small amount of time, then more data from the stream will not be forthcoming and the data accumulated so far should be sent to subscribers. However, this introduces the need for another thread, requires thread synchronization, and is plain inelegant. Specifying a timeout for BeginRead would also suffice (call back into my code every now and then so I can check if there's data to be sent back; most of the time there will not be anything to do, so I expect the performance hit to be negligible). But it looks like timeouts are not supported in FileStream. Since I imagine that async calls with timeouts are an option in bare Win32, another approach might be to PInvoke the hell out of the problem. But this is also undesirable as it will introduce complexity and simply be a pain to code. Is there an elegant way to get around the problem? Thanks for being patient enough to read all of this. Update: I definitely did not communicate the scenario well in my initial writeup. I have since revised the writeup quite a bit, but to be extra sure: The question is about how to implement an async "read all the data available this moment" operation. My apologies to the people who took the time to read and answer without me making my intent clear enough.

  Read the article

• Good Async pattern for sequential WebClient requests

  - by Omar Shahine

  Most of the code I've written in .NET to make REST calls have been synchronous. Since Silverlight on Windows Phone only supports Async WebClient and HttpWebRequest calls, I was wondering what a good async pattern is for a Class that exposes methods that make REST calls. For example, I have an app that needs to do the following. Login and get token Using token from #1, get a list of albums Using token from #1 get a list of categories etc my class exposes a few methods: Login() GetAlbums() GetCategories() since each method needs to call WebClient using Async calls what I need to do is essentially block calling Login till it returns so that I can call GetAlbums(). What is a good way to go about this in my class that exposes those methods?

  Read the article

• jQuery: 'async: false' Not Working With IE7 / IE6

  - by Norbert

  I created a simple tracking script which adds the users info to a database when the page is unloaded. It works on all browsers except IE7 and IE6. IE7 gives me errors, but I can't open the "debugger" because I'm using the standalone version (or at least that's what I think the problems is). I removed the async: false, from the script below and I didn't get any errors, but I need async set to false in order for the script to work. Any ideas? $(window).unload(function() { $.ajax({ type: "POST", async: false, url: "add.php", data: "ip=" + jIp + "&date=" + jDate + "&time=" + jTime, }); }); Update: I got IE7 to display the error, kinda. When I click OK on the dialog on top, it closes both dialogs. Ugh!

  Read the article

• How do you keep code with continuations/callbacks readable?

  - by Heinzi

  Summary: Are there some well-established best-practice patterns that I can follow to keep my code readable in spite of using asynchronous code and callbacks? I'm using a JavaScript library that does a lot of stuff asynchronously and heavily relies on callbacks. It seems that writing a simple "load A, load B, ..." method becomes quite complicated and hard to follow using this pattern. Let me give a (contrived) example. Let's say I want to load a bunch of images (asynchronously) from a remote web server. In C#/async, I'd write something like this: disableStartButton(); foreach (myData in myRepository) { var result = await LoadImageAsync("http://my/server/GetImage?" + myData.Id); if (result.Success) { myData.Image = result.Data; } else { write("error loading Image " + myData.Id); return; } } write("success"); enableStartButton(); The code layout follows the "flow of events": First, the start button is disabled, then the images are loaded (await ensures that the UI stays responsive) and then the start button is enabled again. In JavaScript, using callbacks, I came up with this: disableStartButton(); var count = myRepository.length; function loadImage(i) { if (i >= count) { write("success"); enableStartButton(); return; } myData = myRepository[i]; LoadImageAsync("http://my/server/GetImage?" + myData.Id, function(success, data) { if (success) { myData.Image = data; } else { write("error loading image " + myData.Id); return; } loadImage(i+1); } ); } loadImage(0); I think the drawbacks are obvious: I had to rework the loop into a recursive call, the code that's supposed to be executed in the end is somewhere in the middle of the function, the code starting the download (loadImage(0)) is at the very bottom, and it's generally much harder to read and follow. It's ugly and I don't like it. I'm sure that I'm not the first one to encounter this problem, so my question is: Are there some well-established best-practice patterns that I can follow to keep my code readable in spite of using asynchronous code and callbacks?

  Read the article

• Understanding Async Methods in Web Service.

  - by Polaris

  Hello. I consume Java Service in my .NET appliaction. I have one question: When service serialize in .NET he also create Async methods. For example for GetPersons() method service create GetPersonsAsync() which is return void. In which cases I can use this Async methods and what the destination of these methods.

  Read the article

• Writing async service using cxf with java first approach

  - by user350712

  Hello I need to create a async webservice using cxf with java first approach. But i am unable to find any web resource/ website which tells me how to do this? Can you please tell how can I write a async webservice using CXF with java first approach? Thanks Shekhar

  Read the article

• Enum types, FlagsAttribute & Zero value – Part 2

  - by nmgomes

  In my previous post I wrote about why you should pay attention when using enum value Zero. After reading that post you are probably thinking like Benjamin Roux: Why don’t you start the enum values at 0x1? Well I could, but doing that I lose the ability to have Sync and Async mutually exclusive by design. Take a look at the following enum types: [Flags] public enum OperationMode1 { Async = 0x1, Sync = 0x2, Parent = 0x4 } [Flags] public enum OperationMode2 { Async = 0x0, Sync = 0x1, Parent = 0x2 } To achieve mutually exclusion between Sync and Async values using OperationMode1 you would have to operate both values: protected void CheckMainOperarionMode(OperationMode1 mode) { switch (mode) { case (OperationMode1.Async | OperationMode1.Sync | OperationMode1.Parent): case (OperationMode1.Async | OperationMode1.Sync): throw new InvalidOperationException("Cannot be Sync and Async simultaneous"); break; case (OperationMode1.Async | OperationMode1.Parent): case (OperationMode1.Async): break; case (OperationMode1.Sync | OperationMode1.Parent): case (OperationMode1.Sync): break; default: throw new InvalidOperationException("No default mode specified"); } } but this is a by design constraint in OperationMode2. Why? Simply because 0x0 is the neutral element for the bitwise OR operation. Knowing this singularity, replacing and simplifying the previous method, you get: protected void CheckMainOperarionMode(OperationMode2 mode) { switch (mode) { case (OperationMode2.Sync | OperationMode2.Parent): case (OperationMode2.Sync): break; case (OperationMode2.Parent): default: break; } This means that: if both Sync and Async values are specified Sync value always win (Zero is the neutral element for bitwise OR operation) if no Sync value specified, the Async method is used. Here is the final method implementation: protected void CheckMainOperarionMode(OperationMode2 mode) { if (mode & OperationMode2.Sync == OperationMode2.Sync) { } else { } } All content above prove that Async value (0x0) is useless from the arithmetic perspective, but, without it we lose readability. The following IF statements are logically equals but the first is definitely more readable: if (OperationMode2.Async | OperationMode2.Parent) { } if (OperationMode2.Parent) { } Here’s another example where you can see the benefits of 0x0 value, the default value can be used explicitly. <my:Control runat="server" Mode="Async,Parent"> <my:Control runat="server" Mode="Parent">

  Read the article

• nodejs async.waterfall method

  - by user1513388

  Update 2 Complete code listing var request = require('request'); var cache = require('memory-cache'); var async = require('async'); var server = '172.16.221.190' var user = 'admin' var password ='Passw0rd' var dn ='\\VE\\Policy\\Objects' var jsonpayload = {"Username": user, "Password": password} async.waterfall([ //Get the API Key function(callback){ request.post({uri: 'http://' + server +'/sdk/authorize/', json: jsonpayload, headers: {'content_type': 'application/json'} }, function (e, r, body) { callback(null, body.APIKey); }) }, //List the credential objects function(apikey, callback){ var jsonpayload2 = {"ObjectDN": dn, "Recursive": true} request.post({uri: 'http://' + server +'/sdk/Config/enumerate?apikey=' + apikey, json: jsonpayload2, headers: {'content_type': 'application/json'} }, function (e, r, body) { var dns = []; for (var i = 0; i < body.Objects.length; i++) { dns.push({'name': body.Objects[i].Name, 'dn': body.Objects[i].DN}) } callback(null, dns, apikey); }) }, function(dns, apikey, callback){ // console.log(dns) var cb = []; for (var i = 0; i < dns.length; i++) { //Retrieve the credential var jsonpayload3 = {"CredentialPath": dns[i].dn, "Pattern": null, "Recursive": false} console.log(dns[i].dn) request.post({uri: 'http://' + server +'/sdk/credentials/retrieve?apikey=' + apikey, json: jsonpayload3, headers: {'content_type': 'application/json'} }, function (e, r, body) { // console.log(body) cb.push({'cl': body.Classname}) callback(null, cb, apikey); console.log(cb) }); } } ], function (err, result) { // console.log(result) // result now equals 'done' }); Update: I'm building a small application that needs to make multiple HTTP calls to a an external API and amalgamates the results into a single object or array. e.g. Connect to endpoint and get auth key - pass auth key to step 2 Connect to endpoint using auth key and get JSON results - create an object containing summary results and pass to step 3. Iterate over passed object summary results and call API for each item in the object to get detailed information for each summary line Create a single JSON data structure that contains the summary and detail information. The original question below outlines what I've tried so far! Original Question: Will the async.waterfall method support multiple callbacks? i.e. Iterate over an array thats passed from a previous item in the chain, then invoke multiple http requests each of which would have their own callbacks. e.g, sync.waterfall([ function(dns, key, callback){ var cb = []; for (var i = 0; i < dns.length; i++) { //Retrieve the credential var jsonpayload3 = {"Cred": dns[i].DN, "Pattern": null, "Recursive": false} console.log(dns[i].DN) request.post({uri: 'http://' + vedserver +'/api/cred/retrieve?apikey=' + key, json: jsonpayload3, headers: {'content_type': 'application/json'} }, function (e, r, body) { console.log(body) cb.push({'cl': body.Classname}) callback(null, cb, key); }); } }

  Read the article

• What's the different between an async delegate and async method?

  - by DayOne

  What's the different between an async delegate and async method? Someone told me they were different in C#, but I thought they were the same thing.

  Read the article

• Sync Vs. Async Sockets Performance in C#

  - by Michael Covelli

  Everything that I read about sockets in .NET says that the asynchronous pattern gives better performance (especially with the new SocketAsyncEventArgs which saves on the allocation). I think this makes sense if we're talking about a server with many client connections where its not possible to allocate one thread per connection. Then I can see the advantage of using the ThreadPool threads and getting async callbacks on them. But in my app, I'm the client and I just need to listen to one server sending market tick data over one tcp connection. Right now, I create a single thread, set the priority to Highest, and call Socket.Receive() with it. My thread blocks on this call and wakes up once new data arrives. If I were to switch this to an async pattern so that I get a callback when there's new data, I see two issues The threadpool threads will have default priority so it seems they will be strictly worse than my own thread which has Highest priority. I'll still have to send everything through a single thread at some point. Say that I get N callbacks at almost the same time on N different threadpool threads notifying me that there's new data. The N byte arrays that they deliver can't be processed on the threadpool threads because there's no guarantee that they represent N unique market data messages because TCP is stream based. I'll have to lock and put the bytes into an array anyway and signal some other thread that can process what's in the array. So I'm not sure what having N threadpool threads is buying me. Am I thinking about this wrong? Is there a reason to use the Async patter in my specific case of one client connected to one server?

  Read the article

• NHibernate.Search - async mode

  - by Atul

  Hi, I am using NHibernate Lucene search in my project. Lucene.Net.dll - v - 2.3.1.3 NHibernate.dll - v - 2.1.0.4000 At this point I am trying to use async option for indexing and used following options config.SetProperty(NHibernate.Search.Environment.WorkerExecution, "async"); config.SetProperty(NHibernate.Search.Environment.WorkerThreadPoolSize, "1"); config.SetProperty(NHibernate.Search.Environment.WorkerWorkQueueSize, "5000"); Questions 1) My initial index was not build with this option, when used these settings first time, I had error saying NHibernate.Search.dll not found. When I deleted existing index and then started working, it went fine. Do we need to rebuild indexes whenever we change config settings like above ? 2) How size of index should be interpreted; i.e. initially my index was about 400MB (build over the last few months), which I deleted. Later when I reindexed, the size of index went down to 5MB ! Search appear to be alright after limited testing, but such a change appeared bit scary. Should we delete/rebuild indexes once in a while & is it normal to change this drastically ? 3) Is my above setting is OK ? When I had WorkerThreadPoolSize=5, I once got Dr Watson kind of error. Please advise on best practices of using async configuration for search. Regards, Atul

  Read the article

• Silverlight HttpWebRequest.Create hangs inside async block

  - by jack2010

  I am trying to prototype a Rpc Call to a JBOSS webserver from Silverlight (4). I have written the code and it is working in a console application - so I know that Jboss is responding to the web request. Porting it to silverlight 4, is causing issues: let uri = new Uri(queryUrl) // this is the line that hangs let request : HttpWebRequest = downcast WebRequest.Create(uri) request.Method <- httpMethod; request.ContentType <- contentType It may be a sandbox issue, as my silverlight is being served off of my file system and the Uri is a reference to the localhost - though I am not even getting an exception. Thoughts? Thx UPDATE 1 I created a new project and ported my code over and now it is working; something must be unstable w/ regard to the F# Silverlight integration still. Still would appreciate thoughts on debugging the "hanging" web create in the old model... UPDATE 2 let uri = Uri("http://localhost./portal/main?isSecure=IbongAdarnaNiFranciscoBalagtas") // this WebRequest.Create works fine let req : HttpWebRequest = downcast WebRequest.Create(uri) let Login = async { let uri = new Uri("http://localhost/portal/main?isSecure=IbongAdarnaNiFranciscoBalagtas") // code hangs on this WebRequest.Create let request : HttpWebRequest = downcast WebRequest.Create(uri) return request } Login |> Async.RunSynchronously I must be missing something; the Async block works fine in the console app - is it not allowed in the Silverlight App?

  Read the article

• Sync Vs. Async Sockets Performance in .NET

  - by Michael Covelli

  Everything that I read about sockets in .NET says that the asynchronous pattern gives better performance (especially with the new SocketAsyncEventArgs which saves on the allocation). I think this makes sense if we're talking about a server with many client connections where its not possible to allocate one thread per connection. Then I can see the advantage of using the ThreadPool threads and getting async callbacks on them. But in my app, I'm the client and I just need to listen to one server sending market tick data over one tcp connection. Right now, I create a single thread, set the priority to Highest, and call Socket.Receive() with it. My thread blocks on this call and wakes up once new data arrives. If I were to switch this to an async pattern so that I get a callback when there's new data, I see two issues The threadpool threads will have default priority so it seems they will be strictly worse than my own thread which has Highest priority. I'll still have to send everything through a single thread at some point. Say that I get N callbacks at almost the same time on N different threadpool threads notifying me that there's new data. The N byte arrays that they deliver can't be processed on the threadpool threads because there's no guarantee that they represent N unique market data messages because TCP is stream based. I'll have to lock and put the bytes into an array anyway and signal some other thread that can process what's in the array. So I'm not sure what having N threadpool threads is buying me. Am I thinking about this wrong? Is there a reason to use the Async patter in my specific case of one client connected to one server?

  Read the article

• Some Async Socket Code - Help with Garbage Collection?

  - by divinci

  Hi all, I think this question is really about my understanding of Garbage collection and variable references. But I will go ahead and throw out some code for you to look at. // Please note do not use this code for async sockets, just to highlight my question // SocketTransport // This is a simple wrapper class that is used as the 'state' object // when performing Async Socket Reads/Writes public class SocketTransport { public Socket Socket; public byte[] Buffer; public SocketTransport(Socket socket, byte[] buffer) { this.Socket = socket; this.Buffer = buffer; } } // Entry point - creates a SocketTransport, then passes it as the state // object when Asyncly reading from the socket. public void ReadOne(Socket socket) { SocketTransport socketTransport_One = new SocketTransport(socket, new byte[10]); socketTransport_One.Socket.BeginRecieve ( socketTransport_One.Buffer, // Buffer to store data 0, // Buffer offset 10, // Read Length SocketFlags.None // SocketFlags new AsyncCallback(OnReadOne), // Callback when BeginRead completes socketTransport_One // 'state' object to pass to Callback. ); } public void OnReadOne(IAsyncResult ar) { SocketTransport socketTransport_One = ar.asyncState as SocketTransport; ProcessReadOneBuffer(socketTransport_One.Buffer); // Do processing // New Read // Create another! SocketTransport (what happens to first one?) SocketTransport socketTransport_Two = new SocketTransport(socket, new byte[10]); socketTransport_Two.Socket.BeginRecieve ( socketTransport_One.Buffer, 0, 10, SocketFlags.None new AsyncCallback(OnReadTwo), socketTransport_Two ); } public void OnReadTwo(IAsyncResult ar) { SocketTransport socketTransport_Two = ar.asyncState as SocketTransport; .............. So my question is: The first SocketTransport to be created (socketTransport_One) has a strong reference to a Socket object (lets call is ~SocketA~). Once the async read is completed, a new SocketTransport object is created (socketTransport_Two) also with a strong reference to ~SocketA~. Q1. Will socketTransport_One be collected by the garbage collector when method OnReadOne exits? Even though it still contains a strong reference to ~SocketA~ Thanks all!

  Read the article

• Silverlight Async Design Pattern Issue

  - by Mike Mengell

  I'm in the middle of a Silverlight application and I have a function which needs to call a webservice and using the result complete the rest of the function. My issue is that I would have normally done a synchronous web service call got the result and using that carried on with the function. As Silverlight doesn't support synchronous web service calls without additional custom classes to mimic it, I figure it would be best to go with the flow of async rather than fight it. So my question relates around whats the best design pattern for working with async calls in program flow. In the following example I want to use the myFunction TypeId parameter depending on the return value of the web service call. But I don't want to call the web service until this function is called. How can I alter my code design to allow for the async call? string _myPath; bool myFunction(Guid TypeId) { WS_WebService1.WS_WebService1SoapClient proxy = new WS_WebService1.WS_WebService1SoapClient(); proxy.GetPathByTypeIdCompleted += new System.EventHandler<WS_WebService1.GetPathByTypeIdCompleted>(proxy_GetPathByTypeIdCompleted); proxy.GetPathByTypeIdAsync(TypeId); // Get return value if (myPath == "\\Server1") { //Use the TypeId parameter in here } } void proxy_GetPathByTypeIdCompleted(object sender, WS_WebService1.GetPathByTypeIdCompletedEventArgs e) { string server = e.Result.Server; myPath = '\\' + server; } Thanks in advance, Mike

  Read the article

• Multiple instances of the same Async task (Windows Phone)

  - by Bart Teunissen

  After googeling for ages, and reading some stuff about async task in books. I made a my first program with an async task in it. Only to find out, that i can only start one task. I want to run the task more then once. This is where i found out that that doesn't seem to work. to be a little bit clearer, here are some parts of my code: InitFunction(var); This is the Task itself public async Task InitFunction(string var) { _VarHandle = await _AdsClient.GetSymhandleByNameAsync(var); _Data = await _AdsClient.ReadAsync<T>(_VarHandle); _AdsClient.AddNotificationAsync<T>(_VarHandle, AdsTransmissionMode.OnChange, 1000, this); } This works like a charm when i execute the task only once.. But is there a possibility to run it multiple times. Something like this? InitFunction(var1); InitFunction(var2); InitFunction(var3); Because if i do this now (multiple tasks at once), the task it wants to start is still running, and it throws an exeption. if someone could help me with this, that would be awesome! ~ Bart

  Read the article

• jQuery async ajax query and returning value problem (scope, closure)

  - by glebovgin

  Hi. Code not working because of async query and variable scope problem. I can't understand how to solve this. Change to $.ajax method with async:false - not an option. I know about closures, but how I can implement it here - don't know. I've seen all topics here about closures in js and jQuery async problems - but still nothing. Help, please. Here is the code: var map = null; var marker; var cluster = null; function refreshMap() { var markers = []; var markerImage = new google.maps.MarkerImage('/images/image-1_32_t.png', new google.maps.Size(32, 32)); $.get('/get_users.php',{},function(data){ if(data.status == 'error') return false; var users = data.users; // here users.length = 1 - this is ok; for(var i in users) { //here I have every values from users - ok var latLng = new google.maps.LatLng(users[i].lat, users[i].lng); var mark = new google.maps.Marker({ position: latLng, icon: markerImage }); markers.push(mark); alert(markers.length); // length 1 } },'json'); alert(markers.length); // length 0 //if I have alert() above - I get result cluster = new MarkerClusterer(map, markers, { maxZoom: null, gridSize: null }); } Thanks.

  Read the article

• async tree jquery easy ui

  - by user765368

  I'm trying to create an Async Tree in jQuery Easy Ui. I understand the idea behind it, but will this work if my root node is not a node that is coming from the database or something (therefore, it does not have any id). My root node is some node that I define myself. How would I make an async tree in jquery easy ui to load a bunch of nodes as children of my root node (which, again has no id because it's not coming from the database. My children nodes are coming from the database though). I hope y'all understand what I'm trying to do here. Any help please

  Read the article

• Async friendly DispatcherTimer wrapper/subclass

  - by Simon_Weaver

  I have a DispatcherTimer running in my code that fire every 30 seconds to update system status from the server. The timer fires in the client even if I'm debugging my server code so if I've been debugging for 5 minutes I may end up with a dozen timeouts in the client. Finally decided I needed to fix this so looking to make a more async / await friendly DispatcherTimer. Code running in DispatcherTimer must be configurable whether it is reentrant or not (i.e. if the task is already running it should not try to run it again) Should be task based (whether or not this requires I actually expose Task at the root is a gray area) Should be able to run async code and await on tasks to complete Whether it wraps or extends DispatcherTimer probably doesn't really matter but wrapping it may be slightly less ambiguous if you don't know how to use it Possibly expose bindable properties for IsRunning for UI

  Read the article

• Boost asio async vs blocking reads, udp speed/quality

  - by Dolphin

  I have a quick and dirty proof of concept app that I wrote in C# that reads high data rate multicast UDP packets from the network. For various reasons the full implementation will be written in C++ and I am considering using boost asio. The C# version used a thread to receive the data using blocking reads. I had some problems with dropped packets if the computer was heavily loaded (generally with processing those packets in another thread). What I would like to know is if the async read operations in boost (which use overlapped io in windows) will help ensure that I receive the packets and/or reduce the cpu time needed to receive the packets. The single thread doing blocking reads is pretty straightforward, using the async reads seems like a step up in complexity, but I think it would be worth it if it provided higher performance or dropped fewer packets on a heavily loaded system. Currently the data rate should be no higher than 60Mb/s.

  Read the article

< Previous Page | 1 2 3 4 5 6 7 8 9 10 11 12  | Next Page >