Nginx for long-connected applications

Whether you do the Web backend or app backend, or SOA service, long connection is a good choice, on the one hand to save the resource consumption of establishing a connection each time, on the other hand, can make the message timely response, improve the experience.

Here is a way to implement a long connection via Nginx module, which is a long connection on the HTTP protocol, strictly speaking the HTTP protocol itself is request-response, and there is no strict meaning of long connection, so-called long-term connection is when there is no corresponding time, can hold, Until there is a corresponding, then reestablish the connection immediately.

Here's how to implement it.

1, first download nginx_http_push_module and Nginx, on these two tar files;

2. Copy the two tar files to the Linux system and execute them under the Nginx directory:

  ./configure--add-module=path/to/nginx_http_push_module ... makemake install

3, the middle may appear can not find the Pcre module, etc., if you are a CentOS system, use yum-y install Pcre-devel OpenSSL openssl-devel installed
After installation, continue to perform Nginx installation

4, such as Nginx are installed after the configuration of long connection:

nginx.conf file in/use/local/nginx/conf
Add to:

  location/publish {     set $push _channel_id $arg _id;     Push_publisher;     Push_store_messages on;     Push_message_timeout 2h;     Push_max_message_buffer_length 10; } location/activity {     push_subscriber;     Set $push _channel_id $arg _id;     Push_subscriber_concurrency broadcast;     Default_type Text/plain; }

5, restart Ngnix, Access http://Your IP port/activity?id= your channel, if the browser has been waiting,
Then, you write a piece of code to publish a message, if the browser can accept that the installation is successful!

    public void Testnginx () {        String http = "Http://172.16.4.108/publish?id=my";        Postmethod Postmethod = new Postmethod (HTTP);        Requestentity requestentity = new Stringrequestentity ("444");        Postmethod.setrequestentity (requestentity);        try{            int status =this.client.executemethod (Postmethod);            if (status = = Httpstatus.sc_ok) {                String text = postmethod.getresponsebodyasstring ();                System.out.println (text);            }        } catch (Exception e) {            e.printstacktrace ();        }    }

6, the above are installed after the start of our own logic

Here is the listener, here is a simple implementation, we need to always record a lastmodified on the listener, this time represents the last time he received a new message

private static String ETag = "";    private static String lastmodified = "";            public static void Main (string[] args) {while (true) {HttpClient HttpClient = new HttpClient ();            String http = "Http://172.16.4.108/activity?id=my";            GetMethod GetMethod = new GetMethod (HTTP);            Getmethod.setrequestheader ("Connection", "keep-alive");            Getmethod.setrequestheader ("If-none-match", ETag);            Getmethod.setrequestheader ("If-modified-since", lastmodified);                try {int status = Httpclient.executemethod (GetMethod); if (Getmethod.getresponseheader ("etag") = null) {ETag = Getmethod.getresponseheader ("ETag"). GetValue ()                ; } if (Getmethod.getresponseheader ("last-modified")! = null) {lastmodified = getmethod.ge                Tresponseheader ("Last-modified"). GetValue (); } System.out.println ("etag=" + ETag + "; lastmodif=" + LastModified + "; status=" + status);                    if (status = = HTTPSTATUS.SC_OK) {String text = getmethod.getresponsebodyasstring ();                System.out.println (text);            }} catch (Exception e) {e.printstacktrace (); }        }    }

Here is the Send message end: The same code we used when we tested it.

        public void Testnginx () {        String http = "Http://172.16.4.108/publish?id=my";        Postmethod Postmethod = new Postmethod (HTTP);        Requestentity requestentity = new Stringrequestentity ("444");        Postmethod.setrequestentity (requestentity);        try{            int status =this.client.executemethod (Postmethod);            if (status = = Httpstatus.sc_ok) {                String text = postmethod.getresponsebodyasstring ();                System.out.println (text);            }        } catch (Exception e) {            e.printstacktrace ();        }    }

Here, our plan is finished.

Nginx for long-connected applications