Setting up a websocket on Apache

Question

So I m doing some research on websockets  and I have a few questions I can t seem to find a definitive answer for    How can I set up a web socket on my Linux server  Is there an Apache module  Would I have to use 3rd-party PHP code or similar  Are there any kinds of drawbacks to the method described in question 1 that I should be aware of other than browser compatibility  How could I  upgrade  my websocket installation to a secure websocket installation  ws    to wss      Would this be made easier or more difficult if SSL was already set up on my Apache server  Is there any language I could use to connect to my web socket other than JavaScript  What is the default request method for a web socket

User · Answer

I struggled to understand the proxy settings for websockets for https therefore let me put clarity here what i realized.

First you need to enable proxy and proxy_wstunnel apache modules and the apache configuration file will look like this.

<IfModule mod_ssl.c>
    <VirtualHost _default_:443>
      ServerName www.example.com
        ServerAdmin webmaster@localhost
        DocumentRoot /var/www/your_project_public_folder

      SSLEngine on
      SSLCertificateFile    /etc/ssl/certs/path_to_your_ssl_certificate
      SSLCertificateKeyFile /etc/ssl/private/path_to_your_ssl_key

      <Directory /var/www/your_project_public_folder>
              Options Indexes FollowSymLinks
              AllowOverride All
              Require all granted
              php_flag display_errors On
      </Directory>
      ProxyRequests Off 
      ProxyPass /wss/  ws://example.com:port_no

        ErrorLog ${APACHE_LOG_DIR}/error.log
        CustomLog ${APACHE_LOG_DIR}/access.log combined
    </VirtualHost>
</IfModule>

in your frontend application use the url "wss://example.com/wss/" this is very important mostly if you are stuck with websockets you might be making mistake in the front end url. You probably putting url wrongly like below.

wss://example.com:8080/wss/ -> port no should not be mentioned
ws://example.com/wss/ -> url should start with wss only.
wss://example.com/wss -> url should end with / -> most important

also interesting part is the last /wss/ is same as proxypass value if you writing proxypass /ws/ then in the front end you should write /ws/ in the end of url.

User · Answer

I can t answer all questions  but I will do my best   As you already know  WS is only a persistent full-duplex TCP connection with framed messages where the initial handshaking is HTTP-like  You need some server that s listening for incoming WS requests and that binds a handler to them   Now it might be possible with Apache HTTP Server  and I ve seen some examples  but there s no official support and it gets complicated  What would Apache do  Where would be your handler  There s a module that forwards incoming WS requests to an external shared library  but this is not necessary with the other great tools to work with WS   WS server trends now include  Autobahn  Python  and Socket IO  Node js   JavaScript on the server   The latter also supports other hackish  persistent  connections like long polling and all the COMET stuff  There are other little known WS server frameworks like Ratchet  PHP  if you re only familiar with that    In any case  you will need to listen on a port  and of course that port cannot be the same as the Apache HTTP Server already running on your machine  default   80   You could use something like 8080  but even if this particular one is a popular choice  some firewalls might still block it since it s not supposed to be Web traffic  This is why many people choose 443  which is the HTTP Secure port that  for obvious reasons  firewalls do not block  If you re not using SSL  you can use 80 for HTTP and 443 for WS  The WS server doesn t need to be secure  we re just using the port   Edit  According to Iharob Al Asimi  the previous paragraph is wrong  I have no time to investigate this  so please see his work for more details   About the protocol  as Wikipedia shows  it looks like this   Client sends   GET  mychat HTTP 1 1 Host  server example com Upgrade  websocket Connection  Upgrade Sec-WebSocket-Key  x3JJHMbDL1EzLkh9GBhXDw   Sec-WebSocket-Protocol  chat Sec-WebSocket-Version  13 Origin  http   example com   Server replies   HTTP 1 1 101 Switching Protocols Upgrade  websocket Connection  Upgrade Sec-WebSocket-Accept  HSmrc0sMlYUkAGmm5OPpG2HaGWk  Sec-WebSocket-Protocol  chat   and keeps the connection alive  If you can implement this handshaking and the basic message framing  encapsulating each message with a small header describing it   then you can use any client-side language you want  JavaScript is only used in Web browsers because it s built-in   As you can see  the default  request method  is an initial HTTP GET  although this is not really HTTP and looses everything in common with HTTP after this handshaking  I guess servers that do not support  Upgrade  websocket Connection  Upgrade   will reply with an error or with a page content

User · Answer

The new version 2 4 of Apache HTTP Server has a module called mod proxy wstunnel which is a websocket proxy   http   httpd apache org docs 2 4 mod mod proxy wstunnel html

[apache] Setting up a websocket on Apache?

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