^{HTTPserver 2.1}

The HTTPSERVER module is a simple HTTP server used to share HTML documents on the World Wide Web ; it allows to access directly from a browser or from a link inside a Scol site using the IN/OUT module (either using fix IP adresses or obtaining them through the HTTP_SERVER which is very useful when changing IP for example).

A basic CGI application will soon be available via DMS queries. The server's configuration requires the following :

- A TCP port : 80 (by default) or 8080 (WWW server), however, it may be the case that either the server cannot be started, or users cannot connect :
ports lower than 1023 are often blocked by firewalls and/or the systems.
- A root directory for HTML documents : the server is referenced as ‘http://x.x.x.x’, where x.x.x.x represents the IP (the name of the machine can be used
if it is registered in the DNS directory) and each URL will be annexed in the document's root directory.
For example:‘http://x.x.x.x/my_documents/mondoc.html’ represents the file [root_directory]\my_documents\mondoc.html in the SCOL partition.

To process HTTP errors, the server can provide specific HTML pages referenced in the root directory in ‘/error/codexxx.html’. The most common HTTP error codes are :
* 400 Bad query
* 404 Page not found
* 501 Not implemented

The HTTPSERVER module includes a special filter used to create a valid URL from a simple HTTP path ; an action (url_in) and an event (url_out) are available. For example :
A client want to access to the "site/news.html" page but it does not know either the server IP nor its port number.
By linking a event to the url_in action with the HTTP path as parameter (for example "site/news.html"), the event will be triggered avec the full URL as parameter (for example "http://x.x.x.x[:port]/site/news.html"). Thus this event will be link to the openURL action of the InOut module.
Attention : the port number is added to the URL only if different from 80.

Figure 1 : HTTPserver module Interface

(1) : Port => Used to specify the port (80 by default).

(2) : Root => Used to declare the HTTP root directory (sub-folder of the scol partition

• Open the SCS creation tree. Select the Db file then double-click on HTTPSERVER 2.1.
  
• Create required links for the project.