httpd Module

Ovidiu Sas

   <osas@voipembedded.com>

Edited by

Ovidiu Sas

   Copyright © 2012-2013 VoIP Embedded, Inc.
   Revision History
   Revision $Rev: 8580 $ $Date$
     __________________________________________________________

   Table of Contents

   1. Admin Guide

        1.1. Overview
        1.2. Dependencies

              1.2.1. OpenSIPS Modules
              1.2.2. External Libraries or Applications

        1.3. Exported Parameters

              1.3.1. ip(string)
              1.3.2. port(integer)
              1.3.3. buf_size (integer)
              1.3.4. post_buf_size (integer)

        1.4. Exported MI Functions

              1.4.1. httpd_list_root_path

        1.5. Exported Functions
        1.6. Known issues

   2. Developer Guide

        2.1. Available Functions

              2.1.1. register_httpdcb (module, root_path,
                      httpd_acces_handler_cb, httpd_flush_data_cb,
                      httpd_init_proc_cb)

   List of Examples

   1.1. Set ip parameter
   1.2. Set port parameter
   1.3. Set buf_size parameter
   1.4. Set post_buf_size parameter

Chapter 1. Admin Guide

1.1. Overview

   This module provides an HTTP transport layer for OpenSIPS.

   Implementation of httpd module's http server is based on
   libmicrohttpd library.

1.2. Dependencies

1.2.1. OpenSIPS Modules

   The following modules must be loaded before this module:
     * No dependencies on other OpenSIPS modules.

1.2.2. External Libraries or Applications

   The following libraries or applications must be installed
   before running OpenSIPS with this module loaded:
     * libmicrohttpd.

1.3. Exported Parameters

1.3.1. ip(string)

   The IP address used by the HTTP server to listen for incoming
   requests.

   The default value is an empty string. If no IP address is set,
   then the http server will bind to all available IPs.

   Example 1.1. Set ip parameter
...
modparam("httpd", "ip", "127.0.0.1")
...

1.3.2. port(integer)

   The port number used by the HTTP server to listen for incoming
   requests.

   The default value is 8888. Ports lower than 1024 are not
   accepted.

   Example 1.2. Set port parameter
...
modparam("httpd", "port", 8000)
...

1.3.3. buf_size (integer)

   It specifies the maximum length (in bytes) of the buffer used
   to write in the html response.

   If the size of the buffer is set to zero, it will be
   automatically set to a quarter of the size of the pkg memory.

   The default value is 0.

   Example 1.3. Set buf_size parameter
...
modparam("httpd", "buf_size", 524288)
...

1.3.4. post_buf_size (integer)

   It specifies the length (in bytes) of the POST HTTP requests
   processing buffer. For large POST request, the default value
   might require to be increased.

   The default value is 1024. The minumal value is 256.

   Example 1.4. Set post_buf_size parameter
...
modparam("httpd", "post_buf_size", 4096)
...

1.4. Exported MI Functions

1.4.1. httpd_list_root_path

   Lists all the registered http root paths into the httpd module.
   When a request comes in, if the root parth is in the list, the
   request will be sent to the module that register it.

   Name: httpd_list_root_path

   Parameters: none

   MI FIFO Command Format:
:httpd_list_root_path:_reply_fifo_file_
_empty_line_

1.5. Exported Functions

   No function exported to be used from configuration file.

1.6. Known issues

   Due to the fact that OpenSIPS is a multiprocess application,
   the microhttpd library is used in "external select" mode. This
   ensures that the library is not running in multithread mode and
   the library is entirely controled by OpenSIPS. Due to this
   particular mode of operations, for now, the entire http
   response is built in a pre-allocated buffer (see buf_size
   parameter).

   Future realeases of this module will address this issue.

   Running the http daemon as non root on ports below 1024 is
   forbidden by default in linux (kernel>=2.6.24). To allow the
   port binding, one can use setcap to give extra privilleges to
   opensips binary:
setcap 'cap_net_bind_service=+ep' /usr/local/sbin/opensips

Chapter 2. Developer Guide

2.1. Available Functions

2.1.1.  register_httpdcb (module, root_path, httpd_acces_handler_cb,
httpd_flush_data_cb, httpd_init_proc_cb)

   Register a new http root with it's associated callbacks into
   the httpd module.

   Meaning of the parameters is as follows:
     * const char *mod - name of the module that register an http
       root path to be handled;
     * str *root_path - the registered root path;
     * httpd_acces_handler_cb f1 - handler to the callback method
       to be called on root path match;
     * httpd_flush_data_cb f2 - handler to the callback method to
       be called for sending extra data (at a later time);
     * httpd_init_proc_cb f3 - handler to the callback method to
       be called during httpd process init;
