ejabberd-contrib/mod_ecaptcha

mod_ecaptcha - Generate CAPTCHAs using ecaptcha

Requires:

• ejabberd 23.xx or higher
• C compiler and makefile
• write access to ejabberd's priv dir

This small module uses the ecaptcha erlang library to generate CAPTCHA images suitable for ejabberd's CAPTCHA feature.

Basic Configuration

The minimal configuration required to get this module working is:

captcha_cmd: mod_ecaptcha

captcha_url: http://localhost:5280/captcha

listen:
  -
    port: 5280
    module: ejabberd_http
    request_handlers:
      /captcha: ejabberd_captcha

modules:
  mod_ecaptcha: {}

Options

The configurable options match mostly the ones from ecaptcha library:

• numchars

  Number of characters to include in the CAPTCHA image. Default: 5

• effects

  List of effects to use to generate the CAPTCHA image. Check ecaptcha usage for details. Default: [line, blur, filter, dots, reverse_dots]

• color

  This option defines the image's color. Valid values: black, red, orange, blue, pink or purple. Default: black

• alphabet

  String containing all the characters that can be printed on the image (duplicates are ok). The default value includes: numbers, latin characters lower and upper case.

• font

  String of one of the supported fonts. Please notice that fonts are pre-rendered at NIF compile-time, see the deps/ecaptcha/c_src/fonts.h and FONTS parameter in deps/ecaptcha/c_src/Makefile. Default: hplhs-oldstyle

Example Configuration

This example configuration setups CAPTCHA images that are simple to solve: just 3 characters, only the vocals in lower and upper case.

It also setups mod_register_web, you can test the feature immediately visiting http://localhost:5280/register/

captcha_cmd: mod_ecaptcha

captcha_url: http://localhost:5280/captcha

listen:
  -
    port: 5280
    module: ejabberd_http
    request_handlers:
      /captcha: ejabberd_captcha
      /register: mod_register_web

modules:
  mod_ecaptcha:
    numchars: 3
    effects: [line, dots]
    color: red
    alphabet: "aeiouAEIOU"
    font: "hplhs-oldstyle"