uagent¶ ↑

Helps you to develop web applications for desktop or mobile user agents.

$ gem install uagent

When a browser sends a request to your web application the request has an HTTP_USER_AGENT attribute that identifies the device an browser. For example, the next string identifies an particular model of iPhone, that uses an specific mobile version for Safari.

Mozilla/5.0 (iPhone; U; CPU iPhone OS 3_1_2 like Mac OS X; en-us) 
AppleWebKit/528.18 (KHTML, like Gecko) Version/4.0 Mobile/7D11
Safari/528.16

Each mobile phone model will send you a particular user agent string, thus is a good idea classify the devices in groups an develop a specific interface for each group. For each group we define a key, so the user agent parser receive the user agent string and returns that key. For example, the answer for the string above could be :mobile or :iphone, depending on the parser configuration.

If you are developing web applications on top of rack, I recommend you to look the uagent_rack gem.

require 'rubygmes'
require 'uagent'

# A parser distinguishes between disjoin user agent sets

parser = UAgent::Parser.new

env = {
  ...
  "HTTP_USER_AGENT" => "Mozilla/5.0 (iPhone; U; CPU iPhone OS 3_1_2 like Mac OS X; en-us) " +
      "AppleWebKit/528.18 (KHTML, like Gecko) Version/4.0 Mobile/7D11 Safari/528.16",
  ...
}

parser.call(env)    # gets :mobile

env = {
  ...
  "HTTP_USER_AGENT" => "Mozilla/5.0 (X11; U; Linux i686; en-US; rv:1.9.2.10) " +
      "Gecko/20100915 Ubuntu/10.04 (lucid) Firefox/3.6.10"
  ...
}

parser.call({ 'HTTP_USER_AGENT' => 'ua })    # gets :desktop

The basic user agent groups are :desktop and :mobile. You can add more groups adding keys in the constructor function.

parser = UAgent::Parser.new(:iphone)

ua = "Mozilla/5.0 (iPhone; U; CPU iPhone OS 3_1_2 like Mac OS X; en-us) " +
     "AppleWebKit/528.18 (KHTML, like Gecko) Version/4.0 Mobile/7D11 Safari/528.16"

parser.call({ 'HTTP_USER_AGENT' => 'ua })    # gets :iphone

The keys order in the constructor is relevant. Put the most specific keys first to indicate the parser to start for them.

The parser uses a hash that associates terms to the user agent group keyword. That terms are searched in the HTTP_USER_AGENT string to analyze if a user agent is into a group. Now we support only the keywords :iphone and :blackberry, thus change the database if you need a more accurate parser.

parser.set_database my_custom_database

First download the code from the repository:

$ git clone git://github.com/danielhz/uagent.git

This project uses jeweler to build the gem, so you can use this commands:

$ rake build            # to build the gem
$ rake install          # to build and install the gem in one step

Also, if you want test the gem you can use the spec task:

$ rake spec

This project uses rcov so you can check the coverage opening the HTML file in the coverage directory after running the spec.

Author

Daniel Hernández, daniel@degu.cl

License

GPL V3

This software is provided “as is” and without any express or implied warranties, including, without limitation, the implied warranties of merchantability and fitness for a particular purpose.