NAME

WebService::GData::ClientLogin - implements ClientLogin authorization for google data related APIs v2.

SYNOPSIS

#you will want to use a service instead such as WebService::GData::YouTube;
use WebService::GData::Base;
use WebService::GData::ClientLogin;

#create an object that only has read access
my $base = new WebService::GData::Base();

my $auth;

eval {
    $auth = new WebService::GData::ClientLogin(
        email    => '...',
        password => '...',
        service  => '...', #default to youtube,
        source   => '...' #default to WebService::GData::ClientLogin-$VERSION,
        type    => '...'  #default to HOSTED_OR_GOOGLE
    );
};
if(my $error = $@){
    #$error->code,$error->content...
}

if($auth->captcha_url){
    #display the image and get the answer from the user
    #then try to login again
}

#everything is fine...
#give write access to the above user...

$base->auth($auth);

#now you can... (url are here for examples!)

#create a new entry with application/x-www-form-urlencoded content-type

my $ret = $base->post('http://gdata.youtube.com/feeds/api/users/default/playlists',$content);

#if it fails a first time, you will need to add captcha related parameters:
my $auth;
eval {
    $auth = new WebService::GData::ClientLogin(
        email          => '...',
        password       => '...',
        captcha_token  => '...',
        captcha_answer => '...'
    );
};
    
#youtube specific developer key 
my $auth;
eval {	
    $auth = new WebService::GData::ClientLogin(
         email    => '...',
         password => '...',
          key      => '...',
    );
};

DESCRIPTION

inherits from WebService::GData

Google services supports different authorization systems allowing you to write data programmaticly. ClientLogin is one of such system. This package tries to get an authorization key to the service specified by logging in with the user account information: email and password. If the loggin succeeds, the authorization key generated grants you access to write actions as long as you pass the key with each requests.

ClientLogin authorization key does expire but the expire time is set on a per service basis. You should use this authorization system for installed applications. Web application should use the OAuth (to be implemented) or AuthSub (will be deprecated and will not be implemented) authorization systems.

The connection is done via ssl, therefore you should install Crypt::SSLeay before using this module or an error code: 'missing_ssl_module' will be thrown.

More information about ClientLogin can be found here:

http://code.google.com/intl/en/apis/accounts/docs/AuthForInstalledApps.html

Some problems can be encountered if your account is not directly linked to a Google Account.

Please see http://apiblog.youtube.com/2011/03/clientlogin-fail.html.

CONSTRUCTOR

new

Create an instance by passing an hash.

Parameters

settings:Hash an hash containing the following keys:(* parameters are optional)

email

Specify the user email account.

password

Specifies the user password account.

service (default to youtube)

Specify the service you want to log in. youtube for youtube, cl for calendar,etc.

List available here:http://code.google.com/intl/en/apis/base/faq_gdata.html#clientlogin.

Constants available in WebService::GData::Constants

source (default to WebService::GData::ClientLogin-$VERSION)

Specify the name of your application in the following format "company_name-application_name-version_id". You should provide a real source to avoid getting blocked because Google thought you are a bot...

type* (default to HOSTED_OR_GOOGLE)

Specify the type of account: GOOGLE,HOSTED or HOSTED_OR_GOOGLE.

key*

The key must be specified for YouTube service. See key() for further information about the key.

captcha_token*

Specify the captcha_token you received in response to a failure to log in.

captcha_answer*

Specify the answer of the user for the CAPTCHA.

Returns

WebService::GData::ClientLogin

Throws

WebService::GData::Error

If the email or password is not set it will throw an error with invalid_parameters code. Other errors might happen while trying to connect to the service. You should look at the error code and content.

See also http://code.google.com/intl/en/apis/accounts/docs/AuthForInstalledApps.html#Errors for error code list.

You can use WebService::GData::Constants to check the error code.

Example:

use WebService::GData::Base;
use WebService::GData::ClientLogin;	

my $auth = new WebService::GData::ClientLogin(
    email          => '...',
    password       => '...',
    captcha_token  => '...',
    captcha_answer => '...'
);

my $base = new WebService::GData::YouTube(auth=>$auth);

CONSTRUCTOR GETTER METHODS

All these methods allows you to get access to the data you passed to the constructor or to the data you got back from the server.

email

Get the email address set to log in.

Parameters

none

Returns

email:Scalar

Example:

    use WebService::GData::ClientLogin;	
    
    my $auth = new WebService::GData::ClientLogin(
        email          => '...',
        password       => '...'
    );
    
    $auth->email;

	   

password

Get the password set to log in.

Parameters

none

Returns

password:Scalar

Example:

    use WebService::GData::ClientLogin;	
    
    my $auth = new WebService::GData::ClientLogin(
        email          => '...',
        password       => '...'
    );
    
    $auth->password;

	   

source

Get the source set to log in.

Parameters

none

Returns

source:Scalar

Example:

 use WebService::GData::ClientLogin;	
 
 my $auth = new WebService::GData::ClientLogin(
     email          => '...',
     password       => '...'
 );
 
 $auth->source;#by default WebService::GData::ClientLogin-$VERSION

service

Get the service set to log in.

Parameters

none

Returns

service:Scalar

Example:

 use WebService::GData::ClientLogin;	
 
 my $auth = new WebService::GData::ClientLogin(
     email          => '...',
     password       => '...'
 );
 
 $auth->service;#by default youtube

type

Get the account type set to log in.

Parameters

none

Returns

account_type:Scalar

Example:

 use WebService::GData::ClientLogin;	
 
 my $auth = new WebService::GData::ClientLogin(
     email          => '...',
     password       => '...'
 );
 
 $auth->service;#by default HOSTED_OR_GOOGLE

key

The key is required by the youtube service to identify the application making the request. You must handle this in the developer dashboard:http://code.google.com/apis/youtube/dashboard/.

See also http://code.google.com/intl/en/apis/youtube/2.0/developers_guide_protocol.html#Developer_Key.

Parameters

none

Returns

key:Scalar

Example:

 use WebService::GData::ClientLogin;	
 
 my $auth = new WebService::GData::ClientLogin(
     email          => '...',
     password       => '...',
     key            => '...'
 );
 
 $auth->key;

CAPTCHA GETTER METHODS

The following getters are used in case of failure to connect leading in an error response from the service requiring to proove that you are a human (or at least seem to...). The reason for this error to arrive could be several errors to log in in a short interval of time.

captcha_token

Get the captcha token sent back by the server after a failure to connect leading to a CaptchaRequired error message.

Parameters

none

Returns

captcha_token:Scalar

Example:

 use WebService::GData::ClientLogin;	
 
 my $auth = new WebService::GData::ClientLogin(
     email          => '...',
     password       => '...'
 );
 
 $auth->captcha_token;#by default nothing, so if you have something, you did not succeed in logging in.

captcha_url

Get the captcha token sent back by the server after a failure to connect leading to a CaptchaRequired error message. This url links to an image containing the challenge.

Parameters

none

Returns

captcha_url:Scalar

Example:

 use WebService::GData::ClientLogin;	
 
 my $auth = new WebService::GData::ClientLogin(
     email          => '...',
     password       => '...',
 );
 
 my $url = $auth->captcha_url;#by default nothing, so if you have something, you did not succeed in logging in.
 
 #you could do:
 
 print qq[<img src="$url"/>]; #display a  message to decrypt...

captcha_answer

Get the answer from the user after he/she was presented with the captcha image (link in captcha_url). You set this parameter in the constructor.

Parameters

none

Returns

captcha_answer:Scalar

Example:

 use WebService::GData::ClientLogin;	
 
 my $auth = new WebService::GData::ClientLogin(
     email          => '...',
     password       => '...'
 );
 
 my $url = $auth->captcha_url;#by default nothing, so if you have something, you did not succeed in logging in.
 
 #you could do:
 
 print qq[<img src="$url"/>]; #display a  message to decrypt...
 print q[<input type="text" name="captcha_answer" value=""/>];#let the user enters the message displayed

authorization_key

Get the authorization key sent back by the server in case of success to log in. This will be the key you put in the Authorization header to each protect content that you want to request. This is handled by each service and should be transparent to the end user of the library.

Parameters

none

Returns

authorization_key:Scalar

Example:

 use WebService::GData::ClientLogin;	
 
 my $auth = new WebService::GData::ClientLogin(
     email          => '...',
     password       => '...'
 );
 
 my $url = $auth->authorization_key;#by default nothing, so if you have something, you did succeed in logging in.
 

HANDLING ERROR/CAPTCHA

Google data APIs relies on querying remote urls on particular services. All queries that fail will throw (die) a WebService::GData::Error object. The error instance will contain the error code as a string in code() and the full error string in content().

The CaptchaRequired code return by the service does not throw an error though as you can recover by a captcha.

Below is an example of how to implement the logic for a captcha in a web context.

(WARNING:shall not be used in a web context though but easy to grasp!)

Example:

    use WebService::GData::Constants qw(:errors);
    use WebService::GData::ClientLogin;

    my $auth;	
    eval {
        $auth   = new WebService::GData::ClientLogin(
            email => '...',#from the user
            password =>'...',#from the user
            service =>'youtube',
            source =>'MyCompany-MyApp-2'
        );
    };

    if(my $error = $@) {
        #something went wrong, display some info to the user
        #$error->code,$error->content
        if($error->code eq BAD_AUTHENTICATION){
            #display a message to the user...
        }
    }

    #else it seems ok but...

    #check to see if got back a captcha_url

    if($auth->captcha_url){
        
        #ok, so there was something wrong, we'll try again.
        
        my $img = $auth->captcha_url;
        my $key = $auth->captcha_token;
		
        #here an html form as an example
        #(WARNING:shall not be used in a web context but easy to grasp!)
        
        print q[<form action="/cgi-bin/...mycaptcha.cgi" method="POST">];
        print qq[<input type="hidden" value="$key" name="captcha_token"/>];
        print qq[<input type="text" value="" name="email"/>];
        print qq[<input type="text" value="" name="password"/>];
        print qq[<img src="$img" />];
        print qq[<input type="text" value=""  name="captcha_answer"/>];
        
        #submit button here
    }
    
    #once the form is submitted, in your mycaptcha.cgi program:
    
    my $auth;	
    eval {
        $auth   = new WebService::GData::ClientLogin(
            email => '...',#from the user
            password =>'...',#from the user
            service =>'youtube',
            source =>'MyCompany-MyApp-2',
            captcha_token => '...',#from the above form
            captcha_answer => '...'#from the user
        );
    };

    ##error checking again:lather,rinse,repeat...

DEPENDENCIES

LWP

Crypt::SSLeay

BUGS AND LIMITATIONS

If you do me the favor to _use_ this module and find a bug, please email me i will try to do my best to fix it (patches welcome)!

AUTHOR

shiriru <shirirulestheworld[arobas]gmail.com>

LICENSE AND COPYRIGHT

This library is free software; you can redistribute it and/or modify it under the same terms as Perl itself.

cpanm WebService::GData

perl -MCPAN -e shell
install WebService::GData