++ed by:
גאבור סבו - Gábor Szabó

NAME

WebService::GData::Query - implements the core query parameters available in the google data API v2.

SYNOPSIS

    use WebService::GData::Query;
    use WebService::GData::Constants qw(:format :query :general);

    my $query = new WebService::GData::Query();

    $query->to_query_string();# by default:?alt=json&v=2&prettyprint=false&strict=true

    #?alt=jsonc&v=2&prettyprint=false&strict=true&start-index=1&max-results=10
    $query->alt('jsonc')->limit(10,1)->to_query_string();

    print $query->get('alt');#jsonc

    $query->v(1);#throw an error as only 2 is ok.
    $query->prettyprint(1);#throw an error as only 'true' or 'false' is possible.

    #use constants where you can 

    $query->prettyprint(TRUE);

    $query->alt('json-c');#this is wrong

    $query->alt(JSONC);#ok!

DESCRIPTION

inherits from WebService::GData.

Google data API supports searching different services via a common set of parameters. Unfortunately, some services only handles a subset of this "core" parameters... You should read the service Query documentation to know exactly the available parameters. This package also implements some helpers functions to shorten up a little the parameter settings.

In order to avoid to send uncorrect parameter values, the package checks for their validity and will throw a WebService::GData::Error object containing 'invalid_parameter_type' as the code and the name of the function as the content. Checking the data before sending a request will avoid unnecessary network transactions and reduce the risk of reaching quota limitations in use for the service you are querying.

WebService::GData::Constants contains predefined value that you can use to set the parameters. Using the constants can avoid typo errors or unnecessary code change when an update is available with a new value.

CONSTRUCTOR

new

    Creates a basic query instance. The following parameters are set by default:

    alt = WebService::GData::Constants::JSON
    v = WebService::GData::Constants::GDATA_MINIMUM_VERSION
    prettyprint = WebService::GData::Constants::FALSE
    strict = WebService::GData::Constants::TRUE

    Parameters

    none

    Returns

    WebService::GData::Query

    Example:

        use WebService::GData::Query;
    
        my $query = new WebService::GData::Query();
    
        $query->to_query_string();# by default:?alt=json&v=2&prettyprint=false&strict=true

GENERAL METHODS

get

    Returns the parameter specified.

    The function uses the underscore nomenclature where the parameters use the hyphen nomenclature. You should change all the underscore to hyphen when accessing the value.

    Parameters

    parameter_name:Scalar

    Return

    parameter_value::Scalar

    Example:

        use WebService::GData::Query;
    
        my $query = new WebService::GData::Query();
    
        $query->get('alt');#json
    
        $query->get('published_min');#does not work...
    
        $query->get('published-min');#ok!

to_query_string

    Concatene each parameter/value pair into a query string. This function is also called in a string overload context. "$instance" is the same as $instance->to_query_string();

    Parameters

    none

    Returns

    query_string:Scalar

    Example:

        use WebService::GData::Query;
    
        my $query = new WebService::GData::Query();
    
        $query->to_query_string();#?alt=json&v=2&prettyprint=false&strict=true
        "$query";                 #?alt=json&v=2&prettyprint=false&strict=true
        print $query;             #?alt=json&v=2&prettyprint=false&strict=true

PARAMETER METHODS

All the methods that set a parameter return the instance so that you can chain the function calls.

Example:

    $query->alt(JSONC)->limit(10,1)->strict(TRUE)->prettyprint(FALSE)->to_query_string();

The following setters are available:

strict

    If set to true (default), setting a parameter not supported by a service will fail the request.

    Parameters

    true_or_false:Scalar - The value can be WebService::Gdata::Constants::TRUE or WebService::Gdata::Constants::FALSE

    Returns

    WebService::GData::Query

    Throws

    WebService::GData::Error

    Example:

        use WebService::GData::Query;
    
        my $query = new WebService::GData::Query();
    
        $query->strict('true');
    
        $query->strict(TRUE);#better
    
        $query->strict('hello');#die

fields

    Allows you to query partial data. This is a Google data experimental feature as of this version.

    Parameters

    partial_query:Scalar

    Returns

    WebService::GData::Query

    Example:

        use WebService::GData::Query;
    
        my $query = new WebService::GData::Query();
    
        $query->fields('id,entry(author)');#only get the id and the author in the entry tag

    See Also

    The reference for the partial queries:

    http://code.google.com/intl/en/apis/gdata/docs/2.0/reference.html#PartialResponse

v

    Set the google Data API version number. Default to WebService::GData::Constants::GDATA_MINIMUM_VERSION. You shoud not set this unless you know what you do.

alt

    Specify the response format used. Default to WebService::GData::Constants::JSON. You shoud not set this unless you know what you do.

prettyprint

    If set to true (default false),the result from the service will contain indentation.

    Parameters

    true_or_false:Scalar (Default: WebService::Gdata::Constants::FALSE)

    The value can be WebService::Gdata::Constants::TRUE or WebService::Gdata::Constants::FALSE

    Returns

    WebService::GData::Query

    Throws

    WebService::GData::Error

    Example:

        use WebService::GData::Query;
    
        my $query = new WebService::GData::Query();
    
        $query->prettyprint('true');
    
        $query->prettyprint(TRUE);#better
    
        $query->prettyprint('hello');#die

author

    Specify the author of the contents you want to retrieve. Each service derives the meaning for their own feed.

    Parameters

    author_name:Scalar

    Returns

    WebService::GData::Query

    Example:

        use WebService::GData::Query;
    
        my $query = new WebService::GData::Query();
    
        $query->author('GoogleDeveloper');

updated_min

    Retrieve the contents which update date is a minimum equal to the one specified (inclusive). Note that you should retrieve the value as 'updated-min' when used with WebService::GData::Query::get().

    Parameters

    date:Scalar - Format:2005-08-09T10:57:00-08:00

    Returns

    WebService::GData::Query

    Throws

    WebService::GData::Error

updated_max

    Retrieve the contents which update date is at maximum equal to the one specified (exclusive). Note that you should retrieve the value as 'updated-max' when used with WebService::GData::Query::get().

    Parameters

    date:Scalar - Format:2005-08-09T10:57:00-08:00

    Returns

    WebService::GData::Query

    Throws

    WebService::GData::Error

published_min

    Retrieve the contents which publish date is a minimum equal to the one specified (inclusive). Note that you should retrieve the value as 'published-min' when used with WebService::GData::Query::get().

    Parameters

    date:Scalar - Format:2005-08-09T10:57:00-08:00

    Returns

    WebService::GData::Query

    Throws

    WebService::GData::Error

published_max

    Retrieve the contents which publish date is a maximum equal to the one specified (exclusive). Note that you should retrieve the value as 'published-max' when used with WebService::GData::Query::get().

    Parameters

    date:Scalar - Format:2005-08-09T10:57:00-08:00

    Returns

    WebService::GData::Query

    Throws

    WebService::GData::Error

start_index

    Retrieve the contents starting from a certain result. Start from 1. Setting 0 will revert to 1. Note that you should retrieve the value as 'start-index' when used with WebService::GData::Query::get().

    Parameters

    index_number:Int - Setting the number to 0 or anything but an integer will coerce it to 1.

    Returns

    WebService::GData::Query

max_results

    Retrieve the contents up to a certain amount of entry (Most of the services set it to 25 by default).

    Note that you should retrieve the value as 'max-results' when used with WebService::GData::Query::get().

    Parameters

    index_number:Int - Setting the number to 0 or anything but an integer will coerce it to 1.

    Returns

    WebService::GData::Query

limit

    An extension that allows you to set start_index and max_results in one method call: get('limit') will return undef. Follow the same coercicion logic of start_index and max_results.

    Parameters

    max_results:Int - The number of result you want to get back
    start_index:Int - The offset from where to start

    Returns

    WebService::GData::Query

    Example:

        use WebService::GData::Query;
    
        my $query = new WebService::GData::Query();
    
        $query->limit(10,5);
        #equivalent to
        $query->max_results(10)->start_index(5);    

q

    Insensitive freewords search where:

    • words in quotation means exact match:"word1 word2"

    • words separated by a space means AND:word1 word2

    • words prefixed with an hyphen means NOT(containing):-word1

    Parameters

    search:Scalar

    Returns

    WebService::GData::Query

    Example:

        use WebService::GData::Query;
    
        
        my $query = new WebService::GData::Query();
    
        $query->q('"exact phrase" snowbaord sports -ski');

category

    Allow to narrow down the result to specifics categories.

    • words separated by a comma(,) means AND:word1,word2

    • words separated by a pipe(|) means OR:word1|word2

    • words prefixed by an hyphen(-) are disgarded:-word1

    Parameters

    category:Scalar

    Returns

    WebService::GData::Query

    Example:

        use WebService::GData::Query;
    
        my $query = new WebService::GData::Query();
    
        $query->category('-Shows,Entertainment|Sports');

SEE ALSO

Documentation of the parameters:

http://code.google.com/intl/en/apis/gdata/docs/2.0/reference.html#Queries

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.




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