trusty (3) Weather::Com::Cached.3pm.gz
NAME
Weather::Com::Cached - Perl extension for getting weather information from weather.com
SYNOPSIS
use Data::Dumper;
use Weather::Com::Cached;
# define parameters for weather search
my %params = (
'cache' => '/tmp/weathercache',
'current' => 1,
'forecast' => 3,
'links' => 1,
'units' => 's',
'proxy' => 'http://proxy.sonstwo.de',
'timeout' => 250,
'debug' => 1,
'partner_id' => 'somepartnerid',
'license' => '12345678',
);
# instantiate a new weather.com object
my $cached_weather = Weather::Com::Cached->new(%params);
# search for locations called 'Heidelberg'
my $locations = $cached_weather->search('Heidelberg')
or die "No location found!\n";
# and then get the weather for each location found
foreach (keys %{$locations}) {
my $weather = $cached_weather->get_weather($_);
print Dumper($weather);
}
DESCRIPTION
Weather::Com::Cached is a Perl module that provides low level OO interface to gather all weather
information that is provided by weather.com.
Please refer to Weather::Com for the high level interfaces.
This module implements the caching business rules that apply to all applications programmed against the
xoap API of weather.com. Except from the cache parameter to be used while instantiating a new object
instance, this module has the same API than Weather::Com::Base. It's only a simple caching wrapper
around it.
The caching mechanism for location searches is very simple. We assume that location codes on weather.com
will never change. Therefore, a search string that has been successfully used once to search for
locations will never cause another search on the web. Each location search results will be stored in the
file "locations.dat". If you want to refresh your locations cache, simply delete this file.
Although it's really simple, the module uses Storable methods lock_store and lock_retrieve to implement
shared locking for reading cache files and exclusive locking for writing to chache files. By this way
the same cache files should be able to be used by several application instances using
Weather::Com::Cached.
You'll need to register at weather.com to to get a free partner id and a license key to be used within
all applications that you want to write against weather.com's xoap interface.
<http://www.weather.com/services/xmloap.html>
CHANGES
The location caching mechanism has been extended with version 0.4. Up to V0.4 searches were stored this
way:
$locations_cache = {
'New York' => {
'USNY1000' => 'New York/La Guardia Arpt, NY',
'USNY0998' => 'New York/Central Park, NY',
'USNY0999' => 'New York/JFK Intl Arpt, NY',
'USNY0996' => 'New York, NY'
},
}
This has changed the way it does not only store a
search_string => locations
hash. The cache now also stores a hash for each location name found:
$locations_cache => {
'new york' => {
'USNY1000' => 'New York/La Guardia Arpt, NY',
'USNY0998' => 'New York/Central Park, NY',
'USNY0999' => 'New York/JFK Intl Arpt, NY',
'USNY0996' => 'New York, NY'
},
'new york/central park, ny' => {
'USNY0998' => 'New York/Central Park, NY'
},
'new york/la guardia arpt, ny' => {
'USNY1000' => 'New York/La Guardia Arpt, NY'
},
'new york, ny' => {
'USNY0996' => 'New York, NY'
},
'new york/jfk intl arpt, ny' => {
'USNY0999' => 'New York/JFK Intl Arpt, NY'
},
}
The new mechanism has the following advantages:
1. The new chaching mechanism is case insensitive
2. This caching mechanism is a workaround one problem with weather.com's XOAP API.
Their server does not understand any search string with a '/' in it - no matter wether the '/' is URL
encoded or not!
This way, if you have searched for New York once, you'll then also get a result for direct calls to
New York/Jfk Intl Arpt, NY.
3. The new mechanism also allows searches for slashed substrings. A search for York/Central will return
the New York/Central Park, NY location and if you simply search York, you'll get anything containing
York. No matter if it's in the cache or not.
Only if you specify exactly the name of a location in the cache, only this location is shown.
CONSTRUCTOR
new(hash or hashref)
This constructor takes the same hash or hashref as Weather::Com::Base does. Please refer to that
documentation for further details.
Except from the Weather::Com::Base's parameters this constructor takes a parameter cache which defines
the path to a directory into which all cache files will be put.
The cache directory defaults to '.'.
METHODS
search(search string)
The "search()" method has the same interface as the one of Weather::Com::Base. The difference is made by
the caching.
The search is performed in the following order:
1. If there's a direct match in the locations cache, return the locations from the cache.
2. If not, if there's a direct match on the web, return the locations found on the web and write the
search result to the cache.
3. If not, try a regexp search over all cached search strings and location names. This will return each
location that matches the search string.
The rest is all the same as for Weather::Com::Base.
SEE ALSO
See also documentation of Weather::Com and Weather::Com::Base.
AUTHOR
Thomas Schnuecker, <thomas@schnuecker.de>
COPYRIGHT AND LICENSE
Copyright (C) 2004-2007 by Thomas Schnuecker
This library is free software; you can redistribute it and/or modify it under the same terms as Perl
itself.
The data provided by weather.com and made accessible by this OO interface can be used for free under
special terms. Please have a look at the application programming guide of weather.com!
<http://www.weather.com/services/xmloap.html>