Bio
WebAgent
Summary
Bio::WebAgent - A base class for Web (any protocol) access
Package variables
No package variables defined.
Included modules
Inherit
Synopsis
# This is a abstract superclass for bioperl modules accessing web
# resources - normally you do not instantiate it but one of its
# subclasess.
Description
This abstact superclass is a subclass of
LWP::UserAgent which
allows protocol independent access of accessing remote locations over
the Net.
It takes care of error handling, proxies and various net protocols.
BioPerl classes accessing net should inherit from it. For details,
see
LWP::UserAgent.
The interface is still eveolving. For now, I've copied over two public
methods from Bio::DB::WebDBSeqI: delay() and delay_policy. These are
used to prevent overwhelming the server by rapidly repeated . Ideally
there should be a common abstract superclass with these. See
delay.
Methods
Methods description
Usage : $agent->url
Returns : URL to reach out to Net
Args : string |
Title : delay
Usage : $secs = $self->delay([$secs])
Function: get/set number of seconds to delay between fetches
Returns : number of seconds to delay
Args : new value
NOTE: the default is to use the value specified by delay_policy().
This can be overridden by calling this method, or by passing the
-delay argument to new(). |
Title : delay_policy
Usage : $secs = $self->delay_policy
Function: return number of seconds to delay between calls to remote db
Returns : number of seconds to delay
Args : none
NOTE: The default delay policy is 3s. Override in subclasses to
implement other delays. The timer has only second resolution, so the delay
will actually be +/- 1s. |
Title : sleep
Usage : $self->sleep
Function: sleep for a number of seconds indicated by the delay policy
Returns : none
Args : none
NOTE: This method keeps track of the last time it was called and only
imposes a sleep if it was called more recently than the delay_policy()
allows. |
Methods code
BEGIN { $Revision = q$$Id: WebAgent.pm,v 1.4 2003/06/04 08:36:35 heikki Exp $; } | sub new
{ my $class = shift;
my $self = $class->SUPER::new();
while( @_ ) {
my $key = shift;
$key =~ s/^-//;
$self->$key(shift);
}
return $self;
} | sub url
{ my ($self,$value) = @_;
if( defined $value) {
$self->{'_url'} = $value;
}
return $self->{'_url'};} | sub delay
{ my ($self, $value) = @_;
if ($value) {
$self->throw("Need a positive integer, not [$value]")
unless $value >= 0;
$self->{'_delay'} = int $value;
}
return $self->{'_delay'} || $self->delay_policy;} | sub delay_policy
{ my $self = shift;
return 3; } | sub sleep
{ my $self = shift;
$LAST_INVOCATION_TIME ||= 0;
if (time - $LAST_INVOCATION_TIME < $self->delay) {
my $delay = $self->delay - (time - $LAST_INVOCATION_TIME);
warn "sleeping for $delay seconds\n" if $self->verbose > 0;
sleep $delay;
}
$LAST_INVOCATION_TIME = time;} | General documentation
User feedback is an integral part of the evolution of this and other
Bioperl modules. Send your comments and suggestions preferably to
the Bioperl mailing list. Your participation is much appreciated.
bioperl-l@bioperl.org - General discussion
http://bioperl.org/MailList.shtml - About the mailing lists
Report bugs to the Bioperl bug tracking system to help us keep track
of the bugs and their resolution. Bug reports can be submitted via
email or the web:
bioperl-bugs@bioperl.org
http://bioperl.org/bioperl-bugs/
Copyright (c) 2003, Heikki Lehvaslaiho and EMBL-EBI.
All Rights Reserved.
This module is free software; you can redistribute it and/or modify
it under the same terms as Perl itself.
This software is provided "as is" without warranty of any kind.
This is actually the main documentation...