HTTP::Exception(3) User Contributed Perl Documentation HTTP::Exception(3)NAMEHTTP::Exception - throw HTTP-Errors as (Exception::Class-) Exceptions
VERSION
0.04001
SYNOPSISHTTP::Exception lets you throw HTTP-Errors as Exceptions.
use HTTP::Exception;
# throw a 404 Exception
HTTP::Exception->throw(404);
# later in your framework
eval { ... };
if (my $e = HTTP::Exception->caught) {
# do some errorhandling stuff
print $e->code; # 404
print $e->status_message; # Not Found
}
You can also throw HTTP::Exception-subclasses like this.
# same 404 Exception
eval { HTTP::Exception::404->throw(); };
eval { HTTP::Exception::NOT_FOUND->throw(); };
And catch them accordingly.
# same 404 Exception
eval { HTTP::Exception::404->throw(); };
if (my $e = HTTP::Exception::405->caught) { do stuff } # won't catch
if (my $e = HTTP::Exception::404->caught) { do stuff } # will catch
if (my $e = HTTP::Exception::NOT_FOUND->caught) { do stuff } # will catch
if (my $e = HTTP::Exception::4XX->caught) { do stuff } # will catch all 4XX Exceptions
if (my $e = HTTP::Exception->caught) { do stuff } # will catch every HTTP::Exception
if (my $e = Exception::Class->caught) { do stuff } # catch'em all
You can create Exceptions and not throw them, because maybe you want to
set some fields manually. See "FIELDS" in HTTP::Exception and
"ACCESSORS" in HTTP::Exception for more info.
# is not thrown, ie doesn't die, only created
my $e = HTTP::Exception->new(404);
# usual stuff works
$e->code; # 404
$e->status_message # Not Found
# set status_message to something else
$e->status_message('Nothing Here')
# fails, because code is only an accessor, see section ACCESSORS below
# $e->code(403);
# and finally throw our prepared exception
$e->throw;
DESCRIPTION
Every HTTP::Exception is a Exception::Class - Class. So the same
mechanisms apply as with Exception::Class-classes. In fact have a look
at Exception::Class' docs for more general information on exceptions
and Exception::Class::Base for information on what methods a caught
exception also has.
HTTP::Exception is only a factory for HTTP::Exception::XXX (where X is
a number) subclasses. That means that HTTP::Exception->new(404) returns
a HTTP::Exception::404 object, which in turn is a HTTP::Exception::Base
- Object.
Don't bother checking a caught HTTP::Exception::...-class with "isa" as
it might not contain what you would expect. Use the code- or
status_message-attributes and the is_ -methods instead.
The subclasses are created at compile-time, ie the first time you make
"use HTTP::Exception". See paragraph below for the naming scheme of
those subclasses.
Subclassing the subclasses works as expected.
NAMING SCHEME
HTTP::Exception::XXX
X is a Number and XXX is a valid HTTP-Statuscode. All HTTP-Statuscodes
are supported. See chapter "COMPLETENESS" in HTTP::Exception
HTTP::Exception::STATUS_MESSAGE
STATUS_MESSAGE is the same name as a HTTP::Status Constant WITHOUT the
HTTP_ at the beginning. So see "CONSTANTS" in HTTP::Status for more
details.
IMPORTING SPECIFIC ERROR RANGES
It is possible to load only specific ranges of errors. For example
use HTTP::Exceptionqw(5XX);
HTTP::Exception::500->throw; # works
HTTP::Exception::400->throw; # won't work anymore
will only create HTTP::Exception::500 till HTTP::Exception::510. In
theory this should save some memory, but I don't have any numbers, that
back up this claim.
You can load multiple ranges
use HTTP::Exception qw(3XX 4XX 5XX);
And there are aliases for ranges
use HTTP::Exceptionqw(CLIENT_ERROR)
The following aliases exist and load the specified ranges:
REDIRECTION => 3XX
CLIENT_ERROR => 4XX
SERVER_ERROR => 5XX
ERROR => 4XX 5XX
ALL => 1XX 2XX 3XX 4XX 5XX
And of course, you can load multiple aliased ranges
use HTTP::Exception qw(REDIRECTION ERROR)
ALL is the same as not specifying any specific range.
# the same
use HTTP::Exceptionqw(ALL);
use HTTP::Exception;
ACCESSORS (READONLY)
code
A valid HTTP-Statuscode. See HTTP::Status for information on what codes
exist.
is_info
Return TRUE if "$self-"code> is an Informational status code (1xx).
This class of status code indicates a provisional response which can't
have any content.
is_success
Return TRUE if "$self-"code> is a Successful status code (2xx).
is_redirect
Return TRUE if "$self-"code> is a Redirection status code (3xx). This
class if status code indicates that further action needs to be taken by
the user agent in order to fulfill the request.
is_error
Return TRUE if "$self-"code> is an Error status code (4xx or 5xx). The
function return TRUE for both client error or a server error status
codes.
is_client_error
Return TRUE if "$self-"code> is an Client Error status code (4xx). This
class of status code is intended for cases in which the client seems to
have erred.
is_server_error
Return TRUE if "$self-"code> is an Server Error status code (5xx). This
class of status codes is intended for cases in which the server is
aware that it has erred or is incapable of performing the request.
POD for is_ methods is Copy/Pasted from HTTP::Status, so check back
there and alert me of changes.
FIELDS
Fields are the same as ACCESSORS except they can be set. Either you set
them during Exception creation (->new) or Exception throwing (->throw).
HTTP::Exception->new(200, status_message => "Everything's fine");
HTTP::Exception::200->new(status_message => "Everything's fine");
HTTP::Exception::OK->new(status_message => "Everything's fine");
HTTP::Exception->throw(200, status_message => "Everything's fine");
HTTP::Exception::200->throw(status_message => "Everything's fine");
HTTP::Exception::OK->throw(status_message => "Everything's fine");
Catch them in your Webframework like this
eval { ... }
if (my $e = HTTP::Exception->caught) {
print $e->code; # 200
print $e->status_message # "Everything's fine" instead of the usual ok
}
status_message
DEFAULT The HTTP-Statusmessage as provided by HTTP::Status
A Message, that represents the Execptions' Status for Humans.
PLACKHTTP::Exception can be used with Plack::Middleware::HTTPExceptions. But
HTTP::Exception does not depend on Plack, you can use it anywhere else.
It just plays nicely with Plack.
COMPLETENESS
For the sake of completeness, HTTP::Exception provides exceptions for
non-error-http-statuscodes. This means you can do
HTTP::Exception->throw(200);
which throws an Exception of type OK. Maybe useless, but complete. A
more realworld-example would be a redirection
# all are exactly the same
HTTP::Exception->throw(301, location => 'google.com');
HTTP::Exception::301->throw(location => 'google.com');
HTTP::Exception::MOVED_PERMANENTLY->throw(location => 'google.com');
CAVEATS
The HTTP::Exception-Subclass-Creation relies on HTTP::Status. It's
possible that the Subclasses change, when HTTP::Status' constants are
changed.
New Subclasses are created automatically, when constants are added to
HTTP::Status. That means in turn, that Subclasses disappear, when
constants are removed from HTTP::Status.
Some constants were added to HTTP::Status' in February 2012. As a
result HTTP::Exception broke. But that was the result of uncareful
coding on my side. I think, that breaking changes are now quite
unlikely.
AUTHOR
Thomas Mueller, "<tmueller at cpan.org>"
SEE ALSO
Exception::Class, Exception::Class::Base
Consult Exception::Class' documentation for the Exception-Mechanism and
Exception::Class::Base' docs for a list of methods our caught Exception
is also capable of.
HTTP::Status
Constants, Statuscodes and Statusmessages
Plack, especially Plack::Middleware::HTTPExceptions
Have a look at Plack, because it rules in general. In the first place,
this Module was written as the companion for
Plack::Middleware::HTTPExceptions, but since it doesn't depend on
Plack, you can use it anywhere else, too.
BUGS
Please report any bugs or feature requests to "bug-http-exception at
rt.cpan.org", or through the web interface at
http://rt.cpan.org/NoAuth/ReportBug.html?Queue=HTTP-Exception
<http://rt.cpan.org/NoAuth/ReportBug.html?Queue=HTTP-Exception>. I
will be notified, and then you'll automatically be notified of progress
on your bug as I make changes.
SUPPORT
You can find documentation for this module with the perldoc command.
perldoc HTTP::Exception
You can also look for information at:
· RT: CPAN's request tracker
http://rt.cpan.org/NoAuth/Bugs.html?Dist=HTTP-Exception
<http://rt.cpan.org/NoAuth/Bugs.html?Dist=HTTP-Exception>
· AnnoCPAN: Annotated CPAN documentation
http://annocpan.org/dist/HTTP-Exception
<http://annocpan.org/dist/HTTP-Exception>
· CPAN Ratings
http://cpanratings.perl.org/d/HTTP-Exception
<http://cpanratings.perl.org/d/HTTP-Exception>
· Search CPAN
https://metacpan.org/release/HTTP-Exception
<https://metacpan.org/release/HTTP-Exception>
LICENSE AND COPYRIGHT
Copyright 2010 Thomas Mueller.
This program is free software; you can redistribute it and/or modify it
under the terms of either: the GNU General Public License as published
by the Free Software Foundation; or the Artistic License.
See http://dev.perl.org/licenses/ for more information.
perl v5.14.2 2012-02-24 HTTP::Exception(3)
