use strictures 1;
use 5.008;
use warnings::illegalproto ();
+use Moo ();
+use Web::Dispatch::Wrapper ();
-our $VERSION = '0.004';
+our $VERSION = '0.008';
sub import {
my ($class, $app_package) = @_;
- $class->_export_into($app_package||caller);
- eval "package $class; use Web::Dispatch::Wrapper; use Moo;";
+ $app_package ||= caller;
+ $class->_export_into($app_package);
+ eval "package $app_package; use Web::Dispatch::Wrapper; use Moo; 1"
+ or die "Failed to setup app package: $@";
strictures->import;
warnings::illegalproto->unimport;
}
=head1 SYNOPSIS
- #!/usr/bin/perl
+ #!/usr/bin/env perl
use Web::Simple 'HelloWorld';
HelloWorld->run_if_script;
-If you save this file into your cgi-bin as hello-world.cgi and then visit
+If you save this file into your cgi-bin as C<hello-world.cgi> and then visit:
http://my.server.name/cgi-bin/hello-world.cgi/
you'll get the "Hello world!" string output to your browser. For more complex
-examples and non-CGI deployment, see below. To get help with Web::Simple,
+examples and non-CGI deployment, see below. To get help with L<Web::Simple>,
please connect to the irc.perl.org IRC network and join #web-simple.
-=head1 WHY?
-
-Web::Simple was originally written to form part of my Antiquated Perl talk for
-Italian Perl Workshop 2009, but in writing the bloggery example I realised
-that having a bare minimum system for writing web applications that doesn't
-drive me insane was rather nice and decided to spend my attempt at nanowrimo
-for 2009 improving and documenting it to the point where others could use it.
+=head1 DESCRIPTION
-The philosophy of Web::Simple is to keep to an absolute bare minimum, for
+The philosophy of L<Web::Simple> is to keep to an absolute bare minimum for
everything. It is not designed to be used for large scale applications;
the L<Catalyst> web framework already works very nicely for that and is
a far more mature, well supported piece of software.
However, if you have an application that only does a couple of things, and
-want to not have to think about complexities of deployment, then Web::Simple
+want to not have to think about complexities of deployment, then L<Web::Simple>
might be just the thing for you.
-The Antiquated Perl talk can be found at L<http://www.shadowcat.co.uk/archive/conference-video/>.
-
-=head1 DESCRIPTION
-
-The only public interface the Web::Simple module itself provides is an
-import based one -
+The only public interface the L<Web::Simple> module itself provides is an
+C<import> based one:
use Web::Simple 'NameOfApplication';
-This imports 'strict' and 'warnings FATAL => "all"' into your code as well,
-so you can skip the usual
+This sets up your package (in this case "NameOfApplication" is your package)
+so that it inherits from L<Web::Simple::Application> and imports L<strictures>,
+as well as installs a C<PSGI_ENV> constant for convenience, as well as some
+other subroutines.
+
+Importing L<strictures> will automatically make your code use the C<strict> and
+C<warnings> pragma, so you can skip the usual:
use strict;
- use warnings;
+ use warnings FATAL => 'aa';
provided you 'use Web::Simple' at the top of the file. Note that we turn
on *fatal* warnings so if you have any warnings at any point from the file
that you did 'use Web::Simple' in, then your application will die. This is,
so far, considered a feature.
-Calling the import also makes NameOfApplication isa Web::Simple::Application
-and sets your app class up as a L<Moo> class- i.e. does the equivalent of
+When we inherit from L<Web::Simple::Application> we also use L<Moo>, which is
+the the equivalent of:
{
package NameOfApplication;
extends 'Web::Simple::Application';
}
+So you can use L<Moo> features in your application, such as creating attributes
+using the C<has> subroutine, etc. Please see the documentation for L<Moo> for
+more information.
+
It also exports the following subroutines for use in dispatchers:
response_filter { ... };
=head1 DISPATCH STRATEGY
+L<Web::Simple> despite being straightforward to use, has a powerful system
+for matching all sorts of incoming URLs to one or more subroutines. These
+subroutines can be simple actions to take for a given URL, or something
+more complicated, including entire L<Plack> applications, L<Plack::Middleware>
+and nested subdispatchers.
+
=head2 Examples
sub dispatch_request {
},
}
-=head2
-Description of the dispatcher object
-
-Web::Simple::Dispatcher objects have three components:
-
-=over 4
-
-=item * match - an optional test if this dispatcher matches the request
+=head2 The dispatch cycle
-=item * call - a routine to call if this dispatcher matches (or has no match)
+At the beginning of a request, your app's dispatch_request method is called
+with the PSGI $env as an argument. You can handle the request entirely in
+here and return a PSGI response arrayref if you want:
-=item * next - the next dispatcher to call
+ sub dispatch_request {
+ my ($self, $env) = @_;
+ [ 404, [ 'Content-type' => 'text/plain' ], [ 'Amnesia == fail' ] ]
+ }
-=back
+However, generally, instead of that, you return a set of dispatch subs:
-When a dispatcher is invoked, it checks its match routine against the
-request environment. The match routine may provide alterations to the
-request as a result of matching, and/or arguments for the call routine.
+ sub dispatch_request {
+ my $self = shift;
+ sub (/) { redispatch_to '/index.html' },
+ sub (/user/*) { $self->show_user($_[1]) },
+ ...
+ }
-If no match routine has been provided then Web::Simple treats this as
-a success, and supplies the request environment to the call routine as
-an argument.
+If you return a subroutine with a prototype, the prototype is treated
+as a match specification - and if the test is passed, the body of the
+sub is called as a method any matched arguments (see below for more details).
-Given a successful match, the call routine is now invoked in list context
-with any arguments given to the original dispatch, plus any arguments
-provided by the match result.
+You can also return a plain subroutine which will be called with just $env
+- remember that in this case if you need $self you -must- close over it.
-If this routine returns (), Web::Simple treats this identically to a failure
-to match.
+If you return a normal object, L<Web::Simple> will simply return it upwards on
+the assumption that a response_filter (or some arbitrary L<Plack::Middleware>)
+somewhere will convert it to something useful. This allows:
-If this routine returns a Web::Simple::Dispatcher, the environment changes
-are merged into the environment and the new dispatcher's next pointer is
-set to our next pointer.
+ sub dispatch_request {
+ my $self = shift;
+ sub (.html) { response_filter { $self->render_zoom($_[0]) } },
+ sub (/user/*) { $self->users->get($_[1]) },
+ }
-If this routine returns anything else, that is treated as the end of dispatch
-and the value is returned.
+to render a user object to HTML, if there is an incoming URL such as:
-On a failed match, Web::Simple invokes the next dispatcher with the same
-arguments and request environment passed to the current one. On a successful
-match that returned a new dispatcher, Web::Simple invokes the new dispatcher
-with the same arguments but the modified request environment.
+ http://myweb.org/user/111.html
-=head2 How Web::Simple builds dispatcher objects for you
+This works because as we descend down the dispachers, we first match
+C<sub (.html)>, which adds a C<response_filter> (basically a specialized routine
+that follows the L<Plack::Middleware> specification), and then later we also
+match C<sub (/user/*)> which gets a user and returns that as the response.
+This user object 'bubbles up' through all the wrapping middleware until it hits
+the C<response_filter> we defined, after which the return is converted to a
+true html response.
-In the case of the Web::Simple L</dispatch> export the match is constructed
-from the subroutine prototype - i.e.
+However, two types of object are treated specially - a Plack::App object
+will have its C<->to_app> method called and be used as a dispatcher:
- sub (<match specification>) {
- <call code>
+ sub dispatch_request {
+ my $self = shift;
+ sub (/static/...) { Plack::App::File->new(...) },
+ ...
}
-and the 'next' pointer is populated with the next element of the array,
-expect for the last element, which is given a next that will throw a 500
-error if none of your dispatchers match. If you want to provide something
-else as a default, a routine with no match specification always matches, so -
+A Plack::Middleware object will be used as a filter for the rest of the
+dispatch being returned into:
- sub () {
- [ 404, [ 'Content-type', 'text/plain' ], [ 'Error: Not Found' ] ]
+ ## responds to /admin/track_usage AND /admin/delete_accounts
+
+ sub dispatch_request {
+ my $self = shift;
+ sub (/admin/**) {
+ Plack::Middleware::Session->new(%opts);
+ },
+ sub (/admin/track_usage) {
+ ## something that needs a session
+ },
+ sub (/admin/delete_accounts) {
+ ## something else that needs a session
+ },
}
-will produce a 404 result instead of a 500 by default. You can also override
-the L<Web::Simple::Application/_build_final_dispatcher> method in your app.
+Note that this is for the dispatch being -returned- to, so if you want to
+provide it inline you need to do:
-Note that the code in the subroutine is executed as a -method- on your
-application object, so if your match specification provides arguments you
-should unpack them like so:
+ ## ALSO responds to /admin/track_usage AND /admin/delete_accounts
- sub (<match specification>) {
- my ($self, @args) = @_;
- ...
+ sub dispatch_request {
+ my $self = shift;
+ sub (/admin/...) {
+ sub {
+ Plack::Middleware::Session->new(%opts);
+ },
+ sub (/track_usage) {
+ ## something that needs a session
+ },
+ sub (/delete_accounts) {
+ ## something else that needs a session
+ },
+ }
}
+And that's it - but remember that all this happens recursively - it's
+dispatchers all the way down. A URL incoming pattern will run all matching
+dispatchers and then hit all added filters or L<Plack::Middleware>.
+
=head2 Web::Simple match specifications
=head3 Method matches
sub (/foo/...) {
-will match /foo/ on the beginning of the path -and- strip it, much like
-.html strips the extension. This is designed to be used to construct
-nested dispatch structures, but can also prove useful for having e.g. an
-optional language specification at the start of a path.
+Will match /foo/ on the beginning of the path -and- strip it. This is designed
+to be used to construct nested dispatch structures, but can also prove useful
+for having e.g. an optional language specification at the start of a path.
Note that the '...' is a "maybe something here, maybe not" so the above
specification will match like this:
sub (.html) {
-will match and strip .html from the path (assuming the subroutine itself
-returns something, of course). This is normally used for rendering - e.g.
+will match .html from the path (assuming the subroutine itself returns
+something, of course). This is normally used for rendering - e.g.
sub (.html) {
response_filter { $self->render_html($_[1]) }
sub (.*) {
-will match any extension and supplies the stripped extension as a match
-argument.
+will match any extension and supplies the extension as a match argument.
=head3 Query and body parameter matches
one per non-:/* parameter (scalar for normal, arrayref for multiple),
plus if any :/* specs exist a hashref containing those values.
-So, to match a page parameter with an optional order_by parameter one
+Please note that if you specify a multiple type parameter match, you are
+ensured of getting an arrayref for the value, EVEN if the current incoming
+request has only one value. However if a parameter is specified as single
+and multiple values are found, the last one will be used.
+
+For example to match a page parameter with an optional order_by parameter one
would write:
sub (?page=&order_by~) {
to implement paging and ordering against a L<DBIx::Class::ResultSet> object.
-Note that if a parameter is specified as single and multiple values are found,
-the last one will be used.
-
-To get all parameters as a hashref of arrayrefs, write:
+Another Example: To get all parameters as a hashref of arrayrefs, write:
sub(?@*) {
my ($self, $params) = @_;
arrayref values for all parameters -not- mentioned and a scalar value for
the 'coffee' parameter.
+Note, in the case where you combine arrayref, single parameter and named
+hashref style, the arrayref and single parameters will appear in C<@_> in the
+order you defined them in the protoype, but all hashrefs will merge into a
+single C<$params>, as in the example above.
+
=head3 Combining matches
Matches may be combined with the + character - e.g.
are equivalent, but
- sub ((GET + .html) | (POST + .html)) {
+ sub ((GET + /admin/...) | (POST + /admin/...)) {
and
- sub (GET + .html | POST + .html) {
+ sub (GET + /admin/... | POST + /admin/...) {
are not - the latter is equivalent to
- sub (GET + (.html|POST) + .html) {
+ sub (GET + (/admin/...|POST) + /admin/...) {
-which will never match.
+which will never match!
=head3 Whitespace
=head3 Accessing the PSGI env hash
-To gain the benefit of using some middleware, specifically
-Plack::Middleware::Session access to the ENV hash is needed. This is provided
-in arguments to the dispatched handler. You can access this hash with the
-exported PSGI_ENV constant.
+In some cases you may wish to get the raw PSGI env hash - to do this,
+you can either use a plain sub -
- sub (GET + /foo + ?some_param=) {
- my($self, $some_param, $env) = @_[0, 1, PSGI_ENV];
+ sub {
+ my ($env) = @_;
+ ...
+ }
-=head2 Dispatcher return values
+or use the PSGI_ENV constant exported to retrieve it:
-A dispatcher returns one of:
+ sub (GET + /foo + ?some_param=) {
+ my $param = $_[1];
+ my $env = $_[PSGI_ENV];
+ }
+
+but note that if you're trying to add a middleware, you should simply use
+Web::Simple's direct support for doing so.
=head1 EXPORTED SUBROUTINES
of continuing dispatch re-delegates it to the start of the dispatch process,
but with the path of the request altered to the supplied URL.
-Thus if you receive a POST to '/some/url' and return a redipstch to
+Thus if you receive a POST to '/some/url' and return a redispatch to
'/other/url', the dispatch behaviour will be exactly as if the same POST
request had been made to '/other/url' instead.
-=head2 subdispatch
-
- subdispatch sub (/user/*/) {
- my $u = $self->user($_[1]);
- [
- sub (GET) { $u },
- sub (DELETE) { $u->delete },
- ]
- }
-
-The subdispatch subroutine is designed for use in dispatcher construction.
-
-It creates a dispatcher which, if it matches, treats its return value not
-as a final value but an arrayref of dispatch specifications such as could
-be passed to the dispatch subroutine itself. These are turned into a dispatcher
-which is then invoked. Any changes the match makes to the request are in
-scope for this inner dispatcher only - so if the initial match is a
-destructive one like .html the full path will be restored if the
-subdispatch fails.
+Note, this is not the same as returning an HTTP 3xx redirect as a response;
+rather it is a much more efficient internal process.
=head1 CHANGES BETWEEN RELEASES
dispatch {} has gone away - instead, you write:
sub dispatch_request {
+ my $self = shift;
sub (GET /foo/) { ... },
...
}
Note that this method is still -returning- the dispatch code - just like
dispatch did.
+Also note that you need the 'my $self = shift' since the magic $self
+variable went away.
+
+=item * the magic $self variable went away.
+
+Just add 'my $self = shift;' while writing your 'sub dispatch_request {'
+like a normal perl method.
+
=item * subdispatch deleted - all dispatchers can now subdispatch
In earlier releases you needed to write:
=back
+=head1 DEVELOPMENT HISTORY
+
+Web::Simple was originally written to form part of my Antiquated Perl talk for
+Italian Perl Workshop 2009, but in writing the bloggery example I realised
+that having a bare minimum system for writing web applications that doesn't
+drive me insane was rather nice and decided to spend my attempt at nanowrimo
+for 2009 improving and documenting it to the point where others could use it.
+
+The Antiquated Perl talk can be found at L<http://www.shadowcat.co.uk/archive/conference-video/> and the slides are reproduced in this distribution under
+L<Web::Simple::AntiquatedPerl>.
+
=head1 COMMUNITY AND SUPPORT
=head2 IRC channel
=head1 COPYRIGHT
-Copyright (c) 2009 the Web::Simple L</AUTHOR> and L</CONTRIBUTORS>
+Copyright (c) 2010 the Web::Simple L</AUTHOR> and L</CONTRIBUTORS>
as listed above.
=head1 LICENSE
projects / catagits/Web-Simple.git / blobdiff