5 use warnings::illegalproto ();
7 use Web::Dispatch::Wrapper ();
9 our $VERSION = '0.008';
12 my ($class, $app_package) = @_;
13 $app_package ||= caller;
14 $class->_export_into($app_package);
15 eval "package $app_package; use Web::Dispatch::Wrapper; use Moo; 1"
16 or die "Failed to setup app package: $@";
18 warnings::illegalproto->unimport;
22 my ($class, $app_package) = @_;
25 *{"${app_package}::PSGI_ENV"} = sub () { -1 };
26 require Web::Simple::Application;
27 unshift(@{"${app_package}::ISA"}, 'Web::Simple::Application');
29 (my $name = $app_package) =~ s/::/\//g;
30 $INC{"${name}.pm"} = 'Set by "use Web::Simple;" invocation';
35 Web::Simple - A quick and easy way to build simple web applications
42 use Web::Simple 'HelloWorld';
47 sub dispatch_request {
49 [ 200, [ 'Content-type', 'text/plain' ], [ 'Hello world!' ] ]
52 [ 405, [ 'Content-type', 'text/plain' ], [ 'Method not allowed' ] ]
57 HelloWorld->run_if_script;
59 If you save this file into your cgi-bin as C<hello-world.cgi> and then visit:
61 http://my.server.name/cgi-bin/hello-world.cgi/
63 you'll get the "Hello world!" string output to your browser. For more complex
64 examples and non-CGI deployment, see below. To get help with L<Web::Simple>,
65 please connect to the irc.perl.org IRC network and join #web-simple.
69 The philosophy of L<Web::Simple> is to keep to an absolute bare minimum for
70 everything. It is not designed to be used for large scale applications;
71 the L<Catalyst> web framework already works very nicely for that and is
72 a far more mature, well supported piece of software.
74 However, if you have an application that only does a couple of things, and
75 want to not have to think about complexities of deployment, then L<Web::Simple>
76 might be just the thing for you.
78 The only public interface the L<Web::Simple> module itself provides is an
81 use Web::Simple 'NameOfApplication';
83 This sets up your package (in this case "NameOfApplication" is your package)
84 so that it inherits from L<Web::Simple::Application> and imports L<strictures>,
85 as well as installs a C<PSGI_ENV> constant for convenience, as well as some
88 Importing L<strictures> will automatically make your code use the C<strict> and
89 C<warnings> pragma, so you can skip the usual:
92 use warnings FATAL => 'aa';
94 provided you 'use Web::Simple' at the top of the file. Note that we turn
95 on *fatal* warnings so if you have any warnings at any point from the file
96 that you did 'use Web::Simple' in, then your application will die. This is,
97 so far, considered a feature.
99 When we inherit from L<Web::Simple::Application> we also use L<Moo>, which is
100 the the equivalent of:
103 package NameOfApplication;
105 extends 'Web::Simple::Application';
108 So you can use L<Moo> features in your application, such as creating attributes
109 using the C<has> subroutine, etc. Please see the documentation for L<Moo> for
112 It also exports the following subroutines for use in dispatchers:
114 response_filter { ... };
116 redispatch_to '/somewhere';
120 $INC{"NameOfApplication.pm"} = 'Set by "use Web::Simple;" invocation';
122 so that perl will not attempt to load the application again even if
124 require NameOfApplication;
126 is encountered in other code.
128 =head1 DISPATCH STRATEGY
130 L<Web::Simple> despite being straightforward to use, has a powerful system
131 for matching all sorts of incoming URLs to one or more subroutines. These
132 subroutines can be simple actions to take for a given URL, or something
133 more complicated, including entire L<Plack> applications, L<Plack::Middleware>
134 and nested subdispatchers.
138 sub dispatch_request {
139 # matches: GET /user/1.htm?show_details=1
141 sub (GET + /user/* + ?show_details~ + .htm|.html|.xhtml) {
142 my ($self, $user_id, $show_details) = @_;
145 # matches: POST /user?username=frew
146 # POST /user?username=mst&first_name=matt&last_name=trout
147 sub (POST + /user + ?username=&*) {
148 my ($self, $username, $misc_params) = @_;
151 # matches: DELETE /user/1/friend/2
152 sub (DELETE + /user/*/friend/*) {
153 my ($self, $user_id, $friend_id) = @_;
156 # matches: PUT /user/1?first_name=Matt&last_name=Trout
157 sub (PUT + /user/* + ?first_name~&last_name~) {
158 my ($self, $user_id, $first_name, $last_name) = @_;
163 # matches: PUT /user/1/role/1
164 sub (PUT + /role/*) {
168 # matches: DELETE /user/1/role/1
169 sub (DELETE + /role/*) {
176 =head2 The dispatch cycle
178 At the beginning of a request, your app's dispatch_request method is called
179 with the PSGI $env as an argument. You can handle the request entirely in
180 here and return a PSGI response arrayref if you want:
182 sub dispatch_request {
183 my ($self, $env) = @_;
184 [ 404, [ 'Content-type' => 'text/plain' ], [ 'Amnesia == fail' ] ]
187 However, generally, instead of that, you return a set of dispatch subs:
189 sub dispatch_request {
191 sub (/) { redispatch_to '/index.html' },
192 sub (/user/*) { $self->show_user($_[1]) },
196 If you return a subroutine with a prototype, the prototype is treated
197 as a match specification - and if the test is passed, the body of the
198 sub is called as a method any matched arguments (see below for more details).
200 You can also return a plain subroutine which will be called with just $env
201 - remember that in this case if you need $self you -must- close over it.
203 If you return a normal object, L<Web::Simple> will simply return it upwards on
204 the assumption that a response_filter (or some arbitrary L<Plack::Middleware>)
205 somewhere will convert it to something useful. This allows:
207 sub dispatch_request {
209 sub (.html) { response_filter { $self->render_zoom($_[0]) } },
210 sub (/user/*) { $self->users->get($_[1]) },
213 to render a user object to HTML, if there is an incoming URL such as:
215 http://myweb.org/user/111.html
217 This works because as we descend down the dispachers, we first match
218 C<sub (.html)>, which adds a C<response_filter> (basically a specialized routine
219 that follows the L<Plack::Middleware> specification), and then later we also
220 match C<sub (/user/*)> which gets a user and returns that as the response.
221 This user object 'bubbles up' through all the wrapping middleware until it hits
222 the C<response_filter> we defined, after which the return is converted to a
225 However, two types of object are treated specially - a Plack::App object
226 will have its C<->to_app> method called and be used as a dispatcher:
228 sub dispatch_request {
230 sub (/static/...) { Plack::App::File->new(...) },
234 A Plack::Middleware object will be used as a filter for the rest of the
235 dispatch being returned into:
237 ## responds to /admin/track_usage AND /admin/delete_accounts
239 sub dispatch_request {
242 Plack::Middleware::Session->new(%opts);
244 sub (/admin/track_usage) {
245 ## something that needs a session
247 sub (/admin/delete_accounts) {
248 ## something else that needs a session
252 Note that this is for the dispatch being -returned- to, so if you want to
253 provide it inline you need to do:
255 ## ALSO responds to /admin/track_usage AND /admin/delete_accounts
257 sub dispatch_request {
261 Plack::Middleware::Session->new(%opts);
264 ## something that needs a session
266 sub (/delete_accounts) {
267 ## something else that needs a session
272 And that's it - but remember that all this happens recursively - it's
273 dispatchers all the way down. A URL incoming pattern will run all matching
274 dispatchers and then hit all added filters or L<Plack::Middleware>.
276 =head2 Web::Simple match specifications
278 =head3 Method matches
282 A match specification beginning with a capital letter matches HTTP requests
283 with that request method.
289 A match specification beginning with a / is a path match. In the simplest
290 case it matches a specific path. To match a path with a wildcard part, you
294 $self->handle_user($_[1])
296 This will match /user/<anything> where <anything> does not include a literal
297 / character. The matched part becomes part of the match arguments. You can
298 also match more than one part:
301 my ($self, $user_1, $user_2) = @_;
303 sub (/domain/*/user/*) {
304 my ($self, $domain, $user) = @_;
306 and so on. To match an arbitrary number of parts, use -
310 This will result in an element per /-separated part so matched. Note that
313 sub (/page/**/edit) {
315 to match an arbitrary number of parts up to but not including some final
322 Will match /foo/ on the beginning of the path -and- strip it. This is designed
323 to be used to construct nested dispatch structures, but can also prove useful
324 for having e.g. an optional language specification at the start of a path.
326 Note that the '...' is a "maybe something here, maybe not" so the above
327 specification will match like this:
330 /foo/ # match and strip path to '/'
331 /foo/bar/baz # match and strip path to '/bar/baz'
333 Note: Since Web::Simple handles a concept of file extensions, * and **
334 matchers will not by default match things after a final dot, and this
335 can be modified by using *.* and **.* in the final position, i.e.:
337 /one/* matches /one/two.three and captures "two"
338 /one/*.* matches /one/two.three and captures "two.three"
339 /** matches /one/two.three and captures "one/two"
340 /**.* matches /one/two.three and captures "one/two.three"
342 =head3 Extension matches
346 will match .html from the path (assuming the subroutine itself returns
347 something, of course). This is normally used for rendering - e.g.
350 response_filter { $self->render_html($_[1]) }
357 will match any extension and supplies the extension as a match argument.
359 =head3 Query and body parameter matches
361 Query and body parameters can be match via
363 sub (?<param spec>) { # match URI query
364 sub (%<param spec>) { # match body params
366 The body is only matched if the content type is
367 application/x-www-form-urlencoded (note this means that Web::Simple does
368 not yet handle uploads; this will be addressed in a later release).
370 The param spec is elements of one of the following forms -
372 param~ # optional parameter
373 param= # required parameter
374 @param~ # optional multiple parameter
375 @param= # required multiple parameter
376 :param~ # optional parameter in hashref
377 :param= # required parameter in hashref
378 :@param~ # optional multiple in hashref
379 :@param= # required multiple in hashref
380 * # include all other parameters in hashref
381 @* # include all other parameters as multiple in hashref
383 separated by the & character. The arguments added to the request are
384 one per non-:/* parameter (scalar for normal, arrayref for multiple),
385 plus if any :/* specs exist a hashref containing those values.
387 Please note that if you specify a multiple type parameter match, you are
388 ensured of getting an arrayref for the value, EVEN if the current incoming
389 request has only one value. However if a parameter is specified as single
390 and multiple values are found, the last one will be used.
392 For example to match a page parameter with an optional order_by parameter one
395 sub (?page=&order_by~) {
396 my ($self, $page, $order_by) = @_;
397 return unless $page =~ /^\d+$/;
400 $_[1]->search_rs({}, $p);
404 to implement paging and ordering against a L<DBIx::Class::ResultSet> object.
406 Another Example: To get all parameters as a hashref of arrayrefs, write:
409 my ($self, $params) = @_;
412 To get two parameters as a hashref, write:
414 sub(?:user~&:domain~) {
415 my ($self, $params) = @_; # params contains only 'user' and 'domain' keys
417 You can also mix these, so:
419 sub (?foo=&@bar~&:coffee=&@*) {
420 my ($self, $foo, $bar, $params);
422 where $bar is an arrayref (possibly an empty one), and $params contains
423 arrayref values for all parameters -not- mentioned and a scalar value for
424 the 'coffee' parameter.
426 Note, in the case where you combine arrayref, single parameter and named
427 hashref style, the arrayref and single parameters will appear in C<@_> in the
428 order you defined them in the protoype, but all hashrefs will merge into a
429 single C<$params>, as in the example above.
431 =head3 Upload matches (EXPERIMENTAL)
433 Note: This feature is experimental. This means that it may not remain
434 100% in its current form. If we change it, notes on updating your code
435 will be added to the L</CHANGES BETWEEN RELEASES> section below.
437 sub (*foo=) { # param specifier can be anything valid for query or body
439 The upload match system functions exactly like a query/body match, except
440 that the values returned (if any) are C<Web::Dispatch::Upload> objects.
442 Note that this match type will succeed in two circumstances where you might
443 not expect it to - first, when the field exists but is not an upload field
444 and second, when the field exists but the form is not an upload form (i.e.
445 content type "application/x-www-form-urlencoded" rather than
446 "multipart/form-data"). In either of these cases, what you'll get back is
447 a C<Web::Dispatch::NotAnUpload> object, which will C<die> with an error
448 pointing out the problem if you try and use it. To be sure you have a real
451 $upload->is_upload # returns 1 on a valid upload, 0 on a non-upload field
453 and to get the reason why such an object is not an upload, call
455 $upload->reason # returns a reason or '' on a valid upload.
457 Other than these two methods, the upload object provides the same interface
458 as L<Plack::Request::Upload> with the addition of a stringify to the temporary
459 filename to make copying it somewhere else easier to handle.
461 =head3 Combining matches
463 Matches may be combined with the + character - e.g.
465 sub (GET + /user/*) {
467 to create an AND match. They may also be combined withe the | character - e.g.
471 to create an OR match. Matches can be nested with () - e.g.
473 sub ((GET|POST) + /user/*) {
475 and negated with ! - e.g.
477 sub (!/user/foo + /user/*) {
479 ! binds to the immediate rightmost match specification, so if you want
480 to negate a combination you will need to use
482 sub ( !(POST|PUT|DELETE) ) {
484 and | binds tighter than +, so
486 sub ((GET|POST) + /user/*) {
490 sub (GET|POST + /user/*) {
494 sub ((GET + /admin/...) | (POST + /admin/...)) {
498 sub (GET + /admin/... | POST + /admin/...) {
500 are not - the latter is equivalent to
502 sub (GET + (/admin/...|POST) + /admin/...) {
504 which will never match!
508 Note that for legibility you are permitted to use whitespace -
510 sub (GET + /user/*) {
512 but it will be ignored. This is because the perl parser strips whitespace
513 from subroutine prototypes, so this is equivalent to
517 =head3 Accessing the PSGI env hash
519 In some cases you may wish to get the raw PSGI env hash - to do this,
520 you can either use a plain sub -
527 or use the PSGI_ENV constant exported to retrieve it:
529 sub (GET + /foo + ?some_param=) {
531 my $env = $_[PSGI_ENV];
534 but note that if you're trying to add a middleware, you should simply use
535 Web::Simple's direct support for doing so.
537 =head1 EXPORTED SUBROUTINES
539 =head2 response_filter
542 # Hide errors from the user because we hates them, preciousss
543 if (ref($_[0]) eq 'ARRAY' && $_[0]->[0] == 500) {
544 $_[0] = [ 200, @{$_[0]}[1..$#{$_[0]}] ];
549 The response_filter subroutine is designed for use inside dispatch subroutines.
551 It creates and returns a special dispatcher that always matches, and calls
552 the block passed to it as a filter on the result of running the rest of the
553 current dispatch chain.
555 Thus the filter above runs further dispatch as normal, but if the result of
556 dispatch is a 500 (Internal Server Error) response, changes this to a 200 (OK)
557 response without altering the headers or body.
561 redispatch_to '/other/url';
563 The redispatch_to subroutine is designed for use inside dispatch subroutines.
565 It creates and returns a special dispatcher that always matches, and instead
566 of continuing dispatch re-delegates it to the start of the dispatch process,
567 but with the path of the request altered to the supplied URL.
569 Thus if you receive a POST to '/some/url' and return a redispatch to
570 '/other/url', the dispatch behaviour will be exactly as if the same POST
571 request had been made to '/other/url' instead.
573 Note, this is not the same as returning an HTTP 3xx redirect as a response;
574 rather it is a much more efficient internal process.
576 =head1 CHANGES BETWEEN RELEASES
578 =head2 Changes between 0.004 and 0.005
582 =item * dispatch {} replaced by declaring a dispatch_request method
584 dispatch {} has gone away - instead, you write:
586 sub dispatch_request {
588 sub (GET /foo/) { ... },
592 Note that this method is still -returning- the dispatch code - just like
595 Also note that you need the 'my $self = shift' since the magic $self
598 =item * the magic $self variable went away.
600 Just add 'my $self = shift;' while writing your 'sub dispatch_request {'
601 like a normal perl method.
603 =item * subdispatch deleted - all dispatchers can now subdispatch
605 In earlier releases you needed to write:
607 subdispatch sub (/foo/...) {
610 sub (GET /bar/) { ... },
615 As of 0.005, you can instead write simply:
620 sub (GET /bar/) { ... },
625 =head2 Changes since Antiquated Perl
629 =item * filter_response renamed to response_filter
631 This is a pure rename; a global search and replace should fix it.
633 =item * dispatch [] changed to dispatch {}
637 dispatch [ sub(...) { ... }, ... ];
641 dispatch { sub(...) { ... }, ... };
647 =head1 DEVELOPMENT HISTORY
649 Web::Simple was originally written to form part of my Antiquated Perl talk for
650 Italian Perl Workshop 2009, but in writing the bloggery example I realised
651 that having a bare minimum system for writing web applications that doesn't
652 drive me insane was rather nice and decided to spend my attempt at nanowrimo
653 for 2009 improving and documenting it to the point where others could use it.
655 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
656 L<Web::Simple::AntiquatedPerl>.
658 =head1 COMMUNITY AND SUPPORT
662 irc.perl.org #web-simple
664 =head2 No mailing list yet
666 Because mst's non-work email is a bombsite so he'd never read it anyway.
668 =head2 Git repository
670 Gitweb is on http://git.shadowcat.co.uk/ and the clone URL is:
672 git clone git://git.shadowcat.co.uk/catagits/Web-Simple.git
676 Matt S. Trout <mst@shadowcat.co.uk>
680 None required yet. Maybe this module is perfect (hahahahaha ...).
684 Copyright (c) 2010 the Web::Simple L</AUTHOR> and L</CONTRIBUTORS>
689 This library is free software and may be distributed under the same terms