5 use warnings::illegalproto ();
7 use Web::Dispatch::Wrapper ();
9 our $VERSION = '0.020';
12 my ($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';
37 Web::Simple - A quick and easy way to build simple web applications
47 sub dispatch_request {
49 [ 200, [ 'Content-type', 'text/plain' ], [ 'Hello world!' ] ]
52 [ 405, [ 'Content-type', 'text/plain' ], [ 'Method not allowed' ] ]
56 HelloWorld->run_if_script;
58 If you save this file into your cgi-bin as C<hello-world.cgi> and then visit:
60 http://my.server.name/cgi-bin/hello-world.cgi/
62 you'll get the "Hello world!" string output to your browser. At the same time
63 this file will also act as a class module, so you can save it as HelloWorld.pm
64 and use it as-is in test scripts or other deployment mechanisms.
66 Note that you should retain the ->run_if_script even if your app is a
67 module, since this additionally makes it valid as a .psgi file, which can
68 be extremely useful during development.
70 For more complex examples and non-CGI deployment, see
71 L<Web::Simple::Deployment>. To get help with L<Web::Simple>, please connect to
72 the irc.perl.org IRC network and join #web-simple.
76 The philosophy of L<Web::Simple> is to keep to an absolute bare minimum for
77 everything. It is not designed to be used for large scale applications;
78 the L<Catalyst> web framework already works very nicely for that and is
79 a far more mature, well supported piece of software.
81 However, if you have an application that only does a couple of things, and
82 want to not have to think about complexities of deployment, then L<Web::Simple>
83 might be just the thing for you.
85 The only public interface the L<Web::Simple> module itself provides is an
88 use Web::Simple 'NameOfApplication';
90 This sets up your package (in this case "NameOfApplication" is your package)
91 so that it inherits from L<Web::Simple::Application> and imports L<strictures>,
92 as well as installs a C<PSGI_ENV> constant for convenience, as well as some
95 Importing L<strictures> will automatically make your code use the C<strict> and
96 C<warnings> pragma, so you can skip the usual:
99 use warnings FATAL => 'aa';
101 provided you 'use Web::Simple' at the top of the file. Note that we turn
102 on *fatal* warnings so if you have any warnings at any point from the file
103 that you did 'use Web::Simple' in, then your application will die. This is,
104 so far, considered a feature.
106 When we inherit from L<Web::Simple::Application> we also use L<Moo>, which is
107 the the equivalent of:
110 package NameOfApplication;
112 extends 'Web::Simple::Application';
115 So you can use L<Moo> features in your application, such as creating attributes
116 using the C<has> subroutine, etc. Please see the documentation for L<Moo> for
119 It also exports the following subroutines for use in dispatchers:
121 response_filter { ... };
123 redispatch_to '/somewhere';
127 $INC{"NameOfApplication.pm"} = 'Set by "use Web::Simple;" invocation';
129 so that perl will not attempt to load the application again even if
131 require NameOfApplication;
133 is encountered in other code.
135 One important thing to remember when using
137 NameOfApplication->run_if_script;
139 At the end of your app is that this call will create an instance of your app
140 for you automatically, regardless of context. An easier way to think of this
141 would be if the method were more verbosely named
143 NameOfApplication->run_request_if_script_else_turn_coderef_for_psgi;
145 =head1 DISPATCH STRATEGY
147 L<Web::Simple> despite being straightforward to use, has a powerful system
148 for matching all sorts of incoming URLs to one or more subroutines. These
149 subroutines can be simple actions to take for a given URL, or something
150 more complicated, including entire L<Plack> applications, L<Plack::Middleware>
151 and nested subdispatchers.
155 sub dispatch_request {
156 # matches: GET /user/1.htm?show_details=1
158 sub (GET + /user/* + ?show_details~ + .htm|.html|.xhtml) {
159 my ($self, $user_id, $show_details) = @_;
162 # matches: POST /user?username=frew
163 # POST /user?username=mst&first_name=matt&last_name=trout
164 sub (POST + /user + ?username=&*) {
165 my ($self, $username, $misc_params) = @_;
168 # matches: DELETE /user/1/friend/2
169 sub (DELETE + /user/*/friend/*) {
170 my ($self, $user_id, $friend_id) = @_;
173 # matches: PUT /user/1?first_name=Matt&last_name=Trout
174 sub (PUT + /user/* + ?first_name~&last_name~) {
175 my ($self, $user_id, $first_name, $last_name) = @_;
180 # matches: PUT /user/1/role/1
181 sub (PUT + /role/*) {
185 # matches: DELETE /user/1/role/1
186 sub (DELETE + /role/*) {
193 =head2 The dispatch cycle
195 At the beginning of a request, your app's dispatch_request method is called
196 with the PSGI $env as an argument. You can handle the request entirely in
197 here and return a PSGI response arrayref if you want:
199 sub dispatch_request {
200 my ($self, $env) = @_;
201 [ 404, [ 'Content-type' => 'text/plain' ], [ 'Amnesia == fail' ] ]
204 However, generally, instead of that, you return a set of dispatch subs:
206 sub dispatch_request {
208 sub (/) { redispatch_to '/index.html' },
209 sub (/user/*) { $self->show_user($_[1]) },
213 Well, a sub is a valid PSGI response too (for ultimate streaming and async
214 cleverness). If you want to return a PSGI sub you have to wrap it into an
217 sub dispatch_request {
220 # This is pure PSGI here, so read perldoc PSGI
224 If you return a subroutine with a prototype, the prototype is treated
225 as a match specification - and if the test is passed, the body of the
226 sub is called as a method and passed any matched arguments (see below for more details).
228 You can also return a plain subroutine which will be called with just C<$env>
229 - remember that in this case if you need C<$self> you B<must> close over it.
231 If you return a normal object, L<Web::Simple> will simply return it upwards on
232 the assumption that a response_filter (or some arbitrary L<Plack::Middleware>)
233 somewhere will convert it to something useful. This allows:
235 sub dispatch_request {
237 sub (.html) { response_filter { $self->render_zoom($_[0]) } },
238 sub (/user/*) { $self->users->get($_[1]) },
241 An alternative to using prototypes to declare a match specification for a given
242 route is to provide a Dancer like key-value list:
244 sub dispatch_request {
247 '.html' => sub { response_filter { $self->render_zoom($_[0]) } },
248 '/user/*' => sub { $self->users->get($_[1]) }<
252 This can be useful in situations where you are generating a dispatch table
253 programmatically, where setting a subroutines protoype is difficult.
255 to render a user object to HTML, if there is an incoming URL such as:
257 http://myweb.org/user/111.html
259 This works because as we descend down the dispachers, we first match
260 C<sub (.html)>, which adds a C<response_filter> (basically a specialized routine
261 that follows the L<Plack::Middleware> specification), and then later we also
262 match C<sub (/user/*)> which gets a user and returns that as the response.
263 This user object 'bubbles up' through all the wrapping middleware until it hits
264 the C<response_filter> we defined, after which the return is converted to a
267 However, two types of objects are treated specially - a C<Plack::Component> object
268 will have its C<to_app> method called and be used as a dispatcher:
270 sub dispatch_request {
272 sub (/static/...) { Plack::App::File->new(...) },
276 A L<Plack::Middleware> object will be used as a filter for the rest of the
277 dispatch being returned into:
279 ## responds to /admin/track_usage AND /admin/delete_accounts
281 sub dispatch_request {
284 Plack::Middleware::Session->new(%opts);
286 sub (/admin/track_usage) {
287 ## something that needs a session
289 sub (/admin/delete_accounts) {
290 ## something else that needs a session
294 Note that this is for the dispatch being B<returned> to, so if you want to
295 provide it inline you need to do:
297 ## ALSO responds to /admin/track_usage AND /admin/delete_accounts
299 sub dispatch_request {
303 Plack::Middleware::Session->new(%opts);
306 ## something that needs a session
308 sub (/delete_accounts) {
309 ## something else that needs a session
314 And that's it - but remember that all this happens recursively - it's
315 dispatchers all the way down. A URL incoming pattern will run all matching
316 dispatchers and then hit all added filters or L<Plack::Middleware>.
318 =head2 Web::Simple match specifications
320 =head3 Method matches
324 A match specification beginning with a capital letter matches HTTP requests
325 with that request method.
331 A match specification beginning with a / is a path match. In the simplest
332 case it matches a specific path. To match a path with a wildcard part, you
336 $self->handle_user($_[1])
338 This will match /user/<anything> where <anything> does not include a literal
339 / character. The matched part becomes part of the match arguments. You can
340 also match more than one part:
343 my ($self, $user_1, $user_2) = @_;
345 sub (/domain/*/user/*) {
346 my ($self, $domain, $user) = @_;
348 and so on. To match an arbitrary number of parts, use C<**>:
351 my ($self, $match) = @_;
353 This will result in a single element for the entire match. Note that you can do
355 sub (/page/**/edit) {
357 to match an arbitrary number of parts up to but not including some final
360 Note: Since Web::Simple handles a concept of file extensions, C<*> and C<**>
361 matchers will not by default match things after a final dot, and this
362 can be modified by using C<*.*> and C<**.*> in the final position, e.g.:
364 /one/* matches /one/two.three and captures "two"
365 /one/*.* matches /one/two.three and captures "two.three"
366 /** matches /one/two.three and captures "one/two"
367 /**.* matches /one/two.three and captures "one/two.three"
373 Will match C</foo/> on the beginning of the path B<and> strip it. This is
374 designed to be used to construct nested dispatch structures, but can also prove
375 useful for having e.g. an optional language specification at the start of a
378 Note that the '...' is a "maybe something here, maybe not" so the above
379 specification will match like this:
382 /foo/ # match and strip path to '/'
383 /foo/bar/baz # match and strip path to '/bar/baz'
389 Will match on C</foo/bar/baz>, but also include C</foo>. Otherwise it
390 operates the same way as C</foo/...>.
392 /foo # match and strip path to ''
393 /foo/ # match and strip path to '/'
394 /foo/bar/baz # match and strip path to '/bar/baz'
396 Please note the difference between C<sub(/foo/...)> and C<sub(/foo...)>. In
397 the first case, this is expecting to find something after C</foo> (and fails to
398 match if nothing is found), while in the second case we can match both C</foo>
399 and C</foo/more/to/come>. The following are roughly the same:
401 sub (/foo) { 'I match /foo' },
403 sub (/bar) { 'I match /foo/bar' },
404 sub (/*) { 'I match /foo/{id}' },
410 sub (~) { 'I match /foo' },
411 sub (/bar) { 'I match /foo/bar' },
412 sub (/*) { 'I match /foo/{id}' },
415 You may prefer the latter example should you wish to take advantage of
416 subdispatchers to scope common activities. For example:
419 my $user_rs = $schema->resultset('User');
420 sub (~) { $user_rs },
421 sub (/*) { $user_rs->find($_[1]) },
424 You should note the special case path match C<sub (~)> which is only meaningful
425 when it is contained in this type of path match. It matches to an empty path.
427 =head4 Naming your patch matches
429 Any C<*>, C<**>, C<*.*>, or C<**.*> match can be followed with C<:name> to make it into a named
432 sub (/*:one/*:two/*:three/*:four) {
433 "I match /1/2/3/4 capturing { one => 1, two => 2, three => 3, four => 4 }"
436 sub (/**.*:allofit) {
437 "I match anything capturing { allofit => \$whole_path }"
440 In the specific case of a simple single-* match, the * may be omitted, to
443 sub (/:one/:two/:three/:four) {
444 "I match /1/2/3/4 capturing { one => 1, two => 2, three => 3, four => 4 }"
447 =head4 C</foo> and C</foo/> are different specs
449 As you may have noticed with the difference between C<sub(/foo/...)> and
450 C<sub(/foo...)>, trailing slashes in path specs are significant. This is
451 intentional and necessary to retain the ability to use relative links on
452 websites. Let's demonstrate on this link:
454 <a href="bar">bar</a>
456 If the user loads the url C</foo/> and clicks on this link, they will be
457 sent to C</foo/bar>. However when they are on the url C</foo> and click this
458 link, then they will be sent to C</bar>.
460 This makes it necessary to be explicit about the trailing slash.
462 =head3 Extension matches
466 will match .html from the path (assuming the subroutine itself returns
467 something, of course). This is normally used for rendering - e.g.:
470 response_filter { $self->render_html($_[1]) }
477 will match any extension and supplies the extension as a match argument.
479 =head3 Query and body parameter matches
481 Query and body parameters can be match via
483 sub (?<param spec>) { # match URI query
484 sub (%<param spec>) { # match body params
486 The body spec will match if the request content is either
487 application/x-www-form-urlencoded or multipart/form-data - the latter
488 of which is required for uploads - see below.
490 The param spec is elements of one of the following forms:
492 param~ # optional parameter
493 param= # required parameter
494 @param~ # optional multiple parameter
495 @param= # required multiple parameter
496 :param~ # optional parameter in hashref
497 :param= # required parameter in hashref
498 :@param~ # optional multiple in hashref
499 :@param= # required multiple in hashref
500 * # include all other parameters in hashref
501 @* # include all other parameters as multiple in hashref
503 separated by the C<&> character. The arguments added to the request are
504 one per non-C<:>/C<*> parameter (scalar for normal, arrayref for multiple),
505 plus if any C<:>/C<*> specs exist a hashref containing those values.
507 Please note that if you specify a multiple type parameter match, you are
508 ensured of getting an arrayref for the value, EVEN if the current incoming
509 request has only one value. However if a parameter is specified as single
510 and multiple values are found, the last one will be used.
512 For example to match a C<page> parameter with an optional C<order_by> parameter one
515 sub (?page=&order_by~) {
516 my ($self, $page, $order_by) = @_;
517 return unless $page =~ /^\d+$/;
520 $_[1]->search_rs({}, $p);
524 to implement paging and ordering against a L<DBIx::Class::ResultSet> object.
526 Another Example: To get all parameters as a hashref of arrayrefs, write:
529 my ($self, $params) = @_;
532 To get two parameters as a hashref, write:
534 sub(?:user~&:domain~) {
535 my ($self, $params) = @_; # params contains only 'user' and 'domain' keys
537 You can also mix these, so:
539 sub (?foo=&@bar~&:coffee=&@*) {
540 my ($self, $foo, $bar, $params);
542 where $bar is an arrayref (possibly an empty one), and $params contains
543 arrayref values for all parameters B<not> mentioned and a scalar value for
544 the 'coffee' parameter.
546 Note, in the case where you combine arrayref, single parameter and named
547 hashref style, the arrayref and single parameters will appear in C<@_> in the
548 order you defined them in the protoype, but all hashrefs will merge into a
549 single C<$params>, as in the example above.
551 =head3 Upload matches
553 sub (*foo=) { # param specifier can be anything valid for query or body
555 The upload match system functions exactly like a query/body match, except
556 that the values returned (if any) are C<Web::Dispatch::Upload> objects.
558 Note that this match type will succeed in two circumstances where you might
559 not expect it to - first, when the field exists but is not an upload field
560 and second, when the field exists but the form is not an upload form (i.e.
561 content type "application/x-www-form-urlencoded" rather than
562 "multipart/form-data"). In either of these cases, what you'll get back is
563 a C<Web::Dispatch::NotAnUpload> object, which will C<die> with an error
564 pointing out the problem if you try and use it. To be sure you have a real
567 $upload->is_upload # returns 1 on a valid upload, 0 on a non-upload field
569 and to get the reason why such an object is not an upload, call
571 $upload->reason # returns a reason or '' on a valid upload.
573 Other than these two methods, the upload object provides the same interface
574 as L<Plack::Request::Upload> with the addition of a stringify to the temporary
575 filename to make copying it somewhere else easier to handle.
577 =head3 Combining matches
579 Matches may be combined with the + character - e.g.
581 sub (GET + /user/*) {
583 to create an AND match. They may also be combined withe the | character - e.g.
587 to create an OR match. Matches can be nested with () - e.g.
589 sub ((GET|POST) + /user/*) {
591 and negated with ! - e.g.
593 sub (!/user/foo + /user/*) {
595 ! binds to the immediate rightmost match specification, so if you want
596 to negate a combination you will need to use
598 sub ( !(POST|PUT|DELETE) ) {
600 and | binds tighter than +, so
602 sub ((GET|POST) + /user/*) {
606 sub (GET|POST + /user/*) {
610 sub ((GET + /admin/...) | (POST + /admin/...)) {
614 sub (GET + /admin/... | POST + /admin/...) {
616 are not - the latter is equivalent to
618 sub (GET + (/admin/...|POST) + /admin/...) {
620 which will never match!
624 Note that for legibility you are permitted to use whitespace:
626 sub (GET + /user/*) {
628 but it will be ignored. This is because the perl parser strips whitespace
629 from subroutine prototypes, so this is equivalent to
633 =head3 Accessing parameters via C<%_>
635 If your dispatch specification causes your dispatch subroutine to receive
636 a hash reference as its first argument, the contained named parameters
637 will be accessible via C<%_>.
639 This can be used to access your path matches, if they are named:
641 sub (GET + /foo/:path_part) {
643 ['Content-type' => 'text/plain'],
644 ["We are in $_{path_part}"],
648 Or, if your first argument would be a hash reference containing named
651 sub (GET + /foo + ?:some_param=) {
653 ['Content-type' => 'text/plain'],
654 ["We received $_{some_param} as parameter"],
658 Of course this also works when all you are doing is slurping the whole set
659 of parameters by their name:
661 sub (GET + /foo + ?*) {
663 ['Content-type' => 'text/plain'],
664 [exists($_{foo}) ? "Received a foo: $_{foo}" : "No foo!"],
668 Note that only the first hash reference will be available via C<%_>. If
669 you receive additional hash references, you will need to access them as
672 =head3 Accessing the PSGI env hash
674 In some cases you may wish to get the raw PSGI env hash - to do this,
675 you can either use a plain sub:
682 or use the C<PSGI_ENV> constant exported to retrieve it from C<@_>:
684 sub (GET + /foo + ?some_param=) {
686 my $env = $_[PSGI_ENV];
689 but note that if you're trying to add a middleware, you should simply use
690 Web::Simple's direct support for doing so.
692 =head1 EXPORTED SUBROUTINES
694 =head2 response_filter
697 # Hide errors from the user because we hates them, preciousss
698 if (ref($_[0]) eq 'ARRAY' && $_[0]->[0] == 500) {
699 $_[0] = [ 200, @{$_[0]}[1..$#{$_[0]}] ];
704 The response_filter subroutine is designed for use inside dispatch subroutines.
706 It creates and returns a special dispatcher that always matches, and calls
707 the block passed to it as a filter on the result of running the rest of the
708 current dispatch chain.
710 Thus the filter above runs further dispatch as normal, but if the result of
711 dispatch is a 500 (Internal Server Error) response, changes this to a 200 (OK)
712 response without altering the headers or body.
716 redispatch_to '/other/url';
718 The redispatch_to subroutine is designed for use inside dispatch subroutines.
720 It creates and returns a special dispatcher that always matches, and instead
721 of continuing dispatch re-delegates it to the start of the dispatch process,
722 but with the path of the request altered to the supplied URL.
724 Thus if you receive a POST to C</some/url> and return a redispatch to
725 C</other/url>, the dispatch behaviour will be exactly as if the same POST
726 request had been made to C</other/url> instead.
728 Note, this is not the same as returning an HTTP 3xx redirect as a response;
729 rather it is a much more efficient internal process.
731 =head1 CHANGES BETWEEN RELEASES
733 =head2 Changes between 0.004 and 0.005
737 =item * dispatch {} replaced by declaring a dispatch_request method
739 dispatch {} has gone away - instead, you write:
741 sub dispatch_request {
743 sub (GET /foo/) { ... },
747 Note that this method is still B<returning> the dispatch code - just like
750 Also note that you need the C<< my $self = shift >> since the magic $self
753 =item * the magic $self variable went away.
755 Just add C<< my $self = shift; >> while writing your C<< sub dispatch_request { >>
756 like a normal perl method.
758 =item * subdispatch deleted - all dispatchers can now subdispatch
760 In earlier releases you needed to write:
762 subdispatch sub (/foo/...) {
765 sub (GET /bar/) { ... },
770 As of 0.005, you can instead write simply:
775 sub (GET /bar/) { ... },
782 =head2 Changes since Antiquated Perl
786 =item * filter_response renamed to response_filter
788 This is a pure rename; a global search and replace should fix it.
790 =item * dispatch [] changed to dispatch {}
794 dispatch [ sub(...) { ... }, ... ];
798 dispatch { sub(...) { ... }, ... };
804 =head1 DEVELOPMENT HISTORY
806 Web::Simple was originally written to form part of my Antiquated Perl talk for
807 Italian Perl Workshop 2009, but in writing the bloggery example I realised
808 that having a bare minimum system for writing web applications that doesn't
809 drive me insane was rather nice and decided to spend my attempt at nanowrimo
810 for 2009 improving and documenting it to the point where others could use it.
812 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
813 L<Web::Simple::AntiquatedPerl>.
815 =head1 COMMUNITY AND SUPPORT
819 irc.perl.org #web-simple
821 =head2 No mailing list yet
823 Because mst's non-work email is a bombsite so he'd never read it anyway.
825 =head2 Git repository
827 Gitweb is on http://git.shadowcat.co.uk/ and the clone URL is:
829 git clone git://git.shadowcat.co.uk/catagits/Web-Simple.git
833 Matt S. Trout (mst) <mst@shadowcat.co.uk>
837 Devin Austin (dhoss) <dhoss@cpan.org>
839 Arthur Axel 'fREW' Schmidt <frioux@gmail.com>
841 gregor herrmann (gregoa) <gregoa@debian.org>
843 John Napiorkowski (jnap) <jjn1056@yahoo.com>
845 Josh McMichael <jmcmicha@linus222.gsc.wustl.edu>
847 Justin Hunter (arcanez) <justin.d.hunter@gmail.com>
849 Kjetil Kjernsmo <kjetil@kjernsmo.net>
851 markie <markie@nulletch64.dreamhost.com>
853 Christian Walde (Mithaldu) <walde.christian@googlemail.com>
855 nperez <nperez@cpan.org>
857 Robin Edwards <robin.ge@gmail.com>
859 Andrew Rodland (hobbs) <andrew@cleverdomain.org>
861 Robert Sedlacek (phaylon) <r.sedlacek@shadowcat.co.uk>
865 Copyright (c) 2011 the Web::Simple L</AUTHOR> and L</CONTRIBUTORS>
870 This library is free software and may be distributed under the same terms