5 use warnings::illegalproto ();
7 use Web::Dispatch::Wrapper ();
9 our $VERSION = '0.026';
12 my ($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]) },
249 'POST + %*' => 'handle_post',
253 This can be useful in situations where you are generating a dispatch table
254 programmatically, where setting a subroutines protoype is difficult. Note that
255 in the example above, C<handle_post> is a method that would be called.
257 to render a user object to HTML, if there is an incoming URL such as:
259 http://myweb.org/user/111.html
261 This works because as we descend down the dispachers, we first match
262 C<sub (.html)>, which adds a C<response_filter> (basically a specialized routine
263 that follows the L<Plack::Middleware> specification), and then later we also
264 match C<sub (/user/*)> which gets a user and returns that as the response.
265 This user object 'bubbles up' through all the wrapping middleware until it hits
266 the C<response_filter> we defined, after which the return is converted to a
269 However, two types of objects are treated specially - a C<Plack::Component> object
270 will have its C<to_app> method called and be used as a dispatcher:
272 sub dispatch_request {
274 sub (/static/...) { Plack::App::File->new(...) },
278 A L<Plack::Middleware> object will be used as a filter for the rest of the
279 dispatch being returned into:
281 ## responds to /admin/track_usage AND /admin/delete_accounts
283 sub dispatch_request {
286 Plack::Middleware::Session->new(%opts);
288 sub (/admin/track_usage) {
289 ## something that needs a session
291 sub (/admin/delete_accounts) {
292 ## something else that needs a session
296 Note that this is for the dispatch being B<returned> to, so if you want to
297 provide it inline you need to do:
299 ## ALSO responds to /admin/track_usage AND /admin/delete_accounts
301 sub dispatch_request {
305 Plack::Middleware::Session->new(%opts);
308 ## something that needs a session
310 sub (/delete_accounts) {
311 ## something else that needs a session
316 And that's it - but remember that all this happens recursively - it's
317 dispatchers all the way down. A URL incoming pattern will run all matching
318 dispatchers and then hit all added filters or L<Plack::Middleware>.
320 =head2 Web::Simple match specifications
322 =head3 Method matches
326 A match specification beginning with a capital letter matches HTTP requests
327 with that request method.
333 A match specification beginning with a / is a path match. In the simplest
334 case it matches a specific path. To match a path with a wildcard part, you
338 $self->handle_user($_[1])
340 This will match /user/<anything> where <anything> does not include a literal
341 / character. The matched part becomes part of the match arguments. You can
342 also match more than one part:
345 my ($self, $user_1, $user_2) = @_;
347 sub (/domain/*/user/*) {
348 my ($self, $domain, $user) = @_;
350 and so on. To match an arbitrary number of parts, use C<**>:
353 my ($self, $match) = @_;
355 This will result in a single element for the entire match. Note that you can do
357 sub (/page/**/edit) {
359 to match an arbitrary number of parts up to but not including some final
362 Note: Since Web::Simple handles a concept of file extensions, C<*> and C<**>
363 matchers will not by default match things after a final dot, and this
364 can be modified by using C<*.*> and C<**.*> in the final position, e.g.:
366 /one/* matches /one/two.three and captures "two"
367 /one/*.* matches /one/two.three and captures "two.three"
368 /** matches /one/two.three and captures "one/two"
369 /**.* matches /one/two.three and captures "one/two.three"
375 Will match C</foo/> on the beginning of the path B<and> strip it. This is
376 designed to be used to construct nested dispatch structures, but can also prove
377 useful for having e.g. an optional language specification at the start of a
380 Note that the '...' is a "maybe something here, maybe not" so the above
381 specification will match like this:
384 /foo/ # match and strip path to '/'
385 /foo/bar/baz # match and strip path to '/bar/baz'
391 Will match on C</foo/bar/baz>, but also include C</foo>. Otherwise it
392 operates the same way as C</foo/...>.
394 /foo # match and strip path to ''
395 /foo/ # match and strip path to '/'
396 /foo/bar/baz # match and strip path to '/bar/baz'
398 Please note the difference between C<sub(/foo/...)> and C<sub(/foo...)>. In
399 the first case, this is expecting to find something after C</foo> (and fails to
400 match if nothing is found), while in the second case we can match both C</foo>
401 and C</foo/more/to/come>. The following are roughly the same:
403 sub (/foo) { 'I match /foo' },
405 sub (/bar) { 'I match /foo/bar' },
406 sub (/*) { 'I match /foo/{id}' },
412 sub (~) { 'I match /foo' },
413 sub (/bar) { 'I match /foo/bar' },
414 sub (/*) { 'I match /foo/{id}' },
417 You may prefer the latter example should you wish to take advantage of
418 subdispatchers to scope common activities. For example:
421 my $user_rs = $schema->resultset('User');
422 sub (~) { $user_rs },
423 sub (/*) { $user_rs->find($_[1]) },
426 You should note the special case path match C<sub (~)> which is only meaningful
427 when it is contained in this type of path match. It matches to an empty path.
429 =head4 Naming your patch matches
431 Any C<*>, C<**>, C<*.*>, or C<**.*> match can be followed with C<:name> to make it into a named
434 sub (/*:one/*:two/*:three/*:four) {
435 "I match /1/2/3/4 capturing { one => 1, two => 2, three => 3, four => 4 }"
438 sub (/**.*:allofit) {
439 "I match anything capturing { allofit => \$whole_path }"
442 In the specific case of a simple single-* match, the * may be omitted, to
445 sub (/:one/:two/:three/:four) {
446 "I match /1/2/3/4 capturing { one => 1, two => 2, three => 3, four => 4 }"
449 =head4 C</foo> and C</foo/> are different specs
451 As you may have noticed with the difference between C<sub(/foo/...)> and
452 C<sub(/foo...)>, trailing slashes in path specs are significant. This is
453 intentional and necessary to retain the ability to use relative links on
454 websites. Let's demonstrate on this link:
456 <a href="bar">bar</a>
458 If the user loads the url C</foo/> and clicks on this link, they will be
459 sent to C</foo/bar>. However when they are on the url C</foo> and click this
460 link, then they will be sent to C</bar>.
462 This makes it necessary to be explicit about the trailing slash.
464 =head3 Extension matches
468 will match .html from the path (assuming the subroutine itself returns
469 something, of course). This is normally used for rendering - e.g.:
472 response_filter { $self->render_html($_[1]) }
479 will match any extension and supplies the extension as a match argument.
481 =head3 Query and body parameter matches
483 Query and body parameters can be match via
485 sub (?<param spec>) { # match URI query
486 sub (%<param spec>) { # match body params
488 The body spec will match if the request content is either
489 application/x-www-form-urlencoded or multipart/form-data - the latter
490 of which is required for uploads - see below.
492 The param spec is elements of one of the following forms:
494 param~ # optional parameter
495 param= # required parameter
496 @param~ # optional multiple parameter
497 @param= # required multiple parameter
498 :param~ # optional parameter in hashref
499 :param= # required parameter in hashref
500 :@param~ # optional multiple in hashref
501 :@param= # required multiple in hashref
502 * # include all other parameters in hashref
503 @* # include all other parameters as multiple in hashref
505 separated by the C<&> character. The arguments added to the request are
506 one per non-C<:>/C<*> parameter (scalar for normal, arrayref for multiple),
507 plus if any C<:>/C<*> specs exist a hashref containing those values.
509 Please note that if you specify a multiple type parameter match, you are
510 ensured of getting an arrayref for the value, EVEN if the current incoming
511 request has only one value. However if a parameter is specified as single
512 and multiple values are found, the last one will be used.
514 For example to match a C<page> parameter with an optional C<order_by> parameter one
517 sub (?page=&order_by~) {
518 my ($self, $page, $order_by) = @_;
519 return unless $page =~ /^\d+$/;
522 $_[1]->search_rs({}, { page => $page, order_by => $order_by });
526 to implement paging and ordering against a L<DBIx::Class::ResultSet> object.
528 Another Example: To get all parameters as a hashref of arrayrefs, write:
531 my ($self, $params) = @_;
534 To get two parameters as a hashref, write:
536 sub(?:user~&:domain~) {
537 my ($self, $params) = @_; # params contains only 'user' and 'domain' keys
539 You can also mix these, so:
541 sub (?foo=&@bar~&:coffee=&@*) {
542 my ($self, $foo, $bar, $params);
544 where $bar is an arrayref (possibly an empty one), and $params contains
545 arrayref values for all parameters B<not> mentioned and a scalar value for
546 the 'coffee' parameter.
548 Note, in the case where you combine arrayref, single parameter and named
549 hashref style, the arrayref and single parameters will appear in C<@_> in the
550 order you defined them in the protoype, but all hashrefs will merge into a
551 single C<$params>, as in the example above.
553 =head3 Upload matches
555 sub (*foo=) { # param specifier can be anything valid for query or body
557 The upload match system functions exactly like a query/body match, except
558 that the values returned (if any) are C<Web::Dispatch::Upload> objects.
560 Note that this match type will succeed in two circumstances where you might
561 not expect it to - first, when the field exists but is not an upload field
562 and second, when the field exists but the form is not an upload form (i.e.
563 content type "application/x-www-form-urlencoded" rather than
564 "multipart/form-data"). In either of these cases, what you'll get back is
565 a C<Web::Dispatch::NotAnUpload> object, which will C<die> with an error
566 pointing out the problem if you try and use it. To be sure you have a real
569 $upload->is_upload # returns 1 on a valid upload, 0 on a non-upload field
571 and to get the reason why such an object is not an upload, call
573 $upload->reason # returns a reason or '' on a valid upload.
575 Other than these two methods, the upload object provides the same interface
576 as L<Plack::Request::Upload> with the addition of a stringify to the temporary
577 filename to make copying it somewhere else easier to handle.
579 =head3 Combining matches
581 Matches may be combined with the + character - e.g.
583 sub (GET + /user/*) {
585 to create an AND match. They may also be combined withe the | character - e.g.
589 to create an OR match. Matches can be nested with () - e.g.
591 sub ((GET|POST) + /user/*) {
593 and negated with ! - e.g.
595 sub (!/user/foo + /user/*) {
597 ! binds to the immediate rightmost match specification, so if you want
598 to negate a combination you will need to use
600 sub ( !(POST|PUT|DELETE) ) {
602 and | binds tighter than +, so
604 sub ((GET|POST) + /user/*) {
608 sub (GET|POST + /user/*) {
612 sub ((GET + /admin/...) | (POST + /admin/...)) {
616 sub (GET + /admin/... | POST + /admin/...) {
618 are not - the latter is equivalent to
620 sub (GET + (/admin/...|POST) + /admin/...) {
622 which will never match!
626 Note that for legibility you are permitted to use whitespace:
628 sub (GET + /user/*) {
630 but it will be ignored. This is because the perl parser strips whitespace
631 from subroutine prototypes, so this is equivalent to
635 =head3 Accessing parameters via C<%_>
637 If your dispatch specification causes your dispatch subroutine to receive
638 a hash reference as its first argument, the contained named parameters
639 will be accessible via C<%_>.
641 This can be used to access your path matches, if they are named:
643 sub (GET + /foo/:path_part) {
645 ['Content-type' => 'text/plain'],
646 ["We are in $_{path_part}"],
650 Or, if your first argument would be a hash reference containing named
653 sub (GET + /foo + ?:some_param=) {
655 ['Content-type' => 'text/plain'],
656 ["We received $_{some_param} as parameter"],
660 Of course this also works when all you are doing is slurping the whole set
661 of parameters by their name:
663 sub (GET + /foo + ?*) {
665 ['Content-type' => 'text/plain'],
666 [exists($_{foo}) ? "Received a foo: $_{foo}" : "No foo!"],
670 Note that only the first hash reference will be available via C<%_>. If
671 you receive additional hash references, you will need to access them as
674 =head3 Accessing the PSGI env hash
676 In some cases you may wish to get the raw PSGI env hash - to do this,
677 you can either use a plain sub:
684 or use the C<PSGI_ENV> constant exported to retrieve it from C<@_>:
686 sub (GET + /foo + ?some_param=) {
688 my $env = $_[PSGI_ENV];
691 but note that if you're trying to add a middleware, you should simply use
692 Web::Simple's direct support for doing so.
694 =head1 EXPORTED SUBROUTINES
696 =head2 response_filter
699 # Hide errors from the user because we hates them, preciousss
700 if (ref($_[0]) eq 'ARRAY' && $_[0]->[0] == 500) {
701 $_[0] = [ 200, @{$_[0]}[1..$#{$_[0]}] ];
706 The response_filter subroutine is designed for use inside dispatch subroutines.
708 It creates and returns a special dispatcher that always matches, and calls
709 the block passed to it as a filter on the result of running the rest of the
710 current dispatch chain.
712 Thus the filter above runs further dispatch as normal, but if the result of
713 dispatch is a 500 (Internal Server Error) response, changes this to a 200 (OK)
714 response without altering the headers or body.
718 redispatch_to '/other/url';
720 The redispatch_to subroutine is designed for use inside dispatch subroutines.
722 It creates and returns a special dispatcher that always matches, and instead
723 of continuing dispatch re-delegates it to the start of the dispatch process,
724 but with the path of the request altered to the supplied URL.
726 Thus if you receive a POST to C</some/url> and return a redispatch to
727 C</other/url>, the dispatch behaviour will be exactly as if the same POST
728 request had been made to C</other/url> instead.
730 Note, this is not the same as returning an HTTP 3xx redirect as a response;
731 rather it is a much more efficient internal process.
733 =head1 CHANGES BETWEEN RELEASES
735 =head2 Changes between 0.004 and 0.005
739 =item * dispatch {} replaced by declaring a dispatch_request method
741 dispatch {} has gone away - instead, you write:
743 sub dispatch_request {
745 sub (GET /foo/) { ... },
749 Note that this method is still B<returning> the dispatch code - just like
752 Also note that you need the C<< my $self = shift >> since the magic $self
755 =item * the magic $self variable went away.
757 Just add C<< my $self = shift; >> while writing your C<< sub dispatch_request { >>
758 like a normal perl method.
760 =item * subdispatch deleted - all dispatchers can now subdispatch
762 In earlier releases you needed to write:
764 subdispatch sub (/foo/...) {
767 sub (GET /bar/) { ... },
772 As of 0.005, you can instead write simply:
777 sub (GET /bar/) { ... },
784 =head2 Changes since Antiquated Perl
788 =item * filter_response renamed to response_filter
790 This is a pure rename; a global search and replace should fix it.
792 =item * dispatch [] changed to dispatch {}
796 dispatch [ sub(...) { ... }, ... ];
800 dispatch { sub(...) { ... }, ... };
806 =head1 DEVELOPMENT HISTORY
808 Web::Simple was originally written to form part of my Antiquated Perl talk for
809 Italian Perl Workshop 2009, but in writing the bloggery example I realised
810 that having a bare minimum system for writing web applications that doesn't
811 drive me insane was rather nice and decided to spend my attempt at nanowrimo
812 for 2009 improving and documenting it to the point where others could use it.
814 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
815 L<Web::Simple::AntiquatedPerl>.
817 =head1 COMMUNITY AND SUPPORT
821 irc.perl.org #web-simple
823 =head2 No mailing list yet
825 Because mst's non-work email is a bombsite so he'd never read it anyway.
827 =head2 Git repository
829 Gitweb is on http://git.shadowcat.co.uk/ and the clone URL is:
831 git clone git://git.shadowcat.co.uk/catagits/Web-Simple.git
835 Matt S. Trout (mst) <mst@shadowcat.co.uk>
839 Devin Austin (dhoss) <dhoss@cpan.org>
841 Arthur Axel 'fREW' Schmidt <frioux@gmail.com>
843 gregor herrmann (gregoa) <gregoa@debian.org>
845 John Napiorkowski (jnap) <jjn1056@yahoo.com>
847 Josh McMichael <jmcmicha@linus222.gsc.wustl.edu>
849 Justin Hunter (arcanez) <justin.d.hunter@gmail.com>
851 Kjetil Kjernsmo <kjetil@kjernsmo.net>
853 markie <markie@nulletch64.dreamhost.com>
855 Christian Walde (Mithaldu) <walde.christian@googlemail.com>
857 nperez <nperez@cpan.org>
859 Robin Edwards <robin.ge@gmail.com>
861 Andrew Rodland (hobbs) <andrew@cleverdomain.org>
863 Robert Sedlacek (phaylon) <r.sedlacek@shadowcat.co.uk>
865 Hakim Cassimally (osfameron) <osfameron@cpan.org>
867 Karen Etheridge (ether) <ether@cpan.org>
871 Copyright (c) 2011 the Web::Simple L</AUTHOR> and L</CONTRIBUTORS>
876 This library is free software and may be distributed under the same terms