4 use warnings FATAL => 'all';
7 our $VERSION = '0.001';
9 sub setup_all_strictures {
11 warnings->import(FATAL => 'all');
14 sub setup_dispatch_strictures {
15 setup_all_strictures();
16 warnings->unimport('syntax');
17 warnings->import(FATAL => qw(
18 ambiguous bareword digit parenthesis precedence printf
19 prototype qw reserved semicolon
24 setup_dispatch_strictures();
25 my ($class, $app_package) = @_;
26 $class->_export_into($app_package);
30 my ($class, $app_package) = @_;
33 *{"${app_package}::dispatch"} = sub (&) {
34 $app_package->_setup_dispatcher([ $_[0]->() ]);
36 *{"${app_package}::response_filter"} = sub (&) {
37 $app_package->_construct_response_filter($_[0]);
39 *{"${app_package}::redispatch_to"} = sub {
40 $app_package->_construct_redispatch($_[0]);
42 *{"${app_package}::subdispatch"} = sub ($) {
43 $app_package->_construct_subdispatch($_[0]);
45 *{"${app_package}::default_config"} = sub {
46 $app_package->_setup_default_config(@_);
48 *{"${app_package}::self"} = \${"${app_package}::self"};
49 require Web::Simple::Application;
50 unshift(@{"${app_package}::ISA"}, 'Web::Simple::Application');
52 (my $name = $app_package) =~ s/::/\//g;
53 $INC{"${name}.pm"} = 'Set by "use Web::Simple;" invocation';
58 Web::Simple - A quick and easy way to build simple web applications
62 This is really quite new. If you're reading this on CPAN, it means the stuff
63 that's here we're probably happy with. But only probably. So we may have to
64 change stuff. And if you're reading this from git, come check with irc.perl.org
65 #web-simple that we're actually sure we're going to keep anything that's
66 different from the CPAN version.
68 If we do find we have to change stuff we'll add to the
69 L<CHANGES BETWEEN RELEASES> section explaining how to switch your code across
70 to the new version, and we'll do our best to make it as painless as possible
71 because we've got Web::Simple applications too. But we can't promise not to
72 change things at all. Not yet. Sorry.
78 use Web::Simple 'HelloWorld';
85 [ 200, [ 'Content-type', 'text/plain' ], [ 'Hello world!' ] ]
88 [ 405, [ 'Content-type', 'text/plain' ], [ 'Method not allowed' ] ]
93 HelloWorld->run_if_script;
95 If you save this file into your cgi-bin as hello-world.cgi and then visit
97 http://my.server.name/cgi-bin/hello-world.cgi/
99 you'll get the "Hello world!" string output to your browser. For more complex
100 examples and non-CGI deployment, see below. To get help with Web::Simple,
101 please connect to the irc.perl.org IRC network and join #web-simple.
105 Web::Simple was originally written to form part of my Antiquated Perl talk for
106 Italian Perl Workshop 2009, but in writing the bloggery example I realised
107 that having a bare minimum system for writing web applications that doesn't
108 drive me insane was rather nice and decided to spend my attempt at nanowrimo
109 for 2009 improving and documenting it to the point where others could use it.
111 The philosophy of Web::Simple is to keep to an absolute bare minimum, for
112 everything. It is not designed to be used for large scale applications;
113 the L<Catalyst> web framework already works very nicely for that and is
114 a far more mature, well supported piece of software.
116 However, if you have an application that only does a couple of things, and
117 want to not have to think about complexities of deployment, then Web::Simple
118 might be just the thing for you.
120 The Antiquated Perl talk can be found at L<http://www.shadowcat.co.uk/archive/conference-video/>.
124 The only public interface the Web::Simple module itself provides is an
127 use Web::Simple 'NameOfApplication';
129 This imports 'strict' and 'warnings FATAL => "all"' into your code as well,
130 so you can skip the usual
135 provided you 'use Web::Simple' at the top of the file. Note that we turn
136 on *fatal* warnings so if you have any warnings at any point from the file
137 that you did 'use Web::Simple' in, then your application will die. This is,
138 so far, considered a feature.
140 Calling the import also makes NameOfApplication isa Web::Simple::Application
141 - i.e. does the equivalent of
144 package NameOfApplication;
145 use base qw(Web::Simple::Application);
148 It also exports the following subroutines:
155 dispatch { sub (...) { ... }, ... };
157 response_filter { ... };
159 redispatch_to '/somewhere';
161 subdispatch sub (...) { ... }
163 and creates a $self global variable in your application package, so you can
164 use $self in dispatch subs without violating strict (Web::Simple::Application
165 arranges for dispatch subroutines to have the correct $self in scope when
170 $INC{"NameOfApplication.pm"} = 'Set by "use Web::Simple;" invocation';
172 so that perl will not attempt to load the application again even if
174 require NameOfApplication;
176 is encountered in other code.
178 =head1 EXPORTED SUBROUTINES
180 =head2 default_config
184 another_key => 'bar',
189 $self->config->{one_key} # 'foo'
191 This creates the default configuration for the application, by creating a
193 sub _default_config {
194 return (one_key => 'foo', another_key => 'bar');
197 in the application namespace when executed. Note that this means that
198 you should only run default_config once - calling it a second time will
199 cause an exception to be thrown.
205 [ 200, [ 'Content-type', 'text/plain' ], [ 'Hello world!' ] ]
208 [ 405, [ 'Content-type', 'text/plain' ], [ 'Method not allowed' ] ]
212 The dispatch subroutine calls NameOfApplication->_setup_dispatcher with
213 the return value of the block passed to it, which then creates your Web::Simple
214 application's dispatcher from these subs. The prototype of each subroutine
215 is expected to be a Web::Simple dispatch specification (see
216 L</DISPATCH SPECIFICATIONS> below for more details), and the body of the
217 subroutine is the code to execute if the specification matches.
219 Each dispatcher is given the dispatcher constructed from the next subroutine
220 returned as its next dispatcher, except for the final subroutine, which
221 is given the return value of NameOfApplication->_build_final_dispatcher
222 as its next dispatcher (by default this returns a 500 error response).
224 See L</DISPATCH STRATEGY> below for details on how the Web::Simple dispatch
225 system uses the return values of these subroutines to determine how to
226 continue, alter or abort dispatch.
228 Note that _setup_dispatcher creates a
231 return <root dispatcher object here>;
234 method in your class so as with default_config, calling dispatch a second time
235 will result in an exception.
237 =head2 response_filter
240 # Hide errors from the user because we hates them, preciousss
241 if (ref($_[1]) eq 'ARRAY' && $_[1]->[0] == 500) {
242 $_[1] = [ 200, @{$_[1]}[1..$#{$_[1]}] ];
247 The response_filter subroutine is designed for use inside dispatch subroutines.
249 It creates and returns a special dispatcher that always matches, and calls
250 the block passed to it as a filter on the result of running the rest of the
251 current dispatch chain.
253 Thus the filter above runs further dispatch as normal, but if the result of
254 dispatch is a 500 (Internal Server Error) response, changes this to a 200 (OK)
255 response without altering the headers or body.
259 redispatch_to '/other/url';
261 The redispatch_to subroutine is designed for use inside dispatch subroutines.
263 It creates and returns a special dispatcher that always matches, and instead
264 of continuing dispatch re-delegates it to the start of the dispatch process,
265 but with the path of the request altered to the supplied URL.
267 Thus if you receive a POST to '/some/url' and return a redipstch to
268 '/other/url', the dispatch behaviour will be exactly as if the same POST
269 request had been made to '/other/url' instead.
273 subdispatch sub (/user/*/) {
274 my $u = $self->user($_[1]);
277 sub (DELETE) { $u->delete },
281 The subdispatch subroutine is designed for use in dispatcher construction.
283 It creates a dispatcher which, if it matches, treats its return value not
284 as a final value but an arrayref of dispatch specifications such as could
285 be passed to the dispatch subroutine itself. These are turned into a dispatcher
286 which is then invoked. Any changes the match makes to the request are in
287 scope for this inner dispatcher only - so if the initial match is a
288 destructive one like .html the full path will be restored if the
291 =head1 DISPATCH STRATEGY
293 =head2 Description of the dispatcher object
295 Web::Simple::Dispatcher objects have three components:
299 =item * match - an optional test if this dispatcher matches the request
301 =item * call - a routine to call if this dispatcher matches (or has no match)
303 =item * next - the next dispatcher to call
307 When a dispatcher is invoked, it checks its match routine against the
308 request environment. The match routine may provide alterations to the
309 request as a result of matching, and/or arguments for the call routine.
311 If no match routine has been provided then Web::Simple treats this as
312 a success, and supplies the request environment to the call routine as
315 Given a successful match, the call routine is now invoked in list context
316 with any arguments given to the original dispatch, plus any arguments
317 provided by the match result.
319 If this routine returns (), Web::Simple treats this identically to a failure
322 If this routine returns a Web::Simple::Dispatcher, the environment changes
323 are merged into the environment and the new dispatcher's next pointer is
324 set to our next pointer.
326 If this routine returns anything else, that is treated as the end of dispatch
327 and the value is returned.
329 On a failed match, Web::Simple invokes the next dispatcher with the same
330 arguments and request environment passed to the current one. On a successful
331 match that returned a new dispatcher, Web::Simple invokes the new dispatcher
332 with the same arguments but the modified request environment.
334 =head2 How Web::Simple builds dispatcher objects for you
336 In the case of the Web::Simple L</dispatch> export the match is constructed
337 from the subroutine prototype - i.e.
339 sub (<match specification>) {
343 and the 'next' pointer is populated with the next element of the array,
344 expect for the last element, which is given a next that will throw a 500
345 error if none of your dispatchers match. If you want to provide something
346 else as a default, a routine with no match specification always matches, so -
349 [ 404, [ 'Content-type', 'text/plain' ], [ 'Error: Not Found' ] ]
352 will produce a 404 result instead of a 500 by default. You can also override
353 the L<Web::Simple::Application/_build_final_dispatcher> method in your app.
355 Note that the code in the subroutine is executed as a -method- on your
356 application object, so if your match specification provides arguments you
357 should unpack them like so:
359 sub (<match specification>) {
360 my ($self, @args) = @_;
364 =head2 Web::Simple match specifications
366 =head3 Method matches
370 A match specification beginning with a capital letter matches HTTP requests
371 with that request method.
377 A match specification beginning with a / is a path match. In the simplest
378 case it matches a specific path. To match a path with a wildcard part, you
382 $self->handle_user($_[1])
384 This will match /user/<anything> where <anything> does not include a literal
385 / character. The matched part becomes part of the match arguments. You can
386 also match more than one part:
389 my ($self, $user_1, $user_2) = @_;
391 sub (/domain/*/user/*) {
392 my ($self, $domain, $user) = @_;
394 and so on. To match an arbitrary number of parts, use -
398 This will result in an element per /-separated part so matched. Note that
401 sub (/page/**/edit) {
403 to match an arbitrary number of parts up to but not including some final
410 will match /foo/ on the beginning of the path -and- strip it, much like
411 .html strips the extension. This is designed to be used to construct
412 nested dispatch structures, but can also prove useful for having e.g. an
413 optional language specification at the start of a path.
415 Note that the '...' is a "maybe something here, maybe not" so the above
416 specification will match like this:
419 /foo/ # match and strip path to '/'
420 /foo/bar/baz # match and strip path to '/bar/baz'
422 =head3 Extension matches
426 will match and strip .html from the path (assuming the subroutine itself
427 returns something, of course). This is normally used for rendering - e.g.
430 response_filter { $self->render_html($_[1]) }
437 will match any extension and supplies the stripped extension as a match
440 =head3 Query and body parameter matches
442 Query and body parameters can be match via
444 sub (?<param spec>) { # match URI query
445 sub (%<param spec>) { # match body params
447 The body is only matched if the content type is
448 application/x-www-form-urlencoded (note this means that Web::Simple does
449 not yet handle uploads; this will be addressed in a later release).
451 The param spec is elements of one of the following forms -
453 param~ # optional parameter
454 param= # required parameter
455 @param~ # optional multiple parameter
456 @param= # required multiple parameter
457 :param~ # optional parameter in hashref
458 :param= # required parameter in hashref
459 :@param~ # optional multiple in hashref
460 :@param= # required multiple in hashref
461 * # include all other parameters in hashref
462 @* # include all other parameters as multiple in hashref
464 separated by the & character. The arguments added to the request are
465 one per non-:/* parameter (scalar for normal, arrayref for multiple),
466 plus if any :/* specs exist a hashref containing those values.
468 So, to match a page parameter with an optional order_by parameter one
471 sub (?page=&order_by~) {
472 my ($self, $page, $order_by) = @_;
473 return unless $page =~ /^\d+$/;
476 $_[1]->search_rs({}, $p);
480 to implement paging and ordering against a L<DBIx::Class::ResultSet> object.
482 Note that if a parameter is specified as single and multiple values are found,
483 the last one will be used.
485 To get all parameters as a hashref of arrayrefs, write:
488 my ($self, $params) = @_;
491 To get two parameters as a hashref, write:
493 sub(?:user~&:domain~) {
494 my ($self, $params) = @_; # params contains only 'user' and 'domain' keys
496 You can also mix these, so:
498 sub (?foo=&@bar~&:coffee=&@*) {
499 my ($self, $foo, $bar, $params);
501 where $bar is an arrayref (possibly an empty one), and $params contains
502 arrayref values for all parameters -not- mentioned and a scalar value for
503 the 'coffee' parameter.
505 =head3 Combining matches
507 Matches may be combined with the + character - e.g.
509 sub (GET + /user/*) {
511 to create an AND match. They may also be combined withe the | character - e.g.
515 to create an OR match. Matches can be nested with () - e.g.
517 sub ((GET|POST) + /user/*) {
519 and negated with ! - e.g.
521 sub (!/user/foo + /user/*) {
523 ! binds to the immediate rightmost match specification, so if you want
524 to negate a combination you will need to use
526 sub ( !(POST|PUT|DELETE) ) {
528 and | binds tighter than +, so
530 sub ((GET|POST) + /user/*) {
534 sub (GET|POST + /user/*) {
538 sub ((GET + .html) | (POST + .html)) {
542 sub (GET + .html | POST + .html) {
544 are not - the latter is equivalent to
546 sub (GET + (.html|POST) + .html) {
548 which will never match.
552 Note that for legibility you are permitted to use whitespace -
554 sub (GET + /user/*) {
556 but it will be ignored. This is because the perl parser strips whitespace
557 from subroutine prototypes, so this is equivalent to
561 =head1 CHANGES BETWEEN RELEASES
563 =head2 Changes since Antiquated Perl
567 =item * filter_response renamed to response_filter
569 This is a pure rename; a global search and replace should fix it.
571 =item * dispatch [] changed to dispatch []
575 dispatch [ sub(...) { ... }, ... ];
579 dispatch { sub(...) { ... }, ... };
585 =head1 COMMUNITY AND SUPPORT
589 irc.perl.org #web-simple
591 =head2 No mailing list yet
593 Because mst's non-work email is a bombsite so he'd never read it anyway.
595 =head2 Git repository
597 Gitweb is on http://git.shadowcat.co.uk/ and the clone URL is:
599 git clone git://git.shadowcat.co.uk/catagits/Web-Simple.git
603 Matt S. Trout <mst@shadowcat.co.uk>
607 None required yet. Maybe this module is perfect (hahahahaha ...).
611 Copyright (c) 2009 the Web::Simple L</AUTHOR> and L</CONTRIBUTORS>
616 This library is free software and may be distributed under the same terms