X-Git-Url: http://git.shadowcat.co.uk/gitweb/gitweb.cgi?a=blobdiff_plain;f=lib%2FWeb%2FSimple.pm;h=a9711fedd0f9e449400650f51759d8eed9594513;hb=bf8b2de8feaede508df35b7741f3a0afe68e5c26;hp=df3f461effba576de6965f0e89a7c7444e70a8d0;hpb=391190822264aefefa6755d410141688a7155dee;p=catagits%2FWeb-Simple.git diff --git a/lib/Web/Simple.pm b/lib/Web/Simple.pm index df3f461..a9711fe 100644 --- a/lib/Web/Simple.pm +++ b/lib/Web/Simple.pm @@ -2,15 +2,26 @@ package Web::Simple; use strict; use warnings FATAL => 'all'; +use 5.008; -sub import { +our $VERSION = '0.002'; + +sub setup_all_strictures { strict->import; warnings->import(FATAL => 'all'); +} + +sub setup_dispatch_strictures { + setup_all_strictures(); warnings->unimport('syntax'); warnings->import(FATAL => qw( ambiguous bareword digit parenthesis precedence printf prototype qw reserved semicolon )); +} + +sub import { + setup_dispatch_strictures(); my ($class, $app_package) = @_; $class->_export_into($app_package); } @@ -19,23 +30,636 @@ sub _export_into { my ($class, $app_package) = @_; { no strict 'refs'; - *{"${app_package}::dispatch"} = sub { - $app_package->_setup_dispatchables(@_); + *{"${app_package}::dispatch"} = sub (&) { + $app_package->_setup_dispatcher([ $_[0]->() ]); }; - *{"${app_package}::filter_response"} = sub (&) { + *{"${app_package}::response_filter"} = sub (&) { $app_package->_construct_response_filter($_[0]); }; *{"${app_package}::redispatch_to"} = sub { $app_package->_construct_redispatch($_[0]); }; + *{"${app_package}::subdispatch"} = sub ($) { + $app_package->_construct_subdispatch($_[0]); + }; *{"${app_package}::default_config"} = sub { - my @defaults = @_; - *{"${app_package}::_default_config"} = sub { @defaults }; + $app_package->_setup_default_config(@_); }; *{"${app_package}::self"} = \${"${app_package}::self"}; require Web::Simple::Application; unshift(@{"${app_package}::ISA"}, 'Web::Simple::Application'); } + (my $name = $app_package) =~ s/::/\//g; + $INC{"${name}.pm"} = 'Set by "use Web::Simple;" invocation'; } +=head1 NAME + +Web::Simple - A quick and easy way to build simple web applications + +=head1 WARNING + +This is really quite new. If you're reading this on CPAN, it means the stuff +that's here we're probably happy with. But only probably. So we may have to +change stuff. And if you're reading this from git, come check with irc.perl.org +#web-simple that we're actually sure we're going to keep anything that's +different from the CPAN version. + +If we do find we have to change stuff we'll add to the +L section explaining how to switch your code across +to the new version, and we'll do our best to make it as painless as possible +because we've got Web::Simple applications too. But we can't promise not to +change things at all. Not yet. Sorry. + +=head1 SYNOPSIS + + #!/usr/bin/perl + + use Web::Simple 'HelloWorld'; + + { + package HelloWorld; + + dispatch { + sub (GET) { + [ 200, [ 'Content-type', 'text/plain' ], [ 'Hello world!' ] ] + }, + sub () { + [ 405, [ 'Content-type', 'text/plain' ], [ 'Method not allowed' ] ] + } + }; + } + + HelloWorld->run_if_script; + +If you save this file into your cgi-bin as 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, +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. + +The philosophy of 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 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 +might be just the thing for you. + +The Antiquated Perl talk can be found at L. + +=head1 DESCRIPTION + +The only public interface the Web::Simple module itself provides is an +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 + + use strict; + use warnings; + +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 +- i.e. does the equivalent of + + { + package NameOfApplication; + use base qw(Web::Simple::Application); + } + +It also exports the following subroutines: + + default_config( + key => 'value', + ... + ); + + dispatch { sub (...) { ... }, ... }; + + response_filter { ... }; + + redispatch_to '/somewhere'; + + subdispatch sub (...) { ... } + +and creates a $self global variable in your application package, so you can +use $self in dispatch subs without violating strict (Web::Simple::Application +arranges for dispatch subroutines to have the correct $self in scope when +this happens). + +Finally, import sets + + $INC{"NameOfApplication.pm"} = 'Set by "use Web::Simple;" invocation'; + +so that perl will not attempt to load the application again even if + + require NameOfApplication; + +is encountered in other code. + +=head1 DISPATCH STRATEGY + +=head2 Examples + + dispatch { + # matches: GET /user/1.htm?show_details=1 + # GET /user/1.htm + sub (GET + /user/* + ?show_details~ + .htm|.html|.xhtml) { + shift; my ($user_id, $show_details) = @_; + ... + }, + # matches: POST /user?username=frew + # POST /user?username=mst&first_name=matt&last_name=trout + sub (POST + /user + ?username=&*) { + shift; my ($username, $misc_params) = @_; + ... + }, + # matches: DELETE /user/1/friend/2 + sub (DELETE + /user/*/friend/*) { + shift; my ($user_id, $friend_id) = @_; + ... + }, + # matches: PUT /user/1?first_name=Matt&last_name=Trout + sub (PUT + /user/* + ?first_name~&last_name~) { + shift; my ($user_id, $first_name, $last_name) = @_; + ... + }, + sub (/user/*/...) { + my $user_id = $_[1]; + subdispatch sub { + [ + # matches: PUT /user/1/role/1 + sub (PUT + /role/*) { + my $role_id = $_[1]; + ... + }, + # matches: DELETE /user/1/role/1 + sub (DELETE + /role/*) { + my $role_id = shift; + ... + }, + ]; + } + }, + } + +=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 + +=item * call - a routine to call if this dispatcher matches (or has no match) + +=item * next - the next dispatcher to call + +=back + +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. + +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. + +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. + +If this routine returns (), Web::Simple treats this identically to a failure +to match. + +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. + +If this routine returns anything else, that is treated as the end of dispatch +and the value is returned. + +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. + +=head2 How Web::Simple builds dispatcher objects for you + +In the case of the Web::Simple L export the match is constructed +from the subroutine prototype - i.e. + + sub () { + + } + +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 - + + sub () { + [ 404, [ 'Content-type', 'text/plain' ], [ 'Error: Not Found' ] ] + } + +will produce a 404 result instead of a 500 by default. You can also override +the L method in your app. + +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: + + sub () { + my ($self, @args) = @_; + ... + } + +=head2 Web::Simple match specifications + +=head3 Method matches + + sub (GET) { + +A match specification beginning with a capital letter matches HTTP requests +with that request method. + +=head3 Path matches + + sub (/login) { + +A match specification beginning with a / is a path match. In the simplest +case it matches a specific path. To match a path with a wildcard part, you +can do: + + sub (/user/*) { + $self->handle_user($_[1]) + +This will match /user/ where does not include a literal +/ character. The matched part becomes part of the match arguments. You can +also match more than one part: + + sub (/user/*/*) { + my ($self, $user_1, $user_2) = @_; + + sub (/domain/*/user/*) { + my ($self, $domain, $user) = @_; + +and so on. To match an arbitrary number of parts, use - + + sub (/page/**) { + +This will result in an element per /-separated part so matched. Note that +you can do + + sub (/page/**/edit) { + +to match an arbitrary number of parts up to but not including some final +part. + +Finally, + + 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. + +Note that the '...' is a "maybe something here, maybe not" so the above +specification will match like this: + + /foo # no match + /foo/ # match and strip path to '/' + /foo/bar/baz # match and strip path to '/bar/baz' + +=head3 Extension matches + + 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. + + sub (.html) { + response_filter { $self->render_html($_[1]) } + } + +Additionally, + + sub (.*) { + +will match any extension and supplies the stripped extension as a match +argument. + +=head3 Query and body parameter matches + +Query and body parameters can be match via + + sub (?) { # match URI query + sub (%) { # match body params + +The body is only matched if the content type is +application/x-www-form-urlencoded (note this means that Web::Simple does +not yet handle uploads; this will be addressed in a later release). + +The param spec is elements of one of the following forms - + + param~ # optional parameter + param= # required parameter + @param~ # optional multiple parameter + @param= # required multiple parameter + :param~ # optional parameter in hashref + :param= # required parameter in hashref + :@param~ # optional multiple in hashref + :@param= # required multiple in hashref + * # include all other parameters in hashref + @* # include all other parameters as multiple in hashref + +separated by the & character. The arguments added to the request are +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 +would write: + + sub (?page=&order_by~) { + my ($self, $page, $order_by) = @_; + return unless $page =~ /^\d+$/; + $page ||= 'id'; + response_filter { + $_[1]->search_rs({}, $p); + } + } + +to implement paging and ordering against a L object. + +Note that if a parameter is specified as single and multiple values are found, +the last one will be used. + +To get all parameters as a hashref of arrayrefs, write: + + sub(?@*) { + my ($self, $params) = @_; + ... + +To get two parameters as a hashref, write: + + sub(?:user~&:domain~) { + my ($self, $params) = @_; # params contains only 'user' and 'domain' keys + +You can also mix these, so: + + sub (?foo=&@bar~&:coffee=&@*) { + my ($self, $foo, $bar, $params); + +where $bar is an arrayref (possibly an empty one), and $params contains +arrayref values for all parameters -not- mentioned and a scalar value for +the 'coffee' parameter. + +=head3 Combining matches + +Matches may be combined with the + character - e.g. + + sub (GET + /user/*) { + +to create an AND match. They may also be combined withe the | character - e.g. + + sub (GET|POST) { + +to create an OR match. Matches can be nested with () - e.g. + + sub ((GET|POST) + /user/*) { + +and negated with ! - e.g. + + sub (!/user/foo + /user/*) { + +! binds to the immediate rightmost match specification, so if you want +to negate a combination you will need to use + + sub ( !(POST|PUT|DELETE) ) { + +and | binds tighter than +, so + + sub ((GET|POST) + /user/*) { + +and + + sub (GET|POST + /user/*) { + +are equivalent, but + + sub ((GET + .html) | (POST + .html)) { + +and + + sub (GET + .html | POST + .html) { + +are not - the latter is equivalent to + + sub (GET + (.html|POST) + .html) { + +which will never match. + +=head3 Whitespace + +Note that for legibility you are permitted to use whitespace - + + sub (GET + /user/*) { + +but it will be ignored. This is because the perl parser strips whitespace +from subroutine prototypes, so this is equivalent to + + sub (GET+/user/*) { + +=head1 EXPORTED SUBROUTINES + +=head2 default_config + + default_config( + one_key => 'foo', + another_key => 'bar', + ); + + ... + + $self->config->{one_key} # 'foo' + +This creates the default configuration for the application, by creating a + + sub _default_config { + return (one_key => 'foo', another_key => 'bar'); + } + +in the application namespace when executed. Note that this means that +you should only run default_config once - calling it a second time will +cause an exception to be thrown. + +=head2 dispatch + + dispatch { + sub (GET) { + [ 200, [ 'Content-type', 'text/plain' ], [ 'Hello world!' ] ] + }, + sub () { + [ 405, [ 'Content-type', 'text/plain' ], [ 'Method not allowed' ] ] + } + }; + +The dispatch subroutine calls NameOfApplication->_setup_dispatcher with +the return value of the block passed to it, which then creates your Web::Simple +application's dispatcher from these subs. The prototype of each subroutine +is expected to be a Web::Simple dispatch specification (see +L below for more details), and the body of the +subroutine is the code to execute if the specification matches. + +Each dispatcher is given the dispatcher constructed from the next subroutine +returned as its next dispatcher, except for the final subroutine, which +is given the return value of NameOfApplication->_build_final_dispatcher +as its next dispatcher (by default this returns a 500 error response). + +See L below for details on how the Web::Simple dispatch +system uses the return values of these subroutines to determine how to +continue, alter or abort dispatch. + +Note that _setup_dispatcher creates a + + sub _dispatcher { + return ; + } + +method in your class so as with default_config, calling dispatch a second time +will result in an exception. + +=head2 response_filter + + response_filter { + # Hide errors from the user because we hates them, preciousss + if (ref($_[1]) eq 'ARRAY' && $_[1]->[0] == 500) { + $_[1] = [ 200, @{$_[1]}[1..$#{$_[1]}] ]; + } + return $_[1]; + }; + +The response_filter subroutine is designed for use inside dispatch subroutines. + +It creates and returns a special dispatcher that always matches, and calls +the block passed to it as a filter on the result of running the rest of the +current dispatch chain. + +Thus the filter above runs further dispatch as normal, but if the result of +dispatch is a 500 (Internal Server Error) response, changes this to a 200 (OK) +response without altering the headers or body. + +=head2 redispatch_to + + redispatch_to '/other/url'; + +The redispatch_to subroutine is designed for use inside dispatch subroutines. + +It creates and returns a special dispatcher that always matches, and instead +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 +'/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. + +=head1 CHANGES BETWEEN RELEASES + +=head2 Changes since Antiquated Perl + +=over 4 + +=item * filter_response renamed to response_filter + +This is a pure rename; a global search and replace should fix it. + +=item * dispatch [] changed to dispatch {} + +Simply changing + + dispatch [ sub(...) { ... }, ... ]; + +to + + dispatch { sub(...) { ... }, ... }; + +should work fine. + +=back + +=head1 COMMUNITY AND SUPPORT + +=head2 IRC channel + +irc.perl.org #web-simple + +=head2 No mailing list yet + +Because mst's non-work email is a bombsite so he'd never read it anyway. + +=head2 Git repository + +Gitweb is on http://git.shadowcat.co.uk/ and the clone URL is: + + git clone git://git.shadowcat.co.uk/catagits/Web-Simple.git + +=head1 AUTHOR + +Matt S. Trout + +=head1 CONTRIBUTORS + +None required yet. Maybe this module is perfect (hahahahaha ...). + +=head1 COPYRIGHT + +Copyright (c) 2009 the Web::Simple L and L +as listed above. + +=head1 LICENSE + +This library is free software and may be distributed under the same terms +as perl itself. + +=cut + 1;