use strict;
use warnings FATAL => 'all';
-sub import {
+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);
}
{
no strict 'refs';
*{"${app_package}::dispatch"} = sub {
- $app_package->_setup_dispatchables(@_);
+ $app_package->_setup_dispatcher(@_);
};
- *{"${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
=head1 WHY?
-While I originally wrote Web::Simple as part of my Antiquated Perl talk for
-Italian Perl Workshop 2009, I've found that having a bare minimum system for
-writing web applications that doesn't drive me insane is rather nice.
+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;
dispatch [ sub (...) { ... }, ... ];
- filter_response { ... };
+ response_filter { ... };
redispatch_to '/somewhere';
-and creates the $self global variable in your application package, so you can
+ 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 EXPORTED SUBROUTINES
=head2 default_config
}
in the application namespace when executed. Note that this means that
-you should only run default_config once - a second run will cause a warning
-that you are override the _default_config method in your application, which
-under Web::Simple will of course be fatal.
+you should only run default_config once - calling it a second time will
+cause an exception to be thrown.
=head2 dispatch
}
];
-The dispatch subroutine calls NameOfApplication->_setup_dispatchables with
-the subroutines passed to it, which then create's your Web::Simple
+The dispatch subroutine calls NameOfApplication->_setup_dispatcher with
+the subroutines passed to it, which then creates your Web::Simple
application's dispatcher from these subs. The prototype of the subroutine
is expected to be a Web::Simple dispatch specification (see
L</DISPATCH SPECIFICATIONS> below for more details), and the body of the
-subroutine is the code to execute if the specification matches. See
-L</DISPATCH STRATEGY> below for details on how the Web::Simple dispatch
+subroutine is the code to execute if the specification matches.
+
+Each dispatcher is given the dispatcher constructed from the next element
+of the arrayref as its next dispatcher, except for the final element, 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</DISPATCH STRATEGY> 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_dispatchables creates a
+Note that _setup_dispatcher creates a
- sub _dispatchables {
- return (<dispatchable objects here>);
+ sub _dispatcher {
+ return <root dispatcher object here>;
}
method in your class so as with default_config, calling dispatch a second time
-will result in a fatal warning from your application.
+will result in an exception.
=head2 response_filter
The response_filter subroutine is designed for use inside dispatch subroutines.
-It creates and returns a response filter object to the dispatcher,
-encapsulating the block passed to it as the filter routine to call. See
-L</DISPATCH STRATEGY> below for how a response filter affects dispatch.
+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.
-1;
+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 DISPATCH STRATEGY
+
+=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</dispatch> export the match is constructed
+from the subroutine prototype - i.e.
+
+ sub (<match specification>) {
+ <call code>
+ }
+
+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<Web::Simple::Application/_build_final_dispatcher> 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 (<match specification>) {
+ 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/<anything> where <anything> 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 (?<param spec>) { # match URI query
+ sub (%<param spec>) { # 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
+ * # include all other parameters
+ @* # include all other parameters as multiple
+
+separated by the & character.
+
+So, to match a page parameter with an optional order_by parameter one
+would write:
+
+ sub (?page=&order_by~) {
+
+Parameters selected are turned into a hashref; in the case of singular
+parameters then if multiple values are found the last one is used. In the
+case of multiple parameters an arrayref of all values (or an empty arrayref
+for a missing optional) is used. The resulting hashref is provided as a
+match argument. So we might write something like:
+
+ sub (?page=&order_by~) {
+ my ($self, $p) = @_;
+ return unless $p->{page} =~ /^\d+$/;
+ $p->{order_by} ||= 'id';
+ response_filter {
+ $_[1]->search_rs({}, $p);
+ }
+ }
+
+to implement paging and ordering against a L<DBIx::Class::ResultSet> object.
+
+=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/*) {
+
+=cut
1;
projects / catagits/Web-Simple.git / blobdiff