Simply adding templated pages

In the 0.9dev you can now add a page without changing dispatch rules.

TL;DR;

When (in 0.9dev) you add a template like:

/templates/static/hello.tpl

Then the request:

http://example.com/hello

will serve that template.
Without adding any dispatch rules.

Long version:

We added a new notification to the 0.9dev.
It is called #dispatch{} and is used by the site dispatcher to find a matching dispatch rule when no rule matched.

The #dispatch{} observer can return:

• {ok, integer()} where the integer is a rsc id
• {ok, #dispatch_match{}} with a webmachine resource and options filled in
• {ok, #dispatch_redirect{}} to redirect to a location (must be a fully qualified url!)
• undefined

With an 'undefined' other modules will be checked and finally a 404 might be served.

In mod_base I added a handler for the #dispatch{} notification:

%% @doc Check if there is a resource or template matching the path.
observe_dispatch(#dispatch{path=Path}, Context) ->
 case m_rsc:page_path_to_id(Path, Context) of
   {ok, Id} ->
     {ok, Id};
   {error, _} ->
     Template = "static/"++Path++".tpl",
     case z_module_indexer:find(template, Template, Context) of
       {ok, _} ->
         {ok, #dispatch_match{
             mod=resource_template,
             mod_opts=[{template, Template}, {ssl, any}],
             bindings=[{path, Path}, {is_static, true}]
         }};
       {error, _} ->
         undefined
     end
 end.

This does two things:

1. 1. Check if there is resource with a set page path, if so return it's id
2. 2. Check if there is a template in a 'static/' directory with the name of the request path. If so then this template is served using the resource_template module.