SYNOPSIS

DESCRIPTION

    Perinci::Access::HTTP::Server (PeriAHS for short) is a PSGI application
    (a set of middlewares in Plack::Middleware::PeriAHS::*, really) to
    implement Riap::HTTP server. You compose the middlewares, configuring
    each one and including only the ones you need, in your app.psgi, to
    create an API service.

    A simple command-line utility, peri-htserve, is also available
    (distributed separately, see App::PerinciUtils). This utility runs a
    provided PSGI application with the Gepok or Starman PSGI server so you
    can quickly export some Perl modules/functions as an API service with
    one line of command.

    To get started, currently see the source code of peri-htserve to see
    the basic structure of the PSGI application. Also see each middleware's
    documentation.

FAQ

 I don't want to have to add metadata to every function!

    The point of Riap::HTTP is to expose metadata over HTTP, so it's best
    that you write your metadata for every API function you want to expose.

    However, there are tools like Perinci::Gen::ForModule (which the
    peri-htserve CLI uses) which can generate some (generic) metadata for
    your existing modules.

 How can I customize URL?

    For example, instead of:

     http://localhost:5000/My/API/Adder/func

    you want:

     http://localhost:5000/adder/func

    or perhaps (if you only have one module to expose):

     http://localhost:5000/func

    You can do this by customizing match_uri when enabling the
    PeriAHS::ParseRequest middleware (see peri-htserve source code). You
    just need to make sure that you set $env->{"riap.request"}{uri}.

 I want to let user specify output format from URI (e.g. /api/j/... or
 /api/yaml/...).

    Again, this can be achieved by customizing the PeriAHS::ParseRequest
    middleware. You can do something like:

     enable "PeriAHS::ParseRequest"
         match_uri => [
             qr!^/api/(?<f>json|yaml|j|y)/
                      (?<uri>[^?/]+(?:/[^?/]+)?)!x,
             sub {
                 my ($env, $m) = @_;
                 $env->{"riap.request"}{fmt} = $m->{f} =~ /j/ ? 'json' : 'yaml';
             }
         ];

    Another example, allowing format by sticking .json or .yaml at the end
    of Riap URI:

     enable "PeriAHS::ParseRequest"
         match_uri => qr!^(?<uri>[^?/]+(?:/[^?/]+)?)(?:\.(?<fmt>json|yaml))!x;

 I need even more custom URI syntax.

    You can leave match_uri empty and perform your custom URI parsing in
    another middleware after PeriAHS::ParseRequest. For example:

     enable "PeriAHS::ParseRequest";
    
     # do more URI parsing
     enable sub {
         my $app = shift;
         sub {
             my $env     = shift;
             my $rreq    = $env->{"riap.request"};
             # parse more stuff and put it in $rreq
             my $res = $app->($env);
             return $res;
         };
     };

 I want to support HTTPS.

    If you use peri-htserve, supply --https_ports, --ssl_key_file and
    --ssl_cert_file options.

    If you use plackup, use Gepok (-s) as the PSGI server.

    If you use PSGI server other than Gepok, you will probably need to run
    Nginx, Perlbal, or some other external HTTPS proxy.

 I don't want to run a standalone daemon.

    Use other deployment mechanisms for your PSGI application, of which
    there are plenty. For example, to deploy as CGI script, see
    Plack::Handler::CGI. To deploy as FastCGI script (allowing to run under
    Nginx, for example), see Plack::Handler::FCGI.

 I don't want to expose my subroutines and module structure directly!

    Well, isn't exposing functions the whole point of API?

    If you have modules that you do not want to expose as API, simply
    disallow it (e.g. using allowed_uris configuration in
    PeriAHS::ParseRequest middleware. Or, create a set of wrapper modules
    to expose only the functionalities that you want to expose.

 But I want REST-style!

    Take a look at Serabi.

 I want to support another output format (e.g. XML, MessagePack, etc).

    See Perinci::Result::Format.

 I want to automatically reload modules that changed on disk.

    Use one of the module-reloading module on CPAN, e.g.: Module::Reload or
    Module::Reload::Conditional.

 I want to authenticate clients.

    Enable Plack::Middleware::Auth::Basic (or other authen middleware you
    prefer) before PeriAHS::ParseRequest.

 I want to add access control and/or authorize clients.

    Take a look at Plack::Middleware::PeriAHS::ACL (currently unfinished)
    which allows access control based on various conditions. Normally this
    is put after authentication and before response creation.

 I want to support new actions.

    Normally you'll need to extend the appropriate Riap clients (e.g.
    Perinci::Access::Schemeless for this. Again, note that you don't have
    to resort to subclassing just to accomplish this. You can inject the
    action_ACTION() method from somewhere else.

 I want to serve static files.

    Use the usual Plack::Builder's mount() and Plack::Middleware::Static
    for this.

     mount my $app = builder {
         mount "/api" => builder {
             enable "PeriAHS::ParseRequest", ...;
             ...
         },
         mount "/static" => builder {
             enable "Static", path=>..., root=>...;
         },
     };

TIPS AND TRICKS

 Proxying API server

    Not only can you serve local modules, you can also serve remote modules
    ("http://" or "https://" URIs) making your API server a proxy for
    another.

 Performance tuning

    To be written.

SEE ALSO

    Perinci::Access

    Riap::HTTP

    Serabi