Ocamlnet 3 Reference Manual : Netcgi_plex

# Module Netcgi_plex

    module Netcgi_plex: sig .. end

# Netplex support for FastCGI, SCGI and AJP connectors

## Factory

    val factory : ?config:Netcgi.config ->
           ?enable:[ `AJP | `FCGI | `SCGI ] list ->
           ?name:string ->
           ?output_type:Netcgi.output_type ->
           ?arg_store:Netcgi.arg_store ->
           ?exn_handler:Netcgi.exn_handler ->
           ?configure:(Netplex_types.config_file ->
                       Netplex_types.address -> Netplex_types.processor_hooks) ->
           (Netplex_types.container -> Netcgi.cgi -> unit) ->
           Netplex_types.processor_factory

Reads a Netplex configuration section like

        processor {
          type = "netcgi";          (* or the overridden [name] *)
          timeout = 15;             (* optional *)
          mount_dir = "/url/path";  (* optional *)
          mount_at = "/url/path";   (* optional alternative to mount_dir *)
        }

and creates a processor for the protocols "fcgi", "scgi", and "ajp" (or a subset of these protocols if the `enable` parameter restricts them). A complete service definition looks thus like:

          service {
              name = "name_of_service";
              protocol {
                  name = "fcgi";        (* or "scgi" or "ajp" *)
                  address {
                      type = "internet";
                      bind = "localhost:<port>";
                  };
              };
              (* ... several protocol sections allowed! *)
              processor {
                  type = "netcgi";
              };
              workload_manager {
                  type = "dynamic";
                  max_jobs_per_thread = 1;  (* only reasonable value *)
                  min_free_job_capacity = <n>;
                  max_free_job_capacity = <n>;
                  max_threads = <n>;
              };
          }

The processor calls the argument function of type `container -> cgi -> unit` for every incoming request.

The `timeout` parameter specifies when inactive connections are timed out (in seconds). The `mount_dir` and `mount_at` parameters define which part of the URL is considered as `SCRIPT_NAME`:

- By default (if neither `mount_dir` nor `mount_at`) are given `SCRIPT_NAME` is determined in a protocol-dependent way. Usually, the server transmits `SCRIPT_NAME`, but see the note below.
- If `mount_dir` is present, the processor accepts only URLs that have this path as true prefix directory, i.e. the URL path is `<mount_dir>/<name><rest>`. The part `<mount_dir>/<name>` is taken as `SCRIPT_NAME`.
- If `mount_at` is present, the processor accepts only URLs that have this path as prefix, i.e. the URL path is `<mount_at><rest>`. `<mount_at>` is taken as `SCRIPT_NAME`.

The background is that `SCRIPT_NAME` is commonly used to distinghuish between different web actions of the netcgi application. The actions are simply names in a directory like `/bin/<name>` or `/servlet/<name>`. Not all web servers/protocols transmit good values for `SCRIPT_NAME`, however. By specifying `mount_dir` or `mount_at` one can force to interpret a certain prefix of the request URL as `SCRIPT_NAME`.

`config` : The Netcgi configuration to use, default is `Netcgi.default_config`
`enable` : Which protocols to support. Default is to support all protocols
`name` : Defines the name of the processor. Default is "netcgi".
`output_type` : Default: ``Direct ""`
`arg_store` : Default: ``Automatic` for all arguments.
`exn_handler` : See `Netcgi.exn_handler`. Default: delegate all exceptions to the default handler.
`configure` : Parameters are the netplex configuration file and the address of the `processor` section. The configure function can look for additional parameters. It returns service hooks that are added to the resulting processor.

## Processors

The following functions create the processors directly

    type mountpoint = [ `Mount_at of string | `Mount_dir of string ]

    val fcgi_processor : ?config:Netcgi.config ->
           ?output_type:Netcgi.output_type ->
           ?arg_store:Netcgi.arg_store ->
           ?exn_handler:Netcgi.exn_handler ->
           ?timeout:float ->
           ?mount:mountpoint ->
           (Netplex_types.container -> Netcgi_fcgi.cgi -> unit) ->
           Netplex_types.processor

    val scgi_processor : ?config:Netcgi.config ->
           ?output_type:Netcgi.output_type ->
           ?arg_store:Netcgi.arg_store ->
           ?exn_handler:Netcgi.exn_handler ->
           ?timeout:float ->
           ?mount:mountpoint ->
           (Netplex_types.container -> Netcgi.cgi -> unit) -> Netplex_types.processor

    val ajp_processor : ?config:Netcgi.config ->
           ?output_type:Netcgi.output_type ->
           ?arg_store:Netcgi.arg_store ->
           ?exn_handler:Netcgi.exn_handler ->
           ?timeout:float ->
           ?mount:mountpoint ->
           (Netplex_types.container -> Netcgi.cgi -> unit) -> Netplex_types.processor