Module `Ocsigen_extensions`

Extensions interface for Ocsigen Server

val section : Logs.src

include module type of Ocsigen_command

exception Unknown_command

val register_command_function : 
  ?prefix:string ->
  (string -> string list -> unit Lwt.t) ->
  unit

Use a prefix for all your commands when you want to create extension-specific commands. For example if the prefix is "myextension" and the commande "blah", the actual command to be written by the user is "myextension:blah". Give as parameter the function that will parse the command and do an action. Its first parameter is the full command as a string. The second one is the command without prefix, split by word. It must raise ocsigen_extensions.Unknown_command if it does not recognize the command.

exception Ocsigen_http_error of Ocsigen_cookie_map.t * Cohttp.Code.status

exception Bad_config_tag_for_extension of string

Xml tag not recognized by an extension (usually not a real error)

exception Error_in_config_file of string

Error in a <site> tag inside the main ocsigen.conf file

exception Error_in_user_config_file of string

Option incorrect in a userconf file

type file_info = Ocsigen_multipart.file_info = {

tmp_filename : string;
filesize : int64;
raw_original_filename : string;
file_content_type : ((string * string) * (string * string) list) option;

}

val badconfig : ('a, unit, string, 'b) Stdlib.format4 -> 'a

Convenient function for raising Error_in_config_file exceptions with a sprintf-formatted argument.

type virtual_hosts = (string * Re.Pcre.regexp * int option) list

Type of the result of parsing the field hostfiler in the configuration file. Inside the list, the first argument is the host itself (which is a glob-like pattern that can contains *), a regexp parsing this pattern, and optionally a port.

val hash_virtual_hosts : virtual_hosts -> int

val equal_virtual_hosts : virtual_hosts -> virtual_hosts -> bool

val host_match : 
  virtual_hosts:virtual_hosts ->
  host:string option ->
  port:int ->
  bool

type do_not_serve = {

do_not_serve_regexps : string list;
do_not_serve_files : string list;
do_not_serve_extensions : string list;

}

Configuration to hide/forbid local files

val serve_everything : do_not_serve

exception IncorrectRegexpes of do_not_serve

val do_not_serve_to_regexp : do_not_serve -> Re.Pcre.regexp

Compile a do_not_serve structure into a regexp. Raises IncorrectRegexpes if the compilation fails. The result is memoized for subsequent calls with the same argument

val join_do_not_serve : do_not_serve -> do_not_serve -> do_not_serve

type config_info = {

default_hostname : string;
default_httpport : int;
default_httpsport : int;
default_protocol_is_https : bool;
mime_assoc : Ocsigen_charset_mime.mime_assoc;
charset_assoc : Ocsigen_charset_mime.charset_assoc;
default_directory_index : string list;
(*
Default name to use as index file when a directory is requested. Use None if no index should be tried. The various indexes are tried in the given order. If no index is specified, or the index does not exists, the content of the directory might be listed, according to list_directory_content
*)
list_directory_content : bool;
(*
Should the list of files in a directory be displayed if there is no index in this directory ?
*)
follow_symlinks : [ `No | `Owner_match | `Always ];
(*
Should symlinks be followed when accessing a local file?
*)
do_not_serve_404 : do_not_serve;
do_not_serve_403 : do_not_serve;
uploaddir : string option;
maxuploadfilesize : int64 option;

}

Configuration options, passed to (and modified by) extensions

val default_config_info : unit -> config_info

type request = {

request_info : Ocsigen_request.t;
request_config : config_info;

}

exception Ocsigen_is_dir of Ocsigen_request.t -> Uri.t

type answer =

| Ext_do_nothing
(*
I don't want to do anything
*)
| Ext_found of unit -> Ocsigen_response.t Lwt.t
(*
"OK stop! I will take the page. You can start the following request of the same pipelined connection. Here is the function to generate the page". The extension must return Ext_found as soon as possible when it is sure it is safe to start next request. Usually immediately. But in some case, for example proxies, you don't want the request of one connection to be handled in different order. (for example revproxy.ml starts its requests to another server before returning Ext_found, to ensure that all requests are done in same order).
*)
| Ext_found_stop of unit -> Ocsigen_response.t Lwt.t
(*
Found but do not try next extensions
*)
| Ext_next of Cohttp.Code.status
(*
Page not found. Try next extension. The status is usually `Not_found, but may be for example `Forbidden (403) if you want to try another extension afterwards. Same as Ext_continue_with but does not change the request.
*)
| Ext_stop_site of Ocsigen_cookie_map.t * Cohttp.Code.status
(*
Error. Do not try next extension, but try next site.
*)
| Ext_stop_host of Ocsigen_cookie_map.t * Cohttp.Code.status
(*
Error. Do not try next extension, do not try next site, but try next host.
*)
| Ext_stop_all of Ocsigen_cookie_map.t * Cohttp.Code.status
(*
Error. Do not try next extension, do not try next site, do not try next host.
*)
| Ext_continue_with of request * Ocsigen_cookie_map.t * Cohttp.Code.status
(*
Used to modify the request before giving it to next extension. The extension returns the request (possibly modified) and a set of cookies if it wants to set or cookies (Ocsigen_cookie_map.empty for no cookies). You must add these cookies yourself in request if you want them to be seen by subsequent extensions, for example using Ocsigen_http_frame.compute_new_ri_cookies. The status is usually equal to the one received from preceding extension (but you may want to modify it).
*)
| Ext_retry_with of request * Ocsigen_cookie_map.t
(*
Used to retry all the extensions with a new request. The extension returns the request (possibly modified) and a set of cookies if it wants to set or cookies (Ocsigen_cookie_map.empty for no cookies). You must add these cookies yourself in request if you want them to be seen by subsequent extensions, for example using Ocsigen_http_frame.compute_new_ri_cookies.
*)
| Ext_sub_result of extension_composite
(*
Used if your extension want to define option that may contain other options from other extensions. In that case, while parsing the configuration file, call the parsing function (of type parse_fun), that will return something of type extension_composite.
*)
| Ext_found_continue_with of unit -> (Ocsigen_response.t * request) Lwt.t
(*
Same as Ext_found but may modify the request.
*)
| Ext_found_continue_with' of Ocsigen_response.t * request
(*
Same as Ext_found_continue_with but does not allow to delay the computation of the page. You should probably not use it, but for output filters.
*)

and request_state =

| Req_not_found of Cohttp.Code.status * request
| Req_found of request * Ocsigen_response.t

and extension_composite =
  Ocsigen_cookie_map.t ->
  request_state ->
  (answer * Ocsigen_cookie_map.t) Lwt.t

type extension = request_state -> answer Lwt.t

For each <site> tag in the configuration file, you can set the extensions you want. Each extension is implemented as a function, taking the charset found in configuration file, the current state of the request, and returning an answer. If no page has been generated so far (Req_not_found), it receive the error code given by the previous extension (default 404), and the request information. If a page has been generated by previous extensions (case Req_found), the extension may want to modify the result (filters).

type parse_fun = Xml.xml list -> extension_composite

type parse_host

Type of the functions parsing the content of a <host> tag

type userconf_info = {

localfiles_root : string;

}

Information received by extensions accepting userconf files.

The parameter localfiles_root is an absolute path to the directory that the user is allowed to serve. This is used by staticmod, to disallow the user from allowing access to outside of this directory

type parse_config =
  userconf_info option ->
  virtual_hosts ->
  config_info ->
  parse_config_aux

parse_config is the type of the functions parsing a <site> tag (and returning an extension). Those are functions taking

the name of the virtual <host>

that will be called for each <host>, and that will generate a function taking:

the path attribute of a <site> tag

that will be called for each <site>, and that will generate a function taking:

an item of the config file

that will be called on each tag inside <site> and:

raise Bad_config_tag_for_extension if it does not recognize that tag
return something of type extension (filter or page generator)

parse_config_user is the type of functions parsing a site tag inside an userconf file. They take one more parameter, of type userconf_info

and parse_config_aux =
  Ocsigen_lib.Url.path ->
  parse_host ->
  parse_fun ->
  Xml.xml ->
  extension

val register : 
  name:string ->
  ?fun_site:parse_config ->
  ?end_init:(unit -> unit) ->
  ?init_fun:(Xml.xml list -> unit) ->
  ?exn_handler:(exn -> string) ->
  ?respect_pipeline:bool ->
  unit ->
  unit

For each extension generating pages, we register its name and six functions:

a function fun_site of type parse_config. This function will be responsible for handling the options of the configuration files that are recognized by the extension, and potentially generating a page.
a function end_init that will be called at the end of the initialisation phase of each site
a function init_fun that will be called just before registering the extension, taking as parameter the configuration options between <extension> and </extension>. This allows to give configuration options to extensions. If no function is supplied, the extension is supposed to accept no option (and loading will fail if an option is supplied) See Configuration.process_elements for the easy construction of such a function.
a function exn_handler that will create an error message from the exceptions that may be raised during the initialisation phase, and raise again all other exceptions

Moreover, if the optional parameter ?respect_pipeline is true, the extension will ask the server to respect the order of the pipeline. That means that it will wait to be sure that the previous request from the same connection has been taken by an extension before giving a request to an extension. Use this to write proxies extensions, when you want to be able to pipeline the requests you to another server. It is false by default.

module Configuration : sig ... end

This modules contains types and constructor for the description of XML configurations and the accordingly parsing.

val get_hostname : request -> string

Returns the hostname to be used for absolute links or redirections. It is either the Host header or the hostname set in the configuration file.

val get_port : request -> int

Returns the port to be used for absolute links or redirections. It is either:

the port the server is listening at
or the port in the Host header
or the default port set in the configuration file.

val new_url_of_directory_request : request -> Ocsigen_request.t -> Uri.t

new_url_of_directory_request create a redirection and generating a new url for the client (depending on the server configuration and request)

parameter request
configuration of the server

parameter ri
request

User directories

Exception raised when an non-existing user is found

exception NoSuchUser

type ud_string

The type for string that may contain a $u(...)

val parse_user_dir : string -> ud_string

val replace_user_dir : Re.Pcre.regexp -> ud_string -> string -> string

raises Not_found is the directory does not exist

exception Not_concerned

Regular expressions for redirections

val find_redirection : 
  Re.Pcre.regexp ->
  bool ->
  string ->
  Ocsigen_request.t ->
  string