# mod_esi

### MODULE

mod_esi

### MODULE SUMMARY

Erlang Server Interface

### DESCRIPTION

This module defines the API - Erlang Server Interface (ESI). Which is a more efficient way of writing erlang scripts for your Inets webserver than writing them as common CGI scripts.

### EXPORTS

`deliver(SessionID, Data) -> ok | {error, Reason}`

Types:

`SessionID = term()`
`Data = string() | io_list()`
`Reason = term()`

This function is only intended to be used from functions called by the Erl Scheme interface to deliver parts of the content to the user.

Sends data from a Erl Scheme script back to the client. Note that if any HTTP-header fields should be added by the script they must be in the first call to deliver/2 and the data in the call must be a string. Do not assume anything about the data type of SessionID, the SessionID must be the value given as input to the esi call back function that you implemented.

### ESI Callback Functions

### EXPORTS

`Module:Function(SessionID, Env, Input)-> _`

Types:

`SessionID = term()`
`Env = [EnvironmentDirectives] ++ ParsedHeader`
`EnvironmentDirectives = {Key,Value}`
`Key = query_string | content_length | server_software | gateway_interface | server_protocol | server_port | request_method | remote_addr | script_name. <v>Input = string()`

The `Module` must be found in the code path and export `Function` with an arity of two. An erlScriptAlias must also be set up in the configuration file for the Web server.

If the HTTP request is a post request and a body is sent then content_length will be the length of the posted data. If get is used query_string will be the data after ? in the url.

ParsedHeader is the HTTP request as a key value tuple list. The keys in parsed header will be the in lower case.

SessionID is a identifier the server use when `deliver/2` is called, do not assume any-thing about the datatype.

Use this callback function to dynamicly generate dynamic web content. when a part of the page is generated send the data back to the client through `deliver/2`. Note that the first chunk of data sent to the client must at least contain all HTTP header fields that the response will generate. If the first chunk not contains End of HTTP header that is `"\r\n\r\n"` the server will assume that no HTTP header fields will be generated.

`Module:Function(Env, Input)-> Response`

Types:

`Env = [EnvironmentDirectives] ++ ParsedHeader`
`EnvironmentDirectives = {Key,Value}`
`Key = query_string | content_length | server_software | gateway_interface | server_protocol | server_port | request_method | remote_addr | script_name. <v>Input = string()`
`Response = string()`

This callback format consumes quite much memory since the whole response must be generated before it is sent to the user.This functions is deprecated and only keept for backwards compability. For new development Module:Function/3 should be used.

### AUTHORS

Joakim Grebenö - support@erlang.ericsson.se
Ingela Anderton Andin - support@erlang.ericsson.se

inets 4.7.8
Copyright © 1991-2007 Ericsson AB