.TH mod_esi 3erl "inets 6.3.4" "Ericsson AB" "Erlang Module Definition"
.SH NAME
mod_esi \- Erlang Server Interface
.SH DESCRIPTION
.LP
This module defines the Erlang Server Interface (ESI) API\&. It is a more efficient way of writing Erlang scripts for your \fIInets\fR\& web server than writing them as common CGI scripts\&.
.SH "DATA TYPES"

.LP
The following data types are used in the functions for mod_esi:
.RS 2
.TP 2
.B
\fIenv() = \fR\&:
\fI{EnvKey()::atom(), Value::term()}\fR\&
.RS 2
.LP
Currently supported key value pairs
.RE

.RS 2
.TP 2
.B
\fI{server_software, string()}\fR\&:
Indicates the inets version\&.
.TP 2
.B
\fI{server_name, string()}\fR\&:
The local hostname\&.
.TP 2
.B
\fI{gateway_interface, string()}\fR\&:
Legacy string used in CGI, just ignore\&.
.TP 2
.B
\fI{server_protocol, string()}\fR\&:
HTTP version, currently "HTTP/1\&.1"
.TP 2
.B
\fI{server_port, integer()}\fR\&:
Servers port number\&.
.TP 2
.B
\fI{request_method, "GET | "PUT" | "DELETE" | "POST" | "PATCH"}\fR\&:
HTTP request method\&.
.TP 2
.B
\fI{remote_adress, inet:ip_address()} \fR\&:
The clients ip address\&.
.TP 2
.B
\fI{peer_cert, undefined | no_peercert | DER:binary()}\fR\&:
For TLS connections where client certificates are used this will be an ASN\&.1 DER-encoded X509-certificate as an Erlang binary\&. If client certificates are not used the value will be \fIno_peercert\fR\&, and if TLS is not used (HTTP or connection is lost due to network failure) the value will be \fIundefined\fR\&\&.
.TP 2
.B
\fI{script_name, string()}\fR\&:
Request URI
.TP 2
.B
\fI{http_LowerCaseHTTPHeaderName, string()}\fR\&:
example: {http_content_type, "text/html"}
.RE
.RE
.SH EXPORTS
.LP
.B
deliver(SessionID, Data) -> ok | {error, Reason}
.br
.RS
.LP
Types:

.RS 3
SessionID = term()
.br
Data = string() | io_list() | binary()
.br
Reason = term()
.br
.RE
.RE
.RS
.LP
This function is \fIonly\fR\& intended to be used from functions called by the Erl Scheme interface to deliver parts of the content to the user\&.
.LP
Sends data from an Erl Scheme script back to the client\&.
.LP

.RS -4
.B
Note:
.RE
If any HTTP header fields are added by the script, they must be in the first call to \fIdeliver/2\fR\&, and the data in the call must be a string\&. Calls after the headers are complete can contain binary data to reduce copying overhead\&. Do not assume anything about the data type of \fISessionID\fR\&\&. \fISessionID\fR\& must be the value given as input to the ESI callback function that you implemented\&.

.RE

.SH "ESI CALLBACK FUNCTIONS"

.SH EXPORTS
.LP
.B
Module:Function(SessionID, Env, Input)-> _ 
.br
.RS
.LP
Types:

.RS 3
SessionID = term()
.br
Env = env()
.br
Input = string()
.br
.RE
.RE
.RS
.LP
\fIModule\fR\& must be found in the code path and export \fIFunction\fR\& with an arity of three\&. An \fIerlScriptAlias\fR\& must also be set up in the configuration file for the web server\&.
.LP
If the HTTP request is a \&'post\&' request and a body is sent, \fIcontent_length\fR\& is the length of the posted data\&. If \&'get\&' is used, \fIquery_string\fR\& is the data after \fI?\fR\& in the URL\&.
.LP
\fIParsedHeader\fR\& is the HTTP request as a key-value tuple list\&. The keys in \fIParsedHeader\fR\& are in lower case\&.
.LP
\fISessionID\fR\& is an identifier the server uses when \fIdeliver/2\fR\& is called\&. Do not assume anything about the datatype\&.
.LP
Use this callback function to generate dynamic web content dynamically\&. When a part of the page is generated, send the data back to the client through \fIdeliver/2\fR\&\&. Notice 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 does not contain the \fIend of HTTP header\fR\&, that is, \fI"\\r\\n\\r\\n",\fR\& the server assumes that no HTTP header fields will be generated\&.
.RE

.LP
.B
Module:Function(Env, Input)-> Response 
.br
.RS
.LP
Types:

.RS 3
Env = env()
.br
Input = string()
.br
Response = string()
.br
.RE
.RE
.RS
.LP
This callback format consumes much memory, as the whole response must be generated before it is sent to the user\&. This function is deprecated and is only kept for backwards compatibility\&. For new development, use \fIModule:Function/3\fR\&\&.
.RE