1mod_esi(3) Erlang Module Definition mod_esi(3)
2
6 mod_esi - Erlang Server Interface
7
9 This module defines the Erlang Server Interface (ESI) API. It is a more
10 efficient way of writing Erlang scripts for your Inets web server than
11 writing them as common CGI scripts.
12
14 The following data types are used in the functions for mod_esi:
15 env() = :
17 {EnvKey()::atom(), Value::term()}
18 Currently supported key value pairs
20 {server_software, string()}:
22 Indicates the inets version.
23 {server_name, string()}:
25 The local hostname.
26 {gateway_interface, string()}:
28 Legacy string used in CGI, just ignore.
29 {server_protocol, string()}:
31 HTTP version, currently "HTTP/1.1"
32 {server_port, integer()}:
34 Servers port number.
35 {request_method, "GET | "PUT" | "DELETE" | "POST" | "PATCH"}:
37 HTTP request method.
38 {remote_adress, inet:ip_address()} :
40 The clients ip address.
41 {peer_cert, undefined | no_peercert | DER:binary()}:
43 For TLS connections where client certificates are used this will
44 be an ASN.1 DER-encoded X509-certificate as an Erlang binary. If
45 client certificates are not used the value will be no_peercert,
46 and if TLS is not used (HTTP or connection is lost due to network
47 failure) the value will be undefined.
48 {script_name, string()}:
50 Request URI
51 {http_LowerCaseHTTPHeaderName, string()}:
53 example: {http_content_type, "text/html"}
54
56 deliver(SessionID, Data) -> ok | {error, Reason}
57 Types:
59 SessionID = term()
61 Data = string() | io_list() | binary()
62 Reason = term()
63 This function is only intended to be used from functions called
65 by the Erl Scheme interface to deliver parts of the content to
66 the user.
67 Sends data from an Erl Scheme script back to the client.
69 Note:
71 If any HTTP header fields are added by the script, they must be
72 in the first call to deliver/2, and the data in the call must be
73 a string. Calls after the headers are complete can contain
74 binary data to reduce copying overhead. Do not assume anything
75 about the data type of SessionID. SessionID must be the value
76 given as input to the ESI callback function that you imple‐
77 mented.
78
82 Module:Function(SessionID, Env, Input)-> {continue, State} | _
83 Types:
85 SessionID = term()
87 Env = env()
88 Input = string() | chunked_data()
89 chunked_data() = {first, Data::binary()} | {continue,
90 Data::binary(), State::term()} | {last, Data::binary(),
91 State::term()}
92 State = term()
93 Module must be found in the code path and export Function with
95 an arity of three. An erlScriptAlias must also be set up in the
96 configuration file for the web server.
97 mod_esi:deliver/2 shall be used to generate the response to the
99 client and SessionID is an identifier that shall by used when
100 calling this function, do not assume anything about the
101 datatype. This function may be called several times to chunk the
102 response data. Notice that the first chunk of data sent to the
103 client must at least contain all HTTP header fields that the
104 response will generate. If the first chunk does not contain the
105 end of HTTP header, that is, "\r\n\r\n", the server assumes that
106 no HTTP header fields will be generated.
107 Env environment data of the request see description above.
109 Input is query data of a GET request or the body of a PUT or
111 POST request. The default behavior (legacy reasons) for deliver‐
112 ing the body, is that the whole body is gathered and converted
113 to a string. But if the httpd config parameter
114 max_client_body_chunk is set, the body will be delivered as
115 binary chunks instead. The maximum size of the chunks is either
116 max_client_body_chunk or decide by the client if it uses HTTP
117 chunked encoding to send the body. When using the chunking mech‐
118 anism this callback must return {continue, State::term()} for
119 all calls where Input is {first, Data::binary()} or {continue,
120 Data::binary(), State::term()}. When Input is {last,
121 Data::binary(), State::term()} the return value will be ignored.
122 Note:
124 Note that if the body is small all data may be delivered in only
125 one chunk and then the callback will be called with {last,
126 Data::binary(), undefined} without getting called with {first,
127 Data::binary()}.
128 The input State is the last returned State, in it the callback
131 can include any data that it needs to keep track of when han‐
132 dling the chunks.
133 Module:Function(Env, Input)-> Response
135 Types:
137 Env = env()
139 Input = string()
140 Response = string()
141 This callback format consumes much memory, as the whole response
143 must be generated before it is sent to the user. This callback
144 format is deprecated. For new development, use Module:Func‐
145 tion/3.
146Ericsson AB inets 7.0.7 mod_esi(3)