1%%
2%% %CopyrightBegin%
3%%
4%% Copyright Ericsson AB 2005-2016. All Rights Reserved.
5%%
6%% Licensed under the Apache License, Version 2.0 (the "License");
7%% you may not use this file except in compliance with the License.
8%% You may obtain a copy of the License at
9%%
10%%     http://www.apache.org/licenses/LICENSE-2.0
11%%
12%% Unless required by applicable law or agreed to in writing, software
13%% distributed under the License is distributed on an "AS IS" BASIS,
14%% WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
15%% See the License for the specific language governing permissions and
16%% limitations under the License.
17%%
18%% %CopyrightEnd%
19%%
20%%
21-module(httpd_cgi).
22
23-export([parse_headers/1, handle_headers/1]).
24
25-include_lib("inets/src/inets_app/inets_internal.hrl").
26
27
28%%%=========================================================================
29%%%  Internal application API
30%%%=========================================================================
31
32%%--------------------------------------------------------------------------
33%% parse_headers([Bin, Data, Header, Headers]) -> {RevHeaders, Body} |
34%%                                                {Module, Function, Args}
35%% Bin = Data = binary()
36%% Header = string() - Accumulator should be [] in first call
37%% Headers = [Header] - Accumulator should be [] in first call
38%% Body = string()
39%% RevHeaders = string() - Note CGI-headers not HTTP-headers
40%%
41%% Description: Parses "<<Bin/binary, Data/binary>>" returned from the
42%% CGI-script until it findes the end of the CGI-headers (at least one
43%% CGI-HeaderField must be supplied) then it returns the CGI-headers
44%% and maybe some body data. If {Module, Function, Args} is
45%% returned it means that more data needs to be collected from the
46%% cgi-script as the end of the headers was not yet found. When more
47%% data has been collected call Module:Function([NewData | Args]).
48%%
49%% NOTE: The headers are backwards and should
50%% be so, devide_and_reverse_headers will reverse them back after
51%% taking advantage of the fact that they where backwards.
52%%--------------------------------------------------------------------------
53parse_headers([Data, Bin,  Header, Headers]) ->
54    parse_headers(<<Bin/binary, Data/binary>>, Header, Headers).
55
56%%--------------------------------------------------------------------------
57%% handle_headers(CGIHeaders) -> {ok, HTTPHeaders, StatusCode} |
58%%                            {proceed, AbsPath}
59%%	CGIHeaders = [string()]
60%%	HTTPHeaders = [{HeaderField, HeaderValue}]
61%%      HeaderField = string()
62%%      HeaderValue = string()
63%%      StatusCode = integer()
64%%
65%% Description: Interprets CGI headers and creates HTTP headers and a
66%% appropriate HTTP status code. Note if a CGI location header is present
67%% the return value will be {proceed, AbsPath}
68%%--------------------------------------------------------------------------
69handle_headers(CGIHeaders) ->
70    handle_headers(CGIHeaders, [], {200, "ok"}).
71
72%%%========================================================================
73%%% Internal functions
74%%%========================================================================
75parse_headers(<<>>, Header, Headers) ->
76    {?MODULE, parse_headers, [<<>>, Header, Headers]};
77parse_headers(<<?CR,?LF>>, Header, Headers) ->
78    {?MODULE, parse_headers, [<<?CR,?LF>>, Header, Headers]};
79parse_headers(<<?LF>>, Header, Headers) ->
80    {?MODULE, parse_headers, [<<?LF>>, Header, Headers]};
81parse_headers(<<?CR, ?LF, ?CR, ?LF, Rest/binary>>, Header, Headers) ->
82    {ok, {[lists:reverse([?LF, ?CR | Header]) | Headers], Rest}};
83parse_headers(<<?LF, ?LF, Rest/binary>>, Header, Headers) ->
84    {ok, {[lists:reverse([?LF | Header]) | Headers], Rest}};
85parse_headers(<<?CR, ?LF, Rest/binary>>, Header, Headers) ->
86    parse_headers(Rest, [], [lists:reverse([?LF, ?CR | Header]) | Headers]);
87parse_headers(<<?LF, Rest/binary>>, Header, Headers) ->
88    parse_headers(Rest, [], [lists:reverse([?LF | Header]) | Headers]);
89parse_headers(<<Octet, Rest/binary>>, Header, Headers) ->
90    parse_headers(Rest, [Octet | Header], Headers).
91
92handle_headers([], HTTPHeaders, Status) ->
93    {ok, HTTPHeaders, Status};
94
95handle_headers([CGIHeader | CGIHeaders], HTTPHeaders, Status) ->
96
97    {FieldName, FieldValue} = httpd_response:split_header(CGIHeader, []),
98
99    case FieldName of
100	"content-type" ->
101	    handle_headers(CGIHeaders,
102			   [{FieldName, FieldValue} | HTTPHeaders],
103			   Status);
104	"location" ->
105	    case http_request:is_absolut_uri(FieldValue) of
106		true ->
107		    handle_headers(CGIHeaders,
108				       [{FieldName, FieldValue} |
109					HTTPHeaders], {302, "Redirect"});
110		false ->
111		    {proceed, FieldValue}
112	    end;
113	"status" ->
114	    CodePhrase =
115		case httpd_util:split(FieldValue," ",2) of
116		    {ok,[Code, Phrase]} ->
117			{list_to_integer(Code), Phrase};
118		    _ ->
119			{200, "OK"}
120		end,
121	    handle_headers(CGIHeaders, HTTPHeaders, CodePhrase);
122	_ -> %% Extension headers
123	    handle_headers(CGIHeaders,
124			   [{FieldName, FieldValue} | HTTPHeaders], Status)
125    end.
126
127