
(********************************************************************)
(*                                                                  *)
(*  cgi.s7i       Support for the Common Gateway Interface          *)
(*  Copyright (C) 2008  Thomas Mertes                               *)
(*                                                                  *)
(*  This file is part of the Seed7 Runtime Library.                 *)
(*                                                                  *)
(*  The Seed7 Runtime Library is free software; you can             *)
(*  redistribute it and/or modify it under the terms of the GNU     *)
(*  Lesser General Public License as published by the Free Software *)
(*  Foundation; either version 2.1 of the License, or (at your      *)
(*  option) any later version.                                      *)
(*                                                                  *)
(*  The Seed7 Runtime Library is distributed in the hope that it    *)
(*  will be useful, but WITHOUT ANY WARRANTY; without even the      *)
(*  implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR *)
(*  PURPOSE.  See the GNU Lesser General Public License for more    *)
(*  details.                                                        *)
(*                                                                  *)
(*  You should have received a copy of the GNU Lesser General       *)
(*  Public License along with this program; if not, write to the    *)
(*  Free Software Foundation, Inc., 51 Franklin Street,             *)
(*  Fifth Floor, Boston, MA  02110-1301, USA.                       *)
(*                                                                  *)
(********************************************************************)


include "chartype.s7i";
include "file.s7i";
include "unicode.s7i";
include "encoding.s7i";


(**
 *  Read the CGI parameters from the given ''paramStri''.
 *  The parameter ''paramStri'' is assumed to consist of of elements
 *  separated with ampersands. Individual elements can have the
 *  form name=value or just name without = sign (in this case value
 *  is assumed to be ""). Name and value may be percent-encoded.
 *  Both are decoded and afterwards possible UTF-8 encodings are
 *  also decoded. The final values are entered into the hash table.
 *  A CGI script can use the environment variable QUERY_STRING
 *  as actual parameter for ''paramStri''. Web servers usually assign
 *  the URL part after the '?' character to QUERY_STRING.
 *  @param paramStri Percent encoded query string.
 *  @return a hash table containing CGI parameters as key, value pairs.
 *)
const func hash [string] string: getCgiParameters (in string: paramStri) is func
  result
    var hash [string] string: cgiParameters is (hash [string] string).value;
  local
    var array string: paramArray is 0 times "";
    var string: element is "";
    var integer: pos is 0;
    var string: name is "";
    var string: value is "";
  begin
    paramArray := split(paramStri, '&');
    for element range paramArray do
      pos := pos(element, '=');
      if pos <> 0 then
        name := element[.. pred(pos)];
        value := element[succ(pos) ..];
        value := fromUrlEncoded(value);
        block
          value := utf8ToStri(value);
        exception
          catch RANGE_ERROR:
            noop;
        end block;
      else
        name := element;
        value := "";
      end if;
      name := fromUrlEncoded(name);
      block
        name := utf8ToStri(name);
      exception
        catch RANGE_ERROR:
          noop;
      end block;
      cgiParameters @:= [name] value;
    end for;
  end func;


(**
 *  Read the CGI parameters from the given file ''inFile''.
 *  The standard input file IN can be used as actual parameter for
 *  ''inFile''.
 *  @return a hash table containing CGI parameters as key, value pairs.
 *)
const func hash [string] string: getCgiParameters (inout file: inFile) is func
  result
    var hash [string] string: cgiParameters is (hash [string] string).value;
  local
    var string: cgiParamLine is "";
  begin
    cgiParamLine := getln(inFile);
    block
      cgiParamLine := utf8ToStri(cgiParamLine);
    exception
      catch RANGE_ERROR:
        noop;
    end block;
    cgiParameters := getCgiParameters(cgiParamLine);
  end func;
