#!/usr/bin/perl -- -*- C -*-
# Perl Routines to Manipulate CGI input
# S.E.Brenner@bioc.cam.ac.uk
#
# Copyright 1994 Steven E. Brenner  
# Unpublished work.
# Permission granted to use and modify this library so long as the
# copyright above is maintained, modifications are documented, and
# credit is given for any use of the library.
#
# Thanks are due to many people for reporting bugs and suggestions
# especially Meng Weng Wong, Maki Watanabe, Bo Frese Rasmussen,
# Andrew Dalke, Mark-Jason Dominus and Dave Dittrich.
# For more information, see:
#     http://www.bio.cam.ac.uk/web/form.html       
#     http://www.seas.upenn.edu/~mengwong/forms/   
# Minimalist http form and script (http://www.bio.cam.ac.uk/web/minimal.cgi):
#
# require "cgi-lib.pl";
# if (&ReadParse(*input)) {
#    print &PrintHeader, &PrintVariables(%input);
# } else {
#   print &PrintHeader,'<form><input type="submit">Data: <input name="myfield">';
#}
# ReadParse
# Reads in GET or POST data, converts it to unescaped text, and puts
# one key=value in each member of the list "@in"
# Also creates key/value pairs in %in, using '\0' to separate multiple
# selections
# Returns TRUE if there was input, FALSE if there was no input 
# UNDEF may be used in the future to indicate some failure.
# Now that cgi scripts can be put in the normal file space, it is useful
# to combine both the form and the script in one place.  If no parameters
# are given (i.e., ReadParse returns FALSE), then a form could be output.
# If a variable-glob parameter (e.g., *cgi_input) is passed to ReadParse,
# information is stored there, rather than in $in, @in, and %in.
#
# $FreeBSD: www/en/cgi/cgi-lib.pl,v 1.4 2001/07/13 12:49:08 dd Exp $
#

sub ReadParse {
  local (*in) = @_ if @_;
  local ($i, $key, $val);
  # Read in text
  if (&MethGet) {
    $in = $ENV{'QUERY_STRING'};
  } elsif ($ENV{'REQUEST_METHOD'} eq "POST") {
    read(STDIN,$in,$ENV{'CONTENT_LENGTH'});
  }
  @in = split(/&/,$in);
  foreach $i (0 .. $#in) {
    # Convert plus's to spaces
    $in[$i] =~ s/\+/ /g;
    # Split into key and value.  
    ($key, $val) = split(/=/,$in[$i],2); # splits on the first =.
    # Convert %XX from hex numbers to alphanumeric
    $key =~ s/%(..)/pack("c",hex($1))/ge;
    $key =~ tr/[^A-Za-z0-9\-\_\$\+\=\~\.\,]//;		# allow only safe chars
    $val =~ s/%(..)/pack("c",hex($1))/ge;
    $val =~ tr/[^A-Za-z0-9\-\_\$\+\=\~\.\,]//;		# allow only safe chars
    # Associate key and value
    $in{$key} .= "\0" if (defined($in{$key})); # \0 is the multiple separator
    $in{$key} .= $val;
  }
  return length($in); 
}
# PrintHeader
# Returns the magic line which tells WWW that we're an HTML document
sub PrintHeader {
  return "Content-type: text/html\n\n";
}
# MethGet
# Return true if this cgi call was using the GET request, false otherwise
sub MethGet {
  return ($ENV{'REQUEST_METHOD'} eq "GET");
}
# MyURL
# Returns a URL to the script
sub MyURL  {
  return  'http://' . $ENV{'SERVER_NAME'} .  $ENV{'SCRIPT_NAME'};
}
# CgiError
# Prints out an error message which containes appropriate headers,
# markup, etcetera.
# Parameters:
#  If no parameters, gives a generic error message
#  Otherwise, the first parameter will be the title and the rest will 
#  be given as different paragraphs of the body
sub CgiError {
  local (@msg) = @_;
  local ($i,$name);
  if (!@msg) {
    $name = &MyURL;
    @msg = ("Error: script $name encountered fatal error");
  };
  print &PrintHeader;
  print "<html><head><title>$msg[0]</title></head>\n";
  print "<body><h1>$msg[0]</h1>\n";
  foreach $i (1 .. $#msg) {
    print "<p>$msg[$i]</p>\n";
  }
  print "</body></html>\n";
}
# PrintVariables
# Nicely formats variables in an associative array passed as a parameter
# And returns the HTML string.
sub PrintVariables {
  local (%in) = @_;
  local ($old, $out, $output);
  $old = $*;  $* =1;
  $output .=  "<DL COMPACT>";
  foreach $key (sort keys(%in)) {
    foreach (split("\0", $in{$key})) {
      ($out = $_) =~ s/\n/<BR>/g;
      $output .=  "<DT><B>$key</B><DD><I>$out</I><BR>";
    }
  }
  $output .=  "</DL>";
  $* = $old;
  return $output;
}
1;
