lynx-dev Perl script interface for composing mail to mailto links

[kweide]

> > mu%0d%0d
> > mu.
>
> Mad cow disease?  (OST, isn't it spelt "moo?")

Well, that was my first attempt at a minimal "mailto handler for lynx"
following Leonid's idea from
   Linkname: lynx-dev MAILTO internal page proposal - form with textarea
        URL: http://www.flora.org/lynx-dev/html/month021999/msg00469.html
I wrote that as a set of bash scripts, but it was so low for anything but
a couple of lines that I had to wait until the cows came home when sending
a message...

Se here is the Perl version.  If you see this message, that's proof
that it worked.
(I ceated with the quoted text at the beginning - that's manually cut-n-
pasted.  This method can't include original message - same as in the
the other recent proposals.)

Whoever tries this, please report success or failure.

   Klaus

------------------------- mailto-form.pl -----------------------
#! /usr/bin/perl
# Some scripts for handling mailto URLs within lynx via an interactive form
#
# Warning: this is a quick demo, to show what kinds of things are possible
# by hooking some external commands into lynx.  Use at your own risk.
#
# Requirements:
#
# - Perl and CGI.pm.
# - A "sendmail" command for actually sending mail (if you need some
#   other interface, change the code below in sub sendit appropriately).
# - Lynx compiled with support for lynxcgi, that means EXEC_CGI must have
#   been defined at compilation, usually done with
#     ./configure --enable-cgi-links
# - Lynx must have support for CERN-style rules as of 2.8.3, which must
#   not have been disabled at compilation (it is enabled by default).
#
# Instructions:
# (This is for people without lynxcgi experience; if you are already
# use lynxcgi, you don't have to follow everything literally, use
# common sense for picking appropriate file locations in your situation.)
#
# - Make a subdirectory 'lynxcgi' under you home directory, i.e.
#      mkdir ~/lynxcgi
# - Put this script file mailto-form.pl there and make it executable.
# For example,
#      cp mailto-form.pl ~/lynxcgi
#      chmod a+x ~/lynxcgi/mailto-form.pl
# - Edit mailto-form.pl (THIS FILE), there are some strings that
#   that need to be changed, see ### Configurable variables ###
#   below.
# - Allow lynx to execute lynxcgi files in that directory, for example,
#   put in your lynx.cfg file:
#      TRUSTED_LYNXCGI:<tab>/home/myhomedir/lynxcgi/mailto-form.pl
#   where <tab> is a real TAB character and you have to put the real
#   location of your directory in place of "myhomedir", of course.
#   The '~' abbreviation cannot be used.
#   You could also just enable execution of all lynxcgi scripts, by
#   not having any TRUSTED_LYNXCGI options in lynx.cfg at all, but
#   that can't be recommended.
# - Tell lynx to actually use the lynxcgi scripts for mailto URLs.
#   There are two variants:
#   a) Redirect "mailto"
#   Requires patched lynx, currently not yet in the developent code.
#   Use the following two lines in the file that is configured as
#   RULESFILE in lynxcfg:
#      PermitRedirection mailto:*
#      Redirect mailto:* lynxcgi:/home/myhomedir/lynxcgi/address@hidden&to=*
#   You can also put them directly in lynx.cfg, prefixing each with
#   "RULE:".  Replace ""myhomedir", "myname", and "myhost" with your
#   correct values, of course.
#   b) Redirect "xmailto"
#   Requires defining a fake proxy before starting lynx, like
#      export xmailto_proxy=dummy  # or for csh: setenv xmailto_proxy dummy
#   Requires that you change "mailto" to "xmailto" each time you want
#   to activate a mailto link.  This can be done conveniently with
#   a few keys: 'E', ^A, 'x', Enter.
#   Use the following two lines in the file that is configured as
#   RULESFILE in lynxcfg:
#      PermitRedirection xmailto:*
#      Redirect xmailto:* lynxcgi:/home/myhomedir/lynxcgi/address@hidden&to=*
#   You can also put them directly in lynx.cfg, prefixing each with
#   "RULE:".  Replace ""myhomedir", "myname", and "myhost" with your
#   correct values, of course.
#
# Limitations:
#
# - Only applies to mailto URLs that appear as links or are entered at
#   a 'g'oto prompt.  Does not apply to other ways of sending mail, like
#   the 'c' (COMMENT) key, mailto as a FORM action, or mailing a file
#   from the 'P'rinting Options screen.
# - Nothing is done for charset labelling, content-transfer-encoding
#   of non-ASCII characters, and other MIME niceties.
#
# Klaus Weide 20000712

########################################################################
########## Configurable variables ######################################

$SENDMAIL = '/usr/sbin/sendmail';
#                                   The location of your sendmail binary
$SELFURL = 'lynxcgi:/home/lynxdev/lynxcgi/mailto-form.pl';
#                                   Where this script lives in URL space
$SEND_TOKEN = '/vJhOp6eQ';
#                           When found in the PATH_INFO part of the URL,
#                           this causes the script to actually send mail
#                           by calling $SENDMAIL instead of just throwing
#                           up a form.  CHANGE IT!  And don't tell anyone!
#                           Treat it like a password.
#                           Must start with '/', probably should have only
#                           alphanumeric ASCII characters.

## Also, make sure the first line of this script points
## to your PERL binary

########## Nothing else to change - I hope #############################
########################################################################

use CGI qw/-no_debug :standard/;

$|=1;

# Upcase first character
sub ucfirst {
    s/^./\U$1/;
}
# If there are mutiple occurrences of the same thing, how to join them
# into one string
%joiner = (from => ', ',
           to => ', ',
           cc => ', ',
           subject => '; ',
           body => "\n\n"
           );
sub joiner {
    my ($key) = @_;
    if ($joiner{$key}) {
        $joiner{$key};
    } else {
        " ";
    }
}

# Here we check whether this script is called for actual sending, rather
# than form generation.  If so, all the rest is handled by sub sendit, below.
$pathinfo = $ENV{'PATH_INFO'};
if ($pathinfo eq $SEND_TOKEN) {
    print header('text/plain');
    sendit();
    exit;
}

print header;

$long_title = $ENV{'QUERY_STRING'};
$long_title =~ s/^from=([^&]*)\&to=//;
$long_title = "someone" unless $long_title;
$long_title = "Compose mail for $long_title";
if (length($long_title) > 72) {
    $title = substr($long_title,0,72) . "...";
} else {
    $title = $long_title;
}
$long_title =~ s/&/&amp;/g;
$long_title =~ s/</&lt;/g;
print
    start_html($title), "\n",
    h1($long_title), "\n",
    start_form(-method=>'GET', -action => $SELFURL . $SEND_TOKEN), "\n";

print "<TABLE>\n";
@fields = param();
foreach $key (@fields) {
    @vals = param($key);
    if (scalar(@vals) != 1) {
        print "multiple values " . scalar(@vals) ." for $key!\n";
        param($key, join (joiner($key), @vals));
    }
}
foreach $key (@fields) {
    $_ = lc($key);
    if ($_ ne $key) {
        print "noncanonical case for $key!\n";
        $val=param($key);
        Delete($key);
        if (!param($_)) {
            param($_, $val);
        } else {
            param($_, param($_) . joiner($_) . "$val");
        }
    }
}
foreach $key ('from', 'to', 'cc', 'subject') {
    print Tr,
    td(ucfirst($key) . ":"),
    td(textfield(-name=>$key,
                    -size=>60,
                    -default=>param($key))), "\n";
    Delete($key);
}

# Also pass on any unrecognized header fields that were specified.
# This may not be a good idea for general use!
# At least some dangerous header fields may have to be suppressed.
@keys = param();
if (scalar(@keys) > ((param('body')) ? 1 : 0)) {
    print "<TR><TD colspan=2><EM>Additional headers:</EM>\n";
    foreach $key (param()) {
        if ($key ne 'body') {
            print Tr,
            td(ucfirst($key) . ":"),
            td(textfield(-name=>$key,
                         -size=>60,
                         -default=>param($key))), "\n";
        }
    }
}
print "</TABLE>\n";
print textarea(-name=>'body',
               -default=>param('body')), "\n";
print "<PRE>\n\n</PRE>", "\n",
    submit(-value=>"Send the message"), "\n",
    endform, "\n";

print "\n";
exit;

# This is for header field values.
sub sanitize_field_value {
    my($val) = @_;
    $val =~ s/\0/./g;
    $val =~ s/\r\n/\n/g;
    $val =~ s/\r/\n/g;
    $val =~ s/\n*$//g;
    $val =~ s/\n+/\n/g;
    $val =~ s/\n(\S)/\n\t$1/g;
    $val;
}

sub sendit {
    open (MAIL, "| $SENDMAIL -t -oi -v") || die ("$0: Can't run sendmail: 
$!\n");
    @fields = param();
    foreach $key (@fields) {
        @vals = param($key);
        if (scalar(@vals) != 1) {
            print "multiple values " . scalar(@vals) ." for $key!\n";
            param($key, join (joiner($key), @vals));
        }
    }
    foreach $key (@fields) {
        if ($key ne 'body') {
            if ($key =~ /[^A-Za-z0-9_-]/) {
                print "$0: Ignoring malformed header field named '$key'!\n";
                next;
            }
            print MAIL ucfirst($key) . ": " .
                sanitize_field_value(param($key)) . "\n"
                or die ("$0: Feeding header to sendmail failed: $!\n");
        }
    }
    print MAIL "\n"
        or die ("$0: Ending header for sendmail failed: $!\n");
    print MAIL param('body'), "\n"
        or die ("$0: Feeding body to sendmail failed: $!\n");
    close(MAIL)
        or warn $! ? "Error closing pipe to sendmail: $!"
            : ($? & 127) ? ("Sendmail killed by signal " . ($? & 127) .
                            ($? & 127) ? ", core dumped" : "")
                : "Return value " . ($? >> 8) . " from sendmail";
}

; To UNSUBSCRIBE: Send "unsubscribe lynx-dev" to address@hidden