Url handler for telnet and ssh schemas

[Eric Moret]

Could you please review this email and answer questions listed below.

Thanks,
__
Eric

On Fri, Sep 17, 2010 at 7:22 PM, Eric Moret <eric.moret at gmail.com> wrote:
> Hi fedora-devel,
>
> I would like to contribute a piece of bash code that handles url in
> gnome for ssh and telnet schemas. The idea being that whenever a user
> clicks a link the proper client opens up in the default terminal
> window configured in the user's "Preferred Applications" dialog.
> examples of links:
> telnet://my.telnet.server/
> ssh://root@my.home.server:2222/
>
> I am not quite sure what upstream should look like for such a script.
> I took some of my code from launchmail which is a somewhat similar
> script for email but has no upstream (that I can tell). The xdg-open
> script from the portland/xdg-utils package is a wrapper that only
> calls the corresponding Desktop startup tool. In the case of gnome it
> calls gnome-open with the url passed to xdg-open. Only issue is that
> gnome-open does not support telnet or ssh.
>
> I appreciate any direct feedback on the below script and suggestions
> for upstream location.
> __
> Eric
>
>
> $ cat terminal-url-handler
> #!/bin/bash
>
> # to enable URL handling in FF, open the about:config page and add a new string:
> # network.protocol-handler.app.telnet with value:
> /path/to/handler/terminal-url-handler
> # then add 2 new boolean:
> # network.protocol-handler.external.telnet and set to true
> # network.protocol-handler.external.ssh and set to true
> # last, select "always ask" for content type telnet in Firefox
> Preferences | Applications dialog
> # the first time you use the handler manually select the script file
> and check the remember option
> #
> # to enable this handler in gnome make sure you create the following
> values in gconf:
> # gconftool-2 -s /desktop/gnome/url-handlers/ssh/command
> '/path/to/terminal-url-handler %s' --type String
> # gconftool-2 -s /desktop/gnome/url-handlers/ssh/enabled --type Boolean true
> # gconftool-2 -s /desktop/gnome/url-handlers/ssh/needs_terminal --type
> Boolean false
> # gconftool-2 -s /desktop/gnome/url-handlers/telnet/command
> '/path/to/terminal-url-handler %s' --type String
> # gconftool-2 -s /desktop/gnome/url-handlers/telnet/enabled --type Boolean true
> # gconftool-2 -s /desktop/gnome/url-handlers/telnet/needs_terminal
> --type Boolean false
>
> #
> # URI parsing function
> # taken from http://valeriu.palos.ro/537/uri-parsing-using-bash-built-in-features/
> #
> # The function creates global variables with the parsed results.
> # It returns 0 if parsing was successful or non-zero otherwise.
> #
> # [schema://][user[:password]@]host[:port][/path][?[param=value]...][#fragment]
> #
> uri_parser () {
>   # uri capture
>   uri="$@"
>
>   # safe escaping
>   uri="${uri//\`/%60}"
>   uri="${uri//\"/%22}"
>
>   # top level parsing
>   pattern='^(([a-z]{3,6})://)?((([^:\/]+)(:([^@\/]*))?@)?([^:\/?]+)(:([0-9]+))?)(\/[^?]*)?(\?[^#]*)?(#.*)?$'
>   [[ "$uri" =~ $pattern ]] || return 1;
>
>   # component extraction
>   uri=${BASH_REMATCH[0]}
>   uri_schema=${BASH_REMATCH[2]}
>   uri_address=${BASH_REMATCH[3]}
>   uri_user=${BASH_REMATCH[5]}
>   uri_password=${BASH_REMATCH[7]}
>   uri_host=${BASH_REMATCH[8]}
>   uri_port=${BASH_REMATCH[10]}
>   uri_path=${BASH_REMATCH[11]}
>   uri_query=${BASH_REMATCH[12]}
>   uri_fragment=${BASH_REMATCH[13]}
>
>   # path parsing
>   count=0
>   path="$uri_path"
>   pattern='^/+([^/]+)'
>   while [[ $path =~ $pattern ]]; do
>     eval "uri_parts[$count]=\"${BASH_REMATCH[1]}\""
>     path="${path:${#BASH_REMATCH[0]}}"
>     let count++
>   done
>
>   # query parsing
>   count=0
>   query="$uri_query"
>   pattern='^[?&]+([^= ]+)(=([^&]*))?'
>   while [[ $query =~ $pattern ]]; do
>     eval "uri_args[$count]=\"${BASH_REMATCH[1]}\""
>     eval "uri_arg_${BASH_REMATCH[1]}=\"${BASH_REMATCH[3]}\""
>     query="${query:${#BASH_REMATCH[0]}}"
>     let count++
>   done
>
>   # return success
>   return 0
> }
>
> error_dialog () {
>   echo "$1"
>   if [ -x /usr/bin/zenity ]; then
>     /usr/bin/zenity --error --text="$1"
>   else
>     xmessage "$1"
>   fi
> }
>
> sanity_check () {
>   unset INVALID
>   echo "$1" | grep -q "terminal-url-handler" && INVALID="yes"
>   echo "$1" | grep -q "gnome-open" && INVALID="yes"
>   if [ "$INVALID" == "yes" ]; then
>     error_dialog "Error: $1 is an invalid terminal.  Please reconfigure."
>     [ -x /usr/bin/gnome-default-applications-properties ] && exec
> /usr/bin/gnome-default-applications-properties
>     exit 1
>   fi
> }
>
> exists () {
>   which "${1%% *}" 2> /dev/null > /dev/null
>   return $?
> }
>
> if [ $# != 1 ]; then
>   error_dialog "Usage: $0 &lt;url&gt;"
>   exit 1
> fi
>
> uri_parser $1
> if [ "$?" != 0 ]; then
>   error_dialog "Error: Invalid URL"
>   exit 1
> fi
>
> if [ "$uri_schema" == 'telnet' ]; then
>   CLI="$uri_schema $uri_host $uri_port"
> elif [ "$uri_schema" == 'ssh' ]; then
>   CLI="$uri_schema -p ${uri_port:-22} ${uri_user:-$USER}@$uri_host"
> else
>   error_dialog "Error: telnet and ssh are the only supported url schemas"
>   exit 1
> fi
>
> # Attempt to use GNOME Preferred Terminal
> if [ -x /usr/bin/gconftool-2 -a -x
> /usr/bin/gnome-default-applications-properties ]; then
>   # Pull key from gconf, trim leading & trailing spaces
>   PREFTERM=$(gconftool-2 -g /desktop/gnome/applications/terminal/exec
> 2>/dev/null | sed -e 's/^\ *//; s/\ *$//')
>   TERMARGS=$(gconftool-2 -g
> /desktop/gnome/applications/terminal/exec_arg 2>/dev/null | sed -e
> 's/^\ *//; s/\ *$//')
>
>   # Remove arguments
>   PREFTERM="`echo $PREFTERM | cut -f1 -d" "`"
>
>   # sanity check (prevent infinite loops)
>   sanity_check "$PREFTERM"
>
>   if [ ! -z $DISPLAY ] &&  [ -x /usr/bin/gnome-open ]; then
>     if ! exists "$PREFTERM"; then
>       error_dialog "Error: The terminal $PREFTERM does not exist.
> Please reconfigure."
>       [ -x /usr/bin/gnome-default-applications-properties ] && exec
> /usr/bin/gnome-default-applications-properties
>       exit 1
>     fi
>   fi
> else
>   TERMINALS="gnome-terminal konsole urxvt rxvt aterm xterm"
>   for PREFTERM in $TERMINALS; do
>     exists "$terminal" && break
>   done
> fi
>
> exec $PREFTERM $TERMARGS $CLI
>