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I have a script that I have written that I would like to use whenever I click on a mailto: link. Which means I need to select it as the default Mail handler in my default applications.

But how do I register a mailto handler so that I can select it in the default applications?

Using Ubuntu 18.04, not virtualized.

I am not using a specific mail application, I am trying to write a script that will process the mailto links for me (for example, using different mail clients for different destination domains), but I need to convince Ubuntu that this script is an option for a default mail application

K7AAY
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David Ljung Madison Stellar
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1 Answers1

0

Thanks to @danzel, I found the answer was indeed to use a .desktop file.

So I created a simple script that allows you to specify a set of different mailers - I use my work email (Outlook for web), my personal email (via ssh) and sometimes gmail.

Here's the code:

#!/usr/bin/ruby
# 1) Put "mailto.desktop" in /usr/share/applications
# 2) sudo update-desktop-database
# 3) System Prefs -> Details -> Default Applications

require 'uri'

# %SUBJECT% decoded subject, i.e.:  "Hey guys!"
# %subject% encoded subject, i.e.:  "Hey%20guys%21"
# Same for %to% and %body%
# Also %mailto% for initial value of "mailto:..."
MAILERS = {
    'Home' => ['ssh','-t','my-home-server.com','elm','-s','"%subject%"','%to%'],
    'Work' => ['browser','https://outlook.office.com/?path=/mail/action/compose&to=%mailto%'],
    'Gmail' => ['browser','https://mail.google.com/mail/u/0/?&view=cm&fs=1&to=%TO%&su=%SUBJECT%&body=%BODY%']
}

def fatal(title,message)
    system('zenity','--width','400','--height','250','--error','--title',title,'--text',message)
    exit -1
end

def clean(str)
    #'"'+str+'"'
    str.sub(/"/,'')
end

#########################
# Figure out mailto:
#########################
mailtoStr=ARGV.join('')
mailtoStr.sub!(/^mailto:/,'')
mailto = mailtoStr.split(/[\?\&]/)
mailtoStr.sub!(/\?/,'&')  # Outlook is confused if you use:  'mailto:addr@some.com?subject=...' instead of '..&subject..'
mailHash = Hash.new
mailto.each { |m|
    m.match(/^([^=]+)=(.*)/m)
    key,val = $1,$2
    key,val = 'to',m unless key
    mailHash[key.upcase] = clean(val)
    mailHash[key.downcase] = clean(URI.decode(val))
}
fatal("No 'to' specified",'Need to specify an address in the mailto') unless mailHash['to']

FIELDS = %w(to body subject mailto)
def sendInfo(mailHash,mailtoStr,field)
    return '' unless field
    return mailtoStr if field=='mailto'
    return '%'+field+'%' unless FIELDS.index(field.downcase)
    mailHash[field] || ''
end

#########################
# Pick mailer
#########################
mailer = 'Work' if mailHash['to'].match(/@my-work-domain.com$/)
mailer ||= `zenity --width 400 --height 250 --title "Mailer select" --text "Choose mailer for #{mailHash['to']}:" --list --column "Mailer" #{MAILERS.keys.map { |m| '"'+m+'"' }.join(' ')}`
mailer.chomp!

fatal('Unknown Mailer',"Don't know mailer selection #{mailer} or no mailer selected") unless MAILERS[mailer]

cmd = MAILERS[mailer]
cmd.each { |c|
    c.gsub!(/%([^%]+)%/) { sendInfo(mailHash,mailtoStr,$1) }
}
#p cmd
system(*cmd)
# Sometimes ssh is broken on my system...
system(*cmd) if cmd[0].match(/ssh/) && $?.exitstatus!=0

And the mailto.desktop which goes in /usr/share/applications:

[Desktop Entry]
Encoding=UTF-8
Name=Custom mailto Mail Handler
Comment=Handle mailto links
GenericName=Mail Client
Keywords=Email;E-mail
Exec=/home/dave/bin/mailto %u
Terminal=true
X-MultipleArgs=false
Type=Application
Icon=mail-send
Categories=Application;Network;Email;
MimeType=x-scheme-handler/mailto;application/x-xpinstall;
StartupNotify=true

I have "Terminal=true" because I use ssh, and that's where the ssh window goes, otherwise the terminal window disappears pretty quick. If you don't use any terminal based mailers you can set that to false.

David Ljung Madison Stellar
  • 494