Default (Linux).sublime-keymap

[
  { "keys": ["ctrl+shift+x"], "command": "tidy_xml" },
  { "keys": ["ctrl+shift+j"], "command": "prettify_json" }
]

prettify_json.py

import sublime, sublime_plugin, subprocess

class PrettifyJsonCommand(sublime_plugin.TextCommand):
  def run(self, edit):
    # requires rubygems json: 'gem install json'
    command = '/local/rvm/bin/rvm exec prettify_json.rb'

    # help from http://www.sublimetext.com/forum/viewtopic.php?f=2&p=12451
    p = subprocess.Popen(command, bufsize=-1, stdout=subprocess.PIPE, stderr=subprocess.PIPE, stdin=subprocess.PIPE, shell=True)
    result, err = p.communicate(self.view.substr(self.view.sel()[0]).encode('utf-8'))

    self.view.replace(edit, self.view.sel()[0], result.decode('utf-8'))

tidy_xml.py

import sublime, sublime_plugin, subprocess

class TidyXmlCommand(sublime_plugin.TextCommand):
  def run(self, edit):
    command = 'tidy -xml -i -utf8 -w -q'

    # help from http://www.sublimetext.com/forum/viewtopic.php?f=2&p=12451
    p = subprocess.Popen(command, bufsize=-1, stdout=subprocess.PIPE, stderr=subprocess.PIPE, stdin=subprocess.PIPE, shell=True)
    result, err = p.communicate(self.view.substr(self.view.sel()[0]).encode('utf-8'))

    if err != "":
      self.view.set_status('tidyxml', "tidyxml: "+err)
      sublime.set_timeout(self.clear,10000)
    else:
      self.view.replace(edit, self.view.sel()[0], result.decode('utf-8'))
    

  def clear(self):
    self.view.erase_status('tidyxml')