Complete instructions for getting xmllint to work with Sublime Text 2 and Windows.

Instructions.txt

1)  Download XMLLint for Windows here:
    https://code.google.com/p/xmllint/downloads/list
    
2)  Choose the xmllint-1.0.exe version and save somewhere in your Windows path (such as your user path).

3)  Rename the file to: xmllint.exe    (remove the -1.0)

4)  Open Sublime Text 2

5)  Click Preferences -> Browse Packages  (opens up your Packages folder in Windows Explorer).

6)  Open up the "User" folder in your Packages folder.

7)  Create a file named:  tidy_xml_lint.py

8)  Open that file in, well, Sublime Text 2 of course!

9)  Paste the contents of the "tidy_xml_lint.py" gist on this page.

10) Save the file and restart Sublime Text 2.  Sometimes, you don't have to restart but I find it helps most of the time.

11) Click Preferences -> Keybindings - User

12) Alter that file so that it contains the "Keybindings - User" gist on this page.

13) Be sure the change the keybindings to what you prefer.  This example uses ALT-SHIFT-X.

14) Save the file.

15) Go back to your Packages -> User folder in Windows Explorer.

16) Create (or open if it exists) a file called:  Main.sublime-menu

17) Open that file in Sublime Text 2

18) Alter the file so that it includes the "Main.sublime-menu" gist on this page.

19) Save and relaunch Sublime Text 2 for good measure.

20) Enjoy.

You can now press "ALT-SHIFT-X" to format either a selection of text or the entire document if nothing is selected.

Keybindings - User.txt

[
    { "keys": ["alt+shift+x"], "command": "tidy_xml_lint" }
]

Main.sublime-menu

[
    {
        "caption": "Selection",
        "children": [
            {
                "caption": "Format",
                "children": [
                    {
                        "caption": "Tidy with XML Lint",
                        "command": "tidy_xml_lint"
                    }
                ],
                "id": "format"
            }
        ],
        "id": "selection"
    }
]

tidy_xml_lint.py

import sublime, sublime_plugin, subprocess
 
class TidyXmlLintCommand(sublime_plugin.TextCommand):
  def run(self, edit):
    command = "xmllint -format -encode utf-8 -"
 
    # help from http://www.sublimetext.com/forum/viewtopic.php?f=2&p=12451
    if self.view.sel()[0].empty():
      xmlRegion = sublime.Region(0, self.view.size())
    else:
      xmlRegion = self.view.sel()[0]
 
    p = subprocess.Popen(command, bufsize=-1, stdout=subprocess.PIPE, stderr=subprocess.PIPE, stdin=subprocess.PIPE, shell=True)
    result, err = p.communicate(self.view.substr(xmlRegion).encode('utf-8'))
 
    if err != b"":
      self.view.set_status('xmllint', "xmllint: " + err.decode("utf-8"))
      sublime.set_timeout(self.clear,10000)
    else:
      self.view.replace(edit, xmlRegion, result.decode('utf-8'))
      sublime.set_timeout(self.clear,0)
 
  def clear(self):
    self.view.erase_status('xmllint')