diff --git a/progit/lib.py b/progit/lib.py
index 9159f9d..a8e0aec 100644
--- a/progit/lib.py
+++ b/progit/lib.py
@@ -9,6 +9,7 @@
 """
 
 
+import datetime
 import json
 import os
 import shutil
@@ -46,6 +47,41 @@ def create_session(db_url, debug=False, pool_recycle=3600):
     return scopedsession
 
 
+def commit_to_patch(repo_obj, commit):
+    ''' For a given commit (PyGit2 commit object) of a specified git repo,
+    returns a string representation of the changes the commit did in a
+    format that allows it to be used as patch.
+    '''
+    if commit.parents:
+        diff = commit.tree.diff_to_tree()
+
+        parent = repo_obj.revparse_single('%s^' % commit.oid.hex)
+        diff = repo_obj.diff(parent, commit)
+    else:
+        # First commit in the repo
+        diff = commit.tree.diff_to_tree(swap=True)
+
+    patch = """From %(commit)s
+From: %(author_name)s <%(author_email)s>
+Date: %(date)s
+
+%(msg)s
+
+%(patch)s
+""" % (
+        {
+            'commit': commit.oid.hex,
+            'author_name': commit.author.name,
+            'author_email': commit.author.email,
+            'date': datetime.datetime.utcfromtimestamp(
+                commit.commit_time).strftime('%b %d %Y %H:%M:%S +0000'),
+            'msg': commit.message,
+            'patch': diff.patch,
+        }
+    )
+    return patch
+
+
 def get_user(session, username):
     ''' Return the user corresponding to this username, or None. '''
     user = session.query(