gistfile1.txt

import base64
from diffmatchpatch import diff_match_patch

DMP = diff_match_patch()

def diff(a, b):
    a = base64.b64encode(a.encode('utf-8'))
    b = base64.b64encode(b.encode('utf-8'))
    diffs = DMP.diff_main(a, b)
    if len(diffs) > 2:
        DMP.diff_cleanupEfficiency(diffs)
    if len(diffs) > 0:
        delta = DMP.diff_toDelta(diffs)
        return delta

def patch(a, d):
    a = base64.b64encode(a.encode('utf-8'))
    diffs = DMP.diff_fromDelta(a, d)
    patches = DMP.patch_make(a, diffs)
    result = DMP.patch_apply(patches, a)
    return base64.b64decode(result[0]).decode('utf-8')


client_a = u'\ud83d\udc7f 1'
client_b = u'\ud83d\udc7f 2'
client_diff = diff(client_a, client_b)


server_a = u'\U0001f47f 1'
server_b = u'\U0001f47f 2'
server_diff = diff(server_a, server_b)

print client_diff == server_diff
print repr(patch(server_a, client_diff))