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"""HTML Diff: http://www.aaronsw.com/2002/diff
Rough code, badly documented. Send me comments and patches."""
__author__ = 'Aaron Swartz <me@aaronsw.com>'
__copyright__ = '(C) 2003 Aaron Swartz. GNU GPL 2.'
__version__ = '0.22'
import difflib, string
def isTag(x): return x[0] == "<" and x[-1] == ">"
def textDiff(a, b,
ins_start='<ins>', ins_end = '</ins>',
del_start='<del>', del_end='</del>'
):
"""Takes in strings a and b and returns a human-readable HTML diff."""
out = []
a, b = html2list(a), html2list(b)
s = difflib.SequenceMatcher(None, a, b)
for e in s.get_opcodes():
if e[0] == "replace":
# @@ need to do something more complicated here
# call textDiff but not for html, but for some html... ugh
# gonna cop-out for now
out.append(del_start + ''.join(a[e[1]:e[2]]) +
del_end + ins_start + ''.join(b[e[3]:e[4]])+ ins_end
)
elif e[0] == "delete":
out.append(del_start + ''.join(a[e[1]:e[2]]) + del_end)
elif e[0] == "insert":
out.append(ins_start + ''.join(b[e[3]:e[4]]) + ins_end)
elif e[0] == "equal":
out.append(''.join(b[e[3]:e[4]]))
else:
raise "Um, something's broken. I didn't expect a '" + `e[0]` + "'."
return ''.join(out)
def html2list(x, b=0):
mode = 'char'
cur = ''
out = []
for c in x:
if mode == 'tag':
if c == '>':
if b:
cur += ']'
else:
cur += c
out.append(cur)
cur = ''
mode = 'char'
else: cur += c
elif mode == 'char':
if c == '<':
out.append(cur)
if b:
cur = '['
else:
cur = c
mode = 'tag'
elif c in string.whitespace:
out.append(cur+c);
cur = ''
else:
cur += c
out.append(cur)
return filter(lambda x: x is not '', out)
if __name__ == '__main__':
import sys
try:
a, b = sys.argv[1:3]
except ValueError:
print "htmldiff: highlight the differences between two html files"
print "usage: " + sys.argv[0] + " a b"
sys.exit(1)
print textDiff(open(a).read(), open(b).read())
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