def request_fingerprint(request, include_headers=None):
include_headers = tuple(to_bytes(h.lower())
for h in sorted(include_headers))
cache = _fingerprint_cache.setdefault(request, {})
if include_headers not in cache:
fp.update(to_bytes(request.method))
fp.update(to_bytes(canonicalize_url(request.url)))
fp.update(request.body or b'')
for hdr in include_headers:
if hdr in request.headers:
for v in request.headers.getlist(hdr):
cache[include_headers] = fp.hexdigest()
return cache[include_headers]