Change request handling to use split instead of regular expressions.

[cthulahoops]

The regular expression fails with a stack overflow for paths of
more than 135 characters. The split also appears to be much faster.

Failing parse:

>>> import re
>>> _REQUEST_RE = re.compile(r"(\S+)\s+(\S+)\s")
>>> _REQUEST_RE.match("GET /" + ("a" * 135) + " whatev")
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
RuntimeError: maximum recursion depth exceeded

Co-authored-by: Shae Erisson shae@scannedinavian.com

[dhalbert]

I don't get the stack overflow error, testing on a random board (nrRF 52840). What board are you testing this on?

[shapr]

I don't get the stack overflow error, testing on a random board (nrRF 52840). What board are you testing this on?

This fails on the AdaFruit FunHouse running Circuit Python 7.2.5

>>> import re
>>> _REQUEST_RE = re.compile(r"(\S+)\s+(\S+)\s")
>>> _REQUEST_RE.match("GET /" + ("a" * 135) + " whatev")
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
RuntimeError: maximum recursion depth exceeded
>>> _REQUEST_RE.match("GET /" + ("a" * 134) + " whatev")
<match num=3>

[shapr]

I don't get the stack overflow error, testing on a random board (nrRF 52840). What board are you testing this on?

Same thing on a MagTag with CircuitPython 7.2.5

Adafruit CircuitPython 7.2.5 on 2022-04-06; Adafruit MagTag with ESP32S2
>>> import re
>>> _REQUEST_RE = re.compile(r"(\S+)\s+(\S+)\s")
>>> _REQUEST_RE.match("GET /" + ("a" * 135) + " whatev")
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
RuntimeError: maximum recursion depth exceeded
>>> _REQUEST_RE.match("GET /" + ("a" * 134) + " whatev")
<match num=3>

[dhalbert]

I think there is a stack depth issue on ESP32-nn. That is a separate core CircuitPython issue. But I'll review this for its own sake.

[dhalbert]

Thanks for this. I think using the regular expression would generate less garbage, but if it's noticeably faster, that's fine too.

[dhalbert]

Thanks!