(feat)(falcon/routing) Allow numbers in template fields

[BenjamenMeyer]

Allow URI template fields to contain numbers so long as the field name does not start
with a numeral.

Example: "test123" is valid, while "123test" is not

Supports Issue #35

Note: '\w' = [0-9A-Za-z_]

[kgriffs]

#484 should address this. Can you give it a try?

[BenjamenMeyer]

@kgriffs Sorry, I just noticed your comment.

I checked out PR #484 (as requested) and actually merged master into this PR, namely so that I could just check the tests more carefully. Since he already had the negative test (

falcon/tests/test_uri_templates.py

Line 50 in 4a5e5b1

def test_field_name_cannot_start_with_digit(self):

) I did this primarily to check my positive test which passed.

The PR seems to cover my positive test in the complex test (

falcon/tests/test_default_router.py

Line 64 in 4a5e5b1

def test_complex(self):

), just a little more indirect. The merge basically reduces this PR to adding the couple tests more explicitly.

falcon/falcon/routing/compiled.py

Line 183 in 4a5e5b1

matches = list(re.finditer('{([-_a-zA-Z0-9]+)}', seg))

seems to do what my regex changes does, with the negative prevented by

falcon/falcon/routing/compiled.py

Line 67 in 4a5e5b1

if re.search('{\d', uri_template):

. I think the negative test has the potential to be bypassed, but if someone is doing that then the bug is in their code, not Falcon's.

In the end, what I reported looks to be fixed. I'll leave it to you whether to accept my extra couple tests.
If you want them, then merge. If not, you can close the PR. I'm happy with the result.

[kgriffs]

Merged manually. Thanks @BenjamenMeyer !