Add utility function with tests to pad datetime digits and validate

ipwb/replay.py

@@ -248,6 +248,11 @@ def resolveMemento(urir, datetime):
 
 @app.route('/memento/<regex("[0-9]{1,14}"):datetime>/<path:urir>')
 def showMemento(urir, datetime):
+    try:
+        datetime = ipwbUtils.padDigits14(datetime, validate=True)
+    except ValueError as e:
+        msg = 'Expected a 4-14 digits valid datetime: {}'.format(datetime)
+        return Response(msg, status=400)
     resolvedMemento = resolveMemento(urir, datetime)
 
     # resolved to a 404, flask Response object returned instead of tuple

ipwb/util.py

@@ -36,6 +36,9 @@
 log.setLevel(logging.ERROR)
 
 
+dtPattern = re.compile("^(\d{4})(\d{2})?(\d{2})?(\d{2})?(\d{2})?(\d{2})?$")
+
+
 def isDaemonAlive(hostAndPort="{0}:{1}".format(IPFSAPI_HOST, IPFSAPI_PORT)):
     """Ensure that the IPFS daemon is running via HTTP before proceeding"""
     client = ipfsapi.Client(IPFSAPI_HOST, IPFSAPI_PORT)
@@ -160,6 +163,22 @@ def getRFC1123OfNow():
     return d.strftime('%a, %d %b %Y %H:%M:%S GMT')
 
 
+def padDigits14(dtstr, validate=False):
+    '''Pad datetime to make a 14-digit string and optionally validate it'''
+    match = dtPattern.match(dtstr)
+    if match:
+        Y = match.group(1)
+        m = match.group(2) or '01'
+        d = match.group(3) or '01'
+        H = match.group(4) or '00'
+        M = match.group(5) or '00'
+        S = match.group(6) or '00'
+        dtstr = '{}{}{}{}{}{}'.format(Y, m, d, H, M, S)
+    if validate:
+        datetime.datetime.strptime(dtstr, '%Y%m%d%H%M%S')
+    return dtstr
+
+
 def fetchRemoteFile(path):
     try:
         r = requests.get(path)

tests/test_util.py

@@ -0,0 +1,36 @@
+import pytest
+
+from ipwb import util
+
+
+@pytest.mark.parametrize('expected,input', [
+    ('', ''),
+    ('foo', 'foo'),
+    ('18', '18'),
+    ('20181', '20181'),
+    ('20181126134257.123', '20181126134257.123'),
+    ('20180101000000', '2018'),
+    ('20181101000000', '201811'),
+    ('20181126000000', '20181126'),
+    ('20181126130000', '2018112613'),
+    ('20181126134200', '201811261342'),
+    ('20181126134257', '20181126134257'),
+])
+def test_padDigits14(expected, input):
+    assert expected == util.padDigits14(input)
+
+
+@pytest.mark.parametrize('input', [
+    '',
+    'foo',
+    '18',
+    '20181',
+    '201800',
+    '20180132',
+    '2018010226',
+    '20180102263127',
+    '20181126134257.123',
+])
+def test_padDigits14_inalid(input):
+    with pytest.raises(ValueError):
+        util.padDigits14(input, validate=True)