Validol2
Useful GET/POST-parameters or JSON parsing* and validation tool.
- It doesn't actually parse textual data. It operates on python data structures.
Why
- Checks that supplied data is valid (supports optional keys in dictionaries)
- Automatically converts types for you
- Very extensible
- License that gives you unlimited usage scenarios :-)
Usage
>>> validate(str, "foo")
'foo'
>>> validate(int, 10)
10
>>> validate(int, "10")
10
>>> validate([int], ["10"])
[10]
>>> validate(sequence([int]), xrange(10))
[0, 1, 2, 3, 4, 5, 6, 7, 8, 9]
>>> validate({"user": str,
... "blocked": boolean,
... "email": str},
... {"user": "john",
... "blocked": "false",
... "email": "john@example.com"}
... )
{'blocked': False, 'email': 'john@example.com', 'user': 'john'}
>>> validate(any_of([10, 20, 30]), 10)
Too long/didn't read
Imagine that you expect a GET request of the following form: {"page": "10"}
On server-side you need to check that the only supplied parameter is "page", that its value is an integer and it is greater than zero (negative pages are weird).
Here's how validol2 helps you: >>> validate({"page": gt(0)}, # so-called scheme {"page": "10"}) # the GET-request {"page": 10}
As you can see, you got back data from the GET-request, but 10 is not a string anymore. More than that, it is checked to be greater than zero!
What's going on here?
Scheme
Scheme is a pattern for data you expect. It is used for both validation and type conversion.
Breakdown of {"page": gt(0)}:
- {...} - means that we expect a dictionary
- "page": ... - means that we expect only one key with value "page"
- gt(0) - means that we expect an numeric which is greater than zero (also conversion to integer happens here)
Extensibility
Forgot to mention that validol2 is very extensible! For example: from validol2 import validate, ValidationError
def upper_case(expected):
def _upper_case(value):
if value == expected
return value
raise ValidationError("Expected %s to be upper case!" % (value,))
return _upper_case
print validate(upper_case(str), "FOO") # will print FOO
print validate(upper_case(str), "foo") # will raise an exception
That's the only effort you need to extend validol2.
PS Yes, you can think of validol2 as of forms without forms.
Tips on testing
python validol2.py
If nothing is printed then tests pass.
python tests.py
Eventually I plan to move all the tests into tests.py (I don't like doctests).
Credits
License
See LICENSE file. Long story short: WTFPL v2
