https://github.com/namoshizun/goodjson
Functional validators to check anything about your JSON with ease.
https://github.com/namoshizun/goodjson
functional-programming json json-schema python validation
Last synced: 2 months ago
JSON representation
Functional validators to check anything about your JSON with ease.
- Host: GitHub
- URL: https://github.com/namoshizun/goodjson
- Owner: namoshizun
- License: bsd-3-clause
- Created: 2020-10-14T15:22:04.000Z (over 4 years ago)
- Default Branch: main
- Last Pushed: 2020-10-25T02:44:25.000Z (over 4 years ago)
- Last Synced: 2023-03-09T14:32:11.959Z (about 2 years ago)
- Topics: functional-programming, json, json-schema, python, validation
- Language: Python
- Homepage:
- Size: 41 KB
- Stars: 1
- Watchers: 1
- Forks: 0
- Open Issues: 0
-
Metadata Files:
- Readme: README.md
- Changelog: CHANGELOG.md
- License: LICENSE
Awesome Lists containing this project
README
# GoodJSON
GoodJSON enables a way of building declarative JSON validation workflows through validator composition.
Coming up in v0.2.0
* Return all validation errors found instead of early quitting.
* Lazy run through of validators.
* More higher order validators.
## Installation
* Require Python >= 3.6.
* Install from GitHub: `pip install git+https://github.com/namoshizun/goodjson.git@main`
## Usage
#### Validator Function
A GoodJSON validator is a function with signature `Callable[..., Tuple[bool, ValidationFail]]`. It takes any data and returns True/False based its validity, and a `ValidationFail` object to tell exactly what value failed to meet which requirement. Each validator must accompany an `ErrorMessage`. For example, we can create a parameterizable validator that checks string prefix like below:
```python
from goodjson.errors import ErrorMessage
from goodjson.types import ValidatorFunction, CheckerReturn
from goodjson.decorators import validator
prefix_not_found = ErrorMessage(
name='prefix_not_found',
description='Expected prefix {prefix} is not found'
)
def has_prefix_value(begin_value: str) -> ValidatorFunction:
@validator(prefix_not_found.format(prefix=begin_value))
def checker(value: str) -> CheckerReturn:
# ...
# DO WHATEVER YOU WANT BECAUSE IT IS JUST A FUNCTION!
return value.startswith(begin_value)
return checker
ok, val_fail = has_prefix_value('GJ')('__notGood!')
"""
Expect "val_fail" to be printed as the following.
"path" is a dollar-sign demilited string pointing where the erroneous value is at.
Every "path" always starts with "_root_" representing the validator's input data itself.
{
'error': 'Expected prefix GJ is not found',
'data': {
'path': '_root_'
'value': '__notGood!'
}
}
"""
```
#### Primitive Validators
These are functions validating values of primitive JSON types (string, number, boolean and null). GoodJSON has already implemented several such validators such as `is_categorical`, `is_between`, `is_of_type` and `is_not_empty` etc, which can be imported from `goodjson.validators`. Check out ./examples/simple_schema.py for more examples.
#### Higher Order Validators
They run a series of validators to name/value pair and list data structures. Using them, you can compose highly flexible and complex validations in a very exprssive manner. GoodJSON implements three higher order validators:
* **foreach**: `(*validators: ValidatorFunction) -> ValidatorFunction`, applies validators to each element of an iterable data.
* **foreach_key**: `(OPTIONAL_KEYS=tuple(), **validators: List[ValidatorFunction]) -> ValidatorFunction`, applies key-paired validators to a dict-like data.
* **gj_all**: `(*validators: ValidatorFunction) -> ValidatorFunction`, feeds the input data to each validator and passes if all validators return no error.
Below is an example of building a JSON validation through validator composition. Check out ./examples/complex_schema.py for more examples.
```python
# ... reusing the has_prefix_value defined before
from goodjson.validators import foreach_key, foreach, is_string, is_list
is_good_json = foreach_key(
codes=[
is_list(),
foreach(is_string, has_prefix_value('GJ_'))
]
)
ok, val_fail = is_good_json({ 'codes': ['GJ_00001', '_00010'] })
"""
Expect "val_fail" to be printed as:
{
"error": "Expected prefix GJ_ is not found",
"data": {
"path" : "_root_$codes$1",
"value": "_00010"
}
}
"""
```