# -*- coding: utf-8 -*-
from __future__ import unicode_literals
from collections import OrderedDict
import re
from .exceptions import JsonSchemaException
from .indent import indent
from .ref_resolver import RefResolver
[docs]def enforce_list(variable):
if isinstance(variable, list):
return variable
return [variable]
# pylint: disable=too-many-instance-attributes,too-many-public-methods
[docs]class CodeGenerator(object):
"""
This class is not supposed to be used directly. Anything
inside of this class can be changed without noticing.
This class generates code of validation function from JSON
schema object as string. Example:
.. code-block:: python
CodeGenerator(json_schema_definition).func_code
"""
INDENT = 4 # spaces
def __init__(self, definition, resolver=None):
self._code = []
self._compile_regexps = {}
self._variables = set()
self._indent = 0
self._variable = None
self._variable_name = None
self._root_definition = definition
self._definition = None
# map schema URIs to validation function names for functions
# that are not yet generated, but need to be generated
self._needed_validation_functions = {}
# validation function names that are already done
self._validation_functions_done = set()
if resolver is None:
resolver = RefResolver.from_schema(definition)
self._resolver = resolver
# add main function to `self._needed_validation_functions`
self._needed_validation_functions[self._resolver.get_uri(
)] = self._resolver.get_scope_name()
self._json_keywords_to_function = OrderedDict()
@property
def func_code(self):
"""
Returns generated code of whole validation function as string.
"""
self._generate_func_code()
return '\n'.join(self._code)
@property
def global_state(self):
"""
Returns global variables for generating function from ``func_code``. Includes
compiled regular expressions and imports, so it does not have to do it every
time when validation function is called.
"""
self._generate_func_code()
return dict(
REGEX_PATTERNS=self._compile_regexps,
re=re,
JsonSchemaException=JsonSchemaException,
)
@property
def global_state_code(self):
"""
Returns global variables for generating function from ``func_code`` as code.
Includes compiled regular expressions and imports.
"""
self._generate_func_code()
if not self._compile_regexps:
return '\n'.join(
[
'from fastjsonschema import JsonSchemaException',
'',
'',
]
)
regexs = [
'"{}": re.compile(r"{}")'.format(
key,
value.pattern) for key,
value in self._compile_regexps.items()]
return '\n'.join(
[
'import re',
'from fastjsonschema import JsonSchemaException',
'',
'',
'REGEX_PATTERNS = {',
' ' + ',\n '.join(regexs),
'}',
'',
]
)
def _generate_func_code(self):
if not self._code:
self.generate_func_code()
[docs] def generate_func_code(self):
"""
Creates base code of validation function and calls helper
for creating code by definition.
"""
self.l('NoneType = type(None)')
# Generate parts that are referenced and not yet generated
while self._needed_validation_functions:
# During generation of validation function, could be needed to generate
# new one that is added again to `_needed_validation_functions`.
# Therefore usage of while instead of for loop.
uri, name = self._needed_validation_functions.popitem()
self.generate_validation_function(uri, name)
[docs] def generate_validation_function(self, uri, name):
"""
Generate validation function for given uri with given name
"""
self._validation_functions_done.add(uri)
self.l('')
with self._resolver.resolving(uri) as definition:
with self.l('def {}(data):', name):
self.generate_func_code_block(
definition, 'data', 'data', clear_variables=True)
self.l('return data')
[docs] def generate_func_code_block(
self, definition, variable, variable_name, clear_variables=False):
"""
Creates validation rules for current definition.
"""
backup = self._definition, self._variable, self._variable_name
self._definition, self._variable, self._variable_name = definition, variable, variable_name
if clear_variables:
backup_variables = self._variables
self._variables = set()
self._generate_func_code_block(definition)
self._definition, self._variable, self._variable_name = backup
if clear_variables:
self._variables = backup_variables
def _generate_func_code_block(self, definition):
if '$ref' in definition:
# needed because ref overrides any sibling keywords
self.generate_ref()
else:
self.run_generate_functions(definition)
[docs] def run_generate_functions(self, definition):
for key, func in self._json_keywords_to_function.items():
if key in definition:
func()
[docs] def generate_ref(self):
"""
Ref can be link to remote or local definition.
.. code-block:: python
{'$ref': 'http://json-schema.org/draft-04/schema#'}
{
'properties': {
'foo': {'type': 'integer'},
'bar': {'$ref': '#/properties/foo'}
}
}
"""
with self._resolver.in_scope(self._definition['$ref']):
name = self._resolver.get_scope_name()
uri = self._resolver.get_uri()
if uri not in self._validation_functions_done:
self._needed_validation_functions[uri] = name
# call validation function
self.l('{}({variable})', name)
# pylint: disable=invalid-name
@indent
def l(self, line, *args, **kwds):
"""
Short-cut of line. Used for inserting line. It's formated with parameters
``variable``, ``variable_name`` (as ``name`` for short-cut), all keys from
current JSON schema ``definition`` and also passed arguments in ``args``
and named ``kwds``.
.. code-block:: python
self.l('if {variable} not in {enum}: raise JsonSchemaException("Wrong!")')
When you want to indent block, use it as context manager. For example:
.. code-block:: python
with self.l('if {variable} not in {enum}:'):
self.l('raise JsonSchemaException("Wrong!")')
"""
spaces = ' ' * self.INDENT * self._indent
name = self._variable_name
if name and '{' in name:
name = '"+"{}".format(**locals())+"'.format(self._variable_name)
context = dict(
self._definition or {},
variable=self._variable,
name=name,
**kwds
)
self._code.append(spaces + line.format(*args, **context))
[docs] def create_variable_with_length(self):
"""
Append code for creating variable with length of that variable
(for example length of list or dictionary) with name ``{variable}_len``.
It can be called several times and always it's done only when that variable
still does not exists.
"""
variable_name = '{}_len'.format(self._variable)
if variable_name in self._variables:
return
self._variables.add(variable_name)
self.l('{variable}_len = len({variable})')
[docs] def create_variable_keys(self):
"""
Append code for creating variable with keys of that variable (dictionary)
with a name ``{variable}_keys``. Similar to `create_variable_with_length`.
"""
variable_name = '{}_keys'.format(self._variable)
if variable_name in self._variables:
return
self._variables.add(variable_name)
self.l('{variable}_keys = set({variable}.keys())')
[docs] def create_variable_is_list(self):
"""
Append code for creating variable with bool if it's instance of list
with a name ``{variable}_is_list``. Similar to `create_variable_with_length`.
"""
variable_name = '{}_is_list'.format(self._variable)
if variable_name in self._variables:
return
self._variables.add(variable_name)
self.l('{variable}_is_list = isinstance({variable}, list)')
[docs] def create_variable_is_dict(self):
"""
Append code for creating variable with bool if it's instance of list
with a name ``{variable}_is_dict``. Similar to `create_variable_with_length`.
"""
variable_name = '{}_is_dict'.format(self._variable)
if variable_name in self._variables:
return
self._variables.add(variable_name)
self.l('{variable}_is_dict = isinstance({variable}, dict)')
