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# When adding new functions/classes to this file, you need to also add
# their types to request.pyi in this directory (a mypy stubs file that
# we use to ensure mypy does correct type inference with REQ, which it
# can't do by default due to the dynamic nature of REQ).
# Because request.pyi exists, the type annotations in this file are
# mostly not processed by mypy.
from functools import wraps
import ujson
from django.utils.translation import ugettext as _
from zerver.lib.exceptions import JsonableError, ErrorCode
from django.http import HttpRequest, HttpResponse
from typing import Any, Callable, Type
class RequestVariableMissingError(JsonableError):
data_fields = ['var_name']
def __init__(self, var_name: str) -> None:
self.var_name = var_name # type: str
def msg_format() -> str:
return _("Missing '{var_name}' argument")
class RequestVariableConversionError(JsonableError):
data_fields = ['var_name', 'bad_value']
def __init__(self, var_name: str, bad_value: Any) -> None:
self.var_name = var_name # type: str
self.bad_value = bad_value
def msg_format() -> str:
return _("Bad value for '{var_name}': {bad_value}")
# Used in conjunction with @has_request_variables, below
class REQ:
# NotSpecified is a sentinel value for determining whether a
# default value was specified for a request variable. We can't
# use None because that could be a valid, user-specified default
class _NotSpecified:
NotSpecified = _NotSpecified()
def __init__(self, whence: str=None, *, converter: Callable[[Any], Any]=None,
default: Any=NotSpecified, validator: Callable[[Any], Any]=None,
str_validator: Callable[[Any], Any]=None,
argument_type: str=None, type: Type=None) -> None:
"""whence: the name of the request variable that should be used
for this parameter. Defaults to a request variable of the
same name as the parameter.
converter: a function that takes a string and returns a new
value. If specified, this will be called on the request
variable value before passing to the function
default: a value to be used for the argument if the parameter
is missing in the request
validator: similar to converter, but takes an already parsed JSON
data structure. If specified, we will parse the JSON request
variable value before passing to the function
str_validator: Like validator, but doesn't parse JSON first.
argument_type: pass 'body' to extract the parsed JSON
corresponding to the request body
type: a hint to typing (using mypy) what the type of this parameter is.
Currently only typically necessary if default=None and the type cannot
be inferred in another way (eg. via converter).
self.post_var_name = whence
self.func_var_name = None # type: str
self.converter = converter
self.validator = validator
self.str_validator = str_validator
self.default = default
self.argument_type = argument_type
if converter and (validator or str_validator):
# Not user-facing, so shouldn't be tagged for translation
raise AssertionError('converter and validator are mutually exclusive')
if validator and str_validator:
# Not user-facing, so shouldn't be tagged for translation
raise AssertionError('validator and str_validator are mutually exclusive')
# Extracts variables from the request object and passes them as
# named function arguments. The request object must be the first
# argument to the function.
# To use, assign a function parameter a default value that is an
# instance of the REQ class. That parameter will then be automatically
# populated from the HTTP request. The request object must be the
# first argument to the decorated function.
# This should generally be the innermost (syntactically bottommost)
# decorator applied to a view, since other decorators won't preserve
# the default parameter values used by has_request_variables.
# Note that this can't be used in helper functions which are not
# expected to call json_error or json_success, as it uses json_error
# internally when it encounters an error
def has_request_variables(view_func):
# type: (Callable[[HttpRequest, Any, Any], HttpResponse]) -> Callable[[HttpRequest, *Any, **Any], HttpResponse]
num_params = view_func.__code__.co_argcount
if view_func.__defaults__ is None:
num_default_params = 0
num_default_params = len(view_func.__defaults__)
default_param_names = view_func.__code__.co_varnames[num_params - num_default_params:]
default_param_values = view_func.__defaults__
if default_param_values is None:
default_param_values = []
post_params = []
for (name, value) in zip(default_param_names, default_param_values):
if isinstance(value, REQ):
value.func_var_name = name
if value.post_var_name is None:
value.post_var_name = name
def _wrapped_view_func(request: HttpRequest, *args: Any, **kwargs: Any) -> HttpResponse:
for param in post_params:
if param.func_var_name in kwargs:
if param.argument_type == 'body':
val = ujson.loads(request.body)
except ValueError:
raise JsonableError(_('Malformed JSON'))
kwargs[param.func_var_name] = val
elif param.argument_type is not None:
# This is a view bug, not a user error, and thus should throw a 500.
raise Exception(_("Invalid argument type"))
default_assigned = False
query_params = request.GET.copy()
val = query_params[param.post_var_name]
except KeyError:
if param.default is REQ.NotSpecified:
raise RequestVariableMissingError(param.post_var_name)
val = param.default
default_assigned = True
if param.converter is not None and not default_assigned:
val = param.converter(val)
except JsonableError:
except Exception:
raise RequestVariableConversionError(param.post_var_name, val)
# Validators are like converters, but they don't handle JSON parsing; we do.
if param.validator is not None and not default_assigned:
val = ujson.loads(val)
except Exception:
raise JsonableError(_('Argument "%s" is not valid JSON.') % (param.post_var_name,))
error = param.validator(param.post_var_name, val)
if error:
raise JsonableError(error)
# str_validators is like validator, but for direct strings (no JSON parsing).
if param.str_validator is not None and not default_assigned:
error = param.str_validator(param.post_var_name, val)
if error:
raise JsonableError(error)
kwargs[param.func_var_name] = val
return view_func(request, *args, **kwargs)
return _wrapped_view_func