PyUtils
Python Utils
This package contains dependency-free Python utility functions used throughout the codebase.
Each utility should belong in its own file and be the default export.
These functions are not part of the module interface and are subject to change.
- graphql.pyutils.camel_to_snake(s: str) str
Convert from CamelCase to snake_case
- graphql.pyutils.snake_to_camel(s: str, upper: bool = True) str
Convert from snake_case to CamelCase
If upper is set, then convert to upper CamelCase, otherwise the first character keeps its case.
- graphql.pyutils.cached_property(func)
- graphql.pyutils.register_description(base: type) None
Register a class that shall be accepted as a description.
- graphql.pyutils.unregister_description(base: type) None
Unregister a class that shall no more be accepted as a description.
- graphql.pyutils.did_you_mean(suggestions: Sequence[str], sub_message: Optional[str] = None) str
Given [ A, B, C ] return ‘ Did you mean A, B, or C?’
- graphql.pyutils.identity_func(x: T = Undefined, *_args: Any) T
Return the first received argument.
- graphql.pyutils.inspect(value: Any) str
Inspect value and a return string representation for error messages.
Used to print values in error messages. We do not use repr() in order to not leak too much of the inner Python representation of unknown objects, and we do not use json.dumps() because not all objects can be serialized as JSON and we want to output strings with single quotes like Python repr() does it.
We also restrict the size of the representation by truncating strings and collections and allowing only a maximum recursion depth.
- graphql.pyutils.is_awaitable(value: Any) TypeGuard[Awaitable]
Return True if object can be passed to an
await
expression.Instead of testing whether the object is an instance of abc.Awaitable, we check the existence of an __await__ attribute. This is much faster.
- graphql.pyutils.is_collection(value: Any) TypeGuard[Collection]
Check if value is a collection, but not a string or a mapping.
- graphql.pyutils.is_iterable(value: Any) TypeGuard[Iterable]
Check if value is an iterable, but not a string or a mapping.
- graphql.pyutils.natural_comparison_key(key: str) Tuple
Comparison key function for sorting strings by natural sort order.
- graphql.pyutils.AwaitableOrValue
alias of
Union
[Awaitable
[T
],T
]
- graphql.pyutils.suggestion_list(input_: str, options: Collection[str]) List[str]
Get list with suggestions for a given input.
Given an invalid input string and list of valid options, returns a filtered list of valid options sorted based on their similarity with the input.
- class graphql.pyutils.FrozenError
Bases:
TypeError
Error when trying to change a frozen (read only) collection.
- class graphql.pyutils.Path(prev: Any, key: Union[str, int], typename: Optional[str])
Bases:
NamedTuple
A generic path of string or integer indices
- __init__()
- add_key(key: Union[str, int], typename: Optional[str] = None) Path
Return a new Path containing the given key.
- as_list() List[Union[str, int]]
Return a list of the path keys.
- count(value, /)
Return number of occurrences of value.
- index(value, start=0, stop=9223372036854775807, /)
Return first index of value.
Raises ValueError if the value is not present.
- key: Union[str, int]
current index in the path (string or integer)
- prev: Any
path with the previous indices
- typename: Optional[str]
name of the parent type to avoid path ambiguity
- graphql.pyutils.print_path_list(path: Collection[Union[str, int]]) str
Build a string describing the path.
- class graphql.pyutils.SimplePubSub
Bases:
object
A very simple publish-subscript system.
Creates an AsyncIterator from an EventEmitter.
Useful for mocking a PubSub system for tests.
- __init__() None
- emit(event: Any) bool
Emit an event.
- get_subscriber(transform: Optional[Callable] = None) SimplePubSubIterator
- subscribers: Set[Callable]
- class graphql.pyutils.SimplePubSubIterator(pubsub: SimplePubSub, transform: Optional[Callable])
Bases:
AsyncIterator
- __init__(pubsub: SimplePubSub, transform: Optional[Callable]) None
- async aclose() None
- async empty_queue() None
- async push_value(event: Any) None
- graphql.pyutils.Undefined = Undefined
Symbol for undefined values
This singleton object is used to describe undefined or invalid values. It can be used in places where you would use
undefined
in GraphQL.js.