DefaultPlaceholder Class — fastapi Architecture

Architecture documentation for the DefaultPlaceholder class in datastructures.py from the fastapi codebase.

Class python FastAPI

Entity Profile

FastAPI→ DefaultPlaceholder Class — fastapi Architecture

Dependency Diagram

graph TD
  c509eb0b_23fb_fa54_c7e7_d4bec7d2f3a9["DefaultPlaceholder"]
  c509eb0b_23fb_fa54_c7e7_d4bec7d2f3a9["DefaultPlaceholder"]
  c509eb0b_23fb_fa54_c7e7_d4bec7d2f3a9 -->|extends| c509eb0b_23fb_fa54_c7e7_d4bec7d2f3a9
  dc4a1804_f7b4_848b_3280_30523680d7b9["datastructures.py"]
  c509eb0b_23fb_fa54_c7e7_d4bec7d2f3a9 -->|defined in| dc4a1804_f7b4_848b_3280_30523680d7b9
  af2e5527_f157_2acc_6e72_736d3062da41["__init__()"]
  c509eb0b_23fb_fa54_c7e7_d4bec7d2f3a9 -->|method| af2e5527_f157_2acc_6e72_736d3062da41
  41204a35_c71d_abd7_9136_81de6c9e485b["__bool__()"]
  c509eb0b_23fb_fa54_c7e7_d4bec7d2f3a9 -->|method| 41204a35_c71d_abd7_9136_81de6c9e485b
  990357d0_b649_bc0a_046b_280596175fec["__eq__()"]
  c509eb0b_23fb_fa54_c7e7_d4bec7d2f3a9 -->|method| 990357d0_b649_bc0a_046b_280596175fec

Relationship Graph

Source Code

fastapi/datastructures.py lines 155–170

class DefaultPlaceholder:
    """
    You shouldn't use this class directly.

    It's used internally to recognize when a default value has been overwritten, even
    if the overridden default value was truthy.
    """

    def __init__(self, value: Any):
        self.value = value

    def __bool__(self) -> bool:
        return bool(self.value)

    def __eq__(self, o: object) -> bool:
        return isinstance(o, DefaultPlaceholder) and o.value == self.value