resolve_detector() — langchain Function Reference

Architecture documentation for the resolve_detector() function in _redaction.py from the langchain codebase.

Function python LangChainCore ApiManagement called by 1

Entity Profile

LangChainCore→ ApiManagement→ resolve_detector() — langchain Function Reference

Dependency Diagram

graph TD
  03fc1b05_6b22_3fec_0665_c92142ede387["resolve_detector()"]
  be639235_9a02_cc2d_5a7d_637d822fb3b3["_redaction.py"]
  03fc1b05_6b22_3fec_0665_c92142ede387 -->|defined in| be639235_9a02_cc2d_5a7d_637d822fb3b3
  a651a1ea_ba24_8836_63be_d7fa61ceb3e4["resolve()"]
  a651a1ea_ba24_8836_63be_d7fa61ceb3e4 -->|calls| 03fc1b05_6b22_3fec_0665_c92142ede387
  style 03fc1b05_6b22_3fec_0665_c92142ede387 fill:#6366f1,stroke:#818cf8,color:#fff

Relationship Graph

Source Code

libs/langchain_v1/langchain/agents/middleware/_redaction.py lines 339–376

def resolve_detector(pii_type: str, detector: Detector | str | None) -> Detector:
    """Return a callable detector for the given configuration.

    Args:
        pii_type: The PII type name.
        detector: Optional custom detector or regex pattern. If `None`, a built-in detector
            for the given PII type will be used.

    Returns:
        The resolved detector.

    Raises:
        ValueError: If an unknown PII type is specified without a custom detector or regex.
    """
    if detector is None:
        if pii_type not in BUILTIN_DETECTORS:
            msg = (
                f"Unknown PII type: {pii_type}. "
                f"Must be one of {list(BUILTIN_DETECTORS.keys())} or provide a custom detector."
            )
            raise ValueError(msg)
        return BUILTIN_DETECTORS[pii_type]
    if isinstance(detector, str):
        pattern = re.compile(detector)

        def regex_detector(content: str) -> list[PIIMatch]:
            return [
                PIIMatch(
                    type=pii_type,
                    value=match.group(),
                    start=match.start(),
                    end=match.end(),
                )
                for match in pattern.finditer(content)
            ]

        return regex_detector
    return detector