detect_credit_card() — langchain Function Reference

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

Function python LangChainCore ApiManagement calls 1

Entity Profile

LangChainCore→ ApiManagement→ detect_credit_card() — langchain Function Reference

Dependency Diagram

graph TD
  8ccbd42d_daf9_c9d1_b6b8_ad43da8f7d49["detect_credit_card()"]
  be639235_9a02_cc2d_5a7d_637d822fb3b3["_redaction.py"]
  8ccbd42d_daf9_c9d1_b6b8_ad43da8f7d49 -->|defined in| be639235_9a02_cc2d_5a7d_637d822fb3b3
  2b14d9ef_16cf_fd2a_5e5f_1d51c05d3294["_passes_luhn()"]
  8ccbd42d_daf9_c9d1_b6b8_ad43da8f7d49 -->|calls| 2b14d9ef_16cf_fd2a_5e5f_1d51c05d3294
  style 8ccbd42d_daf9_c9d1_b6b8_ad43da8f7d49 fill:#6366f1,stroke:#818cf8,color:#fff

Relationship Graph

Source Code

libs/langchain_v1/langchain/agents/middleware/_redaction.py lines 71–95

def detect_credit_card(content: str) -> list[PIIMatch]:
    """Detect credit card numbers in content using Luhn validation.

    Args:
        content: The text content to scan for credit card numbers.

    Returns:
        A list of detected credit card matches.
    """
    pattern = r"\b\d{4}[\s-]?\d{4}[\s-]?\d{4}[\s-]?\d{4}\b"
    matches = []

    for match in re.finditer(pattern, content):
        card_number = match.group()
        if _passes_luhn(card_number):
            matches.append(
                PIIMatch(
                    type="credit_card",
                    value=card_number,
                    start=match.start(),
                    end=match.end(),
                )
            )

    return matches