Filtering Techniques

import re

class PIIFilter:
    PATTERNS = {
        "email": r"\b[A-Za-z0-9._%+-]+@[A-Za-z0-9.-]+\.[A-Z|a-z]{2,}\b",
        "phone_us": r"\b(\+?1[-.]?)?\(?\d{3}\)?[-.]?\d{3}[-.]?\d{4}\b",
        "ssn": r"\b\d{3}-\d{2}-\d{4}\b",
        "credit_card": r"\b\d{4}[-\s]?\d{4}[-\s]?\d{4}[-\s]?\d{4}\b",
        "ip_address": r"\b\d{1,3}\.\d{1,3}\.\d{1,3}\.\d{1,3}\b",
    }

    def redact(self, text: str) -> dict:
        redacted = text
        findings = []
        for pii_type, pattern in self.PATTERNS.items():
            matches = re.findall(pattern, redacted)
            if matches:
                findings.append({"type": pii_type, "count": len(matches)})
                redacted = re.sub(pattern, f"[{pii_type.upper()}_REDACTED]", redacted)
        return {"text": redacted, "findings": findings}

class BlocklistFilter:
    def __init__(self):
        self.hard_block = [# Always block]
        self.soft_block = [# Flag for review]
        self.context_block = [# Block only in certain contexts]

    def check(self, text: str) -> dict:
        text_lower = text.lower()
        for phrase in self.hard_block:
            if phrase in text_lower:
                return {"action": "block", "reason": phrase}
        for phrase in self.soft_block:
            if phrase in text_lower:
                return {"action": "review", "reason": phrase}
        return {"action": "allow"}