40 lines
1.4 KiB
Python
40 lines
1.4 KiB
Python
"""Slug value object for URL-friendly identifiers."""
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import re
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from dataclasses import dataclass
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from app.domain.value_objects.base import ValueObject
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@dataclass(frozen=True, slots=True)
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class Slug(ValueObject[str]):
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"""URL slug value object."""
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MAX_LENGTH: int = 200
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SLUG_PATTERN: str = r"^[a-z0-9]+(?:-[a-z0-9]+)*$"
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def _validate(self) -> None:
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if not isinstance(self.value, str):
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raise ValueError("Slug must be a string")
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if len(self.value) > self.MAX_LENGTH:
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raise ValueError(f"Slug must be at most {self.MAX_LENGTH} characters")
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if not re.match(self.SLUG_PATTERN, self.value):
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raise ValueError("Slug must contain only lowercase letters, numbers, and hyphens")
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@classmethod
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def from_title(cls, title: str) -> "Slug":
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"""Generate slug from title."""
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# Convert to lowercase, replace spaces with hyphens
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slug = title.lower().strip()
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# Keep only alphanumeric, spaces, and hyphens
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slug = re.sub(r"[^a-z0-9\s-]", "", slug)
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# Replace spaces and multiple hyphens with single hyphen
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slug = re.sub(r"[-\s]+", "-", slug)
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# Limit length and strip hyphens
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max_len = 200 # Same as MAX_LENGTH
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slug = slug[:max_len].strip("-")
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# Ensure we have at least one character
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if not slug:
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slug = "post"
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return cls(value=slug)
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