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ksmithandClaude Sonnet 5
54932c9c03
A URL that points straight at an image file (Content-Type: image/*) has no HTML to scrape Open Graph tags from, so the fetch found nothing and the message showed no preview at all -- reported against https://imgs.xkcd.com/comics/creepy.png. link_preview_service now recognizes an allowed image content-type (same list storage.py uses for uploads) before falling through to the HTML/og: path, and returns the URL itself as the preview (LinkPreview.is_image). No need to download the body -- the already-SSRF-validated URL is the image. The frontend renders that case as a real expandable image (message-image + lightbox, same as an actual attachment) instead of the small title+description card, which would have nothing to show anyway. Verified end-to-end against the reported URL. Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>
39 lines
1.8 KiB
Python
39 lines
1.8 KiB
Python
import uuid
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from datetime import datetime
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from sqlalchemy import Boolean, DateTime, String, func
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from sqlalchemy.orm import Mapped, mapped_column
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from app.models.base import Base
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class LinkPreview(Base):
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"""A cache keyed by URL, not by message -- multiple messages (in the
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same room or different ones) linking the same URL share one fetch
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instead of each triggering their own. link_preview_service is the only
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writer; Message.preview_url (the first URL found in a message's
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content, set at creation time) is the join key a caller looks this up
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by."""
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__tablename__ = "link_previews"
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id: Mapped[uuid.UUID] = mapped_column(primary_key=True, default=uuid.uuid4)
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url: Mapped[str] = mapped_column(String(2048), unique=True, index=True, nullable=False)
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title: Mapped[str | None] = mapped_column(String(500))
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description: Mapped[str | None] = mapped_column(String(1000))
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image_url: Mapped[str | None] = mapped_column(String(2048))
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site_name: Mapped[str | None] = mapped_column(String(200))
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# A direct link to an image file (Content-Type: image/*, no HTML to
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# scrape og: tags from) gets image_url = the URL itself and no
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# title/description/site_name -- this flags that case so the frontend
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# renders it as an actual expanded image rather than the small
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# title+description unfurl card.
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is_image: Mapped[bool] = mapped_column(Boolean, default=False, nullable=False)
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# Cached separately from a "no row yet" state so a URL that genuinely
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# doesn't unfurl (no title, fetch error, blocked by SSRF checks) isn't
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# re-fetched on every message that references it within the TTL.
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fetch_failed: Mapped[bool] = mapped_column(Boolean, default=False, nullable=False)
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fetched_at: Mapped[datetime] = mapped_column(
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DateTime(timezone=True), server_default=func.clock_timestamp(), nullable=False
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)
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