Added embed support.

Backend/Embeds.py

@@ -0,0 +1,104 @@
+from __future__ import annotations
+
+import html
+import re
+
+from pathlib import Path
+from urllib.parse import quote
+
+from Core import ResolvePath
+from Explorer import ClassifyFile, GetDirectoryNoteInfo
+from Locks import IsPathAccessible
+from Portals import ResolvePortals
+from Preview import GetMimeType, ReadTextFile, TextFileTypes
+
+
+DescriptionExcerptLength = 200
+
+DefaultDescriptions = {
+    "directory": "A directory on SaraView.",
+    "video": "A video on SaraView.",
+    "image": "An image on SaraView.",
+    "note": "A note on SaraView.",
+    "file": "A file on SaraView.",
+}
+
+
+def _StripMarkdownForExcerpt(Text: str) -> str:
+    Cleaned = re.sub(r"[#*_`>~\[\]]", "", Text)
+    Cleaned = re.sub(r"\s+", " ", Cleaned).strip()
+    return Cleaned[:DescriptionExcerptLength]
+
+
+def _DescribeTextFile(RootName: str, RelativePath: str, FilePath: Path, Fallback: str) -> str:
+    try:
+        Content = ReadTextFile(FilePath)
+        Resolved = ResolvePortals(RootName, RelativePath, Content, "", [])
+        Excerpt = _StripMarkdownForExcerpt(Resolved)
+        return Excerpt or Fallback
+    except (OSError, UnicodeDecodeError):
+        return Fallback
+
+
+def _MetaTag(Property: str, Content: str) -> str:
+    return f'<meta property="{html.escape(Property)}" content="{html.escape(Content)}" />'
+
+
+def BuildOgTags(RootName: str, RelativePath: str, IsDirectoryUrl: bool, BaseUrl: str) -> str | None:
+    if not IsPathAccessible(RootName, RelativePath, "", []):
+        return None
+
+    try:
+        EntryPath = ResolvePath(RootName, RelativePath)
+    except ValueError:
+        return None
+
+    if not EntryPath.exists():
+        return None
+
+    EncodedPath = "/".join(quote(Segment) for Segment in RelativePath.split("/") if Segment)
+    PageUrl = f"{BaseUrl}/{quote(RootName)}/{EncodedPath}{'/' if IsDirectoryUrl else ''}"
+    Tags = [_MetaTag("og:url", PageUrl)]
+
+    if EntryPath.is_dir():
+        NoteInfo = GetDirectoryNoteInfo(EntryPath)
+        Description = DefaultDescriptions["directory"]
+
+        if NoteInfo is not None and NoteInfo["FileType"] in TextFileTypes:
+            NotePath = EntryPath / NoteInfo["Name"]
+            NoteRelativePath = f"{RelativePath}/{NoteInfo['Name']}" if RelativePath else NoteInfo["Name"]
+            Description = _DescribeTextFile(
+                RootName, NoteRelativePath, NotePath, DefaultDescriptions["directory"]
+            )
+
+        Tags.append(_MetaTag("og:title", EntryPath.name))
+        Tags.append(_MetaTag("og:description", Description))
+        Tags.append(_MetaTag("og:type", "website"))
+        return "\n".join(Tags)
+
+    FileType = ClassifyFile(EntryPath)
+    MediaUrl = f"{BaseUrl}/public/media/{quote(RootName)}/{EncodedPath}"
+
+    Tags.append(_MetaTag("og:title", EntryPath.name))
+
+    if FileType == "video":
+        Tags.append(_MetaTag("og:type", "video.other"))
+        Tags.append(_MetaTag("og:video", MediaUrl))
+        Tags.append(_MetaTag("og:video:url", MediaUrl))
+        Tags.append(_MetaTag("og:video:secure_url", MediaUrl))
+        Tags.append(_MetaTag("og:video:type", GetMimeType(EntryPath)))
+        Tags.append(_MetaTag("og:description", DefaultDescriptions["video"]))
+    elif FileType == "image":
+        Tags.append(_MetaTag("og:type", "website"))
+        Tags.append(_MetaTag("og:image", MediaUrl))
+        Tags.append(_MetaTag("og:image:type", GetMimeType(EntryPath)))
+        Tags.append(_MetaTag("og:description", DefaultDescriptions["image"]))
+    elif FileType in TextFileTypes:
+        Description = _DescribeTextFile(RootName, RelativePath, EntryPath, DefaultDescriptions["note"])
+        Tags.append(_MetaTag("og:type", "article"))
+        Tags.append(_MetaTag("og:description", Description))
+    else:
+        Tags.append(_MetaTag("og:type", "website"))
+        Tags.append(_MetaTag("og:description", DefaultDescriptions["file"]))
+
+    return "\n".join(Tags)