Social embeds with oEmbed and Open Graph

server/config.yaml.dist

@@ -169,6 +169,9 @@ privileges:
     'uploads:create':               regular
     'uploads:use_downloader':       power
 
+homepage_url: https://www.example.com/
+site_url: https://www.example.com/booru
+
 ## ONLY SET THESE IF DEPLOYING OUTSIDE OF DOCKER
 #debug: 0 # generate server logs?
 #show_sql: 0 # show sql in server logs?

server/szurubooru/api/__init__.py

@@ -1,4 +1,5 @@
 import szurubooru.api.comment_api
+import szurubooru.api.embed_api
 import szurubooru.api.info_api
 import szurubooru.api.password_reset_api
 import szurubooru.api.pool_api

server/szurubooru/api/embed_api.py

@@ -0,0 +1,101 @@
+import re
+import html
+from urllib.parse import quote
+from typing import Dict, Optional
+
+from szurubooru import config, model, rest
+from szurubooru.func import (
+    auth,
+    posts,
+    serialization,
+)
+
+with open(f"{config.config['data_dir']}/../index.htm") as index:
+    index_html = index.read()
+
+def _index_path(params: Dict[str, str]) -> int:
+    try:
+        return params["path"]
+    except (TypeError, ValueError):
+        raise posts.InvalidPostIdError(
+            "Invalid post ID."
+        )
+
+
+def _get_post(post_id: int) -> model.Post:
+    return posts.get_post_by_id(post_id)
+
+
+def _get_post_id(match: re.Match) -> int:
+    post_id = match.group("post_id")
+    try:
+        return int(post_id)
+    except (TypeError, ValueError):
+        raise posts.InvalidPostIdError(
+            "Invalid post ID: %r." % post_id
+        )
+
+
+def _serialize_post(
+    ctx: rest.Context, post: Optional[model.Post]
+) -> rest.Response:
+    return posts.serialize_post(
+        post, ctx.user, options=["thumbnailUrl", "user"]
+    )
+
+
+@rest.routes.get("/oembed/?")
+def get_post(
+    ctx: rest.Context, _params: Dict[str, str] = {}, url: str = ""
+) -> rest.Response:
+    auth.verify_privilege(ctx.user, "posts:view")
+
+    url = url or ctx.get_param_as_string("url")
+    match = re.match(r".*?/post/(?P<post_id>\d+)", url)
+    if not match:
+        raise posts.InvalidPostIdError("Invalid post ID.")
+
+    post_id = _get_post_id(match)
+    post = _get_post(post_id)
+    serialized = _serialize_post(ctx, post)
+    embed = {
+        "version": "1.0",
+        "type": "photo",
+        "title": f"{config.config['name']} – Post #{post_id}",
+        "author_name": serialized["user"]["name"] if serialized["user"] else None,
+        "provider_name": config.config["name"],
+        "provider_url": config.config["homepage_url"],
+        "thumbnail_url": f"{config.config['site_url']}/{serialized['thumbnailUrl']}",
+        "thumbnail_width": int(config.config["thumbnails"]["post_width"]),
+        "thumbnail_height": int(config.config["thumbnails"]["post_height"]),
+        "url": f"{config.config['site_url']}/{serialized['thumbnailUrl']}",
+        "width": int(config.config["thumbnails"]["post_width"]),
+        "height": int(config.config["thumbnails"]["post_height"])
+    }
+    return embed
+
+
+@rest.routes.get("/index(?P<path>/.+)")
+def post_index(ctx: rest.Context, params: Dict[str, str]) -> rest.Response:
+    path = _index_path(params)
+    try:
+        oembed = get_post(ctx, {}, path)
+    except posts.PostNotFoundError:
+        return {"return_type": "custom", "status_code": "404", "content": index_html}
+
+    url = config.config["site_url"] + path
+    new_html = index_html.replace("</head>", f'''
+<meta property="og:site_name" content="{config.config["name"]}">
+<meta property="og:url" content="{html.escape(url)}">
+<meta property="og:type" content="article">
+<meta property="og:title" content="{html.escape(oembed['title'])}">
+<meta name="twitter:title" content="{html.escape(oembed['title'])}">
+<meta name="twitter:card" content="summary_large_image">
+<meta name="twitter:image" content="{html.escape(oembed['url'])}">
+<meta property="og:image:url" content="{html.escape(oembed['url'])}">
+<meta property="og:image:width" content="{oembed['width']}">
+<meta property="og:image:height" content="{oembed['height']}">
+<meta property="article:author" content="{html.escape(oembed['author_name'] or '')}">
+<link rel="alternate" type="application/json+oembed" href="{config.config["site_url"]}/api/oembed?url={quote(html.escape(url))}" title="{html.escape(config.config["name"])}"></head>
+''').replace("<html>", '<html prefix="og: http://ogp.me/ns#">').replace("<title>Loading...</title>", f"<title>{html.escape(oembed['title'])}</title>")
+    return {"return_type": "custom", "content": new_html}

server/szurubooru/rest/app.py

@@ -74,7 +74,8 @@ def application(
 ) -> Tuple[bytes]:
     try:
         ctx = _create_context(env)
-        if "application/json" not in ctx.get_header("Accept"):
+        accept_header = ctx.get_header("Accept")
+        if "*/*" not in accept_header and "application/json" not in accept_header:
             raise errors.HttpNotAcceptable(
                 "ValidationError", "This API only supports JSON responses."
             )
@@ -111,6 +112,10 @@ def application(
             finally:
                 db.session.remove()
 
+            if type(response) == dict and response.get("return_type") == "custom":
+                start_response(response.get("status_code", "200"), [("content-type", "text/html")])
+                return (response.get("content", "").encode("utf-8"),)
+
             start_response("200", [("content-type", "application/json")])
             return (_dump_json(response).encode("utf-8"),)