Add redirects for at.tumblr.com links

locales/en_US/LC_MESSAGES/priviblur.po

@@ -128,3 +128,6 @@ msgstr "Error: Unable to fetch HTTP client in time"
 
 msgid "priviblur_error_pool_timeout_error_description"
 msgstr "Priviblur was unable to fetch a HTTP client to request Tumblr in time. Please try again later"
+
+msgid "priviblur_error_invalid_internal_tumblr_redirect"
+msgstr "Error: Tumblr HTTP 301 redirect points to foreign URL"

src/helpers/error_handlers.py

@@ -26,6 +26,7 @@ async def tumblr_error_restricted_tag(request, exception):
         status=403
     )
 
+
 async def tumblr_error_unknown_blog(request, exception):
     return await sanic_ext.render(
         "misc/generic_error.jinja",
@@ -81,3 +82,15 @@ async def error_404(request, exception):
         },
     status=404
     )
+
+
+async def invalid_redirect(request, exception):
+    return await sanic_ext.render(
+        "misc/generic_error.jinja",
+        context={
+            "app": request.app,
+            "exception": exception,
+            "error_heading": request.app.ctx.translate("en", "priviblur_error_invalid_internal_tumblr_redirect"),
+        },
+    status=502
+    )

src/helpers/exceptions.py

@@ -0,0 +1,2 @@
+class TumblrInvalidRedirect(Exception):
+    pass

src/helpers/helpers.py

@@ -1,9 +1,9 @@
-import sanic
-
 import copy
 import urllib.parse
 from typing import Sequence
 
+import sanic
+
 def url_handler(raw_url):
     """Change URLs found in posts to privacy-friendly alternatives"""
     url = urllib.parse.urlparse(raw_url)

src/routes/__init__.py

@@ -1,4 +1,4 @@
-from . import explore, media, search, tagged, blogs, assets, priviblur
+from . import explore, media, search, tagged, blogs, assets, priviblur, miscellaneous
 
 BLUEPRINTS = (
     explore.explore,
@@ -7,5 +7,6 @@
     tagged.tagged,
     blogs.blogs,
     assets.assets,
-    priviblur.priviblur
+    priviblur.priviblur,
+    miscellaneous.miscellaneous
 )

src/routes/media.py

@@ -1,5 +1,7 @@
 import sanic
 
+from ..helpers import exceptions
+
 media = sanic.Blueprint("TumblrMedia", url_prefix="/tblr")
 
 
@@ -15,7 +17,7 @@ async def get_media(request, client, path_to_request):
             if location := priviblur_response_headers.get("location"):
                 location = request.app.ctx.URL_HANDLER(location)
                 if not location.startswith("/"):
-                    return sanic.response.text("Media is redirecting to foreign URL", status=500)
+                    raise exceptions.TumblrInvalidRedirect()
 
                 return sanic.redirect(location)
         elif tumblr_response.status_code == 429:

src/routes/miscellaneous.py

@@ -0,0 +1,17 @@
+import urllib.parse
+
+import sanic
+from ..helpers import exceptions
+
+miscellaneous = sanic.Blueprint("miscellaneous", url_prefix="/")
+
+@miscellaneous.get(r"/at/<path:path>")
+async def _at_links(request: sanic.Request, path : str):
+    """Redirects for at.tumblr.com links"""
+    response = await request.app.ctx.TumblrAtClient.head(path)
+    if response.status_code == 301:
+        location = urllib.parse.urlparse(response.headers["location"])
+        if location.path.startswith("/"):
+            return sanic.redirect(location.path)
+
+    raise exceptions.TumblrInvalidRedirect()

src/server.py

@@ -18,7 +18,7 @@
 from . import routes, priviblur_extractor
 from . import priviblur_extractor
 from .config import load_config
-from .helpers import setup_logging, helpers, error_handlers, pool_timeout_tracker
+from .helpers import setup_logging, helpers, error_handlers, exceptions, pool_timeout_tracker
 from .version import VERSION, CURRENT_COMMIT
 from .jobs import refresh_pool
 
@@ -64,7 +64,6 @@
 
 @app.listener("before_server_start")
 async def initialize(app):
-
     priviblur_backend = app.ctx.PRIVIBLUR_CONFIG.backend
 
     app.ctx.TumblrAPI = await priviblur_extractor.TumblrAPI.create(
@@ -100,6 +99,13 @@ def create_image_client(url):
 
     tasks.append(app.add_task(refresh_pool.refresh_pool_task(app, create_image_client)))
 
+    app.ctx.TumblrAtClient = httpx.AsyncClient(
+        base_url="https://at.tumblr.com",
+        headers={"user-agent": priviblur_extractor.TumblrAPI.DEFAULT_HEADERS["user-agent"]},
+        http2=True,
+        timeout=priviblur_backend.main_response_timeout
+    )
+
     # Add additional jinja filters and functions
 
     app.ext.environment.filters["encodepathsegment"] = functools.partial(urllib.parse.quote, safe="")
@@ -182,6 +188,7 @@ async def reload_shutdown(app):
 
 app.error_handler.add(httpx.PoolTimeout, error_handlers.pool_timeout_error)
 app.error_handler.add(sanic.exceptions.NotFound, error_handlers.error_404)
+app.error_handler.add(exceptions.TumblrInvalidRedirect, error_handlers.invalid_redirect)
 
 # Register all routes:
 for route in routes.BLUEPRINTS: