Sanitize the optional dependencies for spider API

2 files changed, 3 insertions, 27 deletions

diff --git a/synapse/rest/media/v1/media_repository.py b/synapse/rest/media/v1/media_repository.py

index 97b7e84af9..77fb0313c5 100644
--- a/synapse/rest/media/v1/media_repository.py
+++ b/synapse/rest/media/v1/media_repository.py
@@ -80,8 +80,4 @@ class MediaRepositoryResource(Resource):
         self.putChild("thumbnail", ThumbnailResource(hs, filepaths))
         self.putChild("identicon", IdenticonResource())
         if hs.config.url_preview_enabled:
-            try:
-                self.putChild("preview_url", PreviewUrlResource(hs, filepaths))
-            except Exception as e:
-                logger.warn("Failed to mount preview_url")
-                logger.exception(e)
+            self.putChild("preview_url", PreviewUrlResource(hs, filepaths))
diff --git a/synapse/rest/media/v1/preview_url_resource.py b/synapse/rest/media/v1/preview_url_resource.py

index 4dd97ac0e3..8e1cf6e2fb 100644
--- a/synapse/rest/media/v1/preview_url_resource.py
+++ b/synapse/rest/media/v1/preview_url_resource.py
@@ -40,33 +40,11 @@ import ujson as json
 import logging
 logger = logging.getLogger(__name__)
 
-try:
-    from lxml import html
-except ImportError:
-    pass
-
 
 class PreviewUrlResource(BaseMediaResource):
     isLeaf = True
 
     def __init__(self, hs, filepaths):
-        try:
-            if html:
-                pass
-        except:
-            raise RuntimeError("Disabling PreviewUrlResource as lxml not available")
-
-        if not hasattr(hs.config, "url_preview_ip_range_blacklist"):
-            logger.warn(
-                "For security, you must specify an explicit target IP address "
-                "blacklist in url_preview_ip_range_blacklist for url previewing "
-                "to work"
-            )
-            raise RuntimeError(
-                "Disabling PreviewUrlResource as "
-                "url_preview_ip_range_blacklist not specified"
-            )
-
         BaseMediaResource.__init__(self, hs, filepaths)
         self.client = SpiderHttpClient(hs)
         if hasattr(hs.config, "url_preview_url_blacklist"):
@@ -201,6 +179,8 @@ class PreviewUrlResource(BaseMediaResource):
         elif self._is_html(media_info['media_type']):
             # TODO: somehow stop a big HTML tree from exploding synapse's RAM
 
+            from lxml import html
+
             try:
                 tree = html.parse(media_info['filename'])
                 og = yield self._calc_og(tree, media_info, requester)