Fetch fallback site icons from DDG

DDG provides favicons using the url format
icons.duckduckgo.com/ip2/{site}.ico

This can be used to fetch favicons in the event that the default
"/favicon.ico" path does not work.

app/routes.py

@@ -17,7 +17,8 @@ from app.models.config import Config
 from app.models.endpoint import Endpoint
 from app.request import Request, TorError
 from app.utils.bangs import resolve_bang
-from app.utils.misc import empty_gif, placeholder_img, get_proxy_host_url
+from app.utils.misc import empty_gif, placeholder_img, get_proxy_host_url, \
+    fetch_favicon
 from app.filter import Filter
 from app.utils.misc import read_config_bool, get_client_ip, get_request_url, \
     check_for_update
@@ -493,7 +494,8 @@ def element():
         # Display an empty gif if the requested element couldn't be retrieved
         if response.status_code != 200 or len(response.content) == 0:
             if 'favicon' in src_url:
-                return send_file(io.BytesIO(placeholder_img), mimetype='image/png')
+                favicon = fetch_favicon(src_url)
+                return send_file(io.BytesIO(favicon), mimetype='image/png')
             else:
                 return send_file(io.BytesIO(empty_gif), mimetype='image/gif')
 

app/utils/misc.py

@@ -2,11 +2,14 @@ import base64
 from bs4 import BeautifulSoup as bsoup
 from flask import Request
 import hashlib
+import io
 import os
 import re
 from requests import exceptions, get
 from urllib.parse import urlparse
 
+ddg_favicon_site = 'http://icons.duckduckgo.com/ip2'
+
 empty_gif = base64.b64decode(
     'R0lGODlhAQABAIAAAP///////yH5BAEKAAEALAAAAAABAAEAAAICTAEAOw==')
 
@@ -21,6 +24,29 @@ placeholder_img = base64.b64decode(
 )
 
 
+def fetch_favicon(url: str) -> bytes:
+    """Fetches a favicon using DuckDuckGo's favicon retriever
+
+    Args:
+        url: The url to fetch the favicon from
+    Returns:
+        bytes - the favicon bytes, or a placeholder image if one
+        was not returned
+    """
+    domain = urlparse(url).netloc
+
+    response = get(f'{ddg_favicon_site}/{domain}.ico')
+
+    if response.status_code == 200 and len(response.content) > 0:
+        tmp_mem = io.BytesIO()
+        tmp_mem.write(response.content)
+        tmp_mem.seek(0)
+
+        return tmp_mem.read()
+    else:
+        return placeholder_img
+
+
 def gen_file_hash(path: str, static_file: str) -> str:
     file_contents = open(os.path.join(path, static_file), 'rb').read()
     file_hash = hashlib.md5(file_contents).hexdigest()[:8]