Remove lxml dependency

The lxml dependency in the project was fairly unnecessary, and made the
initial build time for the project considerably slower. This replaces
all instances of lxml with either the default html parser (for bs4
constructors) or the built in xml.etree package (for search suggestion
parsing).

app/filter.py

@@ -111,8 +111,8 @@ class Filter:
             return
 
         # Wrap section in details element to allow collapse/expand
-        details = BeautifulSoup(features='lxml').new_tag('details')
+        details = BeautifulSoup(features='html.parser').new_tag('details')
-        summary = BeautifulSoup(features='lxml').new_tag('summary')
+        summary = BeautifulSoup(features='html.parser').new_tag('summary')
         summary.string = question_divs[0].find('h2').text
         question_divs[0].find('h2').decompose()
         details.append(summary)

app/request.py

@@ -1,5 +1,5 @@
 from app.models.config import Config
-from lxml import etree
+import xml.etree.ElementTree as ET
 import random
 import requests
 from requests import Response, ConnectionError
@@ -185,12 +185,13 @@ class Request:
         response = self.send(base_url=AUTOCOMPLETE_URL,
                              query=urlparse.urlencode(ac_query)).text
 
-        if response:
+        if not response:
-            dom = etree.fromstring(response)
-            return dom.xpath('//suggestion/@data')
-
             return []
 
+        root = ET.fromstring(response)
+        return [_.attrib['data'] for _ in
+                root.findall('.//suggestion/[@data]')]
+
     def send(self, base_url=SEARCH_URL, query='', attempt=0) -> Response:
         """Sends an outbound request to a URL. Optionally sends the request
         using Tor, if enabled by the user.

app/utils/filter_utils.py

@@ -75,7 +75,7 @@ def filter_link_args(query_link):
 
 
 def gen_nojs(sibling):
-    nojs_link = BeautifulSoup(features='lxml').new_tag('a')
+    nojs_link = BeautifulSoup(features='html.parser').new_tag('a')
     nojs_link['href'] = '/window?location=' + sibling['href']
     nojs_link['style'] = 'display:block;width:100%;'
     nojs_link.string = 'NoJS Link: ' + nojs_link['href']

requirements.txt

@@ -12,7 +12,6 @@ Flask-Session==0.3.2
 idna==2.9
 itsdangerous==1.1.0
 Jinja2==2.10.3
-lxml==4.5.1
 MarkupSafe==1.1.1
 more-itertools==8.3.0
 packaging==20.4