lxml query parsing fix: (addressing part of ukwa/ukwa-pywb#38)

- ensure lxml-enabled parsing in XmlQueryIndexSource works by passing the raw bytestring instead of unicode text to the parser
- tests: add lxml and non-lxml parsing tests to test_xmlquery_indexsource.py, add lxml to test install
- misc fixes: fix typo in banner.html, update gevent api to support latest gevent

pywb/warcserver/index/indexsource.py

@@ -248,7 +248,7 @@ class XmlQueryIndexSource(BaseIndexSource):
             response = self.session.get(query_url)
             response.raise_for_status()
 
-            results = etree.fromstring(response.text)
+            results = etree.fromstring(response.content)
 
             items = results.find('results')
 
@@ -259,7 +259,7 @@ class XmlQueryIndexSource(BaseIndexSource):
 
             raise NotFoundException('url {0} not found'.format(url))
 
-        if not items:
+        if len(items) == 0:
             raise NotFoundException('url {0} not found'.format(url))
 
         items = items.findall('result')

pywb/warcserver/index/test/test_xmlquery_indexsource.py

@@ -4,6 +4,7 @@ from pywb.warcserver.index.indexsource import XmlQueryIndexSource
 from pywb.warcserver.index.aggregator import SimpleAggregator
 
 from mock import patch
+import pytest
 
 
 # ============================================================================
@@ -27,6 +28,10 @@ def mock_get(self, url):
         def text(self):
             return self.string
 
+        @property
+        def content(self):
+            return self.string.encode('utf-8')
+
         def raise_for_status(self):
             pass
 
@@ -40,6 +45,19 @@ class TestXmlQueryIndexSource(BaseTestClass):
     def setup_class(cls):
         super(TestXmlQueryIndexSource, cls).setup_class()
 
+        cls.xmlpatch = patch('pywb.warcserver.index.indexsource.etree', cls._get_etree())
+        cls.xmlpatch.start()
+
+    @classmethod
+    def _get_etree(cls):
+        import xml.etree.ElementTree as etree
+        return etree
+
+    @classmethod
+    def teardown_class(cls):
+        cls.xmlpatch.stop()
+        super(TestXmlQueryIndexSource, cls).teardown_class()
+
     def do_query(self, params):
         return SimpleAggregator({'source': XmlQueryIndexSource('http://localhost:8080/path')})(params)
 
@@ -75,6 +93,15 @@ com,example)/some/path 20180216200300 example.warc.gz"""
         assert(errs == {})
 
 
+# ============================================================================
+class TestXmlQueryIndexSourceLXML(TestXmlQueryIndexSource):
+    @classmethod
+    def _get_etree(cls):
+        pytest.importorskip('lxml.etree')
+        import lxml.etree
+        return lxml.etree
+
+
 # ============================================================================
 URL_RESPONSE_1 = """
 <wayback>

setup.py

@@ -117,6 +117,7 @@ setup(
         'werkzeug',
         'httpbin==0.5.0',
         'ujson'
+        'lxml',
        ],
     cmdclass={'test': PyTest},
     test_suite='',