diff --git a/searx/engines/bing.py b/searx/engines/bing.py
index 1e614867b..ed0b87dbd 100644
--- a/searx/engines/bing.py
+++ b/searx/engines/bing.py
@@ -18,7 +18,7 @@ from lxml import html
 from searx import logger, utils
 from searx.engines.xpath import extract_text
 from searx.url_utils import urlencode
-from searx.utils import match_language, gen_useragent
+from searx.utils import match_language, gen_useragent, eval_xpath
 
 logger = logger.getChild('bing engine')
 
@@ -65,11 +65,11 @@ def response(resp):
 
     dom = html.fromstring(resp.text)
     # parse results
-    for result in dom.xpath('//div[@class="sa_cc"]'):
-        link = result.xpath('.//h3/a')[0]
+    for result in eval_xpath(dom, '//div[@class="sa_cc"]'):
+        link = eval_xpath(result, './/h3/a')[0]
         url = link.attrib.get('href')
         title = extract_text(link)
-        content = extract_text(result.xpath('.//p'))
+        content = extract_text(eval_xpath(result, './/p'))
 
         # append result
         results.append({'url': url,
@@ -77,11 +77,11 @@ def response(resp):
                         'content': content})
 
     # parse results again if nothing is found yet
-    for result in dom.xpath('//li[@class="b_algo"]'):
-        link = result.xpath('.//h2/a')[0]
+    for result in eval_xpath(dom, '//li[@class="b_algo"]'):
+        link = eval_xpath(result, './/h2/a')[0]
         url = link.attrib.get('href')
         title = extract_text(link)
-        content = extract_text(result.xpath('.//p'))
+        content = extract_text(eval_xpath(result, './/p'))
 
         # append result
         results.append({'url': url,
@@ -89,7 +89,7 @@ def response(resp):
                         'content': content})
 
     try:
-        result_len_container = "".join(dom.xpath('//span[@class="sb_count"]/text()'))
+        result_len_container = "".join(eval_xpath(dom, '//span[@class="sb_count"]/text()'))
         result_len_container = utils.to_string(result_len_container)
         if "-" in result_len_container:
             # Remove the part "from-to" for paginated request ...
@@ -113,9 +113,9 @@ def response(resp):
 def _fetch_supported_languages(resp):
     supported_languages = []
     dom = html.fromstring(resp.text)
-    options = dom.xpath('//div[@id="limit-languages"]//input')
+    options = eval_xpath(dom, '//div[@id="limit-languages"]//input')
     for option in options:
-        code = option.xpath('./@id')[0].replace('_', '-')
+        code = eval_xpath(option, './@id')[0].replace('_', '-')
         if code == 'nb':
             code = 'no'
         supported_languages.append(code)
diff --git a/searx/engines/dictzone.py b/searx/engines/dictzone.py
index 09db048cc..423af0971 100644
--- a/searx/engines/dictzone.py
+++ b/searx/engines/dictzone.py
@@ -11,7 +11,7 @@
 
 import re
 from lxml import html
-from searx.utils import is_valid_lang
+from searx.utils import is_valid_lang, eval_xpath
 from searx.url_utils import urljoin
 
 categories = ['general']
@@ -47,14 +47,14 @@ def response(resp):
 
     dom = html.fromstring(resp.text)
 
-    for k, result in enumerate(dom.xpath(results_xpath)[1:]):
+    for k, result in enumerate(eval_xpath(dom, results_xpath)[1:]):
         try:
-            from_result, to_results_raw = result.xpath('./td')
+            from_result, to_results_raw = eval_xpath(result, './td')
         except:
             continue
 
         to_results = []
-        for to_result in to_results_raw.xpath('./p/a'):
+        for to_result in eval_xpath(to_results_raw, './p/a'):
             t = to_result.text_content()
             if t.strip():
                 to_results.append(to_result.text_content())
diff --git a/searx/engines/doku.py b/searx/engines/doku.py
index a391be444..d20e66026 100644
--- a/searx/engines/doku.py
+++ b/searx/engines/doku.py
@@ -11,6 +11,7 @@
 
 from lxml.html import fromstring
 from searx.engines.xpath import extract_text
+from searx.utils import eval_xpath
 from searx.url_utils import urlencode
 
 # engine dependent config
@@ -45,16 +46,16 @@ def response(resp):
 
     # parse results
     # Quickhits
-    for r in doc.xpath('//div[@class="search_quickresult"]/ul/li'):
+    for r in eval_xpath(doc, '//div[@class="search_quickresult"]/ul/li'):
         try:
-            res_url = r.xpath('.//a[@class="wikilink1"]/@href')[-1]
+            res_url = eval_xpath(r, './/a[@class="wikilink1"]/@href')[-1]
         except:
             continue
 
         if not res_url:
             continue
 
-        title = extract_text(r.xpath('.//a[@class="wikilink1"]/@title'))
+        title = extract_text(eval_xpath(r, './/a[@class="wikilink1"]/@title'))
 
         # append result
         results.append({'title': title,
@@ -62,13 +63,13 @@ def response(resp):
                         'url': base_url + res_url})
 
     # Search results
-    for r in doc.xpath('//dl[@class="search_results"]/*'):
+    for r in eval_xpath(doc, '//dl[@class="search_results"]/*'):
         try:
             if r.tag == "dt":
-                res_url = r.xpath('.//a[@class="wikilink1"]/@href')[-1]
-                title = extract_text(r.xpath('.//a[@class="wikilink1"]/@title'))
+                res_url = eval_xpath(r, './/a[@class="wikilink1"]/@href')[-1]
+                title = extract_text(eval_xpath(r, './/a[@class="wikilink1"]/@title'))
             elif r.tag == "dd":
-                content = extract_text(r.xpath('.'))
+                content = extract_text(eval_xpath(r, '.'))
 
                 # append result
                 results.append({'title': title,
diff --git a/searx/engines/duckduckgo.py b/searx/engines/duckduckgo.py
index e77ef0126..0d2c0af2d 100644
--- a/searx/engines/duckduckgo.py
+++ b/searx/engines/duckduckgo.py
@@ -18,7 +18,7 @@ from json import loads
 from searx.engines.xpath import extract_text
 from searx.poolrequests import get
 from searx.url_utils import urlencode
-from searx.utils import match_language
+from searx.utils import match_language, eval_xpath
 
 # engine dependent config
 categories = ['general']
@@ -106,19 +106,19 @@ def response(resp):
     doc = fromstring(resp.text)
 
     # parse results
-    for i, r in enumerate(doc.xpath(result_xpath)):
+    for i, r in enumerate(eval_xpath(doc, result_xpath)):
         if i >= 30:
             break
         try:
-            res_url = r.xpath(url_xpath)[-1]
+            res_url = eval_xpath(r, url_xpath)[-1]
         except:
             continue
 
         if not res_url:
             continue
 
-        title = extract_text(r.xpath(title_xpath))
-        content = extract_text(r.xpath(content_xpath))
+        title = extract_text(eval_xpath(r, title_xpath))
+        content = extract_text(eval_xpath(r, content_xpath))
 
         # append result
         results.append({'title': title,
diff --git a/searx/engines/duden.py b/searx/engines/duden.py
index 444f18c1f..cf2f1a278 100644
--- a/searx/engines/duden.py
+++ b/searx/engines/duden.py
@@ -11,6 +11,7 @@
 from lxml import html, etree
 import re
 from searx.engines.xpath import extract_text
+from searx.utils import eval_xpath
 from searx.url_utils import quote, urljoin
 from searx import logger
 
@@ -52,9 +53,9 @@ def response(resp):
     dom = html.fromstring(resp.text)
 
     try:
-        number_of_results_string = re.sub('[^0-9]', '', dom.xpath(
-            '//a[@class="active" and contains(@href,"/suchen/dudenonline")]/span/text()')[0]
-        )
+        number_of_results_string =\
+            re.sub('[^0-9]', '',
+                   eval_xpath(dom, '//a[@class="active" and contains(@href,"/suchen/dudenonline")]/span/text()')[0])
 
         results.append({'number_of_results': int(number_of_results_string)})
 
@@ -62,12 +63,12 @@ def response(resp):
         logger.debug("Couldn't read number of results.")
         pass
 
-    for result in dom.xpath('//section[not(contains(@class, "essay"))]'):
+    for result in eval_xpath(dom, '//section[not(contains(@class, "essay"))]'):
         try:
-            url = result.xpath('.//h2/a')[0].get('href')
+            url = eval_xpath(result, './/h2/a')[0].get('href')
             url = urljoin(base_url, url)
-            title = result.xpath('string(.//h2/a)').strip()
-            content = extract_text(result.xpath('.//p'))
+            title = eval_xpath(result, 'string(.//h2/a)').strip()
+            content = extract_text(eval_xpath(result, './/p'))
             # append result
             results.append({'url': url,
                             'title': title,
diff --git a/searx/engines/gigablast.py b/searx/engines/gigablast.py
index 6b0402233..a84f3f69d 100644
--- a/searx/engines/gigablast.py
+++ b/searx/engines/gigablast.py
@@ -15,6 +15,7 @@ from json import loads
 from time import time
 from lxml.html import fromstring
 from searx.url_utils import urlencode
+from searx.utils import eval_xpath
 
 # engine dependent config
 categories = ['general']
@@ -99,9 +100,9 @@ def response(resp):
 def _fetch_supported_languages(resp):
     supported_languages = []
     dom = fromstring(resp.text)
-    links = dom.xpath('//span[@id="menu2"]/a')
+    links = eval_xpath(dom, '//span[@id="menu2"]/a')
     for link in links:
-        href = link.xpath('./@href')[0].split('lang%3A')
+        href = eval_xpath(link, './@href')[0].split('lang%3A')
         if len(href) == 2:
             code = href[1].split('_')
             if len(code) == 2:
diff --git a/searx/engines/google.py b/searx/engines/google.py
index 0a0d6ccb1..19bde710d 100644
--- a/searx/engines/google.py
+++ b/searx/engines/google.py
@@ -14,7 +14,7 @@ from lxml import html, etree
 from searx.engines.xpath import extract_text, extract_url
 from searx import logger
 from searx.url_utils import urlencode, urlparse, parse_qsl
-from searx.utils import match_language
+from searx.utils import match_language, eval_xpath
 
 logger = logger.getChild('google engine')
 
@@ -156,7 +156,7 @@ def parse_url(url_string, google_hostname):
 
 # returns extract_text on the first result selected by the xpath or None
 def extract_text_from_dom(result, xpath):
-    r = result.xpath(xpath)
+    r = eval_xpath(result, xpath)
     if len(r) > 0:
         return extract_text(r[0])
     return None
@@ -227,21 +227,21 @@ def response(resp):
     # convert the text to dom
     dom = html.fromstring(resp.text)
 
-    instant_answer = dom.xpath('//div[@id="_vBb"]//text()')
+    instant_answer = eval_xpath(dom, '//div[@id="_vBb"]//text()')
     if instant_answer:
         results.append({'answer': u' '.join(instant_answer)})
     try:
-        results_num = int(dom.xpath('//div[@id="resultStats"]//text()')[0]
+        results_num = int(eval_xpath(dom, '//div[@id="resultStats"]//text()')[0]
                           .split()[1].replace(',', ''))
         results.append({'number_of_results': results_num})
     except:
         pass
 
     # parse results
-    for result in dom.xpath(results_xpath):
+    for result in eval_xpath(dom, results_xpath):
         try:
-            title = extract_text(result.xpath(title_xpath)[0])
-            url = parse_url(extract_url(result.xpath(url_xpath), google_url), google_hostname)
+            title = extract_text(eval_xpath(result, title_xpath)[0])
+            url = parse_url(extract_url(eval_xpath(result, url_xpath), google_url), google_hostname)
             parsed_url = urlparse(url, google_hostname)
 
             # map result
@@ -250,7 +250,7 @@ def response(resp):
                 continue
                 # if parsed_url.path.startswith(maps_path) or parsed_url.netloc.startswith(map_hostname_start):
                 #     print "yooooo"*30
-                #     x = result.xpath(map_near)
+                #     x = eval_xpath(result, map_near)
                 #     if len(x) > 0:
                 #         # map : near the location
                 #         results = results + parse_map_near(parsed_url, x, google_hostname)
@@ -287,11 +287,11 @@ def response(resp):
             continue
 
     # parse suggestion
-    for suggestion in dom.xpath(suggestion_xpath):
+    for suggestion in eval_xpath(dom, suggestion_xpath):
         # append suggestion
         results.append({'suggestion': extract_text(suggestion)})
 
-    for correction in dom.xpath(spelling_suggestion_xpath):
+    for correction in eval_xpath(dom, spelling_suggestion_xpath):
         results.append({'correction': extract_text(correction)})
 
     # return results
@@ -300,9 +300,9 @@ def response(resp):
 
 def parse_images(result, google_hostname):
     results = []
-    for image in result.xpath(images_xpath):
-        url = parse_url(extract_text(image.xpath(image_url_xpath)[0]), google_hostname)
-        img_src = extract_text(image.xpath(image_img_src_xpath)[0])
+    for image in eval_xpath(result, images_xpath):
+        url = parse_url(extract_text(eval_xpath(image, image_url_xpath)[0]), google_hostname)
+        img_src = extract_text(eval_xpath(image, image_img_src_xpath)[0])
 
         # append result
         results.append({'url': url,
@@ -389,10 +389,10 @@ def attributes_to_html(attributes):
 def _fetch_supported_languages(resp):
     supported_languages = {}
     dom = html.fromstring(resp.text)
-    options = dom.xpath('//*[@id="langSec"]//input[@name="lr"]')
+    options = eval_xpath(dom, '//*[@id="langSec"]//input[@name="lr"]')
     for option in options:
-        code = option.xpath('./@value')[0].split('_')[-1]
-        name = option.xpath('./@data-name')[0].title()
+        code = eval_xpath(option, './@value')[0].split('_')[-1]
+        name = eval_xpath(option, './@data-name')[0].title()
         supported_languages[code] = {"name": name}
 
     return supported_languages
diff --git a/searx/engines/startpage.py b/searx/engines/startpage.py
index 0f0ec6e18..76567396f 100644
--- a/searx/engines/startpage.py
+++ b/searx/engines/startpage.py
@@ -16,6 +16,7 @@ from datetime import datetime, timedelta
 import re
 from searx.engines.xpath import extract_text
 from searx.languages import language_codes
+from searx.utils import eval_xpath
 
 # engine dependent config
 categories = ['general']
@@ -70,8 +71,8 @@ def response(resp):
     dom = html.fromstring(resp.text)
 
     # parse results
-    for result in dom.xpath(results_xpath):
-        links = result.xpath(link_xpath)
+    for result in eval_xpath(dom, results_xpath):
+        links = eval_xpath(result, link_xpath)
         if not links:
             continue
         link = links[0]
@@ -87,8 +88,8 @@ def response(resp):
 
         title = extract_text(link)
 
-        if result.xpath(content_xpath):
-            content = extract_text(result.xpath(content_xpath))
+        if eval_xpath(result, content_xpath):
+            content = extract_text(eval_xpath(result, content_xpath))
         else:
             content = ''
 
diff --git a/searx/engines/wikidata.py b/searx/engines/wikidata.py
index 5ea2b9958..e913b3915 100644
--- a/searx/engines/wikidata.py
+++ b/searx/engines/wikidata.py
@@ -16,7 +16,7 @@ from searx.poolrequests import get
 from searx.engines.xpath import extract_text
 from searx.engines.wikipedia import _fetch_supported_languages, supported_languages_url
 from searx.url_utils import urlencode
-from searx.utils import match_language
+from searx.utils import match_language, eval_xpath
 
 from json import loads
 from lxml.html import fromstring
@@ -57,22 +57,6 @@ language_fallback_xpath = '//sup[contains(@class,"wb-language-fallback-indicator
 calendar_name_xpath = './/sup[contains(@class,"wb-calendar-name")]'
 media_xpath = value_xpath + '//div[contains(@class,"commons-media-caption")]//a'
 
-# xpath_cache
-xpath_cache = {}
-
-
-def get_xpath(xpath_str):
-    result = xpath_cache.get(xpath_str, None)
-    if not result:
-        result = etree.XPath(xpath_str)
-        xpath_cache[xpath_str] = result
-    return result
-
-
-def eval_xpath(element, xpath_str):
-    xpath = get_xpath(xpath_str)
-    return xpath(element)
-
 
 def get_id_cache(result):
     id_cache = {}
diff --git a/searx/engines/xpath.py b/searx/engines/xpath.py
index 61494ce4e..b75896cc7 100644
--- a/searx/engines/xpath.py
+++ b/searx/engines/xpath.py
@@ -1,6 +1,6 @@
 from lxml import html
 from lxml.etree import _ElementStringResult, _ElementUnicodeResult
-from searx.utils import html_to_text
+from searx.utils import html_to_text, eval_xpath
 from searx.url_utils import unquote, urlencode, urljoin, urlparse
 
 search_url = None
@@ -104,15 +104,15 @@ def response(resp):
     results = []
     dom = html.fromstring(resp.text)
     if results_xpath:
-        for result in dom.xpath(results_xpath):
-            url = extract_url(result.xpath(url_xpath), search_url)
-            title = extract_text(result.xpath(title_xpath))
-            content = extract_text(result.xpath(content_xpath))
+        for result in eval_xpath(dom, results_xpath):
+            url = extract_url(eval_xpath(result, url_xpath), search_url)
+            title = extract_text(eval_xpath(result, title_xpath))
+            content = extract_text(eval_xpath(result, content_xpath))
             tmp_result = {'url': url, 'title': title, 'content': content}
 
             # add thumbnail if available
             if thumbnail_xpath:
-                thumbnail_xpath_result = result.xpath(thumbnail_xpath)
+                thumbnail_xpath_result = eval_xpath(result, thumbnail_xpath)
                 if len(thumbnail_xpath_result) > 0:
                     tmp_result['img_src'] = extract_url(thumbnail_xpath_result, search_url)
 
@@ -120,14 +120,14 @@ def response(resp):
     else:
         for url, title, content in zip(
             (extract_url(x, search_url) for
-             x in dom.xpath(url_xpath)),
-            map(extract_text, dom.xpath(title_xpath)),
-            map(extract_text, dom.xpath(content_xpath))
+             x in eval_xpath(dom, url_xpath)),
+            map(extract_text, eval_xpath(dom, title_xpath)),
+            map(extract_text, eval_xpath(dom, content_xpath))
         ):
             results.append({'url': url, 'title': title, 'content': content})
 
     if not suggestion_xpath:
         return results
-    for suggestion in dom.xpath(suggestion_xpath):
+    for suggestion in eval_xpath(dom, suggestion_xpath):
         results.append({'suggestion': extract_text(suggestion)})
     return results
diff --git a/searx/engines/yahoo.py b/searx/engines/yahoo.py
index 73b78bcf7..36c1a11f8 100644
--- a/searx/engines/yahoo.py
+++ b/searx/engines/yahoo.py
@@ -14,7 +14,7 @@
 from lxml import html
 from searx.engines.xpath import extract_text, extract_url
 from searx.url_utils import unquote, urlencode
-from searx.utils import match_language
+from searx.utils import match_language, eval_xpath
 
 # engine dependent config
 categories = ['general']
@@ -109,21 +109,21 @@ def response(resp):
     dom = html.fromstring(resp.text)
 
     try:
-        results_num = int(dom.xpath('//div[@class="compPagination"]/span[last()]/text()')[0]
+        results_num = int(eval_xpath(dom, '//div[@class="compPagination"]/span[last()]/text()')[0]
                           .split()[0].replace(',', ''))
         results.append({'number_of_results': results_num})
     except:
         pass
 
     # parse results
-    for result in dom.xpath(results_xpath):
+    for result in eval_xpath(dom, results_xpath):
         try:
-            url = parse_url(extract_url(result.xpath(url_xpath), search_url))
-            title = extract_text(result.xpath(title_xpath)[0])
+            url = parse_url(extract_url(eval_xpath(result, url_xpath), search_url))
+            title = extract_text(eval_xpath(result, title_xpath)[0])
         except:
             continue
 
-        content = extract_text(result.xpath(content_xpath)[0])
+        content = extract_text(eval_xpath(result, content_xpath)[0])
 
         # append result
         results.append({'url': url,
@@ -131,7 +131,7 @@ def response(resp):
                         'content': content})
 
     # if no suggestion found, return results
-    suggestions = dom.xpath(suggestion_xpath)
+    suggestions = eval_xpath(dom, suggestion_xpath)
     if not suggestions:
         return results
 
@@ -148,9 +148,9 @@ def response(resp):
 def _fetch_supported_languages(resp):
     supported_languages = []
     dom = html.fromstring(resp.text)
-    options = dom.xpath('//div[@id="yschlang"]/span/label/input')
+    options = eval_xpath(dom, '//div[@id="yschlang"]/span/label/input')
     for option in options:
-        code_parts = option.xpath('./@value')[0][5:].split('_')
+        code_parts = eval_xpath(option, './@value')[0][5:].split('_')
         if len(code_parts) == 2:
             code = code_parts[0] + '-' + code_parts[1].upper()
         else:
diff --git a/searx/results.py b/searx/results.py
index a127024c8..3b1e4bd62 100644
--- a/searx/results.py
+++ b/searx/results.py
@@ -67,8 +67,9 @@ def merge_two_infoboxes(infobox1, infobox2):
 
         for url2 in infobox2.get('urls', []):
             unique_url = True
-            for url1 in infobox1.get('urls', []):
-                if compare_urls(urlparse(url1.get('url', '')), urlparse(url2.get('url', ''))):
+            parsed_url2 = urlparse(url2.get('url', ''))
+            for url1 in urls1:
+                if compare_urls(urlparse(url1.get('url', '')), parsed_url2):
                     unique_url = False
                     break
             if unique_url:
@@ -188,8 +189,9 @@ class ResultContainer(object):
         add_infobox = True
         infobox_id = infobox.get('id', None)
         if infobox_id is not None:
+            parsed_url_infobox_id = urlparse(infobox_id)
             for existingIndex in self.infoboxes:
-                if compare_urls(urlparse(existingIndex.get('id', '')), urlparse(infobox_id)):
+                if compare_urls(urlparse(existingIndex.get('id', '')), parsed_url_infobox_id):
                     merge_two_infoboxes(existingIndex, infobox)
                     add_infobox = False
 
diff --git a/searx/utils.py b/searx/utils.py
index e61a134f7..5ea9dc89c 100644
--- a/searx/utils.py
+++ b/searx/utils.py
@@ -13,6 +13,7 @@ from numbers import Number
 from os.path import splitext, join
 from io import open
 from random import choice
+from lxml.etree import XPath
 import sys
 import json
 
@@ -51,6 +52,7 @@ ecma_unescape2_re = re.compile(r'%([0-9a-fA-F]{2})', re.UNICODE)
 useragents = json.loads(open(os.path.dirname(os.path.realpath(__file__))
                              + "/data/useragents.json", 'r', encoding='utf-8').read())
 
+xpath_cache = dict()
 lang_to_lc_cache = dict()
 
 
@@ -450,3 +452,16 @@ def get_engine_from_settings(name):
             return engine
 
     return {}
+
+
+def get_xpath(xpath_str):
+    result = xpath_cache.get(xpath_str, None)
+    if result is None:
+        result = XPath(xpath_str)
+        xpath_cache[xpath_str] = result
+    return result
+
+
+def eval_xpath(element, xpath_str):
+    xpath = get_xpath(xpath_str)
+    return xpath(element)
diff --git a/searx/webapp.py b/searx/webapp.py
index 183bf1975..7cf4106d3 100644
--- a/searx/webapp.py
+++ b/searx/webapp.py
@@ -157,20 +157,18 @@ outgoing_proxies = settings['outgoing'].get('proxies') or None
 
 @babel.localeselector
 def get_locale():
-    locale = request.accept_languages.best_match(settings['locales'].keys())
-
-    if request.preferences.get_value('locale') != '':
-        locale = request.preferences.get_value('locale')
+    if 'locale' in request.form\
+       and request.form['locale'] in settings['locales']:
+        return request.form['locale']
 
     if 'locale' in request.args\
        and request.args['locale'] in settings['locales']:
-        locale = request.args['locale']
+        return request.args['locale']
 
-    if 'locale' in request.form\
-       and request.form['locale'] in settings['locales']:
-        locale = request.form['locale']
+    if request.preferences.get_value('locale') != '':
+        return request.preferences.get_value('locale')
 
-    return locale
+    return request.accept_languages.best_match(settings['locales'].keys())
 
 
 # code-highlighter