feature: Support XPath2.0 to 3.1 (#1774)

1 year ago · 26931e0167
parent 5229094e44
commit 26931e0167
10 changed files with 541 additions and 21 deletions
--- a/README.md
+++ b/README.md
@ -268,3 +268,7 @@ I offer commercial support, this software is depended on by network security, ae
 [license-shield]: https://img.shields.io/github/license/dgtlmoon/changedetection.io.svg?style=for-the-badge
 [release-link]: https://github.com/dgtlmoon/changedetection.io/releases
 [docker-link]: https://hub.docker.com/r/dgtlmoon/changedetection.io
+
+## Third-party licenses
+
+changedetectionio.html_tools.elementpath_tostring: Copyright (c), 2018-2021, SISSA (Scuola Internazionale Superiore di Studi Avanzati), Licensed under [MIT license](https://github.com/sissaschool/elementpath/blob/master/LICENSE)
--- a/changedetectionio/blueprint/tags/templates/edit-tag.html
+++ b/changedetectionio/blueprint/tags/templates/edit-tag.html
@ -69,11 +69,12 @@ xpath://body/div/span[contains(@class, 'example-class')]",
                                {% endif %}
                            </ul>
                        </li>
-                        <li>XPath - Limit text to this XPath rule, simply start with a forward-slash,
+                        <li>XPath - Limit text to this XPath rule, simply start with a forward-slash. To specify XPath to be used explicitly or the XPath rule starts with an XPath function: Prefix with <code>xpath:</code>
                            <ul>
-                                <li>Example:  <code>//*[contains(@class, 'sametext')]</code> or <code>xpath://*[contains(@class, 'sametext')]</code>, <a
+                                <li>Example:  <code>//*[contains(@class, 'sametext')]</code> or <code>xpath:count(//*[contains(@class, 'sametext')])</code>, <a
                                href="http://xpather.com/" target="new">test your XPath here</a></li>
                                <li>Example: Get all titles from an RSS feed <code>//title/text()</code></li>
+                                <li>To use XPath1.0: Prefix with <code>xpath1:</code></li>
                            </ul>
                            </li>
                    </ul>
--- a/changedetectionio/forms.py
+++ b/changedetectionio/forms.py
@ -328,11 +328,30 @@ class ValidateCSSJSONXPATHInput(object):
                return

            # Does it look like XPath?
-            if line.strip()[0] == '/':
+            if line.strip()[0] == '/' or line.strip().startswith('xpath:'):
                if not self.allow_xpath:
                    raise ValidationError("XPath not permitted in this field!")
                from lxml import etree, html
+                import elementpath
+                # xpath 2.0-3.1
+                from elementpath.xpath3 import XPath3Parser
                tree = html.fromstring("<html></html>")
+                line = line.replace('xpath:', '')
+
+                try:
+                    elementpath.select(tree, line.strip(), parser=XPath3Parser)
+                except elementpath.ElementPathError as e:
+                    message = field.gettext('\'%s\' is not a valid XPath expression. (%s)')
+                    raise ValidationError(message % (line, str(e)))
+                except:
+                    raise ValidationError("A system-error occurred when validating your XPath expression")
+
+            if line.strip().startswith('xpath1:'):
+                if not self.allow_xpath:
+                    raise ValidationError("XPath not permitted in this field!")
+                from lxml import etree, html
+                tree = html.fromstring("<html></html>")
+                line = line.replace('xpath1:', '')

                try:
                    tree.xpath(line.strip())
--- a/changedetectionio/html_tools.py
+++ b/changedetectionio/html_tools.py
@ -69,10 +69,89 @@ def element_removal(selectors: List[str], html_content):
    selector = ",".join(selectors)
    return subtractive_css_selector(selector, html_content)

+def elementpath_tostring(obj):
+    """
+    change elementpath.select results to string type
+    # The MIT License (MIT), Copyright (c), 2018-2021, SISSA (Scuola Internazionale Superiore di Studi Avanzati)
+    # https://github.com/sissaschool/elementpath/blob/dfcc2fd3d6011b16e02bf30459a7924f547b47d0/elementpath/xpath_tokens.py#L1038
+    """
+
+    import elementpath
+    from decimal import Decimal
+    import math
+
+    if obj is None:
+        return ''
+    # https://elementpath.readthedocs.io/en/latest/xpath_api.html#elementpath.select
+    elif isinstance(obj, elementpath.XPathNode):
+        return obj.string_value
+    elif isinstance(obj, bool):
+        return 'true' if obj else 'false'
+    elif isinstance(obj, Decimal):
+        value = format(obj, 'f')
+        if '.' in value:
+            return value.rstrip('0').rstrip('.')
+        return value
+
+    elif isinstance(obj, float):
+        if math.isnan(obj):
+            return 'NaN'
+        elif math.isinf(obj):
+            return str(obj).upper()
+
+        value = str(obj)
+        if '.' in value:
+            value = value.rstrip('0').rstrip('.')
+        if '+' in value:
+            value = value.replace('+', '')
+        if 'e' in value:
+            return value.upper()
+        return value
+
+    return str(obj)

 # Return str Utf-8 of matched rules
 def xpath_filter(xpath_filter, html_content, append_pretty_line_formatting=False, is_rss=False):
    from lxml import etree, html
+    import elementpath
+    # xpath 2.0-3.1
+    from elementpath.xpath3 import XPath3Parser
+
+    parser = etree.HTMLParser()
+    if is_rss:
+        # So that we can keep CDATA for cdata_in_document_to_text() to process
+        parser = etree.XMLParser(strip_cdata=False)
+
+    tree = html.fromstring(bytes(html_content, encoding='utf-8'), parser=parser)
+    html_block = ""
+
+    r = elementpath.select(tree, xpath_filter.strip(), namespaces={'re': 'http://exslt.org/regular-expressions'}, parser=XPath3Parser)
+    #@note: //title/text() wont work where <title>CDATA..
+
+    if type(r) != list:
+        r = [r]
+
+    for element in r:
+        # When there's more than 1 match, then add the suffix to separate each line
+        # And where the matched result doesn't include something that will cause Inscriptis to add a newline
+        # (This way each 'match' reliably has a new-line in the diff)
+        # Divs are converted to 4 whitespaces by inscriptis
+        if append_pretty_line_formatting and len(html_block) and (not hasattr( element, 'tag' ) or not element.tag in (['br', 'hr', 'div', 'p'])):
+            html_block += TEXT_FILTER_LIST_LINE_SUFFIX
+
+        if type(element) == str:
+            html_block += element
+        elif issubclass(type(element), etree._Element) or issubclass(type(element), etree._ElementTree):
+            html_block += etree.tostring(element, pretty_print=True).decode('utf-8')
+        else:
+            html_block += elementpath_tostring(element)
+
+    return html_block
+
+# Return str Utf-8 of matched rules
+# 'xpath1:'
+def xpath1_filter(xpath_filter, html_content, append_pretty_line_formatting=False, is_rss=False):
+    from lxml import etree, html

    parser = None
    if is_rss:
--- a/changedetectionio/processors/text_json_diff.py
+++ b/changedetectionio/processors/text_json_diff.py
@ -173,6 +173,11 @@ class perform_site_check(difference_detection_processor):
                                                                    html_content=self.fetcher.content,
                                                                    append_pretty_line_formatting=not watch.is_source_type_url,
                                                                    is_rss=is_rss)
+                        elif filter_rule.startswith('xpath1:'):
+                            html_content += html_tools.xpath1_filter(xpath_filter=filter_rule.replace('xpath1:', ''),
+                                                                    html_content=fetcher.content,
+                                                                    append_pretty_line_formatting=not is_source,
+                                                                    is_rss=is_rss)
                        else:
                            # CSS Filter, extract the HTML that matches and feed that into the existing inscriptis::get_text
                            html_content += html_tools.include_filters(include_filters=filter_rule,
--- a/changedetectionio/store.py
+++ b/changedetectionio/store.py
@ -848,3 +848,13 @@ class ChangeDetectionStore:
                self.data['watching'][uuid]['date_created'] = i
            i+=1
        return
+
+    # #1774 - protect xpath1 against migration
+    def update_14(self):
+        for awatch in self.__data["watching"]:
+            if self.__data["watching"][awatch]['include_filters']:
+                for num, selector in enumerate(self.__data["watching"][awatch]['include_filters']):
+                    if selector.startswith('/'):
+                        self.__data["watching"][awatch]['include_filters'][num] = 'xpath1:' + selector
+                    if selector.startswith('xpath:'):
+                        self.__data["watching"][awatch]['include_filters'][num] = selector.replace('xpath:', 'xpath1:', 1)
--- a/changedetectionio/templates/edit.html
+++ b/changedetectionio/templates/edit.html
@ -290,11 +290,12 @@ xpath://body/div/span[contains(@class, 'example-class')]",
                                {% endif %}
                            </ul>
                        </li>
-                        <li>XPath - Limit text to this XPath rule, simply start with a forward-slash,
+                        <li>XPath - Limit text to this XPath rule, simply start with a forward-slash. To specify XPath to be used explicitly or the XPath rule starts with an XPath function: Prefix with <code>xpath:</code>
                            <ul>
-                                <li>Example:  <code>//*[contains(@class, 'sametext')]</code> or <code>xpath://*[contains(@class, 'sametext')]</code>, <a
+                                <li>Example:  <code>//*[contains(@class, 'sametext')]</code> or <code>xpath:count(//*[contains(@class, 'sametext')])</code>, <a
                                href="http://xpather.com/" target="new">test your XPath here</a></li>
                                <li>Example: Get all titles from an RSS feed <code>//title/text()</code></li>
+                                <li>To use XPath1.0: Prefix with <code>xpath1:</code></li>
                            </ul>
                            </li>
                    </ul>
--- a/changedetectionio/tests/test_xpath_selector.py
+++ b/changedetectionio/tests/test_xpath_selector.py
@ -6,9 +6,11 @@ from .util import live_server_setup, wait_for_all_checks

 from ..html_tools import *

+
 def test_setup(live_server):
    live_server_setup(live_server)

+
 def set_original_response():
    test_return_data = """<html>
       <body>
@ -26,6 +28,7 @@ def set_original_response():
        f.write(test_return_data)
    return None

+
 def set_modified_response():
    test_return_data = """<html>
       <body>
@ -44,11 +47,12 @@ def set_modified_response():

    return None

+
 # Handle utf-8 charset replies https://github.com/dgtlmoon/changedetection.io/pull/613
 def test_check_xpath_filter_utf8(client, live_server):
-    filter='//item/*[self::description]'
+    filter = '//item/*[self::description]'

-    d='''<?xml version="1.0" encoding="UTF-8"?>
+    d = '''<?xml version="1.0" encoding="UTF-8"?>
 <rss xmlns:taxo="http://purl.org/rss/1.0/modules/taxonomy/" xmlns:rdf="http://www.w3.org/1999/02/22-rdf-syntax-ns#" xmlns:itunes="http://www.itunes.com/dtds/podcast-1.0.dtd" xmlns:dc="http://purl.org/dc/elements/1.1/" version="2.0">
 	<channel>
 		<title>rpilocator.com</title>
@ -102,9 +106,9 @@ def test_check_xpath_filter_utf8(client, live_server):

 # Handle utf-8 charset replies https://github.com/dgtlmoon/changedetection.io/pull/613
 def test_check_xpath_text_function_utf8(client, live_server):
-    filter='//item/title/text()'
+    filter = '//item/title/text()'

-    d='''<?xml version="1.0" encoding="UTF-8"?>
+    d = '''<?xml version="1.0" encoding="UTF-8"?>
 <rss xmlns:taxo="http://purl.org/rss/1.0/modules/taxonomy/" xmlns:rdf="http://www.w3.org/1999/02/22-rdf-syntax-ns#" xmlns:itunes="http://www.itunes.com/dtds/podcast-1.0.dtd" xmlns:dc="http://purl.org/dc/elements/1.1/" version="2.0">
 	<channel>
 		<title>rpilocator.com</title>
@ -163,15 +167,12 @@ def test_check_xpath_text_function_utf8(client, live_server):
    res = client.get(url_for("form_delete", uuid="all"), follow_redirects=True)
    assert b'Deleted' in res.data

-def test_check_markup_xpath_filter_restriction(client, live_server):

+def test_check_markup_xpath_filter_restriction(client, live_server):
    xpath_filter = "//*[contains(@class, 'sametext')]"

    set_original_response()

-    # Give the endpoint time to spin up
-    time.sleep(1)
-
    # Add our URL to the import page
    test_url = url_for('test_endpoint', _external=True)
    res = client.post(
@ -214,7 +215,6 @@ def test_check_markup_xpath_filter_restriction(client, live_server):


 def test_xpath_validation(client, live_server):
-
    # Add our URL to the import page
    test_url = url_for('test_endpoint', _external=True)
    res = client.post(
@ -235,6 +235,48 @@ def test_xpath_validation(client, live_server):
    assert b'Deleted' in res.data


+def test_xpath23_prefix_validation(client, live_server):
+    # Add our URL to the import page
+    test_url = url_for('test_endpoint', _external=True)
+    res = client.post(
+        url_for("import_page"),
+        data={"urls": test_url},
+        follow_redirects=True
+    )
+    assert b"1 Imported" in res.data
+    wait_for_all_checks(client)
+
+    res = client.post(
+        url_for("edit_page", uuid="first"),
+        data={"include_filters": "xpath:/something horrible", "url": test_url, "tags": "", "headers": "", 'fetch_backend': "html_requests"},
+        follow_redirects=True
+    )
+    assert b"is not a valid XPath expression" in res.data
+    res = client.get(url_for("form_delete", uuid="all"), follow_redirects=True)
+    assert b'Deleted' in res.data
+
+
+def test_xpath1_validation(client, live_server):
+    # Add our URL to the import page
+    test_url = url_for('test_endpoint', _external=True)
+    res = client.post(
+        url_for("import_page"),
+        data={"urls": test_url},
+        follow_redirects=True
+    )
+    assert b"1 Imported" in res.data
+    wait_for_all_checks(client)
+
+    res = client.post(
+        url_for("edit_page", uuid="first"),
+        data={"include_filters": "xpath1:/something horrible", "url": test_url, "tags": "", "headers": "", 'fetch_backend': "html_requests"},
+        follow_redirects=True
+    )
+    assert b"is not a valid XPath expression" in res.data
+    res = client.get(url_for("form_delete", uuid="all"), follow_redirects=True)
+    assert b'Deleted' in res.data
+
+
 # actually only really used by the distll.io importer, but could be handy too
 def test_check_with_prefix_include_filters(client, live_server):
    res = client.get(url_for("form_delete", uuid="all"), follow_redirects=True)
@ -254,7 +296,8 @@ def test_check_with_prefix_include_filters(client, live_server):

    res = client.post(
        url_for("edit_page", uuid="first"),
-        data={"include_filters":  "xpath://*[contains(@class, 'sametext')]", "url": test_url, "tags": "", "headers": "", 'fetch_backend': "html_requests"},
+        data={"include_filters": "xpath://*[contains(@class, 'sametext')]", "url": test_url, "tags": "", "headers": "",
+              'fetch_backend': "html_requests"},
        follow_redirects=True
    )

@ -266,13 +309,15 @@ def test_check_with_prefix_include_filters(client, live_server):
        follow_redirects=True
    )

-    assert b"Some text thats the same" in res.data #in selector
-    assert b"Some text that will change" not in res.data #not in selector
+    assert b"Some text thats the same" in res.data  # in selector
+    assert b"Some text that will change" not in res.data  # not in selector

    client.get(url_for("form_delete", uuid="all"), follow_redirects=True)
+
+
 def test_various_rules(client, live_server):
    # Just check these don't error
-    #live_server_setup(live_server)
+    # live_server_setup(live_server)
    with open("test-datastore/endpoint-content.txt", "w") as f:
        f.write("""<html>
       <body>
@ -289,6 +334,7 @@ def test_various_rules(client, live_server):
     </body>
     </html>
    """)
+
    test_url = url_for('test_endpoint', _external=True)
    res = client.post(
        url_for("import_page"),
@ -298,7 +344,6 @@ def test_various_rules(client, live_server):
    assert b"1 Imported" in res.data
    wait_for_all_checks(client)

-
    for r in ['//div', '//a', 'xpath://div', 'xpath://a']:
        res = client.post(
            url_for("edit_page", uuid="first"),
@ -313,3 +358,153 @@ def test_various_rules(client, live_server):
        assert b"Updated watch." in res.data
        res = client.get(url_for("index"))
        assert b'fetch-error' not in res.data, f"Should not see errors after '{r} filter"
+
+    res = client.get(url_for("form_delete", uuid="all"), follow_redirects=True)
+    assert b'Deleted' in res.data
+
+
+def test_xpath_20(client, live_server):
+    test_url = url_for('test_endpoint', _external=True)
+    res = client.post(
+        url_for("import_page"),
+        data={"urls": test_url},
+        follow_redirects=True
+    )
+    assert b"1 Imported" in res.data
+    wait_for_all_checks(client)
+
+    set_original_response()
+
+    test_url = url_for('test_endpoint', _external=True)
+    res = client.post(
+        url_for("edit_page", uuid="first"),
+        data={"include_filters": "//*[contains(@class, 'sametext')]|//*[contains(@class, 'changetext')]",
+              "url": test_url,
+              "tags": "",
+              "headers": "",
+              'fetch_backend': "html_requests"},
+        follow_redirects=True
+    )
+
+    assert b"Updated watch." in res.data
+    wait_for_all_checks(client)
+
+    res = client.get(
+        url_for("preview_page", uuid="first"),
+        follow_redirects=True
+    )
+
+    assert b"Some text thats the same" in res.data  # in selector
+    assert b"Some text that will change" in res.data  # in selector
+
+    client.get(url_for("form_delete", uuid="all"), follow_redirects=True)
+
+
+def test_xpath_20_function_count(client, live_server):
+    set_original_response()
+
+    # Add our URL to the import page
+    test_url = url_for('test_endpoint', _external=True)
+    res = client.post(
+        url_for("import_page"),
+        data={"urls": test_url},
+        follow_redirects=True
+    )
+    assert b"1 Imported" in res.data
+    wait_for_all_checks(client)
+
+    res = client.post(
+        url_for("edit_page", uuid="first"),
+        data={"include_filters": "xpath:count(//div) * 123456789987654321",
+              "url": test_url,
+              "tags": "",
+              "headers": "",
+              'fetch_backend': "html_requests"},
+        follow_redirects=True
+    )
+
+    assert b"Updated watch." in res.data
+    wait_for_all_checks(client)
+
+    res = client.get(
+        url_for("preview_page", uuid="first"),
+        follow_redirects=True
+    )
+
+    assert b"246913579975308642" in res.data  # in selector
+
+    client.get(url_for("form_delete", uuid="all"), follow_redirects=True)
+
+
+def test_xpath_20_function_count2(client, live_server):
+    set_original_response()
+
+    # Add our URL to the import page
+    test_url = url_for('test_endpoint', _external=True)
+    res = client.post(
+        url_for("import_page"),
+        data={"urls": test_url},
+        follow_redirects=True
+    )
+    assert b"1 Imported" in res.data
+    wait_for_all_checks(client)
+
+    res = client.post(
+        url_for("edit_page", uuid="first"),
+        data={"include_filters": "/html/body/count(div) * 123456789987654321",
+              "url": test_url,
+              "tags": "",
+              "headers": "",
+              'fetch_backend': "html_requests"},
+        follow_redirects=True
+    )
+
+    assert b"Updated watch." in res.data
+    wait_for_all_checks(client)
+
+    res = client.get(
+        url_for("preview_page", uuid="first"),
+        follow_redirects=True
+    )
+
+    assert b"246913579975308642" in res.data  # in selector
+
+    client.get(url_for("form_delete", uuid="all"), follow_redirects=True)
+
+
+def test_xpath_20_function_string_join_matches(client, live_server):
+    set_original_response()
+
+    # Add our URL to the import page
+    test_url = url_for('test_endpoint', _external=True)
+    res = client.post(
+        url_for("import_page"),
+        data={"urls": test_url},
+        follow_redirects=True
+    )
+    assert b"1 Imported" in res.data
+    wait_for_all_checks(client)
+
+    res = client.post(
+        url_for("edit_page", uuid="first"),
+        data={
+            "include_filters": "xpath:string-join(//*[contains(@class, 'sametext')]|//*[matches(@class, 'changetext')], 'specialconjunction')",
+            "url": test_url,
+            "tags": "",
+            "headers": "",
+            'fetch_backend': "html_requests"},
+        follow_redirects=True
+    )
+
+    assert b"Updated watch." in res.data
+    wait_for_all_checks(client)
+
+    res = client.get(
+        url_for("preview_page", uuid="first"),
+        follow_redirects=True
+    )
+
+    assert b"Some text thats the samespecialconjunctionSome text that will change" in res.data  # in selector
+
+    client.get(url_for("form_delete", uuid="all"), follow_redirects=True)
+
--- a/changedetectionio/tests/test_xpath_selector_unit.py
+++ b/changedetectionio/tests/test_xpath_selector_unit.py
@ -0,0 +1,203 @@
+import sys
+import os
+import pytest
+sys.path.insert(0, os.path.dirname(os.path.dirname(os.path.abspath(__file__))))
+import html_tools
+
+# test generation guide.
+# 1. Do not include encoding in the xml declaration if the test object is a str type.
+# 2. Always paraphrase test.
+
+hotels = """
+<hotel>
+  <branch location="California">
+    <staff>
+      <given_name>Christopher</given_name>
+      <surname>Anderson</surname>
+      <age>25</age>
+    </staff>
+    <staff>
+      <given_name>Christopher</given_name>
+      <surname>Carter</surname>
+      <age>30</age>
+    </staff>
+  </branch>
+  <branch location="Las Vegas">
+    <staff>
+      <given_name>Lisa</given_name>
+      <surname>Walker</surname>
+      <age>60</age>
+    </staff>
+    <staff>
+      <given_name>Jessica</given_name>
+      <surname>Walker</surname>
+      <age>32</age>
+    </staff>
+    <staff>
+      <given_name>Jennifer</given_name>
+      <surname>Roberts</surname>
+      <age>50</age>
+    </staff>
+  </branch>
+</hotel>"""
+
+@pytest.mark.parametrize("html_content", [hotels])
+@pytest.mark.parametrize("xpath, answer", [('(//staff/given_name, //staff/age)', '25'),
+                          ("xs:date('2023-10-10')", '2023-10-10'),
+                          ("if (/hotel/branch[@location = 'California']/staff[1]/age = 25) then 'is 25' else 'is not 25'", 'is 25'),
+                          ("if (//hotel/branch[@location = 'California']/staff[1]/age = 25) then 'is 25' else 'is not 25'", 'is 25'),
+                          ("if (count(/hotel/branch/staff) = 5) then true() else false()", 'true'),
+                          ("if (count(//hotel/branch/staff) = 5) then true() else false()", 'true'),
+                          ("for $i in /hotel/branch/staff return if ($i/age >= 40) then upper-case($i/surname) else lower-case($i/surname)", 'anderson'),
+                          ("given_name  =  'Christopher' and age  =  40", 'false'),
+                          ("//given_name  =  'Christopher' and //age  =  40", 'false'),
+                          #("(staff/given_name, staff/age)", 'Lisa'),
+                          ("(//staff/given_name, //staff/age)", 'Lisa'),
+                          #("hotel/branch[@location = 'California']/staff/age union hotel/branch[@location = 'Las Vegas']/staff/age", ''),
+                          ("(//hotel/branch[@location = 'California']/staff/age union //hotel/branch[@location = 'Las Vegas']/staff/age)", '60'),
+                          ("(200 to 210)", "205"),
+                          ("(//hotel/branch[@location = 'California']/staff/age union //hotel/branch[@location = 'Las Vegas']/staff/age)", "50"),
+                          ("(1, 9, 9, 5)", "5"),
+                          ("(3, (), (14, 15), 92, 653)", "653"),
+                          ("for $i in /hotel/branch/staff return $i/given_name", "Christopher"),
+                          ("for $i in //hotel/branch/staff return $i/given_name", "Christopher"),
+                          ("distinct-values(for $i in /hotel/branch/staff return $i/given_name)", "Jessica"),
+                          ("distinct-values(for $i in //hotel/branch/staff return $i/given_name)", "Jessica"),
+                          ("for $i in (7 to  15) return $i*10", "130"),
+                          ("some $i in /hotel/branch/staff satisfies $i/age < 20", "false"),
+                          ("some $i in //hotel/branch/staff satisfies $i/age < 20", "false"),
+                          ("every $i in /hotel/branch/staff satisfies $i/age > 20", "true"),
+                          ("every $i in //hotel/branch/staff satisfies $i/age > 20 ", "true"),
+                          ("let $x := branch[@location = 'California'], $y := branch[@location = 'Las Vegas'] return (avg($x/staff/age), avg($y/staff/age))", "27.5"),
+                          ("let $x := //branch[@location = 'California'], $y := //branch[@location = 'Las Vegas'] return (avg($x/staff/age), avg($y/staff/age))", "27.5"),
+                          ("let $nu := 1, $de := 1000 return  'probability = ' || $nu div $de * 100 || '%'", "0.1%"),
+                          ("let $nu := 2, $probability := function ($argument) { 'probability = ' ||  $nu div $argument  * 100 || '%'}, $de := 5 return $probability($de)", "40%"),
+                          ("'XPATH2.0-3.1 dissemination' instance of xs:string ", "true"),
+                          ("'new stackoverflow question incoming' instance of xs:integer ", "false"),
+                          ("'50000' cast as xs:integer", "50000"),
+                          ("//branch[@location = 'California']/staff[1]/surname eq 'Anderson'", "true"),
+                          ("fn:false()", "false")])
+def test_hotels(html_content, xpath, answer):
+    html_content = html_tools.xpath_filter(xpath, html_content, append_pretty_line_formatting=True)
+    assert type(html_content) == str
+    assert answer in html_content
+
+
+
+branches_to_visit = """<?xml version="1.0" ?>
+  <branches_to_visit>
+     <manager name="Godot" room_no="501">
+         <branch>Area 51</branch>
+         <branch>A place with no name</branch>
+         <branch>Stalsk12</branch>
+     </manager>
+      <manager name="Freya" room_no="305">
+         <branch>Stalsk12</branch>
+         <branch>Barcelona</branch>
+         <branch>Paris</branch>
+     </manager>
+ </branches_to_visit>"""
+@pytest.mark.parametrize("html_content", [branches_to_visit])
+@pytest.mark.parametrize("xpath, answer", [
+    ("manager[@name = 'Godot']/branch union manager[@name = 'Freya']/branch", "Area 51"),
+    ("//manager[@name = 'Godot']/branch union //manager[@name = 'Freya']/branch", "Stalsk12"),
+    ("manager[@name = 'Godot']/branch | manager[@name = 'Freya']/branch", "Stalsk12"),
+    ("//manager[@name = 'Godot']/branch | //manager[@name = 'Freya']/branch", "Stalsk12"),
+    ("manager/branch intersect manager[@name = 'Godot']/branch", "A place with no name"),
+    ("//manager/branch intersect //manager[@name = 'Godot']/branch", "A place with no name"),
+    ("manager[@name = 'Godot']/branch intersect manager[@name = 'Freya']/branch", ""),
+    ("manager/branch except manager[@name = 'Godot']/branch", "Barcelona"),
+    ("manager[@name = 'Godot']/branch[1]  eq 'Area 51'", "true"),
+    ("//manager[@name = 'Godot']/branch[1]  eq 'Area 51'", "true"),
+    ("manager[@name = 'Godot']/branch[1]  eq 'Seoul'", "false"),
+    ("//manager[@name = 'Godot']/branch[1]  eq 'Seoul'", "false"),
+    ("manager[@name = 'Godot']/branch[2] eq manager[@name = 'Freya']/branch[2]", "false"),
+    ("//manager[@name = 'Godot']/branch[2] eq //manager[@name = 'Freya']/branch[2]", "false"),
+    ("manager[1]/@room_no lt manager[2]/@room_no", "false"),
+    ("//manager[1]/@room_no lt //manager[2]/@room_no", "false"),
+    ("manager[1]/@room_no gt manager[2]/@room_no", "true"),
+    ("//manager[1]/@room_no gt //manager[2]/@room_no", "true"),
+    ("manager[@name = 'Godot']/branch[1]  = 'Area 51'", "true"),
+    ("//manager[@name = 'Godot']/branch[1]  = 'Area 51'", "true"),
+    ("manager[@name = 'Godot']/branch[1]  = 'Seoul'", "false"),
+    ("//manager[@name = 'Godot']/branch[1]  = 'Seoul'", "false"),
+    ("manager[@name = 'Godot']/branch  = 'Area 51'", "true"),
+    ("//manager[@name = 'Godot']/branch  = 'Area 51'", "true"),
+    ("manager[@name = 'Godot']/branch  = 'Barcelona'", "false"),
+    ("//manager[@name = 'Godot']/branch  = 'Barcelona'", "false"),
+    ("manager[1]/@room_no > manager[2]/@room_no", "true"),
+    ("//manager[1]/@room_no > //manager[2]/@room_no", "true"),
+    ("manager[@name = 'Godot']/branch[ . = 'Stalsk12'] is manager[1]/branch[1]", "false"),
+    ("//manager[@name = 'Godot']/branch[ . = 'Stalsk12'] is //manager[1]/branch[1]", "false"),
+    ("manager[@name = 'Godot']/branch[ . = 'Stalsk12'] is manager[1]/branch[3]", "true"),
+    ("//manager[@name = 'Godot']/branch[ . = 'Stalsk12'] is //manager[1]/branch[3]", "true"),
+    ("manager[@name = 'Godot']/branch[ . = 'Stalsk12'] <<  manager[1]/branch[1]", "false"),
+    ("//manager[@name = 'Godot']/branch[ . = 'Stalsk12'] <<  //manager[1]/branch[1]", "false"),
+    ("manager[@name = 'Godot']/branch[ . = 'Stalsk12']  >>  manager[1]/branch[1]", "true"),
+    ("//manager[@name = 'Godot']/branch[ . = 'Stalsk12'] >>  //manager[1]/branch[1]", "true"),
+    ("manager[@name = 'Godot']/branch[ . = 'Stalsk12'] is manager[@name = 'Freya']/branch[ . = 'Stalsk12']", "false"),
+    ("//manager[@name = 'Godot']/branch[ . = 'Stalsk12'] is //manager[@name = 'Freya']/branch[ . = 'Stalsk12']", "false"),
+    ("manager[1]/@name || manager[2]/@name", "GodotFreya"),
+    ("//manager[1]/@name || //manager[2]/@name", "GodotFreya"),
+                          ])
+def test_branches_to_visit(html_content, xpath, answer):
+    html_content = html_tools.xpath_filter(xpath, html_content, append_pretty_line_formatting=True)
+    assert type(html_content) == str
+    assert answer in html_content
+
+trips = """
+<trips>
+   <trip reservation_number="10">
+       <depart>2023-10-06</depart>
+       <arrive>2023-10-10</arrive>
+       <traveler name="Christopher Anderson">
+           <duration>4</duration>
+           <price>2000.00</price>
+       </traveler>
+   </trip>
+   <trip reservation_number="12">
+       <depart>2023-10-06</depart>
+       <arrive>2023-10-12</arrive>
+       <traveler name="Frank Carter">
+           <duration>6</duration>
+           <price>3500.34</price>
+       </traveler>
+   </trip>
+</trips>"""
+@pytest.mark.parametrize("html_content", [trips])
+@pytest.mark.parametrize("xpath, answer", [
+    ("1 + 9 * 9 + 5 div 5", "83"),
+    ("(1 + 9 * 9 + 5) div 6", "14.5"),
+    ("23 idiv 3", "7"),
+    ("23 div 3", "7.66666666"),
+    ("for $i in ./trip return $i/traveler/duration * $i/traveler/price", "21002.04"),
+    ("for $i in ./trip return $i/traveler/duration ", "4"),
+    ("for $i in .//trip return $i/traveler/duration * $i/traveler/price", "21002.04"),
+    ("sum(for $i in ./trip return $i/traveler/duration * $i/traveler/price)", "29002.04"),
+    ("sum(for $i in .//trip return $i/traveler/duration * $i/traveler/price)", "29002.04"),
+    #("trip[1]/depart - trip[1]/arrive", "fail_to_get_answer"),
+    #("//trip[1]/depart - //trip[1]/arrive", "fail_to_get_answer"),
+    #("trip[1]/depart + trip[1]/arrive", "fail_to_get_answer"),
+    #("xs:date(trip[1]/depart) + xs:date(trip[1]/arrive)", "fail_to_get_answer"),
+    ("(//trip[1]/arrive cast as xs:date) - (//trip[1]/depart cast as xs:date)", "P4D"),
+    ("(//trip[1]/depart cast as xs:date) - (//trip[1]/arrive cast as xs:date)", "-P4D"),
+    ("(//trip[1]/depart cast as xs:date) + xs:dayTimeDuration('P3D')", "2023-10-09"),
+    ("(//trip[1]/depart cast as xs:date) - xs:dayTimeDuration('P3D')", "2023-10-03"),
+    ("(456, 623) instance of xs:integer", "false"),
+    ("(456, 623) instance of xs:integer*", "true"),
+    ("/trips/trip instance of element()", "false"),
+    ("/trips/trip instance of element()*", "true"),
+    ("/trips/trip[1]/arrive instance of xs:date", "false"),
+    ("date(/trips/trip[1]/arrive) instance of xs:date", "true"),
+    ("'8' cast as xs:integer", "8"),
+    ("'11.1E3' cast as xs:double", "11100"),
+    ("6.5 cast as xs:integer", "6"),
+    #("/trips/trip[1]/arrive cast as xs:dateTime", "fail_to_get_answer"),
+    ("/trips/trip[1]/arrive cast as xs:date", "2023-10-10"),
+    ("('2023-10-12') cast as xs:date", "2023-10-12"),
+    ("for $i in //trip return concat($i/depart, '  ', $i/arrive)", "2023-10-06  2023-10-10"),
+                          ])
+def test_trips(html_content, xpath, answer):
+    html_content = html_tools.xpath_filter(xpath, html_content, append_pretty_line_formatting=True)
+    assert type(html_content) == str
+    assert answer in html_content
--- a/requirements.txt
+++ b/requirements.txt
@ -46,6 +46,9 @@ beautifulsoup4
 # XPath filtering, lxml is required by bs4 anyway, but put it here to be safe.
 lxml

+# XPath 2.0-3.1 support
+elementpath
+
 selenium~=4.14.0

 werkzeug~=3.0