问题
I am converting a Python3 application to use WebKit2 instead of WebKit (which is no longer available in Debian Buster).
In the application the user can (de)select check boxes which I read from the Python3 application. In the original code I could simply get the DomDocument of the Webview and iterate through the child objects to return the value of the object with a given name (sample code below).
In WebKit2 the get_dom_document function is no longer available and the WebKit2 documentation is not clear on how to proceed.
Does anybody know how to get the DomDocument from a WebKit2 Webview or another way to iterate through all objects by name and get their value?
Sample code DomDocument from WebKit Webview:
def get_element_values(self, element_name):
values = []
doc = self.get_dom_document()
elements = doc.get_elements_by_name(element_name)
for i in range(elements.get_length()):
child = elements.item(i)
value = child.get_value().strip()
if not child.get_checked():
value = ''
if value:
values.append(value)
return values
Note: "self" is the WebKit.Webview.
[EDIT]
I have been experimenting with this. First I tried to get the DomDocument by getting the WebPage object first. I found WebView.get_page_id() and WebKit2WebExtension.get_page(page_id) but unfortunately that gave me this error: AttributeError: 'gi.repository.WebKit2WebExtension' object has no attribute 'get_page'.
After that I tried JavaScriptCore and insert JavaScript with WebView.run_javascript() and WebView.run_javascript_finish(). I get a JavaScriptResult object back but when I try to get the value with .get_value() I get this error: TypeError: Couldn't find foreign struct converter for 'JavaScriptCore.Value'.
There was a user with the same issue here, but the proposed solution was too complicated for me as well.
Here's the code I used for testing (check the get_element_values() and javascript_finished() functions):
#! /usr/bin/env python3
# WebKit2 reference: https://webkitgtk.org/reference/webkit2gtk/stable
# Code examples: https://github.com/sidus-dev/poseidon/blob/master/poseidon.py
import gi
gi.require_version('WebKit2', '4.0')
gi.require_version('WebKit2WebExtension', '4.0')
from gi.repository import WebKit2, WebKit2WebExtension, Gtk
from os.path import exists
import webbrowser
import re
class SimpleBrowser(WebKit2.WebView):
def __init__(self):
WebKit2.WebView.__init__(self)
# Get version
self.webkit_ver = WebKit2.get_major_version(), WebKit2.get_minor_version(), WebKit2.get_micro_version()
print(("WebKit2 Version: {0}".format('.'.join(map(str, self.webkit_ver)))))
# Signals
self.connect('decide-policy', self.on_decide_policy)
#self.connect("load_changed", self.on_load_changed)
self.connect("load-failed", self.on_load_failed)
self.connect('button-press-event', lambda w, e: e.button == 3)
# Settings
s = self.get_settings()
s.set_property('allow_file_access_from_file_urls', True)
s.set_property('enable-spatial-navigation', False)
s.set_property('enable_javascript', True)
def show_html(self, html_or_url):
if exists(html_or_url):
matchObj = re.search('^file:\/\/', html_or_url)
if not matchObj:
html_or_url = "file://{0}".format(html_or_url)
matchObj = re.search('^[a-z]+:\/\/', html_or_url)
if matchObj:
self.load_uri(html_or_url)
else:
self.load_html(html_or_url)
self.show()
def get_element_values(self, object, element_name):
# JavaScript > dead end :(
# https://webkitgtk.org/reference/webkit2gtk/stable/WebKitWebView.html#webkit-web-view-run-javascript
js = 'var e = document.getElementsByName("' + element_name + '"); var r = []; var c = 0; ' \
'for (var i = 0; i < e.length; i++) { if (e[i].checked) { r[c] = e[i].value; c++;} }'
self.run_javascript(js, None, self.javascript_finished, None);
return
# DOM > dead end :(
# https://webkitgtk.org/reference/webkit2gtk/stable/WebKitWebPage.html
# https://webkitgtk.org/reference/webkit2gtk/stable/WebKitWebView.html#webkit-web-view-get-page-id
page_id = self.get_page_id()
print((page_id))
# https://webkitgtk.org/reference/webkit2gtk/stable/WebKitWebExtension.html#webkit-web-extension-get-page
# AttributeError: 'gi.repository.WebKit2WebExtension' object has no attribute 'get_page'
web_page = WebKit2WebExtension.get_page(page_id)
print((web_page))
def javascript_finished(self, webview, result, user_data):
# https://webkitgtk.org/reference/webkit2gtk/stable/WebKitWebView.html#webkit-web-view-run-javascript-finish
js_result = self.run_javascript_finish(result)
print((">>> js_result = %s" % str(js_result)))
# TypeError: Couldn't find foreign struct converter for 'JavaScriptCore.Value'
value = js_result.get_value()
print((">>> value = %s" % str(value)))
def on_decide_policy(self, webview, decision, decision_type):
# User clicked on a <a href link: open uri in new tab or new default webview
if (decision_type == WebKit2.PolicyDecisionType.NAVIGATION_ACTION):
action = decision.get_navigation_action()
action_type = action.get_navigation_type()
if action_type == WebKit2.NavigationType.LINK_CLICKED:
decision.ignore()
uri = action.get_request().get_uri()
# Open link in default browser
webbrowser.open_new_tab(uri)
else:
if decision is not None:
decision.use()
def on_load_changed(webview, event):
# TODO: get html of loaded page
if event == WebKit2.LoadEvent.FINISHED:
resource = webview.get_main_resource()
resource.get_data()
html = resource.get_data_finish(None)
print(html)
def on_load_failed(webview, event, url, error):
print("Error loading", url, "-", error)
html = '<html><body style="background-color:#E6E6E6;"><h1>WebKit2 Test</h1>' \
'<p><a href="https://solydxk.com">link</a></p><form onsubmit="return false;">' \
'<input type="checkbox" name="chktst" value="checkbox1" checked /> CheckBox 1<br />' \
'<input type="checkbox" name="chktst" value="checkbox2" /> CheckBox 2<br />' \
'<button onclick="alert(show_values());">JS Show Values</button>' \
'</form>' \
'<script>' \
'function show_values() {' \
'var e = document.getElementsByName("chktst"); var r = []; var c = 0;' \
'for (var i = 0; i < e.length; i++) {' \
' if (e[i].checked) { r[c] = e[i].value; c++;}' \
'}return r;}' \
'</script>' \
'</body></html>'
win = Gtk.Window()
win.connect("delete-event", Gtk.main_quit)
win.set_default_size(600,400)
webview = SimpleBrowser()
webview.show_html(html)
box = Gtk.Box.new(Gtk.Orientation.VERTICAL, 0)
button = Gtk.Button(label="Python Show Values")
button.connect("clicked", webview.get_element_values, 'chktst')
win.add(box)
box.pack_start(webview, True, True, 0)
box.pack_start(button, False, False, 1)
win.show_all()
Gtk.main()
[EDIT2]
In Debian Stretch you need to install the packages from backports:
sudo apt-get install -t stretch-backports gir1.2-javascriptcoregtk-4.0 gir1.2-webkit2-4.0 libjavascriptcoregtk-4.0-18 libwebkit2gtk-4.0-37 libwebkit2gtk-4.0-37-gtk2
Now, WebKit2.JavascriptResult.get_js_value() will return a JavaScriptCore.Value object. I will test this further and post back an answer if I find one.
Check this bug report: https://bugs.webkit.org/show_bug.cgi?id=136989
回答1:
I found out that if I would return the getElementsByClassName object itself the following error was thrown:
GLib.Error: WebKitJavascriptError: (699)
Which only tells me it failed.
I could however let the JavaScript function return a string or array with values and convert that to a string in Python.
Not ideal, but it is workable for what I need it to do.
Here's the example code (check the comments for further information):
#! /usr/bin/env python3
# WebKit2 reference: https://webkitgtk.org/reference/webkit2gtk/stable
import gi
gi.require_version('Gtk', '3.0')
gi.require_version('WebKit2', '4.0')
from gi.repository import Gtk
from gi.repository import WebKit2
from gi.repository import GObject
from os.path import exists
import webbrowser
import re
import sys
class SimpleBrowser(WebKit2.WebView):
# Create custom signals
__gsignals__ = {
"js-finished" : (GObject.SignalFlags.RUN_LAST, GObject.TYPE_NONE, ()),
"html-response-finished" : (GObject.SignalFlags.RUN_LAST, GObject.TYPE_NONE, ())
}
def __init__(self):
WebKit2.WebView.__init__(self)
# Get version
webkit_ver = WebKit2.get_major_version(), WebKit2.get_minor_version(), WebKit2.get_micro_version()
print(("WebKit2 Version: {0}".format('.'.join(map(str, webkit_ver)))))
if webkit_ver[0] < 2 or \
webkit_ver[1] < 22:
print(("ERROR: upgrade WebKit2 to version 2.22.x or higher"))
sys.exit()
# Store JS output
self.js_value = None
# Store html response
self.html_response = None
# WebKit2 Signals
self.connect('decide-policy', self.on_decide_policy)
self.connect("load_changed", self.on_load_changed)
self.connect("load-failed", self.on_load_failed)
self.connect('button-press-event', lambda w, e: e.button == 3)
# Settings
s = self.get_settings()
s.set_property('allow_file_access_from_file_urls', True)
s.set_property('enable-spatial-navigation', False)
s.set_property('enable_javascript', True)
def show_html(self, html_or_url):
if exists(html_or_url):
matchObj = re.search('^file:\/\/', html_or_url)
if not matchObj:
html_or_url = "file://{0}".format(html_or_url)
matchObj = re.search('^[a-z]+:\/\/', html_or_url)
if matchObj:
self.load_uri(html_or_url)
else:
self.load_html(html_or_url)
self.show()
def js_run(self, function_name, js_return=True):
# JavaScript
# https://webkitgtk.org/reference/webkit2gtk/stable/WebKitWebView.html#webkit-web-view-run-javascript
run_js_finish = self._js_finish if js_return else None
self.run_javascript(function_name, None, run_js_finish, None);
def _js_finish(self, webview, result, user_data=None):
# https://webkitgtk.org/reference/webkit2gtk/stable/WebKitWebView.html#webkit-web-view-run-javascript-finish
js_result = self.run_javascript_finish(result)
if js_result is not None:
# https://webkitgtk.org/reference/jsc-glib/stable/JSCValue.html
# TypeError: Couldn't find foreign struct converter for 'JavaScriptCore.Value':
# Make sure you have WebKit2 2.22.x or higher installed.
# For Debian Stretch you need the backports packages:
# apt install -t stretch-backports gir1.2-javascriptcoregtk-4.0 gir1.2-webkit2-4.0 libjavascriptcoregtk-4.0-18 libwebkit2gtk-4.0-37 libwebkit2gtk-4.0-37-gtk2
# Couldn't handle anything but string :(
# If returning the getElementsByClassName object itself: GLib.Error: WebKitJavascriptError: (699)
value = js_result.get_js_value()
self.js_value = value.to_string()
#print((self.js_value))
self.emit('js-finished')
def on_decide_policy(self, webview, decision, decision_type):
# User clicked on a <a href link: open uri in new tab or new default webview
if (decision_type == WebKit2.PolicyDecisionType.NAVIGATION_ACTION):
action = decision.get_navigation_action()
action_type = action.get_navigation_type()
if action_type == WebKit2.NavigationType.LINK_CLICKED:
decision.ignore()
uri = action.get_request().get_uri()
# Open link in default browser
webbrowser.open_new_tab(uri)
else:
if decision is not None:
decision.use()
def on_load_changed(self, webview, event):
# Get html of loaded page
if event == WebKit2.LoadEvent.FINISHED:
resource = webview.get_main_resource()
resource.get_data(None, self._get_response_data_finish, None)
def _get_response_data_finish(self, resource, result, user_data=None):
self.html_response = resource.get_data_finish(result)
self.emit('html-response-finished')
def on_load_failed(webview, event, url, error):
print("Error loading", url, "-", error)
html = '<html>' \
'<script>' \
'function get_checked_values(class_name) {' \
'var e = document.getElementsByClassName(class_name); var r = []; var c = 0;' \
'if (e.length == 0) { e = document.getElementsById(class_name); }' \
'for (var i = 0; i < e.length; i++) {' \
' if (e[i].checked) { r[c] = e[i].value; c++;}' \
'}return r;}' \
'</script>' \
'</head><body style="background-color:#E6E6E6;"><h1>WebKit2 JavaScript Test</h1>' \
'<p><a href="https://solydxk.com">link</a></p><form onsubmit="return false;">' \
'<input type="checkbox" class="chktst" value="checkbox1" checked /> CheckBox 1<br />' \
'<input type="checkbox" class="chktst" value="checkbox2" /> CheckBox 2<br />' \
'</form></body></html>'
# Create test window
win = Gtk.Window()
webview = SimpleBrowser()
win.set_default_size(600,400)
button = Gtk.Button(label="Python Show Checked Values")
box = Gtk.Box.new(Gtk.Orientation.VERTICAL, 0)
box.pack_start(webview, True, True, 0)
box.pack_start(button, False, False, 1)
win.add(box)
# Functions
def get_element_values(self, element_name):
webview.js_run('get_checked_values("{0}")'.format(element_name))
def show_js_value(object):
print((webview.js_value))
def show_html_response(object):
print((webview.html_response))
# Signals
win.connect("delete-event", Gtk.main_quit)
button.connect("clicked", get_element_values, 'chktst')
webview.connect("js-finished", show_js_value)
#webview.connect("html-response-finished", show_html_response)
# Load html and show window
webview.show_html(html)
win.show_all()
Gtk.main()
来源：https://stackoverflow.com/questions/52870923/webkit2-and-domdocument-javascriptcore-python3