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Add javascript_erors.py and ondomready.py snippets (cztomczak#403)
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‎docs/Tutorial.md‎

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@@ -9,7 +9,8 @@ basics. This tutorial will discuss the three featured examples:
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[hello_world.py](../examples/hello_world.py),
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[tutorial.py](../examples/tutorial.py)
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and [screenshot.py](../examples/screenshot.py). There are many
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more examples that you can find in the [README-examples.md](../examples/README-examples.md)
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more examples that you can find in the
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[README-examples.md](../examples/README-examples.md)
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file, but these examples are out of scope for this tutorial.
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‎examples/README-examples.md‎

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@@ -4,8 +4,8 @@ Table of contents:
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* [Hello World!](#hello-world)
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* [Supported examples](#supported-examples)
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* [Featured](#featured)
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* [GUI frameworks](#gui-frameworks)
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* [Snippets](#snippets)
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* [GUI frameworks](#gui-frameworks)
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* [Build executable with PyInstaller](#build-executable-with-pyinstaller)
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* [Unit tests](#unit-tests)
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* [Other examples](#other-examples)
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discussed in great details in Tutorial in the [Off-screen rendering](../docs/Tutorial.md#off-screen-rendering)
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section.
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### Snippets
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See small code snippets that show various CEF features in the
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[examples/snippets/](snippets/) directory:
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- [javascript_bindings.py](snippets/javascript_bindings.py) - Communicate
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between Python and Javascript asynchronously using
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inter-process messaging with the use of Javascript Bindings.
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- [javascript_errors.py](snippets/javascript_errors.py) - Two ways for
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intercepting Javascript errors.
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- [mouse_clicks.py](snippets/mouse_clicks.py) - Perform mouse clicks
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and mouse movements programmatically.
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- [network_cookies.py](snippets/network_cookies.py) - Implement
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interfaces to block or allow cookies over network requests.
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- [onbeforeclose.py](snippets/onbeforeclose.py) - Implement interface
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to execute custom code before browser window closes.
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- [ondomready.py](snippets/ondomready.py) - Execute custom Python code
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on a web page as soon as DOM is ready.
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### GUI frameworks
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Examples of embedding CEF browser using various GUI frameworks:
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- [gtk2.py](gtk2.py): example for [PyGTK](http://www.pygtk.org/)
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library (GTK 2)
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- [gtk3.py](gtk3.py): example for [PyGObject / PyGI](https://wiki.gnome.org/Projects/PyGObject)
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toolkit. This example implements High DPI support on Windows.
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### Snippets
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See small code snippets that test various features in the
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[examples/snippets/](snippets/) directory:
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- [javascript_bindings.py](snippets/javascript_bindings.py) - Communicate
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between Python and Javascript asynchronously using
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inter-process messaging with the use of Javascript Bindings.
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- [mouse_clicks.py](snippets/mouse_clicks.py) - Perform mouse clicks
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and mouse movements programmatically.
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- [network_cookies.py](snippets/network_cookies.py) - Implement
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interfaces to block or allow cookies over network requests.
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- [onbeforeclose.py](snippets/onbeforeclose.py) - Implement interface
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to execute custom code before browser window closes.
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### Build executable with PyInstaller
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- [PyInstaller example](pyinstaller/README-pyinstaller.md):

‎examples/snippets/javascript_bindings.py‎

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@@ -17,7 +17,6 @@
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</style>
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<script>
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function print(msg) {
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console.log(msg+" [JS]");
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document.getElementById("console").innerHTML += msg+"<br>";
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}
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function js_function(value) {
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def main():
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cef.Initialize()
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browser = cef.CreateBrowserSync(url=cef.GetDataUrl(g_htmlcode),
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window_title="OnBeforeClose")
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window_title="Javascript Bindings")
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browser.SetClientHandler(LifespanHandler())
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bindings = cef.JavascriptBindings()
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bindings.SetFunction("py_function", py_function)

‎examples/snippets/javascript_errors.py‎

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"""
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Two ways for intercepting Javascript errors:
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1. window.onerror event in Javascript
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2. DisplayHandler.OnConsoleMessage in Python
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"""
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from cefpython3 import cefpython as cef
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g_htmlcode = """
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<!doctype html>
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<html>
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<head>
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<style>
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body, html {
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font-family: Arial;
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font-size: 11pt;
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}
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</style>
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<script>
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function print(msg) {
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document.getElementById("console").innerHTML += msg+"<br>";
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}
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window.onerror = function(message, source, lineno, colno, error) {
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print("[JS:window.onerror] "+error+" (line "+lineno+")");
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// Return false so that default event handler is fired and
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// OnConsoleMessage can also intercept this error.
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return false;
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};
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window.onload = function() {
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forceError();
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};
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</script>
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</head>
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<body>
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<h1>Javascript Errors</h1>
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<div id=console></div>
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</body>
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</html>
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"""
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def main():
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cef.Initialize()
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browser = cef.CreateBrowserSync(url=cef.GetDataUrl(g_htmlcode),
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window_title="Javascript Errors")
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browser.SetClientHandler(DisplayHandler())
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cef.MessageLoop()
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cef.Shutdown()
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class DisplayHandler(object):
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def OnConsoleMessage(self, browser, message, line, **_):
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if "error" in message.lower() or "uncaught" in message.lower():
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logmsg = "[Py:OnConsoleMessage] {message} (line {line})" \
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.format(message=message, line=line)
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print(logmsg)
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browser.ExecuteFunction("print", logmsg)
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if __name__ == '__main__':
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main()

‎examples/snippets/ondomready.py‎

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"""
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Execute custom Python code on a web page as soon as DOM is ready.
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Implements a custom "_OnDomReady" event in the LifespanHandler object.
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"""
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from cefpython3 import cefpython as cef
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def main():
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cef.Initialize()
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browser = cef.CreateBrowserSync(url="https://www.google.com/",
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window_title="_OnDomReady event")
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lifespan_handler = LifespanHandler(browser)
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browser.SetClientHandler(lifespan_handler)
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bindings = cef.JavascriptBindings()
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bindings.SetFunction("LifespanHandler_OnDomReady",
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lifespan_handler["_OnDomReady"])
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browser.SetJavascriptBindings(bindings)
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cef.MessageLoop()
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del lifespan_handler
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del browser
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cef.Shutdown()
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class LifespanHandler(object):
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def __init__(self, browser):
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self.browser = browser
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def __getitem__(self, key):
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return getattr(self, key)
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def OnLoadStart(self, browser, **_):
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browser.ExecuteJavascript("""
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if (document.readyState === "complete") {
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LifespanHandler_OnDomReady();
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} else {
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document.addEventListener("DOMContentLoaded", function() {
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LifespanHandler_OnDomReady();
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});
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}
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""")
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def _OnDomReady(self):
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print("DOM is ready!")
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self.browser.ExecuteFunction("alert",
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"Message from Python: DOM is ready!")
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if __name__ == '__main__':
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main()

‎src/cef_v59..v66_changes.txt‎

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@@ -83,6 +83,8 @@ NEW FEATURES
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+ network_cookies.py
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+ mouse_clicks.py
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+ javascript_bindings.py
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+ javascript_errors.py
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+ ondomready.py
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+ cef.GetDataUrl
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internal/cef_types.h

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