Can't access Javascript object from C# (CefSharp) - javascript

My setup is really simple, in C# (WPF) I have a WebView, that loads my HTML page.
Now I want to have a two way communication between the two.
Calling C# from Javascript works totally fine for me, using RegisterJsObject.
Now I try to execute Javascript from C#, using ExecuteScript.
As long as I only use plain Javascript, such as
ExecuteScript("document.getElementById('test').innerHTML='test'")</code>
it works perfectly fine.
But when I try to access functions I created in Javascript, it fails to execute them.
Javascript:
function test(param) {
alert(param);
}
C#:
webView.ExecuteScript("test('123')");

This is how I invoke my Javascript function from my WPF C# application using a WebView:
this.webView.InvokeScript("test", new object[] { "('123')" });
For a more detailed explanation go to this web site: http://www.dotnetfunda.com/articles/show/840/working-with-webbrowser-in-wpf
Hope this is the answer that will help you.

I am not sure, what my actual problem was.
I got it to work by starting from scratch again, starting with basic calls, then getting closer to the actual code I want to execute, and now it somehow works.

Related

Safely running javascript code in java

I am sorry if this is an unclear title because I do not know all the terminology, so please bear with me.
So I am trying to create a controlled environment to run any JavaScript code in a Java application. Note: code is created by a user so I have to block/prevent code that is specifically trying to access/modify java variables that are not supposed to be at reach. (preferably by throwing a compile error for user feedback)
Edit 1: By the way I tried to use Rhino and Nashorn.
Here is a simple example.
public class ScriptRunner{
public Foo foo=new Foo();
//this is not supposed to be accessed by the script
public int money=0;
public Object run(){
return compiler.compile(STRING START (obtained from a file)
function main(someObject){
//this is not allowed
someObject.money=10000000000000000000000;
//or this
var someBlacklistedJavaObject=.....
someBlacklistedJavaObject.someFuncton();
//but this is allowed
someObject.foo.name="Bob";
return someObject.foo.someFunction();
}
STRING END).run("main",this);
}
}
Also I am not sure if this would be one of the possible solution but I can't use the built in java security class due to some unreachable code implementing it and not allowing to set the security object to anything else.
What comes to my mind is that an easy implementation of this would be to create wrapper Java classes in some package. Than check if a java object in script does not have that path and throw an error. But the problem is that I have no idea how to do that.
Here is a simple visualization of what I am trying to do.
Edit 2: It is desirable to maintain a low Java compatibility profile, but it's not 100% necessary.
Use a ClassFilter with Nashorn (note: requires Java >= 1.8.0_40)

Can I use jQuery.post() with LiveServerTestCase?

I'm writing a test using a LiveServerTestCase, django-casper, and casperjs for a view that includes javascript. Half way through a client side script I have a jQuery.post(url, callback_function(r){}) line.
When callback_function is called during a test r is null. However, when I run the application normally and step through the same javascript when callback_function is called r has the expected value.
This makes me think that there is a detail about LiveServerTestCase I'm missing to get jQuery.post to work with it. Can anybody please shed light on what I should do next to debug this problem?
I'm guessing it's because the static files aren't around. In Django 1.7, LiveServerTestCase no longer supported serving up the static files. It was moved into testing.StaticLiveServerTestCase
Try changing your test classes to subclass StaticLiveServerTestCase.

Export Flash parameters to JavaScript

I'm trying to pass parameters from Flash (as 3.0) to JavaScript.
Tried all methods I found in via. Google, as:
ExternalInterface.addCallback ("fonts", recieveFromJS);
Always one and the same problem; when I try to call the fonts () swfobject, JavaScript gives the error that the method doesn't exist.
Assuming your javascript code does not have a syntax error somewhere, this usually happens because of jquery (or some other js bundle) is stepping on your code. Try using a test page with just the javascript you need, removing all other code and header entries. If it works, then add scripts and links back, one at a time, and you will find which code is breaking it. If it does not work even in your test page, then you have a code/syntax/logic problem with the snippet of code you are working with. If you still have a problem with a code snippet, post it here and I or someone will surely help debug it for you.

Strange Javascript/vbscript behavior when opening file from browser

An old web application I recently have to work with is having an issue. There is an input element that contains the following:
onClick="javascript:Run('**SomeFilePath.mdb**');"
What this is supposed to do is open a users respective .mdb file.
First off, there is no javascript Run function defined anywhere. I searched online because I thought maybe it's an old javascript built-in, but I couldn't find anything.
Second off, there IS a vbscript Run() function, that implements the described behavior, defined in the source code, but as far as I know javascript can't call that other than via ajax, which as you can see isn't what is happening.
The strange part is this works for some users!
If anyone could shed some light as to why I'd appreciate it!
EDIT: The only browser I'm dealing with is IE. I know there is an active-x way to open a file, which is what the vbscript Run() function I mentioned above is using.
Update: So after more investigation/research, it would seem like when IE doesn't find the javascript Run() function it defaults to the vbscript Run() function that IS defined. However this only occurs on some versions of IE. Can anyone confirm this behavior?
Research links:
Comment referring to how IE defaults w/ scripting
Msdn article about using both script types in same page
Yes, you can run vbscript from javascript and vice-versa, i do it sometimes when one language doesn't support something the other does.
You can indicate in your script which is the default language in case you don't specify it like .
You can also specify it while calling the function like vbscript:functionname("..") or javascript:functionname("..")
As you noticed there are cases where the browser gets confused and doesn't find the function because he searches/executes the function in the wrong language.
This behavior is influenced i suppose by version also but surely by in which order the logic flows in your script, if the browser first executes a javascript he tends to go further in this language in case of doubt.
So to evade this
don't mix the two unless realy necessary, translate your vbscript function in javascript)
try to always use javascript, vbscript is less good at handling DOM etc
in case they are mixed, specify the correct scriptlanguage when you call a function
when opening a script tag, also give the correct language like or
So, specific, to solve your problem translate the vbsripts function to javascript and if not possible, call your function like onClick="vbscript:Run('**SomeFilePath.mdb**')"

Silverlight 4 MVVM: Call Javascript function from viewmodel

we have developed an Intranet Management Application with Silverlight 4. We have been asked to add the functionality to call a remote desktop tool which is installed on clients using the Intranet SL App. In an earlier version of the tool written in ASP.NET we just added a Javascript function to the aspx page like this:
function RunShellCommand()
{
var launcher = new ActiveXObject("WScript.Shell");
launcher.Run("mstsc.exe");
}
and called it from ASP.NET.
Now it's clear that SL4 is running in a sandbox and that I cant use the AutomationFactory to create a WScript.Shell object (out of browser mode is not an option).
I thought I could circle around the problem by, again, adding the RunShellCommand javascript method in the aspx page where the SL4 control is hosted and call it via
HtmlPage.RegisterScriptableObject("Page", this);
HtmlPage.Window.Invoke("RunShellCommand", "dummydata");
from my ViewModel. When I run the Application the debugger just skips the RegisterScriptableObject method and quits. Nothing happens.
My question is if am doing something wrong or if this just wont work this way.
Is it possible that I cant do a RegisterScriptableObject from a viewmodel?
EDIT: When I explicitly put a try, catch block around the two methods I get an ArgumentException from the first method stating that the current instance has no scriptable members. When I delete the first method and only run the Invoke, I get a browser error stating that the automation server cant create the object. So is there really no way (except OOB mode) to do this?
Yes, the explanation is correct: you should add at least one method with the ScriptableMember attribute in order that you can use the RegisterScriptableObjectmethod. But it is used only for calling C#-methods from JavaScript.
As far as I see, you want to do the opposite: to call JavaScript code from the Silverlight application. Then you need only one line:
HtmlPage.Window.Invoke("RunShellCommand");
The error automation server cant create the object has nothing to do with Silverlight. I'm sure that if you call the JS function directly - the error will remain.
According to the internet, the reason might be not installed Microsoft Windows Script. Or it is because of security restrictions of the browser.

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