Develop Reference

Call JavaScript (3rd party library) from Python

I've already searched quite a bit but came to now clear conclusion as some projects (pyv8) seem to be dead and I'm not sure if that is suitable at all. The 3rd part lib requires a DOM, eg. a container element in which it runs. It also uses web assembly and in general is pretty heavy.
Not sure if libs like pyv8 would actually be suitable for that. Other approach would be to go with selenium and headless chrome or a local node.js service but both of these sound very heavy. Oh, and the lib must work in windows as that's simply company policy, windows servers so PyMiniRacer is out.
What are my other options?

Consider taking a look at this post: How do I call a Javascript function from Python?.
However, if your objective is to access JS code in a webpage for reasons such as webscraping, you could also consider using selenium webdriver + python to do so. Take a look at this medium.com post: How to Run JavaScript in Python | Web Scraping | Web Testing
Other Resources:
https://www.quora.com/How-do-we-use-JavaScript-with-Python
Python to JS: https://pypi.org/project/javascripthon/
P.S: I am not sure if this would help you. There is another library (PyExecJS) which is maintained no longer; but I think you have looked it up already.

How to make Python to be Client-Side?

I know that Python can be a server-side language but is there a way to make python act like a client side language (like javascript) i just want to try it out if its possible thank you

You can compile your python to javascript with Pyjs.
Note that if you use Skulpt, Skulpt will NOT let you create full websites or actual javascript code that can run inside browsers. For this, you must use Pyjs. Pyjs essentially transforms your Python code into actual Javascript, so you can run the resulting Javascript in any browser, or host it as a website.

Try http://www.skulpt.org/ it is an entirely in the browser implementation of Python.

Or you could try this: http://pypyjs.org/.
It uses the PyPy python interpreter, compiled for the web via emscripten, with a custom JIT backend that emits asm.js code at runtime.

I think you want online python compiler to test the code/snippet that run on browser, try repl.it

I am guessing you know python and want everything to be in python. Well dont do it. Seriously dont even use that skulpt solution that was posted. Not because it wouldnt work. Its more because browsers only understand Javascript as a front end program. No other language is understood. If you understand python, using javascript should be a piece of cake and you might as well start that. If you really want to use python, atleast transpile into javascript using http://pyjs.org/

Pyodide gives you a full, standard Python interpreter that runs
entirely in the browser, with full access to the browser’s Web APIs.
article
https://hacks.mozilla.org/2019/04/pyodide-bringing-the-scientific-python-stack-to-the-browser/
download
https://github.com/iodide-project/pyodide

Calling C++ from JavaScript / HTML using GTK+ Webkit Webview (and Qt WebKit bridge)

I am currently evaluating different approaches / solutions to call C++ functions from JavaScript code embedded in an HTML page. The application must be run on Ubuntu Server 12.04 LTS.
I am not an expert in Linux based development. This is the first time I am trying to work on something to interface between JavaScript and C++ code.
The C++ code basically resides in the .so files ( dynamic libraries) that would provide interface methods to access certain hardware and file system. The GUI needs to be in HTML and I am searching for different solutions that are possible that can call C++ from HTML. I searched and ended up deciding to try 2 approaches, both using the WebKit engine.
Approach 1: Using Qt 5.0.2 Webkit Bridge - the WebView control
The GUI framework will be on Qt framework, the main application window will contain a webview control that would run an HTML code which in turn contains the JavaScript code.
The interface between Web page and C++ is done using the addToJavaScriptWindowObject() function.
I created a sample application and tested this solution and it seems to works fine.
Approach 2: Using GTK+ WebKit WebView
I downloaded and installed the GTK 3.0 library.
I got the webkitgtk 2.0.1 and have installed it.
I have created a test application with GTK without webkit, it works well.
I am trying to create a webkit webview control using GTK.
When trying my Approach 1 with Qt, there was quite a good set of documentation and samples to do what I wanted to. But after starting with Approach 2 using GTK+, I feel am moving slower comparitively. I personally feel that the documentation part is not that straight forward for the kind of application I am trying to develop.
Other Approaches:
I also want to try to check if either using Applets (to call the .so files directly) or using the V8 JavaScript engine to interface between JavaScript and C++ are viable options(https://code.google.com/p/v8/)
I have tried the following resources:
http://webkitgtk.org/
http://www.webkit.org/
https://live.gnome.org/WebKitGtk/ProgrammingGuide/Tutorial
I want to know how exactly to do this interface part of calling a C++ functions (in .so files) when a button is clicked in a HTML web page containing JavaScript. What kind of signal am I supposed to look for. If I am using a WebkitWebview control, how do I map a button click to a c++ function?
Can someone point me to the right direction?
I would really appreciate your time and knowledge.
Regards.

Webkit GTK 2 changed significantly in terms of API's. So I am not sure if this will work with Webkit GTK 2. However this will definitely work in Webkit GTK 1.* versions. Don't know anything about QT.
For your need of connecting html view with C/C++ side of the world, you can use two approaches. Please take a look at function webkit_dom_event_target_add_event_listener. There is example at https://live.gnome.org/WebKitGtk/ProgrammingGuide/Cookbook
Another approach you can take is to use alert on click of the button and send a string as information. On C side, you can hookup the alert listener and parse the message and decide what needs to be done. I have written lot of code in python which takes this approach since call mentioned above is not exposed to python.
I agree documentation is bit sparse for webkit gtk. However if you know how you can acomplish something in javascript, usually you can map the javascript DOM management and event calls to C side. This includes generating elements dynamically, managing events such onclick etc. You just have to dig through the header files and find matching call.

If you need to use C++ code or native applications in your web application you can try to create a service over the C++ code and access it throught a REST (for example) API.
You can use a common web application framework (Spring/Java, Django/Python, etc.) to develop your web application and use Apache Thrift to interface your library.

the best solution for you is g-xml it is a good solution by GAMA but sorry it is not free.

Javascript C++ binding?

I have some C++ code that I want to expose to client side of a web app. Ideally, I want to write Javascript wrapper objects for my C++ classes so that I can use them clientside.
Has this been done before?. Does anyone have a link to show how this may be achieved?

There is a library to convert C++ code to javascript, it might help:
emscripten

Libjspp C++ template based wrapper for embedding and extending Javascript engine spidermonkey 1 . 8 . 5 and more
SpiderMonkey? is Mozilla Project's Javascript/ECMAScript engine.
Libjspp allows C++ developers to embed SpiderMonkey? simply and easily into their applications. Libjspp allows to run multiple Javascript Engines within same process which suits one engine per thread para dime which is helpful in achieving true parallisim. Also Libjspp no way stops user from running multiple threads within engine.
http://code.google.com/p/libjspp/

I guess that RPC is what you want. You'll need to wrap your functions on the server side using some sort of framework. I've not yet used it, but this one looks promising.
On the client side you use proxy objects to dispatch the function calls. The communication is handled usually either via XML-RPC or JSON-RPC. I used this client side framework and was quite content but I'm sure you'll find many others.

This is an old topi, however, I was in the exact situation right now, and all of the solutions I found on the net complicated or outdated.
Recently, I ran across a library which supports V8 engine (including the new isolation API, which makes 90% of the libraries I found outdated) and provides great exposure and interaction API.
https://github.com/QuartzTechnologies/v8bridge
I hope that my solution will help anybody.

There's a relatively new library for doing this called nbind. Maybe that would suit you? It looks very good to me, and I'm just about to start using it.

I think you want a C++ JSON parser. You should be able to find one here http://www.json.org/. It may not do all you want because it just serializes and deserializes C++ objects without any behavior, but it should be good enough. See https://stackoverflow.com/questions/245973/whats-the-best-c-json-parser for some discussion.

If the C++ code has to be on the client, then there is no simple way to do this for a web app. A solution may involve coding plugins for the browsers you want to support, which may then be accessed from javascript code.
If, for example, you need this for a client application, that is another case. Such a thing has been done and involves linking your application to (or running from outside) with for example chromium library, or any other javascript execution engine. That way you can create bindings to C++ classes and use such objects from javascript and vice-versa. Note that this is also not a trivial solution and may be a big effort to implement (also requires additional resources).

You could for example wrap the C++ classes in PHP or Python, and then implement an API over HTTP to access the required functions.
Or if you insist on exposing the functions as JavaScript you could try using Node.js, and create an C++ add-on to wrap you classes. See the Node.js documentation here: http://nodejs.org/api/addons.html#addons_wrapping_c_objects
But either way, I don't think avoid creating some sort of API (HTTP SOAP, XML RPC) to access the functions on your server.

Though QML is not exactly Javascript, Qt is not plain C++, but what they do together seem just like what you need

how to set up a simple browser that support javascript?

I would like to setup a simple web browser that download a html page , parse it, generate a dom and execute the javascript code. I would like to know if there is a simple project(so not firefox which is good but too big to just understand this piece of logic) showing if it is the right way to handle this or someone to explain me if i am missing something. No particular language( but preferably be python, c#/c++/c ). I am stuck now at integrating the javascript engine, i don't know what to do.
Thx

I don't think its easy to pull off a javascript engine on your own. You could however use an open source engine (like WebKit's JS engine for example) and integrate it in your project.
More Infos:
http://www.webkit.org

google chrome is open source too with a neat javascript engine v8.
http://code.google.com/chromium/
http://code.google.com/p/v8/
another way could be nodejs. it's server side javascript using the v8 engine. so there is no rendering, just pure javascript. maybe thats enough if you do not need the rendering.
http://nodejs.org/

You might want to use the WebBrowser class from .NET for that purpose.
http://msdn.microsoft.com/en-us/library/system.windows.forms.webbrowser.aspx