I'd like to call a Python function from JavaScript code, because there isn't an alternative in JavaScript for doing what I want. Is this possible? Could you adjust the below snippet to work?
JavaScript code:
var tag = document.getElementsByTagName("p")[0];
text = tag.innerHTML;
// Here I would like to call the Python interpreter with Python function
arrOfStrings = openSomehowPythonInterpreter("~/pythoncode.py", "processParagraph(text)");~/pythoncode.py contains functions using advanced libraries that don't have an easy to write equivalent in JavaScript:
import nltk # is not in JavaScript
def processParagraph(text): ... nltk calls ... return lst # returns a list of strings (will be converted to JavaScript array)6 Answers
All you need is to make an ajax request to your pythoncode. You can do this with jquery , or use just javascript
$.ajax({ type: "POST", url: "~/pythoncode.py", data: { param: text}
}).done(function( o ) { // do something
});From the document.getElementsByTagName I guess you are running the javascript in a browser.
The traditional way to expose functionality to javascript running in the browser is calling a remote URL using AJAX. The X in AJAX is for XML, but nowadays everybody uses JSON instead of XML.
For example, using jQuery you can do something like:
$.getJSON(' function(data, textStatus, jqXHR) { alert(data); }
)You will need to implement a python webservice on the server side. For simple webservices I like to use Flask.
A typical implementation looks like:
@app.route("/your/webservice")
def my_webservice(): return jsonify(result=some_function(**request.args)) You can run IronPython (kind of Python.Net) in the browser with silverlight, but I don't know if NLTK is available for IronPython.
Typically you would accomplish this using an ajax request that looks like
var xhr = new XMLHttpRequest();
xhr.open("GET", "pythoncode.py?text=" + text, true);
xhr.responseType = "JSON";
xhr.onload = function(e) { var arrOfStrings = JSON.parse(xhr.response);
}
xhr.send();Communicating through processes
Example:
Python: This python code block should return random temperatures.
# sensor.py
import random, time
while True: time.sleep(random.random() * 5) # wait 0 to 5 seconds temperature = (random.random() * 20) - 5 # -5 to 15 print(temperature, flush=True, end='')Javascript (Nodejs): Here we will need to spawn a new child process to run our python code and then get the printed output.
// temperature-listener.js
const { spawn } = require('child_process');
const temperatures = []; // Store readings
const sensor = spawn('python', ['sensor.py']);
sensor.stdout.on('data', function(data) { // convert Buffer object to Float temperatures.push(parseFloat(data)); console.log(temperatures);
});You cannot run .py files from JavaScript without the Python program like you cannot open .txt files without a text editor. But the whole thing becomes a breath with a help of a Web API Server (IIS in the example below).
Install python and create a sample file test.py
import sys # print sys.argv[0] prints test.py # print sys.argv[1] prints your_var_1 def hello(): print "Hi" + " " + sys.argv[1] if __name__ == "__main__": hello()Create a method in your Web API Server
[HttpGet] public string SayHi(string id) { string fileName = HostingEnvironment.MapPath("~/Pyphon") + "\\" + "test.py"; Process p = new Process(); p.StartInfo = new ProcessStartInfo(@"C:\Python27\python.exe", fileName + " " + id) { RedirectStandardOutput = true, UseShellExecute = false, CreateNoWindow = true }; p.Start(); return p.StandardOutput.ReadToEnd(); }And now for your JavaScript:
function processSayingHi() { var your_param = 'abc'; $.ajax({ url: '/api/your_controller_name/SayHi/' + your_param, type: 'GET', success: function (response) { console.log(response); }, error: function (error) { console.log(error); } }); }
Remember that your .py file won't run on your user's computer, but instead on the server.
0Despite what some replies and comments suggest, there are a number of ways for using Python on the front-end. For your question in particular, see this reply.
