Call Python function from JavaScript code

Question

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

User · Answer

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

User · Answer

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  http   example com your webservice param1 x amp param2 y        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

User · Answer

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

User · Answer

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

User · Answer

All you need is to make an ajax request to your pythoncode  You can do this with jquery http   api jquery com jQuery ajax   or use just javascript    ajax     type   POST     url     pythoncode py     data    param  text     done function  o           do something

[javascript] Call Python function from JavaScript code

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