How to pass a javascript array to a python script using flask [using flask example]
ajax, arrays, flask, javascript, python
Solution
Here is another way to pass JS Array to python :
JS Side:
$.getJSON($SCRIPT_ROOT + '/_array2python', {
wordlist: JSON.stringify(list)
}, function(data){
console.log(data.result)
$( "#result" ).text(data.result);
});
Python Side:
import json
@app.route('/_array2python')
def array2python():
wordlist = json.loads(request.args.get('wordlist'))
# do some stuff
return jsonify(result=wordlist)
As far as I know, strings are the only way to pass array from client to server.
Problem
I am trying to get the flask/jquery/ajax example working for my specific case, but I am coming up short every time. I am aware this sort of question has been asked several times, but the answers do not help me (Yes, I am new to this). The example passes a string from javascript to python. I would like to pass an array over. The web suggests that this is possible. Here is what I have: HTML/Flask Template: ``` {% extends "layout.html" %} {% block title %}Test{% endblock %} {% block content %} <div> <h1>Flask Jquery Test</h1> <div> <input type="button" value="Transfer" id="button" /> </div> <div> Wordlist<br /> <select multiple="multiple" id="wordlist" size="5"> <option>Volvo</option> <option>Audi</option> <option>BMW</option> <option>Mercedes</option> <option>Toyota</option> </select> <span id="result"></span> </div> </div> {% endblock %} ``` JS Script: ``` $(document).ready(function() { $("#button").bind('click', function(){ //Get all words from list var list = []; $("#wordlist option").each(function(){ list.push($(this).val()); }); //var list = $( "#wordlist option" ).val(); console.log(list); $.getJSON($SCRIPT_ROOT + '/_array2python', { wordlist: list.toString() }, function(data){ console.log(data.result) $( "#result" ).text(data.result); }); return false; }); }); ``` Python: ``` @app.route('/') def start_page(): return render_template('index.html') @app.route('/_array2python') def array2python(): wordlist = request.args.get('wordlist', []) return jsonify(result=wordlist) @app.errorhandler(404) def page_not_found(e): """Return a custom 404 error.""" return 'Sorry, nothing at this URL.', 404 ``` Now, when passing into the `list` variable a string (e.g. `var list = $( "#wordlist option" ).val();` ), this code works just fine. However, when trying it with an array, it only ever passes the backup value (i.e. `[]`). Does this mean, I can only pass strings to python? How would I best pass a javascript array to python? Thanks everyone for your help! P.S. Maybe it is important to mention. I am using google app engine to host this code. ================================================================================= FYI, these are the SO sites that I tried to follow and they did not help me: Passing Javascript Array to Flask (Excellent and very detailed answer, but can't get it to work) Passing data from javascript into Flask Return data from html/js to python