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I am trying to develop a small app which will basically plot some graphs based on set of data user provided or requested. The process_order function should be run concurrent different set of data. For some reason I get only the first graph not the second and successive one. I have opened a different browser session with different user got the same result.

Example I tried to open a browser one from IE and another one from Chrome with logged in as user1 with set of 5 inputs - in IE (Expected 5 graphs) and as user2 with set of 20 input - in Chrome (Expected 20 Graphs) I was expecting 2 browser window with 5 graphs from one and 20 graphs from second window:

I am new to python and flask apologies if its something have already asked/answered in different questions

app = Flask(__name__)
plot = None
my_session = None
session_id = None

@app.route('/')
def home():
    if not session.get('logged_in'):
        return render_template('login.html')
    else:
        return render_template('template.html')

@app.route('/login', methods=['POST'])
def do_admin_login():

    if request.form['password'] == 'password' and request.form['username'] in 'admin' :
        session['logged_in'] = True
        my_session = Bot(request.form['username'])
        my_session.session_id = request.form['username']
        session['user'] = request.form['username']
        return render_template('template.html')
    else:
        flash('wrong password!')
    return home()

@app.route("/ask", methods=['POST','GET'])
def ask():

    string = str(request.form['message'])

    res = my_session.process(string)
    return jsonify({'status':'OK','answer':bot_res})


class Bot():
    #Define user level 
    def __init__(self,session_id):
      self.return_string = ""
      self.session_id = session_id

    def process(self, string):
        self.session_id = session['user']
        self.string = string
        self.return_string = self.process_order() #  This method I would like to execute as concurrent at the same time for multiple users/session with different set ot data
        return self.return_string

    def process_order(self):

        self.plot = Plot()
        self.plot.global_url = range(5)
        self.i = 0
        self.inputs = [] #tuples
        self.number = range(5)

        self.url_values = zip(self.number,self.inputs)

        self.pool = Pool()
        self.func = partial(self.plot.do_plot,self.var1)
        self.pool.map(self.func,self.url_values)
        self.pool.close()
        self.pool.join()

        process_confirmation = "Your request is complete"
        return process_confirmation


class Plot():

    def __init__(self):
        pass
    def do_plot(self, var1):

        self.number, self.url = plot_values
        self.var1 = var1

        fig = plt.figure(self.number)
        self.line = str(self.url[1])

        self.res  = urllib.request.urlopen(self.line)
        plt.imshow(plt.imread(self.res))

        self.file_name = "%03d.png"%(self.number,)
        plt.savefig(self.file_name)

        plt.close()

if __name__ == "__main__":
    session_id = None
    app.secret_key = os.urandom(12)
    my_session = Bot(session_id)
    app.run(host='0.0.0.0', port=80)
user8781522
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1 Answers1

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If the problem you are having is that individual requests take a long time, then your problem might stem from using flasks builtin server.

You can try deploying your app with gevent: http://flask.pocoo.org/docs/1.0/deploying/wsgi-standalone/#gevent

Jonah
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    No. If I were running request one at a time I am able to get the response each of them took less than 15 sec or so. The problem I see it or think while the first request is in progress the second request data some where overlapping with first and so resulted graph. I just need some extra eye or direction whether if I am using class instance variables in a proper way it should. Thanks for your inputs – user8781522 Jun 24 '18 at 23:06