web.py doesn't delete stop between requests

Question

Took me a very long time to figure out what the problem was, and now I don't know how to solve it.

I'm using pythonanywhere to run my web.py server

So here's the problem. The web.py instance does not stop running between server requests. Let me demonstrate what heppens because of that.

I have a list that gets populated in a loop with list.append(number) So during the first request to the server the script runs fine. list = (1, 2, 3)

However, since the web.py instance does not cease, on the second request to the server list ends up being (1, 2, 3, 1, 2, 3) and my script doesn't work.

How do I know web.py doesn't stop running between requests? When I deleted every namespace at the end of the scripts life, the second request to the server returned an error saying that 'web was not defined'

class web_serve:

def GET(self):

    data_obj = volumePit_google()
    plotter = volumePit_plot()

    data_obj.download('SPY', 2)
    data_obj.organize()

    price, volume = zip(*data_obj.data_final)
    plot_edges = data_obj.plotter_edges
    e_test = data_obj.data_ticks

    plotter.maxmin(price)
    data_obj.plotter_ticks()

    for i, tick in enumerate(data_obj.data_ticks[1:]):
        edges = [data_obj.data_ticks[i], tick]
        volume_edges = [plot_edges[i], plot_edges[i+1]]

        day_data = data_obj.data_final[edges[0]:edges[1]]
        price, volume = zip(*day_data)

        plotter.dividers(volume_edges)

        price_position = data_obj.price_action(price, [volume_edges[0], volume_edges[1]])
        plotter.subplot.plot(price_position, price, color='g', ls='-', lw='1')

        histogram = data_obj.histogram(day_data, 0)
        plotter.volume_profile(histogram, volume_edges)

    plotter.ticks([data_obj.plotter_edges, data_obj.dates, data_obj.plotter_tick_pos])

    data_stream = cStringIO.StringIO()
    plt.savefig(data_stream, bbox_inches='tight')
    data_stream.seek(0)
    return_png = base64.b64encode(data_stream.read())
    data_stream.close()

    return return_png

The variables that need clearing are within data_obj

I don't know if it's worth mentioning but both of the below classes are defined in the same file data_obj = volumePit_google() plotter = volumePit_plot()

class volumePit_google:
data = []
data_final = []

day_volume = []
data_ticks = [] #list contains indexes of the data_final separating days
dates = []

plotter_tick_pos = []
plotter_edges = [0]

def download(self, ticker, period):

Answer 1

I can't imagine why you would want the server to stop between requests. That would be extraordinarily inefficient.

You should simply avoid keeping global/module-level objects.

Edited Now you have finally posted the code to the volumePit_google class, we can see what the problem is. Anything defined at class level in Python is a class variable, shared between all members of the class. What you need instead is instance variables, which are defined each time the class is instantiated:

class volumePit_google(object):
    def __init__(self):
        self.data = []
        self.data_final = []

        self.day_volume = []
        self.data_ticks = [] #list contains indexes of the data_final separating days
        self.dates = []

        self.plotter_tick_pos = []
        self.plotter_edges = [0]