server_example.py

from flask import Flask, make_response
app = Flask(__name__)


import matplotlib.pyplot as plt


def draw_picture():
    # Open the file with all the airports and read every line
    data = open("airports.dat", "r").readlines()
    
    # make an array to store the final data
    final_data = []
    
    # go through each row and extract the airport altitude
    for row in data:
    	row_items = row.split(",") # split by the comma
    	final_data.append(float(row_items[8]))
      
    
    num_bins = 50
    
    fig, ax = plt.subplots()
    
    # the histogram of the data
    n, bins, patches = ax.hist(final_data, num_bins, normed=0)
    
    # add labels
    ax.set_xlabel('Altitude')
    ax.set_ylabel('Number of Airports')
    ax.set_title(r'Histogram of Elevations of Airports')
    
    # Tweak spacing to prevent clipping of ylabel
    fig.tight_layout()
    return fig

@app.route("/simple.png")
def simple():
    import StringIO
    from matplotlib.backends.backend_agg import FigureCanvasAgg as FigureCanvas

    canvas=FigureCanvas(draw_picture())
    png_output = StringIO.StringIO()
    canvas.print_png(png_output)
    response=make_response(png_output.getvalue())
    response.headers['Content-Type'] = 'image/png'
    return response


if __name__ == "__main__":
    app.run()