Verify file has downloaded before continuing with script

Question

I need to ensure that a file has been downloaded before my script can continue. I have done some research on the exists() function however I cannot find an example of what I am actually trying to do.

I am attempting to download multiple files. I have a static destination for all files being downloaded. I need to ensure that the files has been successfully downloaded to the file before the script can continue. Can someone help me with an example of what that script would look like?

Here is what I am working with:

import time
import os
import glob
import os.path
from selenium.webdriver.common.action_chains import ActionChains
from selenium.common.exceptions import MoveTargetOutOfBoundsException
from selenium import webdriver
from selenium.webdriver.common.keys import Keys
from selenium.common.exceptions import NoSuchElementException
from selenium.common.exceptions import NoAlertPresentException

for x in range(1, 100):      
    while True:    
        try:
            fp = webdriver.FirefoxProfile('C:/Users/me/Documents/FirefoxProfile')
            browser = webdriver.Firefox(fp)
            browser.get('https://reportcenter.com')

            time.sleep(8)

            browser.find_element_by_id("ctl00_PlaceHolderMain_login_UserName").clear()
            browser.find_element_by_id("ctl00_PlaceHolderMain_login_UserName").send_keys("usr")
            browser.find_element_by_id("ctl00_PlaceHolderMain_login_password").clear()
            browser.find_element_by_id("ctl00_PlaceHolderMain_login_password").send_keys("pwd")
            browser.find_element_by_id("ctl00_PlaceHolderMain_login_login").click()

#gets user to reporting front end

            ReportMgr= browser.find_element_by_partial_link_text('Report Manager')
            ReportMgr.click()

            time.sleep(5)

            CustomReport= browser.find_element_by_partial_link_text('Custom Report')
            CustomReport.click()

            time.sleep(5)

            ProgramManagement= browser.find_element_by_partial_link_text('Program Management')
            ProgramManagement.click()
            ProgramManagement= browser.find_element_by_partial_link_text('Program Management').send_keys(Keys.ARROW_LEFT)

#pulls reports

            browser.find_element_by_partial_link_text('Program Management').click()
            time.sleep(60)
            browser.find_element_by_partial_link_text('Program Management').send_keys(Keys.ARROW_DOWN * x, Keys.ENTER, Keys.ENTER)
            time.sleep(180)
            browser.find_element_by_css_selector("#ctl00_PlaceHolderMain_ReportViewer1_HtmlOutputReportResults2_CSVButton_ImageAnchor > img").click()
            time.sleep(180)
            ##THIS IS WHERE I NEED TO VERIFY THAT THE REPORT HAS DOWNLOADED BEFORE I CAN CONTINUE
            browser.find_element_by_partial_link_text('Program Management').click()
            time.sleep(60)
            browser.quit()

        except:
               browser.quit()           
               continue
        else:
               break

Answer 1

One way would be to wait for a new file to appear in the targeted folder.

Usage example:

# take a snapshot of the folder
waiter = FileWaiter(r"C:\Downloads\*.pdf")

# trigger the download
browser.find_element_by_css_selector("...").click()    

# wait for a new file or timeout after 10 seconds
new_file = waiter.wait_new_file(10)

# display the new file
print new_file

Waiting class:

import os, time, glob, numbers, exceptions 

class FileWaiter:

  def __init__(self, path):
    self.path = path
    self.files = set(glob.glob(path))

  def wait_new_file(self, timeout):
    """
    Waits for a new file to be created and returns the new file path.
    """
    endtime = time.time() + timeout
    while True:
      diff_files = set(glob.glob(self.path)) - self.files
      if diff_files :
        new_file = diff_files.pop()
        try:
          os.rename(new_file, new_file)
          self.files = set(glob.glob(self.path))
          return new_file
        except :
          pass
      if time.time() > endtime:
          raise Exception("Timeout while waiting for a new file in %s" % self.path)
      time.sleep(0.1)