-2

I have Flask app and within the app, I have a view where I am using xlsxwriter to write and save Excel file. When I run the app locally it works perfectly. When I deploy it all the views work except the one where I am writing the Excel file, it gives me Error 500. In the logs I was that the error is that I am trying to start the file with function that is only for windows, can someone tell me how to start the file or download it? I don't need it to be stored in a database or cloud storage, just to be printed or downloaded immediately. P.s Please excuse me if I have made a mistake asking this question.

Logs:

2020-02-22T16:10:18.789403+00:00 app[web.1]: [2020-02-22 16:10:18,787] ERROR in app: Exception on /proverka [POST]
2020-02-22T16:10:18.789405+00:00 app[web.1]: Traceback (most recent call last):
2020-02-22T16:10:18.789406+00:00 app[web.1]: File "/app/.heroku/python/lib/python3.7/site-packages/flask/app.py", line 2446, in wsgi_app  
2020-02-22T16:10:18.789407+00:00 app[web.1]: response = self.full_dispatch_request()
2020-02-22T16:10:18.789408+00:00 app[web.1]: File "/app/.heroku/python/lib/python3.7/site-packages/flask/app.py", line 1951, in full_dispatch_request
2020-02-22T16:10:18.789408+00:00 app[web.1]: rv = self.handle_user_exception(e)
2020-02-22T16:10:18.789408+00:00 app[web.1]: File "/app/.heroku/python/lib/python3.7/site-packages/flask/app.py", line 1820, in handle_user_exception
2020-02-22T16:10:18.789409+00:00 app[web.1]: reraise(exc_type, exc_value, tb)
2020-02-22T16:10:18.789409+00:00 app[web.1]: File "/app/.heroku/python/lib/python3.7/site-packages/flask/_compat.py", line 39, in reraise 
2020-02-22T16:10:18.789410+00:00 app[web.1]: raise value
2020-02-22T16:10:18.789410+00:00 app[web.1]: File "/app/.heroku/python/lib/python3.7/site-packages/flask/app.py", line 1949, in full_dispatch_request
2020-02-22T16:10:18.789411+00:00 app[web.1]: rv = self.dispatch_request()
2020-02-22T16:10:18.789411+00:00 app[web.1]: File "/app/.heroku/python/lib/python3.7/site-packages/flask/app.py", line 1935, in dispatch_request
2020-02-22T16:10:18.789412+00:00 app[web.1]: return self.view_functions[rule.endpoint](**req.view_args)
2020-02-22T16:10:18.789413+00:00 app[web.1]: File "/app/app.py", line 206, in proverka
2020-02-22T16:10:18.789413+00:00 app[web.1]: os.startfile("C:\\Users\\Nenad\\Desktop\\magacin vs\\ISPRATNICI\\{}, {}.xlsx".format(s.id, s.ime))
2020-02-22T16:10:18.789414+00:00 app[web.1]: AttributeError: module 'os' has no attribute 'startfile'
2020-02-22T16:10:18.790447+00:00 app[web.1]: 10.102.224.122 - - [22/Feb/2020:16:10:18 +0000] "POST /proverka HTTP/1.1" 500 290 "https://oska-prom.herokuapp.com/proverka" "Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/79.0.3945.130 Safari/537.36"
2020-02-22T16:10:18.790269+00:00 heroku[router]: at=info method=POST path="/proverka" host=oska-prom.herokuapp.com request_id=4012bbf1-c4ec-46e9-bfd0-5d8fdb23c23d fwd="77.29.30.58" dyno=web.1 connect=0ms service=43ms status=500 bytes=470 protocol=https
2020-02-22T16:10:19.267659+00:00 heroku[router]: at=info method=GET path="/proverka" host=oska-prom.herokuapp.com request_id=ee6b17a9-a2b0-4b77-adaf-d967c48ace12 fwd="77.29.30.58" dyno=web.1 connect=0ms service=15ms status=200 bytes=2539 protocol=https
2020-02-22T16:10:19.269189+00:00 app[web.1]: 10.102.224.122 - - [22/Feb/2020:16:10:19 +0000] "GET /proverka HTTP/1.1" 200 2377 "-" "Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/79.0.3945.130 Safari/537.36"
Nenad Ristov
  • 11
  • 9
  • try csv or check this link https://flask-excel.readthedocs.io/en/latest and this post https://stackoverflow.com/questions/10434599/get-the-data-received-in-a-flask-request – Wael Almadhoun Feb 22 '20 at 16:46
  • To delete / reopen voters: OP [asked this same question again](https://stackoverflow.com/q/60382390/354577), with slightly more detail, and received an accepted answer that time. – ChrisGPT was on strike Feb 27 '20 at 16:28

1 Answers1

1

First

You're starting your app on heroku but using hardcoded pathes in your code os.startfile("C:\\Users\\Nenad\\Desktop\\magacin vs\\ISPRATNICI\\{}, {}.xlsx".format(s.id, s.ime))

Second

You're using os.startfile which is only available on windows, heroku doesn't run windows.

Third

You can't access file system on heroku anyway. Only during the deployment and even that is not enough, as everything not related to deployment will be removed at midnight.

If you really want to save xls on heroku - you'll have to rewrite your application to be "linux compatible" and consider saving your file in database.

Javed
  • 326
  • 3
  • 8
  • This is basically right, but here are a few notes: Heroku's dynos restart (and reset their filesystems) roughly once per day, but there's no guarantee that it will happen at midnight. And I probably wouldn't put Excel files into a database; a third-party object storage service like Amazon S3 or Azure Blob Storage would be a better fit. – ChrisGPT was on strike Feb 22 '20 at 20:45
  • If I change '''os.startfile''' to the correspondent function in Linux would it run then? If yes can you tell me what function it is? I don't need the file to be stored in database, just to be downloaded or printed immediately. – Nenad Ristov Feb 24 '20 at 18:54