Flask应用程序可在本地平稳运行，但在Heroku上部署时会出错 [英] Flask app runs smoothly locally but getting error when deployed on Heroku

问题描述

我有Flask应用程序，并且在该应用程序中，我有一个视图，该视图用于使用 xlsxwriter 编写和保存 Excel 文件.当我在本地运行该应用程序时，它可以完美运行.当我部署它时，除我在其中写入Excel文件的视图外，所有视图均有效，它给了我错误500..在日志中，我的错误是我试图使用以下命令启动文件仅适用于Windows的功能，有人可以告诉我如何启动文件或下载文件吗?我不需要将其存储在数据库或云存储中，只需立即打印或下载即可.附言:如果我在问这个问题时犯了一个错误，请原谅.

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.

日志:

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"

推荐答案

第一

您要在heroku上启动您的应用程序，但在代码中使用硬编码路径 os.startfile("C:\\Users\\Nenad\\Desktop\\magacin vs\\ISPRATNICI\\{}, {}.xlsx".format(s.id, s.ime))

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))

第二

您使用的os.startfile仅在Windows上可用，heroku不能运行Windows.

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

第三

无论如何，您都无法访问heroku上的文件系统.仅在部署期间，这还不够，因为与部署无关的所有内容都将在午夜删除.

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.

如果您真的想将xls保存在heroku上，则必须重写您的应用程序以使其与"linux兼容"，并考虑将文件保存在数据库中.

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.

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