Check for error before writing new file in client.Store()

[chetanyakan]

Summary
Prevent creation of a corrupted file if the file conversion fails.

Explain the motivation for making this change. What existing problem does the pull request solve?

I tried converting a ppt file to pdf. Due to some memory or time issue (I wasn't able to figure out the cause), the file failed to convert and a corrupted file of ~57B was written instead, which could not be opened in a PDF viewer.

For reference, the following error was in the Gotenberg logs:

code=500, message=unoconv: non-zero exit code: exit status 6

I expected the client.Store() method to return an error instead of writing a corrupted file.

Test plan (required)

Demonstrate the code is solid. Example: The exact commands you ran and their output.

Checklist

• Have you followed the guidelines in our CONTRIBUTING guide?
• Have you lint your code locally prior to submission (make lint)?
• Have you written new tests for your core changes, as applicable?
• Have you successfully ran tests with your changes locally (make tests)?
• I have squashed any insignificant commits
• This change has comments for package types, values, functions, and non-obvious lines of code

[gulien]

Hello @chetanyakan

Thank you for this PR.

I expected the client.Store() method to return an error instead of writing a corrupted file.

Indeed, I was expected the line resp, err := c.Post(req) to return an error if status != 200 (I'm not a familiar with Golang HTTP client..).

Concerning your conversion issue, did you use the latest version of Gotenberg?

[gulien]

Why not simply check res.StatutsCode != http.StatusOK?

[chetanyakan]

Indeed I was not aware whether gotenberg returns any non-200 (2XX) status codes upon successful conversion to pdf.
If the status code is expected to be 200 always, you can let me know and I can make the required change.

[gulien]

Yes the expected status code is always excepted to be 200 😄

[chetanyakan]

Done.

[chetanyakan]

Regarding my issue, I was using gotenberg v4.
It was likely some memory-related issue as although I was able to repetedly see the issue before, I was able to successfully convert the same file afterward with same version of gotenberg.

[gulien]

It was likely some memory-related

Version 6 should behave way better on that issue 👍

[gulien]

Thank you 😄 👍