Invalid DOI should not show "Connection error"

[koppor]

JabRef version

Latest development branch build (please note build date below)

Operating system

Windows

Details on version and operating system

Windows 10

Checked with the latest development build

• I made a backup of my libraries before testing the latest development version.
• I have tested the latest development version and the problem persists

Steps to reproduce the behaviour

1. Open https://link.springer.com/book/10.1007/978-3-319-47590-5
2. Download PDF ("Download book PDF")
3. Go to page 207
4. Select and copy the DOI:
   
5. Open "New entry dialog" and paste DOI:
   
6. See the question mark at the end
7. Click "Generate"
8. Result:
   

Expected behavior:

• The invalid character at the end should be removed internally
• The DOI data should be fetched

Appendix

No response

[TheDeveloperDino]

Hello, is this issue free? I can work on this issue.

[koppor]

Sure! Go ahead!

[koppor]

@TheDeveloperDino You can to test-driven development. A start can be #8124. I think, one should add test cases to org.jabref.model.entry.identifier.DOITest and then work on org.jabref.model.entry.identifier.DOI.

[TheDeveloperDino]

Okey.

[mrcstan]

@TheDeveloperDino, are you still working on this? @koppor , I tried to copy and paste the DOI as described above in Windows 10 but there is no such special character at the end, and no error result. However, I could produce the error if I use invalid characters like question mark at the end of the DOI. I would like to re-define this issue as one caused by any trailing invalid characters at the end of the DOI, and I would like to volunteer to fix it if @TheDeveloperDino is no longer working on it

[jiezheng5]

Hi,

I am a cs student, I repeated the issue in both Windows 10 and Linux Ubuntn OS 20.04. I fixed this issue by adding a method to automatically remove non-valid characters at the end of DOI string and let the DOI constructor call this method. I already verified the solution using both Windows 10 and Linux. I also wrote a ParameterizedTest for the method I created. I just submitted a PR (#8215) for review.

[mrcstan]

@jiezheng5, this is not really in the spirit of open source contribution. You requested to work on this issue after me and we have not heard from @TheDeveloperDino. I have also started working on the issue.

[jiezheng5]

@jiezheng5, this is not really in the spirit of open source contribution. You requested to work on this issue after me and we have not heard from @TheDeveloperDino. I have also started working on the issue.

I actually started working on this issue 2 weeks ago. Then I saw your request, I thought maybe I should also post my progress. Do we have to first get permission before we can work on the open issues? This is my first time contributing to open source, I am sorry that if I have done something wrong.

[koppor]

Example DOI for this behavior: 10.3218/3846-0. It is a valid DOI string - but not not found on doi org: https://doi.org/10.3218/3846-0 returns 404.

When a user fetches the DOI data, "Connection error" is returned. The improved implementation should check for 404 and handle that as "No DOI data existing".

Side note: The DOI is listed at https://vdf.ch/studienarbeiten-e-book.html - and thus users may think, it is a valid one. However, the publisher seems not to have registered it at the official DOI registry.

[koppor]

I fixed this issue by adding a method to automatically remove non-valid characters at the end of DOI string

@mrcstan Could you add a test case to org.jabref.model.entry.identifier.DOITest? I think, the solution is found by working on org.jabref.model.entry.identifier.DOI#DOI_EXP, which seems to include more characters than needed in the resulting DOI?