Pasted images have wrong repo-based URL

[silverwind]

• Gitea version (or commit ref): 1.15.0+dev-165-g5e85cdad2
• Can you reproduce the bug at https://try.gitea.io: https://try.gitea.io/silverwind/symlink-test/issues/6#issuecomment-77653

Description

Pasting an image results in it being linked on the wrong URL:

https://try.gitea.io/silverwind/symlink-test/attachments/265b512e-f7a7-46a0-922c-7afe1bc0f530

But it should be

https://try.gitea.io/attachments/265b512e-f7a7-46a0-922c-7afe1bc0f530

Markdown and HTML:

![image](/attachments/265b512e-f7a7-46a0-922c-7afe1bc0f530)

<a href="/silverwind/symlink-test/attachments/265b512e-f7a7-46a0-922c-7afe1bc0f530" rel="nofollow"><img src="/silverwind/symlink-test/attachments/265b512e-f7a7-46a0-922c-7afe1bc0f530" alt="image"></a>

Image attachments via dropzone are not affected, see comment below.

[silverwind]

Possible regression from #15088.

[silverwind]

I think we need to either generate absolute URLs (like github) or add something else on the produced link that marks it as an server attachment instead of a repo-relative file. Absolute URLs of course won't be portable.

[lunny]

how about /attachments/265b512e-f7a7-46a0-922c-7afe1bc0f530 means it's an absolute path to the gitea's root url.
attachments/265b512e-f7a7-46a0-922c-7afe1bc0f530 means it's a relative path to the repository or current path.

[silverwind]

Don't think we can distinguish based on leading characters, GitHub does support all three variants in repo files but notable does not support repo-relative images in issue comments at all.

https://github.com/silverwind/gitea/blob/e71060b08986d747c57cb07cee9dfc53593579a8/test.md

Test code:

![image](./public/img/gitea.svg)

![image](/public/img/gitea.svg)

![image](public/img/gitea.svg)

[silverwind]

I guess what we could do is check for those /attachments/<id> links and first check if there is an attachments with that id present, otherwise fallback to repo-relative. Probably the only way to keep existing links working. Or just disable repo-relative links in comments like GitHub does, I barely see a use for them.

[lunny]

Or we can add a new route /:owner/:repo/attachments/<id>

[silverwind]

I'd be fine with a /:owner/:repo/attachments/<exact-uuidv4> route (e.g. regex route). Chances would be pretty low that someone has such files in a repo.

[lunny]

Use a uuid rather than id is better.

[yerz]

I upgraded Gitea，Then all the pictures submitted in the issue of my project became like this, and the inaccessible URL was changed

Before the upgrade [Normal preview]
https://my domain/attachments/2622ca24-5a9a-45db-a6ff-aed00717123c

after upgrade [Unable to preview]
https://my domain/organization/project/attachments/2622ca24-5a9a-45db-a6ff-aed00717123c

The pictures of my whole issue can no longer be viewed. 😭

[wULLSnpAXbWZGYDYyhWTKKspEQoaYxXyhoisqHf]

this is great, just today I went ahead and hotfixed this on my proxy (nginx string rewrites), now I don't need it anymore.
thanks for the fix y'all! 🚀