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Possible bug corrupting file names with certain unicode code points

An rclone user has discovered that sometimes file names appear to get corrupted.

See this rclone issue for full details.

I managed to reproduce this and capture an HTTP transaction.

First here is uploading a 0 length file named "Русский.txt"

2019/10/10 12:40:16 DEBUG : HTTP REQUEST (req 0xc000463900)
2019/10/10 12:40:16 DEBUG : POST /2/files/upload HTTP/1.1
Host: content.dropboxapi.com
User-Agent: rclone/v1.49.5
Transfer-Encoding: chunked
Authorization: XXXX
Content-Type: application/octet-stream
Dropbox-Api-Arg: {"path":"/tdir/Русский.txt","mode":{".tag":"overwrite"},"autorename":false,"client_modified":"2000-01-01T00:00:00Z","mute":false,"strict_conflict":false}
Accept-Encoding: gzip

0

And here is the response

2019/10/10 12:40:17 DEBUG : HTTP RESPONSE (req 0xc000463900)
2019/10/10 12:40:17 DEBUG : HTTP/1.1 200 OK
Transfer-Encoding: chunked
Cache-Control: no-cache
Connection: keep-alive
Content-Type: application/json
Date: Thu, 10 Oct 2019 11:40:17 GMT
Pragma: no-cache
Server: nginx
Vary: Accept-Encoding
X-Dropbox-Request-Id: 3a11434e22b08d87588de53cb34c047b
X-Robots-Tag: noindex, nofollow, noimageindex
X-Server-Response-Time: 553

257
{"name": "\u00d0\u00a0\u00d1\u0083\u00d1\u0081\u00d1\u0081\u00d0\u00ba\u00d0\u00b8\u00d0\u00b9.txt", "path_lower": "/tdir/\u00f0\u00a0\u00f1\u0083\u00f1\u0081\u00f1\u0081\u00f0\u00ba\u00f0\u00b8\u00f0\u00b9.txt", "path_display": "/tdir/\u00d0\u00a0\u00d1\u0083\u00d1\u0081\u00d1\u0081\u00d0\u00ba\u00d0\u00b8\u00d0\u00b9.txt", "id": "id:qqS0afUHwS0AAAAAAAPHng", "client_modified": "2000-01-01T00:00:00Z", "server_modified": "2019-10-10T11:40:17Z", "rev": "5948cdd90ee8c082af73a", "size": 0, "is_downloadable": true, "content_hash": "e3b0c44298fc1c149afbf4c8996fb92427ae41e4649b934ca495991b7852b855"}
0

Note that the name in the response appears to be corrupted.

If you decode this name you get

>>> print("\u00d0\u00a0\u00d1\u0083\u00d1\u0081\u00d1\u0081\u00d0\u00ba\u00d0\u00b8\u00d0\u00b9.txt")
Ð ÑÑÑÐºÐ¸Ð¹.txt

Which is now the name of the file in listings instead of "Русский.txt".

Since this capture is right at the HTTP level, I don't think it can be my code or the dropbox Go SDK, I think this must be a bug in the dropbox server code.

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Accepted answers

Greg-DB

Thanks for the report! Sending non-ASCII characters in HTTP headers is not officially supported, so please make sure you're encoding any non-ASCII characters in headers as documented here:

https://www.dropbox.com/developers/reference/json-encoding

There was a change on our server stack yesterday that affected how we handled HTTP headers without proper encoding. That resulted in malformed file paths/names like the user reported in the GitHub issue. We've reverted that change, so that should be working again, but please make sure your headers get encoded properly.

All comments

Здравко

Hi @ncw,

Take in account that http header content have to be ASCII-based and if need (as is in particular case) names (and not only) have to be JSON-encoded. JSON encoding is missing in your case.

Hope this helps.

Greg-DB

Thanks for the report! Sending non-ASCII characters in HTTP headers is not officially supported, so please make sure you're encoding any non-ASCII characters in headers as documented here:

https://www.dropbox.com/developers/reference/json-encoding

ncw

Thanks for that.

It must be a bug in dropbox Go SDK that the headers aren't being properly encoded

I'll report a bug there in a moment!

ncw

I made an issue in the Dropbox Go SDK repo which is where the problem needs to be fixed.

Hexrby

"We've reverted that change" - people with the Synology NAS are still having this problem.

Reported here: https://community.synology.com/enu/forum/1/post/129064

Greg-DB

@Hexrby Thanks for the information. If you're still seeing any broken functionality, please let the third party app developer know so that they can contact us with the relevant technical details so we can investigate.