Bugfix/bulk upload empty files

[mgallien]

Summary

Solve long running issue with bulk upload of empty files.
Require also fixes from desktop client see nextcloud/desktop#5871

TODO

• ...

Checklist

• Code is properly formatted
• Sign-off message is added to all commits
• Tests (unit, integration, api and/or acceptance) are included
• Screenshots before/after for front-end changes
• Documentation (manuals or wiki) has been updated or is not required
• Backports requested where applicable (ex: critical bugfixes)
  should probably be backported to all maintained releases with bulk upload

[kesselb]

Thanks for your patch 👍

The change for the desktop client is important.

I could reproduce the issue with my development setup (nginx proxy -> php container),
but the requests for /remote.php/dav/bulk did not trigger my breakpoint.

proxy_1      | nginx.1     | 2023/07/08 20:33:56 [info] 46#46: *34 client prematurely closed connection, client: 172.19.0.1, server: server.internal, request: "POST /remote.php/dav/bulk HTTP/1.1", host: "server.internal"
proxy_1      | nginx.1     | server.internal 172.19.0.1 - admin [08/Jul/2023:20:33:56 +0000] "POST /remote.php/dav/bulk HTTP/1.1" 400 0 "-" "Mozilla/5.0 (Linux) mirall/3.9.50 (build 16487) (Nextcloud, ubuntu-6.2.0-24-generic ClientArchitecture: x86_64 OsArchitecture: x86_64)" "-"

It seems to me that nginx did not forward the post request without a body to the php container.
Using the build from your pr made it work.

I did some testing with the patched desktop client and the server pr.

1. Open a terminal
2. Change directory to your Nextcloud sync folder
3. Run echo "123" > test61.txt; touch test62.txt; echo "456" > test63.txt

Result:

cat test61.txt 
123

cat test62.txt 
--boundary_.oOo._EfhWH90em6640g8imIdDSkdgh4fStM3o
Content-Length: 4
Content-Type: application/octet-stream
X-File-MD5: d2d362cdc6579390f1c0617d74a7913d
X-File-Mtime: 1688851265
X-File-Path: /test63.txt

456

--boundary_.oOo._EfhWH90em6640g8imIdDSkdgh4fStM3o--

Notification: test63.txt could not be synced due to an error.
And a put request for test63.txt writing the proper content.

I guess stream_get_line with $length = 0 is the problem here,
because the default socket chunk size is used then.

Index: apps/dav/lib/BulkUpload/MultipartRequestParser.php
IDEA additional info:
Subsystem: com.intellij.openapi.diff.impl.patch.CharsetEP
<+>UTF-8
===================================================================
diff --git a/apps/dav/lib/BulkUpload/MultipartRequestParser.php b/apps/dav/lib/BulkUpload/MultipartRequestParser.php
--- a/apps/dav/lib/BulkUpload/MultipartRequestParser.php	(revision 9bf69115593a9abaedd8cc8d886725253100f3c0)
+++ b/apps/dav/lib/BulkUpload/MultipartRequestParser.php	(date 1688852480282)
@@ -211,7 +211,11 @@
 			throw new BadRequest("Computed md5 hash is incorrect.");
 		}
 
-		$content = stream_get_line($this->stream, $length);
+		if ($length === 0) {
+			$content = '';
+		} else {
+			$content = stream_get_line($this->stream, $length);
+		}
 
 		if ($content === false) {
 			throw new Exception("Fail to read part's content.");

Made it work for me.

Please keep my setup with the reverse proxy in mind. We should probably test the patch without a reverse proxy.
And I don't know if the logic is backwards compatible.

[mgallien]

@kesselb
I am testing with the docker based setup from Julius that uses a proxy
Tested with your shell snippet and pushed your suggested changes. Everything is working fine now.

[mgallien]

/backport to stable24

[mgallien]

/backport to stable25

[mgallien]

/backport to stable26

[mgallien]

/backport to stable27

[backportbot-nextcloud]

The backport to stable27 failed. Please do this backport manually.

# Switch to the target branch and update it
git checkout stable27
git pull origin stable27

# Create the new backport branch
git checkout -b fix/foo-stable27

# Cherry pick the change from the commit sha1 of the change against the default branch
# This might cause conflicts. Resolve them.
git cherry-pick abc123

# Push the cherry pick commit to the remote repository and open a pull request
git push origin fix/foo-stable27

More info at https://docs.nextcloud.com/server/latest/developer_manual/getting_started/development_process.html#manual-backport

[mgallien]

/backport to stable27

[mgallien]

/backport to stable23

[kesselb]

Please don't forget to review the pr for 24 and check if we also need it: #39508