App updates broken when running NextCloud on OpenWrt

[flyn-org]

I run NextCloud 19.0.4 on OpenWrt. OpenWrt's libcurl does not have support for compression, and I suspect this is getting in the way of NextCloud updating its apps. Here are the libraries OpenWrt's libcurl depends on:

# ldd /usr/lib/libcurl.so.4
	ldd (0x7fdb98182000)
	libwolfssl.so.24 => /usr/lib/libwolfssl.so.24 (0x7fdb97fd0000)
	libgcc_s.so.1 => /lib/libgcc_s.so.1 (0x7fdb97fbc000)
	libc.so => ldd (0x7fdb98182000)

Loading https://www.flyn.org/share/index.php/settings/apps does not present me with an option to update out-of-date apps. Rather, I see this in the logs:

{"reqId":"[ID]","level":2,"time":"2020-11-14T17:12:03+00:00","remoteAddr":"[IP]","user":"[USER]","app":"appstoreFetcher","method":"GET","url":"/share/index.php/settings/apps/list","message":{"Exception":"GuzzleHttp\\Exception\\RequestException","Message":"cURL error 61: Unrecognized content encoding type. libcurl understands identity content encodings. (see https://curl.haxx.se/libcurl/c/libcurl-errors.html)", ... "args":["get","https://apps.nextcloud.com/api/v1/apps.json" ...

[flyn-org]

I confirmed that compiling libcurl on OpenWrt with libz support works around this bug. Is the HTTP compression scheme negotiation in NextCloud, Guzzle, or the app server broken?

[LorbusChris]

It looks like this is the culprit: https://github.com/nextcloud/server/blob/master/lib/private/Http/Client/Client.php#L95 - the only understood encoding type is identity for curl on OpenWrt, but the linked line will make it so that it requests gzip-encoded responses anyway.

Maybe there's a way to override this default accept-encoded header setting, changing it from gzip to identity.

An even better solution would be to build curl on openwrt with support for compression...

[LorbusChris]

I can confirm that changing it from gzip to identity fixed the issue..

xref: https://gitlab.nic.cz/turris/turris-os-packages/-/issues/662

[LorbusChris]

Hi @MorrisJobke, I'm tagging you since you made the change: https://github.com/nextcloud/server/blame/86678ba5df7b74fab9ac739ca17109cd717f8062/lib/private/Http/Client/Client.php#L95 .

tl;dr on OpenWRT curl doesn't support compression, and thus what we need here is a way to configure an override for that hardcoded gzip default Accept-Encoding header, replacing it with identity.

[MorrisJobke]

@LorbusChris @flyn-org Thanks for the report and the deep dive into the issue. Unfortunately I need to say that adding more config options also adds to the complexity of Nextcloud.

Also running Nextcloud on OpenWRT seems to be a pretty rare setup. Thus I would recommend you to just patch out the line in your installation.

Sorry for the inconvenience here, but we have to also use our limited resources that they are useful for as many people as possible.