Always send a language header in all requests

[michaelstingl]

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Feature description

Latest oCIS notifications API (/ocs/v2.php/apps/notifications/api/v1/notifications?format=json) responds with translated content. Other endpoints will learn this too.

Proposed solution

Desktop app should always send a language header in all requests which follows the Accept-Language spec:

• https://developer.mozilla.org/en-US/docs/Web/HTTP/Headers/Accept-Language

Alternative solutions you considered

No response

Additional context

Related:

• Web: [web] Always send a language header in all requests web#8612
• iOS: [FEATURE REQUEST] Always send a language header in all requests ios-app#1193
• Android: [FEATURE REQUEST] Always send a language header in all requests android#3980

[TheOneRing]

I would only enable that on a per endpoint basis, I don't know where we parse random strings and thus "only speak English"

[michaelstingl]

I would only enable that on a per endpoint basis, I don't know where we parse random strings and thus "only speak English"

Better send same to all endpoints.

[fmoc]

Note: @TheOneRing thinks there might be at least one location where we actually parse an error message from the server (somewhere in the common error handling). We may need to either replace this with a more reliable solution (if possible) or force an English locale in Accept-Language for these requests explicitly.

[TheOneRing]

client/src/libsync/owncloudpropagator_p.h

Lines 78 to 87 in e4ae053

	case 503: {
	// When the server is in maintenance mode, we want to exit the sync immediatly
	// so that we do not flood the server with many requests
	// BUG: This relies on a translated string and is thus unreliable.
	// In the future it should return a NormalError and trigger a status.php
	// check that detects maintenance mode reliably and will terminate the sync run.
	auto probablyMaintenance =
	errorBody.contains(R"(>Sabre\DAV\Exception\ServiceUnavailable<)")
	&& !errorBody.contains("Storage is temporarily not available");
	return probablyMaintenance ? SyncFileItem::FatalError : SyncFileItem::NormalError;

[HanaGemela]

Passed ownCloud 5.0.0.11523-alpha.1