Adding header: 'Accept-Language"

[AdaWMPL]

I must add header: "Accept-Language: en" while I'm adding a column by fetching URLs. Normally, my GREL code looks like this: "https://api-zbiory.mnk.pl/api/object/"+value, but to get data in English I must add this header...
I know that I can use Python instead of GREL to create a request with this header, but it isn't simple and create some problems with code, many errors and stress.

Proposed solution

Add header "Accept-Language" to the list of available headings in window: "Add column by fetching URLs based on column ..."

Alternatives considered

Additional context

[ostephens]

The simple solution is to add this http header to the existing list at

OpenRefine/main/src/com/google/refine/commands/HttpHeadersSupport.java

Lines 65 to 69 in 5c7f66b

	static {
	registerHttpHeader("User-Agent", RefineServlet.FULLNAME);
	registerHttpHeader("Accept", "*/*");
	registerHttpHeader("Authorization", "");
	}

However, it would be nicer to enable user-defined headers instead of the current static list so users can add headers as required. I'm not sure of the best approach but wonder if it might make sense to have a setting for supported headers that the user can add to? The way it's currently designed means that extensions can register additional headers as needed which was a deliberate design choice and I think would be good to maintain that option

[tfmorris]

Since adding the rest of the Accept-* headers is easy, why don't we start with that?