Disentangle Content-Encoding, Transfer-Encoding, character set conversion and chunked transfers. about webzmachine

[mworrell]

/cc @mmzeeman @arjan @kaos

[mmzeeman]

Nice one :-) Some parts of webmachine desperately need a cleanup. This will make things more clear in this area.

Side note: There is a separate header for negotiating which transfer encoding to use. This is the TE header. Browsers generally don't send this header. This means that in the normal case identity and chunked are allowed, not gzip. Even if that is specified in the Accept-Encoding header. The Accept-Encoding header is restricted to specifying content encoding only. Proxies may add an TE header of course, but I don't think that is done in practice.

[kaos]

👍

[mworrell]

The selected content-encoding/charset can be fetched with:

wrq:resp_content_encoding(ReqData).
wrq:resp_chosen_charset(ReqData).

There are some more new wrq functions:

resp_transfer_encoding/1, set_resp_transfer_encoding/2,
resp_content_encoding/1, set_resp_content_encoding/2,
resp_content_type/1, set_resp_content_type/2,
resp_chosen_charset/1, set_resp_chosen_charset/2,

See wrq.erl for more details.

Also added support for file:sendfile, and some new content return values, complete list is now:

iolist()
{device, IO}
{device, Length, IO}
{file, Filename}
{file Length, Filename}
{stream, StreamFun}
{stream, Size, StreamFun}
{writer, WriterFun}

[mmzeeman]

That looks nice. I will place the same controller workflow inside the new elli + machine solution.