un-gzip based on content-encoding

[matthusby]

If the response has Content-Encoding: gzip the body should be automatically unzipped.

[edgurgel]

This will be done upstream by hackney: benoitc/hackney#155

We can keep this issue open until it's available.

[marvelm]

For anyone looking for a stopgap until this feature is implemented:

res = HTTPoison.get(url)
gzipped = Enum.any?(res.headers, fn (kv) ->
  case kv do
    {"Content-Encoding", "gzip"} -> true
    {"Content-Encoding", "x-gzip"} -> true
    _ -> false
  end
end)

# body is an Elixir string
body = if gzipped do
    :zlib.gunzip(res.body)
  else
    res.body
  end

[jaimeiniesta]

@marvelm works like a charm thanks - but some servers return { "Content-Encoding", "x-gzip" } instead.

[setharnold]

If someone gets around to implementing this, it might also be worth implementing support for brotli as well; it's supported in both Firefox and Chromium so is likely to be supported by more servers over time.

Thanks