[Haskell-cafe] Decompressing and http-enumerator

[Michael Snoyman]

On Mon, Aug 29, 2011 at 5:28 PM, Herbert Valerio Riedel <hvr at gnu.org> wrote:
> On Mon, 2011-08-29 at 13:21 +0200, Gregory Collins wrote:
>> A web server should not be setting "Content-encoding: gzip" on a
>> .tar.gz file.
>
> Why not? From RFC2616 compliant servers I'd expect a .tar.gz file to
> have the Content-* headers provide meta-information about the
> content[1], e.g.
>
>  Content-Type: application/x-tar
>  Content-Encoding: gzip
>  Transfer-Encoding: chunked
>
>
> If I want to detach the gzip encoding from the "content" (or "entity"),
> I'd move it to the Transfer-Encoding header[2], e.g.:
>
>  Content-Type: application/x-tar
>  Transfer-Encoding: gzip, chunked
>
>
>
>
>
> [1]: See RFC2616 sec7.2.1: "Content-Type specifies the media type of the
> underlying data. Content-Encoding may be used to indicate any additional
> content codings applied to the data, usually for the purpose of data
> compression, that are a property of the requested resource."
>
> [2]: See RFC2616 sec4.3: "Transfer-Encoding is a property of the
> message, not of the entity, and thus MAY be added or removed by any
> application along the request/response chain."
>
>
>
>

"chunked" is the only valid transfer-encoding[1], while gzip must be
specified on the content-encoding header[2]. For a simple example of
these two, look at the response headers from Haskellers[3] in
something like Chrome developer tools.

[1] http://www.w3.org/Protocols/rfc2616/rfc2616-sec3.html#sec3.6
[2] http://www.w3.org/Protocols/rfc2616/rfc2616-sec3.html#sec3.5
[3] http://www.haskellers.com/