Hieu Nguyen

TIL - HTTP headers: Content negotiation

Aug 1 2018

HTTP client and server can negotiate content type that is transported using header fields Accept, Accept-Encoding, Accept-Language, …

One of the usage of these fields is to compress the content to make it smaller, thus faster to transport via the internet. There are several compress algorithms, such as gzip and deflate. Some algorithms are supported in most servers/clients, some are not (Android does not support deflate algorith).

In Ruby, some HTTP clients, such as RestClient, automatically add these headers to speed up the request/response time. Some clients, such as httprb, supports these headers, but requires manual handling:

# :auto_inflate is for automatically decompressing data
# `Accept-Encoding` header is used for signalling compressing in server
HTTP.use(:auto_inflate).headers('Accept-Encoding' => 'gzip, deflate').get(url)

You can compare the content-length header in the response with the below command:

# This usually have bigger content-length than the above command