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module Athena::Negotiation #

The Athena::Negotiation component allows an application to support content negotiation. The component has no dependencies and is framework agnostic; supporting various negotiators.

Getting Started#

If using this component within the Athena Framework, it is already installed and required for you. Checkout the manual for some additional information on how to use it within the framework.

If using it outside of the framework, you will first need to add it as a dependency:

    github: athena-framework/negotiation
    version: ~> 0.1.0

Then run shards install, being sure to require it via require "athena-negotiation".


The main type of Athena::Negotiation is ANG::AbstractNegotiator which is used to implement negotiators for each Accept* header. Athena::Negotiation exposes class level getters for each negotiator; that return a lazily initialized singleton instance. Each negotiator exposes two methods: ANG::AbstractNegotiator#best and ANG::AbstractNegotiator#ordered_elements.

Media Type#

negotiator = ANG.negotiator

accept_header = "text/html, application/xhtml+xml, application/xml;q=0.9"
priorities = ["text/html; charset=UTF-8", "application/json", "application/xml;q=0.5"]

accept =, priorities).not_nil!

accept.media_range # => "text/html"
accept.parameters  # => {"charset" => "UTF-8"}

The ANG::Negotiator type returns an ANG::Accept, or nil if negotiating the best media type has failed.

Character Set#

negotiator = ANG.charset_negotiator

accept_header = "ISO-8859-1, UTF-8; q=0.9"
priorities = ["iso-8859-1;q=0.3", "utf-8;q=0.9", "utf-16;q=1.0"]

accept =, priorities).not_nil!

accept.charset # => "utf-8"
accept.quality # => 0.9

The ANG::CharsetNegotiator type returns an ANG::AcceptCharset, or nil if negotiating the best character set has failed.


negotiator = ANG.encoding_negotiator

accept_header = "gzip;q=1.0, identity; q=0.5, *;q=0"
priorities = ["gzip", "foo"]

accept =, priorities).not_nil!

accept.coding # => "gzip"

The ANG::EncodingNegotiator type returns an ANG::AcceptEncoding, or nil if negotiating the best encoding has failed.


negotiator = ANG.language_negotiator

accept_header = "en; q=0.1, fr; q=0.4, zh-Hans-CN; q=0.9, de; q=0.2"
priorities = ["de", "zh-Hans-CN", "en"]

accept =, priorities).not_nil!

accept.language # => "zh"
accept.region   # => "cn"
accept.script   # => "hans"

The ANG::LanguageNegotiator type returns an ANG::AcceptLanguage, or nil if negotiating the best language has failed.


VERSION = "0.1.4"#

Class methods#


Returns a lazily initialized ANG::CharsetNegotiator singleton instance.

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Returns a lazily initialized ANG::EncodingNegotiator singleton instance.

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Returns a lazily initialized ANG::LanguageNegotiator singleton instance.

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Returns a lazily initialized ANG::Negotiator singleton instance.

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