`class ETag`

The etag header represents the entity tag for a resource.

The etag header provides a unique identifier for a specific version of a resource, typically used for cache validation or conditional requests. It can be either a strong or weak validator as defined in RFC 9110.

Definitions

`def self.parse(value)`

Parses a raw header value.

Signature

parameter　value　String: a raw header value.
returns　ETag: a new instance.

Implementation

def self.parse(value)
	self.new(value)
end

`def self.coerce(value)`

Coerces a value into a parsed header object.

Signature

parameter　value　String: the value to coerce.
returns　ETag: a parsed header object.

Implementation

def self.coerce(value)
	self.new(value.to_s)
end

`def <<(value)`

Replaces the current value of the etag header.

Signature

parameter　value　String: a raw header value for the etag header.

Implementation

def << value
	replace(value)
end

`def weak?`

Checks whether the etag is a weak validator.

Weak validators indicate semantically equivalent content but may not be byte-for-byte identical.

Signature

returns　Boolean: whether the etag is weak.

Implementation

def weak?
	self.start_with?("W/")
end

`def self.trailer?`

Whether this header is acceptable in HTTP trailers. ETag headers can safely appear in trailers as they provide cache validation metadata.

Signature

returns　Boolean: true, as ETag headers are metadata that can be computed after response generation.

Implementation

def self.trailer?
	true
end