class

M3U8::SessionKeyItem

Inherits M3U8::Encryptable / M3U8::Concern / Reference / Object

SessionKeyItem represents a set of attributes for the EXT-X-SESSION-KEY tag, which is used in HTTP Live Streaming (HLS) to specify encryption keys that apply to a session of Media Segments.

According to RFC 8216, Section 4.3.4.5, the EXT-X-SESSION-KEY tag provides information such as the encryption METHOD, the URI to obtain the key, the Initialization Vector IV, and optionally the KEYFORMAT and KEYFORMATVERSIONS.

Example of an EXT-X-SESSION-KEY tag:

#EXT-X-SESSION-KEY:METHOD=AES-128,URI="http://test.key",IV=D512BBF,KEYFORMAT="identity",KEYFORMATVERSIONS="1/3"

All attributes defined for the EXT-X-KEY tag (RFC 8216, Section 4.3.2.4) are also defined for the EXT-X-SESSION-KEY, except that the value of the METHOD attribute MUST NOT be NONE.

This class leverages the Encryptable module to parse and format these attributes.

Class methods

parse(text)

Parses a text string representing an EXT-X-SESSION-KEY tag and returns a new SessionKeyItem instance.

It extracts the attribute list from the tag line using parse_attributes (from the M3U8::Concern module), then converts the extracted values using Encryptable.convert_key.

Example:

text = %(#EXT-X-SESSION-KEY:METHOD=AES-128,URI="http://test.key",IV=D512BBF,KEYFORMAT="identity",KEYFORMATVERSIONS="1/3")
SessionKeyItem.parse(text)
# => #<M3U8::SessionKeyItem:0x7e4a9ab264c0
#     @iv="D512BBF",
#     @key_format="identity",
#     @key_format_versions="1/3",
#     @method="AES-128",
#     @uri="http://test.key">

Source

Instance methods

to_s

Returns the string representation of the EXT-X-SESSION-KEY tag.

The output is generated by concatenating the formatted encryption key attributes (provided by the Encryptable module) with the tag identifier.

Example:

options = {
  method:              "AES-128",
  uri:                 "http://test.key",
  iv:                  "D512BBF",
  key_format:          "identity",
  key_format_versions: "1/3",
}
SessionKeyItem.new(options).to_s
# => "#EXT-X-SESSION-KEY:METHOD=AES-128,URI=\"http://test.key\",IV=D512BBF,KEYFORMAT=\"identity\",KEYFORMATVERSIONS=\"1/3\""

Source