86 lines
2.2 KiB
Ruby
86 lines
2.2 KiB
Ruby
require "digest"
|
|
|
|
module Pigeon
|
|
class Message
|
|
attr_reader :author, :kind, :body, :signature, :depth, :prev
|
|
|
|
class VerificationError < StandardError; end
|
|
|
|
VERFIY_ERROR = "Expected field `%s` to equal %s, got: %s"
|
|
|
|
# Store a message that someone (not the LocalIdentity)
|
|
# has authored.
|
|
def self.ingest(author:, body:, depth:, kind:, prev:, signature:)
|
|
params = { author: RemoteIdentity.new(author),
|
|
kind: kind,
|
|
body: body,
|
|
prev: prev,
|
|
signature: signature,
|
|
depth: depth }
|
|
# Kind of weird to use `send` but #save! is private,
|
|
# and I don't want people calling it directly without going through the
|
|
# lexer / parser first.
|
|
new(**params).send(:save!)
|
|
end
|
|
|
|
def render
|
|
template.render.chomp
|
|
end
|
|
|
|
def multihash
|
|
tpl = self.render
|
|
digest = Digest::SHA256.digest(tpl)
|
|
sha256 = Helpers.b32_encode(digest)
|
|
"#{MESSAGE_SIGIL}#{sha256}#{BLOB_FOOTER}"
|
|
end
|
|
|
|
private
|
|
|
|
def save!
|
|
return store.read_message(multihash) if store.message?(multihash)
|
|
verify_depth_prev_and_depth
|
|
verify_signature
|
|
self.freeze
|
|
store.save_message(self)
|
|
self
|
|
end
|
|
|
|
def assert(field, actual, expected)
|
|
unless actual == expected
|
|
message = VERFIY_ERROR % [field, actual || "nil", expected || "nil"]
|
|
raise VerificationError, message
|
|
end
|
|
end
|
|
|
|
def verify_depth_prev_and_depth
|
|
count = store.get_message_count_for(author.multihash)
|
|
expected_prev = store.get_message_by_depth(author.multihash, count - 1) || Pigeon::EMPTY_MESSAGE
|
|
assert("depth", count, depth)
|
|
assert("prev", prev, expected_prev)
|
|
end
|
|
|
|
def verify_signature
|
|
tpl = template.render_without_signature
|
|
Helpers.verify_string(author, signature, tpl)
|
|
end
|
|
|
|
def initialize(author:, kind:, body:, depth:, prev:, signature: nil)
|
|
raise MISSING_BODY if body.empty?
|
|
@author = author
|
|
@body = body
|
|
@depth = depth
|
|
@kind = kind
|
|
@prev = prev || Pigeon::EMPTY_MESSAGE
|
|
@signature = signature
|
|
end
|
|
|
|
def template
|
|
MessageSerializer.new(self)
|
|
end
|
|
|
|
def store
|
|
Pigeon::Storage.current
|
|
end
|
|
end
|
|
end
|