Class: Clickwrap::Integrity::Attestor

Inherits:
Object
  • Object
show all
Defined in:
lib/clickwrap/integrity/attestor.rb

Overview

Invokes optional external adapters only after the required event commit. An outage can never roll back the protected action; every ordinary result is persisted, and an exception is reported through the host's existing after-commit failure hook.

Defined Under Namespace

Classes: ChainSnapshot

Instance Attribute Summary collapse

Class Method Summary collapse

Instance Method Summary collapse

Constructor Details

#initialize(event) ⇒ Attestor

Returns a new instance of Attestor.



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# File 'lib/clickwrap/integrity/attestor.rb', line 16

def initialize(event)
  @event = event
end

Instance Attribute Details

#event ⇒ Object (readonly)

Returns the value of attribute event.



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# File 'lib/clickwrap/integrity/attestor.rb', line 20

def event
  @event
end

Class Method Details

.attest_after_commit(event) ⇒ Object 



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# File 'lib/clickwrap/integrity/attestor.rb', line 14

def self.attest_after_commit(event) = new(event).attest_after_commit

Instance Method Details

#anchor_event ⇒ Object 



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# File 'lib/clickwrap/integrity/attestor.rb', line 65

def anchor_event
  adapter = Clickwrap.config.anchor_event_history_with
  attempted_at = Clickwrap.now
  snapshot = ChainSnapshot.new(
    chain_scope: event.chain_scope,
    sequence: event.chain_sequence,
    last_event_id: event.id,
    last_event_digest: event.event_digest
  )
  publication = normalized_result(adapter.anchor(snapshot))
  verification = if publication["anchored"] == true
                   # Verification receives the exact publication result
                   # as well as the expected chain head. An adapter that
                   # merely re-reads "some current head" cannot prove the
                   # reference stored beside this attestation is the one
                   # it actually checked.
                   normalized_result(adapter.verify(publication, snapshot))
                 else
                   { "checked" => false, "verified" => false,
                     "detail" => publication["detail"] }
                 end

  record!(
    kind: "event_anchor",
    state: attestation_state(publication["anchored"], verification),
    adapter: adapter,
    attempted_at: attempted_at,
    provider_result: publication,
    verification: verification,
    provider_reference: publication["reference"],
    provider_reported_at: parse_time(publication["published_at"]),
    chain_scope: event.chain_scope,
    chain_sequence: event.chain_sequence
  )
rescue StandardError => error
  record_exception(kind: "event_anchor", adapter: adapter,
                   attempted_at: attempted_at, error: error,
                   chain_scope: event.chain_scope, chain_sequence: event.chain_sequence)
end

#attest_after_commit ⇒ Object 



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# File 'lib/clickwrap/integrity/attestor.rb', line 22

def attest_after_commit
  timestamp_event if Clickwrap.config.timestamp_receipts_with
  anchor_event if Clickwrap.config.anchor_event_history_with && event.chain_scope.present?
end

#timestamp_event ⇒ Object 



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# File 'lib/clickwrap/integrity/attestor.rb', line 27

def timestamp_event
  adapter = Clickwrap.config.timestamp_receipts_with
  attempted_at = Clickwrap.now
  token = adapter.timestamp(event.event_digest)
  token_body = normalized_result(token)
  token_digest = token_body["digest"]

  unless token_digest.to_s == event.event_digest.to_s
    return record!(
      kind: "third_party_timestamp", state: "failed", adapter: adapter,
      attempted_at: attempted_at, provider_result: token_body,
      verification: { "checked" => false, "verified" => false,
                      "detail" => "The provider result named a different digest." }
    )
  end

  verification = if token_body["issued"] == true
                   normalized_result(adapter.verify(token_body["token"], event.event_digest))
                 else
                   { "checked" => false, "verified" => false,
                     "detail" => token_body["detail"] }
                 end

  record!(
    kind: "third_party_timestamp",
    state: attestation_state(token_body["issued"], verification),
    adapter: adapter,
    attempted_at: attempted_at,
    provider_result: token_body,
    verification: verification,
    provider_reference: token_body["token_reference"],
    provider_reported_at: parse_time(token_body["provider_reported_time"])
  )
rescue StandardError => error
  record_exception(kind: "third_party_timestamp", adapter: adapter,
                   attempted_at: attempted_at, error: error)
end