Overhaul event content representation

event/encryption.go

@@ -0,0 +1,108 @@
+// Copyright (c) 2020 Tulir Asokan
+//
+// This Source Code Form is subject to the terms of the Mozilla Public
+// License, v. 2.0. If a copy of the MPL was not distributed with this
+// file, You can obtain one at http://mozilla.org/MPL/2.0/.
+
+package event
+
+import (
+	"encoding/base64"
+	"errors"
+
+	"maunium.net/go/mautrix/id"
+)
+
+// Algorithm is a Matrix message encryption algorithm.
+// https://matrix.org/docs/spec/client_server/r0.6.0#messaging-algorithm-names
+type Algorithm string
+
+const (
+	AlgorithmOlmV1    Algorithm = "m.olm.v1.curve25519-aes-sha2"
+	AlgorithmMegolmV1 Algorithm = "m.megolm.v1.aes-sha2"
+)
+
+var unpaddedBase64 = base64.StdEncoding.WithPadding(base64.NoPadding)
+
+// UnpaddedBase64 is a byte array that implements the JSON Marshaler and Unmarshaler interfaces
+// to encode and decode the byte array as unpadded base64.
+type UnpaddedBase64 []byte
+
+func (ub64 *UnpaddedBase64) UnmarshalJSON(data []byte) error {
+	if data[0] != '"' || data[len(data)-1] != '"' {
+		return errors.New("failed to decode data into bytes: input doesn't look like a JSON string")
+	}
+	*ub64 = make([]byte, unpaddedBase64.DecodedLen(len(data)-2))
+	_, err := unpaddedBase64.Decode(*ub64, data[1:len(data)-1])
+	return err
+}
+
+func (ub64 *UnpaddedBase64) MarshalJSON() ([]byte, error) {
+	data := make([]byte, unpaddedBase64.EncodedLen(len(*ub64))+2)
+	data[0] = '"'
+	data[len(data)-1] = '"'
+	unpaddedBase64.Encode(data[1:len(data)-1], *ub64)
+	return data, nil
+}
+
+// EncryptionEventContent represents the content of a m.room.encryption state event.
+// https://matrix.org/docs/spec/client_server/r0.6.0#m-room-encryption
+type EncryptionEventContent struct {
+	// The encryption algorithm to be used to encrypt messages sent in this room. Must be 'm.megolm.v1.aes-sha2'.
+	Algorithm Algorithm `json:"algorithm"`
+	// How long the session should be used before changing it. 604800000 (a week) is the recommended default.
+	RotationPeriodMillis int64 `json:"rotation_period_ms,omitempty"`
+	// How many messages should be sent before changing the session. 100 is the recommended default.
+	RotationPeriodMessages int `json:"rotation_period_messages,omitempty"`
+}
+
+// EncryptedEventContent represents the content of a m.room.encrypted message event.
+// This struct only supports the m.megolm.v1.aes-sha2 algorithm. The legacy m.olm.v1 algorithm is not supported.
+// https://matrix.org/docs/spec/client_server/r0.6.0#m-room-encrypted
+type EncryptedEventContent struct {
+	Algorithm  Algorithm      `json:"algorithm"`
+	SenderKey  string         `json:"sender_key"`
+	DeviceID   id.DeviceID    `json:"device_id"`
+	SessionID  string         `json:"session_id"`
+	Ciphertext UnpaddedBase64 `json:"ciphertext"`
+}
+
+// RoomKeyEventContent represents the content of a m.room_key to_device event.
+// https://matrix.org/docs/spec/client_server/r0.6.0#m-room-key
+type RoomKeyEventContent struct {
+	Algorithm  Algorithm `json:"algorithm"`
+	RoomID     id.RoomID `json:"room_id"`
+	SessionID  string    `json:"session_id"`
+	SessionKey string    `json:"session_key"`
+}
+
+// ForwardedRoomKeyEventContent represents the content of a m.forwarded_room_key to_device event.
+// https://matrix.org/docs/spec/client_server/r0.6.0#m-forwarded-room-key
+type ForwardedRoomKeyEventContent struct {
+	RoomKeyEventContent
+	SenderClaimedKey   string   `json:"sender_claimed_ed25519_key"`
+	ForwardingKeyChain []string `json:"forwarding_curve25519_key_chain"`
+}
+
+type KeyRequestAction string
+
+const (
+	KeyRequestActionRequest = "request"
+	KeyRequestActionCancel  = "request_cancellation"
+)
+
+// RoomKeyRequestEventContent represents the content of a m.room_key_request to_device event.
+// https://matrix.org/docs/spec/client_server/r0.6.0#m-room-key-request
+type RoomKeyRequestEventContent struct {
+	Body               RequestedKeyInfo `json:"body"`
+	Action             KeyRequestAction `json:"action"`
+	RequestingDeviceID id.DeviceID      `json:"requesting_device_id"`
+	RequestID          string           `json:"request_id"`
+}
+
+type RequestedKeyInfo struct {
+	Algorithm Algorithm `json:"algorithm"`
+	RoomID    id.RoomID `json:"room_id"`
+	SenderKey string    `json:"sender_key"`
+	SessionID string    `json:"session_id"`
+}