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chore: Basic backend y.js message decoder
Signed-off-by: Julius Härtl <jus@bitgrid.net>
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| Original file line number | Diff line number | Diff line change |
|---|---|---|
| @@ -0,0 +1,88 @@ | ||
| <?php | ||
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| namespace OCA\Text; | ||
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| use InvalidArgumentException; | ||
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| /** | ||
| * Steps are base64 encoded messages of the yjs protocols | ||
| * https://github.com/yjs/y-protocols | ||
| * | ||
| * This class is a simple representation of a message containing some methods | ||
| * to decode parts of it for what we need on the backend | ||
| * | ||
| * Relevant resources: | ||
| * https://github.com/yjs/y-protocols/blob/master/PROTOCOL.md | ||
| * https://github.com/yjs/y-websocket/blob/master/src/y-websocket.js#L19-L22 | ||
| * https://github.com/yjs/y-protocols/blob/master/sync.js#L38-L40 | ||
| * https://github.com/dmonad/lib0/blob/master/decoding.js | ||
| */ | ||
| class YjsMessage { | ||
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| public const YJS_MESSAGE_SYNC = 0; | ||
| public const YJS_MESSAGE_AWARENESS = 1; | ||
| public const YJS_MESSAGE_AWARENESS_QUERY = 3; | ||
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| public const YJS_MESSAGE_SYNC_STEP1 = 0; | ||
| public const YJS_MESSAGE_SYNC_STEP2 = 1; | ||
| public const YJS_MESSAGE_SYNC_UPDATE = 2; | ||
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| private int $pos = 0; | ||
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| public function __construct( | ||
| private string $data = '' | ||
| ) { | ||
| } | ||
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| public static function fromBase64(string $data = ''): self { | ||
| return new self(base64_decode($data)); | ||
| } | ||
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| /** | ||
| * https://github.com/dmonad/lib0/blob/bd69ab4dc701d77e808f2bab08d96d63acd297da/decoding.js#L242 | ||
| */ | ||
| public function readVarUint(): int { | ||
| $bytes = unpack('C*', substr($this->data, $this->pos, 4)); | ||
| $segments = []; | ||
| $offset = 0; | ||
| foreach ($bytes as $byte) { | ||
| $offset++; | ||
| $segments[] = (0x7f & $byte); | ||
|
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| if (($byte & 0x80) === 0) { | ||
| $integer = 0; | ||
| foreach($segments as $segment) { | ||
| $integer <<= 7; | ||
| $integer |= (0x7f & $segment); | ||
| } | ||
| $this->pos += $offset; | ||
| return $integer; | ||
| } | ||
| } | ||
| if (($byte & 0x80) !== 0) { | ||
| throw new InvalidArgumentException('Incomplete byte sequence.'); | ||
| } | ||
| throw new InvalidArgumentException('Incomplete byte sequence.'); | ||
| } | ||
|
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| public function getYjsMessageType(): int { | ||
| $oldPos = $this->pos; | ||
| $this->pos = 0; | ||
| $messageType = $this->readVarUint(); | ||
| $this->pos = $oldPos; | ||
| return $messageType; | ||
| } | ||
|
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| public function getYjsSyncType(): int { | ||
| $oldPos = $this->pos; | ||
| $this->pos = 0; | ||
| $messageType = $this->readVarUint(); | ||
| if ($messageType !== self::YJS_MESSAGE_SYNC) { | ||
| throw new \ValueError('Message is not a sync message'); | ||
| } | ||
| $syncType = $this->readVarUint(); | ||
| $this->pos = $oldPos; | ||
| return $syncType; | ||
| } | ||
|
|
||
| } |
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| Original file line number | Diff line number | Diff line change |
|---|---|---|
| @@ -0,0 +1,42 @@ | ||
| <?php | ||
|
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| namespace OCA\Text; | ||
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| use Test\TestCase; | ||
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| class YjsMessageTest extends TestCase { | ||
| protected function setUp(): void { | ||
| parent::setUp(); | ||
| } | ||
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| // https://github.com/yjs/y-dat/blob/745d25f9690fceae5901d1225575fe8b6bcafdd7/src/y-dat.js#LL207C59-L210C1 | ||
| public function dataMessageTypes() { | ||
| return [ | ||
| // | ||
| ['AAABAA==', 0, 0], | ||
| // messageSync messageYjsSyncStep1 | ||
| ['AAAyCIqghaQNBvrS2LoMB8L10I8KrQPD+t3RB2DcrYL4A40Ema2O4AMHz9bk8AIOtbm0PAE=', 0, 0], | ||
| // messageAwareness | ||
| ['AQoBkZWK7gMAAnt9', 1, null], | ||
| ['AUIBwvXQjwqWAzl7InVzZXIiOnsibmFtZSI6ImFkbWluIiwiY29sb3IiOiIjZDA5ZTZkIn0sImN1cnNvciI6bnVsbH0=', 1, null], | ||
| ['AegBAcP63dEHtwHeAXsidXNlciI6eyJuYW1lIjoiR3Vlc3QiLCJjb2xvciI6IiM5M2IyN2IifSwiY3Vyc29yIjp7ImFuY2hvciI6eyJ0eXBlIjp7ImNsaWVudCI6MjcxNzEzNzYwMiwiY2xvY2siOjl9LCJ0bmFtZSI6bnVsbCwiaXRlbSI6bnVsbCwiYXNzb2MiOjB9LCJoZWFkIjp7InR5cGUiOnsiY2xpZW50IjoyNzE3MTM3NjAyLCJjbG9jayI6OX0sInRuYW1lIjpudWxsLCJpdGVtIjpudWxsLCJhc3NvYyI6MH19fQ==', 1, null], | ||
| ['AbsBAZGViu4DArIBeyJ1c2VyIjp7Im5hbWUiOiJHdWVzdCIsImNvbG9yIjoiI2I4YmU2OCJ9LCJjdXJzb3IiOnsiYW5jaG9yIjp7InR5cGUiOm51bGwsInRuYW1lIjoiZGVmYXVsdCIsIml0ZW0iOm51bGwsImFzc29jIjowfSwiaGVhZCI6eyJ0eXBlIjpudWxsLCJ0bmFtZSI6ImRlZmF1bHQiLCJpdGVtIjpudWxsLCJhc3NvYyI6MH19fQ==', 1, null], | ||
| // messageSync messageYjsUpdate | ||
| ['AAISAQHD+t3RB2CEwvXQjwpHAWEA', 0, 2], | ||
| ['AAI0AQOKoIWkDQAHAQdkZWZhdWx0AwlwYXJhZ3JhcGgHAIqghaQNAAYEAIqghaQNAQR0ZXN0AA==', 0, 2], | ||
| ['AAIdAQGRlYruAx2okZWK7gMbAXcCaC0BkZWK7gMBGwE=', 0, 2], | ||
| ['AAIKAAGRlYruAwEVBA==', 0, 2], | ||
| ]; | ||
| } | ||
|
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| /** @dataProvider dataMessageTypes */ | ||
| public function testMessageTypes($data, $type, $subtype) { | ||
| $buffer = YjsMessage::fromBase64($data); | ||
| $unpack1 = $buffer->getYjsMessageType(); | ||
| self::assertEquals($type, $unpack1, 'type'); | ||
| if ($subtype !== null) { | ||
| $unpack2 = $buffer->getYjsSyncType(); | ||
| self::assertEquals($subtype, $unpack2); | ||
| } | ||
| } | ||
| } |