319 lines
13 KiB
JavaScript
319 lines
13 KiB
JavaScript
import { Client } from "../client.js";
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import { readJsonObject, writeJsonObject, readProtobufMessage, writeProtobufMessage, } from "../encoding/index.js";
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import { ClientError, ProtoError, ClosedError, WebSocketError, ProtocolVersionError, InternalError, } from "../errors.js";
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import { IdAlloc } from "../id_alloc.js";
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import { errorFromProto } from "../result.js";
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import { Sql } from "../sql.js";
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import { impossible } from "../util.js";
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import { WsStream } from "./stream.js";
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import { ClientMsg as json_ClientMsg } from "./json_encode.js";
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import { ClientMsg as protobuf_ClientMsg } from "./protobuf_encode.js";
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import { ServerMsg as json_ServerMsg } from "./json_decode.js";
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import { ServerMsg as protobuf_ServerMsg } from "./protobuf_decode.js";
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export const subprotocolsV2 = new Map([
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["hrana2", { version: 2, encoding: "json" }],
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["hrana1", { version: 1, encoding: "json" }],
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]);
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export const subprotocolsV3 = new Map([
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["hrana3-protobuf", { version: 3, encoding: "protobuf" }],
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["hrana3", { version: 3, encoding: "json" }],
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["hrana2", { version: 2, encoding: "json" }],
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["hrana1", { version: 1, encoding: "json" }],
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]);
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/** A client for the Hrana protocol over a WebSocket. */
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export class WsClient extends Client {
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#socket;
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// List of callbacks that we queue until the socket transitions from the CONNECTING to the OPEN state.
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#openCallbacks;
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// Have we already transitioned from CONNECTING to OPEN and fired the callbacks in #openCallbacks?
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#opened;
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// Stores the error that caused us to close the client (and the socket). If we are not closed, this is
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// `undefined`.
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#closed;
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// Have we received a response to our "hello" from the server?
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#recvdHello;
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// Subprotocol negotiated with the server. It is only available after the socket transitions to the OPEN
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// state.
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#subprotocol;
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// Has the `getVersion()` function been called? This is only used to validate that the API is used
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// correctly.
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#getVersionCalled;
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// A map from request id to the responses that we expect to receive from the server.
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#responseMap;
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// An allocator of request ids.
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#requestIdAlloc;
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// An allocator of stream ids.
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/** @private */
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_streamIdAlloc;
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// An allocator of cursor ids.
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/** @private */
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_cursorIdAlloc;
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// An allocator of SQL text ids.
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#sqlIdAlloc;
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/** @private */
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constructor(socket, jwt) {
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super();
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this.#socket = socket;
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this.#openCallbacks = [];
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this.#opened = false;
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this.#closed = undefined;
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this.#recvdHello = false;
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this.#subprotocol = undefined;
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this.#getVersionCalled = false;
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this.#responseMap = new Map();
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this.#requestIdAlloc = new IdAlloc();
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this._streamIdAlloc = new IdAlloc();
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this._cursorIdAlloc = new IdAlloc();
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this.#sqlIdAlloc = new IdAlloc();
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this.#socket.binaryType = "arraybuffer";
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this.#socket.addEventListener("open", () => this.#onSocketOpen());
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this.#socket.addEventListener("close", (event) => this.#onSocketClose(event));
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this.#socket.addEventListener("error", (event) => this.#onSocketError(event));
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this.#socket.addEventListener("message", (event) => this.#onSocketMessage(event));
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this.#send({ type: "hello", jwt });
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}
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// Send (or enqueue to send) a message to the server.
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#send(msg) {
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if (this.#closed !== undefined) {
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throw new InternalError("Trying to send a message on a closed client");
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}
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if (this.#opened) {
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this.#sendToSocket(msg);
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}
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else {
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const openCallback = () => this.#sendToSocket(msg);
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const errorCallback = () => undefined;
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this.#openCallbacks.push({ openCallback, errorCallback });
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}
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}
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// The socket transitioned from CONNECTING to OPEN
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#onSocketOpen() {
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const protocol = this.#socket.protocol;
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if (protocol === undefined) {
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this.#setClosed(new ClientError("The `WebSocket.protocol` property is undefined. This most likely means that the WebSocket " +
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"implementation provided by the environment is broken. If you are using Miniflare 2, " +
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"please update to Miniflare 3, which fixes this problem."));
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return;
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}
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else if (protocol === "") {
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this.#subprotocol = { version: 1, encoding: "json" };
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}
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else {
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this.#subprotocol = subprotocolsV3.get(protocol);
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if (this.#subprotocol === undefined) {
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this.#setClosed(new ProtoError(`Unrecognized WebSocket subprotocol: ${JSON.stringify(protocol)}`));
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return;
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}
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}
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for (const callbacks of this.#openCallbacks) {
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callbacks.openCallback();
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}
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this.#openCallbacks.length = 0;
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this.#opened = true;
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}
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#sendToSocket(msg) {
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const encoding = this.#subprotocol.encoding;
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if (encoding === "json") {
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const jsonMsg = writeJsonObject(msg, json_ClientMsg);
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this.#socket.send(jsonMsg);
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}
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else if (encoding === "protobuf") {
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const protobufMsg = writeProtobufMessage(msg, protobuf_ClientMsg);
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this.#socket.send(protobufMsg);
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}
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else {
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throw impossible(encoding, "Impossible encoding");
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}
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}
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/** Get the protocol version negotiated with the server, possibly waiting until the socket is open. */
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getVersion() {
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return new Promise((versionCallback, errorCallback) => {
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this.#getVersionCalled = true;
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if (this.#closed !== undefined) {
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errorCallback(this.#closed);
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}
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else if (!this.#opened) {
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const openCallback = () => versionCallback(this.#subprotocol.version);
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this.#openCallbacks.push({ openCallback, errorCallback });
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}
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else {
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versionCallback(this.#subprotocol.version);
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}
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});
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}
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// Make sure that the negotiated version is at least `minVersion`.
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/** @private */
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_ensureVersion(minVersion, feature) {
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if (this.#subprotocol === undefined || !this.#getVersionCalled) {
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throw new ProtocolVersionError(`${feature} is supported only on protocol version ${minVersion} and higher, ` +
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"but the version supported by the WebSocket server is not yet known. " +
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"Use Client.getVersion() to wait until the version is available.");
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}
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else if (this.#subprotocol.version < minVersion) {
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throw new ProtocolVersionError(`${feature} is supported on protocol version ${minVersion} and higher, ` +
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`but the WebSocket server only supports version ${this.#subprotocol.version}`);
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}
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}
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// Send a request to the server and invoke a callback when we get the response.
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/** @private */
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_sendRequest(request, callbacks) {
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if (this.#closed !== undefined) {
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callbacks.errorCallback(new ClosedError("Client is closed", this.#closed));
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return;
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}
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const requestId = this.#requestIdAlloc.alloc();
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this.#responseMap.set(requestId, { ...callbacks, type: request.type });
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this.#send({ type: "request", requestId, request });
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}
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// The socket encountered an error.
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#onSocketError(event) {
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const eventMessage = event.message;
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const message = eventMessage ?? "WebSocket was closed due to an error";
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this.#setClosed(new WebSocketError(message));
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}
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// The socket was closed.
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#onSocketClose(event) {
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let message = `WebSocket was closed with code ${event.code}`;
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if (event.reason) {
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message += `: ${event.reason}`;
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}
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this.#setClosed(new WebSocketError(message));
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}
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// Close the client with the given error.
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#setClosed(error) {
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if (this.#closed !== undefined) {
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return;
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}
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this.#closed = error;
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for (const callbacks of this.#openCallbacks) {
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callbacks.errorCallback(error);
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}
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this.#openCallbacks.length = 0;
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for (const [requestId, responseState] of this.#responseMap.entries()) {
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responseState.errorCallback(error);
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this.#requestIdAlloc.free(requestId);
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}
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this.#responseMap.clear();
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this.#socket.close();
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}
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// We received a message from the socket.
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#onSocketMessage(event) {
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if (this.#closed !== undefined) {
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return;
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}
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try {
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let msg;
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const encoding = this.#subprotocol.encoding;
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if (encoding === "json") {
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if (typeof event.data !== "string") {
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this.#socket.close(3003, "Only text messages are accepted with JSON encoding");
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this.#setClosed(new ProtoError("Received non-text message from server with JSON encoding"));
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return;
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}
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msg = readJsonObject(JSON.parse(event.data), json_ServerMsg);
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}
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else if (encoding === "protobuf") {
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if (!(event.data instanceof ArrayBuffer)) {
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this.#socket.close(3003, "Only binary messages are accepted with Protobuf encoding");
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this.#setClosed(new ProtoError("Received non-binary message from server with Protobuf encoding"));
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return;
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}
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msg = readProtobufMessage(new Uint8Array(event.data), protobuf_ServerMsg);
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}
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else {
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throw impossible(encoding, "Impossible encoding");
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}
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this.#handleMsg(msg);
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}
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catch (e) {
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this.#socket.close(3007, "Could not handle message");
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this.#setClosed(e);
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}
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}
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// Handle a message from the server.
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#handleMsg(msg) {
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if (msg.type === "none") {
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throw new ProtoError("Received an unrecognized ServerMsg");
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}
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else if (msg.type === "hello_ok" || msg.type === "hello_error") {
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if (this.#recvdHello) {
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throw new ProtoError("Received a duplicated hello response");
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}
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this.#recvdHello = true;
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if (msg.type === "hello_error") {
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throw errorFromProto(msg.error);
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}
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return;
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}
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else if (!this.#recvdHello) {
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throw new ProtoError("Received a non-hello message before a hello response");
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}
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if (msg.type === "response_ok") {
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const requestId = msg.requestId;
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const responseState = this.#responseMap.get(requestId);
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this.#responseMap.delete(requestId);
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if (responseState === undefined) {
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throw new ProtoError("Received unexpected OK response");
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}
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this.#requestIdAlloc.free(requestId);
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try {
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if (responseState.type !== msg.response.type) {
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console.dir({ responseState, msg });
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throw new ProtoError("Received unexpected type of response");
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}
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responseState.responseCallback(msg.response);
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}
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catch (e) {
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responseState.errorCallback(e);
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throw e;
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}
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}
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else if (msg.type === "response_error") {
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const requestId = msg.requestId;
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const responseState = this.#responseMap.get(requestId);
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this.#responseMap.delete(requestId);
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if (responseState === undefined) {
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throw new ProtoError("Received unexpected error response");
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}
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this.#requestIdAlloc.free(requestId);
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responseState.errorCallback(errorFromProto(msg.error));
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}
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else {
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throw impossible(msg, "Impossible ServerMsg type");
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}
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}
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/** Open a {@link WsStream}, a stream for executing SQL statements. */
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openStream() {
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return WsStream.open(this);
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}
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/** Cache a SQL text on the server. This requires protocol version 2 or higher. */
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storeSql(sql) {
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this._ensureVersion(2, "storeSql()");
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const sqlId = this.#sqlIdAlloc.alloc();
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const sqlObj = new Sql(this, sqlId);
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const responseCallback = () => undefined;
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const errorCallback = (e) => sqlObj._setClosed(e);
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const request = { type: "store_sql", sqlId, sql };
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this._sendRequest(request, { responseCallback, errorCallback });
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return sqlObj;
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}
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/** @private */
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_closeSql(sqlId) {
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if (this.#closed !== undefined) {
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return;
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}
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const responseCallback = () => this.#sqlIdAlloc.free(sqlId);
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const errorCallback = (e) => this.#setClosed(e);
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const request = { type: "close_sql", sqlId };
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this._sendRequest(request, { responseCallback, errorCallback });
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}
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/** Close the client and the WebSocket. */
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close() {
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this.#setClosed(new ClientError("Client was manually closed"));
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}
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/** True if the client is closed. */
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get closed() {
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return this.#closed !== undefined;
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}
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}
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