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63 lines
1.9 KiB
JavaScript
63 lines
1.9 KiB
JavaScript
import { ERROR_PACKET, PACKET_TYPES_REVERSE, } from "./commons.js";
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import { decode } from "./contrib/base64-arraybuffer.js";
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const withNativeArrayBuffer = typeof ArrayBuffer === "function";
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export const decodePacket = (encodedPacket, binaryType) => {
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if (typeof encodedPacket !== "string") {
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return {
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type: "message",
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data: mapBinary(encodedPacket, binaryType),
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};
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}
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const type = encodedPacket.charAt(0);
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if (type === "b") {
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return {
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type: "message",
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data: decodeBase64Packet(encodedPacket.substring(1), binaryType),
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};
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}
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const packetType = PACKET_TYPES_REVERSE[type];
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if (!packetType) {
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return ERROR_PACKET;
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}
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return encodedPacket.length > 1
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? {
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type: PACKET_TYPES_REVERSE[type],
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data: encodedPacket.substring(1),
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}
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: {
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type: PACKET_TYPES_REVERSE[type],
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};
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};
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const decodeBase64Packet = (data, binaryType) => {
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if (withNativeArrayBuffer) {
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const decoded = decode(data);
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return mapBinary(decoded, binaryType);
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}
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else {
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return { base64: true, data }; // fallback for old browsers
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}
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};
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const mapBinary = (data, binaryType) => {
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switch (binaryType) {
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case "blob":
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if (data instanceof Blob) {
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// from WebSocket + binaryType "blob"
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return data;
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}
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else {
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// from HTTP long-polling or WebTransport
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return new Blob([data]);
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}
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case "arraybuffer":
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default:
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if (data instanceof ArrayBuffer) {
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// from HTTP long-polling (base64) or WebSocket + binaryType "arraybuffer"
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return data;
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}
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else {
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// from WebTransport (Uint8Array)
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return data.buffer;
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}
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}
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};
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