55 lines
1.7 KiB
JavaScript
55 lines
1.7 KiB
JavaScript
import { ERROR_PACKET, PACKET_TYPES_REVERSE, } from "./commons.js";
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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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const buffer = Buffer.from(encodedPacket.substring(1), "base64");
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return {
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type: "message",
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data: mapBinary(buffer, binaryType),
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};
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}
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if (!PACKET_TYPES_REVERSE[type]) {
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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 mapBinary = (data, binaryType) => {
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switch (binaryType) {
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case "arraybuffer":
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if (data instanceof ArrayBuffer) {
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// from WebSocket & binaryType "arraybuffer"
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return data;
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}
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else if (Buffer.isBuffer(data)) {
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// from HTTP long-polling
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return data.buffer.slice(data.byteOffset, data.byteOffset + data.byteLength);
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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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case "nodebuffer":
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default:
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if (Buffer.isBuffer(data)) {
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// from HTTP long-polling or WebSocket & binaryType "nodebuffer" (default)
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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 Buffer.from(data);
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}
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}
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};
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