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kamilogorek/pglite-protocol.mjs

Created March 30, 2024 17:02
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  1. kamilogorek renamed this gist Mar 30, 2024. 1 changed file with 0 additions and 0 deletions.
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  2. kamilogorek created this gist Mar 30, 2024.
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    <img width="790" alt="318211964-15ed93a1-0d07-43ef-a9f6-9c87172252b5" src="https://gist.github.com/assets/1523305/0eecb45c-f054-4651-a6ed-df97ec1a4a06">
    102 changes: 102 additions & 0 deletions pglite-protocol.mjs
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    import { createServer } from "node:net";
    import { PGlite } from "@electric-sql/pglite";

    const PORT = 5432;

    const db = new PGlite();
    await db.exec(`
    CREATE TABLE IF NOT EXISTS test (
    id SERIAL PRIMARY KEY,
    name TEXT
    );
    INSERT INTO test (name) VALUES ('test');
    `);

    function isSSLRequest(buffer) {
    return (
    buffer.at(4) === 0x04 &&
    buffer.at(5) === 0xd2 &&
    buffer.at(6) === 0x16 &&
    buffer.at(7) === 0x2f
    );
    }

    function isStartupMessage(buffer) {
    return (
    buffer.at(4) === 0x00 &&
    buffer.at(5) === 0x03 &&
    buffer.at(6) === 0x00 &&
    buffer.at(7) === 0x00
    );
    }

    function isExitMessage(buffer) {
    return buffer.at(0) === 0x58; // 'X'
    }

    function isQueryMessage(buffer) {
    return buffer.at(0) === 0x51; // 'Q'
    }

    const server = createServer();

    server.on("connection", function (socket) {
    const clientAddr = `${socket.remoteAddress}:${socket.remotePort}`;

    console.log(`Client connected: ${clientAddr}`);

    // https://www.postgresql.org/docs/current/protocol-message-formats.html
    socket.on("data", async (data) => {
    if (isSSLRequest(data)) {
    // SSL negotiation
    const sslNegotiation = Buffer.alloc(1);
    sslNegotiation.write("N");
    socket.write(sslNegotiation);
    } else if (isStartupMessage(data)) {
    // AuthenticationOk
    const authOk = Buffer.alloc(9);
    authOk.write("R"); // 'R' for AuthenticationOk
    authOk.writeInt8(8, 4); // Length
    authOk.writeInt8(0, 7); // AuthenticationOk

    // BackendKeyData
    const backendKeyData = Buffer.alloc(13);
    backendKeyData.write("K"); // Message type
    backendKeyData.writeInt8(12, 4); // Message length
    backendKeyData.writeInt16BE(1234, 7); // Process ID
    backendKeyData.writeInt16BE(5679, 11); // Secret key

    // ReadyForQuery
    const readyForQuery = Buffer.alloc(6);
    readyForQuery.write("Z"); // 'Z' for ReadyForQuery
    readyForQuery.writeInt8(5, 4); // Length
    readyForQuery.write("I", 5); // Transaction status indicator, 'I' for idle

    socket.write(Buffer.concat([authOk, backendKeyData, readyForQuery]));
    } else if (isExitMessage(data)) {
    socket.end();
    } else if (isQueryMessage(data)) {
    const result = await db.execProtocol(data);
    socket.write(Buffer.concat(result.map(([_, buffer]) => buffer)));
    } else {
    console.log("Unknown message:", data);
    }
    });

    socket.on("end", () => {
    console.log(`Client disconnected: ${clientAddr}`);
    });

    socket.on("error", (err) => {
    console.log(`Client ${clientAddr} error:`, err);
    socket.end();
    });
    });

    server.on("error", (err) => {
    console.log(`Server error:`, err);
    });

    server.listen(PORT, () => {
    console.log(`Server bound to port ${PORT}`);
    });