ethernet-ip/dist/cip/message-router.js

A feature-complete EtherNet/IP client for Rockwell ControlLogix/CompactLogix PLCs

"use strict";
/**
 * CIP Message Router — build requests and parse responses.
 * Per CIP Vol 1, Chapter 2
 *
 * Request:
 *   [service(1), pathSize(1), path(N), data(M)]
 *
 * Response:
 *   [service|0x80(1), reserved(1), status(1), extStatusSize(1), extStatus(K), data(M)]
 */
Object.defineProperty(exports, "__esModule", { value: true });
exports.build = build;
exports.parse = parse;
/**
 * Build a Message Router request.
 *
 * @param service - CIP service code
 * @param path    - Padded EPATH (from EPathBuilder)
 * @param data    - Service-specific request data
 */
function build(service, path, data = Buffer.alloc(0)) {
    // Path size in 16-bit words
    const pathWords = Math.ceil(path.length / 2);
    const pathBytes = pathWords * 2;
    const buf = Buffer.alloc(2 + pathBytes + data.length);
    buf.writeUInt8(service, 0); // Service code
    buf.writeUInt8(pathWords, 1); // Path size (words)
    path.copy(buf, 2); // Padded EPATH
    data.copy(buf, 2 + pathBytes); // Service data
    return buf;
}
/**
 * Parse a Message Router response.
 */
function parse(buf) {
    const service = buf.readUInt8(0); // Reply service (request | 0x80)
    // byte 1 reserved
    const generalStatusCode = buf.readUInt8(2);
    const extendedStatusLength = buf.readUInt8(3); // In 16-bit words
    // Extended status: array of UINT16LE
    const extendedStatus = [];
    for (let i = 0; i < extendedStatusLength; i++) {
        extendedStatus.push(buf.readUInt16LE(4 + i * 2));
    }
    // Data follows extended status
    const dataOffset = 4 + extendedStatusLength * 2;
    const data = buf.subarray(dataOffset);
    return { service, generalStatusCode, extendedStatusLength, extendedStatus, data };
}
//# sourceMappingURL=message-router.js.map