Implement longSms processor

src/PDUProcessor/Preprocessor/Client/LongSmsProcessor.ts

@@ -0,0 +1,80 @@
+import {PDU} from "../../../CommonObjects";
+import SmppSession from "../../../SmppSession";
+import Preprocessor from "../Preprocessor";
+
+const smpp = require('smpp');
+
+export default class LongSmsProcessor extends Preprocessor {
+	private iterator: number = 0;
+
+	constructor(type: string) {
+		// An sms can have a maximum length (short_message) of 1120 bits or 140 bytes.
+		// For a message encoded in UCS-2, the maximum length is 70 characters. (2 bytes per character)
+		// For a message encoded in GSM-7, the maximum length is 160 characters. (7 bits per character)
+		// Once a message is split the part information is placed into udh
+		// Like
+		// destination_addr: config.destinationAddress,
+		// short_message: {
+		//   udh: Buffer.from([0x05, 0x00, 0x03, 0x05, 0x02, 0x01]),
+		//   message: "Hello World!"
+		// }
+		// The UDH parameters are as follows:
+		// 0x05: Length of UDH (5 bytes to follow)
+		// 0x00: Concatenated message Information Element (8-bit reference number)
+		// 0x03: Length of Information Element data (3 bytes to follow)
+		// 0xXX: Reference number for this concatenated message
+		// 0xYY: Number of fragments in the concatenated message
+		// 0xZZ: Fragment number/index within the concatenated message 1072
+		super(type);
+	}
+
+	processPdu(session: any, pdu: PDU, entity?: SmppSession | undefined): Promise<any> {
+		return new Promise<any>((resolve, reject) => {
+			if (!!pdu.short_message) {
+				let encoding: number | undefined = pdu.data_coding;
+				if (!encoding) {
+					encoding = 0;
+				}
+				let characterSizeBits: number = 0;
+				switch (encoding) {
+					case 0:
+					case 1:
+						characterSizeBits = 8;
+						break;
+					case 8:
+						characterSizeBits = 16;
+						break;
+				}
+				if (characterSizeBits) {
+					let splitMessage: string[] = [];
+					let message: string = pdu.short_message;
+					let messageLength: number = message.length;
+					let maxMessageLength: number = 1072 / characterSizeBits;
+					let messageCount: number = Math.ceil(messageLength / maxMessageLength);
+					for (let i = 0; i < messageCount; i++) {
+						splitMessage.push(message.substr(i * maxMessageLength, maxMessageLength));
+					}
+
+					splitMessage.forEach((messagePart: string, index: number) => {
+						let udh: Buffer = Buffer.from([0x05, 0x00, 0x03, this.iterator++, messageCount, index + 1]);
+
+						if (index < (messageCount - 1)) {
+							let partPdu = new smpp.PDU(pdu.command, {...pdu});
+							partPdu.short_message = {
+								udh: udh,
+								message: messagePart
+							}
+							entity?.doSendPdu(partPdu, session);
+						} else {
+							pdu.short_message = {
+								udh: udh,
+								message: messagePart
+							}
+							resolve(pdu);
+						}
+					});
+				}
+			}
+		});
+	}
+}