chore(download): Add support for segmented download

lib/Client.js

@@ -147,22 +147,43 @@ module.exports = class Client {
 	async download(order) {
 		if (this.tracesStorage)
 			this.tracesStorage.new().ofType('ORDER.DOWNLOAD');
-		const res = await this.ebicsRequest(order);
+
+		const orderData = [];
+
+		let res = await this.ebicsRequest(order);
+		let transactionKey = res.transactionKey();
 
 		order.transactionId = res.transactionId();
+		order.segmentNumber = res.segmentNumber();
+
+		if (res.orderData()) orderData.push(res.orderData());
+
+		// In case of multi-segment download transaction is
+		// usually supplied during INITIALISATION phase,
+		// whereas the actual data is delivered in following segments
+		while (res.isSegmented() && !res.isLastSegment()) {
+			order.segmentNumber = res.segmentNumber() + 1;
+
+			res = await this.ebicsRequest(order);
+			transactionKey = transactionKey || res.transactionKey();
+			res.obtainedTransactionKey = transactionKey;
+
+			if (res.orderData()) orderData.push(res.orderData());
+		}
 
 		if (res.isSegmented() && res.isLastSegment()) {
 			if (this.tracesStorage)
 				this.tracesStorage.connect().ofType('RECEIPT.ORDER.DOWNLOAD');
 
+			order.segmentNumber = null; // Clear segment number for receipt request
 			await this.ebicsRequest(order);
 		}
 
 		const returnedTechnicalCode = res.technicalCode();
 		const returnedBusinessCode = res.businessCode();
 
 		return {
-			orderData: res.orderData(),
+			orderData: orderData.length === 1 ? orderData[0] : orderData, // backward compatibility
 			orderId: res.orderId(),
 
 			technicalCode: returnedTechnicalCode,

lib/orders/H004/response.js

@@ -22,6 +22,7 @@ const lastChild = (node) => {
 module.exports = (xml, keys) => ({
 	keys,
 	doc: new DOMParser().parseFromString(xml, 'text/xml'),
+	obtainedTransactionKey: null,
 
 	isSegmented() {
 		const select = xpath.useNamespaces({ xmlns: 'urn:org:ebics:H004' });
@@ -30,6 +31,13 @@ module.exports = (xml, keys) => ({
 		return !!node.length;
 	},
 
+	segmentNumber() {
+		const select = xpath.useNamespaces({ xmlns: 'urn:org:ebics:H004' });
+		const node = select('//xmlns:header/xmlns:mutable/xmlns:SegmentNumber', this.doc);
+
+		return node.length ? Number.parseInt(node[0].textContent, 10) : null;
+	},
+
 	isLastSegment() {
 		const select = xpath.useNamespaces({ xmlns: 'urn:org:ebics:H004' });
 		const node = select("//xmlns:header/xmlns:mutable/*[@lastSegment='true']", this.doc);
@@ -40,7 +48,7 @@ module.exports = (xml, keys) => ({
 	orderData() {
 		const orderDataNode = this.doc.getElementsByTagNameNS('urn:org:ebics:H004', 'OrderData');
 
-		if (!orderDataNode.length) return {};
+		if (!orderDataNode.length) return null;
 
 		const orderData = orderDataNode[0].textContent;
 		const decipher = crypto.createDecipheriv('aes-128-cbc', this.transactionKey(), DEFAULT_IV).setAutoPadding(false);
@@ -50,6 +58,7 @@ module.exports = (xml, keys) => ({
 	},
 
 	transactionKey() {
+		if (this.obtainedTransactionKey) return this.obtainedTransactionKey;
 		const keyNodeText = this.doc.getElementsByTagNameNS('urn:org:ebics:H004', 'TransactionKey')[0].textContent;
 		return Crypto.privateDecrypt(this.keys.e(), Buffer.from(keyNodeText, 'base64'));
 	},

lib/orders/H004/serializers/download.js

@@ -13,7 +13,7 @@ module.exports = {
 			userId: client.userId,
 			hostId: client.hostId,
 		};
-		const { orderDetails, transactionId } = order;
+		const { orderDetails, transactionId, segmentNumber } = order;
 		const {
 			rootName, xmlOptions, xmlSchema, receipt, transfer, productString,
 		} = genericSerializer(client.hostId, transactionId);
@@ -25,35 +25,46 @@ module.exports = {
 		this.receipt = receipt;
 		this.transfer = transfer;
 
-		if (transactionId) return this.receipt();
+		if (!segmentNumber && transactionId) return this.receipt();
 
 		this.xmlSchema.header = {
 			'@': { authenticate: true },
 			static: {
 				HostID: ebicsAccount.hostId,
-				Nonce: Crypto.nonce(),
-				Timestamp: Crypto.timestamp(),
-				PartnerID: ebicsAccount.partnerId,
-				UserID: ebicsAccount.userId,
-				Product: {
-					'@': { Language: 'en' },
-					'#': productString,
-				},
-				OrderDetails: orderDetails,
-				BankPubKeyDigests: {
-					Authentication: {
-						'@': { Version: 'X002', Algorithm: 'http://www.w3.org/2001/04/xmlenc#sha256' },
-						'#': Crypto.digestPublicKey(keys.bankX()),
+				...!transactionId && {
+					Nonce: Crypto.nonce(),
+					Timestamp: Crypto.timestamp(),
+					PartnerID: ebicsAccount.partnerId,
+					UserID: ebicsAccount.userId,
+					Product: {
+						'@': { Language: 'en' },
+						'#': productString,
 					},
-					Encryption: {
-						'@': { Version: 'E002', Algorithm: 'http://www.w3.org/2001/04/xmlenc#sha256' },
-						'#': Crypto.digestPublicKey(keys.bankE()),
+					OrderDetails: orderDetails,
+					BankPubKeyDigests: {
+						Authentication: {
+							'@': { Version: 'X002', Algorithm: 'http://www.w3.org/2001/04/xmlenc#sha256' },
+							'#': Crypto.digestPublicKey(keys.bankX()),
+						},
+						Encryption: {
+							'@': { Version: 'E002', Algorithm: 'http://www.w3.org/2001/04/xmlenc#sha256' },
+							'#': Crypto.digestPublicKey(keys.bankE()),
+						},
 					},
+					SecurityMedium: '0000',
+				},
+				...transactionId && {
+					TransactionID: transactionId,
 				},
-				SecurityMedium: '0000',
 			},
 			mutable: {
-				TransactionPhase: 'Initialisation',
+				TransactionPhase: segmentNumber ? 'Transfer' : 'Initialisation',
+				...segmentNumber && {
+					SegmentNumber: {
+						'@': { lastSegment: false },
+						'#': segmentNumber,
+					},
+				},
 			},
 		};