✨ Add DHL node (#2385)

* ✨ DHL node

* ⚡ Add credentials verfication

* 👕 Nodelinter pass

* ⚡ Improvements

* ⚡ Fix node name

Co-authored-by: Iván Ovejero <ivov.src@gmail.com>
Co-authored-by: Jan Oberhauser <jan.oberhauser@gmail.com>

packages/nodes-base/nodes/Dhl/GenericFunctions.ts

@@ -0,0 +1,65 @@
+import {
+	OptionsWithUri,
+} from 'request';
+
+import {
+	IExecuteFunctions,
+	IExecuteSingleFunctions,
+	IHookFunctions,
+	ILoadOptionsFunctions,
+} from 'n8n-core';
+
+import {
+	ICredentialDataDecryptedObject,
+	ICredentialTestFunctions,
+	IDataObject,
+	NodeApiError,
+} from 'n8n-workflow';
+
+export async function dhlApiRequest(this: IHookFunctions | IExecuteFunctions | IExecuteSingleFunctions | ILoadOptionsFunctions, method: string, path: string, body: any = {}, qs: IDataObject = {}, uri?: string, option: IDataObject = {}): Promise<any> { // tslint:disable-line:no-any
+
+	const credentials = await this.getCredentials('dhlApi') as { apiKey: string };
+
+	let options: OptionsWithUri = {
+		headers: {
+			'DHL-API-Key': credentials.apiKey,
+		},
+		method,
+		qs,
+		body,
+		uri: uri || `https://api-eu.dhl.com${path}`,
+		json: true,
+	};
+	options = Object.assign({}, options, option);
+	if (Object.keys(options.body).length === 0) {
+		delete options.body;
+	}
+
+	try {
+		return await this.helpers.request!(options);
+	} catch (error) {
+		throw new NodeApiError(this.getNode(), error);
+	}
+}
+
+export async function validateCrendetials(this: ICredentialTestFunctions, decryptedCredentials: ICredentialDataDecryptedObject): Promise<any> { // tslint:disable-line:no-any
+	const credentials = decryptedCredentials;
+
+	const { apiKey } = credentials as {
+		apiKey: string,
+	};
+
+	const options: OptionsWithUri = {
+		headers: {
+			'DHL-API-Key': apiKey,
+		},
+		qs: {
+			trackingNumber: 123,
+		},
+		method: 'GET',
+		uri: `https://api-eu.dhl.com/track/shipments`,
+		json: true,
+	};
+
+	return this.helpers.request!(options);
+}