feat(Mautic Node): Add credential test and allow trailing slash in host (#3080)

* Updated Mautic to stop trailing slashes from causing an issue

* Fixed oauth failing when there is a trailing slash in the mautic host

* Added credential test

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

@@ -10,7 +10,11 @@ import {
 } from 'n8n-core';
 
 import {
-	IDataObject, JsonObject, NodeApiError,
+	ICredentialDataDecryptedObject,
+	ICredentialTestFunctions,
+	IDataObject,
+	JsonObject,
+	NodeApiError,
 } from 'n8n-workflow';
 
 export async function mauticApiRequest(this: IHookFunctions | IExecuteFunctions | IExecuteSingleFunctions | ILoadOptionsFunctions, method: string, endpoint: string, body: any = {}, query?: IDataObject, uri?: string): Promise<any> { // tslint:disable-line:no-any
@@ -31,19 +35,21 @@ export async function mauticApiRequest(this: IHookFunctions | IExecuteFunctions
 
 		if (authenticationMethod === 'credentials') {
 			const credentials = await this.getCredentials('mauticApi') as IDataObject;
+			const baseUrl = credentials!.url as string;
 
 			const base64Key = Buffer.from(`${credentials.username}:${credentials.password}`).toString('base64');
 
 			options.headers!.Authorization = `Basic ${base64Key}`;
 
-			options.uri = `${credentials.url}${options.uri}`;
+			options.uri = `${baseUrl.endsWith('/') ? baseUrl.slice(0, -1) : baseUrl}${options.uri}`;
 
 			//@ts-ignore
 			returnData = await this.helpers.request(options);
 		} else {
 			const credentials = await this.getCredentials('mauticOAuth2Api') as IDataObject;
+			const baseUrl = credentials!.url as string;
 
-			options.uri = `${credentials.url}${options.uri}`;
+			options.uri = `${baseUrl.endsWith('/') ? baseUrl.slice(0, -1) : baseUrl}${options.uri}`;
 			//@ts-ignore
 			returnData = await this.helpers.requestOAuth2.call(this, 'mauticOAuth2Api', options, { includeCredentialsOnRefreshOnBody: true });
 		}
@@ -96,3 +102,30 @@ export function validateJSON(json: string | undefined): any { // tslint:disable-
 	}
 	return result;
 }
+
+export async function validateCredentials(this: ICredentialTestFunctions, decryptedCredentials: ICredentialDataDecryptedObject): Promise<any> { // tslint:disable-line:no-any
+	const credentials = decryptedCredentials;
+
+	const {
+		url,
+		username,
+		password,
+	} = credentials as {
+		url: string,
+		username: string,
+		password: string,
+	};
+
+	const base64Key = Buffer.from(`${username}:${password}`).toString('base64');
+
+	const options: OptionsWithUri = {
+		method: 'GET',
+		headers: {
+			Authorization: `Basic ${base64Key}`,
+		},
+		uri: url.endsWith('/') ? `${url}api/users/self` : `${url}/api/users/self`,
+		json: true,
+	};
+
+	return await this.helpers.request(options);
+}