✨ Gmail node (#856)

* ✨ Gmail node

* ⚡ Improvements

* ⚡ Improvements

* ⚡ Improvements to Gmail-Node

* ⚡ Additional improvements to Gmail-Node

Co-authored-by: Erin <erin2722@gmail.com>
Co-authored-by: ricardo <ricardoespinoza105@gmail.com>

packages/nodes-base/nodes/Google/Gmail/GenericFunctions.ts

@@ -0,0 +1,191 @@
+import {
+	OptionsWithUri,
+} from 'request';
+
+import {
+	simpleParser,
+	Source as ParserSource,
+} from 'mailparser';
+
+import {
+	IExecuteFunctions,
+	IExecuteSingleFunctions,
+	ILoadOptionsFunctions,
+} from 'n8n-core';
+
+import {
+	IBinaryKeyData,
+	IDataObject,
+	INodeExecutionData,
+} from 'n8n-workflow';
+
+import {
+	IEmail,
+} from './Gmail.node';
+
+export async function googleApiRequest(this: IExecuteFunctions | IExecuteSingleFunctions | ILoadOptionsFunctions, method: string,
+	endpoint: string, body: any = {}, qs: IDataObject = {}, uri?: string, option: IDataObject = {}): Promise<any> { // tslint:disable-line:no-any
+	let options: OptionsWithUri = {
+		headers: {
+			'Accept': 'application/json',
+			'Content-Type': 'application/json',
+		},
+		method,
+		body,
+		qs,
+		uri: uri || `https://www.googleapis.com${endpoint}`,
+		json: true,
+	};
+
+	options = Object.assign({}, options, option);
+
+	try {
+		if (Object.keys(body).length === 0) {
+			delete options.body;
+		}
+
+		//@ts-ignore
+		return await this.helpers.requestOAuth2.call(this, 'gmailOAuth2', options);
+
+	} catch (error) {
+		if (error.response && error.response.body && error.response.body.error) {
+
+			let errorMessages;
+
+			if (error.response.body.error.errors) {
+				// Try to return the error prettier
+				errorMessages = error.response.body.error.errors;
+
+				errorMessages = errorMessages.map((errorItem: IDataObject) => errorItem.message);
+
+				errorMessages = errorMessages.join('|');
+
+			} else if (error.response.body.error.message) {
+				errorMessages = error.response.body.error.message;
+			}
+
+			throw new Error(`Gmail error response [${error.statusCode}]: ${errorMessages}`);
+		}
+		throw error;
+	}
+}
+
+
+export async function parseRawEmail(this: IExecuteFunctions, messageEncoded: ParserSource, dataPropertyNameDownload: string): Promise<INodeExecutionData> {
+
+	const responseData = await simpleParser(messageEncoded);
+
+	const headers: IDataObject = {};
+	for (const header of responseData.headerLines) {
+		headers[header.key] = header.line;
+	}
+
+	// @ts-ignore
+	responseData.headers = headers;
+	// @ts-ignore
+	responseData.headerLines = undefined;
+
+	const binaryData: IBinaryKeyData = {};
+	if (responseData.attachments) {
+
+		for (let i = 0; i < responseData.attachments.length; i++) {
+			const attachment = responseData.attachments[i];
+			binaryData[`${dataPropertyNameDownload}${i}`] = await this.helpers.prepareBinaryData(attachment.content, attachment.filename, attachment.contentType);
+		}
+		// @ts-ignore
+		responseData.attachments = undefined;
+	}
+
+	return {
+		json: responseData as unknown as IDataObject,
+		binary: Object.keys(binaryData).length ? binaryData : undefined,
+	} as INodeExecutionData;
+}
+
+
+//------------------------------------------------------------------------------------------------------------------------------------------
+// This function converts an email object into a MIME encoded email and then converts that string into base64 encoding
+// for more info on MIME, https://docs.microsoft.com/en-us/previous-versions/office/developer/exchange-server-2010/aa494197(v%3Dexchg.140)
+//------------------------------------------------------------------------------------------------------------------------------------------
+
+export function encodeEmail(email: IEmail) {
+	let mimeEmail = '';
+
+	if (email.attachments !== undefined && email.attachments !== []) {
+		const attachments = email.attachments.map((attachment) => {
+			return [
+				"--XXXXboundary text\n",
+				"Content-Type:", attachment.type, ";\n",
+				"Content-Transfer-Encoding: Base64\n",
+				"Content-Disposition: attachment;\n",
+				"\tfilename=\"", attachment.name, "\"\n\n",
+
+				attachment.content, "\n\n",
+
+				"--XXXXboundary text\n\n",
+			].join('');
+		});
+
+		mimeEmail = [
+			"To: ", email.to, "\n",
+			"Cc: ", email.cc, "\n",
+			"Bcc: ", email.bcc, "\n",
+			"In-Reply-To: ", email.inReplyTo, "\n",
+			"References: ", email.reference, "\n",
+			"Subject: ", email.subject, "\n",
+			"MIME-Version: 1.0\n",
+			"Content-Type: multipart/mixed;\n",
+			"\tboundary=\"XXXXboundary text\"\n\n",
+
+			"This is a multipart message in MIME format.\n\n",
+
+			"--XXXXboundary text\n",
+			"Content-Type: text/plain\n\n",
+
+			email.body, "\n\n",
+
+			attachments.join(''),
+
+			"--XXXXboundary text--",
+		].join('');
+	} else {
+		mimeEmail = [
+			"Content-Type: text/plain; charset=\"UTF-8\"\n",
+			"MIME-Version: 1.0\n",
+			"Content-Transfer-Encoding: 7bit\n",
+			"To: ", email.to, "\n",
+			"Cc: ", email.cc, "\n",
+			"Bcc: ", email.bcc, "\n",
+			"In-Reply-To: ", email.inReplyTo, "\n",
+			"References: ", email.reference, "\n",
+			"Subject: ", email.subject, "\n\n",
+			email.body,
+		].join('');
+	}
+
+	return Buffer.from(mimeEmail).toString("base64").replace(/\+/g, '-').replace(/\//g, '_');
+}
+
+export async function googleApiRequestAllItems(this: IExecuteFunctions | ILoadOptionsFunctions, propertyName: string, method: string, endpoint: string, body: any = {}, query: IDataObject = {}): Promise<any> { // tslint:disable-line:no-any
+
+	const returnData: IDataObject[] = [];
+
+	let responseData;
+	query.maxResults = 100;
+
+	do {
+		responseData = await googleApiRequest.call(this, method, endpoint, body, query);
+		query.pageToken = responseData['nextPageToken'];
+		returnData.push.apply(returnData, responseData[propertyName]);
+	} while (
+		responseData['nextPageToken'] !== undefined &&
+		responseData['nextPageToken'] !== ''
+	);
+
+	return returnData;
+}
+
+export function extractEmail(s: string) {
+	const data = s.split('<')[1];
+	return data.substring(0, data.length - 1);
+}