✨ Add Firebase node (#1173)

* ⚡ Added node for Google firebase Firestore database

* ⚡ added firebase's realtime database node

* Added operation to run queries on documents collection

* Improvements to Firebase Database nodes
- Realtime Database: improved how the node interacts with input database
- Cloud Firestore: improved how the node interacts with input database
- Cloud Firestore: improved input / output format so it's similar to JSON and more intuitive, abstracting Firestore's format

* ⚡ Improvements to Firestore-Node

* ⚡ improvements to Firebase-Node

* ⚡ Improvements

⚡ Improvements

* ⚡ Improvements

* ⚡ Minor improvements to Firebase Nodes

Co-authored-by: Omar Ajoue <krynble@gmail.com>
Co-authored-by: ricardo <ricardoespinoza105@gmail.com>

packages/nodes-base/nodes/Google/Firebase/CloudFirestore/GenericFunctions.ts

@@ -0,0 +1,153 @@
+import {
+	OptionsWithUri,
+} from 'request';
+
+import {
+	IExecuteFunctions,
+	IExecuteSingleFunctions,
+	ILoadOptionsFunctions,
+} from 'n8n-core';
+
+import {
+	IDataObject,
+} from 'n8n-workflow';
+
+export async function googleApiRequest(this: IExecuteFunctions | IExecuteSingleFunctions | ILoadOptionsFunctions, method: string, resource: string, body: any = {}, qs: IDataObject = {}, uri: string | null = null): Promise<any> { // tslint:disable-line:no-any
+
+	const options: OptionsWithUri = {
+		headers: {
+			'Content-Type': 'application/json',
+		},
+		method,
+		body,
+		qs,
+		qsStringifyOptions: {
+			arrayFormat: 'repeat',
+		},
+		uri: uri || `https://firestore.googleapis.com/v1/projects${resource}`,
+		json: true,
+	};
+	try {
+		if (Object.keys(body).length === 0) {
+			delete options.body;
+		}
+
+		//@ts-ignore
+		return await this.helpers.requestOAuth2.call(this, 'googleFirebaseCloudFirestoreOAuth2Api', options);
+	} catch (error) {
+		let errors;
+
+		if (error.response && error.response.body) {
+
+			if (Array.isArray(error.response.body)) {
+
+				errors = error.response.body;
+
+				errors = errors.map((e: { error: { message: string } }) => e.error.message).join('|');
+			} else {
+				errors = error.response.body.error.message;
+			}
+
+			// Try to return the error prettier
+			throw new Error(
+				`Google Firebase error response [${error.statusCode}]: ${errors}`,
+			);
+		}
+		throw error;
+	}
+}
+
+export async function googleApiRequestAllItems(this: IExecuteFunctions | ILoadOptionsFunctions, propertyName: string, method: string, endpoint: string, body: any = {}, query: IDataObject = {}, uri: string | null = null): Promise<any> { // tslint:disable-line:no-any
+
+	const returnData: IDataObject[] = [];
+
+	let responseData;
+	query.pageSize = 100;
+
+	do {
+		responseData = await googleApiRequest.call(this, method, endpoint, body, query, uri);
+		query.pageToken = responseData['nextPageToken'];
+		returnData.push.apply(returnData, responseData[propertyName]);
+	} while (
+		responseData['nextPageToken'] !== undefined &&
+		responseData['nextPageToken'] !== ''
+	);
+
+	return returnData;
+}
+
+
+// Both functions below were taken from Stack Overflow jsonToDocument was fixed as it was unable to handle null values correctly
+// https://stackoverflow.com/questions/62246410/how-to-convert-a-firestore-document-to-plain-json-and-vice-versa
+// Great thanks to https://stackoverflow.com/users/3915246/mahindar
+export function jsonToDocument(value: string | number | IDataObject | IDataObject[]): IDataObject {
+	if (value === 'true' || value === 'false' || typeof value === 'boolean') {
+		return { 'booleanValue': value };
+	} else if (value === null) {
+		return { 'nullValue': null };
+	} else if (!isNaN(value as number)) {
+		if (value.toString().indexOf('.') !== -1) {
+			return { 'doubleValue': value };
+		} else {
+			return { 'integerValue': value };
+		}
+	} else if (Date.parse(value as string)) {
+		const date = new Date(Date.parse(value as string));
+		return { 'timestampValue': date.toISOString() };
+	} else if (typeof value === 'string') {
+		return { 'stringValue': value };
+	} else if (value && value.constructor === Array) {
+		return { 'arrayValue': { values: value.map(v => jsonToDocument(v)) } };
+	} else if (typeof value === 'object') {
+		const obj = {};
+		for (const o of Object.keys(value)) {
+			//@ts-ignore
+			obj[o] = jsonToDocument(value[o]);
+		}
+		return { 'mapValue': { fields: obj } };
+	}
+
+	return {};
+}
+
+export function fullDocumentToJson(data: IDataObject): IDataObject {
+	if (data === undefined) {
+		return data;
+	}
+
+	return {
+		_name: data.name,
+		_createTime: data.createTime,
+		_updateTime: data.updateTime,
+		...documentToJson(data.fields as IDataObject),
+	};
+}
+
+
+export function documentToJson(fields: IDataObject): IDataObject {
+	const result = {};
+	for (const f of Object.keys(fields)) {
+		const key = f, value = fields[f],
+			isDocumentType = ['stringValue', 'booleanValue', 'doubleValue',
+				'integerValue', 'timestampValue', 'mapValue', 'arrayValue'].find(t => t === key);
+		if (isDocumentType) {
+			const item = ['stringValue', 'booleanValue', 'doubleValue', 'integerValue', 'timestampValue']
+				.find(t => t === key);
+			if (item) {
+				return value as IDataObject;
+			} else if ('mapValue' === key) {
+				//@ts-ignore
+				return documentToJson(value!.fields || {});
+			} else if ('arrayValue' === key) {
+				// @ts-ignore
+				const list = value.values as IDataObject[];
+				// @ts-ignore
+				return !!list ? list.map(l => documentToJson(l)) : [];
+			}
+		} else {
+			// @ts-ignore
+			result[key] = documentToJson(value);
+		}
+	}
+	return result;
+}