Merge pull request #1 from Athaphian/mocks-generation

Mocks generation
Athaphian · Jun 5, 2018 · 4a18d17 · 4a18d17
2 parents 286e815 + eaa9f62
commit 4a18d17
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Showing 4 changed files with 142 additions and 56 deletions.
diff --git a/modules/jsonFetch.js b/modules/jsonFetch.js
@@ -1,11 +1,8 @@
 const fetch = require('node-fetch'),
-	fs = require('fs'),
-	log = require('./logging');
+	jsonFetchMocks = require('./jsonFetchMocks');
 
 module.exports = (function() {
 	const DEFAULT_TIMEOUT = 20000;
-	let useMocks = false,
-		mocks;
 
 	const handleHttpErrors = response => {
 		if (response.status !== 200) {
@@ -15,68 +12,26 @@ module.exports = (function() {
 		}
 	};
 
-	const mocksFile = process.argv.filter(arg => arg.startsWith('mocks=')).map(arg => arg.substr(6))[0];
-	if (mocksFile) {
-
-		// Force logging on, since this might be important, mocks are only used during development anyway
-		const loggingWasEnabled = log.isEnabled();
-		log.setEnabled(true);
-
-		try {
-			mocks = JSON.parse(fs.readFileSync(mocksFile, 'utf8'));
-			useMocks = true;
-			log.info('[ ] Loaded mocks file "' + mocksFile + '", MOCKS ARE ENABLED.');
-		} catch (e) {
-			log.error('[ ] Mocks file "' + mocksFile + '" not found, MOCKS ARE DISABLED.');
-		}
-
-		// Set logging to original state
-		log.setEnabled(loggingWasEnabled);
-	}
-
 	function getJson(url, headers = {}) {
-		if (useMocks) {
-			const mockResponseFile = mocks[url];
-			if (mockResponseFile) {
-				if (mockResponseFile === 'ENOTFOUND') {
-					return new Promise(function(resolve, reject) {
-						reject({
-							message: 'request failed because of mock ENOTFOUND',
-							code: 'ENOTFOUND',
-							name: 'FetchError'
-						})
-					});
-				}
-
-				try {
-					const mockResponse = JSON.parse(fs.readFileSync(mockResponseFile, 'utf8'));
-					log.info('[ ] Mock "' + mockResponseFile + '" used to simulate response.');
-					return new Promise(function(resolve) {
-						resolve(mockResponse);
-					});
-				} catch (e) {
-					log.error('[ ] Mock "' + mockResponseFile + '" not found. Check your mocks file!');
-				}
-			}
-		}
-
-		return fetch(url, {
+		return jsonFetchMocks.getMock(url, 'GET') || fetch(url, {
 			'headers': headers,
 			'timeout': DEFAULT_TIMEOUT
 		})
 			.then(handleHttpErrors)
-			.then(response => response.json());
+			.then(response => response.json())
+			.then(jsonFetchMocks.generateMocks(url, 'GET'));
 	}
 
 	function postJson(url, body, headers = {}) {
-		return fetch(url, {
+		return jsonFetchMocks.getMock(url, 'POST') || fetch(url, {
 			'headers': headers,
 			'timeout': DEFAULT_TIMEOUT,
 			'body': body,
 			'method': 'POST'
 		})
 			.then(handleHttpErrors)
-			.then((response) => response.json());
+			.then((response) => response.json())
+			.then(jsonFetchMocks.generateMocks(url, 'POST'));
 	}
 
 	return {

diff --git a/modules/jsonFetchMocks.js b/modules/jsonFetchMocks.js
@@ -0,0 +1,121 @@
+const fs = require('fs'),
+	log = require('./logging'),
+	path = require('path');
+
+module.exports = (function() {
+	let useMocks = false,
+		mocks,
+		generateMocks = false,
+		mocksDirName;
+
+	const mocksFile = process.argv.filter(arg => arg.startsWith('mocks=')).map(arg => arg.substr(6))[0];
+	const generateMocksFile = process.argv.filter(arg => arg.startsWith('generate-mocks=')).map(arg => arg.substr(15))[0];
+	const reportUnmockedCalls = process.argv.filter(arg => arg.startsWith('report-unmocked=')).map(arg => arg.substr(16)).map(arg => arg === 'true')[0];
+
+	const writeObjectToFile = (file, contents) => {
+		fs.writeFile(file, JSON.stringify(contents), function(err) {
+			if (err) throw err;
+		});
+	};
+
+	const saveMocks = () => {
+		writeObjectToFile(generateMocksFile, mocks);
+	};
+
+	if (mocksFile) {
+		// Force logging on, since this might be important, mocks are only used during development anyway
+		const loggingWasEnabled = log.isEnabled();
+		log.setEnabled(true);
+
+		try {
+			mocks = JSON.parse(fs.readFileSync(mocksFile, 'utf8'));
+			useMocks = true;
+			log.info('[ ] Loaded mocks file "' + mocksFile + '", MOCKS ARE ENABLED.');
+		} catch (e) {
+			log.error('[ ] Mocks file "' + mocksFile + '" not found, MOCKS ARE DISABLED.');
+		}
+
+		// Set logging to original state
+		log.setEnabled(loggingWasEnabled);
+	} else if (generateMocksFile) {
+		// Force logging on, since this might be important, mocks are only used during development anyway
+		const loggingWasEnabled = log.isEnabled();
+		log.setEnabled(true);
+
+		try {
+			if (fs.existsSync(generateMocksFile)) {
+				mocks = JSON.parse(fs.readFileSync(generateMocksFile, 'utf8'));
+				log.info('[ ] Mock generation enabled to file "' + generateMocksFile + '", WARNING, EXISTING FILE WILL BE ALTERED.');
+			} else {
+				mocks = {};
+				saveMocks();
+				log.info('[ ] Mock generation enabled to file "' + generateMocksFile + '".');
+			}
+			useMocks = true;
+			mocksDirName = path.dirname(generateMocksFile);
+			generateMocks = true;
+		} catch (e) {
+			log.error('[ ] Error while accessing mock generation file "' + generateMocksFile + '" MOCK GENERATION IS DISABLED.');
+			generateMocks = false;
+		}
+
+		// Set logging to original state
+		log.setEnabled(loggingWasEnabled);
+	}
+
+	const generateMocksFunction = (url, method) => response => {
+		if (generateMocks) {
+			try {
+				const existingMock = mocks[method + '|' + url];
+				const mockFileName = `${mocksDirName}/${url.replace(/http:\/\/|https:\/\//g, '').replace(/\.|\/|\?/g, '_')}.json`;
+				if (existingMock) {
+					log.info('[ ] Mock already exists:', url, mockFileName);
+				} else {
+					log.info('[X] Recording mock:', url, mockFileName);
+					mocks[method + '|' + url] = mockFileName;
+					writeObjectToFile(mockFileName, response);
+					saveMocks();
+				}
+			} catch (err) {
+				log.error('[ ] Error while writing mock file,', err);
+			}
+		}
+		return response;
+	};
+
+	const getMock = (url, method) => {
+		if (useMocks) {
+			const mockResponseFile = mocks[method + '|'+ url];
+			if (mockResponseFile) {
+				if (mockResponseFile === 'ENOTFOUND') {
+					return new Promise(function(resolve, reject) {
+						reject({
+							message: 'request failed because of mock ENOTFOUND',
+							code: 'ENOTFOUND',
+							name: 'FetchError'
+						})
+					});
+				}
+
+				try {
+					const mockResponse = JSON.parse(fs.readFileSync(mockResponseFile, 'utf8'));
+					log.info('[ ] Mock "' + mockResponseFile + '" used to simulate response.');
+					return new Promise(function(resolve) {
+						resolve(mockResponse);
+					});
+				} catch (e) {
+					log.error('[ ] Mock "' + mockResponseFile + '" not found. Check your mocks file!');
+				}
+			}
+
+			if (reportUnmockedCalls) {
+				log.info('[X] NO MOCK FOUND for url:', url);
+			}
+		}
+	};
+
+	return {
+		'getMock': getMock,
+		'generateMocks': generateMocksFunction
+	};
+}());
diff --git a/package.json b/package.json
@@ -1,6 +1,6 @@
 {
 	"name": "express-api-tools",
-	"version": "1.0.5",
+	"version": "1.0.6",
 	"description": "Pragmatic tools to build JSON api endpoints.",
 	"main": "index.js",
 	"author": {
@@ -32,4 +32,4 @@
 		"api",
 		"tools"
 	]
-}
+}
diff --git a/readme.md b/readme.md
@@ -125,7 +125,8 @@ jsonFetch.getJson('https://www.google.com', headers).then(body => {
 
 > A simple post variant is also available.
 
-> Mocks can be enabled by starting the server using a command line argument mocks=./someMocksFile.json. The mocks file
+#### Mocks
+Mocks can be enabled by starting the server using a command line argument: ```mocks=./someMocksFile.json```. The mocks file
 contains a simple json object with key/values. The key is the exact url that is fetched by jsonFetch, the value is
 a reference to another json file which contains the response that should be returned. If the value is 'ENOTFOUND',
 a not found error will be simulated.
@@ -134,9 +135,18 @@ a not found error will be simulated.
 	"https://www.google.com": "./mocks/google_mock.json",
 	"https://www.bing.com": "ENOTFOUND"
 }
-
 ```
 
+It is possible to enable logging of all calls that are not mocked while mocks are enabled. This can be used to trace
+unmocked calls, if needed. This can be done by adding the command line argument: ```report-unmocked=true```.
+
+#### Mock recording
+Mocks can also automatically be recorded (to take a snapshot of a specific moment). Add the following command line argument:
+```generate-mocks=./some/path/someMocksFile.json```. The mocks file will be appended if it already exists. Otherwise,
+it will be created and all recorded mocks will be automatically added. The actual responses will be recorded in separate
+json files that will be saved in the same directory as the specified mocks file. If a response is recorded once, subsequent
+calls to the same endpoint will return the mocked response.
+
 ## Api endpoints
 This package also contains a few example api endpoints that can be used in production.