miso419 / api-helper

API Helper

Helpers that are commonly used in microservices.

Setup

npm install api-helper --save

Table of contents

• AuditLog
• cacheHelper
• responseHelper
• requestHelper

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AuditLog

It helps to extract changes from old and new JSON objects and log them via the Audit Service. Currently supports user level actions only.

Simple usages

First, create new AuditLog instance with the Audit Service endpoint (Using config is recommended instead of hard-coding). For single table, you can simply call createUserLogForCreate, createUserLogForUpdate or createUserLogForDelete accordingly.

• requestId: (string) Request ID from the caller
• userId: (integer) User ID who requires the action
• tableName: (string) DB table name to be affected
• recordId: (integer) DB table record ID to be affected
• oldObject: (object) Old object before changes
• newObject: (object) New object after changes

import { AuditLog } from 'api-helper';
const auditLog = new AuditLog('https://dev.audit-service.com.au', 'project name');

function createSubdomain(requestId, userId, organisationId, subdomain) {
    return userManager.getUser(userId)
        .then(user => validateSubdomain(subdomain))
        .then(() => Organisation.update({ code: subdomain }, { where: { id: organisationId } }))
        .then(() => auditLog.createUserLogForUpdate(requestId, userId, 'Organisation', organisationId, {}, { code: subdomain }));
}

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cacheHelper

It helps to use Redis cache.

Usages

1. setup

Create a Redis connection. It must be called in server.js to initialise cacheHelper.

import config from 'config';
import Server from 'microservice-base';
import { cacheHelper } from 'api-helper';
import routes from './routes';

cacheHelper.setup(config.redis.endpoint);

export default function() {
    const server = new Server({
        name: 'ACCOUNT-SERVICE',
        localPort: 4002,    //DO NOT CHANGE. USED BY OTHER SERVICES FOR LOCAL TESTS.
        logConfig: { ...config.cloudWatch },
        docs: './docs/api.raml',
        routes: routes
    });

    server.start();
    return server;
}

2. set

Set cache with a key and a JSON object. Use third parameter expiryIn to set expiry time - Availble time indicators are 'd' for days, 'h' for hours, and 'm' for minutes. (eg. 3d, 2h, 30m) If expiryIn is not provided, no expiry time will be set.

import { responseHelper, cacheHelper } from 'api-helper';
import db from '../models';
import constants from '../helpers/constants';

const { Activity } = db.models;
const { cacheKeys, classificationStatuses, classificationStatusesAll } = constants;

function getAllActivities() {
    const cacheKey = cacheKeys.primaryActivityAll;
    return cacheHelper.get(cacheKey)
        .then(cacheResult => {
            if (cacheResult) {
                return Promise.resolve(cacheResult);
            }

            return Activity.findAll()
                .then(result => {
                    cacheHelper.set(cacheKey, result, '6h');    //Expired in 6h
                    return Promise.resolve(result);
                });
        });
}

3. get

Get a cached object by key.

import { responseHelper, cacheHelper } from 'api-helper';
import db from '../models';
import constants from '../helpers/constants';

const { Activity } = db.models;
const { cacheKeys, classificationStatuses, classificationStatusesAll } = constants;

function getAllActivities() {
    const cacheKey = cacheKeys.primaryActivityAll;
    return cacheHelper.get(cacheKey)
        .then(cacheResult => {
            if (cacheResult) {
                return Promise.resolve(cacheResult);
            }

            return Activity.findAll()
                .then(result => {
                    cacheHelper.set(cacheKey, result, '6h');    //Expired in 6h
                    return Promise.resolve(result);
                });
        });
}

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responseHelper

It helps to create a JSON response object for any API requests.

Usages

1. createError

Creates single error object with a error code, error message, and error field. Note that it returns a string to be used as the message parameter in an error class.

import { responseHelper } from 'api-helper';

function validateEmail(email) {
    if (!email) {
        throw new SyntaxError(responseHelper.createError(responseHelper.errorCodes.field_validation_error, 'Email is required', 'email'));
    }
}

2. createErrors

Creates an error list. Note that it returns a string to be used as the message parameter in an error class.

import { responseHelper } from 'api-helper';

function validateEmail(email) {
    const errors = [
        { 
            errorCode: responseHelper.errorCodes.field_validation_error,
            errorMessage: 'Email is required',
            errorField: 'email'
        },
        { 
            errorCode: responseHelper.errorCodes.unique_key_error,
            errorMessage: 'Email is already registered',
            errorField: 'email'
        }
    ]
    
    throw new SyntaxError(responseHelper.createErrors(errors));
}

3. createData

Creates response data object that has no error. Note that it returns a JSON object.

import { responseHelper } from 'api-helper';

function getData() {
    const testData = {
        id: 1,
        name: 'John',
        company: 'MyCom'
    };
    
    return responseHelper.createData(testData);
}

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requestHelper

Comming soon.

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