close #22 by adding preliminary etag support

lib/response.js

@@ -7,10 +7,6 @@
  */
 
 const UTILS = require('./utils.js')
-// const escapeHtml = require('./utils.js').escapeHtml
-// const encodeUrl = require('./utils.js').encodeUrl
-// const encodeBody = require('./utils.js').encodeBody
-// const mimeLookup = require('./utils.js').mimeLookup
 
 const fs = require('fs') // Require Node.js file system
 const path = require('path') // Require Node.js path
@@ -37,6 +33,9 @@ class RESPONSE {
 
     // Default callback function
     this._callback = 'callback'
+
+    // Default Etag support
+    this._etag = false
   }
 
   // Sets the statusCode
@@ -352,10 +351,35 @@ class RESPONSE {
   }
 
 
+  // Enable/Disable Etag
+  etag(enable) {
+    this._etag = enable === true ? true : false
+    return this
+  }
+
 
   // Sends the request to the main callback
   send(body) {
 
+    // Generate Etag
+    if ( this._etag // if etag support enabled
+      && this.app.request // if request exists
+      && ['GET','HEAD'].includes(this.app.request.method)
+      && !this.hasHeader('etag')
+      && this._statusCode === 200
+    ) {
+      this.header('etag','"'+UTILS.generateEtag(body)+'"')
+    }
+
+    // Check for matching Etag
+    if ( this.app.request
+      && this.app.request.headers['if-none-match']
+      && this.app.request.headers['if-none-match'] === this.getHeader('etag')
+    ) {
+      this.status(304)
+      body = ''
+    }
+
     // Create the response
     const response = {
       headers: this._headers,
@@ -370,7 +394,6 @@ class RESPONSE {
   } // end send
 
 
-
   // Trigger API error
   error(e) {
     this.app.catchErrors(e)

lib/utils.js

@@ -7,6 +7,7 @@
  */
 
  const QS = require('querystring') // Require the querystring library
+ const crypto = require('crypto') // Require Node.js crypto library
 
  const entityMap = {
    "&": "&",
@@ -30,9 +31,11 @@ module.exports.encodeUrl = url => String(url)
 
 
 
-module.exports.encodeBody = body =>
+const encodeBody = body =>
   typeof body === 'object' ? JSON.stringify(body) : (body && typeof body !== 'string' ? body.toString() : (body ? body : ''))
 
+module.exports.encodeBody = encodeBody
+
 
 
 module.exports.parseBody = body => {
@@ -98,3 +101,8 @@ const extractRoutes = (routes,table=[]) => {
 }
 
 module.exports.extractRoutes = extractRoutes
+
+
+// Generate an Etag for the supplied value
+module.exports.generateEtag = data =>
+  crypto.createHash('sha256').update(encodeBody(data)).digest("hex").substr(0,32)

test/etag.js

@@ -0,0 +1,86 @@
+'use strict';
+
+const expect = require('chai').expect // Assertion library
+
+// Init API instance
+const api = require('../index')({ version: 'v1.0' })
+
+// NOTE: Set test to true
+api._test = true;
+
+let event = {
+  httpMethod: 'get',
+  path: '/test',
+  body: {},
+  headers: {
+    'Content-Type': 'application/json'
+  }
+}
+
+/******************************************************************************/
+/***  DEFINE TEST ROUTES                                                    ***/
+/******************************************************************************/
+
+api.get('/testEtag', function(req,res) {
+  res.etag(true).send({ test: true })
+})
+
+api.get('/testEtag2', function(req,res) {
+  res.etag(true).send({ test: false })
+})
+
+/******************************************************************************/
+/***  BEGIN TESTS                                                           ***/
+/******************************************************************************/
+
+describe('Etag Tests:', function() {
+
+  it('Initial request', async function() {
+    let _event = Object.assign({},event,{ path: '/testEtag'})
+    let result = await new Promise(r => api.run(_event,{},(e,res) => { r(res) }))
+    expect(result).to.deep.equal({ headers: {
+      'content-type': 'application/json',
+      'etag': '"6fd977db9b2afe87a9ceee4843288129"'
+    }, statusCode: 200, body: '{"test":true}', isBase64Encoded: false })
+  }) // end it
+
+  it('Initial request 2', async function() {
+    let _event = Object.assign({},event,{ path: '/testEtag2'})
+    let result = await new Promise(r => api.run(_event,{},(e,res) => { r(res) }))
+    expect(result).to.deep.equal({ headers: {
+      'content-type': 'application/json',
+      'etag': '"ad2ba8d138b3cda185243603ec9fcaa7"'
+    }, statusCode: 200, body: '{"test":false}', isBase64Encoded: false })
+  }) // end it
+
+  it('Second request', async function() {
+    let _event = Object.assign({},event,{ path: '/testEtag', headers: { 'If-None-Match': '"6fd977db9b2afe87a9ceee4843288129"' }})
+    let result = await new Promise(r => api.run(_event,{},(e,res) => { r(res) }))
+    expect(result).to.deep.equal({ headers: {
+      'content-type': 'application/json',
+      'etag': '"6fd977db9b2afe87a9ceee4843288129"'
+    }, statusCode: 304, body: '', isBase64Encoded: false })
+  }) // end it
+
+  it('Second request 2', async function() {
+    let _event = Object.assign({},event,{ path: '/testEtag2', headers: { 'If-None-Match': '"ad2ba8d138b3cda185243603ec9fcaa7"' }})
+    let result = await new Promise(r => api.run(_event,{},(e,res) => { r(res) }))
+    expect(result).to.deep.equal({ headers: {
+      'content-type': 'application/json',
+      'etag': '"ad2ba8d138b3cda185243603ec9fcaa7"'
+    }, statusCode: 304, body: '', isBase64Encoded: false })
+  }) // end it
+
+  it('Non-matching Etags', async function() {
+    let _event = Object.assign({},event,{ path: '/testEtag', headers: { 'If-None-Match': '"ad2ba8d138b3cda185243603ec9fcaa7"' }})
+    let result = await new Promise(r => api.run(_event,{},(e,res) => { r(res) }))
+    expect(result).to.deep.equal({ headers: {
+      'content-type': 'application/json',
+      'etag': '"6fd977db9b2afe87a9ceee4843288129"'
+    }, statusCode: 200, body: '{"test":true}', isBase64Encoded: false })
+  }) // end it
+
+
+
+
+}) // end ERROR HANDLING tests

test/utils.js

@@ -258,4 +258,36 @@ describe('Utility Function Tests:', function() {
 
   }) // end extractRoutes
 
+
+  describe('generateEtag:', function() {
+
+    it('Sample text', function() {
+      expect(utils.generateEtag('this is a test string')).to.equal('f6774519d1c7a3389ef327e9c04766b9')
+    }) // end it
+
+    it('Sample object', function() {
+      expect(utils.generateEtag({ test: true, foo: 'bar' })).to.equal('def7648849c1e7f30c9a9c0ac79e4e52')
+    }) // end it
+
+    it('Sample JSON string object', function() {
+      expect(utils.generateEtag(JSON.stringify({ test: true, foo: 'bar' }))).to.equal('def7648849c1e7f30c9a9c0ac79e4e52')
+    }) // end it
+
+    it('Sample buffer', function() {
+      expect(utils.generateEtag(Buffer.from('this is a test string as a buffer'))).to.equal('6a2f7473a72cfebc96ae8cf93d643b70')
+    }) // end it
+
+    it('Long string', function() {
+      let longString = 'Lorem ipsum dolor sit amet, consectetur adipiscing elit, sed do eiusmod tempor incididunt ut labore et dolore magna aliqua. Ut enim ad minim veniam, quis nostrud exercitation ullamco laboris nisi ut aliquip ex ea commodo consequat. Duis aute irure dolor in reprehenderit in voluptate velit esse cillum dolore eu fugiat nulla pariatur. Excepteur sint occaecat cupidatat non proident, sunt in culpa qui officia deserunt mollit anim id est laborum.'
+      expect(utils.generateEtag(longString)).to.equal('2d8c2f6d978ca21712b5f6de36c9d31f')
+    }) // end it
+
+    it('Long string (minor variant)', function() {
+      let longString = 'Lorem ipsum dolor sit amet, consectetur adipiscing elit, sed do eiusmod tempor incididunt ut labore et dolore magna aliqua. Ut enim ad minim veniam, quis nostrud exercitation ullamco laboris nisi ut aliquip ex ea commodo consequat. Duis aute irure dolor in reprehenderit in voluptate velit esse cillum dolore eu fugiat nulla pariatur. Excepteur sint occaecat cupidatat non proident, sunt in culpa qui officia deserunt mollit anim id est Laborum.'
+      expect(utils.generateEtag(longString)).to.equal('bc82a4065a8ab48ade900c6466b19ccd')
+    }) // end it
+
+  }) // end generateEtag tests
+
+
 }) // end UTILITY tests