Code files

Chapter05/receiving-post-data/accepting-json/package.json

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+{
+  "name": "accepting-json",
+  "version": "1.0.0",
+  "description": "",
+  "main": "server.js",
+  "scripts": {
+    "test": "echo \"Error: no test specified\" && exit 1",
+    "start": "node server.js"
+  },
+  "keywords": [],
+  "author": "David Mark Clements",
+  "license": "MIT",
+  "dependencies": {
+    "fast-json-parse": "^1.0.2"
+  }
+}

Chapter05/receiving-post-data/accepting-json/public/form.html

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+<form method="post">
+  <input type="text" name="userinput1"><br>
+  <input type="text" name="userinput2"><br>
+  <input type="submit">
+</form>
+<script>
+  document.forms[0].addEventListener('submit', function (evt) {
+    evt.preventDefault()
+    var form = this
+    var data = Object.keys(form).reduce(function (o, i) {
+      if (form[i].name) o[form[i].name] = form[i].value
+      return o
+    }, {})
+    form.innerHTML = ''
+    var xhr = new XMLHttpRequest()
+    xhr.open('POST', '/')
+    xhr.setRequestHeader('Content-Type', 'application/json')
+    xhr.send(JSON.stringify(data))
+    xhr.addEventListener('load', function () {
+      var res
+      try { res = JSON.parse(this.response) } catch (e) {
+        res = {error: 'Mangled Response'}
+      }
+      form.innerHTML = res.error 
+        ? res.error 
+        : 'You Posted: ' + JSON.stringify(res.data)
+    })
+  })
+</script>

Chapter05/receiving-post-data/accepting-json/server.js

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+'use strict'
+
+const http = require('http')
+const fs = require('fs')
+const path = require('path')
+const parse = require('fast-json-parse')
+const form = fs.readFileSync(path.join(__dirname, 'public', 'form.html'))
+const maxData = 2 * 1024 * 1024 // 2mb
+
+http.createServer((req, res) => {
+  if (req.method === 'GET') {
+    get(res)
+    return
+  }
+  if (req.method === 'POST') {
+    post(req, res)
+    return
+  }
+  reject(405, 'Method Not Allowed', res)
+}).listen(8080)
+
+function get (res) {
+  res.writeHead(200, {'Content-Type': 'text/html'})
+  res.end(form)  
+}
+
+function post (req, res) {
+  if (req.headers['content-type'] !== 'application/json') {
+    reject(415, 'Unsupported Media Type', res)
+    return
+  }
+  const size = parseInt(req.headers['content-length'], 10)
+  if (isNaN(size)) {
+    reject(400, 'Bad Request', res)
+    return
+  }
+  if (size > maxData) {
+    reject(413, 'Too Large', res)
+    return
+  }
+  const buffer = Buffer.allocUnsafe(size)
+  var pos = 0
+
+  req
+    .on('data', (chunk) => {
+      const offset = pos + chunk.length
+      if (offset > size) {
+        reject(413, 'Too Large', res)
+        return
+      }
+      chunk.copy(buffer, pos)
+      pos = offset
+    })
+    .on('end', () => {
+      if (pos !== size) {
+        reject(400, 'Bad Request', res)
+        return
+      }
+      const data = buffer.toString()
+      const parsed = parse(data)
+      if (parsed.err) {
+        reject(400, 'Bad Request', res)
+        return  
+      }
+      console.log('User Posted: ', parsed.value)
+      res.end('{"data": ' + data + "}")
+    })
+}
+
+function reject (code, msg, res) {
+  res.statusCode = code
+  res.end(msg)
+}