List of Listings

Chapter 2. Hello, World Wide Web of Things

Listing 2.1. Polling for the temperature sensor

Listing 2.2. Polling and displaying a sensor reading

Listing 2.3. Connecting to a WebSocket and listening for messages

Listing 2.4. Register to a WebSocket and get real-time temperature updates

Listing 2.5. Simple HTML form to send a command to an actuator

Listing 2.6. Send an HTTP POST with JSON payload from a form

Listing 2.7. A basic device browser

Listing 2.8. Retrieve and parse device metadata using AJAX JSON calls

Listing 2.9. Mashup function

Chapter 3. Node.js for the Web of Things

Listing 3.1. A Hello World HTTP server in Node.js

Listing 3.2. A simple HTTP server returning JSON data

Listing 3.3. A simple package.json file

Listing 3.4. operations.js: a mathematics module in Node.js

Listing 3.5. A simple Node application using the operations module

Listing 3.6. An asynchronous call to the database

Listing 3.7. Using the request library

Listing 3.8. A mashup with asynchronous calls leading to a “callback hell”

Listing 3.9. A mashup with asynchronous calls and named callbacks

Listing 3.10. Using async.series for serial control flow

Listing 3.11. Using a control flow library

Chapter 4. Getting started with embedded systems

Listing 4.1. Modifying the Wi-Fi configuration file

Listing 4.2. Pinging your Pi

Listing 4.3. Connecting to the Pi using ssh

Listing 4.4. Installing Node.js on your Pi

Listing 4.5. Configuring GitHub on the Pi and forking the project

Listing 4.6. blink.js: the Hello World of the IoT

Listing 4.7. pir.js: reading a PIR sensor using the onoff library

Listing 4.8. Installing the BCM2835 driver

Listing 4.9. dht.js: communicating with the DHT22 sensor

Chapter 5. Building networks of Things

Listing 5.1. Enabling IPv6 support on your Raspberry Pi

Listing 5.2. Testing Bluetooth 4.0: BLE on a Raspberry Pi

Chapter 6. Access: Web APIs for Things

Listing 6.1. A simple HTTP request and response

Listing 6.2. Requesting an XML return payload using the Accept header

Listing 6.3. Requesting a JSON return payload using the Accept header

Listing 6.4. GET to read a resource (the temperature sensor of our Pi)

Listing 6.5. POST to create a new resource

Listing 6.6. PUT to update an existing resource (change the colors of the LEDs)

Listing 6.7. DELETE to remove an existing resource

Listing 6.8. GET request to a resource using CORS

Listing 6.9. HTML representation of the Raspberry Pi root resource

Listing 6.10. JSON representation of the “links” resource of a Raspberry Pi

Listing 6.11. Using OPTIONS to retrieve the verbs supported by a resource

Listing 6.12. Subscription via a webhook

Listing 6.13. Client request in a WebSockets handshake

Listing 6.14. Server response in a WebSockets handshake

Chapter 7. Implementing web Things

Listing 7.1. WoT server for Pi project directory structure

Listing 7.2. /resources/resources.json: JSON model of the Pi resources

Listing 7.3. /routes/sensors.js: routes for sensors

Listing 7.4. /servers/http.js: Express application

Listing 7.5. /wot-server.js: application entry point

Listing 7.6. /plugins/internal/pirPlugin.js: PIR sensor plugin

Listing 7.7. /plugins/internal/DHT22SensorPlugin.js: temperature and humidity sensor plugin

Listing 7.8. Integrating the plugins to wot-server.js

Listing 7.9. /middleware/converter.js: implementing representation middleware

Listing 7.10. Calling the next middleware in sensors.js

Listing 7.11. Adding PUT support for LEDs in /routes/actuators.js

Listing 7.12. /plugins/internal/ledsPlugin.js: LED plugin

Listing 7.13. /server/websockets.js: WebSockets server

Listing 7.14. Enabling the WebSockets server in wot-server.js

Listing 7.15. coap.js: a simple CoAP server

Listing 7.16. /plugins/external/coapPlugin.js: a simple CoAP plugin

Listing 7.17. simple-plug.js: simulated power plug that connects to EVRYTHNG via MQTT

Listing 7.18. plug-with-control.js: subscribe and handle actions pushed from the server

Listing 7.19. client/plug.html: attach a handler to the toggle button

Listing 7.20. client/plugs.html: the sendAction() function

Listing 7.21. Connecting to WebSockets and handling property updates

Chapter 8. Find: Describe and discover web Things

Listing 8.1. An mDNS message from a printer

Listing 8.2. Pseudocode for crawling the HTML representation of Things

Listing 8.3. GET {WT}: retrieve the metadata of a web Thing

Listing 8.4. GET {WT}/properties: retrieve the properties of a web Thing

Listing 8.5. Retrieve the temperature property

Listing 8.6. GET {WT}/actions: retrieve the actions supported by a web Thing

Listing 8.7. GET {WT}/model: the actions object of a web Thing model

Listing 8.8. POST {WT}/actions/ledState: turn on LED 3

Listing 8.9. GET {WT}/things: the things object of the Web Thing Model

Listing 8.10. Temperature property for Pi

Listing 8.11. /routes/routesCreator.js: root resource route

Listing 8.12. /routes/routesCreator.js: actions resources routes

Listing 8.13. /plugins/corePlugin.js: generic plugin for common features

Listing 8.14. /plugins/ledsPlugin.js: LED plugin working with the Web Thing Model

Listing 8.15. The HTML representation of the root resource with RDFa annotations

Listing 8.16. Templating HTML view in Express with RDFa tags

Listing 8.17. /middleware/converter.js: extending the converter

Listing 8.18. resources/piJsonLd.json: adding JSON-LD to our JSON model

Listing 8.19. middleware/converter.js: adding support for JSON-LD representations

Chapter 9. Share: Securing and sharing web Things

Listing 9.1. Information requested when generating a self-signed certificate

Listing 9.2. Modifying the WoT Pi server to serve HTTPS and WSS content

Listing 9.3. utils/utils.js: generate a crypto-secure API token

Listing 9.4. auth.js: authentication middleware

Listing 9.5. providers/facebook.js: a Facebook authentication strategy

Listing 9.6. config/acl.json: the access control list JSON file

Listing 9.7. Authorizing user requests: /middleware/auth.js

Listing 9.8. Proxying requests to Things: /middleware/proxy.js

Chapter 10. Compose: Physical mashups

Listing 10.1. Retrieve the JSON model of a web Thing with jQuery

Listing 10.2. The actions object of the Web Thing Model for our Pi

Listing 10.3. The HTML code of the form to create an ledState action

Listing 10.4. The generateActions() function

Listing 10.5. The PIR and LED properties of the Pi Web Thing Model

Listing 10.6. The generateProperties() function

Listing 10.7. Prepare LED message function node