Web Service Clients On Raspberry Pi Pico W(C++)

Restful Web Services for the Raspberry Pi Pico W

What you'll learn

Understand Restful Web Services Concepts

Write Web Service clients on the Raspberry Pi Pico using LWIP

Write Web Service clients on the Raspberry Pi Pico using coreHTTP

Write Web Service servers on the Raspberry Pi Pico using LWIP

Write Web Service servers on the Raspberry Pi Pico using Socket based HTTPD

Requirements

Able to work with the Raspberry Pi Pico SDK Toolchain

Able to programme in C/C++ on microcontroller

Awareness of computer networks (IP and Ethernet)

Able to install software and configure firewall on own laptop or desktop

Basic knowledge of Python which will be used for test clients and servers.

Description

Using Web Services I can pull real-world data for my Raspberry PI Pico W to act on. Or submit sensor data from my Pico W to central services in an IoT pattern. Web Services enable us to connect the Pico W to a wider world of exciting distributed systems.In this course, we explore how to code C/C++ for a Pico-W to become a web service client. We look at two fundamental libraries to manage the HTTP protocol; LWIP HTTP App and coreHTTP. coreHTTP requires that we also use FreeRTOS kernel and LWIP Sockets. The library gives us a great deal of flexibility and with wolfSSL allows us to connect to HTTPS web services.The restful web services we primarily target on the course respond with JSON payloads. The course teaches how to parse these using two optional libraries coreJSON and tiny-JSON. Some web service payloads return XML and a further two libraries are explored to be able to handle these payloads.The course uses STDIO for the output of most web services. Two examples use a pre-built Pico-W display board, the PIMORONI Galactic Unicorn. One example uses a TFT screen, this will needs to be wired to the Pico W. Optionally you could modify these examples to produce STDIO or use alternative hardware.The course assumes knowledge of C++. Though each example walks through the functionality, the course will not talk about the syntax of C++. FreeRTOS Kernel is used to support concurrent tasks and enable POSIX Sockets. An understanding of FreeRTOS Kernel is assumed. I have another course on FreeRTOS Kernel for the Raspberry PI Pico to cover this.The course assumes you can compile and deploy C++ code to the Pico Q using the Raspberry PI Pico SDK. My other course “Introduction to C Development Environment for Raspberry PICO” teaches these skills.A web service test environment to support building and understanding these web services clients uses Python. Some Python knowledge would be helpful.

Overview

Section 1: Introduction

Lecture 1 Introduction

Lecture 2 Introducing Your Tutor

Lecture 3 Course Approach

Lecture 4 Section Summary

Section 2: First Service Client

Lecture 5 Section Goals

Lecture 6 Pico W Setup

Lecture 7 Code Deployment or Flashing

Lecture 8 Course Code Repository Structure

Lecture 9 Connecting to Wifi

Lecture 10 IP Geolocation Service

Lecture 11 First Pico-W Client

Lecture 12 Section Summary

Section 3: Web Services Origin and test Environment

Lecture 13 Section Goals

Lecture 14 Origin of Web Services

Lecture 15 Web Service Standards and RESTful Web Services

Lecture 16 Test Environment: Python

Lecture 17 First Web Service

Lecture 18 Parameters over GET Web Service

Lecture 19 Web Service based on HTTP POST

Lecture 20 Authentication for a Web Service

Lecture 21 Debugging Web Services: Proxy Server

Lecture 22 Section Summary

Section 4: URI and URL

Lecture 23 Section Goals

Lecture 24 What is an URI and an URL.

Lecture 25 URI Library to Parse a URL

Lecture 26 URI Parser Library to Parse a URL

Lecture 27 Section Summary

Section 5: LwIP HTTP Client

Lecture 28 Section Goals

Lecture 29 LwIP Library

Lecture 30 LwIP HTTP Client

Lecture 31 Request Query

Lecture 32 Debugging LwIP HTTP

Lecture 33 LwIP HTTP Client Limitations

Lecture 34 Section Summary

Section 6: JSON

Lecture 35 Section Goals

Lecture 36 Introducing JSON

Lecture 37 TinJSON Library

Lecture 38 CoreJSON Library

Lecture 39 Section Summary

Section 7: FreeRTOS coreHTTP

Lecture 40 Section Goals

Lecture 41 FreeRTOS Kernel and LwIP

Lecture 42 POSIX Sockets

Lecture 43 HTTP GET

Lecture 44 HTTP POST

Lecture 45 Section Summary

Section 8: HTTP Security

Lecture 46 Section Goals

Lecture 47 HTTP Basic Authentication

Lecture 48 TLS Transport

Lecture 49 TLS HTTP Request Client

Lecture 50 TLS Identity

Lecture 51 Section Summary

Section 9: Parsing XML Payloads

Lecture 52 Section Goals

Lecture 53 XML the Basics

Lecture 54 MXML Library

Lecture 55 MiniML Library

Lecture 56 Section Summary

Section 10: Congratulations and Examples

Lecture 57 Congratulations and Optional Goals

Lecture 58 Course Recap

Lecture 59 Debugging Web Services

Lecture 60 YouTube Subscription Ticker

Lecture 61 Weather Forecast

Lecture 62 Currency Rates Ticker

Lecture 63 Thank You

IoT developers,Hobbyist working on IoT and Web Service projects,Embedded developers