AI-Assisted Coding: The Practical Guide for Software Development

Notes on Usage....5 Table of Contents....7 Preface....22 Local Execution of Language Models....22 Coding with AI Support for Advanced Users....23 AI Makes Mistakes and Hallucinates....25 The Three Stages of Using AI....26 There’s No Getting around AI Tools....27 Part I Coding with AI Support....30 1 Introduction....31 1.1 Coding via Chat....31 1.1.1 Password Generator....32 1.1.2 Python: Searching and Replacing Dates....33 1.1.3 SQL: Analysis of a Table....36 1.1.4 PHP: Bearer Token Authentication....38 1.1.5 Porting a Bash Script for PowerShell....40 1.1.6 Paid ChatGPT Offers....42 1.1.7 Anthropic Claude....44 1.2 The Art of Prompting....45 1.2.1 Prompt Frameworks....49 1.2.2 A Question of Context....50 1.2.3 Custom GPTs....53 1.2.4 Comparing Custom GPTs, Fine-Tuning, and Retrieval-Augmented Generation....55 1.3 Code Wizards....57 1.3.1 Installing GitHub Copilot....59 1.3.2 First Steps with Visual Studio Code and GitHub Copilot....60 1.3.3 Switching between Code Suggestions....61 1.3.4 Tips and Tricks....63 1.3.5 Chat Mode with Additional Keywords....64 1.3.6 Chat Examples....66 1.3.7 Alternatives to the Chat Sidebar....69 1.3.8 Other Functions....70 1.3.9 Security and Data Protection....71 1.3.10 Trouble in Remote Mode....72 1.4 Chat or Wizard?....74 1.5 Basic Principles of Large Language Models....76 1.5.1 From the Human Brain to Neural Networks....76 1.5.2 Machine Learning through Backpropagation....78 1.5.3 Large Language Models....79 1.5.4 The Transformer Model....82 1.5.5 Generative Pretrained Transformer (GPT)....84 1.5.6 Training: From Training Material to Language Model....86 1.5.7 Large Language Model Application: From Prompt to Response....88 1.5.8 The Limits of Linguistic “Intelligence”....90 1.5.9 The Size of the Context Window....93 1.5.10 The Fill-in-the-Middle Approach....95 2 Pair Programming....97 2.1 Structuring Code into Functions....99 2.1.1 Defining Functions Yourself....100 2.1.2 Defining Functions and Parameters....101 2.1.3 Detailed Questions about Functions and Parameters....104 2.1.4 Code Optimization....107 2.1.5 Code Reuse....109 2.1.6 Splitting Code across Multiple Files....110 2.2 Example: IBAN Validation....114 2.2.1 Start....114 2.2.2 Checking the IBAN Length....116 2.2.3 Troubleshooting....116 2.2.4 Test....118 2.2.5 Removing Spaces from the IBAN....119 2.2.6 Checksum Test....120 2.2.7 Trouble with the Test Data....122 2.2.8 Code Optimization....122 2.3 Object-Oriented Programming....124 2.3.1 Example: User Account Class....125 2.3.2 Output of the Object....127 2.3.3 JSON Export and Constructor....128 2.3.4 Example: Bank Account....129 2.3.5 Example: Sorting Photos Based on EXIF Data....131 2.3.6 Example: Dealing with Singletons....133 2.4 Example: Quiz....136 2.4.1 Class Design....136 2.4.2 Implementing the Question Class....138 2.4.3 A Pool of Questions for Testing....139 2.4.4 Methods for the Question Class....140 2.4.5 UML Diagram....142 2.4.6 AI Bot or Code Wizard?....143 2.5 Example: Solving Sudoku....145 2.5.1 Class Setup....145 2.5.2 Detaching Individual Fields in Rows....147 2.5.3 Solving Individual Fields in Columns and in Blocks....149 2.5.4 Test Code and Issues with the Test Data....150 2.5.5 Brainstorming....151 2.5.6 Storing Solution Candidates per Field....153 2.5.7 Filling in Fields Where Only One Solution Number Is Possible....154 2.5.8 Personal Conclusion....155 2.5.9 Alternative Procedure....156 2.5.10 Prompting Correctly....158 3 Debugging....159 3.1 Web Applications....161 3.1.1 CSS Fixes....161 3.1.2 iCal Download in the Browser....164 3.1.3 Backend Frontend without a Proxy Server....165 3.1.4 JavaScript Fetch with the Wrong Content Type....168 3.1.5 JamGPT....170 3.2 App Development....173 3.2.1 Flutter and Null Safety Values....173 3.2.2 Layouts in Flutter....175 3.3 Developing on Raspberry Pi....178 3.3.1 Step-by-Step Debugging on a Raspberry Pi....178 3.3.2 Help for Creating Log Entries....180 3.4 Visual Studio and Visual Studio Code....183 3.4.1 Missing Python Modules in VS Code....183 3.4.2 Visual Studio Exception Debugging....184 3.5 Conclusion....187 4 Refactoring....188 4.1 Introduction to Refactoring....189 4.1.1 Objectives of Refactoring....189 4.2 Refactoring Using AI Tools....191 4.2.1 Recognizing the Need for Refactoring....191 4.3 Best Practices....207 4.3.1 Only the Internal Structure May Be Changed....207 4.3.2 Small-Step Approach....207 4.3.3 Test-Driven Refactoring....208 4.3.4 Defining Clear Goals....208 4.4 Conclusion....210 5 Testing Software....212 5.1 Generating Test Data....213 5.2 AI-Supported Test Automation....219 5.2.1 Creating AI-Supported Unit Tests....220 5.3 Test-Driven Development with AI....227 5.3.1 Implementing the First Test....228 5.3.2 The Second Test....230 5.3.3 The Third Test....231 5.3.4 Generating Test Data....233 5.4 Using Dependencies....236 5.5 Optimizing Tests....243 5.5.1 Optimizing Test Code....243 5.5.2 Writing Missing Tests....247 5.6 End-to-End Tests....251 5.6.1 Generating an End-to-End Test....252 5.6.2 Creating a Page Object....254 5.7 Conclusion....257 6 Documenting Software....258 6.1 Challenges with Documentation....260 6.2 Inline Documentation....262 6.2.1 Sample Inline Documentation....263 6.3 Function and Class Documentation....267 6.3.1 Benefits and Drawbacks of Function and Class Documentation....268 6.3.2 Sample Function and Class Documentation....268 6.4 API Documentation....273 6.4.1 Sample API Documentation....273 6.5 Outdated Documentation....277 6.6 Conclusion....281 7 Databases....282 7.1 Database Design....283 7.1.1 Example: Database for an Online Store....283 7.1.2 Database Management System Selection....289 7.1.3 Example: Cloud Shopping List....292 7.1.4 Changing the Database Schema....294 7.2 SQL Commands....299 7.2.1 Date Calculation....299 7.2.2 Troubleshooting....300 7.2.3 WordPress Image Search....302 7.2.4 Complex Query with Subquery or Self Join....304 7.2.5 Formatting an SQL Command....308 7.3 Administration....310 7.3.1 PostgreSQL: User Administration....310 7.3.2 SQL Server: Automated Backup....312 7.3.3 Determining the Schema of a Database....315 7.3.4 MariaDB Tuning....317 7.4 Client Programming....321 8 Scripting and System Administration....323 8.1 Scripting....324 8.1.1 Bash: Loop Over a Text File....324 8.1.2 PowerShell: Sorting Photos....325 8.1.3 Python: SQLite Application....327 8.1.4 Bash Troubleshooting....331 8.1.5 Python: Recursive Search for Files....331 8.1.6 Other Prompt Examples....332 8.2 Example: Converting a Python Script to PHP Code....335 8.2.1 Conclusion....337 8.3 Regular Expressions....339 8.3.1 Searching and Replacing Dates....341 8.3.2 File Search Using grep....342 8.4 System Administration....345 8.4.1 SSH Authentication by Key....345 8.4.2 Docker Setup....347 8.4.3 Proxy Server....349 8.4.4 Fixing Network Issues in a Virtual Machine with a Web Server....351 8.4.5 Linux Server Setup....353 8.4.6 Additional Prompts....354 8.5 Example: “wget” Script Plus “tmpfs” Configuration....356 8.5.1 Developing a “wget” Script....356 8.5.2 Linux Server Configuration with “tmpfs”....360 8.5.3 Conclusion....362 8.6 Calling GitHub Copilot and ChatGPT in the Terminal....364 8.6.1 GitHub Command-Line Interface (“gh”)....364 8.6.2 Shell-GPT (“sgpt”)....365 8.6.3 Using Language Models in the Terminal (“llm”)....367 Part II Local Language Models and Advanced AI Tools....369 9 Executing Language Models Locally....370 9.1 Spoiled for Choice of Large Language Model....371 9.1.1 Which Models Solve Which Problems?....372 9.1.2 Hardware Requirements....375 9.1.3 Alternatives to the Local Execution of Models....378 9.2 GPT4All....380 9.2.1 Installation and Use....381 9.2.2 Chat with Your Files....383 9.2.3 Conclusion....384 9.3 Ollama....385 9.3.1 Benefits of Ollama....385 9.3.2 General Structure of Ollama....387 9.3.3 Local Installation and Execution....388 9.3.4 Running Ollama in a Docker Container....391 9.4 Open WebUI for Ollama....394 9.4.1 Installing Open WebUI....395 9.4.2 Using Custom Documents in Open WebUI....397 9.4.3 Custom Workspace Models....400 9.5 Continue....405 9.5.1 Installation....405 9.5.2 Usage....407 9.6 Ollama API....410 9.6.1 Ollama REST API....410 9.6.2 Libraries for Accessing the Ollama API....413 9.7 Tabby....415 9.7.1 Installing the Tabby Server and the Plug-In....415 9.7.2 Usage....416 9.8 Conclusion....419 10 Automated Code Processing....421 10.1 OpenAI API....422 10.1.1 Setting Up an API Account....423 10.1.2 Hello, World!....424 10.1.3 Formulating the Prompt....427 10.1.4 Chat System....429 10.1.5 Processing the Response....432 10.1.6 Uploading and Downloading Files....434 10.1.7 Uploads for Special Applications....436 10.1.8 Playground....436 10.2 Ollama API....438 10.2.1 Manipulating Code....439 10.3 Groq API....441 10.4 Example: Automated Commenting of Code....443 10.4.1 Real-Life Experience....445 10.4.2 Extracting Code from the Response....448 10.4.3 Genuine Errors....449 10.4.4 Trouble with Large Code Files....450 10.4.5 Translating Existing Comments....452 10.4.6 Conclusion....453 10.5 Example: From Python 2 to Python 3....455 10.5.1 Real-Life Experience....456 11 Level 3 Tools: OpenHands and Aider....459 11.1 OpenHands....461 11.1.1 Installation....463 11.1.2 The Web Interface....465 11.2 Using OpenHands....470 11.2.1 Not Too Much at Once!....473 11.2.2 Conclusion....474 11.3 Aider....476 11.3.1 Installation....476 11.3.2 Start....478 11.3.3 Aider Commands....478 11.3.4 Multiline Prompts....481 11.3.5 Coding Rules and Conventions....481 11.3.6 Aider in the Web Browser....481 11.4 Using Aider....483 11.4.1 Example 1: Sorting Photos....483 11.4.2 Example 2: Web Scraping....490 11.4.3 Example 3: Implementing Changes in a Large Project....493 11.4.4 More Prompting Examples and Video Tips....494 12 Retrieval-Augmented Generation and Text-to-SQL....496 12.1 RAG Quick Start....497 12.2 The Viel-Falter (Many Butterflies) Project....502 12.3 Loading Documents....504 12.3.1 SimpleDirectoryReader and SimpleWebPageReader....505 12.4 Creating an Index....507 12.4.1 The Embedding Model....509 12.5 Vector Store Databases....512 12.6 RAG Queries....516 12.6.1 Source Code....518 12.6.2 Conclusion....521 12.7 Text-to-SQL....522 12.7.1 Database Export from MongoDB to SQLite....522 12.7.2 Text-to-SQL with LlamaIndex....527 12.7.3 Sample Queries....529 12.7.4 Conclusion....536 13 Risks and Outlook....538 13.1 Issues and Limitations of Using AI Tools....539 13.1.1 Old, Cumbersome Code....539 13.1.2 The Question of Maintainability....540 13.1.3 Privacy....540 13.1.4 A New Kind of Dependency....542 13.1.5 Learning to Program in the Age of AI....543 13.2 Exemplary AI Failure....544 13.2.1 Outdated Information....544 13.2.2 Hallucinations....547 13.2.3 Logic Errors....549 13.2.4 Security Issues....551 13.2.5 Less Than Ideal Solutions....556 13.3 Ethical Issues....561 13.3.1 The Origin of AI Knowledge....561 13.3.2 Jobless IT Experts....563 13.3.3 Unlimited Energy Consumption....565 13.4 Conclusions and Outlook....567 13.4.1 Better Results with More Prior Knowledge and Experience....567 13.4.2 Cloud or Local AI?....568 13.4.3 Quality Enhancement through Training with AI-Generated Code....570 13.4.4 The Coming Few Years....570 13.4.5 Conclusion....572 The Authors....574 Index....576 Service Pages....596 Legal Notes....600