Data Layer

Goal

This snapshot advances Cedarline Post by teaching you to persist authors and posts with SQLite.

Every numbered folder is a complete app. Run this stage independently, then compare it with the previous folder.

Prerequisites

Use Go 1.22+, a terminal, and a code editor. You should recognize packages, functions, and HTTP verbs.

Port 8081 must be free. Copy .env.example before starting. Stages from the data layer use a per-snapshot SQLite file (no Docker required).

• Go 1.22 or newer
• A code editor and terminal
• Optional: Docker only if you prefer another database later

Concepts

database/sql plus a SQLite driver stores users and posts. Each snapshot uses its own database file so stages stay independent.

Keep handlers thin: routes accept input, SQL and helpers enforce rules, and html/template escapes output by default.

Walkthrough

Open DATABASE_PATH, migrate tables, seed Ada and Grace, and list posts on the home page.

Read the example, then open the matching snapshot. The repository includes the surrounding setup and error handling.

db, err = sql.Open("sqlite", dbPath)
must(migrate())
must(seed())

Run and verify

Enter 04-Data-Layer, copy .env.example, run go mod tidy, and start the server on port 8081.

Open http://127.0.0.1:8081. Watch the terminal for validation and database errors.

git clone https://github.com/michaeldunga1/fcc-go-blog.git
cd fcc-go-blog/04-Data-Layer
cp .env.example .env
go mod tidy
go run .

Troubleshooting

If the home page is empty after a bad migration, delete the .db file and restart.

Missing module errors usually mean go mod tidy was not run in this snapshot. For SQLite failures, delete a corrupt *.db file and restart so migrate/seed can recreate it.

• Read the first error first
• Restart after environment changes
• Never commit .env or *.db

Try this

Add a minimum title length check before insert.

Test a happy path and one invalid or unauthorized request.

• Make one small change
• Test it in the browser
• Compare with the next snapshot only after it works