Go Mini Projects — Build Real-World Go Applications from Scratch

package main

import (
    "github.com/gin-gonic/gin"
)

type Task struct {
    ID   int    `json:"id"`
    Name string `json:"name" binding:"required"`
    Done bool   `json:"done"`
}

var tasks = []Task{}
var nextID = 1

func main() {
    r := gin.Default()

    r.GET("/tasks", func(c *gin.Context) {
        c.JSON(200, tasks)
    })

    r.POST("/tasks", func(c *gin.Context) {
        var task Task
        if err := c.ShouldBindJSON(&task); err != nil {
            c.JSON(400, gin.H{"error": err.Error()})
            return
        }
        task.ID = nextID
        nextID++
        tasks = append(tasks, task)
        c.JSON(201, task)
    })

    r.DELETE("/tasks/:id", func(c *gin.Context) {
        id, _ := strconv.Atoi(c.Param("id"))
        for i, t := range tasks {
            if t.ID == id {
                tasks = append(tasks[:i], tasks[i+1:]...)
                c.JSON(200, gin.H{"deleted": id})
                return
            }
        }
        c.JSON(404, gin.H{"error": "not found"})
    })

    r.Run(":8080")
}

package main

import "github.com/spf13/cobra"

var tasks []string

func main() {
    root := &cobra.Command{Use: "task"}

    root.AddCommand(&cobra.Command{
        Use: "add [task]",
        Run: func(cmd *cobra.Command, args []string) {
            tasks = append(tasks, args[0])
            fmt.Printf("Added: %s\n", args[0])
        },
    })

    root.AddCommand(&cobra.Command{
        Use: "list",
        Run: func(cmd *cobra.Command, args []string) {
            for i, t := range tasks {
                fmt.Printf("%d. %s\n", i+1, t)
            }
        },
    })

    root.Execute()
}

package main

import (
    "crypto/rand"
    "encoding/hex"
    "net/http"
    "sync"
)

type Store struct {
    mu     sync.RWMutex
    urls   map[string]string
}

func (s *Store) Shorten(original string) string {
    s.mu.Lock()
    defer s.mu.Unlock()
    bytes := make([]byte, 3)
    rand.Read(bytes)
    key := hex.EncodeToString(bytes)
    s.urls[key] = original
    return key
}

func (s *Store) Resolve(key string) (string, bool) {
    s.mu.RLock()
    defer s.mu.RUnlock()
    val, ok := s.urls[key]
    return val, ok
}

func main() {
    r := gin.Default()

    r.Static("/static", "./public")

    r.POST("/upload", func(c *gin.Context) {
        file, _ := c.FormFile("file")
        dst := filepath.Join("./uploads", file.Filename)
        c.SaveUploadedFile(file, dst)
        c.JSON(200, gin.H{"path": dst})
    })

    r.GET("/download/:name", func(c *gin.Context) {
        name := c.Param("name")
        c.File(filepath.Join("./uploads", name))
    })

    r.Run(":8080")
}