init.

2025-11-12 19:55:29 +08:00
commit deec440038
7 changed files with 319 additions and 0 deletions
--- a/.gitignore
+++ b/.gitignore
@@ -0,0 +1,4 @@
+.env
+.envrc
+mysql/
+run_db.sh
--- a/db.go
+++ b/db.go
@@ -0,0 +1,30 @@
+package main
+
+import (
+	"context"
+	"database/sql"
+	"log"
+	"os"
+)
+
+func openDB() (*sql.DB, error) {
+	dsn := os.Getenv("MYSQL_DSN")
+	if dsn == "" {
+		log.Fatal("MYSQL_DSN is empty!")
+	}
+	return sql.Open("mysql", dsn)
+}
+
+func migrate(ctx context.Context, db *sql.DB) error {
+	ddl := `
+CREATE TABLE IF NOT EXISTS students (
+  id BIGINT PRIMARY KEY AUTO_INCREMENT,
+  name VARCHAR(100) NOT NULL,
+  age INT NOT NULL,
+  email VARCHAR(255) NOT NULL UNIQUE,
+  created_at TIMESTAMP NOT NULL DEFAULT CURRENT_TIMESTAMP,
+  updated_at TIMESTAMP NOT NULL DEFAULT CURRENT_TIMESTAMP ON UPDATE CURRENT_TIMESTAMP
+) ENGINE=InnoDB DEFAULT CHARSET=utf8mb4;`
+	_, err := db.ExecContext(ctx, ddl)
+	return err
+}
--- a/go.mod
+++ b/go.mod
@@ -0,0 +1,8 @@
+module work3
+
+go 1.25.4
+
+require (
+	filippo.io/edwards25519 v1.1.0 // indirect
+	github.com/go-sql-driver/mysql v1.9.3 // indirect
+)
--- a/go.sum
+++ b/go.sum
@@ -0,0 +1,4 @@
+filippo.io/edwards25519 v1.1.0 h1:FNf4tywRC1HmFuKW5xopWpigGjJKiJSV0Cqo0cJWDaA=
+filippo.io/edwards25519 v1.1.0/go.mod h1:BxyFTGdWcka3PhytdK4V28tE5sGfRvvvRV7EaN4VDT4=
+github.com/go-sql-driver/mysql v1.9.3 h1:U/N249h2WzJ3Ukj8SowVFjdtZKfu9vlLZxjPXV1aweo=
+github.com/go-sql-driver/mysql v1.9.3/go.mod h1:qn46aNg1333BRMNU69Lq93t8du/dwxI64Gl8i5p1WMU=
--- a/handler.go
+++ b/handler.go
@@ -0,0 +1,197 @@
+package main
+
+import (
+	"context"
+	"database/sql"
+	"encoding/json"
+	"errors"
+	"net/http"
+	"strconv"
+	"strings"
+	"time"
+)
+
+func healthHandler(w http.ResponseWriter, r *http.Request) {
+	now := time.Now().Format(time.RFC3339)
+	ok(w, &map[string]string{"status": "UP", "time": now})
+}
+
+func studentsHandler(w http.ResponseWriter, r *http.Request) {
+	switch r.Method {
+	case http.MethodGet:
+		listStudents(w, r)
+	case http.MethodPost:
+		createStudent(w, r)
+	default:
+		w.Header().Set("Allow", "GET, POST")
+		fail(w, http.StatusMethodNotAllowed, "method not allowed")
+	}
+}
+
+func studentByIDHandler(w http.ResponseWriter, r *http.Request) {
+	idStr := strings.TrimPrefix(r.URL.Path, "/students/")
+	id, err := strconv.ParseInt(idStr, 10, 64)
+	if err != nil {
+		fail(w, http.StatusBadRequest, "invalid student id")
+		return
+	}
+
+	switch r.Method {
+	case http.MethodGet:
+		getStudent(w, r, id)
+	case http.MethodPut:
+		updateStudent(w, r, id)
+	case http.MethodDelete:
+		deleteStudent(w, r, id)
+	default:
+		w.Header().Set("Allow", "GET, PUT, DELETE")
+		fail(w, http.StatusMethodNotAllowed, "method not allowed")
+	}
+
+}
+
+func getStudent(w http.ResponseWriter, r *http.Request, id int64) {
+	ctx, cancel := context.WithTimeout(r.Context(), 3*time.Second)
+	defer cancel()
+
+	var s Student
+
+	err := db.QueryRowContext(ctx,
+		`SELECT id,name,age,email,created_at,updated_at FROM students WHERE id=?`, id,
+	).Scan(&s.ID, &s.Name, &s.Age, &s.Email, &s.CreatedAt, &s.UpdatedAt)
+	if errors.Is(err, sql.ErrNoRows) {
+		fail(w, http.StatusNotFound, "student not found")
+		return
+	} else if err != nil {
+		fail(w, http.StatusInternalServerError, "db query error: "+err.Error())
+		return
+	}
+	ok(w, &s)
+}
+
+func updateStudent(w http.ResponseWriter, r *http.Request, id int64) {
+	if ct := r.Header.Get("Content-Type"); !strings.HasPrefix(strings.ToLower(ct), "application/json") {
+		fail(w, http.StatusUnsupportedMediaType, "Content-Type must be application/json")
+		return
+	}
+
+	var in struct {
+		Name  string `json:"name"`
+		Age   int    `json:"age"`
+		Email string `json:"email"`
+	}
+	if err := json.NewDecoder(r.Body).Decode(&in); err != nil {
+		fail(w, http.StatusBadRequest, "invalid json: "+err.Error())
+		return
+	}
+
+	ctx, cancel := context.WithTimeout(r.Context(), 3*time.Second)
+	defer cancel()
+
+	res, err := db.ExecContext(ctx,
+		`UPDATE students SET name=?, age=?, email=? WHERE id=?`,
+		in.Name, in.Age, in.Email, id)
+	if err != nil {
+		if strings.Contains(strings.ToLower(err.Error()), "duplicate") {
+			fail(w, http.StatusConflict, "email already exists")
+			return
+		}
+		fail(w, http.StatusInternalServerError, "update error: "+err.Error())
+		return
+	}
+	n, _ := res.RowsAffected()
+	if n == 0 {
+		fail(w, http.StatusNotFound, "student not found")
+		return
+	}
+
+	getStudent(w, r, id)
+}
+
+func deleteStudent(w http.ResponseWriter, r *http.Request, id int64) {
+	ctx, cancel := context.WithTimeout(r.Context(), 3*time.Second)
+	defer cancel()
+
+	res, err := db.ExecContext(ctx, `DELETE FROM students WHERE id=?`, id)
+	if err != nil {
+		fail(w, http.StatusInternalServerError, "delete error: "+err.Error())
+		return
+	}
+	n, _ := res.RowsAffected()
+	if n == 0 {
+		fail(w, http.StatusNotFound, "student not found")
+		return
+	}
+
+	ok(w, &map[string]any{"deleted": id})
+}
+
+func createStudent(w http.ResponseWriter, r *http.Request) {
+	if ct := r.Header.Get("Content-Type"); !strings.HasPrefix(strings.ToLower(ct), "application/json") {
+		fail(w, http.StatusUnsupportedMediaType, "Context-Type must be application/json")
+		return
+	}
+	var in struct {
+		Name  string `json:"name"`
+		Age   int    `json:"age"`
+		Email string `json:"email"`
+	}
+	if err := json.NewDecoder(r.Body).Decode(&in); err != nil {
+		fail(w, http.StatusBadRequest, "invalid json: "+err.Error())
+		return
+	}
+	if strings.TrimSpace(in.Name) == "" || in.Age <= 0 || strings.TrimSpace(in.Email) == "" {
+		fail(w, http.StatusBadRequest, "name/age/email required")
+		return
+	}
+
+	ctx, cancel := context.WithTimeout(r.Context(), 3*time.Second)
+	defer cancel()
+
+	res, err := db.ExecContext(ctx,
+		`INSERT INTO students(name, age, email) VALUES(?,?,?)`,
+		in.Name, in.Age, in.Email)
+	if err != nil {
+		fail(w, http.StatusInternalServerError, "insert error: "+err.Error())
+		return
+	}
+	id, _ := res.LastInsertId()
+
+	var out Student
+	err = db.QueryRowContext(ctx,
+		`SELECT id,name,age,email,created_at,updated_at FROM students WHERE id=?`, id,
+	).Scan(&out.ID, &out.Name, &out.Age, &out.Email, &out.CreatedAt, &out.UpdatedAt)
+	if err != nil {
+		fail(w, http.StatusInternalServerError, "fetch created row error: "+err.Error())
+		return
+	}
+
+	created(w, "/students/"+strconv.FormatInt(out.ID, 10), &out)
+}
+
+func listStudents(w http.ResponseWriter, r *http.Request) {
+	ctx, cancel := context.WithTimeout(r.Context(), 3*time.Second)
+	defer cancel()
+	rows, err := db.QueryContext(ctx,
+		`SELECT id,name,age,email,created_at,updated_at FROM students ORDER BY id`)
+	if err != nil {
+		fail(w, http.StatusInternalServerError, "db query error: "+err.Error())
+		return
+	}
+	defer rows.Close()
+
+	var items []Student
+	for rows.Next() {
+		var s Student
+		if err := rows.Scan(&s.ID, &s.Name, &s.Age, &s.Email, &s.CreatedAt, &s.UpdatedAt); err != nil {
+			fail(w, http.StatusInternalServerError, "scan error: "+err.Error())
+			return
+		}
+		items = append(items, s)
+	}
+	if err := rows.Err(); err != nil {
+		fail(w, http.StatusInternalServerError, "rows error: "+err.Error())
+		return
+	}
+	ok(w, &items)
+}
--- a/main.go
+++ b/main.go
@@ -0,0 +1,45 @@
+package main
+
+import (
+	"context"
+	"database/sql"
+	"log"
+	"net/http"
+	"time"
+
+	_ "github.com/go-sql-driver/mysql"
+)
+
+var db *sql.DB
+
+type Student struct {
+	ID        int64     `json:"id"`
+	Name      string    `json:"name"`
+	Age       int       `json:"age"`
+	Email     string    `json:"email"`
+	CreatedAt time.Time `json:"created_at"`
+	UpdatedAt time.Time `json:"updated_at"`
+}
+
+func main() {
+	mux := http.NewServeMux()
+	mux.HandleFunc("/health", healthHandler)
+	mux.HandleFunc("/students", studentsHandler)
+	mux.HandleFunc("/students/", studentByIDHandler)
+
+	var err error
+	db, err = openDB()
+	if err != nil {
+		log.Fatal(err)
+	}
+
+	if err = migrate(context.Background(), db); err != nil {
+		log.Fatal("migrate error: "+err.Error())
+	}
+
+	addr := ":8080"
+	log.Printf("Start server at %s\n", addr)
+	if err := http.ListenAndServe(addr, mux); err != nil {
+		log.Fatal(err)
+	}
+}
--- a/respose.go
+++ b/respose.go
@@ -0,0 +1,31 @@
+package main
+
+import (
+	"encoding/json"
+	"net/http"
+)
+
+type Result[T any] struct {
+	Code    int    `json:"code"`
+	Message string `json:"message"`
+	Data    *T     `json:"data,omitempty"`
+}
+
+func writeJSON[T any](w http.ResponseWriter, status int, payload Result[T]) {
+	w.Header().Set("Content-Type", "application/json; charset=utf-8")
+	w.WriteHeader(status)
+	json.NewEncoder(w).Encode(payload)
+}
+
+func ok[T any](w http.ResponseWriter, data *T) {
+	writeJSON(w, http.StatusOK, Result[T]{Code: 0, Message: "OK", Data: data})
+}
+
+func created[T any](w http.ResponseWriter, location string, data *T) {
+	w.Header().Set("Location", location)
+	writeJSON(w, http.StatusCreated, Result[T]{Code: 0, Message: "Created", Data: data})
+}
+
+func fail(w http.ResponseWriter, status int, msg string) {
+	writeJSON[any](w, status, Result[any]{Code: status, Message: msg, Data: nil})
+}