init.

2025-11-12 19:55:29 +08:00
commit deec440038
7 changed files with 319 additions and 0 deletions
--- 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)
+}