雑にbankを作っている

blackbox/bank/main.go

@@ -0,0 +1,214 @@
+package main
+
+import (
+	"database/sql"
+	"encoding/json"
+	"flag"
+	"fmt"
+	"log"
+	"net/http"
+
+	"github.com/go-sql-driver/mysql"
+	"github.com/pkg/errors"
+)
+
+func main() {
+	var (
+		port   = flag.Int("port", 5515, "bank app ranning port")
+		dbhost = flag.String("dbhost", "127.0.0.1", "database host")
+		dbport = flag.Int("dbport", 3306, "database port")
+		dbuser = flag.String("dbuser", "root", "database user")
+		dbpass = flag.String("dbpass", "", "database pass")
+		dbname = flag.String("dbname", "isubank", "database name")
+	)
+
+	flag.Parse()
+
+	addr := fmt.Sprintf(":%d", *port)
+	dbup := *dbuser
+	if *dbpass != "" {
+		dbup += ":" + *dbpass
+	}
+
+	dsn := fmt.Sprintf("%s@tcp(%s:%d)/%s?parseTime=true&loc=Local&charset=utf8mb4", dbup, *dbhost, *dbport, *dbname)
+	db, err := sql.Open("mysql", dsn)
+	if err != nil {
+		log.Fatalf("mysql connect failed. err: %s", err)
+	}
+	server := NewServer(db)
+
+	log.Fatal(http.ListenAndServe(addr, server))
+}
+
+func NewServer(db *sql.DB) *http.ServeMux {
+	server := http.NewServeMux()
+
+	h := &Handler{db}
+
+	h.HandleFunc("/register", c.Register)
+	h.HandleFunc("/add_credit", c.AddCredit)
+	h.HandleFunc("/check_credit", c.CheckCredit)
+	h.HandleFunc("/send_credit", c.SendCredit)
+	h.HandleFunc("/pull_credit", c.PullCredit)
+
+	// default 404
+	server.HandleFunc("/", func(w http.ResponseWriter, r *http.Request) {
+		log.Printf("[INFO] request not found %s", r.URL.RawPath)
+		Error(w, "Not found", 404)
+	})
+	return server
+}
+
+const (
+	ResOK    = `{"status":"ok"}`
+	ResError = `{"status":"ng","error":"%s"}`
+)
+
+func Error(w http.ResponseWriter, err string, code int) {
+	w.Header().Set("Content-Type", "application/json; charset=utf-8")
+	w.Header().Set("X-Content-Type-Options", "nosniff")
+	w.WriteHeader(code)
+	fmt.Fprintln(w, fmt.Sprintf(ResError, err))
+}
+
+func Success(w http.ResponseWriter) {
+	w.Header().Set("Content-Type", "application/json; charset=utf-8")
+	fmt.Fprintln(w, ResOK)
+}
+
+type ReqPram struct {
+	AppID  string `json:"app_id"`
+	BankID string `json:"bank_id"`
+	Price  int64  `json:"price"`
+}
+
+type Handler struct {
+	db *sql.DB
+}
+
+func (s *Handler) Register(w http.ResponseWriter, r *http.Request) {
+	if r.Method != "POST" {
+		Error(w, "method not allowed", http.StatusMethodNotAllowed)
+		return
+	}
+	req := &ReqPram{}
+	if err := json.NewDecoder(r.Body).Decode(req); err != nil {
+		Error(w, "can't parse body", http.StatusBadRequest)
+		return
+	}
+	if req.BankID == "" {
+		Error(w, "bank_id is required", http.StatusBadRequest)
+		return
+	}
+	if _, err := s.db.Exec(`INSERT INTO user (bank_id, created_at) VALUES (?, NOW())`, req.BankID); err != nil {
+		if mysqlError, ok := err.(*mysql.MySQLError); ok {
+			if mysqlError.Number == 1062 {
+				Error(w, "bank_id already exists", http.StatusBadRequest)
+				return
+			}
+		}
+		log.Printf("[WARN] insert user failed. err: %s", err)
+		Error(w, "internal server error", http.StatusInternalServerError)
+	}
+	Success(w)
+}
+
+func (s *Handler) AddCredit(w http.ResponseWriter, r *http.Request) {
+	if r.Method != "POST" {
+		Error(w, "method not allowed", http.StatusMethodNotAllowed)
+		return
+	}
+	req := &ReqPram{}
+	if err := json.NewDecoder(r.Body).Decode(req); err != nil {
+		Error(w, "can't parse body", http.StatusBadRequest)
+		return
+	}
+	if req.BankID == "" {
+		Error(w, "bank_id is required", http.StatusBadRequest)
+		return
+	}
+	if req.Price <= 0 {
+		Error(w, "price must be upper than 0", http.StatusBadRequest)
+		return
+	}
+	userID, _, err := s.getUserID(req.BankID)
+	switch {
+	case err == sql.ErrNoRows:
+		Error(w, "user not found", http.StatusNotFound)
+		return
+	case err != nil:
+		log.Printf("[WARN] get user failed. err: %s", err)
+		Error(w, "internal server error", http.StatusInternalServerError)
+	}
+
+	if err = s.modifyPrice(userID, req.Price, "by add credit API"); err != nil {
+		log.Printf("[WARN] modifyPrice failed. err: %s", err)
+		Error(w, "internal server error", http.StatusInternalServerError)
+	}
+	Success(w)
+}
+
+func (s *Handler) CheckCredit(w http.ResponseWriter, r *http.Request) {
+	if r.Method != "POST" {
+		Error(w, "method not allowed", http.StatusMethodNotAllowed)
+		return
+	}
+	req := &ReqPram{}
+	if err := json.NewDecoder(r.Body).Decode(req); err != nil {
+		Error(w, "can't parse body", http.StatusBadRequest)
+		return
+	}
+	if req.BankID == "" {
+		Error(w, "bank_id is required", http.StatusBadRequest)
+		return
+	}
+	if req.Price <= 0 {
+		Error(w, "price must be upper than 0", http.StatusBadRequest)
+		return
+	}
+	userID, credit, err := s.getUserID(req.BankID)
+	switch {
+	case err == sql.ErrNoRows:
+		Error(w, "user not found", http.StatusNotFound)
+		return
+	case err != nil:
+		log.Printf("[WARN] get user failed. err: %s", err)
+		Error(w, "internal server error", http.StatusInternalServerError)
+	}
+	if credit >= req.Price {
+		Success(w)
+	} else {
+		Error(w, "credit is shorten", http.StatusOK)
+	}
+}
+
+func (s *Handler) SendCredit(w http.ResponseWriter, r *http.Request) {
+	Success(w)
+}
+
+func (s *Handler) PullCredit(w http.ResponseWriter, r *http.Request) {
+	Success(w)
+}
+
+func (s *Handler) getUserID(bankID string) (id, credit int64, err error) {
+	err = s.db.QueryRow(`SELECT id, credit FROM user WHERE bank_id = ? LIMIT 1`, bankID).Scan(&id, &credit)
+	return
+}
+
+func (s *Handler) modifyPrice(userID, price int64, memo string) error {
+	tx, err := s.db.Begin()
+	if err != nil {
+		return errors.Wrap(err, "begin transaction failed")
+	}
+	if _, err = tx.Exec(`INSERT INTO jpyen (user_id, amount, note, created_at) VALUES (?, NOW())`, userID, price, memo); err != nil {
+		return errors.Wrap(err, "insert jpyen failed")
+	}
+	var price int64
+	if err = tx.QueryRow(`SELECT SUM(amount) FROM jpyen WHERE user_id = ?`, userID).Scan(&price); err != nil {
+		return errors.Wrap(err, "calc jpyen failed")
+	}
+	if _, err = tx.Exec(`UPDATE user SET credit = ? WHERE user_id = ?`, price, bankID); err != nil {
+		return errors.Wrap(err, "update user.credit failed")
+	}
+	return tx.Commit()
+}