feat(backend): jwt middleware, login with redis rate limit, /auth/me

backend/internal/api/api.go

@@ -0,0 +1,55 @@
+package api
+
+import (
+	"net/http"
+	"strings"
+
+	"github.com/gin-gonic/gin"
+
+	"booklib/internal/auth"
+	"booklib/internal/config"
+	"booklib/internal/redispkg"
+	"booklib/internal/store"
+)
+
+type api struct {
+	cfg *config.Config
+	st  *store.Store
+	rdb *redispkg.R
+}
+
+func err(c *gin.Context, status int, code, msg string) {
+	c.AbortWithStatusJSON(status, gin.H{"error": gin.H{"code": code, "message": msg}})
+}
+
+func (a *api) authMw() gin.HandlerFunc {
+	return func(c *gin.Context) {
+		h := c.GetHeader("Authorization")
+		tok, ok := strings.CutPrefix(h, "Bearer ")
+		if !ok {
+			err(c, http.StatusUnauthorized, "unauthorized", "missing bearer token")
+			return
+		}
+		cl, perr := auth.Parse(a.cfg.JWTSecret, tok)
+		if perr != nil {
+			err(c, http.StatusUnauthorized, "unauthorized", "invalid token")
+			return
+		}
+		c.Set("uid", cl.UID)
+		c.Set("role", cl.Role)
+		c.Next()
+	}
+}
+
+func (a *api) adminOnly() gin.HandlerFunc {
+	return func(c *gin.Context) {
+		if c.GetString("role") != "admin" {
+			err(c, http.StatusForbidden, "forbidden", "admin only")
+			return
+		}
+		c.Next()
+	}
+}
+
+func uid(c *gin.Context) int64    { return c.GetInt64("uid") }
+func isAdmin(c *gin.Context) bool { return c.GetString("role") == "admin" }