feat: Add authorization middleware

Author: saulmaldonado

api/middleware/jwt/jwt.go

@@ -0,0 +1,62 @@
+package jwt
+
+import (
+	"agones-minecraft/resource/api/v1/errors"
+	"agones-minecraft/services/auth/jwt"
+	"fmt"
+	"strings"
+
+	"github.com/gin-gonic/gin"
+)
+
+const (
+	HeaderKey  string = "Authorization"
+	ContextKey string = "JWT_SUBJECT"
+)
+
+// returns middleware that will parse JWT token in Authorization header, validate it, verify it
+// and set the userId in the current context as "JWT_SUBJECT"
+func Authorizer() gin.HandlerFunc {
+	return func(c *gin.Context) {
+		v := c.GetHeader(HeaderKey)
+		tokenString := strings.TrimSpace(strings.TrimPrefix(v, "Bearer"))
+
+		if tokenString == "" {
+			c.Errors = append(c.Errors, errors.NewUnauthorizedError(fmt.Errorf("missing access token in Authorization header")))
+			c.Abort()
+			return
+		}
+
+		token, err := jwt.ParseToken(tokenString)
+		if err != nil {
+			c.Errors = append(c.Errors, errors.NewUnauthorizedError(fmt.Errorf("unable to parse token")))
+			c.Abort()
+			return
+		}
+
+		val, _ := token.Get(jwt.RefreshKey)
+
+		if val.(bool) {
+			c.Errors = append(c.Errors, errors.NewUnauthorizedError(fmt.Errorf("token identified as refresh token")))
+			c.Abort()
+			return
+		}
+
+		if err := jwt.ValidateToken(token); err != nil {
+			c.Errors = append(c.Errors, errors.NewUnauthorizedError(err))
+			c.Abort()
+			return
+		}
+
+		if err := jwt.VerifyAccessToken(tokenString); err != nil {
+			c.Errors = append(c.Errors, errors.NewUnauthorizedError(fmt.Errorf("unable to verify access token")))
+			c.Abort()
+			return
+		}
+
+		// Set userId for request context
+		c.Set(ContextKey, token.Subject())
+
+		c.Next()
+	}
+}