#1 add authorization with firebase

Co-authored-by: Tim <timwundenberg@outlook.de>
Reviewed-on: tim/me-fit#2

api/middleware/auth.go

@@ -0,0 +1,28 @@
+package middleware
+
+import (
+	"api/utils"
+	"context"
+	"net/http"
+)
+
+type ContextKey string
+
+const TOKEN_KEY ContextKey = "token"
+
+func EnsureAuth(next http.Handler) http.Handler {
+	return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+		tokenStr := r.Header.Get("Authorization")
+		tokenStr = tokenStr[len("Bearer "):]
+
+		token, err := utils.VerifyToken(tokenStr)
+		if err != nil {
+			http.Error(w, "Unauthorized", http.StatusUnauthorized)
+			return
+		}
+
+		var newContext = context.WithValue(r.Context(), TOKEN_KEY, token)
+
+		next.ServeHTTP(w, r.WithContext(newContext))
+	})
+}