first commit

internal/auth/auth.go

@@ -0,0 +1,71 @@
+package auth
+
+import (
+	"context"
+	"encoding/base64"
+	"encoding/json"
+	"github.com/gin-gonic/gin"
+	"github.com/gissleh/stufflog/internal/slerrors"
+	"net/http"
+	"strings"
+)
+
+var contextKey = struct{}{}
+
+func UserID(ctx context.Context) string {
+	if c, ok := ctx.(*gin.Context); ok {
+		return UserID(c.Request.Context())
+	}
+
+	return ctx.Value(&contextKey).(string)
+}
+
+func DummyMiddleware(uuid string) gin.HandlerFunc {
+	return func(c *gin.Context) {
+		c.Request = c.Request.WithContext(
+			context.WithValue(c.Request.Context(), &contextKey, uuid),
+		)
+	}
+}
+
+func abortRequest(c *gin.Context) {
+	c.AbortWithStatusJSON(http.StatusUnauthorized, slerrors.ErrorResponse{
+		Code:    http.StatusUnauthorized,
+		Message: "You're not supposed to be here!",
+	})
+}
+
+// TrustingJwtParserMiddleware is meant to be put behind an AWS API gateway that has already
+// verified this token.
+func TrustingJwtParserMiddleware() gin.HandlerFunc {
+	return func(c *gin.Context) {
+		auth := c.GetHeader("Authorization")
+		split := strings.Split(auth, ".")
+
+		if len(split) >= 3 {
+			data, err := base64.RawStdEncoding.DecodeString(split[1])
+			if err != nil {
+				abortRequest(c)
+				return
+			}
+
+			fields := make(map[string]interface{})
+			err = json.Unmarshal(data, &fields)
+			if err != nil {
+				abortRequest(c)
+				return
+			}
+
+			if sub, ok := fields["sub"].(string); ok {
+				c.Request = c.Request.WithContext(
+					context.WithValue(c.Request.Context(), &contextKey, sub),
+				)
+			} else {
+				abortRequest(c)
+				return
+			}
+		} else {
+			abortRequest(c)
+		}
+	}
+}