From 004ea1c55b01436e0f71eddc174fa11789ea63e3 Mon Sep 17 00:00:00 2001
From: Marvin Wichmann <me@marvin-wichmann.de>
Date: Sat, 27 May 2023 12:59:16 +0200
Subject: [PATCH] fix(fiber): Fix fiber returning 500 internal server error

https://github.com/awslabs/aws-lambda-go-api-proxy/commit/fde59295b7aa31f7d8f65997da1a94bad8f69303 caused a regression
in the fiber adapter logic as we previously would try to get the source IP from nil, which
internally would just return an empty string.

Since above commit, the RemoteAddr is not nil anymore, but is lacking the required port
that is needed in order to parse it as a *TCPAddr

This commit makes sure the port section is always added if it does not exist. Furthermore, it
adds a test that prevents this from happening again and we now have logging in place.
---
 fiber/adapter.go          | 17 ++++++++++++++---
 fiber/fiberlambda_test.go | 33 +++++++++++++++++++++++++++++++++
 2 files changed, 47 insertions(+), 3 deletions(-)

diff --git a/fiber/adapter.go b/fiber/adapter.go
index 6da955f..592674e 100644
--- a/fiber/adapter.go
+++ b/fiber/adapter.go
@@ -5,9 +5,12 @@ package fiberadapter
 
 import (
 	"context"
-	"io/ioutil"
+	"fmt"
+	"io"
+	"log"
 	"net"
 	"net/http"
+	"strings"
 
 	"github.com/aws/aws-lambda-go/events"
 	"github.com/gofiber/fiber/v2"
@@ -103,7 +106,7 @@ func (f *FiberLambda) adaptor(w http.ResponseWriter, r *http.Request) {
 	defer fasthttp.ReleaseRequest(req)
 
 	// Convert net/http -> fasthttp request
-	body, err := ioutil.ReadAll(r.Body)
+	body, err := io.ReadAll(r.Body)
 	if err != nil {
 		http.Error(w, utils.StatusMessage(fiber.StatusInternalServerError), fiber.StatusInternalServerError)
 		return
@@ -129,8 +132,16 @@ func (f *FiberLambda) adaptor(w http.ResponseWriter, r *http.Request) {
 		}
 	}
 
-	remoteAddr, err := net.ResolveTCPAddr("tcp", r.RemoteAddr)
+	// We need to make sure the net.ResolveTCPAddr call works as it expects a port
+	addrWithPort := r.RemoteAddr
+	if !strings.Contains(r.RemoteAddr, ":") {
+		addrWithPort = r.RemoteAddr + ":80" // assuming a default port
+	}
+
+	remoteAddr, err := net.ResolveTCPAddr("tcp", addrWithPort)
 	if err != nil {
+		fmt.Printf("could not resolve TCP address for addr %s\n", r.RemoteAddr)
+		log.Println(err)
 		http.Error(w, utils.StatusMessage(fiber.StatusInternalServerError), fiber.StatusInternalServerError)
 		return
 	}
diff --git a/fiber/fiberlambda_test.go b/fiber/fiberlambda_test.go
index 75846e5..7813911 100644
--- a/fiber/fiberlambda_test.go
+++ b/fiber/fiberlambda_test.go
@@ -39,6 +39,39 @@ var _ = Describe("FiberLambda tests", func() {
 		})
 	})
 
+	Context("RemoteAddr handling", func() {
+		It("Properly parses the IP address", func() {
+			app := fiber.New()
+			app.Get("/ping", func(c *fiber.Ctx) error {
+				// make sure the ip address is actually set properly
+				Expect(c.Context().RemoteAddr().String()).To(Equal("8.8.8.8:80"))
+				return c.SendString("pong")
+			})
+
+			adapter := fiberadaptor.New(app)
+
+			req := events.APIGatewayProxyRequest{
+				Path:       "/ping",
+				HTTPMethod: "GET",
+				RequestContext: events.APIGatewayProxyRequestContext{
+					Identity: events.APIGatewayRequestIdentity{
+						SourceIP: "8.8.8.8",
+					},
+				},
+			}
+
+			resp, err := adapter.ProxyWithContext(context.Background(), req)
+
+			Expect(err).To(BeNil())
+			Expect(resp.StatusCode).To(Equal(200))
+
+			resp, err = adapter.Proxy(req)
+
+			Expect(err).To(BeNil())
+			Expect(resp.StatusCode).To(Equal(200))
+		})
+	})
+
 	Context("Request header", func() {
 		It("Check pass canonical header to fiber", func() {
 			app := fiber.New()