From 07d574acd9feaf9d4994c914b022f227c16e132f Mon Sep 17 00:00:00 2001
From: Darius Rapalis <info@rdarius.lt>
Date: Sun, 16 Mar 2025 11:24:00 +0200
Subject: [PATCH] url signing

---
 handler_upload_video.go | 10 ++++++++--
 handler_video_meta.go   | 23 +++++++++++++++++++++--
 main.go                 | 35 +++++++++++++++++++++++++++++++++++
 3 files changed, 64 insertions(+), 4 deletions(-)

diff --git a/handler_upload_video.go b/handler_upload_video.go
index d4964c6..d5d7562 100644
--- a/handler_upload_video.go
+++ b/handler_upload_video.go
@@ -163,7 +163,7 @@ func (cfg *apiConfig) handlerUploadVideo(w http.ResponseWriter, r *http.Request)
 		return
 	}
 
-	url := fmt.Sprintf("http://%s.s3.%s.amazonaws.com/%s", cfg.s3Bucket, cfg.s3Region, fileName)
+	url := fmt.Sprintf("%s,%s", cfg.s3Bucket, fileName)
 
 	video.VideoURL = &url
 
@@ -179,5 +179,11 @@ func (cfg *apiConfig) handlerUploadVideo(w http.ResponseWriter, r *http.Request)
 		return
 	}
 
-	respondWithJSON(w, http.StatusOK, video)
+	vid, err := cfg.dbVideoToSignedVideo(video)
+	if err != nil {
+		respondWithError(w, http.StatusInternalServerError, "Couldn't convert video to signed video", err)
+		return
+	}
+
+	respondWithJSON(w, http.StatusOK, vid)
 }
diff --git a/handler_video_meta.go b/handler_video_meta.go
index 3266038..6f494aa 100644
--- a/handler_video_meta.go
+++ b/handler_video_meta.go
@@ -95,7 +95,12 @@ func (cfg *apiConfig) handlerVideoGet(w http.ResponseWriter, r *http.Request) {
 		return
 	}
 
-	respondWithJSON(w, http.StatusOK, video)
+	vid, err := cfg.dbVideoToSignedVideo(video)
+	if err != nil {
+		respondWithError(w, http.StatusInternalServerError, "Couldn't convert video to signed video", err)
+		return
+	}
+	respondWithJSON(w, http.StatusOK, vid)
 }
 
 func (cfg *apiConfig) handlerVideosRetrieve(w http.ResponseWriter, r *http.Request) {
@@ -116,5 +121,19 @@ func (cfg *apiConfig) handlerVideosRetrieve(w http.ResponseWriter, r *http.Reque
 		return
 	}
 
-	respondWithJSON(w, http.StatusOK, videos)
+	var vids []database.Video
+	if len(videos) > 0 {
+		for _, video := range videos {
+			vid, err := cfg.dbVideoToSignedVideo(video)
+			if err != nil {
+				respondWithError(w, http.StatusInternalServerError, "Couldn't convert video to signed video", err)
+				return
+			}
+			vids = append(vids, vid)
+		}
+	} else {
+		vids = make([]database.Video, 0)
+	}
+
+	respondWithJSON(w, http.StatusOK, vids)
 }
diff --git a/main.go b/main.go
index 40fc39a..afb34a8 100644
--- a/main.go
+++ b/main.go
@@ -4,13 +4,17 @@ import (
 	"bytes"
 	"context"
 	"encoding/json"
+	"errors"
 	"fmt"
+	"github.com/aws/aws-sdk-go-v2/aws"
 	"github.com/aws/aws-sdk-go-v2/config"
 	"github.com/aws/aws-sdk-go-v2/service/s3"
 	"log"
 	"net/http"
 	"os"
 	"os/exec"
+	"strings"
+	"time"
 
 	"github.com/bootdotdev/learn-file-storage-s3-golang-starter/internal/database"
 
@@ -80,6 +84,37 @@ func processVideoForFastStart(filePath string) (string, error) {
 	return newName, nil
 }
 
+func generatePresignedURL(s3Client *s3.Client, bucket, key string, expireTime time.Duration) (string, error) {
+	presignedClient := s3.NewPresignClient(s3Client)
+	obj, err := presignedClient.PresignGetObject(context.Background(), &s3.GetObjectInput{
+		Bucket: aws.String(bucket),
+		Key:    aws.String(key),
+	}, s3.WithPresignExpires(expireTime))
+	if err != nil {
+		return "", err
+	}
+	return obj.URL, nil
+}
+
+func (cfg *apiConfig) dbVideoToSignedVideo(video database.Video) (database.Video, error) {
+
+	if video.VideoURL == nil {
+		return video, nil
+	}
+
+	pieces := strings.Split(*video.VideoURL, ",")
+	if len(pieces) < 2 {
+		return database.Video{}, errors.New("Invalid video URL")
+	}
+	bucket, key := pieces[0], pieces[1]
+	url, err := generatePresignedURL(cfg.s3Client, bucket, key, time.Second*600)
+	if err != nil {
+		return database.Video{}, err
+	}
+	video.VideoURL = &url
+	return video, nil
+}
+
 func main() {
 	godotenv.Load(".env")