backend: add download handler

cmd/main.go

@@ -95,6 +95,8 @@ func run(cfg *config.Config) {
 	router.GET(apiBase+"/config", handlers.HandleConfig)
 	router.POST(apiBase+"/initiate", handlers.HandleInitiate)
 	router.POST(apiBase+"/complete", handlers.HandleComplete)
+	router.GET(apiBase+"/download/*key", handlers.HandleDownload)
+	router.HEAD(apiBase+"/download/*key", handlers.HandleDownload)
 
 	server := &http.Server{
 		Addr:           cfg.Server.Listen,

pkg/config/config.go

@@ -56,7 +56,10 @@ type ServerConfig struct {
 	// Host is the local machine IP Address to bind the HTTP Server to
 	Listen string `mapstructure:"listen"`
 
+	// Directory of frontend static assets
 	Static string `mapstructure:"static"`
+
+	BaseURL string `mapstructure:"base_url"`
 }
 
 // ShortenerConfig contains Link-shortener specific configuration

pkg/handlers/download.go

@@ -0,0 +1,58 @@
+package handlers
+
+import (
+	"fmt"
+	"net/http"
+	"strings"
+	"time"
+
+	"github.com/aws/aws-sdk-go/aws"
+	"github.com/aws/aws-sdk-go/service/s3"
+	"github.com/gin-gonic/gin"
+	"github.com/google/uuid"
+	"github.com/stv0g/gose/pkg/config"
+	"github.com/stv0g/gose/pkg/notifier"
+)
+
+func HandleDownload(c *gin.Context) {
+	var err error
+
+	svc, _ := c.MustGet("s3").(*s3.S3)
+	cfg, _ := c.MustGet("cfg").(*config.Config)
+	notifier, _ := c.MustGet("notifier").(*notifier.Notifier)
+
+	key := c.Param("key")
+	key = key[1:]
+
+	parts := strings.Split(key, "/")
+	if len(parts) != 2 {
+		c.JSON(http.StatusInternalServerError, gin.H{"error": "invalid key"})
+		return
+	}
+
+	if _, err := uuid.Parse(parts[0]); err != nil {
+		c.JSON(http.StatusInternalServerError, gin.H{"error": "invalid uuid in key"})
+		return
+	}
+
+	req, _ := svc.GetObjectRequest(&s3.GetObjectInput{
+		Bucket: aws.String(cfg.S3.Bucket),
+		Key:    aws.String(key),
+	})
+
+	u, _, err := req.PresignRequest(10 * time.Second)
+	if err != nil {
+		c.JSON(http.StatusInternalServerError, gin.H{"error": fmt.Sprintf("failed to presign request: %s", err)})
+		return
+	}
+
+	if notifier != nil && cfg.Notification.Downloads {
+		go func(s3svc *s3.S3, cfg *config.Config, key string) {
+			if err := notifier.Notify(svc, cfg, key, "New download"); err != nil {
+				fmt.Printf("Failed to send notification: %s", err)
+			}
+		}(svc, cfg, key)
+	}
+
+	c.Redirect(http.StatusTemporaryRedirect, u)
+}

pkg/handlers/initiate.go

@@ -71,7 +71,8 @@ func HandleInitiate(c *gin.Context) {
 
 	key := path.Join(uid.String(), req.Filename)
 
-	u := cfg.S3.GetObjectURL(key)
+	u, _ := url.Parse(cfg.Server.BaseURL)
+	u.Path += "api/v1/download/" + key
 	if req.Shorten {
 		if shortener == nil {
 			c.JSON(http.StatusBadRequest, gin.H{"error": "shortened URL requested but nut supported"})
@@ -94,7 +95,6 @@ func HandleInitiate(c *gin.Context) {
 	reqCreateMPU := &s3.CreateMultipartUploadInput{
 		Bucket: aws.String(cfg.S3.Bucket),
 		Key:    aws.String(key),
-		ACL:    aws.String("public-read"),
 		Metadata: aws.StringMap(map[string]string{
 			"uploaded-by": c.ClientIP(),
 			"url":         u.String(),