From 5924ded23d79f15c989fe2f69a5d6745b32a12c6 Mon Sep 17 00:00:00 2001
From: Luke Granger-Brown <hg@lukegb.com>
Date: Wed, 31 Mar 2021 21:19:57 +0000
Subject: [PATCH] go/twitterchiver/viewer: switch media to gocloud s3

---
 go/twitterchiver/default.nix      |  3 +++
 go/twitterchiver/viewer/viewer.go | 45 ++++++++++++++++++++++++++++---
 2 files changed, 44 insertions(+), 4 deletions(-)

diff --git a/go/twitterchiver/default.nix b/go/twitterchiver/default.nix
index 6872f2c142..cbc25f85e7 100644
--- a/go/twitterchiver/default.nix
+++ b/go/twitterchiver/default.nix
@@ -23,6 +23,9 @@
       depot.third_party.gopkgs."github.com".jackc.pgtype
       depot.third_party.gopkgs."github.com".jackc.pgx.v4.pgxpool
       depot.third_party.gopkgs."github.com".pomerium.sdk-go
+      depot.third_party.gopkgs."gocloud.dev".blob
+      depot.third_party.gopkgs."gocloud.dev".blob.s3blob
+      depot.third_party.gopkgs."gocloud.dev".gcerrors
     ];
     dockerData = [ (
       depot.pkgs.runCommand "source" {} ''
diff --git a/go/twitterchiver/viewer/viewer.go b/go/twitterchiver/viewer/viewer.go
index a531fc56e9..7c85e3cb4c 100644
--- a/go/twitterchiver/viewer/viewer.go
+++ b/go/twitterchiver/viewer/viewer.go
@@ -24,13 +24,18 @@ import (
 	"github.com/jackc/pgtype"
 	"github.com/jackc/pgx/v4/pgxpool"
 	pomerium "github.com/pomerium/sdk-go"
+	"gocloud.dev/blob"
+	"gocloud.dev/gcerrors"
+
+	_ "gocloud.dev/blob/s3blob"
 )
 
 var (
+	listen           = flag.String("listen", ":8080", "Listen address")
 	databaseURL      = flag.String("database_url", "", "Database URL")
 	userMapping      = userMap{}
 	localDisableAuth = flag.String("local_auth_override_user", "", "Disable authn/authz - used for dev - set to username")
-	mediaDirectory   = flag.String("media_dir", "/media", "Archived media directory")
+	mediaURL         = flag.String("media_url", "s3://public-lukegb-twitterchiver?endpoint=objdump.zxcvbnm.ninja&region=london", "Blob URL")
 
 	funcMap = template.FuncMap{
 		"rewriteURL":  rewriteURL,
@@ -40,6 +45,10 @@ var (
 	tweetsTmpl = template.Must(template.New("tweets.html").Funcs(funcMap).ParseFiles("templates/tweets.html"))
 )
 
+const (
+	redirectExpiry = 5 * time.Minute
+)
+
 func init() {
 	flag.Var(userMapping, "user_to_twitter", "Space-separated list of <username>:<comma-separated Twitter usernames>")
 }
@@ -115,6 +124,11 @@ func main() {
 	flag.Parse()
 	ctx := context.Background()
 
+	mediaBucket, err := blob.OpenBucket(ctx, *mediaURL)
+	if err != nil {
+		log.Fatalf("blob.OpenBucket: %v", err)
+	}
+
 	pool, err := pgxpool.Connect(ctx, *databaseURL)
 	if err != nil {
 		log.Fatalf("pgxpool.Connect: %v", err)
@@ -161,7 +175,30 @@ func main() {
 		fmt.Fprintf(rw, "<p>%s</p>", wrap)
 	}
 
-	authR.PathPrefix("/media/").Handler(http.StripPrefix("/media/", http.FileServer(http.Dir(*mediaDirectory))))
+	authR.PathPrefix("/media/{filepath:.*}").HandlerFunc(func(rw http.ResponseWriter, r *http.Request) {
+		ctx := r.Context()
+		vars := mux.Vars(r)
+		_, err := userFromContext(ctx)
+		if err != nil {
+			http.Error(rw, fmt.Errorf("userFromContext: %w", err).Error(), http.StatusInternalServerError)
+			return
+		}
+		u, err := mediaBucket.SignedURL(ctx, vars["filepath"], &blob.SignedURLOptions{
+			Expiry: redirectExpiry,
+		})
+		switch gcerrors.Code(err) {
+		case gcerrors.NotFound:
+			// This is unlikely to get returned.
+			http.Error(rw, "not found", http.StatusNotFound)
+			return
+		case gcerrors.OK:
+			http.Redirect(rw, r, u, http.StatusFound)
+			return
+		default:
+			log.Printf("media SignedURL: %v", vars["filepath"], err)
+		}
+		http.Error(rw, err.Error(), http.StatusInternalServerError)
+	})
 	authR.HandleFunc("/", func(rw http.ResponseWriter, r *http.Request) {
 		ctx := r.Context()
 		user, err := userFromContext(ctx)
@@ -542,8 +579,8 @@ LIMIT $2
 		}
 	})
 
-	log.Printf("now listening on :8080")
-	log.Print(http.ListenAndServe(":8080", r))
+	log.Printf("now listening on %s", *listen)
+	log.Print(http.ListenAndServe(*listen, r))
 }
 func agoFriendly(now, at time.Time) string {
 	ago := now.Sub(at)