Serve static assets from a CDN host if provided

bskyweb/cmd/bskyweb/main.go

@@ -87,6 +87,13 @@ func run(args []string) {
 					Value:    cli.NewStringSlice("https://bsky.app", "https://main.bsky.dev", "https://app.staging.bsky.dev"),
 					EnvVars:  []string{"CORS_ALLOWED_ORIGINS"},
 				},
+				&cli.StringFlag{
+					Name:     "static-cdn-host",
+					Usage:    "scheme, hostname, and port of static content CDN, don't end with a slash",
+					Required: false,
+					Value:    "",
+					EnvVars:  []string{"STATIC_CDN_HOST"},
+				},
 			},
 		},
 	}

bskyweb/cmd/bskyweb/server.go

@@ -41,12 +41,13 @@ type Server struct {
 }
 
 type Config struct {
-	debug       bool
-	httpAddress string
-	appviewHost string
-	ogcardHost  string
-	linkHost    string
-	ipccHost    string
+	debug         bool
+	httpAddress   string
+	appviewHost   string
+	ogcardHost    string
+	linkHost      string
+	ipccHost      string
+	staticCDNHost string
 }
 
 func serve(cctx *cli.Context) error {
@@ -58,6 +59,8 @@ func serve(cctx *cli.Context) error {
 	ipccHost := cctx.String("ipcc-host")
 	basicAuthPassword := cctx.String("basic-auth-password")
 	corsOrigins := cctx.StringSlice("cors-allowed-origins")
+	staticCDNHost := cctx.String("static-cdn-host")
+	staticCDNHost = strings.TrimSuffix(staticCDNHost, "/")
 
 	// Echo
 	e := echo.New()
@@ -94,12 +97,13 @@ func serve(cctx *cli.Context) error {
 		echo:  e,
 		xrpcc: xrpcc,
 		cfg: &Config{
-			debug:       debug,
-			httpAddress: httpAddress,
-			appviewHost: appviewHost,
-			ogcardHost:  ogcardHost,
-			linkHost:    linkHost,
-			ipccHost:    ipccHost,
+			debug:         debug,
+			httpAddress:   httpAddress,
+			appviewHost:   appviewHost,
+			ogcardHost:    ogcardHost,
+			linkHost:      linkHost,
+			ipccHost:      ipccHost,
+			staticCDNHost: staticCDNHost,
 		},
 	}
 
@@ -333,15 +337,21 @@ func (srv *Server) Shutdown() error {
 	return srv.httpd.Shutdown(ctx)
 }
 
+// NewTemplateContext returns a new pongo2 context with some default values.
+func (srv *Server) NewTemplateContext() pongo2.Context {
+	return pongo2.Context{
+		"staticCDNHost": srv.cfg.staticCDNHost,
+	}
+}
+
 func (srv *Server) errorHandler(err error, c echo.Context) {
 	code := http.StatusInternalServerError
 	if he, ok := err.(*echo.HTTPError); ok {
 		code = he.Code
 	}
 	c.Logger().Error(err)
-	data := pongo2.Context{
-		"statusCode": code,
-	}
+	data := srv.NewTemplateContext()
+	data["statusCode"] = code
 	c.Render(code, "error.html", data)
 }
 
@@ -385,18 +395,18 @@ func (srv *Server) LinkProxyMiddleware(url *url.URL) echo.MiddlewareFunc {
 
 // handler for endpoint that have no specific server-side handling
 func (srv *Server) WebGeneric(c echo.Context) error {
-	data := pongo2.Context{}
+	data := srv.NewTemplateContext()
 	return c.Render(http.StatusOK, "base.html", data)
 }
 
 func (srv *Server) WebHome(c echo.Context) error {
-	data := pongo2.Context{}
+	data := srv.NewTemplateContext()
 	return c.Render(http.StatusOK, "home.html", data)
 }
 
 func (srv *Server) WebPost(c echo.Context) error {
 	ctx := c.Request().Context()
-	data := pongo2.Context{}
+	data := srv.NewTemplateContext()
 
 	// sanity check arguments. don't 4xx, just let app handle if not expected format
 	rkeyParam := c.Param("rkey")
@@ -471,7 +481,7 @@ func (srv *Server) WebPost(c echo.Context) error {
 func (srv *Server) WebStarterPack(c echo.Context) error {
 	req := c.Request()
 	ctx := req.Context()
-	data := pongo2.Context{}
+	data := srv.NewTemplateContext()
 	data["requestURI"] = fmt.Sprintf("https://%s%s", req.Host, req.URL.Path)
 	// sanity check arguments. don't 4xx, just let app handle if not expected format
 	rkeyParam := c.Param("rkey")
@@ -509,7 +519,7 @@ func (srv *Server) WebStarterPack(c echo.Context) error {
 
 func (srv *Server) WebProfile(c echo.Context) error {
 	ctx := c.Request().Context()
-	data := pongo2.Context{}
+	data := srv.NewTemplateContext()
 
 	// sanity check arguments. don't 4xx, just let app handle if not expected format
 	handleOrDIDParam := c.Param("handleOrDID")

bskyweb/templates/base.html

@@ -13,8 +13,8 @@
 
   <!-- Hello Humans! API docs at https://atproto.com -->
 
-  <link rel="preload" as="font" type="font/ttf" href="/static/media/InterVariable.c9f788f6e7ebaec75d7c.ttf">
-  <link rel="preload" as="font" type="font/ttf" href="/static/media/InterVariable-Italic.55d6a3f35e9b605ba6f4.ttf">
+  <link rel="preload" as="font" type="font/ttf" href="{{ staticCDNHost }}/static/media/InterVariable.c9f788f6e7ebaec75d7c.ttf">
+  <link rel="preload" as="font" type="font/ttf" href="{{ staticCDNHost }}/static/media/InterVariable-Italic.55d6a3f35e9b605ba6f4.ttf">
 
   <style>
     /**
@@ -64,10 +64,10 @@
   </style>
 
   {% include "scripts.html" %}
-  <link rel="apple-touch-icon" sizes="180x180" href="/static/apple-touch-icon.png">
-  <link rel="icon" type="image/png" sizes="32x32" href="/static/favicon-32x32.png">
-  <link rel="icon" type="image/png" sizes="16x16" href="/static/favicon-16x16.png">
-  <link rel="mask-icon" href="/static/safari-pinned-tab.svg" color="#1185fe">
+  <link rel="apple-touch-icon" sizes="180x180" href="{{ staticCDNHost }}/static/apple-touch-icon.png">
+  <link rel="icon" type="image/png" sizes="32x32" href="{{ staticCDNHost }}/static/favicon-32x32.png">
+  <link rel="icon" type="image/png" sizes="16x16" href="{{ staticCDNHost }}/static/favicon-16x16.png">
+  <link rel="mask-icon" href="{{ staticCDNHost }}/static/safari-pinned-tab.svg" color="#1185fe">
   <meta name="theme-color">
   <meta name="application-name" content="Bluesky">
   <meta name="generator" content="bskyweb">

scripts/post-web-build.js

@@ -23,10 +23,10 @@ const outputFile = entrypoints
     const ext = path.extname(file)
 
     if (ext === '.js') {
-      return `<script defer="defer" src="/static/js/${file}"></script>`
+      return `<script defer="defer" src="{{staticCDNHost}}/static/js/${file}"></script>`
     }
     if (ext === '.css') {
-      return `<link rel="stylesheet" href="/static/css/${file}">`
+      return `<link rel="stylesheet" href="{{staticCDNHost}}/static/css/${file}">`
     }
 
     return ''