Serve single-page apps

main.go

@@ -31,6 +31,7 @@ type Serve struct {
 	Cors          bool   `help:"Include CORS support (on by default)." default:"true" negatable:""`
 	Dot           bool   `help:"Serve dot files (files prefixed with a '.')." default:"false"`
 	ExplicitIndex bool   `help:"Only serve index.html files if URL path includes it." default:"false"`
+	Spa           bool   `help:"Serve the index.html file for all unknown paths." default:"false"`
 }
 
 func normalizePrefix(base string, prefix string) (string, error) {
@@ -66,7 +67,7 @@ func (s *Serve) handler() http.Handler {
 	dir := http.Dir(s.Dir)
 	mux.Handle(s.Prefix, http.StripPrefix(s.Prefix, http.FileServer(dir)))
 
-	handler := withIndex(string(dir), s.Prefix, s.Dot, s.ExplicitIndex, http.Handler(mux))
+	handler := withIndex(string(dir), s.Prefix, s.Dot, s.ExplicitIndex, s.Spa, http.Handler(mux))
 	if !s.Dot {
 		handler = excludeDot(handler)
 	}
@@ -110,7 +111,7 @@ const (
 //go:embed index.html
 var indexHtml string
 
-func withIndex(dir string, prefix string, dot bool, explicitIndex bool, handler http.Handler) http.Handler {
+func withIndex(dir string, prefix string, dot bool, explicitIndex bool, spa bool, handler http.Handler) http.Handler {
 	indexTemplate := template.Must(template.New("index").Parse(indexHtml))
 	base := filepath.Base(dir)
 	return http.HandlerFunc(func(response http.ResponseWriter, request *http.Request) {
@@ -145,6 +146,13 @@ func withIndex(dir string, prefix string, dot bool, explicitIndex bool, handler
 		}
 
 		if !strings.HasSuffix(urlPath, "/") {
+			if spa {
+				// if not found, serve dir/index.html
+				if _, err := os.Stat(path.Join(dir, urlPath)); errors.Is(err, os.ErrNotExist) {
+					http.ServeFile(response, request, path.Join(dir, "index.html"))
+					return
+				}
+			}
 			handler.ServeHTTP(response, request)
 			return
 		}

readme.md

@@ -3,17 +3,19 @@
 Serve files via HTTP.
 
 ```
-Usage: serve <dir>
+Usage: serve <dir> [flags]
 
 Arguments:
   <dir>    Serve files from this directory.
 
 Flags:
   -h, --help              Show context-sensitive help.
       --port=4000         Listen on this port.
+      --prefix="/"        Prefix all URL paths with this value.
       --[no-]cors         Include CORS support (on by default).
       --dot               Serve dot files (files prefixed with a '.').
       --explicit-index    Only serve index.html files if URL path includes it.
+      --spa               Serve the index.html file for all unknown paths.
 ```
 
 The `serve <dir>` command can be used to browse files in a directory via HTTP.  For example, `serve .` starts a server for browsing the files in the current working directory.  See below for more detail on the [usage](#usage).
@@ -41,6 +43,10 @@ By default, files are served on port 4000 (e.g. `http://localhost:4000`).  To ha
 
 By default, files are served with [CORS headers](https://developer.mozilla.org/en-US/docs/Web/HTTP/CORS).  To turn off this behavior, use the `--no-cors` argument (e.g. `serve --no-cors .`).
 
+### `--prefix`
+
+Strip a prefix from the URL path. For example `--prefix foo` will make it so a request for a url like `http://localhost:4000/foo/bar.html` serves the `bar.html` file in the configured `dir` (instead of `foo/bar.html`).
+
 ### `--dot`
 
 By default, files and directories starting with a `.` will not be listed or served.  To allow browsing `.`-prefixed files, use the `--dot` argument (e.g. `serve --dot .`).
@@ -55,3 +61,7 @@ You can use the `--explicit-index` argument to make it so an existing `index.htm
 | ------------------------- | --------------------------------- | --------------------------------- |
 | `/path/to/dir/`           | existing `index.html` is served   | directory listing is served       |
 | `/path/to/dir/index.html` | redirect to `/path/to/dir/`       | existing `index.html` is served   |
+
+### `--spa`
+
+Serve a single-page app. The `--spa` flag makes it so requests for paths that don't exist in the configured `dir` will be served with the `index.html` page. This allows for client-side routing.