catch all fuh real

cmd/web/main.go

@@ -3,6 +3,8 @@ package main
 import (
 	"log"
 	"net/http"
+	"os"
+	"path/filepath"
 
 	"github.com/gorilla/mux"
 	_ "github.com/joho/godotenv/autoload"
@@ -67,7 +69,8 @@ func main() {
 	api.HandleFunc("/schedule/{accountID}", server.UpdateScheduleHandler).Methods(http.MethodPut)
 	api.HandleFunc("/schedule/{accountID}", server.DeleteScheduleHandler).Methods(http.MethodDelete)
 
-	r.PathPrefix("/").HandlerFunc(serveHTML)
+	spa := spaHandler{staticPath: "client/build", indexPath: "index.html"}
+	r.PathPrefix("/").Handler(spa)
 
 	port := ":9000"
 
@@ -76,6 +79,41 @@ func main() {
 	log.Fatalln(http.ListenAndServe(port, r))
 }
 
-func serveHTML(w http.ResponseWriter, r *http.Request) {
-	http.ServeFile(w, r, "client/build/index.html")
+type spaHandler struct {
+	staticPath string
+	indexPath  string
+}
+
+// ServeHTTP inspects the URL path to locate a file within the static dir
+// on the SPA handler. If a file is found, it will be served. If not, the
+// file located at the index path on the SPA handler will be served. This
+// is suitable behavior for serving an SPA (single page application).
+func (h spaHandler) ServeHTTP(w http.ResponseWriter, r *http.Request) {
+	// get the absolute path to prevent directory traversal
+	path, err := filepath.Abs(r.URL.Path)
+	if err != nil {
+		// if we failed to get the absolute path respond with a 400 bad request
+		// and stop
+		http.Error(w, err.Error(), http.StatusBadRequest)
+		return
+	}
+
+	// prepend the path with the path to the static directory
+	path = filepath.Join(h.staticPath, path)
+
+	// check whether a file exists at the given path
+	_, err = os.Stat(path)
+	if os.IsNotExist(err) {
+		// file does not exist, serve index.html
+		http.ServeFile(w, r, filepath.Join(h.staticPath, h.indexPath))
+		return
+	} else if err != nil {
+		// if we got an error (that wasn't that the file doesn't exist) stating the
+		// file, return a 500 internal server error and stop
+		http.Error(w, err.Error(), http.StatusInternalServerError)
+		return
+	}
+
+	// otherwise, use http.FileServer to serve the static dir
+	http.FileServer(http.Dir(h.staticPath)).ServeHTTP(w, r)
 }