allow passing in the base server url

cmd/terse/terse.go

@@ -1,6 +1,7 @@
 package main
 
 import (
+	"fmt"
 	"log"
 
 	"github.com/brettlangdon/go-arg"
@@ -10,17 +11,24 @@ import (
 var args struct {
 	MaxEntries int    `arg:"-m,--max,help:max number of links to keep [default: 1000]"`
 	Bind       string `arg:"-b,--bind,help:\"[host]:<port>\" to bind the server to [default: 127.0.0.1:5892]"`
+	ServerURL  string `arg:"-s,--server,help:base server url to generate links as (e.g. \"https://short.domain.com\") [default: \"http://<bind>\"]"`
 }
 
 func main() {
 	// Setup default args
 	args.MaxEntries = 1000
 	args.Bind = "127.0.0.1:5892"
-
 	// Parse args from CLI
 	arg.MustParse(&args)
 
+	if args.ServerURL == "" {
+		args.ServerURL = fmt.Sprintf("http://%s", args.Bind)
+	}
+
 	// Start the server
-	server := terse.NewServer(args.Bind, args.MaxEntries)
-	log.Fatal(server.ListenAndServe())
+	server, err := terse.NewServer(args.Bind, args.MaxEntries, args.ServerURL)
+	if err == nil {
+		err = server.ListenAndServe()
+	}
+	log.Fatal(err)
 }

server.go

@@ -11,7 +11,8 @@ import (
 )
 
 type Handler struct {
-	cache *lru.Cache
+	cache     *lru.Cache
+	serverURL *url.URL
 }
 
 func (handler *Handler) ServeHTTP(w http.ResponseWriter, r *http.Request) {
@@ -61,19 +62,21 @@ func (handler *Handler) HandlePost(w http.ResponseWriter, r *http.Request) {
 	handler.cache.Add(code, cleanUrl)
 
 	// Generate response url
-	codeUrl := &url.URL{
-		Scheme: "https",
-		Host:   r.Host,
-		Path:   "/" + code,
-	}
+	codeUrl := handler.serverURL
+	codeUrl.Path = "/" + code
 	fmt.Fprintf(w, codeUrl.String())
 }
 
-func NewServer(bind string, maxEntries int) *http.Server {
+func NewServer(bind string, maxEntries int, serverURL string) (*http.Server, error) {
+	parsedURL, err := url.ParseRequestURI(serverURL)
+	if err != nil {
+		return nil, err
+	}
 	return &http.Server{
 		Addr: bind,
 		Handler: &Handler{
-			cache: lru.New(maxEntries),
+			cache:     lru.New(maxEntries),
+			serverURL: parsedURL,
 		},
-	}
+	}, nil
 }