1 files changed, 38 insertions, 12 deletions
diff --git a/resp.go b/resp.go
index f90c486..408dcd3 100644
--- a/resp.go
+++ b/resp.go
@@ -4,22 +4,48 @@
 package main
 
 import (
-	"fmt"
-	"os"
+	"log"
+	"net/http"
+	"path"
 	"strings"
+	"text/template"
 )
 
-func GetBody(pkg string) string {
-	dest := GetDest(os.Getenv("PREFIX"), os.Getenv("DEST"), pkg)
-	return fmt.Sprintf(`<!doctype html>
-<meta name="go-import" content="%s %s %s">
+var body = template.Must(template.New("").Parse(`<!doctype html>
+<meta name="go-import" content="{{.Package}} {{.VCS}} {{.Repository}}">
 <title>go-import-redirect</title>
-`, pkg, os.Getenv("VCS"), dest)
+`))
+
+type bodyData struct{ Package, Repository, VCS string }
+
+type redirector struct{ from, to, vcs string }
+
+var _ http.Handler = &redirector{}
+
+func (h *redirector) ServeHTTP(w http.ResponseWriter, req *http.Request) {
+	if req.Method != http.MethodGet {
+		w.Header().Set("Allow", http.MethodGet)
+		w.WriteHeader(http.StatusMethodNotAllowed)
+		return
+	}
+
+	pkg := path.Join(req.Host, req.URL.Path)
+	if req.URL.Query().Get("go-get") != "1" {
+		w.Header().Set("Location", "https://pkg.go.dev/"+pkg)
+		w.WriteHeader(http.StatusFound)
+		return
+	}
+	dest := h.getRepo(pkg)
+	w.Header().Set("Content-Type", "text/html; charset=utf-8")
+	w.WriteHeader(http.StatusOK)
+	if err := body.Execute(w, bodyData{pkg, dest, h.vcs}); err != nil {
+		log.Println(err)
+	}
 }
 
-func GetDest(srcPrefix, destPrefix, pkg string) string {
-	srcPrefix = strings.TrimRight(srcPrefix, "/")
-	destPrefix = strings.TrimRight(destPrefix, "/")
-	path := strings.TrimLeft(strings.TrimPrefix(pkg, srcPrefix), "/")
-	return destPrefix + "/" + strings.Split(path, "/")[0]
+func (h *redirector) getRepo(pkg string) string {
+	from := strings.TrimRight(h.from, "/")
+	to := strings.TrimRight(h.to, "/")
+	path := strings.TrimLeft(strings.TrimPrefix(pkg, from), "/")
+	return to + "/" + strings.Split(path, "/")[0]
 }