feat: better route function

src/main.go

@@ -0,0 +1,15 @@
+package main
+
+import (
+    "log"
+    "net/http"
+)
+
+func main() {
+    http.HandleFunc("/", Route)
+
+    err := http.ListenAndServe(":3000", nil)
+    if err != nil {
+        log.Fatal(err)
+    }
+}

src/route.go

@@ -0,0 +1,58 @@
+package main
+
+import (
+    "context"
+    "fmt"
+    "net/http"
+    "path/filepath"
+    "regexp"
+    "slices"
+)
+
+type URLParam struct{}
+
+type W = http.ResponseWriter
+type R = *http.Request
+
+var routes = []struct {
+    methods []string
+    regex   *regexp.Regexp
+    handler http.HandlerFunc
+}{
+    {[]string{"GET"}, URL(""), func(w W, r R) {
+        http.ServeFile(w, r, filepath.Join("html", "index.html"))
+    }},
+    {[]string{"GET"}, URL("/style\\.css"), func(w W, r R) {
+        http.ServeFile(w, r, "/html/style.css")
+    }},
+    {[]string{"GET"}, URL("/static/.+"), func(w W, r R) {
+        http.ServeFile(w, r, r.URL.Path)
+    }},
+    {[]string{"GET"}, URL("/[^/]+"), func(w W, r R) {
+        http.ServeFile(w, r, filepath.Join("html", r.URL.Path + ".html"))
+    }},
+}
+
+func URL(s string) *regexp.Regexp {
+    return regexp.MustCompile("^" + s + "/?$")
+}
+
+func Route(w http.ResponseWriter, r *http.Request) {
+    for _, rt := range routes {
+        matches := rt.regex.FindStringSubmatch(r.URL.Path)
+        if len(matches) > 0 {
+            if !slices.Contains(rt.methods, r.Method) {
+                w.Header().Set("Allow", r.Method)
+                http.Error(
+                    w, "405 method not allowed", http.StatusMethodNotAllowed,
+                )
+                fmt.Println(r.Method, r.URL.Path)
+            }
+            rt.handler(w, r.WithContext(
+                context.WithValue(r.Context(), URLParam{}, matches[1:])),
+            )
+            return
+        }
+    }
+    http.NotFound(w, r)
+}