Add post-auth landing page with cookie-based profile storage

main.go

@@ -2,6 +2,7 @@ package main
 
 import (
 	"context"
+	"encoding/base64"
 	"encoding/json"
 	"html/template"
 	"log"
@@ -35,6 +36,11 @@ func handleStatic(w http.ResponseWriter, r *http.Request) {
 
 	name := strings.TrimPrefix(path, "/")
 
+	if name == "index.html" && getProfile(r) != nil {
+		http.Redirect(w, r, "/home.html", http.StatusSeeOther)
+		return
+	}
+
 	if strings.HasSuffix(name, ".html") {
 		t := templates.Lookup(name)
 		if t == nil {
@@ -42,13 +48,20 @@ func handleStatic(w http.ResponseWriter, r *http.Request) {
 			return
 		}
 		w.Header().Set("Content-Type", "text/html")
-		t.Execute(w, envMap())
+		t.Execute(w, templateData(r))
 		return
 	}
 
 	http.ServeFile(w, r, filepath.Join("static", name))
 }
 
+func templateData(r *http.Request) map[string]any {
+	return map[string]any{
+		"env":     envMap(),
+		"profile": getProfile(r),
+	}
+}
+
 func envMap() map[string]string {
 	m := map[string]string{}
 	for _, e := range os.Environ() {
@@ -59,6 +72,33 @@ func envMap() map[string]string {
 	return m
 }
 
+func getProfile(r *http.Request) map[string]any {
+	cookie, err := r.Cookie("profile")
+	if err != nil {
+		return nil
+	}
+	data, err := base64.RawURLEncoding.DecodeString(cookie.Value)
+	if err != nil {
+		return nil
+	}
+	var profile map[string]any
+	if json.Unmarshal(data, &profile) != nil {
+		return nil
+	}
+	return profile
+}
+
+func setProfile(w http.ResponseWriter, profile map[string]any) {
+	data, _ := json.Marshal(profile)
+	http.SetCookie(w, &http.Cookie{
+		Name:     "profile",
+		Value:    base64.RawURLEncoding.EncodeToString(data),
+		Path:     "/",
+		HttpOnly: true,
+		SameSite: http.SameSiteLaxMode,
+	})
+}
+
 func handleGoogleCallback(w http.ResponseWriter, r *http.Request) {
 	if r.Method != http.MethodPost {
 		http.Error(w, "method not allowed", http.StatusMethodNotAllowed)
@@ -78,12 +118,12 @@ func handleGoogleCallback(w http.ResponseWriter, r *http.Request) {
 		return
 	}
 
-	response := map[string]any{
+	profile := map[string]any{
 		"email":   payload.Claims["email"],
 		"name":    payload.Claims["name"],
 		"picture": payload.Claims["picture"],
 	}
 
-	w.Header().Set("Content-Type", "application/json")
-	json.NewEncoder(w).Encode(response)
+	setProfile(w, profile)
+	http.Redirect(w, r, "/home.html", http.StatusSeeOther)
 }