feat: hCaptcha middleware

internal/net/gphttp/middleware/captcha/middleware.go

@@ -0,0 +1,61 @@
+package captcha
+
+import (
+	"net/http"
+	"text/template"
+
+	"github.com/yusing/go-proxy/internal/auth"
+	"github.com/yusing/go-proxy/internal/logging"
+	"github.com/yusing/go-proxy/internal/net/gphttp"
+
+	_ "embed"
+)
+
+const cookieName = "godoxy_captcha_session"
+
+//go:embed captcha.html
+var captchaPageHTML string
+var captchaPage = template.Must(template.New("captcha").Parse(captchaPageHTML))
+
+func PreRequest(p Provider, w http.ResponseWriter, r *http.Request) (proceed bool) {
+	// check session
+	sessionID, err := r.Cookie(cookieName)
+	if err == nil {
+		session, ok := CaptchaSessions.Load(sessionID.Value)
+		if ok {
+			if session.expired() {
+				CaptchaSessions.Delete(sessionID.Value)
+			} else {
+				return true
+			}
+		}
+	}
+
+	if !gphttp.GetAccept(r.Header).AcceptHTML() {
+		gphttp.Forbidden(w, "Captcha is required")
+		return false
+	}
+
+	if r.Method == http.MethodPost {
+		err := p.Verify(r)
+		if err == nil {
+			session := newCaptchaSession(p)
+			CaptchaSessions.Store(session.ID, session)
+			auth.SetTokenCookie(w, r, cookieName, session.ID, p.SessionExpiry())
+			http.Redirect(w, r, r.URL.Path, http.StatusFound)
+			return false
+		}
+		gphttp.Unauthorized(w, err.Error())
+		return false
+	}
+
+	// captcha challenge
+	err = captchaPage.Execute(w, map[string]any{
+		"ScriptHTML": p.ScriptHTML(),
+		"FormHTML":   p.FormHTML(),
+	})
+	if err != nil {
+		logging.Error().Err(err).Msg("failed to execute captcha page")
+	}
+	return false
+}