Initialize Clash Web source and deployment documentation

internal/app/subscription_errors_test.go

@@ -0,0 +1,35 @@
+package app
+
+import (
+	"context"
+	"crypto/x509"
+	"net"
+	"net/url"
+	"strings"
+	"syscall"
+	"testing"
+)
+
+func TestSubscriptionDownloadErrorsExplainCauseWithoutURL(t *testing.T) {
+	for _, test := range []struct {
+		err    error
+		phrase string
+	}{
+		{x509.UnknownAuthorityError{}, "CA 证书包"},
+		{x509.HostnameError{}, "域名不匹配"},
+		{x509.CertificateInvalidError{}, "证书校验失败"},
+		{&net.DNSError{Err: "no such host", Name: "private.example"}, "域名解析失败"},
+		{context.DeadlineExceeded, "下载超时"},
+		{context.Canceled, "已取消"},
+		{syscall.ECONNREFUSED, "连接被拒绝"},
+	} {
+		wrapped := &url.Error{Op: "Get", URL: "https://private.example/sub?token=secret-token", Err: test.err}
+		message := subscriptionDownloadError(wrapped).Error()
+		if !strings.Contains(message, test.phrase) {
+			t.Fatalf("cause not explained: %s", message)
+		}
+		if strings.Contains(message, "secret-token") || strings.Contains(message, "private.example") {
+			t.Fatal("download error exposed subscription URL")
+		}
+	}
+}