feat: add SetClientRootCertificate method support clientCAs usage (#826)

Co-authored-by: Vladislav Kakurin <vladislav@kakurin.com>

client.go

@@ -915,6 +915,46 @@ func (c *Client) SetRootCertificateFromString(pemContent string) *Client {
 	return c
 }
 
+// SetClientRootCertificate method helps to add one or more client's root certificates into Resty client
+//
+//	client.SetClientRootCertificate("/path/to/root/pemFile.pem")
+func (c *Client) SetClientRootCertificate(pemFilePath string) *Client {
+	rootPemData, err := os.ReadFile(pemFilePath)
+	if err != nil {
+		c.log.Errorf("%v", err)
+		return c
+	}
+
+	config, err := c.tlsConfig()
+	if err != nil {
+		c.log.Errorf("%v", err)
+		return c
+	}
+	if config.ClientCAs == nil {
+		config.ClientCAs = x509.NewCertPool()
+	}
+
+	config.ClientCAs.AppendCertsFromPEM(rootPemData)
+	return c
+}
+
+// SetClientRootCertificateFromString method helps to add one or more client's root certificates into Resty client
+//
+//	client.SetClientRootCertificateFromString("pem file content")
+func (c *Client) SetClientRootCertificateFromString(pemContent string) *Client {
+	config, err := c.tlsConfig()
+	if err != nil {
+		c.log.Errorf("%v", err)
+		return c
+	}
+	if config.ClientCAs == nil {
+		config.ClientCAs = x509.NewCertPool()
+	}
+
+	config.ClientCAs.AppendCertsFromPEM([]byte(pemContent))
+	return c
+}
+
 // SetOutputDirectory method sets output directory for saving HTTP response into file.
 // If the output directory not exists then resty creates one. This setting is optional one,
 // if you're planning using absolute path in `Request.SetOutput` and can used together.

client_test.go

@@ -309,6 +309,56 @@ func TestClientSetRootCertificateFromStringErrorTls(t *testing.T) {
 	assertNil(t, transport)
 }
 
+func TestClientSetClientRootCertificate(t *testing.T) {
+	client := dc()
+	client.SetClientRootCertificate(filepath.Join(getTestDataPath(), "sample-root.pem"))
+
+	transport, err := client.Transport()
+
+	assertNil(t, err)
+	assertNotNil(t, transport.TLSClientConfig.ClientCAs)
+}
+
+func TestClientSetClientRootCertificateNotExists(t *testing.T) {
+	client := dc()
+	client.SetClientRootCertificate(filepath.Join(getTestDataPath(), "not-exists-sample-root.pem"))
+
+	transport, err := client.Transport()
+
+	assertNil(t, err)
+	assertNil(t, transport.TLSClientConfig)
+}
+
+func TestClientSetClientRootCertificateFromString(t *testing.T) {
+	client := dc()
+	rootPemData, err := os.ReadFile(filepath.Join(getTestDataPath(), "sample-root.pem"))
+	assertNil(t, err)
+
+	client.SetClientRootCertificateFromString(string(rootPemData))
+
+	transport, err := client.Transport()
+
+	assertNil(t, err)
+	assertNotNil(t, transport.TLSClientConfig.ClientCAs)
+}
+
+func TestClientSetClientRootCertificateFromStringErrorTls(t *testing.T) {
+	client := NewWithClient(&http.Client{})
+	client.outputLogTo(io.Discard)
+
+	rootPemData, err := os.ReadFile(filepath.Join(getTestDataPath(), "sample-root.pem"))
+	assertNil(t, err)
+	rt := &CustomRoundTripper{}
+	client.SetTransport(rt)
+	transport, err := client.Transport()
+
+	client.SetClientRootCertificateFromString(string(rootPemData))
+
+	assertNotNil(t, rt)
+	assertNotNil(t, err)
+	assertNil(t, transport)
+}
+
 func TestClientOnBeforeRequestModification(t *testing.T) {
 	tc := dc()
 	tc.OnBeforeRequest(func(c *Client, r *Request) error {