WiFiClientSecure::lastError() method (espressif#945)

* Added a lastError method to WiFiClientSecure so that a connection error from mbedTLS can be retrieved if connection fails (and then presented to a user). * Changed to dos CRLF * Made buffer size a const\nMore cleanup to match source

Author: lbernstone

libraries/WiFiClientSecure/src/WiFiClientSecure.cpp

@@ -103,6 +103,7 @@ int WiFiClientSecure::connect(IPAddress ip, uint16_t port, const char *_CA_cert,
 int WiFiClientSecure::connect(const char *host, uint16_t port, const char *_CA_cert, const char *_cert, const char *_private_key)
 {
  int ret = start_ssl_client(sslclient, host, port, _CA_cert, _cert, _private_key);
+ _lastError = ret;
  if (ret < 0) {
  log_e("lwip_connect_r: %d", errno);
  stop();
@@ -187,3 +188,13 @@ void WiFiClientSecure::setPrivateKey (const char *private_key)
  _private_key = private_key;
 }
 
+int WiFiClientSecure::lastError(char *buf, const size_t size)
+{
+ if (!_lastError) {
+ return 0;
+ }
+ char error_buf[100];
+ mbedtls_strerror(_lastError, error_buf, 100);
+ snprintf(buf, size, "%s", error_buf);
+ return _lastError;
+}

libraries/WiFiClientSecure/src/WiFiClientSecure.h

@@ -29,7 +29,8 @@ class WiFiClientSecure : public WiFiClient
 {
 protected:
  sslclient_context *sslclient;
-
+ 
+ int _lastError = 0;
  const char *_CA_cert;
  const char *_cert;
  const char *_private_key;
@@ -55,7 +56,7 @@ class WiFiClientSecure : public WiFiClient
  void flush() {}
  void stop();
  uint8_t connected();
-
+ int lastError(char *buf, const size_t size);
  void setCACert(const char *rootCA);
  void setCertificate(const char *client_ca);
  void setPrivateKey (const char *private_key);