Extend HTTPClient to allow connecting with a client certificate (#788)

* Forward client certificate to wificlient secure

* remove comment

libraries/HTTPClient/src/HTTPClient.cpp

@@ -54,8 +54,8 @@ public:
 class TLSTraits : public TransportTraits
 {
 public:
-    TLSTraits(const char* CAcert) :
-        _cacert(CAcert)
+    TLSTraits(const char* CAcert, const char* clicert = nullptr, const char* clikey = nullptr) :
+        _cacert(CAcert), _clicert(clicert), _clikey(clikey)
     {
     }
 
@@ -67,12 +67,16 @@ public:
     bool verify(WiFiClient& client, const char* host) override
     {
          WiFiClientSecure& wcs = static_cast<WiFiClientSecure&>(client);
-		 wcs.setCACert(_cacert);
+         wcs.setCACert(_cacert);
+         wcs.setCertificate(_clicert);
+         wcs.setPrivateKey(_clikey);
          return true;
     }
 
 protected:
     const char* _cacert;
+    const char* _clicert;
+    const char* _clikey;
 };
 
 /**
@@ -203,6 +207,20 @@ bool HTTPClient::begin(String host, uint16_t port, String uri, const char* CAcer
     return true;
 }
 
+bool HTTPClient::begin(String host, uint16_t port, String uri, const char* CAcert, const char* cli_cert, const char* cli_key)
+{
+    clear();
+    _host = host;
+    _port = port;
+    _uri = uri;
+
+    if (strlen(CAcert) == 0) {
+        return false;
+    }
+    _transportTraits = TransportTraitsPtr(new TLSTraits(CAcert, cli_cert, cli_key));
+    return true;
+}
+
 /**
  * end
  * called after the payload is handled

libraries/HTTPClient/src/HTTPClient.h

@@ -129,6 +129,7 @@ public:
     bool begin(String url, const char* CAcert);
     bool begin(String host, uint16_t port, String uri = "/");
     bool begin(String host, uint16_t port, String uri, const char* CAcert);
+    bool begin(String host, uint16_t port, String uri, const char* CAcert, const char* cli_cert, const char* cli_key);
 
     void end(void);