Add header access using same method as arguments 2

based on @brianensor PR
+sample and some sanity check

libraries/ESP8266WebServer/src/ESP8266WebServer.cpp

@@ -37,10 +37,15 @@ ESP8266WebServer::ESP8266WebServer(int port)
 , _lastHandler(0)
 , _currentArgCount(0)
 , _currentArgs(0)
+,_headerKeysCount(0)
+,_currentHeaders(0)
 {
 }
 
 ESP8266WebServer::~ESP8266WebServer() {
+   if (_currentHeaders)
+     delete[]_currentHeaders;
+  _headerKeysCount = 0;
   if (!_firstHandler)
     return;
   RequestHandler* handler = _firstHandler;
@@ -283,6 +288,48 @@ bool ESP8266WebServer::hasArg(const char* name) {
   return false;
 }
 
+String ESP8266WebServer::header(const char* name) {
+  for (int i = 0; i < _headerKeysCount; ++i) {
+    if (_currentHeaders[i].key == name)
+      return _currentHeaders[i].value;
+  }
+  return String();
+}
+
+void ESP8266WebServer::collectHeaders(const char* headerKeys[], const size_t headerKeysCount) {
+  _headerKeysCount = headerKeysCount;
+  if (_currentHeaders)
+     delete[]_currentHeaders;
+  _currentHeaders = new RequestArgument[_headerKeysCount];
+  for (int i = 0; i < _headerKeysCount; i++){
+    _currentHeaders[i].key = headerKeys[i];
+  }
+}
+
+String ESP8266WebServer::header(int i) {
+  if (i < _headerKeysCount)
+    return _currentHeaders[i].value;
+  return String();
+}
+
+String ESP8266WebServer::headerName(int i) {
+  if (i < _headerKeysCount)
+    return _currentHeaders[i].key;
+  return String();
+}
+
+int ESP8266WebServer::headers() {
+  return _headerKeysCount;
+}
+
+bool ESP8266WebServer::hasHeader(const char* name) {
+  for (int i = 0; i < _headerKeysCount; ++i) {
+    if ((_currentHeaders[i].key == name) &&  (_currentHeaders[i].value.length() > 0))
+      return true;
+  }
+  return false;
+}
+
 String ESP8266WebServer::hostHeader() {
   return _hostHeader;
 }

libraries/ESP8266WebServer/src/ESP8266WebServer.h

@@ -83,6 +83,12 @@ public:
   String argName(int i);          // get request argument name by number
   int args();                     // get arguments count
   bool hasArg(const char* name);  // check if argument exists
+  void collectHeaders(const char* headerKeys[], const size_t headerKeysCount); // set the request headers to collect
+  String header(const char* name);   // get request header value by name
+  String header(int i);              // get request header value by number
+  String headerName(int i);          // get request header name by number
+  int headers();                     // get header count
+  bool hasHeader(const char* name);  // check if header exists
 
   String hostHeader();            // get request host header if available or empty String if not
 
@@ -124,6 +130,7 @@ protected:
   void _uploadWriteByte(uint8_t b);
   uint8_t _uploadReadByte(WiFiClient& client);
   void _prepareHeader(String& response, int code, const char* content_type, size_t contentLength);
+  bool _collectHeader(const char* headerName, const char* headerValue);
 
   struct RequestArgument {
     String key;
@@ -140,6 +147,8 @@ protected:
   RequestArgument* _currentArgs;
   HTTPUpload       _currentUpload;
 
+  RequestArgument* _currentHeaders;
+  size_t           _headerKeysCount;
   size_t           _contentLength;
   String           _responseHeaders;
 

libraries/ESP8266WebServer/src/Parsing.cpp

@@ -31,6 +31,10 @@ bool ESP8266WebServer::_parseRequest(WiFiClient& client) {
   // Read the first line of HTTP request
   String req = client.readStringUntil('\r');
   client.readStringUntil('\n');
+  //reset header value
+  for (int i = 0; i < _headerKeysCount; ++i) {
+    _currentHeaders[i].value =String();
+   }
 
   // First line of HTTP request looks like "GET /path HTTP/1.1"
   // Retrieve the "/path" part by finding the spaces
@@ -96,6 +100,7 @@ bool ESP8266WebServer::_parseRequest(WiFiClient& client) {
       }
       headerName = req.substring(0, headerDiv);
       headerValue = req.substring(headerDiv + 2);
+       _collectHeader(headerName.c_str(),headerValue.c_str());
 	  
 	  #ifdef DEBUG
 	  DEBUG_OUTPUT.print("headerName: ");
@@ -161,6 +166,7 @@ bool ESP8266WebServer::_parseRequest(WiFiClient& client) {
       }
       headerName = req.substring(0, headerDiv);
       headerValue = req.substring(headerDiv + 2);
+      _collectHeader(headerName.c_str(),headerValue.c_str());
 	  
 	  #ifdef DEBUG
 	  DEBUG_OUTPUT.print("headerName: ");
@@ -187,6 +193,15 @@ bool ESP8266WebServer::_parseRequest(WiFiClient& client) {
   return true;
 }
 
+bool ESP8266WebServer::_collectHeader(const char* headerName, const char* headerValue) {
+  for (size_t i = 0; i < _headerKeysCount; i++) {
+    if (_currentHeaders[i].key==headerName) {
+            _currentHeaders[i].value=headerValue;
+            return true;
+        }
+  }
+  return false;
+}
 
 void ESP8266WebServer::_parseArguments(String data) {
 #ifdef DEBUG