Put SSDP constants in progmem (#3142)

* Put constant strings in progmem

* strlen -> strlen_P

Author: sidoh

libraries/ESP8266SSDP/ESP8266SSDP.cpp

@@ -56,16 +56,16 @@ static const IPAddress SSDP_MULTICAST_ADDR(239, 255, 255, 250);
 
 
 
-static const char* _ssdp_response_template =
+static const char _ssdp_response_template[] PROGMEM =
   "HTTP/1.1 200 OK\r\n"
   "EXT:\r\n";
 
-static const char* _ssdp_notify_template =
+static const char _ssdp_notify_template[] PROGMEM =
   "NOTIFY * HTTP/1.1\r\n"
   "HOST: 239.255.255.250:1900\r\n"
   "NTS: ssdp:alive\r\n";
 
-static const char* _ssdp_packet_template =
+static const char _ssdp_packet_template[] PROGMEM =
   "%s" // _ssdp_response_template / _ssdp_notify_template
   "CACHE-CONTROL: max-age=%u\r\n" // SSDP_INTERVAL
   "SERVER: Arduino/1.0 UPNP/1.1 %s/%s\r\n" // _modelName, _modelNumber
@@ -74,7 +74,7 @@ static const char* _ssdp_packet_template =
   "LOCATION: http://%u.%u.%u.%u:%u/%s\r\n" // WiFi.localIP(), _port, _schemaURL
   "\r\n";
 
-static const char* _ssdp_schema_template =
+static const char _ssdp_schema_template[] PROGMEM =
   "HTTP/1.1 200 OK\r\n"
   "Content-Type: text/xml\r\n"
   "Connection: close\r\n"
@@ -201,9 +201,12 @@ void SSDPClass::_send(ssdp_method_t method){
   char buffer[1460];
   uint32_t ip = WiFi.localIP();
 
-  int len = snprintf(buffer, sizeof(buffer),
+  char valueBuffer[strlen_P(_ssdp_notify_template)+1];
+  strcpy_P(valueBuffer, (method == NONE)?_ssdp_response_template:_ssdp_notify_template);
+
+  int len = snprintf_P(buffer, sizeof(buffer),
     _ssdp_packet_template,
-    (method == NONE)?_ssdp_response_template:_ssdp_notify_template,
+    valueBuffer,
     SSDP_INTERVAL,
     _modelName, _modelNumber,
     _uuid,
@@ -240,7 +243,9 @@ void SSDPClass::_send(ssdp_method_t method){
 
 void SSDPClass::schema(WiFiClient client){
   uint32_t ip = WiFi.localIP();
-  client.printf(_ssdp_schema_template,
+  char buffer[strlen_P(_ssdp_schema_template)+1];
+  strcpy_P(buffer, _ssdp_schema_template);
+  client.printf(buffer,
     IP2STR(&ip), _port,
     _deviceType,
     _friendlyName,