So gehts mit Wlan und Http Client:
Code:
#include <iostream>

#include "mbed.h"
#include "wifi.h"
/*------------------------------------------------------------------------------
Hyperterminal settings: 115200 bauds, 8-bit data, no parity
 
This example 
  - connects to a wifi network (SSID & PWD)
  - displays the IP address and get webpage html code
 
This example uses SPI3 ( PE_0 PC_10 PC_12 PC_11), wifi_wakeup pin (PB_13), 
wifi_dataready pin (PE_1), wifi reset pin (PE_8)
------------------------------------------------------------------------------*/

#define MBED_CONF_APP_WIFI_SSID     "xyz"
#define MBED_CONF_APP_WIFI_PASSWORD "geheim" 

Serial pc (SERIAL_TX, SERIAL_RX);

DigitalOut led(LED2);
AnalogIn adc_temp(ADC_TEMP);

//
// WLAN mit dem Hotspot verbinden.
//
int wifi_sample_run(void)
{
  uint8_t  IP_Addr[4];
  uint8_t  MAC_Addr[6];

// WLAN initialisieren
  if (WIFI_Init() ==  WIFI_STATUS_OK)
  {
    std::cout << "WiFi initialisieren." << std::endl;

    if (WIFI_GetMAC_Address(MAC_Addr) == WIFI_STATUS_OK)
    {
      std::cout << "Wifi Modul MAC Address: ";
      std::cout << unsigned (MAC_Addr[0]) << ":";
      std::cout << unsigned (MAC_Addr[1]) << ":";
      std::cout << unsigned (MAC_Addr[2]) << ":";
      std::cout << unsigned (MAC_Addr[3]) << ":";
      std::cout << unsigned (MAC_Addr[4]) << ":";
      std::cout << unsigned (MAC_Addr[5]) << std::endl;
    }
    else
    {
      std::cout << "ERROR: MAC-Adresse konnte nicht gelesen werden." << std::endl;
    }

    if (WIFI_Connect (MBED_CONF_APP_WIFI_SSID, MBED_CONF_APP_WIFI_PASSWORD, WIFI_ECN_WPA2_PSK) == WIFI_STATUS_OK)
    {
      std::cout << "WiFi Modul mit Hotspot verbunden." << std::endl;

      if(WIFI_GetIP_Address(IP_Addr) == WIFI_STATUS_OK)
      {
        std::cout << "WiFi Modul IP-Adresse: ";
        std::cout << unsigned (IP_Addr[0]) << ".";
        std::cout << unsigned (IP_Addr[1]) << ".";
        std::cout << unsigned (IP_Addr[2]) << ".";
        std::cout << unsigned (IP_Addr[3]) << std::endl;
      }
      else
      {
        std::cout << "ERROR: WiFi Modul IP-Adresse konnte nicht gelesen werden." << std::endl;
        return -1;
      }
    }
    else
    {
      std::cout << "ERROR: WiFi Modul konnte nicht verbunden werden." << std::endl;
      return -1;
    }
  }
  else
  {
    std::cout << "ERROR: WiFi Modul konnte nicht initialisiert werden" << std::endl;
    return -1;
  }
  return 0;
}

//
// Sende einen HTTP Get an den Server und lese die Server Antwort.
//
void WebClient (void)
{
// Parameter zu welchem Server verbunden werden soll.
  uint16_t      iPort      = 80;
  uint16_t      iLocalPort = 3000;
  uint8_t       ipAddr[4]  = { 10, 0, 0, 3 }; // Muss man mit der Server IP ersetzen.

// Mit dem Serve verbinden.
  WIFI_Status_t wifiRc;
  int32_t       Socket = 0;
  wifiRc = WIFI_OpenClientConnection (Socket, WIFI_TCP_PROTOCOL, "Name", ipAddr, iPort, iLocalPort);

  if (wifiRc != WIFI_STATUS_OK)
  {
    if (wifiRc == ES_WIFI_STATUS_ERROR)
      std::cout << "Connect zum HTTP-Server Fehler: ES_WIFI_STATUS_ERROR" << std::endl;

    std::cout << "Conntect zum HTTP-Server fehlgeschlagen" << std::endl;
    exit (0);
  }
  else
    std::cout << "HTTP-Client Connect erfolgreich ..." << std::endl;

// Sende HTTP Request
  static uint8_t http[1024];
  strcpy ((char *) http, (char *) "GET / HTTP/1.1\r\n");
  strcat ((char *) http, (char *) "Host: domain.de\r\n");
  strcat ((char *) http, (char *) "\r\n");

  uint16_t SentDataLength;
  const int wifiWriteTimeout = 10000;
  wifiRc = WIFI_SendData(0, (uint8_t *)http, strlen((char *)http), &SentDataLength, wifiWriteTimeout);

  if ((wifiRc == WIFI_STATUS_OK) && (SentDataLength != strlen((char *)http)))
  {
    std::cout << "HTTP Request senden fehlgeschlagen" << std::endl;
    wifiRc = WIFI_STATUS_ERROR;
    exit (0);
  }
  else
    std::cout << "HTTP Request '" << http << "' gesendet: " << SentDataLength << std::endl;

// Empfange Server Antwort
  static uint8_t  resp[1024];
         uint16_t respLen;
  const  int      wifiReadTimeout  = 10000;
  WIFI_ReceiveData (Socket, resp, 1200, &respLen, wifiReadTimeout);

  if( respLen > 0)
  {
    std::cout << "HTTP-Client Server Antwort: " << resp << std::endl;
  }
  else
  {
    std::cout << "HTTP-Client: Server Antwort konnte nicht Empfangen werden." << std::endl;
  }
}


int main()
{
  int ret = 0;
  led = 0;
  pc.baud(115200);

  std::cout << "Programm gestartet ..." << std::endl;

// Verbindung zum WLAN Hotspot herstellem
  std::cout << "WLAN: connect" << std::endl;
  ret = wifi_sample_run();

  if (ret != 0)
  {
    std::cout << "WLAN: connect fehlgeschlagen" << std::endl;
    return -1;
  }

  WebClient ();
}
Die platformio Ini ist wie oben angegeben.
Ich habe dazu das Paket benutzt:
Code:
# Lib: DISCO_L475VG_IOT01A_wifi installieren
# ID : 3438
pio lib install 3438