ESP8266 Community Forum

- Fri Jan 25, 2019 8:12 am #80267 This is on an ESP32 but I am hoping that as they are much the same libraries I might find some help here.

I am sending a GET and try to read the headers and use http.headers() and get zero as the response.

I can use the http.getSize() and it works and gets the correct size from the "Content-Length" header.

I am trying to get a "Content-MD5" header as I'm downloading a firmware file and doing a check before approving the download.

I am using the WiFiClientSecure to connect to my sever so the download is encrypted.

The url going to a .php file on my server and it then transmits the .bin file with the following headers

Code: Select allheader("Content-MD5:" . strtoupper(bin2hex(md5_file($firmware, true))));
header('Content-Description: File Transfer');
header('Content-Type: application/octet-stream');
header('Content-Disposition: attachment; filename='.basename($firmware));
header('Content-Transfer-Encoding: binary');
header('Content-Length: ' . filesize($firmware));

Using Google Chrome in the Network tab I am able to see the Response Headers including the "Content-MD5" so it at least works on chrome but the ESP doesn't see any of them.

Code: Select allconst char * headerKeys[] = {"date", "server"} ;
const size_t numberOfHeaders = 2;
boolean downloadFirmware(String url, String fileName){
  boolean serverConnected = true;
  WiFiClientSecure client; //create new class for downloading the firmware from webserver
  if(serverConnected == true){
    HTTPClient httpsDownload; //create the http client
    if(httpsDownload.begin(client,url)){ //Start the http client useing the secure client class to the requested url
      http.collectHeaders(headerKeys, numberOfHeaders);
     
      int httpCode = httpsDownload.GET(); //start the connection and send the HTTP header 
      Serial.println(httpsDownload.headers());
      if(httpCode >0){
        Serial.printf("[HTTPS] GET... code: %d\n", httpCode);
        if(httpCode == HTTP_CODE_OK){
          int len = httpsDownload.getSize(); //get the size of the file to be downloaded from the headers
          Serial.print("File size: ");
          Serial.println(len);
          for(int i = 0; i< http.headers(); i++){
            Serial.println(http.header(i));
          }
          String headerDate = http.header("date");
          Serial.println(headerDate);
          if(SPIFFS.totalBytes() > len){ //if there is enough space in the spi flash
            File file = SPIFFS.open(fileName, FILE_WRITE); //open the file to be written
            if(file){ //if the file opens
              WiFiClient * stream = &client; // get TCP stream
              uint8_t buff[255] = { 0 }; //create buffer to hold downloaded data
              MD5_CTX md; //needed for the checksum
              MD5 md5; //needed for the checksum
              md5.MD5Init(&md); //setup the md5 hash for the checksum
             
              //While there is still data or data to be send then download it
              while(httpsDownload.connected() && len > 0 || len == -1){
                size_t size = stream->available(); //read the amount of data that is able to be downloaded
                if (size) { //if there is some data to download
                  int c = stream->readBytes(buff, ((size > sizeof(buff)) ? sizeof(buff) : size)); // read up to 1024 bytes
                  file.write(buff,c); //write the data to the file on the SPI flash
                  md5.MD5Update(&md, buff, c); //update the MD5 hash for the checksum
                  //decrement the amount of data downloaded so far from the total size of the file on the server
                  if (len > 0) { len -= c; }
                }
                delay(1); //delay for if no data is available so we wait a little
              }
              file.close(); //close the file so we can use it later
              unsigned char check[16]; //Holds the MD5 Checksum
              md5.MD5Final(check, &md); //finish the calculation for the cheksum
              Serial.print("Checksum: ");
              for(int i=0;i<16;i++){
                Serial.print(check[i],HEX);
              }
              Serial.println();
            }else{
              errorMessage("FS: error opening the file to write firmware");
              return false;
            }
           
          }else{
            errorMessage("FLASH: not enough space on the flash chip");
            return false;
          } 
        }
      }else{
        errorMessage("HTTPS: Error from webserver");
        errorMessage(String(httpCode));
        return false; 
      }
    }else{
      errorMessage("HTTPS: Error connecting to the server for firmware download");
      return false;
    }
    httpsDownload.end(); //close the connection once finished
    return true;
  }
}

Thanks in advance