I am trying to send camera images from my ESP32 (M5 Stack PoECAM) to my personal google drive.

following this tutorial :
https://hobby-it.com/m5timer_gdrive-2/

I have setup SSLClient with the EthernetLarge library the jpgs arrive and but they are corrupted/incomplete. Any ideas why this might be happening, I have tried different chunk sizes no effect ?

I don't believe its hardware as the example sketches all work as intended

errors/warnings

SSLClient)(SSL_WARN)(connected): Socket was dropped unexpectedly (this can be an alternative to closing the connection)

(SSLClient)(SSL_ERROR)(m_print_ssl_error): SSL_CLIENT_WRITE_FAIL
(SSLClient)(SSL_ERROR)(available): Cannot operate if the write error is not reset:

The project is on github (https://gitlab.com/ArchNemsys/esp32-poe-cam) the code for the relevant function (sensitive data removed) is posted below apologies I was halfway through refactoring it to use char bufs rather than strings:

#include <SSLClient.h>
#include "gdrive_trust.h"


#define WRITE_SIZE_MAX   1024 //


//#define API_PORT    443
//#define API_PATH_TOKEN   "/oauth2/v4/token"


const char* refreshServer = "oauth2.googleapis.com";
const char* refreshUri    = "/token";
const char* apiServer     = "www.googleapis.com";
const char* apiUri        = "/upload/drive/v3/files?uploadType=multipart";
char accessToken[2048];   

// ethClient is declared elsewhere but works perfectly outside this funciton
SSLClient httpsClient(ethClient, gdriveTAs, 1, 25);
//  SSLClient::write, is buffered does not actually write to the network. you must call SSLClient::available or SSLClient::flush, 


int waitingTime      = 10000; // Wait 10 seconds to google response.


// Send JPEG by Http POST
void postGoogleDriveByAPI() {
  Serial.println("Connect to " + String(apiServer));
  if (httpsClient.connect(apiServer, 443)) {
    Serial.println("Connection successful");

    // Get Time for save file name
    struct tm timeinfo;
    if(!getLocalTime(&timeinfo)){
      Serial.println("Failed to obtain time 1");
      return;
    } 
    char saveFilename[64];

    /*
    char metadata[256];

    const char* startBoundry = "--foo_bar_baz\r\n"
                      "Content-Type:image/jpeg\r\n\r\n";
    const char* endBoundry = "\r\n--foo_bar_baz--";
    */

    strftime (saveFilename,64,"ALERT_%A_%B_%d_%Y_%Hh%Mm%Ss.jpg",&timeinfo);

    Serial.println(saveFilename);


    /*
    snprintf( metadata, 256, "--foo_bar_baz\r\n"
                      "Content-Type: application/json; charset=UTF-8\r\n\r\n"
                      "{\"name\":\"%s\",\"parents\":[\"%s\"]}\r\n\r\n" , saveFilename, PARENT_ID ); 
    
    unsigned long contentsLength = strlen(metadata) + strlen(startBoundry) + fb->len + strlen(endBoundry);

    snprintf(header,256, "POST %s HTTP/1.1\r\n" 
                    "HOST: %s \r\n" 
                    "Connection: close\r\n" 
                    "content-type: multipart/related; boundary=foo_bar_baz\r\n" 
                    "content-length: %u \r\n" 
                    "authorization: Bearer %s \r\n\r\n", apiUri, apiServer, contentsLength, accessToken);
    */

    String metadata = "--foo_bar_baz\r\n"
                      "Content-Type: application/json; charset=UTF-8\r\n\r\n"
                      "{\"name\":\"" + String(saveFilename) + "\",\"parents\":[\"" + String(PARENT_ID) + "\"]}\r\n\r\n"; // parents:save folder
                      //"{\"name\":\"" + saveFilename + "\"}\r\n\r\n"; // parerents is Optional
    String startBoundry = "--foo_bar_baz\r\n"
                          "Content-Type:image/jpeg\r\n\r\n";
    String endBoundry   = "\r\n--foo_bar_baz--";

    unsigned long contentsLength = metadata.length() + startBoundry.length() + fb->len + endBoundry.length();
    String header = "POST " + String(apiUri) + " HTTP/1.1\r\n" +
                    "HOST: " + String(apiServer) + "\r\n" +
                    "Connection: close\r\n" +
                    "content-type: multipart/related; boundary=foo_bar_baz\r\n" +
                    "content-length: " + String(contentsLength) + "\r\n" +
                    "authorization: Bearer " + accessToken + "\r\n\r\n";
    
    Serial.println("Send JPEG DATA by API");
    httpsClient.print(header);
    httpsClient.print(metadata);
    httpsClient.print(startBoundry);
    // JPEG data is separated into 1000 bytes and POST


    int chunk = 1000;
    unsigned long dataLength = fb->len;
    uint8_t*      bufAddr    = fb->buf;
    for(unsigned long i = 0; i < dataLength ;i=i+chunk) {

      if ( (i + chunk) < dataLength ) {
        httpsClient.write(( bufAddr + i ), chunk);
      } else if (dataLength%chunk != 0) {
        httpsClient.write(( bufAddr + i ), dataLength%chunk);
      }
    }
    httpsClient.print(endBoundry);

    Serial.println("Waiting for response.");
    long int StartTime=millis();
    while (!httpsClient.available()) {
      Serial.print(".");
      delay(100);
      if ((StartTime+waitingTime) < millis()) {
        Serial.println();
        Serial.println("No response.");
        break;
      }
    }

  } else {
    Serial.println("Connected to " + String(refreshServer) + " failed.");
  }

  httpsClient.stop();
}