ArduinoHTTPClient POST multipart/form-data from SD card returning 400 Bad Request

Question

I have been having trouble trying to send a small txt file to my server using the following function with TinyGSM. I know I am connected to the internet and reaching the web server, however, I keep receiving a 400 Bad Request code. I think something is wrong with my PostHeader, but I have no clue where or what it could be... I know I am connecting to my server as I try a default get and return webpage text...

TinyGsm modem(SerialAT);
TinyGsmClient client2(modem);
HttpClient client(client2, server, port);

void fileUpload(String filename){
  if(!initSD()){
    return;
  }
  File dataFile = SD.open(filename.c_str());
  Serial.println("Uploading File...");
  if (!client.connect(server, port)) {
    Serial.println("Failed connecting to Server");
    return;
  }
  String fileType = "text/plain";
  String content = "--boundary1\r\n";
  content += "Content-Disposition: form-data; name=\"fileToUpload\"; filename="+String(filename)+"\r\n";  // the fileToUpload is the form parameter
  content += "Content-Type: "+fileType+"\r\n\r\n";
  //after this, post the file data.
  String closingContent = "\r\n--boundary1--";
  //Serial.println(content);
  client.println(String("POST ") + "/upload.php" +" HTTP/1.1\r\n");
  client.println(String("Host: ") + server + "\r\n");
  client.println("Content-Type: multipart/form-data; boundary=boundary1\r\n");
  client.println("Connection: close\r\n");
  client.println("Content-Length: "+String(content.length()+dataFile.size()+closingContent.length())+"\r\n");
  client.println(content);
  client.println();
  if (dataFile) {  // start sending file content 
    while (dataFile.available()) {
      char c = dataFile.read();
        client.print(c);
      }     
    dataFile.close();
  }
  client.println(closingContent);
  Serial.println("File Sent.");
    // read the status code and body of the response
  int statusCode = client.responseStatusCode();
  String response = client.responseBody();

  Serial.print("Status code: ");
  Serial.println(statusCode);
  Serial.print("Response: ");
  Serial.println(response);
}

Answer 1

There were a couple issues that I finally managed to solve... I was able to get it to work by not using ArduinoHTTPClient. Here is working code for anyone else who stumbles here.

TinyGsmClient client(modem);

void fileUpload(String filename){
  File dataFile = SD.open(filename.c_str());
  Serial.println("Uploading File...");
  if (!client.connect(server, port)) {
    Serial.println("Failed connecting to Server");
    return;
  }
  String fileType = "text/plain";
  String content = "--boundary1\r\n";
  content += "Content-Disposition: form-data; name=\"fileToUpload\"; filename="+String(filename)+"\r\n";  // the fileToUpload is the form parameter
  content += "Content-Type: "+fileType+"\r\n\r\n";
  //after this, post the file data.
  String closingContent = "\r\n--boundary1--\r\n";
  //Serial.println(content);
  client.println(String("POST ") + "/upload.php" +" HTTP/1.1"); // or wherever you need to call/print to.
  client.println(String("Host: ") + server);
  client.println("Content-Length: "+String(content.length()+dataFile.size()+closingContent.length()));
  client.println("Content-Type: multipart/form-data; boundary=boundary1");
  client.println();
  client.println(content);
  if (dataFile) {  // start sending file content
    String data = ""; 
    while (dataFile.available()) {
      char c = dataFile.read();
      data += c;
      //write every line break...
      if(c == '\n'){
        client.write(data.c_str());
        data = "";
      }
    }     
    dataFile.close();
  }
  client.print(closingContent);
  unsigned long timeout = millis();
  while (client.connected() && millis() - timeout < 50000L) {
    // Print available data
    while (client.available()) {
      char c = client.read();
      Serial.print(c);
      timeout = millis();
    }
  }
  client.stop();
}