I get this error when I try to upload an image through a SOAP webservice using the nusoap php library. I have very little experience with php and SOAP therefore I would appreciate any help. I share my code:

server.php

require_once('lib/nusoap.php'); //include required class for build nnusoap web service server

// Create server object
$server = new soap_server();

// configure  WSDL
$server->configureWSDL('Upload File', 'urn:uploadwsdl');

// Register the method to expose
$server->register('upload_file',                                 // method
    array('file' => 'xsd:string','location' => 'xsd:string'),    // input parameters
    array('return' => 'xsd:string'),                             // output parameters
    'urn:uploadwsdl',                                            // namespace
    'urn:uploadwsdl#upload_file',                                // soapaction
    'rpc',                                                       // style
    'encoded',                                                   // use
    'Uploads files to the server'                                // documentation
);

// Define the method as a PHP function

function upload_file($encoded,$name) {
    $location = "uploads\".$name;                               // Mention where to upload the file
    $current = file_get_contents($location);                     // Get the file content. This will create an empty file if the file does not exist     
    $current = base64_decode($encoded);                          // Now decode the content which was sent by the client     
    file_put_contents($location, $current);                      // Write the decoded content in the file mentioned at particular location      
    if($name!="")
    {
        return "File Uploaded successfully...";                      // Output success message                              
    }
    else        
    {
        return "Please upload a file...";
    }
}

// Use the request to (try to) invoke the service
$HTTP_RAW_POST_DATA = isset($HTTP_RAW_POST_DATA) ? $HTTP_RAW_POST_DATA : '';
$server->service($HTTP_RAW_POST_DATA); 

client.php

require_once('lib/nusoap.php'); //include required class for build nnusoap web service server
$wsdl="http://{servidor}/WebServiceSOAP/server.php?wsdl";  // SOAP Server

if($_POST["submit"])
{
   $tmpfile = $_FILES["uploadfiles"]["tmp_name"];   // temp filename
   $filename = $_FILES["uploadfiles"]["name"];      // Original filename

   $handle = fopen($tmpfile, "r");                  // Open the temp file
   $contents = fread($handle, filesize($tmpfile));  // Read the temp file
   fclose($handle);                                 // Close the temp file

   $client=new soapclient($wsdl) or die("Error");   // Connect the SOAP server
   $response = $client->_call('upload_file',array($filename)) or die("Error");  //Send two inputs strings. {1} DECODED CONTENT {2} FILENAME
}   

//$client=new soapclient($wsdl) or die("Error");   // Connect the SOAP server
//$response = $client->__call('upload_file',array($decodeContent,$filename)) or die("Error");  //Send two inputs strings. {1} DECODED CONTENT {2} FILENAME

// Check if there is anny fault with Client connecting to Server
if($client->fault){
    echo "Fault {$client->faultcode} <br/>";
    echo "String {$client->faultstring} <br/>";
}
else{
    print_r($response); // If success then print response coming from SOAP Server
}
<form name="name1" method="post" action="" enctype="multipart/form-data">
  <input type="file" name="uploadfiles"><br />
  <input type="submit" name="submit" value="uploadSubmit"><br />
</form>

I get the error when I press the button to upload the image. This is the log that I get:

error_log

[14-Apr-2018 22:44:57 America/Chicago] PHP Notice:  Undefined index: submit in /home/XXXX/public_html/WebServiceSOAP/client.php on line 5
[14-Apr-2018 22:44:57 America/Chicago] PHP Notice:  Undefined variable: client in /home/XXXX/public_html/WebServiceSOAP/client.php on line 22
[14-Apr-2018 22:44:57 America/Chicago] PHP Notice:  Trying to get property of non-object in /home/XXXX/public_html/WebServiceSOAP/client.php on line 22
[14-Apr-2018 22:44:57 America/Chicago] PHP Notice:  Undefined variable: response in /home/XXXX/public_html/WebServiceSOAP/client.php on line 27
[14-Apr-2018 22:45:05 America/Chicago] PHP Fatal error:  Call to undefined method soapclient::_call() in /home/XXXX/public_html/WebServiceSOAP/client.php on line 15