I try to create a nusoap web service (I use xampp and .net beans) and connect to it using a C# app (use visual studio). but I encounter this error:

{"Server returned an invalid SOAP Fault. Please see InnerException for more details."}

the inner error is:

{"Element 'faultstring' with namespace name '' was not found. Line 6, position 126."}

As this source suggested I changed properties order for function serialize() in class.soap_fault.php file but it still gives the same error.

I tried restarting the computer so I now it is not a catch problem.

Also the only other change I made in nusoap library was changing var $soap_defencoding = 'ISO-8859-1'; to var $soap_defencoding = 'UTF-8'; in nusoap.php file to solve encoding problem.

in C# I have the following code:

SR1.demoPortTypeClient client = new SR1.demoPortTypeClient();
var result = client.gettext("hello");
MessageBox.Show("*" + result + "*");

and in php:

require 'lib/nusoap.php';
$server=new nusoap_server();
$namespace = "demo";
$server->wsdl->schemaTargetNamespace = $namespace;
        "gettext",//name of function
        $namespace,// namespace
        false,// soapaction (use default)
        'rpc',// style: rpc or document
        'encoded',// use: encoded or literal
        'Return same text'// description for method


where gettext function is:

function gettext($txt)
    return $txt;

current serialize() function is:

function serialize(){
        $ns_string = '';
        foreach($this->namespaces as $k => $v){
            $ns_string .= "\n  xmlns:$k=\"$v\"";
        $return_msg =
            '<?xml version="1.0" encoding="'.$this->soap_defencoding.'"?>'.
            '<SOAP-ENV:Envelope SOAP-ENV:encodingStyle="http://schemas.xmlsoap.org/soap/encoding/"'.$ns_string.">\n".
                    $this->serialize_val( $this->faultcode,   'faultcode'   ) .
                            $this->serialize_val( $this->faultstring, 'faultstring' ) .
                            $this->serialize_val( $this->faultactor,  'faultactor'  ) .
                            $this->serialize_val( $this->faultdetail, 'detail'      ) .
        return $return_msg;

I expected changing order of properties solves the problem, however I still receive the same error. I searched a lot but couldn't find any other solve for the error.

1 Answers

Community On Best Solutions

For reason I do not know, there is two definition for function serialize() with same body in two different file. One in class.soap_fault.php and another in nusoap.php and you need to change the method body in the second one (nusoap.php). I do not know is there any condition you need to change other one or not.

For other ones who may reach this post I add some problems you may encounter and their solve:

Exception :

Encodes were different (windows uses 'utf-8' and this uses 'ISO-8859-1')

Reason: Encoding type are different in server and client.

Solve: In nusoap.php file changing var $soap_defencoding = 'ISO-8859-1'; to var $soap_defencoding = 'UTF-8';

See: this source

Exception :

Server returned an invalid SOAP Fault. Please see InnerException for more details


Element ‘faultstring’ with namespace name ” was not found. Line 6, position 126

Reason: Difference in order of fault properties

Solve: in nusoap.php change function serialize() to following:

function serialize() {
      $ns_string = '';
      foreach( $this->namespaces as $k => $v ) {
        $ns_string .= "\n  xmlns:$k=\"$v\"";
      $return_msg =
        '<?xml version="1.0" encoding="' . $this->soap_defencoding . '"?>' .
        '<SOAP-ENV:Envelope SOAP-ENV:encodingStyle="http://schemas.xmlsoap.org/soap/encoding/"' . $ns_string . ">\n" .
          '<SOAP-ENV:Body>' .
            '<SOAP-ENV:Fault>' .
              $this->serialize_val( $this->faultcode,   'faultcode'   ) .
              $this->serialize_val( $this->faultstring, 'faultstring' ) .
              $this->serialize_val( $this->faultactor,  'faultactor'  ) .
              $this->serialize_val( $this->faultdetail, 'detail'      ) .
            '</SOAP-ENV:Fault>' .
          '</SOAP-ENV:Body>' .
      return $return_msg;

See: this source


{"error in msg parsing:\nxml was empty, didn't parse!"}

Reason: The following php function is not valid in current version:

solve: use following code for php version 5.6.0 to before 7.0.0


and for version 7.0.0 and later use:


See: This source


{"method ''('function name here'('function name here') not defined in service('' '')"}

or simply:

method '' not defined in service.

Reason: When using C# to connecting to the nusoap web server. It is disable to find methods defined in other files/classes.

Solve: define all method in the same file as you write web service

See: This source

Note: If you know a way to overcome this problem and let define methods in other files/classes (= make cleaner code) please comment it.


{"Error in deserializing body of reply message for operation 'method name'."}

Reason: May have different reasons but in my case occure when try to use arrays as property for returned structure. C# will see array of string as string.

Solve: I solved it by using basic types.

Note: if you know better way please comment it