Dimuthu’s Blog

In WSF/PHP WDL Mode we have two APIs, first one is the class based API which we give a class object as the input parameter for the operation and expect to retrieve a class object as the response as well. The other API is the array based API. which we give an array (in fact an associated map) containing all the necessary information and returns an array filled with response information.

If you are using WSDL2PHP script you are always using the class based API. But there are situations where you can easily use array based API instead of the class based API. Here is an example.

Take the simple add operation of the following WSDL, http://labs.wso2.org/wsf/php/example.xml.

If you generated the code using wsdlphp tool (Here is the complete generated code for the above wsdl using online wsdlphp tool) You can see two classes are generated for the above operation, one for the input object and the other for the output object.

class simpleAdd {

    /**
     * @var int
     */
    public $param0;

    /**
     * @var int
     */
    public $param1;

}

class simpleAddResponse {

    /**
     * @var int
     */
    public $return;

}

So in order to invoke the service you need to create an object of the simpleAdd and set your input parameters and return the value from the simpleAddResponse object.

  $input = new simpleAdd();

  $input->param0 = 3;
  $input->parma1 = 4;

  // call the operation
  $response = $proxy->simpleAdd($input);

  // extract the return value
  echo $response->return;

But if you are using array mode for the same operation it will be something like this.

  // input as an array
  $input = array("param0" => 3, "param1" => 4);

  // call the operation
  $response = $proxy->simpleAdd($input);

  // extract out the return value from the array
  echo $response["return"];

In this approach you don’t need to declare classes at the start. So you can write the code without the support of WSDL2PHP tool. Anyway for complex scenarios it is not easy to find the keys needed to be in the input array, so it is better depend on the generated code. But you can use array based approach more productively for simple scenarios like this.

In PHP you have several ways of sending binary data. It can be primarily categorized in to non-optimized method (send as base64 binary) and optimized method (send as MTOM or SWA). Here I m talking about how to send binaries in above mentioned methods starting from a WSDL.

WSDL

Think you have a WSDL with the following XML Schema.

            <!-- Here is my submitPerson method->

            <xs:element name="submitPerson">
                <xs:complexType>
                    <xs:sequence>
                        <xs:element name="name" type="xs:string"/>
                        <xs:element name="age" type="xs:int"/>
                        <xs:element name="photo" type="xs:base64Binary"/>
                    </xs:sequence>
                </xs:complexType>
            </xs:element>

The submit Person method submit the name,age and a photo which is a type of base64Binary.

Generated Class

After generating php class for this piece of code using wsdl2php you will have  the following class.

class submitPerson {

    /**
     * @var string
     */
    public $name;

    /**
     * @var int
     */
    public $age;

    // You need to set only one from the following two vars

    /**
     * @var Plain Binary
     */
    public $photo;

    /**
     * @var base64Binary
     */
    public $photo_encoded;

}

So it is very easy to fill the class with your own data. Note that you only need to fill one of the ‘photo’ or ‘photo_encoded’ fields. If you have binary already converted to base64 then you can use the ‘photo_encoded’ field where as if you only have the row binary just use the ‘photo’ field. Here are my values for this particular example.

$person = new submitPerson();
$person->name = "xxxx yyy";
$person->age = 35;
$person->photo = file_get_contents("/photo/xxxyyy");

Sending Binary as MTOM

Here is the code you need to send the above structure as a MTOM message.

$client = new WSClient(array("useMTOM" => TRUE)); // anyway useMTOM is default to TRUE for WSClient
$proxy = $client->getProxy();

$response = $proxy->submitPerson($person);

Sending Binary as Base64 Encoded string

You only need to change one option. That is setting “useMTOM” to FALSE will send the binary as Base64.

$client = new WSClient(array("useMTOM" => FALSE));
$proxy = $client->getProxy();

$response = $proxy->submitPerson($person);

SWA (SOAP With Attachments)
You can send the binary data as SWA by setting the “useMTOM” option to “SWA”. SWA is also a binary optimized method of sending attachments, but unlike with MTOM you can’t integrate security or reliability with this approach.

WSDL2PHP makes the development of web service providers and consumers quick and easy. I wrote a 2 minutes guide on developing web services providers sometimes ago. So lets concentrate on developing web service consumers here.

Where is WSDL2PHP?

WSDL2PHP script is included in the WSF/PHP packs. You can find the wsdl2php.php script inside the ‘scripts’ directory of any source or binary package. Or you can use the online wsd2php tool hosted in WSF/PHP web services DEMO Site.

How to Run the Script?

Here is the command

/scripts/wsdl2php.php mywsdl.wsdl > myclient.php

The Code is Generated. How Can I add My Code There?

It is simple. Just search for the comment “//TODO”.
Check for an example here.

You have to write custom code for 2 occasions per operation.

1. To Provide Input Parameters
2. To Handle output parameters.

An Example?

Here is the code snippet corresponding to the simpleAdd request for our demo WSDL.

    $input = new simpleAdd();
    //TODO: fill in the class fields of $input to match your business logic

    // call the operation
    $response = $proxy->simpleAdd($input);
    //TODO: Implement business logic to consume $response, which is of type simpleAddResponse

Here is how after I filled my logic in place of TODO comments.

    $input = new simpleAdd();
    //DONE: fill in the class fields of $input to match your business logic

    //-------my code----
    $input->param0 = 2;
    $input->param1 = 3;
    //------------------

    // call the operation
    $response = $proxy->simpleAdd($input);
    //DONE: Implement business logic to consume $response, which is of type simpleAddResponse

    //--------my code-----
    echo $response->return;
    //--------------------

In the code first approach, WSF/PHP will generate you the WSDL from your annotated PHP code. If you are familiar with older versions of WSF/PHP you should be already familiar with the syntax used in the annotations which are more or less the same as the conventional PHP doc comment. If you are really new to WSF/PHP annotated code here are two examples.

1. Function with simple types for input and output parameters.

/**
 * add function
 * @param int $x (maps to xsd:int)
 * @param int $y (maps to xsd:int)
 * @return int $x (maps to xsd:int)
 */
 function add($x, $y) {
   return $x + $y;
 }

2. Function with PHP classes for input and output parameters

/**
 * add function
 * @param object Vector $x (maps to objects)
 * @param object Vector $y (maps to objects)
 * @return object Vector $z (maps to objects)
 */
 function add($x, $y) {
   return $x + $y;
 }

 class Vector {
    /**
     * @var array of int $numbers (maps to xs:int)
     */
    public $numbers;
 }

WSF/PHP 2.0 has introduced new PHP annotation syntax so you have more control over the generating WSDL.

• Now you can have custom namespaces for your schemas
• More control over minOccurs and maxOccurs values.
• Supporting ‘In only’ Message Exchange Pattern.
• Generating with WS-Addressing parameters if the ‘useWSA’ option is set to true.
• Fixes for empty input parameters.

So if you prefer Code First approach, WSF/PHP 2.0 will provide you an ideal platform for quick and easy development of web services.

WSDL2Java and WSDL2C tools shipped with the Axis2/Java project are used to generate Stubs(client side) and Skeletons(Server Side) respectively for Axis2/Java and Axis2/C codes. This make the development of web services and consumers more quicker and easier.

The tools come with many options allowing the user to customize the code generation. One of the such option is ‘-uw’ which used to turn on the ‘unwrapping’ mode. WSDL2Java project had this option for a long time, But it is just Today I was able to enable that option in the WSDL2C tool. So lets see how it make the code easier.

Say you have the ‘simpleAdd’ operation with the following schema,

            <xs:element name="simpleAdd">
                <xs:complexType>
                    <xs:sequence>
                        <xs:element minOccurs="0" name="param0" type="xs:int"/>
                        <xs:element minOccurs="0" name="param1" type="xs:int"/>
                    </xs:sequence>
                </xs:complexType>
            </xs:element>
            <xs:element name="simpleAddResponse">
                <xs:complexType>
                    <xs:sequence>
                        <xs:element minOccurs="0" name="return" type="xs:int"/>
                    </xs:sequence>
                </xs:complexType>
            </xs:element>

When you generate the code for server side with Java using the following command, (note the option -uw which stands for ‘unwrapping’)

wsdl2java.sh -uri xxx.wsdl -u -ss -sd -uw

it gives you the following service function.

public int simpleAdd(int param0, int param1)
{
    //TODO : fill this with the necessary business logic
}

Note the input and output parameters of the function are simple types. If you don’t give the ‘-uw’ option, You will instead get a function with input and output variables as class names wrapping these simple types which is not this much straight forward.

So now the same is available with C. You can use WSDl2C tool with the same option set to generate a very simple service API.

wsdl2c.sh -uri xxx.wsdl -u -ss -sd -uw

And here is the service logic you may write, Can you think of an API simpler than this,

        /**
         * auto generated function definition signature
         * for "simpleAdd|http://ws.apache.org/axis2" operation.
         * @param env environment ( mandatory)
         * @param _param0 of the int
         * @param _param1 of the int
         *
         * @return int
         */
        int axis2_skel_UnwrappedAdder_simpleAdd(const axutil_env_t *env,
                                              int _param0,
                                              int _param1 )

        {
          return _param0 + _param1;
        }

You can find the code for complete case (wsdl, skel and stub) in the Axis2/C Jira Attachment space for the ‘unwrapping’ issue. Note that this update is only available in the nightly build and not in the release. You can download the nightly build from wso2′s axis2/java nightly build page.

I have been working for Axis2/C codegen tool for sometime now and I found lot of users who want to edit the codegen templates for a more optimized code specific to their use cases. This is mainly because codegen tool generates a very general code (For an example lot of unused variables generated for some WSDLs, but they are used in some other WSDLs) where as mostly ‘C’ people prefer to be as optimized as possible. Axis2 Java templates are more stable and not needed to customized as much as C templates, but Java developers too may find it is really useful to edit them in a case they need some customizations.

Both Axis2 C and Java tools comes with Axis2/Java project. So you may already have downloaded the latest Axis2/Java release or the Axis2/Java nightly build. As per title you can do this customization not only in the source but also in the binary pack. So I assume you have the binary pack.

Codegen tool mainly comes within two jars inside the lib directory of your Axis2/Java pack. (Here xxxx should be replaced with the particular jar version, it can be 1.4, 1.4.1 or SNAPSHOT)

• axis2-codegen-xxxx.jar – The core classes of the codegen (This is where WSDL2C and WSDL2Java classes reside)
• axis2-adb-codegen-xxxx.jar – This is the library containing the adb component of the codegen tool. ADB (Axis2 Data Binding) is the native databinding format of Axis2 which convert your xml schema to a more programmer friendly set of java classes or ‘C’ structures. The XSD2Java class comes in this jar.

Editing the Stub and Skeleton templates

When you unpack the axis2-codegen-xxxx.jar

jar xf axis2-codegen-xxxx.jar

you can find the template for Stub and Skel in org/apache/axis2/wsdl/template/c or org/apache/axis2/wsdl/template/java directories.

• Stub For C – org/apache/axis2/wsdl/template/c/StubSourceTemplate.xsl (source) and org/apache/axis2/wsdl/template/c/StubHeaderTemplate.xsl (header)
• Skeleton for C – org/apache/axis2/wsdl/template/c/SkelSourceTemplate.xsl (source) and org/apache/axis2/wsdl/template/c/SkelHeaderTemplate.xsl (header)
• Stub For Java – org/apache/axis2/wsdl/template/java/InterfaceImplementationTemplate.xsl
• Skel For Java – org/apache/axis2/wsdl/template/java/MessageReceiverTemplate.xsl (Message Reciever) and org/apache/axis2/wsdl/template/java/SkeletonTemplate.xsl (skeleton)

These templates are written is XSL. Even if you are an XSL expert, you may find little difficult to understand whole lot of codes in there. But if you really know what you need to change, you can track back the lines (may be using comment or some specific static set of code). So you don’t actually need to know any XSL to do these little customizations.

After you do the change simply pack the classes (which are in the ‘org’ directory) as the jar with the same name.

jar cf axis2-codegen-xxxx.jar org

Editing the ADB templates

You can similarly observe the axis2-adb-codegen-xxxx.jar. All the templates are in the org/apache/axis2/schema/template/ directory.

• C ADB templates – org/apache/axis2/schema/template/CADBBeanTemplateHeader.xsl (Source) and org/apache/axis2/schema/template/CADBBeanTemplateHeader.xsl (Header)
• Java ADB template – org/apache/axis2/schema/template/ADBBeanTemplate.xsl

You will find the template for the Java classes and C structures there. In C code generation if you find some variables are not used throughout your WSDLs, you can remove directly if from the templates. And some constants which are defined to allocate memory can be changed to suit to your application.

Anyway after all these notes, I have to say it is not really recommended to hack a code specific to your application. If you found a change general to all the applications you better submit the patch to the Axis2 community, so others too can use it. Otherwise whenever you do a upgrade you have to do this again on your own. But I hope these tips may be useful specially when you are working with ADB to do your own experiments.

WSF/PHP allows you to develop web services with both Contract First (Starting from WSDL) and Code First Approaches. From these two, Contract First approach is the most famous and most recomended way of developing a Webservice. There you need to have a WSDL to start with. I will take the http://labs.wso2.org/wsf/php/example.xml as our WSDL.

Generate The Service Code

When you download the WSF/PHP pack there is a script called ‘wsdl2php.php’ in the script directory. Open a command line and run it with the following options. Or you can use the online wsdl2php tool

php wsdl2php.php http://labs.wso2.org/wsf/php/example.xml -s

Complete The Business Logic

Complete the TODO section of the generated file. Apparently what is left to do is filling the business logic for each function corresponding to the service operations in your WSDL. You are given the hint to the input and output parameters. Here is how I fill the logic for the simpleAdd function.

function simpleAdd($input) {
    // TODO: fill in the business logic
    // NOTE: $input is of type simpleAdd
    // NOTE: should return an object of type simpleAddResponse

    $res = new simpleAddResponse();

    $res->return = $input->param0 + $input->param1;

    return $res;
}

Advanced Types? – Read Generated Hints for Class variables

So how about filling the matrix add logic. Can be it be really complex?. No, what you need to observe is there the class member variables contains not only simple types but also another Class type. There is a comment on each member variables to hint its type. So the logic for the matrix addition is simple as this,

function matrixAdd($input) {
    // TODO: fill in the business logic
    // NOTE: $input is of type matrixAdd
    // NOTE: should return an object of type matrixAddResponse

    $matrix0 = $input->param0;
    $matrix1 = $input->param1;

    $matrix2 = new Matrix();
    $matrix2->rows = array();

    if(count($matrix0->rows) == count($matrix1->rows)) { // considering only happy path

        for($i = 0; $i < count($matrix0->rows); $i ++ ) {

            $row0 = $matrix0->rows[$i];
            $row1 = $matrix1->rows[$i];

            $row2 = new MatrixRow();
            $matrix2->rows[] = $row2;
            $row2->columns = array();

            if(count($row0->columns) == count($row1->columns)) {

                for($j = 0; $j< count($row0->columns); $j ++ ) {

                    $col0 = $row0->columns[$j];
                    $col1 = $row1->columns[$j];

                    $col2 = $col0 + $col1;

                    $row2->columns[] = $col2;
                }
            }
        }
    }

    $res = new matrixAddResponse();
    $res->return = $matrix2;
    return $res;
}

Whenever you deploy a service script in WSF/PHP you can access its WSDL by adding “?wsdl” or “?wsdl2″ (for WSDL version 2.0) to the service endpoint. Anyway you may have noticed that for some services it will just list the operations with xsd:anyType as the input and output message schemes.

For an example for an operation like this,

<?php

function getInvoice($order_no) {
   //something that return an invoice for this order 
}

$operations = array("getInvoice" => "getInvoice");

$svr = new WSService(array("operations" => $operations));

$svr->reply();
?>

This will generate you a nice WSDL but with a schema similar to this,

<xsd:element name="getInvoice">
    <xsd:complexType>
       <xsd:sequence>
           <xsd:element name="order_no" type="xsd:anyType"/>
       </xsd:sequence>
    </xsd:complexType>
</xsd:element>

This schema is not enough for get an understanding about the request, response message formats, because it uses xsd:anyType to represent a general message. In order to get more specific schema, you need to provide more details to the WSDL generator. Here is how it is done using annotations.

<?php
/**
 * @param int $orderNo Order Number
 * (maps to xsd:int)
 * @return string $invoice Invoice as a string
 * (maps to xsd:string)
 */
function getInvoice($order_no) {
   //something that return an invoice for this order 

}

$operations = array("getInvoice" => "getInvoice");
$opParams = array("getInvoice" => "MIXED"); // Have to declare parameters as MIXED

$svr = new WSService(array("operations" => $operations, "opParams" => $opParams));

$svr->reply();
?>

Now check the schema. It will gives you the information specific to your request, response messages.

<xsd:schema elementFormDefault="qualified"
    targetNamespace="http://www.wso2.org/php/xsd">
    <xsd:element name="getInvoice">
        <xsd:complexType>
            <xsd:sequence>
                <xsd:element name="orderNo" type="xsd:int"/>
            </xsd:sequence>
        </xsd:complexType>
    </xsd:element>
    <xsd:element name="getInvoiceResponse">
        <xsd:complexType>
            <xsd:sequence>
                <xsd:element name="invoice" type="xsd:string"/>
            </xsd:sequence>
        </xsd:complexType>
    </xsd:element>
</xsd:schema>

So it is your chance to do more experiment with this feature. Check WSDL generation API for more snippets.

Building and Traversing XML are regular tasks for any Web Service developer. We may use DOM, AXIOM or even simple String manipulation functions to do that. Normally this takes a lot of time and effort. And if we are coding in ‘C’ it become more tedious as string manipulation in ‘C’ is not that straight forward.

What ADB does is it generates a set of ‘C’ functions specially for our XML Schema to build and traverse the XML.
Say you have the following XML Schema. (You need to have it inside a WSDL to generate the code).

        <xs:schema targetNamespace="http://dimuthu.org/adb/demo/2008/sept">
            <!-- demonstrating element-->
            <xs:element name="myDemo">
                <xs:complexType>
                    <xs:sequence>
                        <xs:element name="demo1" type="xs:int"/>
                        <xs:element name="demo2" type="xs:string"/>
                    </xs:sequence>
                </xs:complexType>
            </xs:element>
        <xs:schema/>

For this particular element there will be one adb type (adb_myDemo_t), one source (adb_myDemo.c) and one header (adb_myDemo.h) are generated. Don’t ever look at the source file (unless you want to hack it) just go through the header, it will have all the function you need to manipulate your ADB.

It will have following set of functions,

To create and free the object

adb_myDemo_create
adb_myDemo_free


Getters and Setters to manipulate Data

adb_myDemo_get_demo1
adb_myDemo_set_demo1
adb_myDemo_get_demo2
adb_myDemo_set_demo2


Build and Parse XML

adb_myDemo_serialize
adb_myDemo_deserialize

First we will check how to build a simple XML using an ADB object.

    adb_myDemo_t *mydemo = adb_myDemo_create(env);
    adb_myDemo_set_demo1(mydemo, env, 3); /* some arbitrary value */
    adb_myDemo_set_demo2(mydemo, env, "some arbitrary string");
    axiom_t *xml = adb_myDemo_serialize(mydemo, env, NULL, NULL, AXIS2_TRUE, NULL, NULL);

So now we have the AXIOM representation of the XML which we just build using ADB.

<ns0:myDemo xmlns:ns0="http://dimuthu.org/adb/demo/2008/sept">
    <ns0:demo1>3</ns0:demo1>
    <ns0:demo2>some arbitrary string</ns0:demo2>
</ns0:myDemo>

Anyway ADB is easier when you want to navigate through an XML. (you can read data randomly as you preferred). Here we starting from the AXIOM representation of our XML.

      adb_myDemo_t *mydemo= adb_myDemo_create( env);
      adb_myDemo_deserialize(mydemo, env, &xml, NULL, AXIS2_FALSE))
      int demo1 = adb_myDemo_get_demo1(mydemo, env);
      printf("My Demo1 is: %d\\n", demo1);
      axis2_char_t *demo2 = adb_myDemo_get_demo2(mydemo, env);
      printf("My Demo2 is: %s\\n", demo2);

I have printed the Data contained in the XML with the help of ADB objects.

In ordre to download the Codegen tool with ADB you have to download the Axis2/Java package.

If you want to learn more about ADB, Just go through more Axis2/C Codegen / ADB resources which I have blogged few weeks ago.

In a WSDL, XML Schema is the section where it define the message format for each operations, which eventually become the real API that users are interested. And it is the most tricky part of the WSDL. Nowadays there are many tools that you can design and use WSDLs without any needs in knowing the meaning of a single line of the WSDL. But there are situations that you may find it is better you have some knowledge in XML Schema section and in WSDL overall.
For this post I m taking a simple example of use of nillable=”true” and minOccurs=”0″. Take the following example.

<xs:element name="myelements">
  <xs:complexType>
    <xs:sequence>
     <xs:element name="nonboth" type="xs:string"/>
      <xs:element minOccurs="0" name="minzero" type="xs:int"/>
      <xs:element name="nilint" nillable="true" type="xs:int"/>
      <xs:element name="nilstring" nillable="true" type="xs:string"/>
      <xs:element minOccurs="0" name="minzeronil" nillable="true" type="xs:string"/>
    </xs:sequence>
  </xs:complexType>
</xs:element>

Just ignore the meaning of what nillable and minOccurs attributes for now. You can safely say the following XML is valid for the above Schema.

<myelements>
  <nonboth>i can't be either nil nor skipped<nonboth>
  <minzero>3<minzero>
  <nilint><nilint>
  <nilstring>i can have null, but i cant skipeed</nilstring>
  <minzeronil>i can be skipped and have the nil value<minzeronil>
</myelements>

Take the first element ‘nonboth’ in the schema, It has not any minOccurs or nillable attribute. By default minOccurs equal to 1 and nillable equal to false. That mean it can’t have nil value nor it can not be removed from the xml.

Is that making an element nil and removing the element from the XML is same? No. Take the second element in the schema ‘minzerostring’. There you have minOccurs =”0″ but there are no nillable=”true”, mean it is non-nillable. The idea is whenever you don’t want that element in your xml, you can’t have the element keeping empty like

  <minzero xsi:nil="true"><minzero>

But you can remove the whole element from the XML (since it is minOccurs=0).

The opposite of the above scenario is nillable=”true” but minOccurrs != 0. Check the ‘nilint’ element in the schema. There you can’t skip the element ‘nilint’, you have to have the element <nilint/> but it can hold a nil value.

  <nilint xsi:nil="true"></nilint>

or simply

  <nilint xsi:nil="true"/>

Note that the correct way to declare the nil element is,

  <nilint xsi:nil="true" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"/>

You can understand why when we look at the third element ‘nilstring’. Say you set message the following element

  <nilstring></nilstring>

You can say that this is not nil, this is an empty string. In fact an empty string is nil in some other language, But if we take XML Schema as a language, then for someone to be nil, it have to have the xsi:nil attribute set to “true” or “1″.

So going back to the ‘minzero’ which is non-nillable, by theory you should be able to write the following xml,

  <minzero/>

Since you don’t have that xsi:nil=”1″ this is not a nil value, so the condition nillable=”false” condition is preserved. But unlike for string when you set an empty element for an integer, it doesn’t sound correct. So in practice whenever some schema says non-nillable you should set some valid value.

The last one is ‘minzeronil’ element which is both nillable=”true” and minOccurs=”0″. Whenever you don’t need to set a value for this element, you have the choice of either skipping the element or setting the value of the element to nil. It is obvious rather than setting a nil value it is better you just skip the element to make the XML shorter. This is really needed specially in web services where you need the payload to be minimum as much as possible.

Say you have to prepare the XML and you don’t have valid values for any of the element. So this can be the optimum XML you can create.

<myelements xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"/>
  <nonboth><nonboth>
  <nilint xsi:nil="1"/>
  <nilstring xsi:nil="1">
</myelements>

Read this nice article in developer works on nillable=”true” and minOccurs=”0″ for more.