webservices

Applications / PHP

SOAP Server and Client, now with WSDL part 2

Now here is the part where I give the example files. After we have planned the application functions, we need to figure out what we are going to return to the client. This is going to be a standard array with at least two levels: The Response array and the Data array. It will look similar to this:

Array
(
    [responseMsg] => Array
        (
            [status] => ok
            [message] => Service call was successful
        )
    [allColors] => Array
        (
            [0] => blue
            [1] => green
            [2] => black
            [3] => white
            [4] => yellow
            [5] => red
            [6] => beige
        )
)

Now that we have the basic idea, we need to create the WSDL file. Remember, it is very important to think of WSDL files as of reading from bottom to top. The final WSDl file is located here. Here is the basic idea of the WSDL file I created (going from the bottom to the top):

  1. Service: This houses the binding, the location, the port, and the name.
  2. Binding: This houses the functions that will be exposed, the operation and the input and output encoding. Most of the time these will be similar with only the names being different.
  3. Port Type: Here is where I define the operations and the input/output definitions
  4. Message: These are individual nodes for the Request and Response messages for all functions. These will usually have two message nodes per function, and they will define the structure for each action
  5. Types: This defines each structure that has been mentioned in the Message and any subsequent structures that have to be defined. This is usually the area where most struggles occur.
    • This structure will be encompassed by schema target namespace
    • Import the XML namespaces to help build the structures in the reasponse
    • For each complex type, it should either mention a specific data type (xsd:), or a new defined structure (tns:)
    • Each structure that is an array should be defined as a SOAP-ENC:Array with a wsdl:arrayType parameter

So that is the WSDL. The one I have created defines the 2 functions, the input, the output, and the structure of each. Now we can move on to the Server code.
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3 Comments
Wednesday, May 25, 2011
Applications

Testing the NuSOAP Webservice in C#

For the past few posts, the main focus has been a NuSOAP Webservice that does really basic things with very limited data. The different functions of the service have done a variety of things:

  • showNumbers – Returns an array of numbers in a non-assoc array key format
  • showMadLib – Returns a mad lib based on the data it is sent. Need 4 Adjectives, 2 Adverbs, 3 Nouns, 1 Verb, and 2 Verb: Past Tense. It replies with a string that contains the madlib.
  • showGroupItems – Simplistic service to return an array of items for a specific event, the ones available are: movie, picnic, drive, shopping
  • showTaxes – Shows the taxes based on state taxes. Currently, the only states available in this are: AZ,AL,AK, CA, OR, WA, UT, ID, WY, Defaults to CA if no state is provided. The input for this function is an array.
  • showPhrases – Shows a phrase from Shakespeare and replaces the name with the supplied name. ID is a number from 0 – 4

Although these are very basic and the real world applications are very limited, it can provide a spring board to building real world webservices that can be used for a variety of reasons. But, the power of webservices are that they can be code independent if written correctly. The server portion we have done is all in PHP. The client we have tested this on has been a PHP base. Based on the client functioning properly, we know that PHP based applications will be able to access the data. But the web is not 100% PHP based. Other code exists, which could be .NET flavors, Java, even ColdFusion. We need to ensure that the webservice built will be accepted by applications written in other languages.
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Sunday, August 15, 2010
Applications / PHP

Finishing up the NuSOAP server

In the last post, the NuSOAP server introduced a new level of complexity, and had a multidimensional array, along with creating a more robust status message for the client to help determine the success or failure of the request. This post will examine the remaining functions in the NuSOAP server, and making the rest of the functions work, and more complex types including third and fourth level complexities along with a non-named (integer) array for the result.

We will be building on the code we used last time, so as a refresher, the code from the last post can be located at:
http://www.hirdweb.com/webservice/20100710_server.txt
http://www.hirdweb.com/webservice/20100710.txt

First off, here are the remaining functions to be exposed in the service:

  • showGroupItems – Shows what is needed based on a set event, all items are made up of course
  • showMadLib – Returns a mad lib based on passing in a number of different items
  • showNumbers – Returns a non associative array of numbers, requires an ID, and returns the numbers associated with that ID

Each of these webservices will require a little different structure.
showGroupItems will have a third level of complexity
showMadLib will require a long list of strings as the input
showNumbers will return an array of string elements, integer value for the element, instead of a named element
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1 Comment
Tuesday, July 20, 2010
Applications

Building on the NuSOAP Server

The NuSOAP server consists of a function that will take an ID and a name/phrase and inserts that into the Shakespeare quote. The function returns a semi-complex type which consists of 2 array elements, a status message and the phrase. However, the webservice needs to expand, add a new function, and make error messages dynamic. So the first thing we will tackle is getting the status message into a more dynamic format.

First, plan it out, always plan it out. The status message will need to accept an “error code”, a string for the struct name, and a variable for a custom message if it does fit in within the specified error codes. Now, just as a disclaimer here, this is just an example of how it can be planned. Some services may not need this extent, some may need a lot more. Remember that it needs to be able to handle the requirements of your application.

With that planned out, here is a possible solution to the function. 

function error($err, $struct = 'phrase', $message = ''){
	$error['status']['status']='error';
	$error[$struct]= '';
	switch ($err) {
		case "empty":
			$error['status']['message']='There was nothing passed to the webservice, so nothing can be returned.';		
			break;
		case "partial":
			$error['status']['message']="Not all required parameters were passed, so the webservice can not return any information.";
			break;
		case "not_found":
			$error['status']['message']='The parameter you passed was not found, please try again.';
			break;
		case "bounds":
			$error['status']['message']='The ID that was passed is out of the allowable boundaires. Please try your request again.';
			break;
		case "less_than_zero":
			$error['status']['message']='The number recieved is less than zero, and will not work with this service. Please double check the number and try again.';
			break;
		case 'custom':
			$error['status']['message'] = $message;
			break;
		default:
			$error['status']['message'] = 'There was a problem with your request, please try again.';
			break;
	}
	return $error;	
}

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2 Comments
Saturday, July 10, 2010
Applications

Simple NuSOAP Server

In the previous post, we examined the client side of NuSOAP. In this post, we examine a very simplistic approach to building a server. In this example, it is going to use a very basic set up, and will return only a string. No complex data will be returned, and it will be a quick look at how to create a NuSOAP server. The more complex approaches will come later.

Using the previous information in the post, we have a client that we can text the service on. Before I complete the webservice server, I always do some quick testing of the functionality before sending it to the web service. In this example, we will use one of the services built previously:
showPhrases – Phrases from Shakespeare plays that replace the names in the phrase with the passed in name/string

This webservice requires 2 items to be passed:
id – A number from 0 to 4 (In this example I only used 5 phrases)
name – A name or variable that can be used to replace the names in the phrases

The first thing we should always do, is map out the plan for this function.
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5 Comments
Wednesday, July 07, 2010
Applications / PHP

Web Services with NuSOAP

Doing a lot with webservices lately. Which is really a great thing if there is a central repository of information that needs to be disseminated between different external systems. I am doing a lot with NuSOAP and php SOAP. But this tutorial is going to be about the NuSOAP libraries. You can get these libraries from:
http://sourceforge.net/projects/nusoap/

First thing to do is to download this, and install into a directory that you can access. For different security reasons, it may be needed to keep these libraries outside of the accessible web directories.

The next step is to determine what needs to be required to get the data. This may include authentication and credentials, id’s, phrases, or anything else. It could be possible to not have anything required and just return all records. And that is the next step: determine what to expose. What type of information would you want to send back to the world? Hopefully it is not sensitive data, and only the data that needs to be exposed.

Now with that in mind, we are ready to go. I have set up a webservice server that has five different functions:

showPhrases – Phrases from Shakespeare plays that replace the names in the phrase with the passed in name/string
showTaxes – Calculates the tax based on the passed in price and state
showGroupItems – Shows what is needed based on a set event, all items are made up of course
showMadLib – Returns a mad lib based on passing in a number of different items
showNumbers – Returns a non associative array of numbers, requires an ID, and returns the numbers associated with that ID

Each of these functions provides a little more to view based on the webservice. The first and fourth functions will return a string of data. The second function returns an array with different data types. The third returns a complex type of a multidimensional array. I did this because there are many different tutorials out there using NuSOAP, but only seem to return a basic type and has very little to help when setting up the WSDL when it needs to be more complex. The fifth function demonstrates how to return a non associative array with the webservice in a complex type.

I will break down each function per post. But now we need a way that we can test these functions when we get them going. So the first thing to do is create a NuSOAP client to grab the exposed data. For the client, we will use the showTaxes example that has been created.

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Friday, July 02, 2010