Skip to main content

Building the Foundation of the PO System: Web Service , SOAP , WSDL and UDDI


  1. Web Service and Communication:

    • A web service is like a reusable function available on a server.
    • Think of it this way: when you order something online, you're sending a request to the server, and the response you receive is like the confirmation of your order.
    • The difference from regular web browsing (HTTP) is that web services are like specific functions that you request to use. It's like the difference between viewing a webpage (HTTP) and actually making something happen on that webpage (web service).
    • For example, consider a weather forecasting web service. If you want to know the weather for a certain location, you send a request, and the service responds with weather data.

    • Example of Web Service Communication:
    • Imagine you have a web service that translates English to French.

    • You send a request like this:

      <translateRequest> <sourceLanguage>English</sourceLanguage> <targetLanguage>French</targetLanguage> <text>Hello, how are you?</text> </translateRequest>
    • The service processes this and responds with an XML like:

      <translateResponse> <translatedText>Bonjour, comment ça va ?</translatedText> </translateResponse>
    • Advantages of Web Services:

      • Reusability: Functions can be used across different applications.
      • Interoperability: Web services can work regardless of the programming languages or platforms used.
      • Scalability: Multiple clients can simultaneously access a single web service.
  2. Web Service Components:

    • XML (eXtensible Markup Language): Contains data and defines which service to call.
    • SOAP (Simple Object Access Protocol): A communication protocol that goes beyond regular HTTP. It wraps XML messages for sending and receiving between the client and server. SOAP ensures messages are understood by both sides.
    • WSDL (Web Services Description Language): Describes what's inside a web service, its operations, input, output, etc.
    • UDDI (Universal Description, Discovery, and Integration): A sort of dictionary that keeps track of all available web services. It helps clients find and understand services.

  3. SOAP Message Format and Example:

    • A SOAP message is like a letter with specific parts: the envelope and the content.
    • The envelope contains information like the sender, receiver, and the action needed.
    • The content holds the actual data being sent.

    Example of SOAP Message:

    • Consider a simple calculator service.
    • The request envelope might look like this:

      <soap:Envelope xmlns:soap=""> <soap:Body> <AddNumbersRequest> <Number1>5</Number1> <Number2>10</Number2> </AddNumbersRequest> </soap:Body> </soap:Envelope>
    • The response envelope:

      <soap:Envelope xmlns:soap=""> <soap:Body> <AddNumbersResponse> <Result>15</Result> </AddNumbersResponse> </soap:Body> </soap:Envelope>

    Example of WSDL:

    • Imagine you have a currency converter service.
    • The WSDL might define operations like ConvertCurrency with inputs and outputs.
  4. Here's a simple example of a WSDL definition for a web service that converts currency from Indian Rupees (INR) to US Dollars (USD):

    <?xml version="1.0" encoding="UTF-8"?> <wsdl:definitions xmlns:wsdl="" xmlns:soap="" xmlns:tns="" targetNamespace=""> <wsdl:message name="ConvertCurrencyRequest"> <wsdl:part name="amount" type="xs:double"/> </wsdl:message> <wsdl:message name="ConvertCurrencyResponse"> <wsdl:part name="convertedAmount" type="xs:double"/> </wsdl:message> <wsdl:portType name="CurrencyConverterPortType"> <wsdl:operation name="ConvertCurrency"> <wsdl:input message="tns:ConvertCurrencyRequest"/> <wsdl:output message="tns:ConvertCurrencyResponse"/> </wsdl:operation> </wsdl:portType> <wsdl:binding name="CurrencyConverterBinding" type="tns:CurrencyConverterPortType"> <soap:binding style="document" transport=""/> <wsdl:operation name="ConvertCurrency"> <soap:operation soapAction=""/> <wsdl:input> <soap:body use="literal"/> </wsdl:input> <wsdl:output> <soap:body use="literal"/> </wsdl:output> </wsdl:operation> </wsdl:binding> <wsdl:service name="CurrencyConverterService"> <wsdl:port name="CurrencyConverterPort" binding="tns:CurrencyConverterBinding"> <soap:address location=""/> </wsdl:port> </wsdl:service> </wsdl:definitions>


    • This WSDL defines a currency converter web service.
    • It has a single operation, ConvertCurrency, which takes an amount of type xs:double (numeric value) as input.
    • The output of the operation is the convertedAmount of type xs:double.
    • The binding specifies the use of SOAP for communication over HTTP.
    • The soap:address element within the wsdl:service defines the location of the service.
  5. WSDL - Web Services Description Language:

    WSDL is like a detailed instruction manual for web services. It describes how you connect to a specific method or function that needs to be called on a remote server. It specifies important information like the data types, data elements, and the operations that can be performed using the service. WSDL also provides the necessary information about the URL where the service can be accessed.

    • Type: Defines the data types used in messages. For example, xs:double represents a numeric value.
    • Message: Describes the structure of input and output messages for operations.
    • Port Type: Defines a set of operations that can be performed. It's like a contract listing what's available.
    • Binding: Describes the communication protocol and message format. It tells you how to communicate with the service. It's like deciding whether to use phone calls or emails to talk.
    • Service: The actual implementation of the service, with a specific address (URL).

    SOAP vs. WSDL:

    • SOAP (Simple Object Access Protocol): It's like the language that messages are written in. It wraps around your data and ensures that it's understood by both the sender and receiver. It's the way information is packaged for delivery.
    • WSDL (Web Services Description Language): It's like the blueprint of the service. It tells you what methods are available, what data types they accept, and how to communicate with them.

    UDDI - Universal Description, Discovery, and Integration:

    Imagine you're in a big city, looking for a specific shop. UDDI is like a directory for services. It's a repository or dictionary where all the services are listed. It's a way to discover what services are available and how you can interact with them.

    • Service Requestor: This is you, the client, who wants to use a service.
    • Service Provider: This is the entity that hosts the service and provides the functionality.
    • Service Broker (UDDI): UDDI is the middleman. It's like the Yellow Pages for services. It helps you find the right service provider.

    Example Flow with Client, Server, and UDDI:

    1. You (Service Requestor) want to use a currency conversion service.
    2. You don't know where to find it, so you turn to UDDI (Service Broker).
    3. UDDI provides you with a list of available currency conversion services and their WSDLs.
    4. Armed with the WSDL, you now know how to communicate with the chosen service provider.
    5. You send a SOAP request (using the structure from the WSDL) to the service provider (Server).
    6. The service provider processes your request and sends back a SOAP response.

    This whole process is like finding a specific shop in a city using a directory, then understanding the shop's offerings through a detailed manual, and finally interacting with the shopkeeper using a specific language.

    Remember, UDDI helps you find the service, WSDL tells you how to talk to it, and SOAP ensures the communication is clear and understood. It's like discovering, understanding, and conversing in the world of web services.

Assuming you have a Calculator service with the following WSDL:


<wsdl:definitions xmlns:wsdl="" xmlns:tns="" targetNamespace=""> <!-- Define Types and Messages --> <wsdl:portType name="CalculatorPortType"> <wsdl:operation name="add"> <wsdl:input message="tns:AddRequest"/> <wsdl:output message="tns:AddResponse"/> </wsdl:operation> </wsdl:portType> <wsdl:binding name="CalculatorBinding" type="tns:CalculatorPortType"> <soap:binding style="document" transport=""/> <wsdl:operation name="add"> <soap:operation soapAction=""/> <wsdl:input> <soap:body use="literal"/> </wsdl:input> <wsdl:output> <soap:body use="literal"/> </wsdl:output> </wsdl:operation> </wsdl:binding> <wsdl:service name="CalculatorService"> <wsdl:port name="CalculatorPort" binding="tns:CalculatorBinding"> <soap:address location=""/> </wsdl:port> </wsdl:service> </wsdl:definitions>

Now, let's say you want to use the "add" feature of the Calculator service. Here's how you might do it using SOAP:

SOAP Request:

<soap:Envelope xmlns:soap="" xmlns:tns=""> <soap:Body> <tns:add> <tns:num1>5</tns:num1> <tns:num2>10</tns:num2> </tns:add> </soap:Body> </soap:Envelope>

In this example:

  • The WSDL (CalculatorService.wsdl) provides the structure of the service and its operations.
  • You access the "add" operation through the "CalculatorPort" defined in the WSDL.
  • The SOAP request is created with the necessary data (num1 and num2 representing the numbers you want to add).

When you send this SOAP request to the URL where the Calculator service is hosted (, the service will process the request and send back a response.

Remember, the WSDL guides you on how to structure your request, and SOAP ensures that your request and the service's response are properly wrapped for communication.


  1. Great I particularly appreciate the way you've broken down complex concepts into simple, easy-to-understand terms. software development in chennai


Post a Comment

You might find these interesting

How to properly Start/Stop SAP system through command line ?

Starting/stopping an SAP system is not a critical task, but the method that most of us follow to achieve this is sometimes wrong. A common mistake that most of the SAP admins do is, making use of the 'startsap' and 'stopsap' commands for starting/stopping the system.  These commands got deprecated in 2015 because the scripts were not being maintained anymore and SAP recommends not to use them as many people have faced errors while executing those scripts. For more info and the bugs in scripts, you can check the sap note 809477.  These scripts are not available in kernel version 7.73 and later. So if these are not the correct commands, then how to start/stop the sap system?  In this post, we will see how to do it in the correct way. SAP SYSTEM VS INSTANCE In SAP, an instance is a group of resources such as memory, work processes and so on, usually in support of a single application server or database server with

sapstartsrv is not started or sapcontrol is not working

 What is sapstartsrv ? The SAP start service runs on every computer where an instance of an SAP system is started. It is implemented as a service on Windows, and as a daemon on UNIX. The process is called  sapstartsrv.exe   on Windows, and   sapstartsrv   on UNIX platforms. The SAP start service provides the following functions for monitoring SAP systems, instances, and processes. Starting and stopping Monitoring the runtime state Reading logs, traces, and configuration files Technical information, such as network ports, active sessions, thread lists, etc. These services are provided on SAPControl SOAP Web Service, and used by SAP monitoring tools (SAP Management Console,  SAP NetWeaver  Administrator, etc.). For more understanding use this link : How to check if it is working or not ? In case of linux , you can simply ps -ef | grep sapstartsrv In case of windows, you need

HANA System Replication - Prerequisites & Setup

Hey Folks! Welcome back to Hana high availability blog series. In our last blog we checked out operation & replication modes in hana system replication. If you haven't gone though that blog, you can checkout  this link In this blog we will be talking about the prerequisites of hana replication and it's setup. So let's get started. When we plan to setup hana system replication, we need to make sure that all prerequisite steps have been followed. Let's have a look at these prerequisites. HANA System Replication Prerequisites: Primary & secondary systems should be up & running HDB version of secondary should be greater than or equal to Primary database sever But, for Active/Active(read enabled config), HDB version should be same on both sites. System configuration/ini files should be identical on both sides Replication happe

ST03N : The chapter for all BASIS Admins

This blog is targeted to BASIS ADMINS Transaction for workload analysis statistical data changed over time are monitored using transaction code ST03 , now ST03N (from SAP R/3 4.6C) . With SAP Web AS 6.4 the transaction ST03 is available again. From time to time ST03 and ST03N has seen many changes but later in SAP NW7.0 ST03N has reworked in detail specially processing time is now shown in separate column. Main Use of ST03N  is to get detailed information on performance of any ABAP based SAP system. Workload monitor analyzes the statistical data originally collected by kernel. You can compare or analyze the performance of a single application server or multiple application server. Using this you start checking from the entire system and finding your way to that one application server and narrowing down to exact issue. By Default :- You see data of current day as default view , you can change the default view. Source of the image : Let's discuss the WORKLOAD MONITOR By D

How to resolve Common Error : Standard Template "sap_sm.xls" missing

Hey everyone, putting forward a common error we usually face when we have “ Excel inplace” functionality enabled in our SAP system. This error occurs when validity of the signature of SAP standard templates expired or were incorrectly delivered via support packages. We can reproduce the error by doing as below.. Click on “spreadsheet” icon after any SAP ALV grid view of data is on screen to make this data to export into excel directly from SAP.

HANA hdbuserstore

The hdbuserstore (hana secure user store) is a tool which comes as an executable with the SAP Hana Client package. This secure user store allows you to store SAP HANA connection information, including user passwords, securely on clients. With the help of secure store, the client applications can connect to SAP HANA without the user having to enter host name or logon credentials. You can also use the secure store to configure failover support for application servers in a 3-tier scenario (for example, SAP Business Warehouse) by storing a list of all the hosts that the application server can connect to. To access the system using secure store, there are two connect options: (1)key and (2)virtualHostName. key is the hdbuserstore key that you use to connect to SAP HANA, while virtualHostName specifies the virtual host name. This option allows you to change where the hdbuserstore searches for the data and key files. Note

Work Process and Memory Management in SAP

Let’s talk about the entire concepts that are related to memory when we talk about SAP Application. Starting with few basic terminologies, Local Memory :  Local process memory, the operating system keeps the two allocation steps transparent. The operating system does the other tasks, such as reserving physical memory, loading and unloading virtual memory into and out of the main memory. Shared Memory :  If several processes are to access the same memory area, the two allocation steps are not transparent. One object is created that represents the physical memory and can be used by various processes. The processes can map the object fully or partially into the address space. The way this is done varies from platform to platform. Memory mapped files, unnamed mapped files, and shared memory are used.  Extended Memory : SAP extended memory is the core of the SAP memory management system. Each SAP work process has a part reserved in its virtual address space for extended memory. You can set

ABAP Dumps Analysis

Ever now and then have you heard about ABAP Dumps, We also have a joke everything in temporary in life except ABAP dumps for SAP Consultants. Lets try to understand ABAP dumps from perspective of a SAP BASIS Consultant. Dumps happen when an ABAP program runs and something goes wrong that cannot be handled by the program We have two broad categories of Dumps , In custom program Dumps and SAP provided program Dumps. Dumps that happen in the customer namespace ranges (i.e. own-developed code) or known as Custom Program , can usually be fixed by the ABAP programmer of your team. Dumps that happen in SAP standard code probably need a fix from SAP. You do not have to be an "ABAPer" in order to resolve ABAP dump issues. The common way to deal with them is to look up in ST22 How to correct the error ? Hints are given for the keywords that may be used to search on the note system. Gather Information about the issue  Go to System > Status and Check the Basis SP level as well as info

Complete Guide : XPI Inspector Tool

Content of this blog :           What is an XPI Inspector Tool ? Why XPI Tool is used ? XPI standard URL How to check XPI Tool version ? How to Install/Update XPI version using TELNET How to Use XPI Tool ? References – SAP Notes What is XPI Inspector tool ?          -    XPI Inspector is a diagnostics web application developed by SAP that collects logs and debug traces from various PI components in a very simple way and is useful for SAP PI consultants, developers, and administrators to get more insights on an issue. Why XPI is used  – 1.  Used to collect traces and logs from Messaging system or XI module. 2. Used to collect the related information to solving the issues or improving the PI or PO systems’ performance. 3. Using XPI Inspector application you will be able to collect a lot of information about your system that will help you to learn about problems in the past, to analyze new and detect such at an early stage. 4. Performs certain number of configuration checks, such as SSL c

SAP HANA System Replication - Operation Mode & Replication Mode

Hey Folks! Welcome back to Hana high availability blog series. In our last blog we checked out what is hana system replication and how it basically works. If you haven't gone through that blog, you can checkout link In this blog we will be talking about the replication modes and operation modes in hana system replication. So let's get started. When we setup the replication and register the secondary site, we need to decide the operation mode & replication mode we want to choose for replication. For now we won't focus on setting up replication as we'll cover it in our next blogs.  Operation Modes in Hana System Replication: There are three operation modes available in system replication: delta_datashipping, logreplay and logreplay_readaccess. Default operation mode is logreplay. 1. Delta_datashipping: In this operation mode initially one full data shipping is done as part of replication setup and then a delta data shipping takes place occasionally in addition to cont