Web Services Proxy

W

What is a proxy web service? - Stack Overflow

What is a proxy web service? – Stack Overflow

What is a proxy web service??
asked May 12 ’10 at 11:18
AzharAzhar19. 5k38 gold badges134 silver badges204 bronze badges
A client and a Web service can communicate using SOAP messages, which encapsulate the input and output parameters as XML. A proxy class maps parameters to XML elements and then sends the SOAP messages over a network. In this way, the proxy class frees you from having to communicate with the Web service at the SOAP level and allows you to invoke Web service methods in any development environment that supports SOAP and Web service proxies.
Example:
Client calls the proxy’s method, Login(username, password).
The proxy serializes these parameters into a SOAP message, and sends it over HTTP to the Web service.
The Web service returns the result (true or false in this case) of Login() method call serialized in a SOAP message.
The proxy class deserializes the response, and returns the boolean value true to the client application.
approxiblue6, 69416 gold badges48 silver badges56 bronze badges
answered Dec 18 ’15 at 5:26
By default, the proxy class uses SOAP over HTTP to communicate with the XML Web service. However, can generate proxy classes to communicate with an XML Web service, using either the HTTP-GET protocol or HTTP-POST protocol.
More about how to use web service proxy:
John Saunders158k24 gold badges231 silver badges390 bronze badges
answered May 12 ’10 at 11:22
Pranay RanaPranay Rana166k34 gold badges230 silver badges257 bronze badges
Not the answer you’re looking for? Browse other questions tagged web-services or ask your own question.
What is a proxy web service? - Stack Overflow

What is a proxy web service? – Stack Overflow

What is a proxy web service??
asked May 12 ’10 at 11:18
AzharAzhar19. 5k38 gold badges134 silver badges204 bronze badges
A client and a Web service can communicate using SOAP messages, which encapsulate the input and output parameters as XML. A proxy class maps parameters to XML elements and then sends the SOAP messages over a network. In this way, the proxy class frees you from having to communicate with the Web service at the SOAP level and allows you to invoke Web service methods in any development environment that supports SOAP and Web service proxies.
Example:
Client calls the proxy’s method, Login(username, password).
The proxy serializes these parameters into a SOAP message, and sends it over HTTP to the Web service.
The Web service returns the result (true or false in this case) of Login() method call serialized in a SOAP message.
The proxy class deserializes the response, and returns the boolean value true to the client application.
approxiblue6, 69416 gold badges48 silver badges56 bronze badges
answered Dec 18 ’15 at 5:26
By default, the proxy class uses SOAP over HTTP to communicate with the XML Web service. However, can generate proxy classes to communicate with an XML Web service, using either the HTTP-GET protocol or HTTP-POST protocol.
More about how to use web service proxy:
John Saunders158k24 gold badges231 silver badges390 bronze badges
answered May 12 ’10 at 11:22
Pranay RanaPranay Rana166k34 gold badges230 silver badges257 bronze badges
Not the answer you’re looking for? Browse other questions tagged web-services or ask your own question.
Web Service Proxy Service - IBM DataPower for Beginners and ...

Web Service Proxy Service – IBM DataPower for Beginners and …

———————————————————————————————————–
Introduction
A key aim of SOA is to loosely couple service requestors and service providers. Decoupling the service implementation from the service interface is one step, so that changing the provider’s service implementation does not require any changes to the service requestor. But what about the service endpoint — using a static endpoint provided by the service description (WSDL) means coupling the requestor and provider at the transport level:
Figure 1. Transport level coupling
Every time the physical endpoint of the service provider changes, every service consumer must reflect the changes in its application logic. A better solution is to use an intermediary that intercepts a service call and routes it to the appropriate endpoint. Abstracting from transport-specific information to have a transparent intermediary layer between service consumers and providers is one aspect of the Enterprise Service Bus (ESB) pattern. The WebSphere DataPower SOA Appliance and its Web Service Proxy component can be part of an ESB implementation by acting as such an intermediary layer. Implementing this part of an ESB layer in a static way by referencing WSDL files in the WS-Proxy component and providing a static service endpoint to the consumer provides a single point of control when changes are made to the real service endpoint, thus simplifying management of the service endpoint. With this approach, the service consumer is decoupled from the provider at the transport level, but changes on the proxy side are still necessary when changes are made on the providers endpoint.
Figure 2. Decoupling with WS-Proxy
Using DataPower’s WebSphere Service Registry and Repository subscription feature inside the service proxy instead of statically referencing the WSDL file is the way to get a more dynamic service intermediary. DataPower can subscribe to WSDL files or to other artifacts stored in WebSphere Service Registry and Repository, and synchronize with changes either automatically by polling or manually driven from outside. Form a service endpoint management point of view, this approach provides a flexible and dynamic ESB layer functionality that reflects changes to the endpoints automatically without having to make changes on the service consumer nor on the ESB side:
Figure 3. Dynamic decoupling with WS-Proxy
This article describes how to set up such an dynamic Web service proxy with WebSphere Service Registry and Repository and DataPower. The article first describes the basic configuration — how to set up the WS-Proxy and connect it to WebSphere Service Registry and Repository to subscribe to service definitions. The article then describes fault handling, schema validation, and how they can be realized in the WS-Proxy component of DataPower.
Prerequisites
The following prerequisites are required to set up the described scenario:
WebSphere DataPower SOA appliance with firmware V3. 6. 0. 8 or later
This article uses a DataPower XI50 Appliance with firmware V3. 14. The WSRR subscription feature was introduced in V3. 8.
WebSphere Service Registry and Repository V6. 0 or later
The article uses WebSphere Service Registry and Repository V6. 2, but the DataPower subscription works for earlier and later versions as well. WebSphere Service Registry and Repository V6. 1 will available in 1Q 2008.
Web service requestor application
Either you have a Web service requestor application or you can use the Web service explorer feature of WebSphere Integration Developer V6 or Rational Application Developer V6 or V7.
Web service provider application
You can use any Web service as long you have the corresponding WSDL file. You can download a sample Web service application below and deploy it on WebSphere Application Server V6. 0 or later. WebSphere Service Registry and Repository is running on top of a WebSphere Application Server V6. 2. 17, so if you have free access to this WebSphere Service Registry and Repository installation, you can use it to host the Web service application. The sample application contains a simple Web service called Order Service. The request data type is a order object, which consists of a customer object and 1:n item objects. When no error occurs, the Order Service responds with a order confirmation containing an order id. This order id is hard-coded in the service implementation so the value is always the same.
WebSphere Service Registry and Repository configuration
Before you can start to configure the WS-Proxy in DataPower, you must register the Web service you want to subscribe to in WebSphere Service Registry and Repository, as described below.
Upload files
To register the Web service in WSSR, upload the WSDL and all of its dependent XSDs via the administrative console, as shown below. The administrative console is provided via a Web interface — to access it, use a browser and enter the URL of your WebSphere Service Registry and Repository installation. The URL of the administrative console has the following structure: :/ServiceRegistry. For example: localhost:9080/ServiceRegistry.
Figure 4. XSD dependencies
The minOccurs attribute of the customer and the order element is set to 1, meaning that these objects are required in every order request. Later you will use that fact to cause a validation error in the Web service proxy.
Log in to the administrative console
Enter the URL of your WebSphere Service Registry and Repository installation. When the login screen opens, log in with your credentials. If you don’t have configured security, you will be forwarded to the administrative console:
Figure 4a. WSRR administrative console
Upload the XSD files.
Under Service Documents go to XSD Documents and upload,, and by clicking Load Documentand following the instructions. Beside giving a description of the datatype you are uploading, you can provide a version number such as 1. 0 (or you can leave it blank). The XSD Documents page should look like this:
Figure 5. XSD import
Upload the WSDL file.
After you have successfully uploaded the XSD documents, you can upload the WSDL file. Under Service Documents go to WSDL Documents and upload the WSDL in the same manner as you did with the XSD documents. Your WSDL Document page should show the WSDL file:
Figure 6. WSDL import
You have now registered the Order Service in WSRR, so you can now query this service definition using DataPower.
WS-Proxy configuration
In this step, you configure the DataPower device. First, log in to the device and your domain (Figure 6a). Before creating the Web service proxy, you must define a Http Front Side Handler object and a WSRR Server object, which will both be used by the Web service proxy. The Http Front Side Handler object will listen on a specific URL and will route the HTTP requests sent to this URL to the Web Service Proxy service. The WSRR server object is the definition of the WSRR you want to use for the subscription of service definitions.
Figure 6a. DataPower login
Preparing configuration objects
The following section shows you how to create and configure the objects used by a Web Service Proxy service:
WSRR Server Object
Under the left navigation pane on the DataPower Web GUI, navigate to the Objects section and click WSRR Server in the Configurationsection. A list of all WSRR server definitions opens. Click Add to define a new WSRR Server:
Figure 7. WSRR server configuration
Assign a name such as MyWSRRServer to your WSRR server. In the SOAP URL field, replace hostname and port number with the values of your WSRR installation. When your are running WSRR without security, your protocol will be HTTP. When your are running WSRR with security enabled, provide an SSL proxy profile, username, and password. For information on how to configure an SSL proxy profile, see the DataPower documentation. Click Apply. The Web GUI switches back to the WSRR server list, where your WSRR server definition should appear.
HTTP Front Side Handler
It is not mandatory to define the HTTP Front Side Handler in the following way. During the creation of the Web service proxy, you will be able to choose a default HTTP Front Side Handler. You would have to change this default HTTP Frontside Handler to your requirements anyway. Under the left navigation pane on the DataPower Web GUI navigate to the Objects section and locate the HTTP Front Side Handler link in theProtocol Handlers subsection. After clicking this link a list with all HTTP Front Side Handler definitions will appear. Click add to define a new HTTP Front Side Handler. You can keep all defaults.
In the name field choose for example MyHTTPFrontsideHandler as name of the new handler. As Local IP Address choose the IP address of one of the ethernet interfaces. You can figure out this IP address at the right navigation pane under Status, IP Network, Ethernet Interfaces. If you leave the default 0. 0, you will reach the HTTP Frontside Handler on all configured ethernet interfaces. Under Port Number fill in a port which isn’t already used by the DataPower device, for example 9080. If you want to be able to retrieve the new WSDL of the Order Service (generated by the WS-Proxy) with? wsdl in your browser you have to enable the HTTP GET method, too. Here are the settings:
Figure 7a. HTTP frontside handler configuration
Save your configuration on the upper right of the Web GUI: Click Save config.
Figure 7b
Setting up WS-Proxy Service
In order to create a new Web Service Proxy click on the Web Service Proxy Icon on the Control Panel:
Figure 8. DataPower control panel
Specify the name for the Web Service Proxy Object and choose the way you want to add the WSDL files. In order to be able to subscribe to service definitions stored in WSRR choose Add WSRR Subscription:
Figure 9. WS-Proxy configuration
Add a HTTP Front Side Handler and WSRR Server object to your Web Service Proxy service. Choose the previously created WSRR Server and HTTP Front Side Handler. Also the settings in Table 1 have to be applied to the configuration page.
AttributeValue
WSRR Subscription NameMyServiceSubscrition
WSRR ServerMyWSSRServer
Subscription ObjectWSDL Document
NamespaceObject
Local Endpoint HandlerMyHTTPFrontsideHandler
Local URI/services/OrderService
Your configuration now should look like this:
Figure 10. WS-Proxy subscription
After verifying your settings, save your configuration on the upper right of the Web GUI by clicking Save config.
Verifying subscription status
First examine the status of the WSRR subscription. Under Status in the left navigation pane you can find WSRR Subscription Status and WSRR Subscription Service Status under the Web Service subsection. Click on both and examine the status and the retrieved information. When all worked fine the two status tables should look like Figure 10a and 10b:
Figure 10a. WS-Proxy subscription service status
Figure 10b. WS-Proxy subscription service status
Verifying the endpoint information
Now examine if DataPower has retrieved the right endpoint information from WSRR. Return to the Status section and under the Web Servicesubsection click on Web Service Operations. There will be a table with all currently registered Web Service operations. The very last column on the right shows the back end address which is the service endpoint DataPower has retrieved from the service definition in WSRR. Figure 10c shows the last two columns of this table.
Figure 10c. Web service operation
Testing the WS-Proxy
The Web service proxy now is ready for a first test. The new external endpoint of the Web service is the Local IP Address and the Port Numberof the HTTP Frontside Handler followed by the Local URI of the WSRR subscription (:9080/services/OrderService). You can use any Web service client to send a valid SOAP request to the Web service proxy’s endpoint. In order to get a better understanding of what happens you can use a TCP/IP monitor to examine the SOAP request and the SOAP response. For sending SOAP requests and examine the SOAP response you can also use the build in Web Service Explorer of the WebSphere Integration Developer or the Rational Application Developer. You can send any order information as long you have at least one required order object and one required customer object in your order.
Listing 1. Sample of a valid SOAP request






Peter
Jones
2838382128


837228304 3

8272666333 4




Listing 2. Response to a valid SOAP request














After you have created the XSLT File either via a text editor or a development tool you have to upload the file to the device. Go to the Web GUI again and select File Management under the Administration section of the left navigation pane or on the Control Panel. Under the of the local storage click on Upload Files:
Figure 19. Upload files
Rule configuration
Now the request rule and a new error rule has to be configured for having a kind of try and catch error handling.
Go to the default request rule (Figure 18) and drag the Advanced icon behind (form left to right) the Match action. Double click on the new yellow squared Advanced icon:
Figure 20. Advanced action
Activate the on-error radio button and click Next. Now the configuration wizard of the on-error action will appear. On this configuration page it has to be specified which data are used for input of the on-error rule and which data is used as output. In DataPower this data containers are called context. Since we want to build a new SOAP Fault message we can use any input but must use the OUTPUT context for output, because the result of the on-error action processing is written to this OUTPUT context. So specify (auto) as input of the on-error action and OUTPUTas output. Error Mode will be abort because we don’t want to correct the error and continue but discard the request and send back an error to the client. Click Done:
Figure 21. On-error action configuration
After that a processing rule has to be defined. This rule determines the actions which has to be taken when the on-error rule is triggered. So click on the + sign to create a new processing rule. Name the new processing rule MyErrorRule and choose error-rule as Rule Direction. Now add a action to this rule which executes the previously created XSL stylesheet. Click the + sign on the lower right and name the actionMyErrorAction. Choose xform as Action Type and use your recently uploaded stylesheet in the Transform field. Input will be INPUT andOutput will be OUTPUT. You can now save all opened windows by pushing either Apply or Done. Here are the settings:
Figure 22. Transform error action
Don’t forget to apply the changes also to the policy on the left top of the policy configuration page, which should now look like this:
Figure 23. Rule with error handling
Now you should save your configuration and test your changes by sending the invalid SOAP request. The SOAP Fault message should not be the “Internal Server Error” anymore but detailed information about the validation error.
Conclusion
After doing the configuration work described above, you have now a dynamic Web Service Proxy, which is able to subscribe to service descriptions stored in WebSphere Service Registry and Repository. Beyond the more flexible decoupling of service consumer and provider, the WS-Proxy component in DataPower supports many additional service intermediaries. For more information, see Resources below. For example, WS-Proxy can act as an XML firewall, service-level monitor, and security policy enforcement point:

Frequently Asked Questions about web services proxy

What is a web service proxy?

A Web Service Proxy can handle traffic for all endpoints that are described in multiple WSDL files. For example, a Web Service Proxy might include the following WSDL files. A WSDL file for service endpoints that query accounts. A WSDL file for service endpoints that modify accounts.

What is SOAP proxy?

A client and a Web service can communicate using SOAP messages, which encapsulate the input and output parameters as XML. … Client calls the proxy’s method, Login(username,password). The proxy serializes these parameters into a SOAP message, and sends it over HTTP to the Web service.May 12, 2010

What is web service proxy in DataPower?

Web Service Proxy is a powerful service in DataPower which provides abstraction and security to the backend web services.It provide access to variety of web services. WSP has many important characteristics like. URI abstraction. Schema Validation. Building operation level rules.Apr 28, 2016

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