Network Deployment (Distributed operating systems), v8.0 > Set up intermediary services > Set up the proxy server


Create a custom filter and deploying it to a proxy server

We can create a custom filter for your proxy server if you need to have the proxy server perform a function, such as customized logging, that is not provided through normal product settings.

A filter provides an optional, secondary control over a function, that is beyond the control that is normally provided through typical product settings. For example, an applications might use a logging filter mechanism to suppress all of the events that have a particular message key.


Procedure

  1. Create a custom filter.

    1. Create a class that extends com.ibm.wsspi.HttpDefaultFilter.
    2. Override the abstract doFilter method, and, optionally, the init and destroy methods. If you override the init and destroy methods, call the super versions of these methods to preserve filter lifecycle functionality.
    3. Write a new doFilter method, that uses the HttpProxyServiceContext interface.

      This new doFilter method can be written such that it:

      • Changes any artifacts that are associated with the request or the response, such as the response itself, the response code, or the headers.
      • Changes any artifacts that are associated with both the request and the response.
      • Obtains information about either the request or the response.
      • Obtains information about both the request and the response.

    4. Use the proxy server filter managed bean (MBean), proxyFilterMbean, to determine the correct ordinal for the filter. 
      proxyFilterMbean = AdminControl.queryNames('type=ProxyServerFilterBean,*')
AdminControl.invoke(proxyFilterMbean, 'viewAllFilters')
      The order, in which all of the filters on the proxy server are processed, displays.

    5. Create the filter descriptor file, filter-context.xml

      This file is used to define all of the filters that have this descriptor. The following example illustrates a basic version of a filter-context.xml file.

      In this example. the descriptor determines where and when the given filter is executed on both the request and the response. The filter point determines where the filter is executed. In this example, the filter executes after the request is received. The ordinal determines when the filter gets processed relative to other filters at the same filter point. The higher the ordinal, the higher the filter is in the processing queue. 

      <?xml version="1.0" encoding="UTF-8>
<filter-context xmlns="http://www.ibm.com/2003/FilterContextSchema">
<description>Proxy Filter Sample descriptor
</description>
<display-name>Proxy Sample Filter
</display-name>

<filter>    
<filter-name>HttpRequestFilter
</filter-name
   
<filter-class>com.ibm.ws.proxy.sample.HttpRequestFilter
</filter-class>    
<description>HTTP sample filter to execute at REQUEST filter point
</description>    
<display-name>HTTP Request Sample
</display-name>    
<protocol-name>HTTP
</protocol-name>          
<filter-point>RequestReceived
</filter-point>    
<ordinal>1000
</ordinal>
</filter>
</filter-context>
    6. Bundle the compiled .class files for the filter, and the filter descriptor into a JAR file.

  2. Import the artifact (JAR file) that contains the custom filter.

    1. In the administrative console, click Applications > Application Types > Assets > Import.

    2. Select either Local file system or Remote file system to indicate where the JAR file is located.

    3. Specify the fully qualified name of the JAR file.

      The fully qualified name of the JAR file includes the directory path to where the file is located, and the file name. If you do not know the fully qualified name of the JAR file, you can use the browse function to locate the file.

  3. Create a business level application (BLA) that includes this artifact.

    1. In the administrative console, click Applications > New Application > New Business-level application.

    2. In the Name field, specify a name for the new application that you are creating.

      You can also specify a description of the application in the Description field.

    3. Click Apply.

  4. Create a BLA composition unit (CU) from the artifact.

    1. In the Deployed assets table, click Add > Add asset.

    2. Select the name of the artifact that you imported in the first step, and then click Continue.
    3. Change the composition unit settings as needed, and then click Modify target.

    4. Select the proxy server on which to deploy this CU from the list of available deployment targets, and then click OK.

      When you click OK the product maps the composition unit to the selected proxy server.

    5. Specify the relationship options for this composition unit.

    6. Click Finish.

    To verify that the product successfully added the created this CU, click Applications > Business-level applications > application_name. If the product successfully adds the CU, the name of the CU is shown in the list of deployed assets for this BLA.

  5. Start the proxy server.

  6. Start the BLA that contains the filter.


Results

The filter is running on the proxy server.


What to do next

Use the proxy server filter MBean, proxyFilterMbean, to verify that the filter is installed on the proxy server and that is is being processed in the correct order relative to the other filters that are deployed on the proxy server. If change the order in which this filter is processed, run the modifyOrdinal command against the proxyFilterMbean MBean.
Create business-level applications with the console
Set up the proxy server

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