Jython 2.7.4 · org.python.util.PyFilter · APIdia, the JavaDoc alternative

Enables you to write Jython modules that inherit from javax.servlet.Filter, and to insert them in your servlet container's filter chain, like any Java Filter.

Example:

/WEB-INF/filters/HeaderFilter.py:

from javax.servlet import Filter

# Module must contain a class with the same name as the module
# which in turn must implement javax.servlet.Filter
class HeaderFilter (Filter):
  def init(self, config):
      self.header = config.getInitParameter('header')

  def doFilter(self, request, response, chain):
      response.setHeader(self.header, "Yup")
      chain.doFilter(request, response)

web.xml:

<!-- Initialize the Jython runtime -->
  <listener>
      <listener-class>org.python.util.PyServletInitializer</listener-class>
      <load-on-startup>1</load-on-startup>
  </listener>

<!-- Declare a uniquely-named PyFilter -->
<filter>
 <filter-name>HeaderFilter</filter-name>
 <filter-class>org.python.util.PyFilter</filter-class>

 <!-- The special param __filter__ gives the context-relative path to the Jython source file -->
 <init-param>
   <param-name>__filter__</param-name>
   <param-value>/WEB-INF/pyfilter/HeaderFilter.py</param-value>
 </init-param>

 <!-- Other params are passed on the the Jython filter -->
 <init-param>
   <param-name>header</param-name>
   <param-value>X-LookMaNoJava</param-value>
 </init-param>
</filter>
<filter-mapping>
 <filter-name>HeaderFilter</filter-name>
 <url-pattern>/*</url-pattern>
</filter-mapping>

Field Summary

Modifier and Type	Field and Description
private Filter	cached
private FilterConfig	config
public static final String	FILTER_PATH_PARAM
private PythonInterpreter	interp
private long	loadedMtime
private File	source

Constructor Summary

Access	Constructor and Description
public	PyFilter()

Method Summary

Modifier and Type	Method and Description
public void	destroy() Overrides default javax.servlet.Filter.destroy. Called by the web container to indicate to a filter that it is being taken out of service.
public void	doFilter(ServletRequest the `ServletRequest` object contains the client's request request, ServletResponse the `ServletResponse` object contains the filter's response response, FilterChain the `FilterChain` for invoking the next filter or the resource chain) Implements javax.servlet.Filter.doFilter. The `doFilter` method of the Filter is called by the container each time a request/response pair is passed through the chain due to a client request for a resource at the end of the chain.
private Filter	getFilter()
private String	getRealPath(ServletContext context, String appPath)
public void	init(FilterConfig a `FilterConfig` object containing the filter's configuration and initialization parameters config) Overrides default javax.servlet.Filter.init. Called by the web container to indicate to a filter that it is being placed into service.
private Filter	loadFilter()

Inherited from java.lang.Object:: clone equals finalize getClass hashCode notify notifyAll toString wait wait wait

Field Detail

cached	back to summary
private Filter cached

config	back to summary
private FilterConfig config

FILTER_PATH_PARAM	back to summary
public static final String FILTER_PATH_PARAM

interp	back to summary
private PythonInterpreter interp

loadedMtime	back to summary
private long loadedMtime

source	back to summary
private File source

Constructor Detail

PyFilter	back to summary
public PyFilter()

Method Detail

destroy	back to summary
public void destroy() Overrides default javax.servlet.Filter.destroy. Doc from javax.servlet.Filter.destroy. Called by the web container to indicate to a filter that it is being taken out of service. This method is only called once all threads within the filter's doFilter method have exited or after a timeout period has passed. After the web container calls this method, it will not call the doFilter method again on this instance of the filter. This method gives the filter an opportunity to clean up any resources that are being held (for example, memory, file handles, threads) and make sure that any persistent state is synchronized with the filter's current state in memory.

destroy

back to summary

public void destroy()

Overrides default javax.servlet.Filter.destroy.

Doc from javax.servlet.Filter.destroy.

Called by the web container to indicate to a filter that it is being taken out of service.

This method is only called once all threads within the filter's doFilter method have exited or after a timeout period has passed. After the web container calls this method, it will not call the doFilter method again on this instance of the filter.

This method gives the filter an opportunity to clean up any resources that are being held (for example, memory, file handles, threads) and make sure that any persistent state is synchronized with the filter's current state in memory.

doFilter back to summary

doFilter	back to summary
public void doFilter(ServletRequest request, ServletResponse response, FilterChain chain) throws IOException, ServletException Implements javax.servlet.Filter.doFilter. Doc from javax.servlet.Filter.doFilter. The `doFilter` method of the Filter is called by the container each time a request/response pair is passed through the chain due to a client request for a resource at the end of the chain. The FilterChain passed in to this method allows the Filter to pass on the request and response to the next entity in the chain. A typical implementation of this method would follow the following pattern: Examine the request Optionally wrap the request object with a custom implementation to filter content or headers for input filtering Optionally wrap the response object with a custom implementation to filter content or headers for output filtering Either invoke the next entity in the chain using the FilterChain object (`chain.doFilter()`), or not pass on the request/response pair to the next entity in the filter chain to block the request processing Directly set headers on the response after invocation of the next entity in the filter chain. Parameters request:ServletRequest the `ServletRequest` object contains the client's request response:ServletResponse the `ServletResponse` object contains the filter's response chain:FilterChain the `FilterChain` for invoking the next filter or the resource Exceptions IOException: if an I/O related error has occurred during the processing ServletException: if an exception occurs that interferes with the filter's normal operation

public void doFilter(ServletRequest request, ServletResponse response, FilterChain chain) throws IOException, ServletException

Implements javax.servlet.Filter.doFilter.

Doc from javax.servlet.Filter.doFilter.

The doFilter method of the Filter is called by the container each time a request/response pair is passed through the chain due to a client request for a resource at the end of the chain. The FilterChain passed in to this method allows the Filter to pass on the request and response to the next entity in the chain.

A typical implementation of this method would follow the following pattern:

Examine the request
Optionally wrap the request object with a custom implementation to filter content or headers for input filtering
Optionally wrap the response object with a custom implementation to filter content or headers for output filtering
- Either invoke the next entity in the chain using the FilterChain object (chain.doFilter()),
- or not pass on the request/response pair to the next entity in the filter chain to block the request processing
Directly set headers on the response after invocation of the next entity in the filter chain.

Parameters

request:ServletRequest: the ServletRequest object contains the client's request
response:ServletResponse: the ServletResponse object contains the filter's response
chain:FilterChain: the FilterChain for invoking the next filter or the resource

Exceptions

IOException:: if an I/O related error has occurred during the processing
ServletException:: if an exception occurs that interferes with the filter's normal operation

getFilter	back to summary
private Filter getFilter() throws ServletException, IOException

getRealPath	back to summary
private String getRealPath(ServletContext context, String appPath)

init back to summary

init	back to summary
public void init(FilterConfig config) throws ServletException Overrides default javax.servlet.Filter.init. Doc from javax.servlet.Filter.init. Called by the web container to indicate to a filter that it is being placed into service. The servlet container calls the init method exactly once after instantiating the filter. The init method must complete successfully before the filter is asked to do any filtering work. The web container cannot place the filter into service if the init method either Throws a ServletException Does not return within a time period defined by the web container Parameters config:FilterConfig a `FilterConfig` object containing the filter's configuration and initialization parameters Exceptions ServletException: if an exception has occurred that interferes with the filter's normal operation

public void init(FilterConfig config) throws ServletException

Overrides default javax.servlet.Filter.init.

Doc from javax.servlet.Filter.init.

Called by the web container to indicate to a filter that it is being placed into service.

The servlet container calls the init method exactly once after instantiating the filter. The init method must complete successfully before the filter is asked to do any filtering work.

The web container cannot place the filter into service if the init method either

Throws a ServletException
Does not return within a time period defined by the web container