# Class CrawlerSessionManagerValve

java.lang.Object
org.apache.catalina.util.LifecycleBase
org.apache.catalina.util.LifecycleMBeanBase
org.apache.catalina.valves.ValveBase
org.apache.catalina.valves.CrawlerSessionManagerValve

All Implemented Interfaces:
  `MBeanRegistration, Contained, JmxEnabled, Lifecycle, Valve`

public class CrawlerSessionManagerValve extends ValveBase
Web crawlers can trigger the creation of many thousands of sessions as they crawl a site which may result in significant memory consumption. This Valve ensures that crawlers are associated with a single session - just like normal users - regardless of whether or not they provide a session token with their requests.

- ## Nested Class Summary

  ### Nested classes/interfaces inherited from interface Lifecycle

  `Lifecycle.SingleUse`

- ## Field Summary

  ### Fields inherited from class ValveBase

  `asyncSupported, container, containerLog, next, sm`

  ### Fields inherited from interface Lifecycle

  `AFTER_DESTROY_EVENT, AFTER_INIT_EVENT, AFTER_START_EVENT, AFTER_STOP_EVENT, BEFORE_DESTROY_EVENT, BEFORE_INIT_EVENT, BEFORE_START_EVENT, BEFORE_STOP_EVENT, CONFIGURE_START_EVENT, CONFIGURE_STOP_EVENT, PERIODIC_EVENT, START_EVENT, STOP_EVENT`

- ## Constructor Summary

  Constructors
  Constructor
  Description
  `CrawlerSessionManagerValve()`
  Specifies a default constructor so async support can be configured.

- ## Method Summary

  Modifier and Type
  Method
  Description
  `Map<String,String>`
  `getClientIpSessionId()`
  Get the map of client identifiers to session IDs.
  `String`
  `getCrawlerIps()`
  Get the regular expression used to identify crawlers based on their IP address.
  `String`
  `getCrawlerUserAgents()`
  Get the regular expression used to identify crawlers based on the User-Agent header.
  `int`
  `getSessionInactiveInterval()`
  Get the session timeout for a crawler's session.
  `protected void`
  `initInternal()`
  Subclasses implement this method to perform any instance initialisation required.
  `void`
  `invoke(Request request, Response response)`
  Perform request processing as required by this Valve.
  `boolean`
  `isContextAware()`
  Determine whether the client identifier includes the context name.
  `boolean`
  `isHostAware()`
  Determine whether the client identifier includes the host name.
  `void`
  `setClientIdentifierFunction(Function<Request,String> clientIdentifierFunction)`
  Specify the clientIdentifier function that will be used to identify unique clients.
  `void`
  `setContextAware(boolean isContextAware)`
  Set whether the client identifier should include the context name.
  `void`
  `setCrawlerIps(String crawlerIps)`
  Specify the regular expression (using `Pattern`) that will be used to identify crawlers based on their IP address.
  `void`
  `setCrawlerUserAgents(String crawlerUserAgents)`
  Specify the regular expression (using `Pattern`) that will be used to identify crawlers based in the User-Agent header provided.
  `void`
  `setHostAware(boolean isHostAware)`
  Set whether the client identifier should include the host name.
  `void`
  `setSessionInactiveInterval(int sessionInactiveInterval)`
  Specify the session timeout (in seconds) for a crawler's session.

  ### Methods inherited from class ValveBase

  `backgroundProcess, getContainer, getDomainInternal, getNext, getObjectNameKeyProperties, isAsyncSupported, setAsyncSupported, setContainer, setNext, startInternal, stopInternal, toString`

  ### Methods inherited from class LifecycleMBeanBase

  `destroyInternal, getDomain, getObjectName, postDeregister, postRegister, preDeregister, preRegister, register, setDomain, unregister, unregister`

  ### Methods inherited from class LifecycleBase

  `addLifecycleListener, destroy, findLifecycleListeners, fireLifecycleEvent, getState, getStateName, getThrowOnFailure, init, removeLifecycleListener, setState, setState, setThrowOnFailure, start, stop`

  ### Methods inherited from class Object

  `clone, equals, finalize, getClass, hashCode, notify, notifyAll, wait, wait, wait`

- ## Constructor Details

  - ### CrawlerSessionManagerValve

    public CrawlerSessionManagerValve()
    Specifies a default constructor so async support can be configured.

- ## Method Details

  - ### setCrawlerUserAgents

    public void setCrawlerUserAgents(String crawlerUserAgents)
    Specify the regular expression (using `Pattern`) that will be used to identify crawlers based in the User-Agent header provided. The default is ".*GoogleBot.*|.*bingbot.*|.*Yahoo! Slurp.*"
    Parameters:
      `crawlerUserAgents` - The regular expression using `Pattern`

  - ### getCrawlerUserAgents

    public String getCrawlerUserAgents()
    Get the regular expression used to identify crawlers based on the User-Agent header.
    Returns:
      The current regular expression being used to match user agents
    See Also:
      - `setCrawlerUserAgents(String)`

  - ### setCrawlerIps

    public void setCrawlerIps(String crawlerIps)
    Specify the regular expression (using `Pattern`) that will be used to identify crawlers based on their IP address. The default is no crawler IPs.
    Parameters:
      `crawlerIps` - The regular expression using `Pattern`

  - ### getCrawlerIps

    public String getCrawlerIps()
    Get the regular expression used to identify crawlers based on their IP address.
    Returns:
      The current regular expression being used to match IP addresses
    See Also:
      - `setCrawlerIps(String)`

  - ### setSessionInactiveInterval

    public void setSessionInactiveInterval(int sessionInactiveInterval)
    Specify the session timeout (in seconds) for a crawler's session. This is typically lower than that for a user session. The default is 60 seconds.
    Parameters:
      `sessionInactiveInterval` - The new timeout for crawler sessions

  - ### getSessionInactiveInterval

    public int getSessionInactiveInterval()
    Get the session timeout for a crawler's session.
    Returns:
      The current timeout in seconds
    See Also:
      - `setSessionInactiveInterval(int)`

  - ### getClientIpSessionId

    public Map<String,String> getClientIpSessionId()
    Get the map of client identifiers to session IDs.
    Returns:
      The map of client identifiers to session IDs

  - ### isHostAware

    public boolean isHostAware()
    Determine whether the client identifier includes the host name.
    Returns:
      `true` if the client identifier includes the host name

  - ### setHostAware

    public void setHostAware(boolean isHostAware)
    Set whether the client identifier should include the host name.
    Parameters:
      `isHostAware` - `true` if the client identifier should include the host name

  - ### isContextAware

    public boolean isContextAware()
    Determine whether the client identifier includes the context name.
    Returns:
      `true` if the client identifier includes the context name

  - ### setContextAware

    public void setContextAware(boolean isContextAware)
    Set whether the client identifier should include the context name.
    Parameters:
      `isContextAware` - `true` if the client identifier should include the context name

  - ### setClientIdentifierFunction

    public void setClientIdentifierFunction(Function<Request,String> clientIdentifierFunction)
    Specify the clientIdentifier function that will be used to identify unique clients. The default is to use the client IP address, optionally combined with the host name and context name.
    Parameters:
      `clientIdentifierFunction` - The new function used to build identifiers for clients.

  - ### initInternal

    protected void initInternal() throws LifecycleException
    Description copied from class: `LifecycleBase`
    Subclasses implement this method to perform any instance initialisation required.
    Overrides:
      `initInternal` in class `ValveBase`
    Throws:
      `LifecycleException` - If the initialisation fails

  - ### invoke

    public void invoke(Request request, Response response) throws IOException, ServletException
    Description copied from interface: `Valve`

    Perform request processing as required by this Valve.

    An individual Valve MAY perform the following actions, in the specified order:

    - Examine and/or modify the properties of the specified Request and Response.
    - Examine the properties of the specified Request, completely generate the corresponding Response, and return control to the caller.
    - Examine the properties of the specified Request and Response, wrap either or both of these objects to supplement their functionality, and pass them on.
    - If the corresponding Response was not generated (and control was not returned), call the next Valve in the pipeline (if there is one) by executing `getNext().invoke()`.
    - Examine, but not modify, the properties of the resulting Response (which was created by a subsequently invoked Valve or Container).

    A Valve MUST NOT do any of the following things:

    - Change request properties that have already been used to direct the flow of processing control for this request (for instance, trying to change the virtual host to which a Request should be sent from a pipeline attached to a Host or Context in the standard implementation).
    - Create a completed Response AND pass this Request and Response on to the next Valve in the pipeline.
    - Consume bytes from the input stream associated with the Request, unless it is completely generating the response, or wrapping the request before passing it on.
    - Modify the HTTP headers included with the Response after the `getNext().invoke()` method has returned.
    - Perform any actions on the output stream associated with the specified Response after the `getNext().invoke()` method has returned.
    Parameters:
      `request` - The servlet request to be processed
      `response` - The servlet response to be created
    Throws:
      `IOException` - if an input/output error occurs, or is thrown by a subsequently invoked Valve, Filter, or Servlet
      `ServletException` - if a servlet error occurs, or is thrown by a subsequently invoked Valve, Filter, or Servlet