Module com.aoapps.servlet.util

Package com.aoapps.servlet.tomcat

Class GetWarFileFingerprint

java.lang.Object

jakarta.servlet.GenericServlet

jakarta.servlet.http.HttpServlet

com.aoapps.servlet.tomcat.GetWarFileFingerprint

All Implemented Interfaces:

Servlet, ServletConfig, Serializable

public class GetWarFileFingerprint
extends HttpServlet

Gets the WAR file MD5 fingerprint. This is used to verify the final deployed artifact matches the expected content.

We choose MD5 over SHA-256 because Jenkins uses MD5 for fingerprints. This allows to directly search and find exactly which build deployed the running application.

Find the WAR file based on the path the application is deployed to. Uses ServletContext.getRealPath("/") then appends ".war". This might be specific to Tomcat installations, and should not be assumed to apply generally.

See Also:

• Serialized Form

Field Summary

Fields inherited from class jakarta.servlet.http.HttpServlet

LEGACY_DO_HEAD

Constructor Summary

Constructors

Constructor	Description
GetWarFileFingerprint()

Method Summary

Modifier and Type	Method	Description
protected void	doGet(HttpServletRequest request, HttpServletResponse response)
static Optional<String>	getWarFileFingerprint(ServletContext context)	Computes the MD5 sum of the WAR file, located by using ServletContext.getRealPath("/") concatenated with WAR_EXTENSION.
void	init(ServletConfig config)

Methods inherited from class jakarta.servlet.http.HttpServlet

doDelete, doHead, doOptions, doPost, doPut, doTrace, getLastModified, service, service

Methods inherited from class jakarta.servlet.GenericServlet

destroy, getInitParameter, getInitParameterNames, getServletConfig, getServletContext, getServletInfo, getServletName, init, log, log

Methods inherited from class java.lang.Object

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

Constructor Details

GetWarFileFingerprint

public GetWarFileFingerprint()

Method Details

getWarFileFingerprint

public static Optional<String> getWarFileFingerprint(ServletContext context)

Computes the MD5 sum of the WAR file, located by using ServletContext.getRealPath("/") concatenated with WAR_EXTENSION.

If unable to find or compute, the specific reason is logged with level Level.WARNING or Level.SEVERE, depending on the nature of the failure. This method is not expected to be used frequently, only after deployments and possibly via occasional audit / monitoring. Logging of these messages is considered best from a security standpoint and are not expected to fill storage space significantly.

Returns:

The non-empty string of the WAR file fingerprint or Optional.empty() when unable to compute the fingerprint (in which case the underlying cause is logged).

init

public void init(ServletConfig config)
          throws ServletException

Specified by:

init in interface Servlet

Overrides:

init in class HttpServlet

Throws:

ServletException

doGet

protected void doGet(HttpServletRequest request,
 HttpServletResponse response)
              throws ServletException,
IOException

Overrides:

doGet in class HttpServlet

Throws:

ServletException

IOException