tap.resource

Class ForwardResource

java.lang.Object

tap.resource.ForwardResource

All Implemented Interfaces:

TAPResource

Direct Known Subclasses:

Examples, HomePage

public abstract class ForwardResource
extends java.lang.Object
implements TAPResource

A TAPResource which is able to "forward" an HTTP request toward a specified URI.

In function of the URI shape (i.e. what is the scheme? none/file:/other) and the servlet path, the HTTP request will be internally forwarded to the Web Application file (using RequestDispatcher.forward(javax.servlet.ServletRequest, javax.servlet.ServletResponse)), the content of the specified file will be copied in the HTTP response or a redirection toward the given URL will be performed.

See forward(String, String, HttpServletRequest, HttpServletResponse) for more details

Since:

2.1

Version:

2.3 (03/2019)

Author:

Grégory Mantelet (ARI;CDS)

Field Summary

Fields

Modifier and Type	Field and Description
protected TAPLog	logger Logger that forward(String, String, HttpServletRequest, HttpServletResponse) must use in case of not grave error (e.g.

Constructor Summary

Constructors

Modifier	Constructor and Description
protected	ForwardResource(TAPLog logger) Builds a ForwardResource with a logger to use in case of "small" errors.

Method Summary

Modifier and Type	Method and Description
boolean	forward(java.lang.String file, java.lang.String mimeType, javax.servlet.http.HttpServletRequest request, javax.servlet.http.HttpServletResponse response) Write the content of the specified file in the given HTTP response.
protected void	logError(java.lang.String message, java.lang.Throwable error, java.lang.String file) Log the given error as a TAP log message with the UWSLog.LogLevel ERROR, and the event corresponding to the resource name.

Methods inherited from class java.lang.Object

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

Methods inherited from interface tap.resource.TAPResource

destroy, executeResource, getName, init, setTAPBaseURL

Field Detail

logger

protected final TAPLog logger

Logger that forward(String, String, HttpServletRequest, HttpServletResponse) must use in case of not grave error (e.g. the specified Web Application file can not be found).

Constructor Detail

ForwardResource

protected ForwardResource(TAPLog logger)

Builds a ForwardResource with a logger to use in case of "small" errors.

Parameters:

logger - A TAP logger.

Method Detail

forward

public final boolean forward(java.lang.String file,
                             java.lang.String mimeType,
                             javax.servlet.http.HttpServletRequest request,
                             javax.servlet.http.HttpServletResponse response)
                      throws java.io.IOException

Write the content of the specified file in the given HTTP response.

Three cases are taken into account in this function, in function of the given URI:

1. a file inside WebContent if the given URI has no scheme (e.g. "tapIndex.jsp" or "/myFiles/tapIndex.html"). The URI is then an absolute (if starting with "/") or a relative path to file inside the WebContent directory. In this case the request is forwarded to this file. It is neither a redirection nor a copy, but a kind of inclusion of the interpreted file into the response. This method MUST be used if your page/content is a JSP.
2. a local file if a URI starts with "file:". In this case, the content of the local file is copied in the HTTP response. There is no interpretation. So this method should not be used for JSP.
3. a distance document in all other cases. Indeed, if there is a scheme different from "file:" the given URI will be considered as a URL. In this case, any request to the TAP home page is redirected to this URL.

Important note: The 1st option is applied ONLY IF the path of the TAP servlet is NOT the root path of the web application: that's to say /*. In the case where a URI without scheme is provided though the servlet path is /*, this function will resolve the full path on the local file system and apply the 2nd option: write the file content directly in the response. Note that will work only in cases where the specified file is not a JSP or does not need any kind of interpretation by the function RequestDispatcher.forward(javax.servlet.ServletRequest, javax.servlet.ServletResponse).

Parameters:

file - URI/URL/path of the file to write/forward/redirect in the given HTTP response.

mimeType - MIME type of the specified file.

request - HTTP request which require the specified file.

response - HTTP response in which the specified file must be written/forwarded/redirected.

Returns:

true if the forward/redirection was successful, false otherwise.

Throws:

java.io.IOException - When an error occur while forwarding toward the specified Web application resource, or while writing the specified local file or while redirection toward the specified URL or when the HTTP connection has been aborted.

java.lang.IllegalStateException - If an attempt of resetting the buffer fails.

logError

protected void logError(java.lang.String message,
                        java.lang.Throwable error,
                        java.lang.String file)

Log the given error as a TAP log message with the UWSLog.LogLevel ERROR, and the event corresponding to the resource name.

The logged message starts with: Can not write the specified content ({file}). After the specified error message, the following is appended: ! => A default content may be displayed..

If the message parameter is missing, the Throwable message will be taken instead. And if this latter is also missing, none will be written.

Parameters:

message - Error message to log.

error - The exception at the origin of the error.