com.google.gwt.user.server.rpc
Class RPCServletUtils

java.lang.Object
  com.google.gwt.user.server.rpc.RPCServletUtils

public class RPCServletUtils
extends java.lang.Object

Utility class containing helper methods used by servlets that integrate with the RPC system.

acceptsGzipEncoding

public static boolean acceptsGzipEncoding(javax.servlet.http.HttpServletRequest request)

Returns true if the HttpServletRequest accepts Gzip encoding. This is done by checking that the accept-encoding header specifies gzip as a supported encoding.

Parameters:

request - the request instance to test for gzip encoding acceptance

Returns:

true if the HttpServletRequest accepts Gzip encoding

exceedsUncompressedContentLengthLimit

public static boolean exceedsUncompressedContentLengthLimit(java.lang.String content)

Returns true if the response content's estimated UTF-8 byte length exceeds 256 bytes.

Parameters:

content - the contents of the response

Returns:

true if the response content's estimated UTF-8 byte length exceeds 256 bytes

isExpectedException

public static boolean isExpectedException(java.lang.reflect.Method serviceIntfMethod,
                                          java.lang.Throwable cause)

Returns true if the Method definition on the service is specified to throw the exception contained in the InvocationTargetException or false otherwise. NOTE we do not check that the type is serializable here. We assume that it must be otherwise the application would never have been allowed to run.

Parameters:

serviceIntfMethod - the method from the RPC request

cause - the exception that the method threw

Returns:

true if the exception's type is in the method's signature

readContentAsUtf8

public static java.lang.String readContentAsUtf8(javax.servlet.http.HttpServletRequest request)
                                          throws java.io.IOException,
                                                 javax.servlet.ServletException

Returns the content of an HttpServletRequest by decoding it using the UTF-8 charset.

Parameters:

request - the servlet request whose content we want to read

Returns:

the content of an HttpServletRequest by decoding it using the UTF-8 charset

Throws:

java.io.IOException - if the requests input stream cannot be accessed, read from or closed

javax.servlet.ServletException - if the content length of the request is not specified of if the request's content type is not 'text/x-gwt-rpc' and 'charset=utf-8'

readContentAsUtf8

public static java.lang.String readContentAsUtf8(javax.servlet.http.HttpServletRequest request,
                                                 boolean checkHeaders)
                                          throws java.io.IOException,
                                                 javax.servlet.ServletException

Returns the content of an HttpServletRequest by decoding it using the UTF-8 charset.

Parameters:

request - the servlet request whose content we want to read

checkHeaders - Specify 'true' to check the Content-Type header to see that it matches the expected value 'text/x-gwt-rpc' and the content encoding is UTF-8. Disabling this check may allow some types of cross type security attacks.

Returns:

the content of an HttpServletRequest by decoding it using the UTF-8 charset

Throws:

java.io.IOException - if the requests input stream cannot be accessed, read from or closed

javax.servlet.ServletException - if the content length of the request is not specified of if the request's content type is not 'text/x-gwt-rpc' and 'charset=utf-8'

setGzipEncodingHeader

public static void setGzipEncodingHeader(javax.servlet.http.HttpServletResponse response)

Sets the correct header to indicate that a response is gzipped.

shouldGzipResponseContent

public static boolean shouldGzipResponseContent(javax.servlet.http.HttpServletRequest request,
                                                java.lang.String responseContent)

Returns true if the request accepts gzip encoding and the the response content's estimated UTF-8 byte length exceeds 256 bytes.

Parameters:

request - the request associated with the response content

responseContent - a string that will be

Returns:

true if the request accepts gzip encoding and the the response content's estimated UTF-8 byte length exceeds 256 bytes

writeResponse

public static void writeResponse(javax.servlet.ServletContext servletContext,
                                 javax.servlet.http.HttpServletResponse response,
                                 java.lang.String responseContent,
                                 boolean gzipResponse)
                          throws java.io.IOException

Write the response content into the HttpServletResponse. If gzipResponse is true, the response content will be gzipped prior to being written into the response.

Parameters:

servletContext - servlet context for this response

response - response instance

responseContent - a string containing the response content

gzipResponse - if true the response content will be gzip encoded before being written into the response

Throws:

java.io.IOException - if reading, writing, or closing the response's output stream fails

writeResponseForUnexpectedFailure

public static void writeResponseForUnexpectedFailure(javax.servlet.ServletContext servletContext,
                                                     javax.servlet.http.HttpServletResponse response,
                                                     java.lang.Throwable failure)

Called when the servlet itself has a problem, rather than the invoked third-party method. It writes a simple 500 message back to the client.

Parameters:

servletContext -

response -

failure -