org.xins.server.StandardCallingConvention Maven / Gradle / Ivy
/*
* $Id: StandardCallingConvention.java,v 1.72 2011/02/19 08:48:28 agoubard Exp $
*
* See the COPYRIGHT file for redistribution and use restrictions.
*/
package org.xins.server;
import java.io.IOException;
import java.io.StringWriter;
import java.io.Writer;
import java.util.HashMap;
import java.util.Map;
import org.w3c.dom.Element;
import org.xml.sax.SAXException;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import org.xins.common.text.TextUtils;
import org.xins.common.xml.ElementFormatter;
/**
* Standard calling convention. The technical name for this calling convention
* is _xins-std.
*
* @version $Revision: 1.72 $ $Date: 2011/02/19 08:48:28 $
* @author Anthony Goubard
* @author Ernst de Haan
*/
public class StandardCallingConvention extends CallingConvention {
/**
* The response encoding format.
*/
protected static final String RESPONSE_ENCODING = "UTF-8";
/**
* The content type of the HTTP response.
*/
protected static final String RESPONSE_CONTENT_TYPE = "text/xml; charset=" + RESPONSE_ENCODING;
/**
* Checks if the specified request can be handled by this calling
* convention.
*
* This method will not throw any exception.
*
* @param httpRequest
* the HTTP request to investigate, cannot be null.
*
* @return
* true if this calling convention is possibly
* able to handle this request, or false if it
* definitely not able to handle this request.
*/
protected boolean matches(HttpServletRequest httpRequest) {
// If no _function parameter is specified, then there is no match
return ! TextUtils.isEmpty(httpRequest.getParameter("_function"));
}
/**
* Converts an HTTP request to a XINS request (implementation method). This
* method should only be called from class CallingConvention. Only
* then it is guaranteed that the httpRequest argument is not
* null.
*
* @param httpRequest
* the HTTP request, will not be null.
*
* @return
* the XINS request object, never null.
*
* @throws InvalidRequestException
* if the request is considerd to be invalid.
*
* @throws FunctionNotSpecifiedException
* if the request does not indicate the name of the function to execute.
*/
protected FunctionRequest convertRequestImpl(HttpServletRequest httpRequest)
throws InvalidRequestException,
FunctionNotSpecifiedException {
// Parse the parameters in the HTTP request
Map params = gatherParams(httpRequest);
// Remove all invalid parameters
cleanUpParameters(params);
// Determine function name
String functionName = httpRequest.getParameter("_function");
if (TextUtils.isEmpty(functionName)) {
throw new FunctionNotSpecifiedException();
}
// Get data section
String dataSectionValue = httpRequest.getParameter("_data");
Element dataElement = null;
if (dataSectionValue != null && dataSectionValue.length() > 0) {
// Parse the data section
try {
dataElement = ElementFormatter.parse(dataSectionValue);
// Parsing error
} catch (SAXException exception) {
String detail = "Cannot parse the data section.";
throw new InvalidRequestException(detail, exception);
}
}
// Define the HTTP method in the backpack
Map backpack = new HashMap();
backpack.put("_httpMethod", httpRequest.getMethod());
// Construct and return the request object
return new FunctionRequest(functionName, params, dataElement, backpack);
}
/**
* Converts a XINS result to an HTTP response (implementation method).
*
* @param xinsResult
* the XINS result object that should be converted to an HTTP response,
* will not be null.
*
* @param httpResponse
* the HTTP response object to configure, will not be null.
*
* @param httpRequest
* the HTTP request, will not be null.
*
* @throws IOException
* if calling any of the methods in httpResponse causes an
* I/O error.
*/
protected void convertResultImpl(FunctionResult xinsResult,
HttpServletResponse httpResponse,
Map backpack)
throws IOException {
// Set the status code and the content type
httpResponse.setStatus(HttpServletResponse.SC_OK);
httpResponse.setContentType(RESPONSE_CONTENT_TYPE);
// Determine the method
String method = (String) backpack.get("_httpMethod");
// Handle HEAD requests
if ("HEAD".equals(method)) {
StringWriter out = new StringWriter();
CallResultOutputter.output(out, xinsResult);
httpResponse.setContentLength(out.getBuffer().length());
// Handle non-HEAD requests
} else {
Writer out = httpResponse.getWriter();
CallResultOutputter.output(out, xinsResult);
out.close();
}
}
}