PostReplaceFilter.java

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package com.sun.jersey.api.container.filter;

import com.sun.jersey.spi.container.ContainerRequest;
import com.sun.jersey.spi.container.ContainerRequestFilter;

/**
 * A filter to support HTTP method replacing of a POST request to a request 
 * utilizing another HTTP method for the case where proxies or HTTP
 * servers would otherwise block that HTTP method.
 * <p>
 * This filter may be used to replace a POST request with a PUT or DELETE
 * request.
 * <p>
 * Replacement will occur if the request method is POST and there exists an
 * a request header "X-HTTP-Method-Override" with a non-empty value. That value
 * will be the HTTP method that replaces the POST method.
 * <p>
 * When an application is deployed as a Servlet or Filter this Jersey filter can be
 * registered using the following initialization parameter:
 * <blockquote><pre>
 *     <init-param>
 *         <param-name>com.sun.jersey.spi.container.ContainerRequestFilters</param-name>
 *         <param-value>com.sun.jersey.api.container.filter.PostReplaceFilter</param-value>
 *     </init-param>
 * </pre></blockquote>
 * <p>
 * TODO support query parameter for declaring the replacing method.
 * 
 * @author Paul.Sandoz@Sun.Com
 * @see com.sun.jersey.api.container.filter
 */
public class PostReplaceFilter implements ContainerRequestFilter {

    public ContainerRequest filter(ContainerRequest request) {
        if (!request.getMethod().equalsIgnoreCase("POST"))
            return request;
        
        String override = request.getRequestHeaders().getFirst("X-HTTP-Method-Override");
        if (override == null)
            return request;        
        override = override.trim();
        if (override.length() == 0)
            return request;
        
        request.setMethod(override);
        return request;
    }
}