SPR-5267: Support for PUT and DELETE in spring:form tag

git-svn-id: https://src.springframework.org/svn/spring-framework/trunk@283 50f2f4bb-b051-0410-bef5-90022cba6387

org.springframework.web/src/main/java/org/springframework/web/filter/HiddenHttpMethodFilter.java

@@ -0,0 +1,89 @@
+/*
+ * Copyright 2008 the original author or authors.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package org.springframework.web.filter;
+
+import java.io.IOException;
+import java.util.Locale;
+import javax.servlet.FilterChain;
+import javax.servlet.ServletException;
+import javax.servlet.http.HttpServletRequest;
+import javax.servlet.http.HttpServletRequestWrapper;
+import javax.servlet.http.HttpServletResponse;
+
+import org.springframework.util.Assert;
+import org.springframework.util.StringUtils;
+
+/**
+ * Servlet 2.3/2.4 {@link javax.servlet.Filter} that converts posted method parameters into HTTP methods, retrievable
+ * via {@link HttpServletRequest#getMethod()}. Since browsers currently only support GET and POST, a common technique -
+ * used by the Prototype library, for instance - is to use a normal POST with an additional hidden form field
+ * (<code>_method</code>) to pass the "real" HTTP method. This filter reads that parameter, and changes of {@link
+ * HttpServletRequestWrapper#getMethod()} accordingly.
+ *
+ * <p/>The name of the request parameter defaults to <code>_method</code>, but can be changed via the {@link
+ * #setMethodParam(String) methodParam} property.
+ *
+ * @author Arjen Poutsma
+ * @since 3.0
+ */
+public class HiddenHttpMethodFilter extends OncePerRequestFilter {
+
+	/** Default method parameter, i.e. <code>_method</code>. */
+	public static final String DEFAULT_METHOD_PARAM = "_method";
+
+	private String methodParam = DEFAULT_METHOD_PARAM;
+
+	/**
+	 * Set the parameter name to look for HTTP methods.
+	 *
+	 * @see #DEFAULT_METHOD_PARAM
+	 */
+	public void setMethodParam(String methodParam) {
+		Assert.hasText(methodParam, "'methodParam' must not be empty");
+		this.methodParam = methodParam;
+	}
+
+	protected void doFilterInternal(HttpServletRequest request, HttpServletResponse response, FilterChain filterChain)
+			throws ServletException, IOException {
+		if ("POST".equals(request.getMethod()) && StringUtils.hasLength(request.getParameter(methodParam))) {
+			String method = request.getParameter(methodParam).toUpperCase(Locale.ENGLISH);
+			HttpServletRequest wrapper = new HttpMethodRequestWrapper(method, request);
+			filterChain.doFilter(wrapper, response);
+		}
+		else {
+			filterChain.doFilter(request, response);
+		}
+	}
+
+	/**
+	 * Simple {@link HttpServletRequest} wrapper that returns the supplied method for {@link
+	 * HttpServletRequest#getMethod()}.
+	 */
+	private static class HttpMethodRequestWrapper extends HttpServletRequestWrapper {
+
+		private final String method;
+
+		private HttpMethodRequestWrapper(String method, HttpServletRequest request) {
+			super(request);
+			this.method = method;
+		}
+
+		public String getMethod() {
+			return method;
+		}
+	}
+}

org.springframework.web/src/test/java/org/springframework/web/filter/HiddenHttpMethodFilterTest.java

@@ -0,0 +1,73 @@
+/*
+ * Copyright ${YEAR} the original author or authors.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package org.springframework.web.filter;
+
+import java.io.IOException;
+import javax.servlet.FilterChain;
+import javax.servlet.ServletException;
+import javax.servlet.ServletRequest;
+import javax.servlet.ServletResponse;
+import javax.servlet.http.HttpServletRequest;
+
+import static org.junit.Assert.assertEquals;
+import org.junit.Before;
+import org.junit.Test;
+
+import org.springframework.mock.web.MockHttpServletRequest;
+import org.springframework.mock.web.MockHttpServletResponse;
+
+/** @author Arjen Poutsma */
+public class HiddenHttpMethodFilterTest {
+
+	private HiddenHttpMethodFilter filter;
+
+	@Before
+	public void createFilter() {
+		filter = new HiddenHttpMethodFilter();
+	}
+
+	@Test
+	public void filterWithParameter() throws IOException, ServletException {
+		MockHttpServletRequest request = new MockHttpServletRequest("POST", "/hotels");
+		request.addParameter("_method", "delete");
+		MockHttpServletResponse response = new MockHttpServletResponse();
+
+		FilterChain filterChain = new FilterChain() {
+
+			public void doFilter(ServletRequest filterRequest, ServletResponse filterResponse)
+					throws IOException, ServletException {
+				assertEquals("Invalid method", "DELETE", ((HttpServletRequest) filterRequest).getMethod());
+			}
+		};
+		filter.doFilter(request, response, filterChain);
+	}
+
+	@Test
+	public void filterWithNoParameter() throws IOException, ServletException {
+		MockHttpServletRequest request = new MockHttpServletRequest("POST", "/hotels");
+		MockHttpServletResponse response = new MockHttpServletResponse();
+
+		FilterChain filterChain = new FilterChain() {
+
+			public void doFilter(ServletRequest filterRequest, ServletResponse filterResponse)
+					throws IOException, ServletException {
+				assertEquals("Invalid method", "POST", ((HttpServletRequest) filterRequest).getMethod());
+			}
+		};
+		filter.doFilter(request, response, filterChain);
+	}
+}