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SPR-5870 - Add support for content negotiation based on a request parameter value

This commit is contained in:
Arjen Poutsma 2009-07-13 09:44:07 +00:00
parent b1cb69fcb9
commit ff1dac8381
2 changed files with 84 additions and 11 deletions
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84
org.springframework.web.servlet/src/main/java/org/springframework/web/servlet/view/ContentNegotiatingViewResolver.java
View File

@ -56,19 +56,26 @@ import org.springframework.web.util.WebUtils;
*
* <p>The {@code ContentNegotiatingViewResolver} does not resolve views itself, but delegates to other {@link
* ViewResolver}s. By default, these other view resolvers are picked up automatically from the application context,
* though they can also be set explicitely by using the {@link #setViewResolvers(List) viewResolvers} property.
* though they can also be set explicitly by using the {@link #setViewResolvers(List) viewResolvers} property.
* <strong>Note</strong> that in order for this view resolver to work properly, the {@link #setOrder(int) order}
* property needs to be set to a higher precedence than the others (the default is {@link Ordered#HIGHEST_PRECEDENCE}.)
*
* <p>This view resolver uses the requested {@linkplain MediaType media type} to select a suitable {@link View} for a
* request. This media type is determined by using the following criteria: <ol> <li>If the requested path has a file
* extension and if the {@link #setFavorPathExtension(boolean)} property is <code>true</code>, the {@link
* #setMediaTypes(Map) mediaTypes} property is inspected for a matching media type.</li> <li>If there is no match and
* if the Java Activation Framework (JAF) is present on the class path, {@link FileTypeMap#getContentType(String)} is
* used.</li> <li>If the previous steps did not result in a media type, the request {@code Accept} header is used.</li>
* </ol> Once the requested media type has been determined, this resolver queries each delegate view resolver for a
* {@link View} and determines if the requested media type is {@linkplain MediaType#includes(MediaType) compatible} with
* the view's {@linkplain View#getContentType() content type}). The most compatible view is returned.
* request. This media type is determined by using the following criteria:
* <ol>
* <li>If the requested path has a file extension and if the {@link #setFavorPathExtension(boolean)} property is
* <code>true</code>, the {@link #setMediaTypes(Map) mediaTypes} property is inspected for a matching media type.</li>
* <li>If the request contains a parameter defining the extension and if the {@link #setFavorParameter(boolean)}
* property is <code>true</code>, the {@link #setMediaTypes(Map) mediaTypes} property is inspected for a matching media
* type. The default name of the parameter is <code>format</code> and it can be configured using the
* {@link #setParameterName(String) parameterName} property.</li>
* <li>If there is no match and if the Java Activation Framework (JAF) is present on the class path, {@link
* FileTypeMap#getContentType(String)} is used.</li>
* <li>If the previous steps did not result in a media type, the request {@code Accept} header is used.</li>
* </ol>
* Once the requested media type has been determined, this resolver queries each delegate view resolver for a
* {@link View} and determines if the requested media type is {@linkplain MediaType#includes(MediaType) compatible}
* with the view's {@linkplain View#getContentType() content type}). The most compatible view is returned.
*
* <p>For example, if the request path is {@code /view.html}, this view resolver will look for a view that has the
* {@code text/html} content type (based on the {@code html} file extension). A request for {@code /view} with a {@code
@ -78,7 +85,7 @@ import org.springframework.web.util.WebUtils;
* override the views provided by the view resolvers.
*
* @author Arjen Poutsma
* @author Jeremy Grelle
* @author Rostislav Hristov
* @see ViewResolver
* @see InternalResourceViewResolver
* @see BeanNameViewResolver
@ -95,6 +102,10 @@ public class ContentNegotiatingViewResolver extends WebApplicationObjectSupport
private boolean favorPathExtension = true;
private boolean favorParameter = false;
private String parameterName = "format";
private int order = Ordered.HIGHEST_PRECEDENCE;
private ConcurrentMap<String, MediaType> mediaTypes = new ConcurrentHashMap<String, MediaType>();
@ -113,7 +124,7 @@ public class ContentNegotiatingViewResolver extends WebApplicationObjectSupport
/**
* Indicates whether the extension of the request path should be used to determine the requested media type, in favor
* of looking at the {@code Accept} header.
* of looking at the {@code Accept} header. The default value is {@code true}.
*
* <p>For instance, when this flag is <code>true</code> (the default), a request for {@code /hotels.pdf} will result in
* an {@code AbstractPdfView} being resolved, while the {@code Accept} header can be the browser-defined {@code
@ -123,6 +134,26 @@ public class ContentNegotiatingViewResolver extends WebApplicationObjectSupport
this.favorPathExtension = favorPathExtension;
}
/**
* Indicates whether a request parameter should be used to determine the requested media type, in favor
* of looking at the {@code Accept} header. The default value is {@code false}.
*
* <p>For instance, when this flag is <code>true</code>, a request for {@code /hotels?format=pdf} will result in
* an {@code AbstractPdfView} being resolved, while the {@code Accept} header can be the browser-defined {@code
* text/html,application/xhtml+xml}.
*/
public void setFavorParameter(boolean favorParameter) {
this.favorParameter = favorParameter;
}
/**
* Sets the parameter name that can be used to determine the requested media type if the
* {@link #setFavorParameter(boolean)} property is {@code true}. The default parameter name is {@code format}.
*/
public void setParameterName(String parameterName) {
this.parameterName = parameterName;
}
/**
* Sets the mapping from file extensions to media types.
*
@ -200,6 +231,21 @@ public class ContentNegotiatingViewResolver extends WebApplicationObjectSupport
return mediaTypes;
}
}
if (favorParameter) {
if (request.getParameter(parameterName) != null) {
String parameterValue = request.getParameter(parameterName);
MediaType mediaType = getMediaTypeFromParameter(parameterValue);
if (mediaType != null) {
if (logger.isDebugEnabled()) {
logger.debug("Requested media type is '" + mediaType + "' (based on parameter '" +
parameterValue + "')");
}
List<MediaType> mediaTypes = new ArrayList<MediaType>();
mediaTypes.add(mediaType);
return mediaTypes;
}
}
}
String acceptHeader = request.getHeader(ACCEPT_HEADER);
if (StringUtils.hasText(acceptHeader)) {
List<MediaType> mediaTypes = MediaType.parseMediaTypes(acceptHeader);
@ -240,6 +286,22 @@ public class ContentNegotiatingViewResolver extends WebApplicationObjectSupport
}
return mediaType;
}
/**
* Determines the {@link MediaType} for the given parameter value.
*
* <p>The default implementation will check the {@linkplain #setMediaTypes(Map) media types} property for a
* defined mapping.
*
* <p>This method can be overriden to provide a different algorithm.
*
* @param parameterValue the parameter value (i.e. {@code pdf}).
* @return the media type, if any
*/
protected MediaType getMediaTypeFromParameter(String parameterValue) {
parameterValue = parameterValue.toLowerCase(Locale.ENGLISH);
return mediaTypes.get(parameterValue);
}
public View resolveViewName(String viewName, Locale locale) throws Exception {
RequestAttributes attrs = RequestContextHolder.getRequestAttributes();

11
org.springframework.web.servlet/src/test/java/org/springframework/web/servlet/view/ContentNegotiatingViewResolverTests.java
View File

@ -66,6 +66,17 @@ public class ContentNegotiatingViewResolverTests {
assertEquals("Invalid content type", Collections.singletonList(new MediaType("application", "xhtml+xml")),
result);
}
@Test
public void getMediaTypeParameter() {
viewResolver.setFavorParameter(true);
viewResolver.setMediaTypes(Collections.singletonMap("html", "application/xhtml+xml"));
MockHttpServletRequest request = new MockHttpServletRequest("GET", "/test");
request.addParameter("format", "html");
List<MediaType> result = viewResolver.getMediaTypes(request);
assertEquals("Invalid content type", Collections.singletonList(new MediaType("application", "xhtml+xml")),
result);
}
@Test
public void getMediaTypeAcceptHeader() {