Moved REST HTTP Method Conversion to View chapter.
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Arjen Poutsma
parent
06777c8123
commit
e9ac4bc0ad
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@ -38,50 +38,6 @@
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configuration</link> to understand the general programming model.</para>
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</section>
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<section id="rest-method-conversion">
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<title>HTTP Method Conversion</title>
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<para>A key principle of REST is the use of the Uniform Interface. This
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means that all resources (URLs) can be manipulated using the same four
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HTTP methods: GET, PUT, POST, and DELETE. For each methods, the HTTP
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specification defines the exact semantics. For instance, a GET should
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always be a safe operation, meaning that is has no side effects, and a
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PUT or DELETE should be idempotent, meaning that you can repeat these
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operations over and over again, but the end result should be the same.
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While HTTP defines these four methods, HTML only supports two: GET and
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POST. Fortunately, there are two possible workarounds: you can either
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use JavaScript to do your PUT or DELETE, or simply do a POST with the
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'real' method as an additional parameter (modeled as a hidden input
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field in an HTML form). This latter trick is what Spring's
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<classname>HiddenHttpMethodFilter</classname> does. This filter is a
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plain Servlet Filter and therefore it can be used in combination with
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any web framework (not just Spring MVC). Simply add this filter to your
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web.xml, and a POST with a hidden _method parameter will be converted
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into the corresponding HTTP method request.</para>
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<section id="rest-form-tags">
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<title>Supporting Spring form tags</title>
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<para>To support HTTP method conversion the Spring MVC form tag was
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updated to support setting the HTTP method. For example, the following
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snippet taken from the updated Petclinic sample</para>
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<programlisting language="xml"><form:form method="delete">
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<p class="submit"><input type="submit" value="Delete Pet"/></p>
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</form:form></programlisting>
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<para>This will actually perform an HTTP POST, with the 'real' DELETE
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method hidden behind a request parameter, to be picked up by the
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<classname>HiddenHttpMethodFilter</classname>. The corresponding
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@Controller method is shown below</para>
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<programlisting language="java">@RequestMapping(method = RequestMethod.DELETE)
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public String deletePet(@PathVariable int ownerId, @PathVariable int petId) {
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this.clinic.deletePet(petId);
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return "redirect:/owners/" + ownerId;
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}</programlisting>
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</section>
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</section>
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<section id="rest-etag">
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<title>ETag support</title>
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@ -737,6 +737,57 @@ productList.url=/WEB-INF/jsp/productlist.jsp</programlisting>
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</tr>
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</form></programlisting>
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</section>
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<section id="rest-method-conversion">
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<title>HTTP Method Conversion</title>
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<para>A key principle of REST is the use of the Uniform Interface.
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This means that all resources (URLs) can be manipulated using the same
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four HTTP methods: GET, PUT, POST, and DELETE. For each methods, the
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HTTP specification defines the exact semantics. For instance, a GET
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should always be a safe operation, meaning that is has no side
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effects, and a PUT or DELETE should be idempotent, meaning that you
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can repeat these operations over and over again, but the end result
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should be the same. While HTTP defines these four methods, HTML only
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supports two: GET and POST. Fortunately, there are two possible
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workarounds: you can either use JavaScript to do your PUT or DELETE,
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or simply do a POST with the 'real' method as an additional parameter
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(modeled as a hidden input field in an HTML form). This latter trick
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is what Spring's <classname>HiddenHttpMethodFilter</classname> does.
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This filter is a plain Servlet Filter and therefore it can be used in
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combination with any web framework (not just Spring MVC). Simply add
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this filter to your web.xml, and a POST with a hidden _method
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parameter will be converted into the corresponding HTTP method
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request.</para>
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<para>To support HTTP method conversion the Spring MVC form tag was
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updated to support setting the HTTP method. For example, the following
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snippet taken from the updated Petclinic sample</para>
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<programlisting language="xml"><form:form method="delete">
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<p class="submit"><input type="submit" value="Delete Pet"/></p>
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</form:form></programlisting>
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<para>This will actually perform an HTTP POST, with the 'real' DELETE
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method hidden behind a request parameter, to be picked up by the
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<classname>HiddenHttpMethodFilter</classname>, as defined in web.xml:</para>
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<programlisting language="java"><filter>
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<filter-name>httpMethodFilter</filter-name>
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<filter-class>org.springframework.web.filter.HiddenHttpMethodFilter</filter-class>
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</filter>
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<filter-mapping>
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<filter-name>httpMethodFilter</filter-name>
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<servlet-name>petclinic</servlet-name>
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</filter-mapping></programlisting><para>The corresponding @Controller method
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is shown below:</para>
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<programlisting language="java">@RequestMapping(method = RequestMethod.DELETE)
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public String deletePet(@PathVariable int ownerId, @PathVariable int petId) {
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this.clinic.deletePet(petId);
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return "redirect:/owners/" + ownerId;
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}</programlisting>
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</section>
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</section>
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</section>
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@ -2435,7 +2486,7 @@ simpleReport.reportDataKey=myBeanData</programlisting>
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</section>
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</section>
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<section id="rest-feedview">
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<section id="view-feeds">
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<title>Feed Views</title>
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<para>Both <classname>AbstractAtomFeedView</classname> and
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