How to allow GET method for endpoint programmatically? - spring

Question

I am loading a .war file and add it as web app to the embedded Tomcat server.
#Bean
public EmbeddedServletContainerFactory servletContainerFactory() {
LOGGER.info("Adding web app");
return new TomcatEmbeddedServletContainerFactory() {
#Override
protected TomcatEmbeddedServletContainer getTomcatEmbeddedServletContainer(Tomcat tomcat) {
String appHome = System.getProperty(Environment.APP_HOME);
String targetFileName = "web-0.0.1-SNAPSHOT.war";
InputStream resourceAsStream = getClass().getClassLoader().getResourceAsStream(targetFileName);
LOGGER.info(System.getProperty("user.name"));
LOGGER.debug("Loading WAR from " + appHome);
File target = new File(Paths.get(appHome, targetFileName).toString());
try {
LOGGER.info(String.format("Copy %s to %s", targetFileName, target.getAbsoluteFile().toPath()));
java.nio.file.Files.copy(resourceAsStream, target.getAbsoluteFile().toPath(), StandardCopyOption.REPLACE_EXISTING);
Context context = tomcat.addWebapp("/", target.getAbsolutePath());
context.setParentClassLoader(getClass().getClassLoader());
} catch (ServletException ex) {
throw new IllegalStateException("Failed to add webapp.", ex);
} catch (Exception e) {
throw new IllegalStateException("Unknown error while trying to load webapp.", e);
}
return super.getTomcatEmbeddedServletContainer(tomcat);
}
};
}
This is working so far but if I access http://localhost:8080/web I am getting
2017-03-04 11:18:59.588 WARN 29234 --- [nio-8080-exec-2] o.s.web.servlet.PageNotFound : Request method 'GET' not supported
and the response
Allow: POST
Content-Length: 0
Date: Sat, 04 Mar 2017 10:26:16 GMT
I am sure all I have to do is to allow the GET method on /web and hopefully the static web content provided from the loaded war file will be accessible via web browser.
How/where can I configure the endpoint such that it allows GET requests?
I tried to introduce a WebController as described in this tutorial.
#Controller
public class WebController {
private final static Logger LOGGER = Logger.getLogger(WebController.class);
#RequestMapping(value = "/web", method = RequestMethod.GET)
public String index() {
LOGGER.info("INDEX !");
return "index";
}
}
In the log output I can see that this is getting mapped correctly:
RequestMappingHandlerMapping : Mapped "{[/web],methods=[GET]}" onto public java.lang.String org.ema.server.spring.controller.dl4j.WebController.index()
but it does not change the fact that I cannot visit the website.
I've also configured a InternalResourceViewResolver:
#Configuration
#EnableWebMvc
public class MvcConfiguration extends WebMvcConfigurerAdapter {
private final static Logger LOGGER = Logger.getLogger(MvcConfiguration.class);
#Override
public void configureViewResolvers(ViewResolverRegistry registry) {
LOGGER.info("configureViewResolvers()");
InternalResourceViewResolver resolver = new InternalResourceViewResolver();
resolver.setSuffix(".html");
registry.viewResolver(resolver);
}
#Override
public void configureDefaultServletHandling(
DefaultServletHandlerConfigurer configurer) {
configurer.enable();
}
}
web.xml
Since I configure everything in pure Java, this file does not define a lot:
<?xml version="1.0" encoding="UTF-8"?>
<web-app xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xmlns="http://java.sun.com/xml/ns/javaee"
xsi:schemaLocation="http://java.sun.com/xml/ns/javaee http://java.sun.com/xml/ns/javaee/web-app_3_0.xsd"
version="3.0">
<display-name>Easy Model Access Server</display-name>
<listener>
<listener-class>org.ema.server.ServerEntryPoint</listener-class>
</listener>
<context-param>
<param-name>log4j-config-location</param-name>
<param-value>WEB-INF/classes/log4j.properties</param-value>
</context-param>
<servlet-mapping>
<servlet-name>default</servlet-name>
<url-pattern>/web/*.html</url-pattern>
</servlet-mapping>
</web-app>
Reproduce
If you want to reproduce this you can simply checkout the entire code from github. All you need to do this:
mkdir ~/.ema
git clone https://github.com/silentsnooc/easy-model-access
cd easy-model-access/ema-server
mvn clean install
java -jar server/target/server-*.jar
This will clone, build and run the server.
The directory ~/.ema directory is required at the moment. It is where the WAR is being copied as the server starts.

Answer 1

My guess is that your web.xml maps any path to the Spring DispatcherServlet, something like:
<servlet>
<servlet-name>app</servlet-name>
<servlet-class>org.springframework.web.servlet.DispatcherServlet</servlet-class>
</servlet>
<servlet-mapping>
<servlet-name>app</servlet-name>
<url-pattern>/</url-pattern>
</servlet-mapping>
Because of <url-pattern>/</url-pattern> any request must be handled by a Spring controller, for this reason your static files are not served by Tomcat. Also a pattern like /*.html would have same effect.
If you have only a few pages you might add one or more mapping to the predefined default servlet for them, before the mapping of Spring (and also before Spring Security if you use it):
<servlet-mapping>
<servlet-name>default</servlet-name>
<url-pattern>index.html</url-pattern>
</servlet-mapping>
You may also use <url-pattern>*.html</url-pattern> or, if your resources are under the web path and there are only static resources there: <url-pattern>/web/*</url-pattern>
Maybe all this is done instead in Java code in the org.ema.server.ServerEntryPoint that you have as a listener in web.xml
I think the mapping I wrote up in web.xml is done in your case in method getServletMappings of class org.ema.server.spring.config.AppInitializer, I changed it to use a more strict pattern /rest-api/* instead than /, not sure pattern is correct and everything else works, but now http://127.0.0.1:8080/index.html works
#Override
protected String[] getServletMappings() {
return new String[] { "/rest-api/*" };
}

Answer 2

as I see the url: http://localhost:8080/web is wrong.
You can try: http://localhost:8080/[name-of-war-file]/web