I am using GWT (2.5) with RPC, Spring and Postgresql for my project. My issue is about HttpSession handling .
All queries to server are dispatched by Spring (DispatchServlet) to my GwtController (extends RemoteServiceServlet) .
The particular RemoteService is injected in the GwtController . It is easy to get the HttpSession inside the GwtContorller.
In example by getThreadLocalRequest().getSession() or just from request.getSession().
My question is how to get HttpSession object inside the RemoteService ?
public class GwtRpcController extends RemoteServiceServlet {
……………
private RemoteService remoteService;
private Class remoteServiceClass;
………………
public ModelAndView handleRequest(HttpServletRequest arg0, HttpServletResponse arg1) throws Exception {
…………
}
public String processCall(String payload) throws SerializationException {
…………
}
public void setRemoteService(RemoteService remoteService) {
…………….
}
}
My Interface - DataService which implements RemoteService
public class DataServiceImpl implements DataService {
public Data getData(){
!!!!! Here I want to get HttpSession !!!!!
…………………………
}
}
You can maintain a ThreadLocal in your Servlet and store there your current Request, then expose your Request with a static method.
public class GwtRpcController extends RemoteServiceServlet {
static ThreadLocal<HttpServletRequest> perThreadRequest =
new ThreadLocal<HttpServletRequest>();
#Override
public String processCall(String payload) throws SerializationException {
try {
perThreadRequest.set(getThreadLocalRequest());
return super.processCall(payload);
} finally {
perThreadRequest.set(null);
}
}
public static HttpServletRequest getRequest() {
return perThreadRequest.get();
}
}
public class DataServiceImpl implements DataService {
public Data getData(){
HttpServletRequest request = GwtRpcController.getRequest();
HttpSession session = request.getSession();
}
}
Related
2 api's were exposed in a spring boot controller class. I have a requirement to intercept only 1 api and SHOULD NOT intercept other api. Can someone assist how to do this?
Below is the code
public class HeaderValidationInterceptor extends HandlerInterceptorAdapter{
private static final Logger logger = Logger.getLogger(HeaderValidationInterceptor.class);
//before the actual handler will be executed
public boolean preHandle(HttpServletRequest request,
HttpServletResponse response, Object handler)
throws Exception {
validateHeaderParam(request);
request.setAttribute("startTime", startTime);
return true;
}
}
Also I have a configuration class to add interceptor as below
Configuration
public class WebMvcConfig extends WebMvcConfigurerAdapter {
#Autowired
HeaderValidationInterceptor headerValidationInterceptor;
#Override
public void addInterceptors(InterceptorRegistry registry) {
registry.addInterceptor(headerValidationInterceptor)
}
}
Controller class
#RestController
public class MyController {
#Autowired
private ICityService cityService;
#GetMapping(value = "/cities")
public List<City> getCities() {
List<City> cities = cityService.findAll();
return cities;
}
#GetMapping(value = "/cities/{cityId}")
public City getCityById(#PathVariable("cityId") String cityId) {
City city = cityService.findCityById(cityId);
return cities;
}
}
Inside your interceptor, you can check the request URI for the endpoint you want to intercept.
You can use a regular expression to match the URI. Following for /cities/{cityId} endpoint.
if (request.getRequestURI().matches("(\\/cities\\/[a-zA-Z0-9]+\\/?)")) {
validateHeaderParam(request);
request.setAttribute("startTime", startTime);
}
I'm not sure what is that want to do in your interceptor, but for your example you can do this inside your controller as well. Like this,
#GetMapping(value = "/cities/{cityId}")
public City getCityById(#PathVariable("cityId") String cityId, HttpServletRequest request) {
// Here you can use HttpServletRequest and do your validation
// validateHeaderParam(request);
// request.setAttribute("startTime", startTime);
City city = cityService.findCityById(cityId);
return cities;
}
I have a spring-boot application without any controller classes.
How can I write exception handlers for this application. Exception handler classes annotated with #ControllerAdvice doesn't work.
If you are developing web applications, ErrroController is available.
#Controller
#RequestMapping("${server.error.path:${error.path:/error}}")
public class MyErrorController implements ErrorController {
private final ErrorAttributes errorAttributes;
public MyErrorController(final ErrorAttributes errorAttributes) {
this.errorAttributes = errorAttributes;
}
#Override
public String getErrorPath() {
return null;
}
#RequestMapping
public ResponseEntity<Map<String, Object>> error(final HttpServletRequest request) {
final WebRequest webRequest = new ServletWebRequest(request);
final Throwable th = errorAttributes.getError(webRequest);
// ...
// see also: BasicErrorController implementation
}
}
For learning purposes, I have made a custom authentication system where I pass a token from the client to the server through the Authorization header.
In the server side, I'd like to know if it's possible to create in the interceptor, before the request reaches a method in the controller, an User object with the email from the token as a property, and then pass this user object to every request where I require it.
This what I'd like to get, as an example:
#RestController
public class HelloController {
#RequestMapping("/")
public String index(final User user) {
return user.getEmail();
}
}
public class User {
private String email;
}
Where user is an object that I created in the pre-interceptor using the request Authorization header and then I can pass, or not, to any method in the RestController.
Is this possible?
#Recommended solution
I would create a #Bean with #Scope request which would hold the user and then put the appropriate entity into that holder and then take from that holder inside the method.
#Component
#Scope(value = "request", proxyMode = ScopedProxyMode.TARGET_CLASS)
public class CurrentUser {
private User currentUser;
public User getCurrentUser() {
return currentUser;
}
public void setCurrentUser(User currentUser) {
this.currentUser = currentUser;
}
}
and then
#Component
public class MyInterceptor implements HandlerInterceptor {
private CurrentUser currentUser;
#Autowired
MyInterceptor(CurrentUser currentUser) {
this.currentUser = currentUser;
}
#Override
public boolean preHandle(
HttpServletRequest request, HttpServletResponse response, Object handler) throws Exception {
this.currentUser.setCurrentUser(new User("whatever"));
return true;
}
}
and in the Controller
#RestController
public class HelloController {
private CurrentUser currentUser;
#Autowired
HelloController(CurrentUser currentUser) {
this.currentUser = currentUser;
}
#RequestMapping("/")
public String index() {
return currentUser.getCurrentUser().getEmail();
}
}
#Alternative solution
In case your object that you would like to have, only contains one field, you can just cheat on that and add that field to the HttpServletRequest parameters and just see the magic happen.
#Component
public class MyInterceptor implements HandlerInterceptor {
#Override
public boolean preHandle(
HttpServletRequest request, HttpServletResponse response, Object handler) throws Exception {
//TRY ONE AT THE TIME: email OR user
//BOTH SHOULD WORK BUT SEPARATELY OF COURSE
request.setAttribute("email", "login#domain.com");
request.setAttribute("user", new User("login#domain.com"));
return true;
}
}
You can use a local thread context object as follows - which will be handling one parameter per request thread (thread safe):
public abstract class LoggedUserContext {
private static ThreadLocal<User> currentLoggedUser = new ThreadLocal<>();
public static void setCurrentLoggedUser(User loggedUser) {
if (currentLoggedUser == null) {
currentLoggedUser = new ThreadLocal<>();
}
currentLoggedUser.set(loggedUser);
}
public static User getCurrentLoggedUser() {
return currentLoggedUser != null ? currentLoggedUser.get() : null;
}
public static void clear() {
if (currentLoggedUser != null) {
currentLoggedUser.remove();
}
}
}
Then in the interceptor prehandle function:
LoggedUserContext.setCurrentLoggedUser(loggedUser);
And in the interceptor postHandler function:
LoggedUserContext.clear();
From any other place:
User loggedUser = LoggedUserContext.getCurrentLoggedUser();
I'm trying to add a Filter that creates an object that is then to be used inside a controller in a Spring Boot application.
The idea is to use the Filter as a "centralized" generator of this object - that is request-specific and useful only in a controller.
I've tried to use the HttpServletRequest request.getSession().setAttribute method: I can access my object in the controller, but then it will be (clearly) added to the session.
Are the Filters the right way to do so? If yes, where can I keep the temporary object generated by the filter to be used by the controllers?
Why Don't you use a Bean with the #Scope('request')
#Component
#Scope(value="request", proxyMode= ScopedProxyMode.TARGET_CLASS)
class UserInfo {
public String getPassword() {
return password;
}
public void setPassword(String password) {
this.password = password;
}
private String password;
}
and then you can Autowireed this bean in both filter and controller to do setting and getting of data.
lifecycle of this UserInfo bean is only exisits within the request so once the http request is done then it terminates the instance as well
you can use ServletRequest.setAttribute(String name, Object o);
for example
#RestController
#EnableAutoConfiguration
public class App {
#RequestMapping("/")
public String index(HttpServletRequest httpServletRequest) {
return (String) httpServletRequest.getAttribute(MyFilter.passKey);
}
public static void main(String[] args) {
SpringApplication.run(App.class, args);
}
#Component
public static class MyFilter implements Filter {
public static String passKey = "passKey";
private static String passValue = "hello world";
#Override
public void init(FilterConfig filterConfig) throws ServletException {
}
#Override
public void doFilter(ServletRequest request, ServletResponse response, FilterChain chain)
throws IOException, ServletException {
request.setAttribute(passKey, passValue);
chain.doFilter(request, response);
}
#Override
public void destroy() {
}
}
}
An addition to wcong's answer.
Since Spring 4.3 after setting the attribute by using request.setAttribute(passKey, passValue);, you can access the attribute in your controller by simply annotating it with #RequestAttribute.
ex.
#RequestMapping("/")
public String index(#RequestAttribute passKey) {
return (String) passKey;
}
I dont know actually what is the scenario but If you really want to create an object in a filter and then use it somewhere in the code then you may use ThreadLocal class to do so.
To get know how this work see the most voted answer from that question Purpose of ThreadLocal?
In general using ThreadLocal you will be able to create a class that can store objects available ONLY for the current thread.
Sometimes for optimization reasons the same thread can be used to serve subsequent request as well so it will be nice to clean the threadLocal value after the request is processed.
class MyObjectStorage {
static private ThreadLocal threadLocal = new ThreadLocal<MyObject>();
static ThreadLocal<MyObject> getThreadLocal() {
return threadLocal;
}
}
in the filter
MyObjectStorage.getThreadLocal().set(myObject);
and in the Controller
MyObjectStorage.getThreadLocal().get();
Instead of filter you can use also #ControllerAdvice and pass objects to specified Controllers by using model.
#ControllerAdvice(assignableTypes={MyController.class})
class AddMyObjectAdvice {
// if you need request parameters
private #Inject HttpServletRequest request;
#ModelAttribute
public void addAttributes(Model model) {
model.addAttribute("myObject", myObject);
}
}
#Controller
public class MyController{
#RequestMapping(value = "/anyMethod", method = RequestMethod.POST)
public String anyMethod(Model model) {
MyObjecte myObject = model.getAttribute("myObject");
return "result";
}
}
I would like to create own class that will transform HTTP request and initializes object from this HTTP request in my Spring MVC application. I can create object by defining parameters in method but I need to do mapping in my own way and do it manually.
How can I do it with my own implementation that will pass to Spring and it will use it seamlessly?
Update1
Solution that kindly provided Bohuslav Burghardt doesn't work:
HTTP Status 500 - Request processing failed; nested exception is
java.lang.IllegalStateException: An Errors/BindingResult argument is
expected to be declared immediately after the model attribute, the
#RequestBody or the #RequestPart arguments to which they apply: public
java.lang.String
cz.deriva.derivis.api.oauth2.provider.controllers.OAuthController.authorize(api.oauth2.provider.domain.AuthorizationRequest,org.springframework.ui.Model,org.springframework.validation.BindingResult,javax.servlet.http.HttpServletRequest,javax.servlet.http.HttpServletResponse)
Maybe I should mention that I use own validator:
public class RequestValidator {
public boolean supports(Class clazz) {
return AuthorizationRequest.class.equals(clazz);
}
public void validate(Object obj, Errors e) {
AuthorizationRequest request = (AuthorizationRequest) obj;
if ("foobar".equals(request.getClientId())) {
e.reject("clientId", "nomatch");
}
}
}
and declaration of my method in controller (please not there is needed a validation - #Valid):
#RequestMapping(value = "/authorize", method = {RequestMethod.GET, RequestMethod.POST})
public String authorize(
#Valid AuthorizationRequest authorizationRequest,
BindingResult result
) {
}
I have two configurations classes in my application.
#Configuration
#EnableAutoConfiguration
#EnableWebMvc
#PropertySource("classpath:/jdbc.properties")
public class ApplicationConfig {
}
and
#Configuration
#EnableWebMvc
public class WebappConfig extends WebMvcConfigurerAdapter {
#Override
public void addArgumentResolvers(List<HandlerMethodArgumentResolver> argumentResolvers) {
argumentResolvers.add(new AuthorizationRequestArgumentResolver());
}
}
What is wrong?
Update 2
The problem is with param BindingResult result, when I remove it it works. But I need the result to process it when some errors occur.
If I understand your requirements correctly, you could implement custom HandlerMethodArgumentResolver for that purpose. See example below for implementation details:
Model object
public class AuthorizationRequestHolder {
#Valid
private AuthorizationRequest authorizationRequest;
private BindingResult bindingResult;
// Constructors, accessors omitted
}
Resolver
public class AuthorizationRequestMethodArgumentResolver implements HandlerMethodArgumentResolver {
#Override
public boolean supportsParameter(MethodParameter parameter) {
return AuthorizationRequestHolder.class.isAssignableFrom(parameter.getParameterType());
}
#Override
public Object resolveArgument(MethodParameter parameter,
ModelAndViewContainer mavContainer,
NativeWebRequest webRequest,
WebDataBinderFactory binderFactory) throws Exception {
HttpServletRequest request = (HttpServletRequest) webRequest.getNativeRequest();
// Map the authorization request
AuthorizationRequest authRequest = mapFromServletRequest(request);
AuthorizationRequestHolder authRequestHolder = new AuthorizationRequestHolder(authRequest);
// Validate the request
if (parameter.hasParameterAnnotation(Valid.class)) {
WebDataBinder binder = binderFactory.createBinder(webRequest, authRequestHolder, parameter.getParameterName());
binder.validate();
authRequestHolder.setBindingResult(binder.getBindingResult());
}
return authRequestHolder;
}
}
Configuration
#Configuration
#EnableWebMvc
public class WebappConfig extends WebMvcConfigurerAdapter {
#Override
public void addArgumentResolvers(List<HandlerMethodArgumentResolver> argumentResolvers) {
argumentResolvers.add(new AuthorizationRequestMethodArgumentResolver());
}
}
Usage
#RequestMapping("/auth")
public void doSomething(#Valid AuthRequestHolder authRequestHolder) {
if (authRequestHolder.getBindingResult().hasErrors()) {
// Process errors
}
AuthorizationRequest authRequest = authRequestHolder.getAuthRequest();
// Do something with the authorization request
}
Edit: Updated answer with workaround to non-supported usage of #Valid with HandlerMethodArgumentResolver parameters.