Can't understand `#Autowired HttpServletRequest` of spring-mvc well - spring

In our spring application, we use HttpServletRequest in two ways:
(the code here are simplied, and seems meaningless)
In the controller:
#RequestMapping(value = "/hello", method = RequestMethod.GET)
#ResponseBody
public ResponseEntity<String> hello(HttpServletRequest request) {
System.out.println("## controller req.hashcode: " + request.hashCode());
System.out.println("## header 'abc': " + request.getHeader("abc"));
return new ResponseEntity<String>("OK", HttpStatus.OK);
}
In a normal component:
#Component
class RequestService {
private final HttpServletRequest request;
#Autowired
public RequestService(HttpServletRequest request) {
this.request = request;
}
public String getHeaderAbc() {
System.out.println("## service req.hashcode: " + request.hashCode());
return this.request.getHeader("abc");
}
}
At first, I was thinking the 2nd way is totally wrong, because it should only inject the request instance once. So no matter when I invoke getHeaderAbc() method, it should return the same value(of the first request).
But when I try it, I found several interesting things:
The request.hashCode() in controller is always different (as I expected)
The request.hashCode() in RequestService is always the same (as I thought)
But the header value is different if I issue a request with a different header abc !!!
It seems for the singleton RequestService, spring keeps the request instance, but changed the headers it contains!
How to understand it?

Take a look at the scoped proxy. http://www.java-allandsundry.com/2012/08/spring-scoped-proxy.html
Basically you inject a proxy that keeps a references to the current HttpRequest beans and gives you the right one, selecting it by the request id.
IMHO using HttpRequest outside of the web layer is not a good practice. I would use it only in the controlellrs.

Related

Content type 'application/x-www-form-urlencoded;charset=UTF-8' not supported for #RequestBody MultiValueMap

Based on the answer for problem with x-www-form-urlencoded with Spring #Controller
I have written the below #Controller method
#RequestMapping(value = "/{email}/authenticate", method = RequestMethod.POST
, produces = {"application/json", "application/xml"}
, consumes = {"application/x-www-form-urlencoded"}
)
public
#ResponseBody
Representation authenticate(#PathVariable("email") String anEmailAddress,
#RequestBody MultiValueMap paramMap)
throws Exception {
if(paramMap == null || paramMap.get("password") == null) {
throw new IllegalArgumentException("Password not provided");
}
}
the request to which fails with the below error
{
"timestamp": 1447911866786,
"status": 415,
"error": "Unsupported Media Type",
"exception": "org.springframework.web.HttpMediaTypeNotSupportedException",
"message": "Content type 'application/x-www-form-urlencoded;charset=UTF-8' not supported",
"path": "/users/usermail%40gmail.com/authenticate"
}
[PS: Jersey was far more friendly, but couldn't use it now given the practical restrictions here]
The problem is that when we use application/x-www-form-urlencoded, Spring doesn't understand it as a RequestBody. So, if we want to use this
we must remove the #RequestBody annotation.
Then try the following:
#RequestMapping(
path = "/{email}/authenticate",
method = RequestMethod.POST,
consumes = MediaType.APPLICATION_FORM_URLENCODED_VALUE,
produces = {
MediaType.APPLICATION_ATOM_XML_VALUE,
MediaType.APPLICATION_JSON_VALUE
})
public #ResponseBody Representation authenticate(
#PathVariable("email") String anEmailAddress,
MultiValueMap paramMap) throws Exception {
if (paramMap == null &&
paramMap.get("password") == null) {
throw new IllegalArgumentException("Password not provided");
}
return null;
}
Note that removed the annotation #RequestBody
answer: Http Post request with content type application/x-www-form-urlencoded not working in Spring
It seems that now you can just mark the method parameter with #RequestParam and it will do the job for you.
#PostMapping( "some/request/path" )
public void someControllerMethod( #RequestParam Map<String, String> body ) {
//work with Map
}
Add a header to your request to set content type to application/json
curl -H 'Content-Type: application/json' -s -XPOST http://your.domain.com/ -d YOUR_JSON_BODY
this way spring knows how to parse the content.
In Spring 5
#PostMapping( "some/request/path" )
public void someControllerMethod( #RequestParam MultiValueMap body ) {
// import org.springframework.util.MultiValueMap;
String datax = (String) body .getFirst("datax");
}
#RequestBody MultiValueMap paramMap
in here Remove the #RequestBody Annotaion
#RequestMapping(value = "/signin",method = RequestMethod.POST)
public String createAccount(#RequestBody LogingData user){
logingService.save(user);
return "login";
}
#RequestMapping(value = "/signin",method = RequestMethod.POST)
public String createAccount( LogingData user){
logingService.save(user);
return "login";
}
like that
Simply removing #RequestBody annotation solves the problem (tested on Spring Boot 2):
#RestController
public class MyController {
#PostMapping
public void method(#Valid RequestDto dto) {
// method body ...
}
}
I met the same problem when I want to process my simple HTML form submission (without using thymeleaf or Spring's form tag) in Spring MVC.
The answer of Douglas Ribeiro will work very well. But just in case, for anyone, like me, who really want to use "#RequestBody" in Spring MVC.
Here is the cause of the problem:
Spring need to ① recognize the "Content-Type", and ② convert the
content to the parameter type we declared in the method's signature.
The 'application/x-www-form-urlencoded' is not supported, because, by
default, the Spring cannot find a proper HttpMessageConverter to do
the converting job, which is step ②.
Solution:
We manually add a proper HttpMessageConverter into the Spring's
configuration of our application.
Steps:
Choose the HttpMessageConverter's class we want to use. For
'application/x-www-form-urlencoded', we can choose
"org.springframework.http.converter.FormHttpMessageConverter".
Add the FormHttpMessageConverter object to Spring's configuration,
by calling the "public void
configureMessageConverters(List<HttpMessageConverter<?>>
converters)" method of the "WebMvcConfigurer" implementation class
in our application. Inside the method, we can add any
HttpMessageConverter object as needed, by using "converters.add()".
By the way, the reason why we can access the value by using "#RequestParam" is:
According to Servlet Specification (Section 3.1.1):
The following are the conditions that must be met before post form
data will be populated to the parameter set: The request is an HTTP
or HTTPS request. 2. The HTTP method is POST. 3. The content type is
application/x-www-form-urlencoded. 4. The servlet has made an initial
call of any of the getParameter family of methods on the request
object.
So, the value in request body will be populated to parameters. But in Spring, you can still access RequestBody, even you can use #RequstBody and #RequestParam at the same method's signature.
Like:
#RequestMapping(method = RequestMethod.POST, consumes = {MediaType.APPLICATION_FORM_URLENCODED_VALUE})
public String processForm(#RequestParam Map<String, String> inputValue, #RequestBody MultiValueMap<String, List<String>> formInfo) {
......
......
}
The inputValue and formInfo contains the same data, excpet for the type for "#RequestParam" is Map, while for "#RequestBody" is MultiValueMap.
I wrote about an alternative in this StackOverflow answer.
There I wrote step by step, explaining with code. The short way:
First: write an object
Second: create a converter to mapping the model extending the AbstractHttpMessageConverter
Third: tell to spring use this converter implementing a WebMvcConfigurer.class overriding the configureMessageConverters method
Fourth and final: using this implementation setting in the mapping inside your controller the consumes = MediaType.APPLICATION_FORM_URLENCODED_VALUE and #RequestBody in front of your object.
I'm using spring boot 2.
#PostMapping(path = "/my/endpoint", consumes = { MediaType.APPLICATION_FORM_URLENCODED_VALUE })
public ResponseEntity<Void> handleBrowserSubmissions(MyDTO dto) throws Exception {
...
}
That way works for me
You can try to turn support on in spring's converter
#EnableWebMvc
#Configuration
public class WebConfig implements WebMvcConfigurer {
#Override
public void extendMessageConverters(List<HttpMessageConverter<?>> converters) {
// add converter suport Content-Type: 'application/x-www-form-urlencoded'
converters.stream()
.filter(AllEncompassingFormHttpMessageConverter.class::isInstance)
.map(AllEncompassingFormHttpMessageConverter.class::cast)
.findFirst()
.ifPresent(converter -> converter.addSupportedMediaTypes(MediaType.APPLICATION_FORM_URLENCODED_VALUE));
}
}
Just add an HTTP Header Manager if you are testing using JMeter :

Spring MVC Controller method mapping using form body

I'm building a small application to serve as a client for some third party library here at work. The API states that a Webhookis needed to respond some asynchronous events, but all their methods have the very same signature, apart from a changing _method field between the calls. For example, I have a _method = ping, media, etc.
I'd like to have separate methods on my controller to respond for each one of these methods. If the app allowed me to specify different URLs for each method it would be easy to use Spring MVC's #RequestMapping for each one of them. But I have to specify a single endpoint to receive all calls.
Is there a way (for example using Spring's HttpMessageConverter or something like that) to map different controller methods based on what the Request Body is? I've already tried with #RequestBody, #RequestParam but didn't seem to find anything.
I really, really didn't want to use a bunch of case, switch methods on a front controller to dispatch actions based on my _method field that comes with my POST data, so I happen to believe someone had this problem before and solved it intelligently.
Thanks a lot!
Edit 1: Providing source code
#Controller
#RequestMapping("/webhooks")
public class WebhookController {
#RequestMapping(method = RequestMethod.POST, params = {"_method=ping"})
#ResponseBody
public String ping(){
return "pong";
}
#RequestMapping(method = RequestMethod.POST, params = {"_method=media"})
#ResponseBody
public String media(){
return "media";
}
}
This is the answer:
{
"timestamp": 1440875190389,
"status": 400,
"error": "Bad Request",
"exception": "org.springframework.web.bind.UnsatisfiedServletRequestParameterException",
"message": "Parameter conditions \"_method=ping\" not met for actual request parameters: ",
"path": "/webhooks"
}
Right, I got it working. The answer is a bit tricky so I wanted to register it here should anyone have such problem.
#Neil McGuigan pointed me on the right direction on his comment but I didn't pay attention at first. The main culprit here is a very, very, very bad API design on our remote application's side.
_method is a field used to specify non-standard HTTP verbs such as PUT, PATCH, DELETE, TRACE and so on. This field is filtered by HiddenHttpMethodFilter and the HttpServletRequest is wrapped with this 'new' method. You can see at the file's source how it works.
As I wanted this _method field to get thru the filter without modifying the whole request (and causing the errors because there's no such verb as pingor message on `RequestMethod) I firstly had to deactivate the filter. This could be done by two ways:
I could stop Spring Boot from automagically configuring Spring MVC, skipping WebMvcAutoConfiguration from being loaded when the ApplicationContext was loaded. As you can imagine this is a BIG, BIG, BIIIIG NO because, well, things could happen.
I could use a FilterRegistrationBean to disable the bad filter. Pretty simple and straightforward, this was the method I chose to use:
#Bean
public FilterRegistrationBean registration(HiddenHttpMethodFilter filter) {
FilterRegistrationBean registration = new FilterRegistrationBean(filter);
registration.setEnabled(false);
return registration;
}
Last but not least, I decided to give HiddenHttpMethodFilter a little extension to somehow improve how the requests were getting thru. The Java EE Spec is pretty clear on the Servlet Spec Commandments where it states:
Thou should not alter your request on your side. You must respect the sender (something like that)
Though I agree with this, for the sake of my mental stability I decided to alter it anyway. To achieve this, we can use a simple HttpServletRequestWrapper, override the chosen methods and filter the original request with the wrapped part. I ended up doing something like this:
public class WhatoolsHiddenHttpMethodFilter extends OrderedHiddenHttpMethodFilter {
#Override
protected void doFilterInternal(HttpServletRequest request, HttpServletResponse response, FilterChain filterChain) throws ServletException, IOException {
String paramValue = request.getParameter(OrderedHiddenHttpMethodFilter.DEFAULT_METHOD_PARAM);
if("POST".equals(request.getMethod()) && StringUtils.hasLength(paramValue)) {
String method = paramValue.toUpperCase(Locale.ENGLISH);
List<String> whatoolsMethods = Arrays.asList("ping", "message", "carbon", "media", "media_carbon", "ack");
if(whatoolsMethods.contains(paramValue)){
WhatoolsHiddenHttpMethodFilter.HttpMethodRequestWrapper wrapper = new WhatoolsHiddenHttpMethodFilter
.HttpMethodRequestWrapper(request, "POST", paramValue);
filterChain.doFilter(wrapper, response);
} else {
WhatoolsHiddenHttpMethodFilter.HttpMethodRequestWrapper wrapper = new WhatoolsHiddenHttpMethodFilter
.HttpMethodRequestWrapper(request, method, null);
filterChain.doFilter(wrapper, response);
}
} else {
filterChain.doFilter(request, response);
}
}
private static class HttpMethodRequestWrapper extends HttpServletRequestWrapper {
private final String method;
private final String whatoolsMethod;
public HttpMethodRequestWrapper(HttpServletRequest request, String method, String whatoolsMethod) {
super(request);
this.method = method;
this.whatoolsMethod = whatoolsMethod;
}
#Override
public String getMethod() {
return this.method;
}
#Override
public String getHeader(String name) {
if("x-whatools-method".equals(name)){
return this.whatoolsMethod;
}
return super.getHeader(name);
}
#Override
public Enumeration<String> getHeaderNames() {
List<String> names = Collections.list(super.getHeaderNames());
if(this.whatoolsMethod != null){
names.add("x-whatools-method");
}
return Collections.enumeration(names);
}
}
}
So, what this does is to wrap the request with a new x-whatools-method header when the header is in my whatoolsMethods list. With this, I can easily use #RequestMapping's headers property and map the requests to the correct controller methdods.
Back to the initial question, I'm almost sure (well, 99,95% should be completely sure but let's not risk it) the params property on #RequestMapping works only for request parameters on GET URIs, e.g http://foo.bar/?baz=42. It won't work filtering parameters sent on the request's body.
Thanks Neil for your guidance, even if small! I hope this helps someone.
You can use params in a request mapping:
#RequestMapping(value="/foo", params={"_method=ping"})
Assuming these are post parameters that is
params DOES work for POST, I promise you
Here's my controller:
#Controller
#RequestMapping("/test1")
public class ParamTestController {
#RequestMapping(method = RequestMethod.POST)
#ResponseBody String getA(){
return "A";
}
#RequestMapping(method = RequestMethod.POST, params = {"b"})
#ResponseBody String getB(){
return "B";
}
}
Here's my test:

When use ResponseEntity<T> and #RestController for Spring RESTful applications

I am working with Spring Framework 4.0.7, together with MVC and Rest
I can work in peace with:
#Controller
ResponseEntity<T>
For example:
#Controller
#RequestMapping("/person")
#Profile("responseentity")
public class PersonRestResponseEntityController {
With the method (just to create)
#RequestMapping(value="/", method=RequestMethod.POST)
public ResponseEntity<Void> createPerson(#RequestBody Person person, UriComponentsBuilder ucb){
logger.info("PersonRestResponseEntityController - createPerson");
if(person==null)
logger.error("person is null!!!");
else
logger.info("{}", person.toString());
personMapRepository.savePerson(person);
HttpHeaders headers = new HttpHeaders();
headers.add("1", "uno");
//http://localhost:8080/spring-utility/person/1
headers.setLocation(ucb.path("/person/{id}").buildAndExpand(person.getId()).toUri());
return new ResponseEntity<>(headers, HttpStatus.CREATED);
}
to return something
#RequestMapping(value="/{id}", method=RequestMethod.GET)
public ResponseEntity<Person> getPerson(#PathVariable Integer id){
logger.info("PersonRestResponseEntityController - getPerson - id: {}", id);
Person person = personMapRepository.findPerson(id);
return new ResponseEntity<>(person, HttpStatus.FOUND);
}
Works fine
I can do the same with:
#RestController (I know it is the same than #Controller + #ResponseBody)
#ResponseStatus
For example:
#RestController
#RequestMapping("/person")
#Profile("restcontroller")
public class PersonRestController {
With the method (just to create)
#RequestMapping(value="/", method=RequestMethod.POST)
#ResponseStatus(HttpStatus.CREATED)
public void createPerson(#RequestBody Person person, HttpServletRequest request, HttpServletResponse response){
logger.info("PersonRestController - createPerson");
if(person==null)
logger.error("person is null!!!");
else
logger.info("{}", person.toString());
personMapRepository.savePerson(person);
response.setHeader("1", "uno");
//http://localhost:8080/spring-utility/person/1
response.setHeader("Location", request.getRequestURL().append(person.getId()).toString());
}
to return something
#RequestMapping(value="/{id}", method=RequestMethod.GET)
#ResponseStatus(HttpStatus.FOUND)
public Person getPerson(#PathVariable Integer id){
logger.info("PersonRestController - getPerson - id: {}", id);
Person person = personMapRepository.findPerson(id);
return person;
}
My questions are:
when for a solid reason or specific scenario one option must be used mandatorily over the other
If (1) does not matter, what approach is suggested and why.
ResponseEntity is meant to represent the entire HTTP response. You can control anything that goes into it: status code, headers, and body.
#ResponseBody is a marker for the HTTP response body and #ResponseStatus declares the status code of the HTTP response.
#ResponseStatus isn't very flexible. It marks the entire method so you have to be sure that your handler method will always behave the same way. And you still can't set the headers. You'd need the HttpServletResponse.
Basically, ResponseEntity lets you do more.
To complete the answer from Sotorios Delimanolis.
It's true that ResponseEntity gives you more flexibility but in most cases you won't need it and you'll end up with these ResponseEntity everywhere in your controller thus making it difficult to read and understand.
If you want to handle special cases like errors (Not Found, Conflict, etc.), you can add a HandlerExceptionResolver to your Spring configuration. So in your code, you just throw a specific exception (NotFoundException for instance) and decide what to do in your Handler (setting the HTTP status to 404), making the Controller code more clear.
According to official documentation: Creating REST Controllers with the #RestController annotation
#RestController is a stereotype annotation that combines #ResponseBody
and #Controller. More than that, it gives more meaning to your
Controller and also may carry additional semantics in future releases
of the framework.
It seems that it's best to use #RestController for clarity, but you can also combine it with ResponseEntity for flexibility when needed (According to official tutorial and the code here and my question to confirm that).
For example:
#RestController
public class MyController {
#GetMapping(path = "/test")
#ResponseStatus(HttpStatus.OK)
public User test() {
User user = new User();
user.setName("Name 1");
return user;
}
}
is the same as:
#RestController
public class MyController {
#GetMapping(path = "/test")
public ResponseEntity<User> test() {
User user = new User();
user.setName("Name 1");
HttpHeaders responseHeaders = new HttpHeaders();
// ...
return new ResponseEntity<>(user, responseHeaders, HttpStatus.OK);
}
}
This way, you can define ResponseEntity only when needed.
Update
You can use this:
return ResponseEntity.ok().headers(responseHeaders).body(user);
A proper REST API should have below components in response
Status Code
Response Body
Location to the resource which was altered(for example, if a resource was created, client would be interested to know the url of that location)
The main purpose of ResponseEntity was to provide the option 3, rest options could be achieved without ResponseEntity.
So if you want to provide the location of resource then using ResponseEntity would be better else it can be avoided.
Consider an example where a API is modified to provide all the options mentioned
// Step 1 - Without any options provided
#RequestMapping(value="/{id}", method=RequestMethod.GET)
public #ResponseBody Spittle spittleById(#PathVariable long id) {
return spittleRepository.findOne(id);
}
// Step 2- We need to handle exception scenarios, as step 1 only caters happy path.
#ExceptionHandler(SpittleNotFoundException.class)
#ResponseStatus(HttpStatus.NOT_FOUND)
public Error spittleNotFound(SpittleNotFoundException e) {
long spittleId = e.getSpittleId();
return new Error(4, "Spittle [" + spittleId + "] not found");
}
// Step 3 - Now we will alter the service method, **if you want to provide location**
#RequestMapping(
method=RequestMethod.POST
consumes="application/json")
public ResponseEntity<Spittle> saveSpittle(
#RequestBody Spittle spittle,
UriComponentsBuilder ucb) {
Spittle spittle = spittleRepository.save(spittle);
HttpHeaders headers = new HttpHeaders();
URI locationUri =
ucb.path("/spittles/")
.path(String.valueOf(spittle.getId()))
.build()
.toUri();
headers.setLocation(locationUri);
ResponseEntity<Spittle> responseEntity =
new ResponseEntity<Spittle>(
spittle, headers, HttpStatus.CREATED)
return responseEntity;
}
// Step4 - If you are not interested to provide the url location, you can omit ResponseEntity and go with
#RequestMapping(
method=RequestMethod.POST
consumes="application/json")
#ResponseStatus(HttpStatus.CREATED)
public Spittle saveSpittle(#RequestBody Spittle spittle) {
return spittleRepository.save(spittle);
}

Spring aspects forward and cancel previous request

Here is my question
I want to intercept request before any spring controller call, check and modify request URI. After that it has to call another SPRING controller method.
I used mvc:interceptors however I want to configure it with annotations thats why I need a solution for #Aspect. Everything is working but controller called twice, for the original request and for the new request. Using interceptors I return false and it cancels it, how do I do about Aspect classes? Thank you
Here is my code:
#Component
#Aspect
public class TestAspect {
#Before("execution(* mycontroller.*(..)) &&" + "args(request,response)")
public void interceptUrl(HttpServletRequest request, HttpServletResponse response) {
System.out.println("#Aspect is running!");
System.out.println(request.getRequestURI());
if (request.getAttribute("client") == null) {
request.setAttribute("client", "test");
request.getRequestDispatcher("/newpath/contact").forward(request, response);
}
}
}
You should consider #Around advice instead of #Before. In this case you can simply not execute original request chain.

Why doesn't Spring MVC throw an error when you POST to a controller action that accepts HTTP GET?

I just noticed a weird problem as I've been testing my application. I was accidentally POSTing to a method that accepts HTTP GET (It was a typo - I'm a little tired), but the weird thing is that Spring was executing a GET action anyway - it wasn't throwing an error.
Here is the mapping for my GET action that I was POSTing to instead:
#RequestMapping(value = "/partialMapping/{partialMappingId}/edit", method = RequestMethod.GET)
public ModelAndView edit(#PathVariable long partialMappingId) {
return new ModelAndView(view("edit"), "partialMapping",
partialMappingService.findPartialMapping(partialMappingId));
}
What I would have expected was for Spring to say, "There is no action called /partialMapping/{partialMappingId}/edit for HTTP POST".
Instead... if you use the HandlerAdapter and pass it "POST" and "/partialMapping/1/edit", it runs my index action instead ("/partialMapping"). It doesn't throw an error. Why?
Is this a bug in spring, or is this desired behaviour? It's not a big deal when it comes to production code, but it surely makes debugging problems harder.
Here is the code I am using to execute a controller action in my tests:
protected ModelAndView handle(HttpServletRequest request, HttpServletResponse response) {
try {
final HandlerMapping handlerMapping = applicationContext.getBean(HandlerMapping.class);
final HandlerExecutionChain handler = handlerMapping.getHandler(request);
assertNotNull("No handler found for request, check you request mapping", handler);
final Object controller = handler.getHandler();
// if you want to override any injected attributes do it here
final HandlerInterceptor[] interceptors =
handlerMapping.getHandler(request).getInterceptors();
for (HandlerInterceptor interceptor : interceptors) {
final boolean carryOn = interceptor.preHandle(request, response, controller);
if (!carryOn) {
return null;
}
}
return handlerAdapter.handle(request, response, controller);
} catch(Exception e) {
throw new RuntimeException(e);
}
}
I found this code per another answer to a question on this site.
I believe your test code mimics the dispatch step that tries to find a matching Controller method signature after the URL and HTTP method have resolved. In other words, you are not testing your controller at the right level if you want to test the HTTP message bindings. For that kind of testing you would probably want to deploy to a server (perhaps embedded Jetty inside your test) and use RestTemplate to call it. That's what I do anyway.
If you annotate with Spring MVC annotations as below
#RequestMapping(method = RequestMethod.GET it should work.

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