I want to call an web api method, this is how my web api method looks like:
[HttpPost]
[Route("PostMyService/updatedBy/{updatedByID}/myobjname")]
public void PostTerminalService([FromBody] List<SomeType> lstSomeObj, MyClass myobj, int updatedByID)
{
//Do Something
}
This is how my client looks like:
int loggedinuserid=1;
List<Sometype> liTS = new List<SomeType>();
MyClass myobj=new MyClass();
var url = "api/XYZ/PostMyService/updatedBy/" + loggedinuserid + "/myobjname/" + myobj;
HttpResponseMessage response = client1.PostAsJsonAsync(url, liTS).Result;
But the error/exception I am getting is:
HTTP Error 404.0 - Not Found
Most likely causes:
•The directory or file specified does not exist on the Web server.
•The URL contains a typographical error.
•A custom filter or module, such as URLScan, restricts access to the file.
Any idea how to resolve this? I am kind of hitting a wall on this.
Thanks in advance.
You have "api/XYZ/" prefixed in your client code, but I don't see it on your server code. I predict that you have it in your server configuration but if not you will see issues.
You can only have one object with the [FromBody] tag in WebAPI, it's not clear how your trying to pass the MyClass object.
Only simple objects, ints and strings, can be passed in the uri string so the MyClass object will not be transferred correctly.
I would recommend removing the MyClass object or creating a larger object that encapsulates your List<SomeType> andMyClass` and pass that in the body of the request with the [FromBody] decoration.
Here's more information on the topic
Related
I have started using WebClient(org.springframework.web.reactive.function.client.WebClient) for calling rest services. I have 2 classes say Utility.java and ServiceImpl.java.
ServiceImpl.java is where I use WebClient. A post call I am making looks like -
ClientResponse response = webClient.post()
.uri(path)
.body(Mono.just(inputDTO),InputDTO.class)
.exchange()
.block();
(ClientResponse above is org.springframework.web.reactive.function.client.ClientResponse)
(I am using exchange instaed of retrive because I want headers as well as status code)
Now trying to convert this response into some DTO - ResponseDTO.
Mono<ResponseEntity<ResponseDTO>> mono = response.toEntity(ResponseDTO.class);
ResponseEntity<ResponseDTO> resEntity = mono.block();
ResponseDTO myObj = resEntity.getBody();
So myObj is an object of ResponseDTO class.
The issue is - when I perform the conversion of 'response into ResponseDTO.java' in my utility class, I get myObj = null. But if I do it in my ServiceImpl.java (just after calling post API), it returns the proper body (ResponseDTO object).
The same issue occurs even if I perform the conversion and post call operation in two different methods in the ServiceImpl.java.
Do I need to configure something here?
I figured out what was the issue.
After calling REST api, body in the response if flushed out after I read it from the response for the first time. I had a Sysout statement in service implementation class where I was reading the body content.
Recommendation: Read the body content only once and store it in a variable. Use it wherever required.
I have a controller method like this:
#RequestMapping("/hello")
public String hello(UserForm user) {
return "hello";
}
It receives some request parameters in the UserForm command object. But I have not written any code to add the object to the Model. Still, in the view hello.jsp, I'm able to access the data, like this:
Hello, ${userForm.name}!
Does it mean that Spring MVC adds command objects to the Model automatically?
You don't need #ModelAttribute just to use a Bean as a parameter.
You'll need to use #ModelAttribute or model.addAttribute() to load default data into your model - for example from a database.
Most of the Spring controllers in the real world accept a lot of different types of parameters - Path variables, URL parameters, request headers, request body and sometimes even the entire HTTP Request object. This provides a flexible mechanism to create APIs. Spring is really good at parsing these parameters in to Java types as long as there is an ObjectMapper (like Jackson) configured to take care of the de-serialization.
The RequestMappingHandlerAdapter makes sure the arguments of the method are resolved from the HttpServletRequest.
Spring model data created prior to (or during) the handler method
execution gets copied to the HttpServletRequest before the next view
is rendered.
By now, Spring has processed the HTTP request and it creates the ModelAndView object from the method’s return value. Also, note that you are not required to return a ModelAndView instance from a controller method. You may return a view name, or a ResponseEntity or a POJO that will be converted to a JSON response etc.
ServletInvocableHandlerMethod invocableMethod
= createInvocableHandlerMethod(handlerMethod);
if (this.argumentResolvers != null) {
invocableMethod.setHandlerMethodArgumentResolvers(
this.argumentResolvers);
}
if (this.returnValueHandlers != null) {
invocableMethod.setHandlerMethodReturnValueHandlers(
this.returnValueHandlers);
}
The returnValueHandlers object is a composite of HandlerMethodReturnValueHandler objects. There are also a lot of different value handlers that can process the result of your method to create ModelAndViewobject expected by the adapter.
Then, it has to render the HTML page that the user will see in the browser. It does that based on the model and the selected view encapsulated in the ModelAndView object.
Now, at this stage, the view gets access to the userForm (as in your example above) from the request scope.
I have my API for a small part of my application split over two controllers, because of (external) requirements on the casing of JSON data in the API (some requests should use camelCasing, while others should use PascalCasing).
Now, I have a url that I want to map with PascalCasing for GET, but camelCasing for PUT, so I tried the following:
[PascalCasing] // custom attribute, part of our code
// We configure all controllers that *don't* have this to use
// camelCasing
public class PascalCasedController : ApiController
{
[HttpGet]
[Route("url/to/my/resource/{id}")]
public IHttpActionResult(int id)
{
return Ok(GetResource(id));
}
}
public class CamelCasedController : ApiController
{
[HttpPut]
[Route("url/to/my/resource/{id}")]
public IHttpActionResult(int id, Resource resource)
{
SaveResource(id, resource);
return Ok();
}
}
The GET request works as expected, but if I try to PUT something there with Fiddler, I get the following error message:
Multiple controller types were found that match the URL. This can happen if attribute routes on multiple controllers match the requested URL.
The request has found the following matching controller types:
MyProject.PascalCaseController
MyProject.CamelCaseController
I realize this is probably because WebAPI maps routes to controllers first and actions next, but if HTTP methods are considered, there really isn't any ambiguity here. Is there any way that I can tell WebAPI how to do this, without having to have the methods in the same controller?
#Tomas - There's an interface "System.Web.Http.Dispatcher.IHttpControllerSelector" exposed in System.Web.Http assembly. You can use that interface and create your own HttpControllerSelector. You can then replace the DefaultControllerSelector with your custom controller selector in the HttpConfiguration during AreaRegistration.
httpConfig.Services.Replace(typeof(IHttpControllerSelector), new CustomControllerSelector(services.GetHttpControllerSelector()));
In this custom controller selector you can write your own implementation of SelectController() method of IHttpControllerSelector in which you can call GetControllerMapping() method of IHttpControllerSelector. This will give you the list of all the controllers registered. For every controller you can check for the DeclaredMethods and check for the CustomAttributes for each of the DeclaredMethods. In your case it will be either HttpGetAttribute or HttpPutAttribute.
Check the Method type of the incoming HttpRequestMessage (GET/PUT) and compare it against the value of the CustomAttributes. If you find a match of the combination of incoming request URL and the the respective Http Verb then you take that HttpControllerDiscriptor and return it from the SelectController() method..
This will allow you to have same URL with different methods in two different controllers.
I'm having trouble getting the Web API 2 attribute routing to work.
I've been trying everything I could find this whole evening but I can't find the problem.
What I want to achieve is the following:
Make a POST request to http://localhost:xxxx/api/chat/joingroup/1234 to get to the following API call:
[Route("joingroup/{id}")]
[HttpPost]
public async Task<IHttpActionResult> JoinGroup(string id, string connectionID)
{
await hubContext.Groups.Add(connectionID, id);
return Ok(hubContext.Groups.ToString());
}
This keeps getting me a http 400 message.
{"message":"No HTTP resource was found that matches the request URI 'http://localhost:41021/api/chat/joingroup/123'.",
"messageDetail":"No action was found on the controller 'Chat' that matches the request."}
But sending a post to: http://localhost:41021/api/chat/sendmessage/pm/123123 and also to http://localhost:41021/api/chat/joingroup gives me a 200
The chatcontroller:
[RoutePrefix("api/chat")]
public class ChatController : ApiController
{
IHubContext hubContext = GlobalHost.ConnectionManager.GetHubContext<ChatHub>();
[...]
[Route("joingroup/{id}")]
[HttpPost]
public async Task<IHttpActionResult> JoinGroup(string id, string connectionID)
{
await hubContext.Groups.Add(connectionID, id);
return Ok(hubContext.Groups.ToString());
}
HTTP POSTS to http://localhost:xxxx/api/chat/sendmessage are working fine.
I cannot figure out why it isn't going to the correct method when I'm calling a POST on http://localhost:xxxx/api/chat/joingroup/1234.
SOLUTION:
The solution was to reference both values that are needed in the JoinGroup method, id and connectionID. Now the request will hit this method.
Using:
http://localhost:xxxx/api/chat/joingroup/john?connectionid=123 will work.
I noticed two things on the code you sent through:
the path you POST to is: localhost:xxxx/joingroup/1234 , this
should be localhost:xxxx/api/chat/joingroup/1234
because you have 2 parameters for the joingroup, you will need to pass both of them through, may be like this localhost:xxxx/api/chat/joingroup/1234?connectionID=value or you can pass it on the request body
if the connectionID is optional you can modify the method to use option al parameters like this
public string JoinGroup(string id, string connectionID = "")
please let me know if this helps.
Thanks
Ashraf
I assume the connectionID parameter references the POSTed data. The easiest thing to make it work is to decorate it with the [FromBody] attribute and put an = in front of the value being sent like this: =MyConnection1.
Web API expects an object with properties or an array otherwise. Alternatively, you can wrap the connection ID with a custom class and pass it serialized as JSON/XML.
Web API allows me to capture the body of a POST request in a JObject:
$.post('/api/Query/DoSomething', { Foo: "one", Bar: 4 });
public string Post(JObject data)
{
// data is populated
}
However the same technique does not work with a get request and URI parameters.
$.get('/api/Controller', { Foo : "one", Bar : 4 });
public string Get([FromUri]JObject data)
{
// data is empty
}
Any workaround here?
It doesn't work because a GET request does not have a body, and hence no content type. Therefore, Web API does not know that you have JSON in your URL. You have a few choices:
Pass your data as query string parameters, as is traditionally done in GET requests, and change your method to accept those parameters individually, or in a regular class (POCO).
Change your GET method to accept a string instead of a JObject, then use JSON.Net to deserialize it manually, e.g. JObject obj = JObject.Parse(data);
If you're feeling ambitious, you might be able to implement a custom binder to do this.
My recommendation is option 1. Traditionally, a GET method is just intended to look something up, so you really should only be passing IDs and simple query options anyway. It is unusual to be passing JSON data in a URL. Also the length of URLs can be limited by some browsers. If you find you are needing to pass JSON data, use POST (or PUT) instead.
You can create an object and bind to it using the FromUri.
Check out this solution which I am using https://stackoverflow.com/a/49632564/2463156.