I have a Web API controller that looks like this:
[HttpPost]
public IHttpActionResult Test()
{
return Ok();
}
This is correct syntax, However when I try to call this from a service in Angular 2, I get the error message: "json parsing error syntax error unexpected end of input." To resolve this issue, I have to put a value into the ActionResult such as
return Ok(1)
Am I missing some configuration? My Angular 2 service call looks like this:
return this.http.post(API/Controller/Test).map(res => res.json());
Another way:
All my http.get, post or put call (for uniformity):
.map(this.extractData)
In extractData (UPDATED: thanks to raykrow feedback, short code):
private extractData(res: Response) {
return res.text() ? res.json() : {}; ;
}
I guess that when you receive an empty response (without payload) you don't need to call the json method. Under the hood, the XHR response is undefined, JSON.parse(undefined) is called and an error is thrown.
You could skip the call of the map operator:
return this.http.post(API/Controller/Test)/*.map(res => res.json())*/;
Strictly speaking if your API is returning an OK code with no content you should return 204 (no content) - Angular would also be happy with this and not try to parse anything. So your controller method would become:
[HttpPost]
public IHttpActionResult Test()
{
return NoContent();
}
Related
Could you please give me an advice, what is the proper way to return HttpStatus.BAD_REQUEST from webflux handler?
Here's the code, it seems to work properly, exception message returns as needed, but the response status is 200, while needed to be 400. Please note, that returning media type is TEXT_EVENT_STREAM -
#Component
public class ResolveHandler {
public Mono<ServerResponse> resolve(ServerRequest request) {
return ServerResponse.ok().contentType(MediaType.TEXT_EVENT_STREAM)
.body(
new ResultsFluxer(
Integer.valueOf(request.queryParam("numberOfIterations").orElse("0")),
request.queryParam("function1").orElse(""),
request.queryParam("function2").orElse(""),
orderingType
)
.getResult()
.onErrorResume(e -> Flux.just(e.getMessage()))
, Flux.class);
}
}
I have this back-end system that produces json. Is it possible to pass that data through a controller on request and correctly setting the mimetype? Everything I've tried so far tries to re-serialize the data and thus escaping json string.
I've tried adding [Produces("application/json")] to the controller. Setting the response type: Response.ContentType = MediaTypeNames.Application.Json;, returning a JsonResult object: return new JsonResult(jsonString);
The back-end doesn't have a JsonSerializer I can add to the JsonSerializerOptions and I only need it for this specific controller.
In short: If I just return the json string as an IActionResult without doing anything the controller works except for the fact that the content-type isn't set to application/json. Is there any way to do this without affecting anything else?
I feel like this shouldn't be such a exceptional use case but I just can't seem to find the answer.
I had the same need. I solved it by having my action method return an ActionResult like so:
public ActionResult SomeActionMethod(){
string json = GetJsonFromBackenend();
return new ContentResult {
Content = json,
ContentType = "application/json; charset=utf-8",
StatusCode = StatusCodes.Status200OK
};
}
You could declare the return type as an IActionResult if you prefer as #Jurgy mentioned.
I'm beggining to play with Angular2. I have developed a basic RESTful API using Jersey. I tested it and it works fine (with browser and SOAP UI). This is the code:
#GET
#Produces(MediaType.APPLICATION_JSON)
public TwoWordsMessage getMessage() {
TwoWordsMessage message = new TwoWordsMessage();
message.setFirstWord("hello");
message.setSecondWord("world");
return message;
}
I'm tryng to call the service from an Angular2 app:
this.http.request(this.url).subscribe((res: Response) => {
this.message = res.json();
});
I can see (debbuging) that "getMessage" method is called and it returns the TwoWordsMessage object but the Angular2 application never gets it. The same code with the url http://jsonplaceholder.typicode.com/posts/1 works fine.
What I'm doing wrong?
Thanks!
Are you calling the http request inside a component or a service? Does a function or method fire off the http request?
Also, can you see if there are errors coming back from the response? The subscribe method can take three functions as parameters, first one being on success, second on error, third on completion. If there's an error in the AJAX call (400s, 500s, etc), your code would never be able to handle it. Try this:
this.http.request(this.url).subscribe((res: Response) => {
this.message = res.json();
}, (error) => {
console.warn(error)
});
and see what is spit out. To further debug, you can even use the .do() method on the Observable:
this.http.request(this.url)
.do((res: Response) => console.log(res)) // or other stuff
.subscribe((res: Response) => {
this.message = res.json();
});
The .do() method will execute an arbitrary function with the response without actually affecting it.
If not, you could also try changing the http call to http.get(). I don't think that's the problem, but the Angular docs do not state what method is defaulted to with http.request() (although I would be almost certain it's a GET).
I finally got it working. It's a CORS problem.
The console showed the error:
"No 'Access-Control-Allow-Origin' header is present on the requested
resource"
I changed the resource method like this:
#GET
#Produces(MediaType.APPLICATION_JSON)
public Response getMessage() {
TwoWordsMessage message = new TwoWordsMessage();
message.setFirstWord("hello");
message.setSecondWord("world");
return Response.status(200).header("Access-Control-Allow-Origin", "*").entity(message).build();
}
You can find useful information here:
http://www.codingpedia.org/ama/how-to-add-cors-support-on-the-server-side-in-java-with-jersey/
I'm working on a node.js server using express and a android native app, using Retrofit 1.9.
For a login API that returns only a true/false answer to the client, should JSON still be used?
As I see it, the server has only to send a status code response:
if(isLegal) {
res.sendStatus(200);
dbConnector.updateUser(token);
}
else{
console.log('Token is not legal');
res.sendStatus(403);
}
But the Retrofit framework tries to convert the response to JSON, which makes me think I must send a JSON object with the answer, though it seems weird.
My retrofit restClient:
public class RestClient {
private static final String URL = SessionDetails.getInstance().serverAddress;
private retrofit.RestAdapter restAdapter;
private ServerAPI serverAPI;
public RestClient() {
restAdapter = new retrofit.RestAdapter.Builder()
.setEndpoint(URL)
.setLogLevel(retrofit.RestAdapter.LogLevel.FULL)
.build();
serverAPI = restAdapter.create(ServerAPI.class);
}
public ServerAPI getService() {
return serverAPI;
}
}
And usage:
restClient.getService().login(token.getToken(), token.getUserId(), new Callback<Void>() {
#Override
public void success(Void aVoid, Response response) {
Log.d("Chooser", "Successful login on server.");
}
#Override
public void failure(RetrofitError error) {
error.printStackTrace();
Log.d("Chooser", "Login failed on server.");
}
});
Using it as it is results with the following error:
com.google.gson.JsonSyntaxException: java.lang.IllegalStateException: Expected BEGIN_OBJECT but was STRING
There are many topics on this issue but no certain answer about the correct (or better) method to use.
Any ideas about the best implementation in these cases?
Sending an empty body with your HTTP response is perfectly legal and some clients may care only about the response status but some clients may expect to get a response so sending a body never hurts and sometimes may be useful.
You can include a JSON response in addition to the HTTP response status:
// Express 4.x:
res.status(403).json({error: 'Token is not legal'});
// Express 3.x:
res.json(403, {error: 'Token is not legal'});
Such an error message can be very useful for the client development. You can get 403 for many reasons, illegal token, expired token, a legal not expired token but for the wrong user that doesn't have some privilege - adding a specific error message in addition to the HTTP response code can tell the client what exactly went wrong and allows the client-side code to show a better error message to the user.
Also, note that true and false are also valid JSON.
I want to build a library that will save the Json content of request and response on annotated Spring controller.
So i've build my own annotation #Foo and put it on some controllers:
#Foo
#RequestMapping(method = RequestMethod.POST, value = "/doSomeThing", produces = {
MediaType.APPLICATION_JSON_VALUE, MediaType.TEXT_XML_VALUE,
MediaType.APPLICATION_XML_VALUE})
public ResponseEntity<T> doSomething(/*some parameters*/) {
T t = doSomeJob(T.class);
return new ResponseEntity<T>(t, HttpStatus.OK);
}
I have no guarantee that request and response are in Contrellor's parameters!
And i'm catching the call on any Controller having that annotation within an #AfterReturning AOP pointcut.
#Component
#Aspect
public class XYInterceptor
#AfterReturning(
pointcut = "execution(#my.annotation.Foo)")
public void doSomethingWithJsonContent(JoinPoint joinPoint) throws Throwable {
//How can i get json value of request and response here?
}
How can I get request and response content formatted in json (such as it is send/returned to the client) ?
Thanx for your help!
Well, you need request and response somehow accessible from your controller method, either via an injected class member, method parameter or method return value. It has got to be somewhere. Because you did not explain where you intend to get it from, I can just post a general answer showing how to determine method arguments and return value from an #AfterReturning advice. If you update the question with more detailed information, I can also update the answer accordingly.
My pointcut (the commented-out one also works, choose your favourite one) binds the return value to a parameter and just assumes that both request and response are of String type. Feel free to replace by your favourite. Furthermore, you can bind a parameter from your intercepted method (no matter where it is in the signature) to a typed advice method parameter if you know that the parameter exists and also know its (super) type. This way you can get rid of the slow and ugly loop over getArgs().
//#AfterReturning(pointcut = "execution(#my.annotation.Foo * *(..))", returning = "response")
#AfterReturning(pointcut = "#annotation(my.annotation.Foo)", returning = "response")
public void interceptRequest(String response, JoinPoint thisJoinPoint) {
System.out.println(thisJoinPoint);
for (Object arg : thisJoinPoint.getArgs()) {
if (arg instanceof String)
System.out.println(" request = " + arg);
}
System.out.println(" response = " + response);
}