I have seen a lot of code that uses this getForObject() method that takes a URI and replaces things in {} with the numbers at the end of the method.
My question is: what exactly IS http://localhost:8080/spring-rest/foos? Is it a file of some sort? What would it look like in this context.
In your example:
Foo foo = restTemplate.getForObject(URI, Foo.class, "1");
is actually trying to GET a REST resource with an HTTP request.
Under the covers:
The URL template is rendered to http://localhost:8080/sping-rest/foos/1
The HTTP client issues a GET request to http://localhost:8080/sping-rest/foos/1
The REST service can respond with a JSON representation of that resource, such as {"id":1,"content":"Hello, World!"}
The HTTP client converts that JSON response into an instance of Foo.class (using message converters)
You get an instance of Foo!
The spring.io website lists a lot of guides, you should definitely check them out! There's even a "Consuming a RESTful web service" guide.
Related
I'm developing microservise which receives HTTP POST requests and then redirects them to another destination point in order to receive response, handle it and hand it to another system.
My question is - how can I avoid deserealization while receiving these requests? The microservice don't handle incoming JSONs. From the performance point of view, it's better to avoid deserealization.
I heard I can use Nginx or Apache but how can I embed them into the microservice?
Is there any proven solution? Just don't want to invent a bicycle.
I don't know what is the technology stack you are using (programming language, framework.. etc) but I suppose that in all of them is a way to recieve incoming rest requests without need to deserialize the body.
For example in a java/spring scenario you can define in the corresponding controller method the body parameter as string and in this case there isn't any deserialization of the body, the method will recieve it as a plain string so you can forward it as is to the other service:
#PostMapping(value = "/path")
public ResponseEntity controllerMethod(#RequestBody String body) {
// your code here
}
I am trying to consume this, by following the tutorial from http://spring.io/guides/gs/consuming-rest/.
And I am interested in the "feeds" part of the response only.
My question is:
Is there any other way without using the toString() method in the tutorial. As, I want to access the some parts of response body and display it on a webpage.
Please, provide me with the details of the model and controller.
I have a rest api set up at api/books, and one can send a new book object there, and it will be added to the database. The guestion is, how can I correctly catch what is being POST'ed, so one can for example, validate what is being sent?
#RequestMapping(value="/api/books", method = RequestMethod.POST)
public String bookSavePost(#RequestBody Book book) {
bookRepository.save(book);
return "redirect:/api/books";
}
This works, as in it saves the book and I can catch what the user sends, but with this enabled, it overrides the default REST method, which doesn't allow one to actually view the api anymore. If I change this particular method to GET, it returns a string "redirect:/api/books", so it doesn't even redirect anything. Is there some way to actually redirect it to the rest api endpoint?
You can write your own reuquest Interceptor .
Spring provides HandlerInterceptor class :
https://docs.spring.io/spring-framework/docs/current/javadoc-api/org/springframework/web/servlet/HandlerInterceptor.html
Here is a quick sample how to do this:
https://www.baeldung.com/spring-mvc-handlerinterceptor
A redirect requires three two things to be successful: A HTTP code of 301 or 302 AND a location header that includes the endpoint to which you want the client to visit.
E.g., in the headers section you should have
location: '/correct/endpoint'
Some GCP API methods require an empty request body, others require {} in the body. I can't figure out any pattern.
Examples of methods that require an empty request body, and return an error if called with {}:
https://cloud.google.com/pubsub/docs/reference/rest/v1/projects.topics/getIamPolicy
https://cloud.google.com/iam/reference/rest/v1/roles/list
Examples of methods that require {} in the body, and return an error if called with an empty body:
https://cloud.google.com/resource-manager/reference/rest/v1beta1/projects/getIamPolicy
https://cloud.google.com/pubsub/docs/reference/rest/v1/projects.topics/create
Confusingly, all four of these docs say that the request body must be empty! For the second group, I'd say that's a bug: the body must be non-empty; it must be {}.
This is pretty annoying - it feels like random difference peppered across the methods? Is there any rhyme or reason here? Couldn't the body {} methods accept an empty body?
Some ideas that don't seem to explain the difference:
Since many products use IAM, those functions could have quirky behavior. But see above - getIamPolicy is different between products.
Different product teams could decide on different local conventions. But see above - the pubsub API has calls in each camp.
The first two links that you shared are HTTP GET methods, which should not have a body, as it should only retrieve data, and all the information can be passed through the URL and some query parameters.
The other two links are HTTP PUT methods, which expect a payload to update the current content of a given entity.
You can find more explanation about how the HTTP methods are defined in the IETF RFC 2616, explaining the HTTP protocol.
When I use HTTPService.send(paramter) as a POST request, the web server does not appear to see variable "parameter" if it is a string. The server sees the parameter if it's an Object, but I'm looking to use something like httpservice.send(JSON.encode(object)); Is this possible?
Why not use the actual request objects.
in your service define request objects and post them or send them as get if you please.
Sample code here: http://pastebin.com/ft7QW2vg
Then just call .send on the service.
on the server you can simlpy process if with request.form (Asp)
Failing which why not append it to the url with a binding expression. (you would need to encode it since you would be more or less faking a url or a get behaviour).