I am using Jersey and converting my existing data services into RESTful data services. Most simple GETs and PUTs I could successfully convert. But following are some I am not able to convert:
X Get (T) // for complex queries with complex result
X Post (T) // for creating with complex result
X PUT (T) // for updating with some success message object
where T and X are a complex objects
I have tried #queryparam, #pathparam with complex objects on GET with #consume & #produce and those didn't work. Also tried POST (though I really needed GET) with url encoded and that didn't work too.
Please Help. I am in need of sample code that does it.
REST isn't designed to handle complex queries as the query is actually the URL. When you retrieve a resource you specify the ID of the resource you want. This is simply a number or string and is easily represented in the URL for example;
http://host/employee/57
would get you employee 57. If your requirements are more complicated then you might want to use a search method, where you pass several parameters. You could use #QueryParam here but this isn't really REST in a pure form.
If you are POSTing or PUTting data then you use the same URL as you would if you were doing a GET, only this time you send data in the content body. As you are able to serialize the object in order to return it to a GET request your client should also be able to serialize it to send it to you in a PUT or POST.
Here's an example of a GET and POST;
#XmlType
public class Employee {
private int id;
private String name;
//getters and setters
}
#Path("/employee")
public class EmployeeService {
#GET
#Path("/{id}")
#Produces(MediaType.APPLICATION_XML)
public Employee get(#PathParam("id") String id) {
Employee e = employeeDao.getEmployee(id);
if (e != null) {
return e;
} else {
throw new WebApplicationException(404);
}
}
#POST
#Consumes(MediaType.APPLICATION_XML)
#Produces(MediaType.APPLICATION_XML)
public Employee post(Employee employee) {
return employeeDao.insertEmployee(employee); //Assumes your DAO sets the ID
}
}
Related
If I have a Get request that returns orders of clients, how can I filter the response to give me the objects that have a specific value for example that are made by those specific clients in Spring Boot?
I have tried with #PathVariable and #RequestParams but every attempt failed.
Thank you in advance.
If you want to show a specific order which has an identifier of some sort, use #PathVariable. In the following example, the identifier is a String, but in many case it will rather be long or an Integer.
#RestController
#RequestMapping("/orders")
public class OrdersController {
#GetMapping("/{id}")
public Order getOrder(#PathVariable("id") String id) {
// get the order with a specified id from the backend
}
}
The web request in this case will look like http:/<host>:<port>/orders/123
If you want to filter the order by some name, like 'madeBy John', use Request parameter:
#RestController
#RequestMapping("/orders")
public class OrdersController {
#GetMapping("/")
public List<Order> getOrdersFilteredByName(#RequestParam("madeBy") madeBy) {
// get the order filtered by the person who made the order
// note, this one returns the list
}
}
In this case the web request will look like this: http:/<host>:<port>/orders?madeBy=John
Note that technically you can implement whatever you want at the backend, so you can pass, say, John in the first example as a path variable, on server its a String after all, however what I've described is a straightforward and kind-of-standard way of doing these things - so can expect to see this convention in many projects at least.
#RestController
#RequestMapping("/order")
public class OrderController {
// http://<host>:<port>/order/1
#GetMapping("/{id}")
public Order getOrder(#PathVariable Long id) {
// Return your order
}
// http://<host>:<port>/order?madeBy=John
#GetMapping("/)
public List<Order> getOrdersMadeBy(#RequestParam("madeBy") String madeBy) {
// Return your order list
}
}
I have a service method which looks like this
public void deleteData(Data data) {
this.dataDao.deleteData(data);
}
Data class have several fields in it. Somethig like this
private String name;
private String category;
private String discriminator;
private String description;
private String appName;
// getters & setters
I need to write a rest method for this. I was thinking to write something like this
#DELETE
#Path("/deleteData")
public Response deleteData(Data data) {
// implementation
}
The problem is that using #DELETE with entity body is not recommended or widely used.
My question is if it's ok to use #PUT instead of #DELETE? I can't change the service method implementation so that's not an option. What's the next best alternative here?
UPDATE
In dataDao.deleteData() method, finding an object is not done by object's ID. It looks something like this:
DataEntity entity = this.findDataByNameAndAppName(data.getName(), data.getAppName());
I decided to do something like this:
#DELETE
#Path("/deleteDataset")
public Response deleteDataset(#QueryParam("name") String name,
#QueryParam("appName") String appName) {
// implementation...
}
I didn't find any example of #DELETE method with #QueryParam, though. All examples was using #PathParam instead.
Well, DELETE is meant for... deleting stuff. So stick to that (without body).
You could either delete a resource using its unique identifier sent as a path parameter:
DELETE /resources/{id} HTTP/1.1
Host: example.org
If you need to delete multiple resources, you could consider query parameters to filter a collection of resources and then delete the resources that match such criteria:
DELETE /resources?name=foo&category=bar HTTP/1.1
Host: example.org
For example I have a bean
public class Order
{
int orderID;
String name;
}
And I have a POST operation
#ApiOperation(value = "Insert a new order", response = Order.class)
#RequestMapping(value = "/addOrder", method = RequestMethod.POST)
#ResponseStatus(HttpStatus.CREATED)
#ResponseBody
public Order addOrder(#Valid #RequestBody Order order)
{
//Set random id here
order.id = 'xxxxx';
Order o = orderService.insertOrder(order);
return o;
}
And in Swagger I have the following:
So my question is, how do I hide id on POST but show ID on GET?
Or should I add a description saying that even if you choose to add an ID it wont do anything and just return my random id? Just like in Kubernetes (uid)
And properties like read-only in #ApiModelProperty will solve anything?
A simple approach is to split your bean in two - one for creating a new object, and another one which extends that for data about an existing object.
e.g.
public class IncompleteOrder {
String name;
}
public class ExistingOrder extends IncompleteOrder {
int id;
}
Then have your POST method take an object of IncompleteOrder and return one of ExistingOrder. I'd also delegrate responsibility for assigning a random order id to the underlying service...
public ExistingOrder addOrder(#Valid #RequestBody IncompleteOrder order) {
ExistingOrder o = orderService.insertOrder(order);
return o;
}
The same thing could be achieved by having two completely separate classes with no inheritance relationship, which would probably be appropriate if there was a significant divergence between the information needed to create a new order from the information which is on an existing order.
An alternative is to ask what the id is actually for - why are your clients getting integer id's for anything? Ideally, if they want any information about the order they should be querying the API for the resource, and to do that they need the URI of the order rather than the integer id. So external services communicating about an order should be passing the URIs back and forth rather than ids. Perhaps you could encourage your clients to communicate with each via the URI you return in the Location header from your POST request? Then you could do away with exposing the id on your response and have a purely symmetric request / response body.
I have a simple REST client with GET POST and DELETE methods.
Weird things is that only GET methods work, neither POST nor DELETE doesn't even get hit and response is "404 Not Found" of course.
Here's my REST service and the client:
Interface:
public interface MyInterface {
#GET
#Path("/content")
#Produces(MediaType.APPLICATION_JSON)
Response getAirports();
#DELETE
#Path("/content/{id}")
#Produces(MediaType.APPLICATION_JSON)
Response deleteAirport(#PathParam("id") String id);
}
Implementation:
#Path("/source")
public class SourceService extends AbstractService implements MyInterface {
#Override
public Response getContent() {
DBCollection collection = getDBCollection("content");
DBCursor cursor = collection.find();
String serialize = JSON.serialize(cursor);
return Response.status(Response.Status.OK).entity(serialize).build();
}
#Override
public Response deleteContent(#PathParam("id") Integer id) {
DBCollection collection = getDBCollection("content");
BasicDBObject query = new BasicDBObject();
query.append("id", id);
collection.remove(query);
return Response.status(Response.Status.OK).build();
}
}
Client:
// This is working
public void getContent() {
WebTarget path = collect.path("/content");
Response response = path.request().get();
LOGGER.info("collect.ping: " + response.readEntity(String.class) + "\n");
}
// This is not working
public void deleteContent(Integer id) {
WebTarget path = collect.path("/content/"+id);
Response response = path.request(MediaType.APPLICATION_JSON).delete();
System.out.println("object deleted:"+response);
}
I've tried requesting with jersey or apache clients but all of them return 404 and I'm like hopeless now.
Hope you can give me a direction.
This looks like a possible duplicate of Inheritance with JAX-RS. Have you tried replicating all annotations in the subclass or none, means do not use #PathParam in the implementation class at all?
If you actually can debug your client and you are indeed able to "Step through" the client code?
If you place a break-point within your server code and you never actually "break" on it? Then the problem is with the way you are exposing your web service and how you are then trying to consume it.
Try to change the parameter type expected by the Server and the type you pass from your client.
If you can change it on the server and client to a simpler type.. i.e.. an integer.. and then you can actually capture a breakpoint in both client and server, then you know that the problem is in your types.
I hope you can understand what I'm saying? You really need to simplify your parameters and/or try it without parameters first.
When you get something simpler working, then you can extend it to something else.
try just changing it to a string... such as "airport" Also, you are passing a parameter in the client as this:
public void deleteAirport(String iata) {
But you don't use "iata" in your client code...
So I am new with restlet. I am creating a Android application that can communicate with a GAE server (with objectify DB)
I Did this very good tutorial to learn:
http://www.tutos-android.com/webservice-rest-android-appengine-restlet-objectify
It's working very well but do very little.
Onely 2 methods:
public interface UserControllerInterface {
#Put
void create(User user);
#Get
Container getAllUsers();
}
For my application its more complicated so I add many more methods:
public interface UserControllerInterface {
#Put
public void createUser(ObagooUser user);
#Put
public void createMessage(ObagooUser user, String message);
#Put
public void updateMessage(ObagooMessage message);
#Get
public List<ObagooUser> getAllUser();
#Get
public ObagooUser getUserById(String id);
#Get
public List<ObagooMessage> getAllMessage();
#Get
public List<ObagooMessage> getAllMessageFromSender(ObagooUser sender);
#Get
public ObagooMessage getFreeMessage(ObagooUser user);
}
Each of these mothds working server side (I tested with Junit).
Now I am coding the android part and I am having problems.
When I do a simple call to getAllMessage() I get an error:
java.lang.IllegalArgumentException: id cannot be zero
at com.google.appengine.api.datastore.KeyFactory.createKey(KeyFactory.java:44)
at com.googlecode.objectify.ObjectifyFactory.typedKeyToRawKey(ObjectifyFactory.java:269)
at com.googlecode.objectify.impl.ObjectifyImpl.find(ObjectifyImpl.java:159)
at com.googlecode.objectify.impl.ObjectifyImpl.find(ObjectifyImpl.java:183)
at com.obagoo.dao.ObagooUserDAO.getUserById(ObagooUserDAO.java:43)
at com.obagoo.controller.ObagooController.getUserById(ObagooController.java:47)
It's going in the wrong method (getUserById).
I put a break point in my getAllMessage and it's going in, but it is also going in other methods.
If I test many times, sometimes it's calling, createUser or another random method.
Do you see what I am doind wrong?
Adding the getAllMessage code:
public List<ObagooMessage> getAllMessage() {
// logger.debug("Getting all Obagoo Messages");
List<ObagooMessage> msg = new ArrayList<ObagooMessage>();
Objectify ofy = ObjectifyService.begin();
Query<ObagooMessage> q = ofy.query(ObagooMessage.class);
for (ObagooMessage u : q) {
msg.add(u);
}
return msg;
}
In the examples that I've seen, its always shown that you should separate the controller/resource handling the URI for the list resource from the single item (id/name based) resource. So you would have something like:
router.attach("/users", UsersController.class);
router.attach("/users/{id}", UserController.class
router.attach("/messages", MessagesController.class);
Notice the plural naming on the first class: UsersController, and singular naming on the the second class: UserController. The first class would handle cases where no id was being provided, such as a get of all users. Also, note when the id is provided in the URI, it can be automatically mapped into an id field on the class. So the Get method has no parameters on the method call.
As for handling a subset, then for messages from a specific user, that could be handled with query parameters. For instance when calling via a URI with /messages?sender=id, the MessagesController.class would use the following in the method handling the Get:
Form queryParams = getRequest().getResourceRef().getQueryAsForm();
String id = queryParams.getFirstValue("sender");
Hope that helps. I'm no expert, so anyone feel free to correct me.
As error says: you are creating a key with zero Id.
My gues is that your ObagoMessage Id field is long? You should make it Long. Primitive long Id values are not autogenerated, while object type Long are. See the docs.