I am just trying out the first example of GAE Endpoints, I modified the sample API Method to resemble this.
#ApiMethod(name = "sayHi")
public MyBean sayHi(#Named("name") String[] names) {
My expectation is to receive a array of strings.
Now when I use the Google API Explorer to test this, [https://apis-explorer.appspot.com/apis-explorer/]
it generates API like this
POST https://myprojectid.appspot.com/_ah/api/myApi/v1/sayHi/arg1/arg2/arg3?fields=data
It eventually returns 404 error. Since the endpoint is not recognized.
What am I doing wrong here? In fact explorer shows name as String not String[]. Any help is appreciated!
First things first: does this work when there is a single String parameter? There's some servlet mapping magic that needs to happen to expose endpoints, and if that is not present in the project, things won't work. See this link to make sure your web.xml is as it should be.
Looking at this link, it seems that if your method parameter is a basic type (not a real Java object), and if it is not specifically included in a #Path annotation, there's some uncertainty in what will happen in your Api:
Path parameters are the method parameters included in the path property of the #ApiMethod annotation. If path is unspecified, any parameters not annotated with #Nullable or #DefaultValue will be automatically added to the path (they will be path parameters).
So it seems that by not including "name" in a #Path annotation, the docs don't state what the format of the path will be. The generated descriptor that the Explorer is looking at seems to think the right answer is /names[0]/names[1]/names[2], kind of like C-style varargs. It might be this disconnect that causes your 404 to happen. Can you try by including "name" in a #Path annotation?
Instead of having an array as a parameter of the endpoint method, you should put an object (java bean) which contains an array as a property.
Then you get the object in your method and you just read the property and treat it as an array.
Edit after some more research, following your comment
Indeed when you try to pass an array as a Path parameter it doesn't work. The different elements of your array are added to the URL (as you show in your question) and it generates a 404 Not Found error. The trick is that you should pass this array as a Query parameter and not a Path Parameter. See this doc: https://cloud.google.com/appengine/docs/java/endpoints/parameter-and-return-types#path_parameters
And indeed, if you do something like that it works very well:
#ApiMethod(name = "sayHi",
path = "sayHiWithName")
public MyBean sayHi(#Named("name") String[] names) {
MyBean response = new MyBean();
response.setData("Hi, " + names[0] + names[1]);
return response;
}
Note that the parameter is NOT added to the path (i.e. we don't have a path like sayHiWithName/{name}).
Related
we have an application running Jersey 2.25 and we have an old interface that contains a signature like this:
#GET
#Path("/release/{id}.{filename}")
public Response release(#PathParam("id") long id, #PathParam("filename") String filename) { ... }
This interface worked fine under Jersey 1, but now we are having problems. After a little research we found that when Jersey 2 attempts to inject the value into the path parameter of the id value, it takes both parameters which of course causes a NumberFormatException as it cannot parse a parameter 1031.myfile.txt as a long. Where as it should have split the value into two parameters.
As stated with Jersey 1 this functioned perfectly, but since we moved to Jersey 2 we've noticed the problem during testing. Is this a change in behavior of Jersey, meaning we'll need to redefine our interface, or is this something that was simply overlooked during the development of Jersey 2?
To resolve this issue, you'll need to redefine your interface to handle this change in behavior. You can either modify the path parameter to accept a string that contains both the "id" and "filename" values and then parse the string within the method to extract the separate values, or you can modify the path parameter to accept two separate values, one for the "id" and one for the "filename".
In the first solution, you can modify the path parameter to the following:
#GET
#Path("/release/{id_filename}")
public Response release(#PathParam("id_filename") String id_filename) {
String[] parts = id_filename.split("\.");
long id = Long.parseLong(parts[0]);
String filename = parts[1];
// rest of the implementation
}
In the second solution, you can modify the path parameter to the following:
#GET
#Path("/release/{id}/{filename}")
public Response release(#PathParam("id") long id, #PathParam("filename") String filename) {
// rest of the implementation
}
I'm developing API using Spring Framework and faced a problem that can be solved by simply adding a necessary logic to every place I have it, but I think that there might be an elegant solution to fix it.
I have the following method in my controller:
#GetMapping("/user/{userId}/permissions")
public List<PermissionDto> list(#PathVariable long userId,
#ModelAttribute #Valid PermissionCriteria criteria) {
return permissionService.list(criteria);
}
The thing is that in dto I have a field called userId. It's made not to have a lot of arguments going to the method of the service. But, I want this user id to be set exactly from path since I use the URL that specifies that we are adding permission exactly to specific user resource. It's doable by making addition line that uses setter in the criteria and sets the value of userId. However, now I should never forget to add this line every time I have a case like that. That's why I decided to move it to InitBinder:
#InitBinder(PERMISSIONS_CRITERIA_NAME)
public void permissionsCriteriaInitBinder(WebDataBinder binder) {
PermissionsCriteria criteria = (PermissionsCriteria) binder.getTarget();
Optional.ofNullable(requestHelper.getUserId())
.map(Long::parseLong)
.ifPresent(criteria::setUserId);
}
It works fine. The user ID is set from the path. However, If I specify request parameter and path variable at the same time, even though userId is set from the path in init binder, it's overridden afterwards before it goes to the controller method. So, this one doesn't solve all the issues.
What I want to find, is someplace where the logic can be put to apply to both init binder(I need it for validation) and controller method. Maybe there is a special type of hook or interceptor or at least something to implement to satisfy this conditions?
I have to following endpoint structure in Jersey:
/objects/
/objects/:id
/objects/:id/:field
/objects/:id/:field/:subfield
The IDs I'm using have a very specific format, so I first check if the format is valid before making a request to the database.
Right now I have to put this code in each of the POST, PUT, GET, DELETE functions for each of the functions that has :id as a parameter. So this just means an early return.
if (!isIdValid(id)){
return Response.status(Response.StatusType.BAD_REQUEST)
.entity("The ID you've provided is invalid")
.build();
}
(In reality the error entity is an object containing more information about the error)
And then for each function using the :field or :subfield parameters the code is similar. This checking and error-handling behavior has to be copied every time. And when I start copy-pasting stuff, I start thinking: there should be a better way?
I would like to place the :id checking code at the the /objects/:id level, and then all further nested levels are assumed have a valid ID. The same for the other parameters further nesting down.
I've been looking into using subresource locators, but then you create a function returning a new instance of the subresource. I can't put a conditional return of a Response-object at that level for if the validation fails.
#Path("{id}")
function Class<ObjectFieldResource> getObjectById(#PathParam("id") String id){
return ObjectFieldResource.class;
}
I could start throwing exceptions, but I would rather avoid that, since I don't really consider invalid input to be an exception.
How would such a structure best be implemented? I've looked at bean validation but that doesn't seem to allow me to define validation for my specific format + custom error responses.
Am I missing something in the way subresources should be implemented?
Solution 1
If you can use regexp checks instead of your isIdValid method it's possible to define your resources like this
#POST
#Path("objects/{id:\\d+}")
public Response doSmth(#PathParam("id") String id) {
...
}
In a case of invalid id format caller will have 'Not Found' response status without even reaching your doSmth method.
Obviously, you can use String constants for all equal path values.
final static String ID_RES = "objects/{id:\\d+}";
#POST
#Path(ID_RES)
public Response postSmth(#PathParam("id") String id) {
...
}
...
#GET
#Path(ID_RES)
public Object getSmth(#PathParam("id") String id) {
...
}
The can also read full description of Path#value parameter
Solution 2
Create and register at your REST server javax.ws.rs.container.ContainerRequestFilter implementation with filter method having needed URI checks.
The single filter parameter has ContainerRequestContext type from witch you can call getUriInfo for getting URI and method abortWith(Response response) which can be used for aborting caller request if your resource ids validation was failed.
See Chapter 10. Filters and Interceptors chapter of Jersey Manual.
Code
I have my Controller method like this:
#RequestMapping("/{userId}/{configId}")
def edit(#PathVariable("userId") User user,
#PathVariable("configId") Configuration configuration) {
/* some code here*/
}
When I call this method from my browser it works very well, and user, and configuration args bind from DataBase by their id.
Problem
But, when I used MvcUriComponentsBuilder class, I got some exceptions for incorrect arguments type in the expected method.
MvcUriComponentsBuilder.fromMethodName(MyController.class, "edit", 1, 2).build()
Exception
java.lang.IllegalArgumentException: source to convert from must be an instance of #org.springframework.web.bind.annotation.PathVariable User; instead it was a java.lang.Long
Faced some body with similar problem? Are there any solution?
NOTE: I'm currently using Spring Web MVC 4.1.8.RELEASE
A bit more descriptions
I'm using MvcUriComponentsBuilder in Thymeleaf template like this:
th:action="${#mvc.url('CC#edit').arg(0, configuration.access.id).arg(1, configuration.id).build()}
As docs says that in arg method should be passed native method arg (in my example should passed User and Configuration instances). But, in my opinion better solution is using long values (for example) and then autobind it to object as it expected (as like it works over browser call)
Additional info!
I listened to #Sotirios Delimanolis, and use this function as it described in it docs
th:action="${#mvc.url('CC#edit').arg(0, configuration.access.user).arg(1, configuration).build()
Passed arguments are correct in this example.
BUT, I have gotten exception AGAIN!
org.springframework.core.convert.ConverterNotFoundException: No converter found capable of converting from type #org.springframework.web.bind.annotation.PathVariable #org.springframework.web.bind.annotation.ModelAttribute ua.smartsteamshop.web.app.domain.User to type java.lang.String
It is looks like a bug! Guys, I need your help! This question should be discussed!
This question already has answers here:
JAX-RS: Multiple paths
(4 answers)
Closed 2 years ago.
Can we have more than one #Path annotation for same REST method i.e. the method executed is the same, but it is executed on accessing more than one URL?
E.g.: I want to run the searchNames() method on both http://a/b/c and http://a/b.
You can't have mutliple #Path annotations on a single method. It causes a "duplicate annotation" syntax error.
However, there's a number of ways you can effectively map two paths to a method.
Regular expressions in #Path annotation
The #Path annotation in JAX-RS accepts parameters, whose values can be restricted using regular expressions.
This annotation:
#Path("a/{parameter: path1|path2}")
would enable the method to be reached by requests for both /a/path1 and /a/path2. If you need to work with subpaths, escape slashes: {a:path1\\/subPath1|path2\\/subPath2}
Serving responses with a redirection status code
Alternatively, you could set up a redirection. Here's a way to do it in Jersey (the reference implementation of JAX-RS), by defining another subresource. This is just an example, if you prefer a different way of handling redirections, feel free to use it.
#Path("basepath")
public class YourBaseResource {
//this gets injected after the class is instantiated by Jersey
#Context
UriInfo uriInfo;
#Path("a/b")
#GET
public Responce method1(){
return Response.ok("blah blah").build();
}
#Path("a/b/c")
#GET
public Response method2(){
UriBuilder addressBuilder = uriInfo.getBaseUriBuilder();
addressBuilder.path("a/b");
return Response.seeOther(addressBuilder.build()).build();
}
}
Using a servlet filter to rewrite URLs
If you're going to need such functionality often, I suggest intercepting the incoming requests using a servlet filter and rewriting the paths on the fly. This should help you keep all redirections in one place. Ideally, you could use a ready library. UrlRewriteFilter can do the trick, as long as you're fine with a BSD license (check out their google code site for details)
Another option is to handle this with a proxy set up in front of your Java app. You can set up an Apache server to offer basic caching and rewrite rules without complicating your Java code.
As explained in Tom's answer, you can not use more than one #Path annotation on a single method, because you will run into error: duplicate annotation at compile time.
I think the simplest way to get around this is to use method overloading:
#Path("{foo}")
public Response rest(#PathParam("foo") final String foo) {
return this.rest(foo, "");
}
#Path("{foo}/{bar}")
public Response rest(#PathParam("foo") final String foo,
#PathParam("bar") final String bar) {
return Response.ok(foo + " " + bar).build();
}
You could also use more different method names if you run into the case where multiple overloaded methods have the signature.
Another solution for your particular example:
http://a/b/c
http://a/b
Let's suppose that:
/a is for the resource class
/b/c and /b are the paths for the methods
because a full path looks like:
<protocol><host><port><app><url-pattern><resource-path><method-path>.
Use optional parameter
#Path("/b{c : (/c)?}")
public Response searchNames(#PathParam("c") String val) {
...
}
The example above works for all examples like:
/b
/b/
/b/c
/b/c/
but when c is provided, the val is /c (it has a / before).
If you want to fix the problem above (to avoid Java parsing), you need something more complex:
#Path("/b{slash : (/)?}{c:((?<=/).*)?}")
which will return only c (not /c) for the 3rd bullet point, but for the 4th bullet point it will return c/ which has to be parsed in Java.
But for your case ("the method executed is the same"), don't worry about parsing because you don't have different actions.
If you are using Spring then try
#RequestMapping(value = {"/def", "/abc"}, method = RequestMethod.POST)
This will work for both /abc and /def.
– sSaroj Nov 17 '17 at 10:13