Editing question with more details :
I understand the use of service interfaces in Retrofit. I want to make a call to a URL like this :
http://a.com/b/c (and later append query parameters using a service interface).
My limitations are :
I cannot use /b/c as a part of service interface (as path parameter). I need it as a part of base url. I have detailed the reason below.
I cannot afford to have a resultant call being made to http://a.com/b/c/?key=val. What I need is http://a.com/b/c?key=val (the trailing slash after "c" is creating problems for my API). More details below.
My Server API changes pretty frequently, and I am facing trouble on the client side using Retrofit. The main problem is that we cannot have dynamic values (non final) passed to #GET or #POST annotations for Path Parameters (like it is possible for query parameters). For example, even the number of path parameters change when the API changes. We cannot afford to have different interfaces everytime the API changes.
One workaround to this is by forming the complete URLs, that is, an Endpoint with Base_Url + Path_Parameters.
But I am wondering why is Retrofit forcibly adding a trailing slash ("/") to the base url :
String API_URL = "https://api.github.com/repos/square/retrofit/contributors";
if (API_URL.endsWith("/")) {
API_URL = API_URL.substring(0, API_URL.length() - 1);
}
System.out.println(API_URL); //prints without trailing "/"
RestAdapter restAdapter = new RestAdapter.Builder()
.setEndpoint(API_URL)
.build();
API_URL is always being reset to https://api.github.com/repos/square/retrofit/contributors/ by Retrofit internally (confirmed this by logging the request)
One workaround to this is by manually adding a "?" in the end to prevent "/" to be added: https://api.github.com/repos/square/retrofit/contributors?
Unfortunately, such request won't be accepted by our API.
Why is Retrofit forcing this behavior ?
Is there a solution for people like me who don't want a trailing slash ?
Can we have variable parameters (non final) being passed to Retrofit #GET or #POST annotations ?
You're expected to pass the base URL to the setEndpoint(...) and define /repos/... in your service interface.
A quick demo:
class Contributor {
String login;
#Override
public String toString() {
return String.format("{login='%s'}", this.login);
}
}
interface GitHubService {
#GET("/repos/{organization}/{repository}/contributors")
List<Contributor> getContributors(#Path("organization") String organization,
#Path("repository") String repository);
}
and then in your code, you do:
GitHubService service = new RestAdapter.Builder()
.setEndpoint("https://api.github.com")
.build()
.create(GitHubService.class);
List<Contributor> contributors = service.getContributors("square", "retrofit");
System.out.println(contributors);
which will print:
[{login='JakeWharton'}, {login='pforhan'}, {login='edenman'}, {login='eburke'}, {login='swankjesse'}, {login='dnkoutso'}, {login='loganj'}, {login='rcdickerson'}, {login='rjrjr'}, {login='kryali'}, {login='holmes'}, {login='adriancole'}, {login='swanson'}, {login='crazybob'}, {login='danrice-square'}, {login='Turbo87'}, {login='ransombriggs'}, {login='jjNford'}, {login='icastell'}, {login='codebutler'}, {login='koalahamlet'}, {login='austynmahoney'}, {login='mironov-nsk'}, {login='kaiwaldron'}, {login='matthewmichihara'}, {login='nbauernfeind'}, {login='hongrich'}, {login='thuss'}, {login='xian'}, {login='jacobtabak'}]
Can we have variable parameters (non final) being passed to Retrofit #GET or #POST annotations ?
No, values inside (Java) annotations must be declared final. However, you can define variable paths, as I showed in the demo.
EDIT:
Note Jake's remark in the comments:
Worth noting, the code linked in the original question deals with the case when you pass https://api.github.com/ (note the trailing slash) and it gets joined to /repos/... (note the leading slash). Retrofit forces leading slashes on the relative URL annotation parameters so it de-dupes if there's a trailing slash on the API url.
Related
I use Retrofit for most of my calls but in one of the cases, I have the full path provided in arguments. My URL is like this http://www.example.com/android.json. This URL is provided in full so I have to path it at runtime. I implement endpoint as suggested here
https://medium.com/#kevintcoughlin/dynamic-endpoints-with-retrofit-a1f4229f4a8d
but in the #GET I need to be able to put #GET(""). This does not work as I get an error saying I should provide at least one "/".
If I add the slash the URL becomes http://www.example.com/android.json/ and it does not work, the server returns forbidden. I also tried creating a custom GET interface similar to here https://github.com/square/retrofit/issues/458 but with GET and without providing a value method in the interface. Then I get another error saying value is missing.
Basically I need to be able to provide an empty or null value but retrofit does not allow that. How could I solve this problem? For now I am doing the JSON request manually but is there a way I could use retrofit for this case? I need to pass the full URL there is no way I can do endpoint http://www.example.com and #GET("/android.json").
Thanks
You can use #GET(".") to indicate that your url is the same as the base url.
#GET(".")
Observable<Result> getData(#Query("param") String parameter);
I've tried this approach, however didn't work for me.
Workaround for this issue is:
//Retrofit interface
public interface TestResourceClient {
#GET
Observable<Something> getSomething(#Url String anEmptyString);
}
//client call
Retrofit.Builder().baseUrl("absolute URL").build()
.create(TestResourceClient.class).getSomething("");
The downside of this solution is that you have to supply empty string in getSomething("") method call.
I face the same problem with Retrofit 2. Using #GET, #GET("") and #GET(".") not solved my problem.
According to the official document you can the same baseUrl and #GET argument.
Endpoint values may be a full URL.
Values that have a host replace the host of baseUrl and values also with a scheme replace the scheme of baseUrl.
Base URL: http://example.com/
Endpoint: https://github.com/square/retrofit/
Result: https://github.com/square/retrofit/
So in my case:
interface MyAPI {
#GET("http://www.omdbapi.com/")
suspend fun getMovies(
#Query("apikey") apikey: String,
#Query("s") s: String
): Response<MoviesResponse>
companion object {
operator fun invoke(): MyAPI {
return Retrofit.Builder()
.addConverterFactory(GsonConverterFactory.create())
.baseUrl("http://www.omdbapi.com/")
.build()
.create(MyAPI::class.java)
}
}
}
This day is the first time for me to use dotNet web API for my project.
This is the code of my controller
public IEnumerable<Waybill> Get(string id_wb) {
List<Waybill> lstWaybill = new List<Waybill>();
lstWaybill = objway.GetWaybill(id_wb).ToList();
return lstWaybill;
}
That API can work well if I'm call using this link :
http://localhost:56127/api/waybill/?id_wb=00000093
but I don't know how to call that link from my android app (I'm using retrofit)
#GET("Waybill/{id_wb}/id_wb")
Call<Waybill> getWaybillData(#Path("id_wb") String id_wb);
There are 3 options.
First one is to use Retrofit's #Query annotation.
#GET("Waybill/")
Call<Waybill> getWaybillData(#Query("id_wb") String id_wb);
The second one is to #Path annotation
#GET("Waybill/?id_wb={id_wb}") // notice the difference in your code and my code
Call<Waybill> getWaybillData(#Path("id_wb") String id_wb);
The third option is to use #Url annotation. With this option, you need to prepare fully qualified URL before calling/using getWaybillData() method in your activity or fragment. Keep in mind that #Url method overrides base URL set in Retrofit client.
#GET // notice the difference in your code and my code
Call<Waybill> getWaybillData(#Url String completeUrl);
If you follow 3rd option you need to prepare full URL in your activity like below.
String url = "http://<server_ip_address>:56127/api/waybill/?id_wb=00000093";
YourInterface api = ...
Call<Waybill> call = api.getWaybillData(url);
call.enqueue({/* implementation */});
I see a difference in the sample URL you mentioned and usage in Retrofit API interface.
In sample URL waybill is small and in API interface it is Waybill. Please ensure that you're using the right URL.
I am trying to make an API call to a mobile backend with Retrofit 2.0. In my API call, i have to make necessary call to this URL
https://api.backendless.com/v1/data/Users?where=followings.objectId=%270B3BA7F9-260F-B378-FF9A-3C2448B8A700%27
To form this URL in Retrofit i have been using below interface
#GET("Users?where=")
Call<List<User>> getFollowers(#Query("followings.objectId") String objectId);
This interface call puts an ampersand before the query parameters and generates a URL like below
https://api.backendless.com/v1/data/Users?where=&followings.objectId=%270B3BA7F9-260F-B378-FF9A-3C2448B8A700%27
I tried to overcome this with Path annotation but i keep getting "URL query string must not have replace block. For dynamic query parameters using #Query" error.
API that i am trying to connect requires a "where=" clause for filtering by design. I have no permission to change that. What i want is somehow tell Retrofit not to put an ampersand sign before the query parameter or any workarounds for this issue.
Any help is appreciated.
For those who seek for similar answers, I came up with below solution
I declared my interface with #Url
#GET
Call<List<User>> getFollowers(#Url String objectId);
and generated related URL part as an extension method
public String toFollowerRequest(){
return RestGlobals.BASE_URL + "Users?where=followings.objectId=%27" + objectId + "%27";
}
#GET("{path}")
Call> getFollowers(#Path("path") path, #Query("followings.objectId") String objectId);
getFollowers("Users?where=", ...)
I wanted to use retrofit library for parsing and posting the data by passing some parameters. But When defining model class some times we will use #Serialized in-front of variable, What is the use of that Serialized.And What is the difference between #Get and #Query in passing params to API.Can Any one explain the difference.
Lets say you have api method #GET("/api/item/{id}/subitem/") so by using #Path("id") you can specify id for item in path. However your api may take additional parameters in query like sort, lastupdatetime, limit etc so you add those at end of url by #Query(value = "sort") String sortQuery
So full method will look like:
#GET("/api/item/{id}/subitem")
SubItem getSubItem(#Path("id") int itemId, #Query("sort") String sortQuery, #Query("limit") int itemsLimit);
and calling api.getSubItem(5, "name", 10) will produce url #GET("/api/item/5/subitem/?sort=name&limit=10")
and #Get is HTTP method
http://www.w3schools.com/tags/ref_httpmethods.asp says
Two commonly used methods for a request-response between a client and
server are: GET and POST.
GET - Requests data from a specified resource POST - Submits data to
be processed to a specified resource
#GET is request method. You mark method with that.
#Query is query parameter (i.e. the one in the URL). You mark method parameters with that.
#Serialized probably does not belong to Retrofit, look at its package name (move cursor there and press `Ctrl+Q in Android studio)
I would like to always add a parameter to my Retrofit calls. For values that I can hard code I can simply use
#POST("/myApi?myParam=myValue")
but what if I want to append android.os.Build.MODEL?
#POST("/myApi?machineName="+ Build.MODEL)
doesn't work. It would be useful to be able to abstract this part of the network call away from the implementing code.
EDIT
I can add Build.MODEL to all of my api calls by using a RequestInterceptor. However it still eludes me how to add it selectively to only some of my api calls while still using the same RestAdapter.
EDIT 2
Fixed the title which was all sorts of wrong.
EDIT 3
Current implementation:
RestAdapter restAdapter = new RestAdapter.Builder()
.setEndpoint("myapi")
.setRequestInterceptor(new RequestInterceptor() {
#Override
public void intercept(RequestInterceptor.RequestFacade request) {
request.addQueryParam("machineName", Build.MODEL);
}
})
.build();
API_SERVICE = restAdapter.create(ApiService.class);
Build.MODEL is not available for use in an annotation because it cannot be resolved at compile time. It's only available at runtime (because it loads from a property).
There are two ways to accomplish this. The first is using a RequestInterceptor which you mention in the question.
The second is using a #Query parameter on the method.
#POST("/myApi")
Response doSomething(#Query("machineName") String machineName);
This requires you to pass Build.MODEL when invoking the API. If you want, you can wrap the Retrofit interface in an API that's more friendly to the application layer that does this for you.