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How to send request body in get method retrofit

I am using the retrofit library for network calls. In this, I need to pass Body in GET Method. But I am getting the error while I am passing this one. In Postman it is working while passing Body for GET Method.
#GET("http://192.168.0.141:3000/api/contacts/{page_num}/{limit}")
fun getAllContacts(#Path("page_num") page_num:Int,#Path("limit") limit:Int,#Body reqBody:ContactsInpRequest):Call<AllContactsDataResponse>
I am calling get method by passing body. But I am getting the below exception.
java.lang.IllegalArgumentException: Non-body HTTP method cannot contain #Body.

GET method does not contain body like the POST does. Here you can learn more about REST methods: https://restfulapi.net/http-methods/
EDIT: I see that you said that it works in Postman so take a look at this:
*CAN GET request have a body?
In other words, any HTTP request message is allowed to contain a message body, and thus must parse messages with that in mind. Server semantics for GET, however, are restricted such that a body, if any, has no semantic meaning to the request. ... Yes, you can send a request body with GET but it should not have any meaning.*

java.lang.IllegalArgumentException: Non-body HTTP method cannot contain #Body
This means your #GET or #DELETE should not have #Body parameter. You can use query type url or path type url or Query Map to fulfill your need. Else you can use other method annotation.

#Headers("Content-Type: application/json")
#GET("helper-url")
fun getHelperUrl(
#Query("api_token") apiToken: String,
#Query("authtype") authType: String,
#Query("channel") channel: String
): Call<ResponseHelperUrl>

What is the difference between #Field and #Query in retrofit

In some POST requests, I don't know when to use #Field with FormUrlEncoded and when to use #Query
For Example:
#POST("list-products-for-sale")
Call<ListAllProductsResponse> getNewProducts(#HeaderMap Map<String,
String> headers,#Query("lastProductId") String lastProductId);
When I tried to use #Field here it was not responding properly and when I switched it to #Query it's working great.
I want to know why #Field isn't working while Query can work perfectly and I did tested in POSTMAN where I sent the data as a formurlencoded and it's giving me the results fin.
EDIT
BTW I'm passing Content-Type:application/json, Accept: application/json with an Authorization key

#Field is used to send #FormUrlEncoded request in Retrofit which hides your parameter and not attach with url to provide security.Used for POST request.
#Query parameter appended to the URL.
If you are using #Field request than it will hides your parameter and not append with the url.
If you are using #Query request than all your parameter is append to your request and visible to users.
Depend on your api request you have to use one of above annotation. If the api request accept the #FormUrlEncoded data than use #Field or if they want to attached it with url than use #Query.
You can get more information from below link :
1) https://square.github.io/retrofit/2.x/retrofit/index.html?retrofit2/http/Query.html
2) https://square.github.io/retrofit/2.x/retrofit/retrofit2/http/Field.html

Using #Path and #Url paramers together with retrofit2

I'm using retrofit2 to comunicate with a webapi.
I need to set the URL of the webapi dynamically beacuase the user can change it, so i use the #Url annotation to specify it like this:
#POST
Call<LoginResponse> login(#Url String url, #Body LoginRequest user);
In one of the operations, i need to send some path parameters to the server, so i do this:
#GET
Call<DataResponse> getOrder(#Url String url,
#Header(WEBAPI_EMAIL_HEDER) String email,
#Header(WEBAPI_TOKEN_ID_HEDER) String token,
#Path("id") int id);
When i call the operation getOrder(...), an exception is rised by retrofit because i am not suppoused to use #Url and #Path parameters in the same operation.
This is the exception:
java.lang.IllegalArgumentException: #Path parameters may not be used with #Url. (parameter #4)
One solution is to replace the id parameter on the url and use only the #Url parameter in the invokation. But i think this is not the best way, beacuase i will be doing this with all the operations with #Path parameters.
Is there any other cleaner solution? Maybe using another retrofit2 annotation?
Thanks in advance.

As described in the post Retrofit 2 - Dynamic URL, the #Url notation assumes that the String is a fully defined URL and does not check whether it contains #Path variables.
To use the #Path annotation, you have to configure an endpoint URL and include the #Path variable inside the #GET() annotation.

There is a workaround. Incase of a dynamic Url with some variable path, we can define a string format with paths denoted by %s arguments.
E.g:
Suppose the dynamic url with path is : https://www.example.com/users/{id}/whoami
Here we can just replace {id} with %s. So now it becomes,
val formatString = https://www.example.com/users/%s/whoami
Now we can use it as a format string and replace it with required id.
val url = formatString.format(id)
and in the retrofit interface, use #Url parameter in the function.
interface AnyService {
fun whoAmI(#Url url:String): Call<ResponseBody>
}
Incase you are using MVVM architecture, you can call the formatting code in the concerned repository.

Retrofit GET without a value in Android

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)
}
}
}

Where in Retrofit build the full JSON before sending it?

I am using retrofit an get Bad Request , I would want to know if there is a place in this library where builds the full JSON in string format before sending it.

If it's about inspecting the JSON at runtime for debugging purposes, you can call setLogLevel(LogLevel.FULL) on your RestAdapter.Builder.
FULL logs the headers, body and metadata for both requests and responses to logcat.

new String(((TypedByteArray) request.getBody()).getBytes());

In order to build a JSON formatted body, create an object with a class whose properties are the same that you want to send to the server. The GSON Library set up (or whichever library you are using) with the RestAdapter should send the request with the body in JSON format.
Also ensure that the call is #POST annotated and the parameter annotd with #Body Below is an example:
#POST("/login")
User login(#Body LoginUser loginUser);