Retrofit - @Body parameters cannot be used with form or multi-part encoding

Question

I m trying to make a request in which I want to include a Header , a form-urlencoded field and a json body. My Retrofit interface is as follows

@FormUrlEncoded
@POST("/api/register")
Observable<RegisterResponse> register(
    @Header("Authorization") String authorization, 
    @Field("grant_type") String grantType, 
    @Body RegisterBody body
);

When I make this request I get back exception @Body parameters cannot be used with form or multi-part encoding.
I have also tried with the @Multipart annotation:

@Multipart
@FormUrlEncoded
@POST("/api/register")
Observable<RegisterResponse> register(
    @Header("Authorization") String authorization, 
    @Part("grant_type") TypedString grantType, 
    @Body RegisterBody body
);

and I get an IllegalArgumentException and only one encoding annotation is allowed.

possible duplicate of [Multipart Request using Retrofit 1.8.0 not working](http://stackoverflow.com/questions/21582453/multipart-request-using-retrofit-1-8-0-not-working) — njzk2, Dec 05 '14 at 16:21
also, since it is a multipart, you need several @Part, not a Body and a Part — njzk2, Dec 05 '14 at 16:22

score 114 · Answer 1 · edited Dec 24 '22 at 02:29

114

maybe this could help some people, if you have this trouble, you should remove @FormUrlEncoded of your interface.

edited Dec 24 '22 at 02:29

starball

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answered Apr 19 '16 at 08:26

Julien Athomas

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11

`@Multipart` would cause the same problem, too! – Alireza Noorali Sep 30 '18 at 15:58

score 25 · Accepted Answer · edited May 23 '17 at 12:26

25

This post pointed me to the right direction https://stackoverflow.com/a/21423093/1446856. I attached everything in the body and send it as a TypedInput.
So the interface looks something like this

@POST("/api/register")
@Headers({ "Content-Type: application/json;charset=UTF-8"})
Observable<RegisterResponse> register(
    @Header("Authorization") String authorization,
    @Body TypedInput body
);

and the body looks something like this

String bodyString = jsonBody + "?grant_type=" + 
    grantType + "&scope=" + scope;
TypedInput requestBody = new TypedByteArray(
    "application/json", bodyString.getBytes(Charset.forName("UTF-8")));

edited May 23 '17 at 12:26

Community

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answered Dec 08 '14 at 09:47

Chris

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what's the value for 'jsonBody'? – ViksaaSkool Jul 28 '15 at 08:51
@ViksaaSkool it can be any json string. for instance {"currency":"GBP", "customerId":2, "country":"GB", "lang":"en-GB", "sizeSchema":"UK", "store":"1"} – Chris Aug 05 '15 at 07:57
2

This one not works in Retrofit 2 , we should use RequestBody !! – LOG_TAG Jul 24 '16 at 19:48
what is the value for the bodyString ? or how to achieve this in retrofit 2 ? – Dhiren Basra Jul 07 '17 at 13:50

score 9 · Answer 3 · answered Sep 29 '20 at 12:24

Adding to Julien's answer, also remove the @Multipart annotation. Here's how I have used it:

@POST("/app/oauth/token")
Call<AuthResponse> getAuthToken(@Body RequestBody body);

And, here is how I have constructed the RequestBody:

RequestBody requestBody = new MultipartBody.Builder()
                        .setType(MultipartBody.FORM)
                        .addFormDataPart("grant_type", "password")
                        .addFormDataPart("username", username)
                        .addFormDataPart("password", password)
                        .build();

Cleaner and easier than the accepted answer, works like a charm. — Dantalian, Jan 28 '21 at 14:25

score 1 · Answer 4 · edited Apr 20 '17 at 09:55

1

I solved this problem by adding the field into

@POST("/api/register")

like this:

@POST("/api/register?grantType=value")

it's not a good solution, but may be useful.

edited Apr 20 '17 at 09:55

Pedro del Sol

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answered Apr 20 '17 at 09:27

Matt.Young

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score 0 · Answer 5 · answered Dec 09 '18 at 08:12

Send Authentication header with json Body to API sample code in Kotlin :

 @POST("/api/user/sendlist/")
    fun callSendJsonListPost(
                      @Header("Authheader") header: String,
                      @Body list: StringBuilder
                      )
        : Observable<EntityModelUserslist>

Retrofit - @Body parameters cannot be used with form or multi-part encoding

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