GET request with request body in OkHttp

Question

I'm trying to use OkHttp 3.6.0 with Elasticsearch and I'm stuck with sending requests to the Elasticsearch Multi GET API.

It requires sending an HTTP GET request with a request body. Unfortunately OkHttp doesn't support this out of the box and throws an exception if I try to build the request myself.

RequestBody body = RequestBody.create("text/plain", "test");

// No RequestBody supported
Request request = new Request.Builder()
                  .url("http://example.com")
                  .get()
                  .build();

// Throws: java.lang.IllegalArgumentException: method GET must not have a request body.
Request request = new Request.Builder()
                  .url("http://example.com")
                  .method("GET", requestBody)
                  .build();

Is there any chance to build a GET request with request body in OkHttp?

Related questions:

• HTTP GET with request body
• How to make OKHTTP post request without a request body?
• Elasticsearch GET request with request body

Answer 1

I found a solution for this problem after a few attempts. Maybe someone finds it useful.

I made use of "Httpurl.Builder."

HttpUrl mySearchUrl = new HttpUrl.Builder()
       .scheme("https")
       .host("www.google.com")
       .addPathSegment("search")
       .addQueryParameter("q", "polar bears")
       .build();

Your get request url will happen exactly this way:

https://www.google.com/search?q=polar%20bears

And after building your url you have to build your request like this:

Request request = new Request.Builder()
                        .url(mySearchUrl)
                        .addHeader("Accept", "application/json")
                        .method("GET", null)
                        .build();

Here is the source: https://square.github.io/okhttp/3.x/okhttp/okhttp3/HttpUrl.html

Answer 2

I tried to achieve the same, but unfortunately, it cannot be done without dirty tricks I personally admire as an exercise but don't want to see in my production code.

Basically, you can create POST method with a builder and set its method field to "GET" later using the reflection. This will do the trick.

Something like this:

Builder builder = new Request.Builder().url(mySearchUrl).method("POST", body).build();
Field field = Builder.class.getField("method");
field.setAccessible(true);
field.setValue(builder, "GET");

Answer 3

Technically RFC https://tools.ietf.org/html/rfc2616#section-9.3 says you can use the body in the get request.

What I tried before switching to another client library

1. I tried request rewriting using network interceptor

2. I tried reflection to change the method

       Field field = originalRequest.getClass().getDeclaredField("method");
       field.setAccessible(true);
       field.set(originalRequest, "GET");
   

Conclusion: You will need to change the library, OKHttp doesn't have support for GET request with requests body, need to use apache client or any other client which supports this.

Answer 4

If the base API allow query params, send all the body params as queryparams. It works like a charm. While OKHttp allow the query params but will not allow body with Get calls to avoid cache inconsistencies.

Answer 5

do both. (in order)

Request request = new Request.Builder()
                  .url("http://example.com")
                  .post(requestBody)
                  .get()
                  .build();