Swagger TypeError: Failed to execute 'fetch' on 'Window': Request with GET/HEAD method cannot have body

Question

I have added Swagger to my Spring Boot 2 application:

This is my Swagger config:

@Configuration @EnableSwagger2 public class SwaggerConfig {      @Bean     public Docket api() {         // @formatter:off         return new Docket(DocumentationType.SWAGGER_2)                   .select()                                                   .apis(RequestHandlerSelectors.any())                               .paths(PathSelectors.any())                                           .build();         // @formatter:on     } } 

This is Maven dependency:

<!-- Swagger2 --> <dependency>     <groupId>io.springfox</groupId>     <artifactId>springfox-swagger2</artifactId>     <version>2.8.0</version> </dependency> <dependency>     <groupId>io.springfox</groupId>     <artifactId>springfox-swagger-ui</artifactId>     <version>2.8.0</version> </dependency> 

When I try to invoke for example http://localhost:8080/api/actuator/auditevents it fails with the following error:

TypeError: Failed to execute 'fetch' on 'Window': Request with GET/HEAD method cannot have body. 

What am I doing wrong and how to fix it ?

Answer 1

The error message actually says what the problem is. You post data with curl using the -d option while trying to use GET.

If you use the -d option curl will do POST.
If you use -X GET option curl will do GET.

The HTTP GET method is for requesting a representation of the specified resource. Requests using GET should only retrieve data and hence cannot have body.

More info on GET vs POST

Answer 2

I ran into this issue. Here is how I resolved it:

I had a method like this:

[HttpGet] public IEnumerable<MyObject> Get(MyObject dto) {       ... } 

and I was getting the error. I believe swagger UI is interpreting the Get parameters as FromBody, so it uses the curl -d flag. I added the [FromQuery] decorator and the problem was resolved:

[HttpGet] public IEnumerable<MyObject> Get([FromQuery]MyObject dto) {       ... } 

FYI this also changes the UI experience for that method. instead of supplying json, you will have a form field for each property of the parameter object.