Response "Content type" drop-down sets HTTP "Accept" header

Using swagger-ui 3 and the petstore example, as deployed here: http://petstore.swagger.io.

For each operation, swagger-ui shows a list of response content types to choose from.

The list is populated from the “Produces” section in the OpenAPI (v2) specification file. For example:

"produces": [
        "application/json",
        "application/vnd.geo+json",
        "application/vnd.google-earth.kml+xml",
        "application/gml+xml",
        "application/text+csv"
    ],

Swagger-ui assumes that it should send an “Accept” header with a value of the selected content type with every request. This is not a good idea because not all APIs make use of the “Accept” header to specify the output format. For example, an API could instead use a query string parameter to specify output format. In that case, sending the “Accept” header is unnecessary, and the “Content Type” drop-down list is misleading because it doesn’t affect the response.

Ideally the OpenAPI Specification would provide a way to define how an API allows users to specify the output format. I’m not aware of a way in which OpenAPI v2 allows us to do this currently. Does anyone know if OpenAPI v3 will provide a way to do this?

In the mean time, can we have an option to remove the “Content Type” drop-down list (and its control of the “Accept” header) from swagger-ui?

[webron]

This is not going to be part of OAS3, and hopefully not a part of any other future versions. REST APIs are HTTP based, they use HTTP constructs. Content is negotiated using two headers - content-type for the payload, and accept for what the client expects to accept.

If you want to specify the content type using a query parameter, you’re welcome to do so, but the spec is not the right tool for the job. We’re not going to change the behavior. Of course, you’re welcome to write a plugin of your own to the system and change the behavior to suit your needs.

[DercilioFontes]

I created a solution that worked fine for me.

Uncommeted the OperationFilter with a class to empty the produces and add my Accept header parameters. And inject a JS file to remove all "response-content-type" divs. Code below.

Without that, the Accept header gets a application/json before my Accept parameter value ("application/json; charset=utf-8; version=v3") be added, resulting in: "application/json, application/json; charset=utf-8; version=v3" or "application/json, charset=utf-8; version=v3" if I remove the application/json from the my default settings. It gets a comma after the default response content type application/json. Even I also using comma in my accept parameter it does not work,. That breaks the server to get my controller version parameter.

The solution remove completely the default response content type application/json to get only my Accept header parameter settings.

// SwaggerConfig.cs

GlobalConfiguration.Configuration
                .EnableSwagger(c =>
                    {
                        c.OperationFilter<AddRequiredHeaderParameters>();

                    })
                    .EnableSwaggerUi(c =>
                    {
                        c.InjectJavaScript(thisAssembly, "Swashbuckle.Dummy.SwaggerExtensions.customJS.js");
                    });

// AddRequiredHeaderParameters.cs

public class AddRequiredHeaderParameters : IOperationFilter
    {
        public void Apply(Operation operation, SchemaRegistry schemaRegistry, ApiDescription apiDescription)
        {
            operation.produces = new string[0];
            
            if (operation.parameters == null)
                operation.parameters = new List<Parameter>();

            operation.parameters.Add(new Parameter
            {
                name = "client_id",
                @in = "header",
                type = "string",
                required = true
            });
            operation.parameters.Add(new Parameter
            {
                name = "Authorization",
                @in = "header",
                type = "string",
                required = true
            });
            operation.parameters.Add(new Parameter
            {
                name = "Accept",
                @in = "header",
                type = "string",
                @default = "application/json; charset=utf-8; version=v3",
                required = true
            });
        }
    }

// customJS.js

const respContentTypeDivs = document.querySelectorAll("div.response-content-type");
respContentTypeDivs.forEach(e => e.parentNode.removeChild(e));