requestInterceptor that returns promise breaks curlify output

Q&A (please complete the following information)

• OS: Windows 10
• Browser: Chrome
• Version: 67.0.3396.99
• Method of installation: dist assets
• Swagger-UI version: 3.17.6
• Swagger/OpenAPI version: OpenAPI 3.0

Content & configuration

Example Swagger/OpenAPI definition:

openapi: 3.0.0
info:
  version: 1.0.0
  title: Swagger Petstore
  license:
    name: MIT
servers:
  - url: 'http://petstore.swagger.io/v1'
paths:
  /pets:
    get:
      summary: List all pets
      operationId: listPets
      tags:
        - pets
      responses:
        '200':
          description: An paged array of pets
          headers:
            x-next:
              description: A link to the next page of responses
              schema:
                type: string

Swagger-UI configuration options:

SwaggerUI({
          url: "https://api.myjson.com/bins/1h15yo",
          dom_id: '#swagger-ui',
          deepLinking: true,
          presets: [
            SwaggerUIBundle.presets.apis,
          ],
          plugins: [
            SwaggerUIBundle.plugins.DownloadUrl,
          ],
          requestInterceptor: req => {
            //return req;
            return new Promise((resolve, reject) => resolve(req));
          }
})

Describe the bug you’re encountering

When using a requestInterceptor that returns a promise (that resolves to the request), instead of the pure request, the curl statement generated with curlify results in curl -X "undefined". Although the modified request is being used to send the http request.

To reproduce…

Steps to reproduce the behavior:

1. See this jsfiddle: https://jsfiddle.net/falxfalx/6xy24zL9/32/
2. Press play
3. Try it out on GET /pets
4. Execute
5. Observe generated curl request
6. Now comment requestInterceptor return statement and uncomment the return req; line
7. Repeat step 2 through 5 (this is expected behaviour)

Expected behavior

The displayed curl request should not be undefined.

Additional context or thoughts

Since I saw that curlify.js has a curl function that is to be called with the request as argument, I suspect that when returning a promise, the curlify call becomes: curl(promise) while it should be something like:

const req = await promise;
curl(req);

[copitz]

If the request url isn’t changed by requestInterceptor asynchronously this issue can be worked around like this:

SwaggerUI({
          // ...
          requestInterceptor: req => {
            //return req;
            const promise = new Promise((resolve, reject) => resolve(req));
            promise.url = req.url
            return promise
          }
})

[restfulhead]

Adding showMutatedRequest: false to the config seems to work for me. Without this option I’m seeing the same issue with the curl output.