Support uploading and downloading files

[zdd248]

EXAMPLE:

val upload = post |>
  operation('download) |>
  formField[(FileInfo, Source[ByteString, Any])]('file) |>
  $$[String]

val download = get |>
  operation(Symbol("download")) |>
  $$[File]

AKKA HTTP DOCUMENTATION:

fileUpload
https://doc.akka.io/docs/akka-http/current/routing-dsl/directives/file-upload-directives/fileUpload.html

getFromFile
https://doc.akka.io/docs/akka-http/current/routing-dsl/directives/file-and-resource-directives/getFromFile.html

[zdd248]

Swagger 3.0 specification for file upload
https://swagger.io/docs/specification/describing-request-body/file-upload/

ONE FILE

Swagger:

requestBody:
  content:
    multipart/form-data:
      schema:
        type: object
        properties:
          orderId:
            type: integer
          userId:
            type: integer
          fileName:
            type: string
            format: binary

Http Request:

POST /upload
Host: example.com
Content-Length: 2740
Content-Type: multipart/form-data; boundary=----WebKitFormBoundaryWfPNVh4wuWBlyEyQ
------WebKitFormBoundaryWfPNVh4wuWBlyEyQ
Content-Disposition: form-data; name="orderId"
1195
------WebKitFormBoundaryWfPNVh4wuWBlyEyQ
Content-Disposition: form-data; name="userId"
545
------WebKitFormBoundaryWfPNVh4wuWBlyEyQ
Content-Disposition: form-data; name="fileName"; filename="attachment.txt"
Content-Type: text/plain
[file content goes there]
------WebKitFormBoundaryWfPNVh4wuWBlyEyQ

ARRAY FILE

Swagger:

requestBody:
  content:
    multipart/form-data:
      schema:
        type: object
        properties:
          filename:
            type: array
            items:
              type: string
              format: binary

Http Request:

POST /upload
Host: example.com
Content-Length: 2740
Content-Type: multipart/form-data; boundary=----WebKitFormBoundaryWfPNVh4wuWBlyEyQ
------WebKitFormBoundaryWfPNVh4wuWBlyEyQ
Content-Disposition: form-data; name="fileName"; filename="file1.txt"
Content-Type: text/plain
[file content goes there]
------WebKitFormBoundaryWfPNVh4wuWBlyEyQ
Content-Disposition: form-data; name="fileName"; filename="file2.png"
Content-Type: image/png
[file content goes there]
------WebKitFormBoundaryWfPNVh4wuWBlyEyQ
Content-Disposition: form-data; name="fileName"; filename="file3.jpg"
Content-Type: image/jpeg
[file content goes there]
------WebKitFormBoundaryWfPNVh4wuWBlyEyQ