RicoSuter/NSwag

Generating ASP.NET Core Controllers, FileParameter vs. IFormFile

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#2,075 opened on Apr 3, 2019

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help wantedproject: NSwag.CodeGeneration.CSharp (Controllers)

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Description

In my OpenAPI 2.0 specification, I have the following portion of code for having a file upload available:

   consumes:
    - multipart/form-data
  parameters:
    - in: formData
      name: someFile
      type: file
      required: true
      description: Some file

The generated ASP.NET Core code for the controller contains the definition of a class "FileParameter" that is also passed in to the controller method as an argument. There two problems:

  1. The given definition of the FileParameter class does not contain a parameterless constructor, which causes the model binding of ASP.NET to fail. If I add such a constructor:
  2. The model binding does not seem to function properly in this case, the method receives a FileParameter object. However, its fields are initialized with null.

Changing the FileParameter class manually to IFormFile fixes these issues. Is there some other way to make this work? Or is it unsupported currently?

Contributor guide

Research direction
Examine how NSwag generates the FileParameter class and why it lacks parameterless constructor; compare with ASP.NET Core's IFormFile binding and explore options to customize generation.
Tech stack
csharp
Domain
backend
Issue type
Bug
DifficultyEstimated implementation difficulty for a new contributor, from 1 for very small changes to 5 for expert-level work.
3
Estimated timeA rough time range for an experienced contributor to investigate, implement, test, and prepare a pull request.
1-3 hours
Activity statusHow available the issue appears right now: fresh, active, stale, blocked, or waiting on maintainer input.
Active
ClarityHow clearly the issue explains the expected change, acceptance criteria, and next step.
Clear
Prerequisites
C#ASP.NET Core
Newbie friendlinessA 1-100 score estimating how approachable this issue is for first-time contributors.
65