Swagger WebAPI JSON Object formatting standards between C#, TypeScript and Others

When designing objects in C# you use pascal casing for your properties, but in other languages you don’t, and example (other than java) is TypeScript here’s an article from Microsoft about it.

And that’s cool, a lot of the languages have different standards and depending on which one you are in, you write a little different.

The problem is when you try to work on a standard that defines cross platform communication that is case sensitive, an example being Swagger using REST and JSON.

So the issue we had today was a WebAPI project was generating objects like this:

"ObjectId": 203
"ObjectName" : "My Object Name"

When swaggerated the object comes out correctly with the correct pascal casing, however when using swagger codegen the object is converted to camel case (TypeScript Below)

export interface MyObject {
 objectId: number;
 objectName: string;

The final output is a generated client library that can’t read any objects from the API because JavaScript is case sensitive.

After some investigation we found that when the swagger outputs camel casing the C# client generators (Autorest and Swagger codegen) will output C# code that is in camel casing but with properties to do the translating from camel to pascal, like the below example

/// <summary>
/// Gets or Sets TimeZoneName
/// </summary>
[JsonProperty(PropertyName = "timeZoneName")]
public string TimeZoneName { get; set; }

So to avoid pushing shit up hill we decided to roll down it. I found this excellent article on creating a filter for WebAPI to convert all your pascal cased objects to camel case on the fly

So we found that the best practice is:

  • Write Web API C# in Pascal casing
  • Covert using an action filter from pascal to camel case Json objects
  • Creating the client with TyepScript (or other camel language) default option will then work
  • Creating the C# client will add the JsonProperty to translate from camel to pascal and resulting C# client will be pascal cased

I raised a GitHub Issue here with a link into the source code that I found in swagger codegen, however later realized that changing the way we do things will mitigate long term pain.

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