[API Proposal]: Expose JsonContentOfT publicly

[ErisApps]

Background and motivation

The JsonContent<T> is currently marked as internal which makes it impossible to call (without the use of reflection). However, there are cases in which it could be useful to call the constructor on said class directly.
Eg: when constructing a JsonContent body for an instance while leveraging the newly-introduced source-generated JsonTypeInfo<T> for a PATCH API call.

Therefor I propose to mark said partial class as public instead of internal

API Proposal

namespace System.Net.Http.Json
{
-    internal sealed partial class JsonContent<TValue> : HttpContent
+    public sealed partial class JsonContent<TValue> : HttpContent
    {
        ...

        public JsonContent(TValue inputValue, JsonTypeInfo<TValue> jsonTypeInfo)
        {
            _typeInfo = jsonTypeInfo ?? throw new ArgumentNullException(nameof(jsonTypeInfo));
            _typedValue = inputValue;
            Headers.ContentType = JsonHelpers.GetDefaultMediaType();
        }

        ...
    }
}

API Usage

Won't change the usage internally, just exposes the class for use by external consumers.

var jsonContent = new JsonContent<TBody>(inputValue: body, jsonTypeInfo: jsonBodyTypeInfo);

Risks

I don't know why it was marked as internal in the first place. I assume it has a reason, but I can't really come up with one myself as I'm not familiar enough with the repository nor it's underlying architecture/internal workings.

It's not a breaking change at the very least as it's simply an addition to the public API surface. Maybe it affects trimmability though?

[ghost]

Tagging subscribers to this area: @dotnet/area-system-text-json
See info in area-owners.md if you want to be subscribed.

Issue Details

---

Background and motivation

The JsonContent<T> is currently marked as internal which makes it impossible to call (without the use of reflection). However, there are cases in which it could be useful to call the constructor on said class directly.
Eg: when constructing a JsonContent body for an instance while leveraging the newly-introduced source-generated JsonTypeInfo<T> for a PATCH API call.

Therefor I propose to mark said partial class as public instead of internal

API Proposal

namespace System.Net.Http.Json
{
-    internal sealed partial class JsonContent<TValue> : HttpContent
+    public sealed partial class JsonContent<TValue> : HttpContent
    {
        ...

        public JsonContent(TValue inputValue, JsonTypeInfo<TValue> jsonTypeInfo)
        {
            _typeInfo = jsonTypeInfo ?? throw new ArgumentNullException(nameof(jsonTypeInfo));
            _typedValue = inputValue;
            Headers.ContentType = JsonHelpers.GetDefaultMediaType();
        }

        ...
    }
}

API Usage

Won't change the usage internally, just exposes the class for use by external consumers.

var jsonContent = new JsonContent<TBody>(inputValue: body, jsonTypeInfo: jsonBodyTypeInfo);

Risks

I don't know why it was marked as internal in the first place. I assume it has a reason, but I can't really come up with one myself as I'm not familiar enough with the repository nor it's underlying architecture/internal workings.

It's not a breaking change at the very least as it's simply an addition to the public API surface. Maybe it affects trimmability though?

Author:	ErisApps
Assignees:	-
Labels:	api-suggestion, area-System.Text.Json, untriaged
Milestone:	-

[eiriktsarpalis]

Why would you need to have access to the JsonContent<TBody>? Wouldn't the JsonContent.Create method cover your use case?

[ErisApps]

JsonContent.Create doesn't have an overload that accepts a JsonTypeInfo<T> as far as I know. Other than that, in regard to trimming, said method would result in trim warnings as it is annotated with [RequiresUnreferencedCode(HttpContentJsonExtensions.SerializationUnreferencedCodeMessage)]

[eiriktsarpalis]

Right, so would JsonContent.Create overload for sourcegen not suffice to cover the use case described here?

[ErisApps]

I honestly didn't think of that myself when I raised this API proposal, but yeah, that would be sufficient for me.

[eiriktsarpalis]

Great, would it be possible to update the title and OP of the issue so that it reflects this?

[ghost]

This issue has been marked with the api-needs-work label. This may suggest that the proposal requires further refinement before it can be considered for API review. Please refer to our API review guidelines for a detailed description of the process.

When ready to submit an amended proposal, please ensure that the original post in this issue has been updated, following the API proposal template and examples as provided in the guidelines.

[ErisApps]

Will do so later today.

[eiriktsarpalis]

Seems to be a duplicate of #51544.