Question, C# generated client: Is there a way to stream large json's?

[byte3]

I want to send a large json through a nswag generated csharp client.

My problem is with the generated code:

var json_ = Newtonsoft.Json.JsonConvert.SerializeObject(model, _settings.Value);
var content_ = new System.Net.Http.StringContent(json_);

Serializing model into a json string essentialy doubles the memory consumption.

I would like to serialze the json into a stream and use StreamContent instead of StringContent.
Like it is explained here: https://johnthiriet.com/efficient-post-calls/

Is there a way to generate a client that way?
By looking at the source code it does not seem possible. But maybe is missed something.

[dittodhole]

I have the same question, since I migrated one of our clients to a swagger definition and generating the client with NSwag - actually, one API even has a bulk-insert endpoint (there could be additional optimization done on providing the stream in chunks).

I've actually found an interesting part here (operation.HasBinaryBodyParameter):

NSwag/src/NSwag.CodeGeneration.CSharp/Templates/Client.Class.liquid

Lines 197 to 204 in 13de8d0

	{% if operation.HasBinaryBodyParameter -%}
	{% if operation.ContentParameter.HasBinaryBodyWithMultipleMimeTypes -%}
	var content_ = new System.Net.Http.StreamContent({{ operation.ContentParameter.VariableName }}.Data);
	content_.Headers.ContentType = System.Net.Http.Headers.MediaTypeHeaderValue.Parse({{ operation.ContentParameter.VariableName }}.ContentType);
	{% else -%}
	var content_ = new System.Net.Http.StreamContent({{ operation.ContentParameter.VariableName }});
	content_.Headers.ContentType = System.Net.Http.Headers.MediaTypeHeaderValue.Parse("{{ operation.Consumes }}");
	{% endif -%}

The default branch is this here:

NSwag/src/NSwag.CodeGeneration.CSharp/Templates/Client.Class.liquid

Lines 216 to 219 in 13de8d0

	{% else -%}
	var json_ = {% if UseSystemTextJson %}System.Text.Json.JsonSerializer.Serialize{% else %}Newtonsoft.Json.JsonConvert.SerializeObject{% endif %}({{ operation.ContentParameter.VariableName }}, {% if SerializeTypeInformation %}typeof({{ operation.ContentParameter.Type }}), {% endif %}{% if UseRequestAndResponseSerializationSettings %}_requestSettings{% else %}_settings{% endif %}.Value);
	var content_ = new System.Net.Http.StringContent(json_);
	content_.Headers.ContentType = System.Net.Http.Headers.MediaTypeHeaderValue.Parse("{{ operation.Consumes }}");

But could also be this here (operation.HasPlainTextBodyParameter):

NSwag/src/NSwag.CodeGeneration.CSharp/Templates/Client.Class.liquid

Lines 213 to 215 in 13de8d0

	{% elsif operation.HasPlainTextBodyParameter -%}
	var content_ = new System.Net.Http.StringContent({{ operation.ContentParameter.VariableName }});
	content_.Headers.ContentType = System.Net.Http.Headers.MediaTypeHeaderValue.Parse("{{ operation.Consumes }}");

Some idea how to declare the operation body binary somehow?

Best

[gklittlejohn]

I managed to do this by using a custom Client.Class.liquid template (setting templateDirectory in the .nswag) and using a custom content that writes to the request stream directly. Obviously this is not idea using a custom template.

System.Net.Http.Json looks like it takes this same approach but I'm not sure if there are any issues with this.