How to automatically log responses using Flurl v3.0.0 - flurl

Question

I'm using Flurl in integration testing and trying to configure a client to log responses (using Flurl.Http 3.0.0).
I'm using event handlers to read the response as a string and then log it.
However, if the calling code uses IFlurlResponse.GetJsonAsync<> when the logging is enabled, the deserialized object is null (I imagine because the stream has already been read).
I thought it may be possible because I can see that internally Flurl tracks whether the response stream has been read (using the _streamRead and _capturedBody members).
Here's a repro, using Flurl.Http 3.0.0:
class Program
{
static async Task Main(string[] args)
{
using (var client = new FlurlClient("https://jsonplaceholder.typicode.com/"))
{
var post = await client
.Request("posts/1")
.ConfigureRequest(settings => settings.AfterCallAsync = LogResponse)
.GetJsonAsync<Post>();
Console.WriteLine($"Is null with logging enabled: {post is null}"); // prints True
post = await client.Request("posts/1").GetJsonAsync<Post>();
Console.WriteLine($"Is null with logging disabled: {post is null}"); // prints False
}
}
private static async Task LogResponse(FlurlCall call)
{
var responseString = await call.Response.GetStringAsync();
Console.WriteLine(responseString);
}
}
public class Post
{
public int Id { get; set; }
public int UserId { get; set; }
public string Title { get; set; }
public string Body { get; set; }
}
Output:
{
"userId": 1,
"id": 1,
"title": "sunt aut facere repellat provident occaecati excepturi optio reprehenderit",
"body": "quia et suscipit\nsuscipit recusandae consequuntur expedita et cum\nreprehenderit molestiae ut ut quas totam\nnostrum rerum est autem sunt rem eveniet architecto"
}
Is null with logging enabled: True
Is null with logging disabled: False
If I change the calling code from using GetJsonAsync<> to GetStringAsync and handle json deserialization myself then the response can be 'read' twice, but it's more verbose.

Answer 1

UPDATE: The fix has been released.
You're correct that in most cases Flurl "captures" deserialized responses so they can easily be read multiple times. But, as I think you came close to concluding, this currently only works when you're deserializing to the same type. If both the event handler and main logic were deserializing to a string, or both to a Post, this should work.
I'm not sure if I'd quite call this a bug (maybe?), but I'm definitely convinced that getting it to work as you're expecting here would be a nice enhancement and not too hard. Please open an issue and I'll look at getting this done in a future release.