Replace successful.ok with json

[isaacabraham]

If you go to the Saturn endpoint directly with a browser that doesn't specify the content type as JSON, Giraffe falls back to using the XML serializer by default. This requires [<AllowCLIMutable>] attributes on all types, and without this you get a confusing error saying that your types requires a non-default constructor or something. This is very confusing for a beginner.

To work around this, we can either explain this in the docs (a good thing to do anyway), but it might also be worth replacing Successful.OK with json in Saturn / Giraffe.

[theimowski]

Can you elaborate on how to reproduce this behaviour? Do you need to trick the browser somehow or is it due to using older browsers?

[isaacabraham]

You can test this out with Firefox, for example - it doesn't explicitly send the preferred content type as JSON.

[theimowski]

With the default template? Works ok for me on Firefox 63.0.3 (64-bit) for OSX:

[isaacabraham]

Weird - must be my firefox then. Let me double check!

[isaacabraham]

I assume that that request you have highlighted is from you entering that URI in the browser directly (and not just loading the SAFE web app)?

[theimowski]

Ah ok now I got you - I went indirectly via http://localhost:8080/
The outlined issue does occur if I go to http://localhost:8080/api/init in firefox

So the Giraffe.Serialization.Json.IJsonSerializer comes into action only if request contains json content-type right? If so the simplest change indeed seems to be changing Successful.OK to json

[isaacabraham]

Exactly :-)