Serialise complex objects correctly

[laurence79]

This is essentially a reimplementation of the ResourceSerializer that copes with a couple of edge cases that have tripped me up in my own use:

• Circular references
• Inclusion of deeply nested objects

Take a look at ResourceGraphSerializerTests to see tests that pass with the new serialiser. The new serialiser also passes all the existing tests (with a couple of exceptions where I have overridden the existing test with comments as to why).

The new serialiser approach differs from the original by first building a graph of objects to serialise using the IncludingContext, and then generates the response JSON from that.

This is anecdotal but I've also seen modest performance improvements from this approach.

By default the original serialiser is still used unless a new configuration option is set config.ConfigureJsonApi(new JsonApiConfiguration { UseGraphSerializer = true });

I appreciate this is a large change, but hopefully it will be a benefit to the project 😊

[joukevandermaas]

This sounds great, I'll try to make some time to review this soon. Thanks so much!

[laurence79]

Thanks @joukevandermaas

[laurence79]

Fixes #141 (when using the graph serialiser)

[bjornharrtell]

Seems like nice work @laurence79, looking forward to testing it. I wonder if it also resolves https://github.com/joukevandermaas/saule/issues/99?

[laurence79]

Thanks @bjornharrtell, yes it seems like it might because only the attributes and relationships declared in the resource are read from the target objects.

[laurence79]

AppVeyor had a timeout on package restore. I couldn't see a way to easily retry the build, so I bumped the Newtonsoft.Json version to 10.0.2, hope thats ok 😊

[laurence79]

Ok @joukevandermaas, I think this is ready to be reviewed again 😊

[joukevandermaas]

@laurence79 Thanks a lot for this! I published a new pre-release with these changes in it.