search

datamapper / dm-serializer

DataMapper plugin for serializing Resources and Collections
http://datamapper.org/
MIT License
40 stars 44 forks source link

Overriding to_json in a class causes associated objects to over-quote and over-escape #16

Open solnic opened 13 years ago

solnic commented 13 years ago

Any suggestions for a clearer title for this ticket would be very much appreciated ;)

If you override to_json in a class Foo, and class Bar has n foos, calling @bar.foos.to_json in an instance of Bar will emit bad JSON which has too many quotes and backslash escapes.

I created a toy project that demonstrates this at http://github.com/xxx/dm10-association_to_json .

Maybe there's just a different way to do this now.

Created by mpd - 2009-10-03 19:06:22 UTC

Original Lighthouse ticket: http://datamapper.lighthouseapp.com/projects/20609/tickets/1075

solnic commented 13 years ago

I did notice

def to_json(*args) res = super p res.class # Hash? res end

super is returning a hash, but that isn’t valid JSON.

What is the correct way to do this now?

by mpd

solnic commented 13 years ago

@namelessjon: assigning this to you because (I think?) you recently did some work on to_json in dm-serializer.

by Dan Kubb (dkubb)

solnic commented 13 years ago

Okay, I know why this is happening. It’s due to the changes I made to speed things up, which has the side effect of slightly breaking the assumptions the JSON library is making. I will try and work out how to safely allow overriding while keeping the speedup for users who arn’t doing this.

As a temporary measure, what are you trying to accomplish with the custom method? It may be possible to duplicate that through options to the to_json call.

by Jonathan Stott (namelessjon)

solnic commented 13 years ago

I’m aggregating a bunch of method return values from an associated object (and those methods are not known until runtime, so the associated object is queried both for the methods to include and the results.)

I could get around it by delegating methods or using method_missing. I’m not terribly keen on doing either for this sort of operation, though.

by mpd

solnic commented 13 years ago

You can work around it by calling to_a on the collection before to_json. So in the above example, @bar.foos.to_a.to_json should work fine.

by Dane Jensen

solnic commented 13 years ago

Any progress on this issue?

by Dan Kubb (dkubb)

solnic commented 13 years ago

As I see it, there are basically two options:

  1. Revert the original patch and go back to manually constructing JSON.
  2. Do as AMo do, and have a @as_hash@ (or method with that intent, at least) and a @to_json@. It would then be possible to override @as_hash@ however you liked, and @to_json@ would just call @as_hash.to_json@.

Also, the @to_json@ method in the example could check to see if @args@ is a hash, and if it has the @:to_json@ option set to false, and if so, just return a hash.

by Jonathan Stott (namelessjon)

gilbert commented 12 years ago

Any progress on this issue?

solnic commented 12 years ago

No. Not really. Happy to accept pull requests though :)