Selecting MessageBodyWriter seems to ignore priority given a specific type match
by Steven Schlansker
Hi Resteasy users, [ apologies for the re-post, sent from wrong email the first time ]
I'm a happy user of Resteasy + Jackson for Json processing.
Recently, I had the misfortune of attempting to serialize a basic String:
client.post(Entity.json("Test"));
if you call Jackson directly, it does the right thing:
mapper.writeValueAsString("Test") => "\"Test\""
However, much to my surprise, when sending it via JAX-RS client, it is written as a bare word without quotes -- and is rejected server-side.
After some debugging, I realized that both StringTextStar and JacksonJsonProvider were ending up with Priorities.USER and being seen as equivalent.
No good! So I changed my registration:
context.register(new JacksonJsonProvider(myMapper), Integer.MAX_VALUE);
I then proceeded to triumphantly ... observe the same test failure as before!
Dug quite a bit further in, and it seems that the selection process in MediaTypeMap$TypedEntryComparator
has the unfortunate property that it will select (via compareTypes) a *less priority* MessageBodyWriter if the type is a tighter bound on the Entity.
So in my case, I get
StringTextStar -> String.class@5000
JacksonJsonProvider -> Object.class(a)Integer.MAX_VALUE
and the TypedEntryComparator selects StringTextStar since String is-assignable to Object, despite my attempt at an ultimate priority registration.
How do I fix this? Preferably without removing StringTextStar entirely, as I'm sure that will break something else (reading error messages perhaps).
Thanks for any advice,
Steven
4 years, 5 months