Fastify adapter: Custom content-type parser for application/json is breaking normal REST api requests on a fastify server

https://github.com/trpc/trpc/blob/d5808b863490f95ff76defce4886833b11672e88/packages/server/src/adapters/fastify/fastifyTRPCPlugin.ts#L25-L31

This works just fine for tRPC endpoints but breaks other REST api endpoints as request.body is a string where it’s expected to an object. This can be easily reproduced on the official fastify examples by creating a REST POST endpoint and sending some data inside body.

[soulsam480]

Yes exactly. I think if we can match the fastify-plugin type, we don’t need to encapsulate it and can use it directly. Thanks for the quick fix.

[skarab42]

@soulsam480 I found the problem, I am working on a fix…

Reading the docs:

As with the other APIs, addContentTypeParser is encapsulated in the scope in which it is declared. This means that if you declare it in the root scope it will be available everywhere, while if you declare it inside a plugin it will be available only in that scope and its children.

I probably broke the encapsulation system with the use of fastify-plugin, I’m reworking the plugin to allow its use with or without fastify-plugin.