struct parser

gistfile1.rs

#![feature(default_type_params)]

extern crate iron;
extern crate serialize;
extern crate plugin;

use iron::Request;
use iron::typemap::Assoc;

use plugin::{PluginFor, Phantom};

use serialize::{json, Decodable};

#[deriving(Clone)]
pub struct StructParser<T>;

impl<T: 'static> Assoc<T> for StructParser<T> {}

impl<T> PluginFor<Request, T> for StructParser<T> {
    fn eval(req: &Request, _: Phantom<StructParser<T>>) -> Option<T> {
        if !req.body.is_empty() {
            let json_object = match json::from_str(req.body.as_slice()).ok() {
                Some(json_object) => json_object,
                None => {return None;},
            };
            let mut decoder = json::Decoder::new(json_object);
            match Decodable::decode(&mut decoder) {
                Ok(t) => Some(t),
                Err(err) => None,
            }
        } else {
            None
        }
    }
}

/*
lib.rs:27:19: 27:36 error: the trait `serialize::serialize::Decodable<serialize::json::Decoder,serialize::json::DecoderError>` is not implemented for the type `T`
lib.rs:27             match Decodable::decode(&mut decoder) {
                            ^~~~~~~~~~~~~~~~~
lib.rs:27:19: 27:36 note: the trait `serialize::serialize::Decodable` must be implemented because it is required by `serialize::serialize::Decodable::decode`
lib.rs:27             match Decodable::decode(&mut decoder) {
                            ^~~~~~~~~~~~~~~~~
error: aborting due to previous error
*/