Code shared from the Rust Playground

playground.rs

#![feature(result_map_or_else)]

extern crate serde; // 1.0.84
extern crate serde_derive; // 1.0.84
extern crate serde_json; // 1.0.34

use serde::Serialize;

#[derive(Debug, Serialize)]
#[serde(tag = "status", content = "result")]
enum MyJsonResult<T, E>
where
    T: Serialize,
    E: Serialize,
{
    Success(T),
    Error(E),
}

#[derive(Debug, Serialize)]
struct Post {
    pub author: String,
    pub content: String,
}

#[derive(Debug, Serialize)]
enum JsonStatus {
    Success,
    Error,
}

fn main() {
    let result: Result<Vec<Post>, &'static str> = Ok(vec![Post {
        author: "fuck".to_string(),
        content: "you".to_string(),
    }]);
    let result = result.map_or_else(
        |item| MyJsonResult::Error(item),
        |item| MyJsonResult::Success(item),
    );
    println!("{}", serde_json::to_string_pretty(&result).unwrap());
    let result: Result<Vec<Post>, &'static str> = Err("posts not found");
    let result = result.map_or_else(
        |item| MyJsonResult::Error(item),
        |item| MyJsonResult::Success(item),
    );
    println!("{}", serde_json::to_string_pretty(&result).unwrap());
}

Serde serialize structure like:

{
  "status": "Success",
  "result": [
    {
      "author": "fuck",
      "content": "you"
    }
  ]
}

or

{
  "status": "Error",
  "result": "posts not found"
}