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use serde::{Deserialize, Serialize};
use serde_json::{json, Value};
// From the serde_json docs:
//
// > There are three common ways that you might find yourself needing to work with
// > JSON data in Rust.
// >
// > 1. As text data. An unprocessed string of JSON data that you receive on an
// > HTTP endpoint, read from a file, or prepare to send to a remote server.
// > 2. As an untyped or loosely typed representation. Maybe you want to check
// > that some JSON data is valid before passing it on, but without knowing
// > the structure of what it contains. Or you want to do very basic
// > manipulations like insert a key in a particular spot.
// > 3. As a strongly typed Rust data structure. When you expect all or most of
// > your data to conform to a particular structure and want to get real work
// > done without JSON’s loosey-goosey nature tripping you up.
//
// So let's take a look at all three...
////////////////////////////////////////////////////////////////////////////////
// Types
////////////////////////////////////////////////////////////////////////////////
#[derive(Serialize, Deserialize, Debug)]
struct Person {
fname: String,
lname: String,
age: u8,
}
////////////////////////////////////////////////////////////////////////////////
// Functions
////////////////////////////////////////////////////////////////////////////////
// 1) Reading/writing from/to plain text.
// TL;DR:
// - read: serde_json::from_str(data)
// - write: x.to_string()
fn one() {
let data = json!({
"fname": "William",
"lname": "Carroll",
"age": 30,
})
.to_string();
println!("result: {:?}", data);
}
// 2) Parse into a loosely typed representation; mutate it; serialize it back.
// TL;DR:
// - read: serde_json::from_str(data)
// - write: x.to_string()
fn two() {
let data = r#"{"fname":"William","lname":"Carroll","age":30}"#;
let mut parsed: Value = serde_json::from_str(data).unwrap();
parsed["fname"] = json!("Norm");
parsed["lname"] = json!("Macdonald");
parsed["age"] = json!(61);
let result = parsed.to_string();
println!("result: {:?}", result);
}
// 3) Parse into a strongly typed structure.
// TL;DR:
// - read: serde_json::from_str(data)
// - write: serde_json::to_string(x).unwrap()
fn three() {
let data = r#"{"fname":"William","lname":"Carroll","age":30}"#;
let mut read: Person = serde_json::from_str(data).unwrap();
read.fname = "Norm".to_string();
read.lname = "Macdonald".to_string();
read.age = 61;
let write = serde_json::to_string(&read).unwrap();
println!("result: {:?}", write);
}
////////////////////////////////////////////////////////////////////////////////
// Main
////////////////////////////////////////////////////////////////////////////////
fn main() {
three()
}
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