Add #[serde(default)] to the every field of struct.
There is no need adding manually #[serde(default)] to fields of struct when deserializing a json string missing some fields.
use serde_default::serde_default;
use serde::{Deserialize, Serialize};
#[serde_default] // this needs to be above of #[derive(Serialize...)]
#[derive(Deserialize, Serialize)]
Struct Foo {
name: String,
age: int,
#[serde(alias = "foobar", default)]
bar: String,
}The result that the macro expanded is:
#[derive(Deserialize, Serialize)]
struct Foo {
#[serde(default)]
name: String,
#[serde(default)]
age: usize,
#[serde(alias = "foobar", default)]
bar: String,
}usage:
fn main() {
let john = json!({"name": "lyf"});
let p: Foo = serde_json::from_str(&john.to_string()).unwrap();
}
// the program would not panic because of missing field `age`.Cargo.toml:
...
[dependencies]
serde_default = {git = "https://github.com/ctaoist/serde_default"}
serde = { version = "*", features = ["derive"] }