Parse environment variables in serde crate using deserialize_with
MIT License
Parse environment variables in serde
crate using deserialize_with
.
use std::env;
use serde_json;
use serde::Deserialize;
use serde_with_expand_env::with_expand_envs;
#[derive(Deserialize, Debug)]
struct Test {
#[serde(deserialize_with="with_expand_envs")]
number: usize,
#[serde(deserialize_with="with_expand_envs")]
string: String,
#[serde(deserialize_with="with_expand_envs")]
default: usize,
}
fn main() {
let serialized = r#"{"number": "$NUMBER",
"string": "my string: $STRING",
"default": "${DEFAULT:-42}"
}"#;
// No envs set will fail with enviroment variable not found
assert_eq!(serde_json::from_str::<Test>(&serialized).is_err(), true);
env::set_var("NUMBER", "42");
env::set_var("STRING", "hacker");
let deserialized: Test = serde_json::from_str(&serialized).unwrap();
assert_eq!(deserialized.number, 42);
assert_eq!(deserialized.string, "my string: hacker");
assert_eq!(deserialized.default, 42);
env::set_var("DEFAULT", "4200");
let deserialized: Test = serde_json::from_str(&serialized).unwrap();
assert_eq!(deserialized.default, 4200);
// Invalid number
env::set_var("NUMBER", "cuarentaydos");
env::set_var("STRING", "42");
assert_eq!(serde_json::from_str::<Test>(&serialized).is_err(), true);
}
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