Function prefixed

pub fn prefixed(prefix: &str) -> Prefixed<'_>

Instantiates Prefixed from which values can be both serialized and deserialized with a prefix.

The prefix is added to all keys during serialization and is expected to be present during deserialization. This is useful for namespacing environment variables to avoid conflicts.

Examples

Serializing with a prefix

use serde::{Serialize};
use serde_envfile::{prefixed, Error};

#[derive(Serialize)]
struct Config {
    database_url: String,
    port: u16,
}

fn main() -> Result<(), Error> {
    let config = Config {
        database_url: "postgres://localhost/mydb".to_string(),
        port: 8080,
    };

    // Serialize with "APP_" prefix
    let env_string = prefixed("APP_").to_string(&config)?;
    // Results in: APP_DATABASE_URL="postgres://localhost/mydb"\nAPP_PORT="8080"

    println!("{}", env_string);
    Ok(())
}

Deserializing with a prefix

use serde::{Deserialize};
use serde_envfile::{prefixed, Error};

#[derive(Deserialize, Debug)]
struct Config {
    database_url: String,
    port: u16,
}

fn main() -> Result<(), Error> {
    let env_string = "APP_DATABASE_URL=\"postgres://localhost/mydb\"\nAPP_PORT=\"8080\"";

    // Deserialize with "APP_" prefix
    let config: Config = prefixed("APP_").from_str(env_string)?;

    assert_eq!(config.database_url, "postgres://localhost/mydb");
    assert_eq!(config.port, 8080);
     
    Ok(())
}