Rust の http クライアントの使い方 (Post)

次のページを参考にしました。
Crate reqwest

プロジェクトの作成

cargo new http_post --bin

Cargo.toml

[package]
name = "http_post"
version = "0.1.0"
edition = "2024"

#

[dependencies]
tokio = { version = "1", features = ["full"] }
reqwest = { version = "0.12", features = ["json"] }
serde_json = "1.0"

src/main.rs

// --------------------------------------------------------------------
/*
	http_post.rs

					Jul/15/2020
*/
// --------------------------------------------------------------------
use std::collections::HashMap;

# [tokio::main]

async fn main() -> Result<(), Box<dyn std::error::Error>> {
	eprintln!("*** 開始 ***");
	let mut map = HashMap::new();
	map.insert("user", "jiro");
	map.insert("password", "123456");

	let client = reqwest::Client::new();
	let url = "https://httpbin.org/post";
	let resp = client.post(url)
		.json(&map)
		.send()
		.await?;

//	println!("{:#?}", resp);

	let body = resp.text().await? ;
//	println!("{:#?}", body);

	let json: serde_json::Value = serde_json::from_str(&body)?;

	let obj = json.as_object().unwrap();

	for (key,value) in obj.iter() {
		println!("{}\t{}",key,value);
		}

	eprintln!("*** 終了 ***");
	Ok(())
}

// --------------------------------------------------------------------

コンパイル

cargo build

実行結果

$ cargo run
    Finished `dev` profile [unoptimized + debuginfo] target(s) in 0.09s
     Running `target/debug/http_post`
*** 開始 ***
args	{}
data	"{\"user\":\"jiro\",\"password\":\"123456\"}"
files	{}
form	{}
headers	{"Accept":"*/*","Content-Length":"35","Content-Type":"application/json","Host":"httpbin.org","X-Amzn-Trace-Id":"Root=1-691d6ca9-574a76b660ffe4151fdb70f5"}
json	{"password":"123456","user":"jiro"}
origin	"219.126.140.210"
url	"https://httpbin.org/post"
*** 終了 ***

確認したバージョン

$ rustc --version
rustc 1.91.1 (ed61e7d7e 2025-11-07) (Arch Linux rust 1:1.91.1-2)

$ cargo --version
cargo 1.91.1 (ea2d97820 2025-10-10) (Arch Linux rust 1:1.91.1-2)