使用 reqwest 在 Rust 中动态接收 json 数据

Question

我一直在尝试使用 reqwest 和 serde 接收 json 数据，但我一直收到错误消息：

Error: reqwest::Error { kind: Decode, source: Error("expected value", line: 1, column: 1) }

到目前为止，这是我的代码：

#[tokio::main]
async fn main() -> Result<(), Box<dyn std::error::Error>> {
    let url: String = String::from("https://api.slothpixel.me/api/players/leastrio");
    let echo_json: serde_json::Value = reqwest::Client::new()
        .get(url)
        .send()
        .await?
        .json()
        .await?;
    
    println!("{:#?}", echo_json);
    Ok(())
}

reqwest = { version = "0.11", features = ["json"] }
tokio = { version = "1", features = ["full"] }
serde_json = "1"

Answer 1

它应该可以快速测试：

tracing = "0.1"
tracing-subscriber = "0.2"

添加到主要：

let subscriber = tracing_subscriber::FmtSubscriber::builder()
    .with_max_level(tracing::Level::TRACE)
    .finish();

tracing::subscriber::set_global_default(subscriber)
    .expect("setting default subscriber failed");

dbg!(reqwest::Client::new().get(&url).send().await?.text().await);

RUST_LOG=trace cargo run

Jul 13 09:45:59.232 TRACE hyper::client::pool: checkout waiting for idle connection: ("https", api.slothpixel.me)
Jul 13 09:45:59.234 TRACE hyper::client::connect::http: Http::connect; scheme=Some("https"), host=Some("api.slothpixel.me"), port=None
Jul 13 09:45:59.234 DEBUG hyper::client::connect::dns: resolving host="api.slothpixel.me"
Jul 13 09:45:59.277 DEBUG hyper::client::connect::http: connecting to [2606:4700:3036::6815:5b3]:443
Jul 13 09:45:59.301 DEBUG hyper::client::connect::http: connected to [2606:4700:3036::6815:5b3]:443
Jul 13 09:45:59.352 TRACE hyper::client::conn: client handshake Http1
Jul 13 09:45:59.353 TRACE hyper::client::client: handshake complete, spawning background dispatcher task
Jul 13 09:45:59.353 TRACE hyper::proto::h1::conn: flushed({role=client}): State { reading: Init, writing: Init, keep_alive: Busy }
Jul 13 09:45:59.353 TRACE hyper::client::pool: checkout dropped for ("https", api.slothpixel.me)
Jul 13 09:45:59.354 TRACE encode_headers: hyper::proto::h1::role: Client::encode method=GET, body=None
Jul 13 09:45:59.355 DEBUG hyper::proto::h1::io: flushed 76 bytes
Jul 13 09:45:59.355 TRACE hyper::proto::h1::conn: flushed({role=client}): State { reading: Init, writing: KeepAlive, keep_alive: Busy }
Jul 13 09:45:59.376 TRACE hyper::proto::h1::conn: Conn::read_head
Jul 13 09:45:59.377 TRACE parse_headers: hyper::proto::h1::role: Response.parse([Header; 100], [u8; 953])
Jul 13 09:45:59.377 TRACE parse_headers: hyper::proto::h1::role: Response.parse Complete(937)
Jul 13 09:45:59.378 DEBUG hyper::proto::h1::io: parsed 14 headers
Jul 13 09:45:59.378 DEBUG hyper::proto::h1::conn: incoming body is content-length (16 bytes)
Jul 13 09:45:59.378 TRACE hyper::proto::h1::decode: decode; state=Length(16)
Jul 13 09:45:59.379 DEBUG hyper::proto::h1::conn: incoming body completed
Jul 13 09:45:59.379 TRACE hyper::proto::h1::conn: maybe_notify; read_from_io blocked
Jul 13 09:45:59.379 TRACE hyper::proto::h1::conn: flushed({role=client}): State { reading: Init, writing: Init, keep_alive: Idle }
Jul 13 09:45:59.379 TRACE hyper::proto::h1::conn: flushed({role=client}): State { reading: Init, writing: Init, keep_alive: Idle }
Jul 13 09:45:59.380 TRACE hyper::client::pool: put; add idle connection for ("https", api.slothpixel.me)
Jul 13 09:45:59.380 DEBUG hyper::client::pool: pooling idle connection for ("https", api.slothpixel.me)
[Jul 13 09:45:59.380 TRACE hyper::proto::h1::conn: flushed({role=client}): State { reading: Init, writing: Init, keep_alive: Idle }
src\main.rs:12] reqwest::Client::new().get(&url).send().await?.text().await = Ok(
    "error code: 1020",
)
Jul 13 09:45:59.381 TRACE hyper::proto::h1::dispatch: client tx closed
Jul 13 09:45:59.381 TRACE hyper::client::pool: pool closed, canceling idle interval
Jul 13 09:45:59.382 TRACE hyper::client::pool: checkout waiting for idle connection: ("https", api.slothpixel.me)
Jul 13 09:45:59.382 TRACE hyper::proto::h1::conn: State::close_read()
Jul 13 09:45:59.382 TRACE hyper::client::connect::http: Http::connect; scheme=Some("https"), host=Some("api.slothpixel.me"), port=None
Jul 13 09:45:59.382 TRACE hyper::proto::h1::conn: State::close_write()
Jul 13 09:45:59.382 DEBUG hyper::client::connect::dns: resolving host="api.slothpixel.me"
Jul 13 09:45:59.383 TRACE hyper::proto::h1::conn: flushed({role=client}): State { reading: Closed, writing: Closed, keep_alive: Disabled }
Jul 13 09:45:59.383 DEBUG hyper::client::connect::http: connecting to [2606:4700:3036::6815:5b3]:443
Jul 13 09:45:59.383 TRACE hyper::proto::h1::conn: shut down IO complete
Jul 13 09:45:59.396 DEBUG hyper::client::connect::http: connected to [2606:4700:3036::6815:5b3]:443
Jul 13 09:45:59.428 TRACE hyper::client::conn: client handshake Http1
Jul 13 09:45:59.428 TRACE hyper::client::client: handshake complete, spawning background dispatcher task
Jul 13 09:45:59.429 TRACE hyper::proto::h1::conn: flushed({role=client}): State { reading: Init, writing: Init, keep_alive: Busy }
Jul 13 09:45:59.429 TRACE hyper::client::pool: checkout dropped for ("https", api.slothpixel.me)
Jul 13 09:45:59.430 TRACE encode_headers: hyper::proto::h1::role: Client::encode method=GET, body=None
Jul 13 09:45:59.430 DEBUG hyper::proto::h1::io: flushed 76 bytes
Jul 13 09:45:59.430 TRACE hyper::proto::h1::conn: flushed({role=client}): State { reading: Init, writing: KeepAlive, keep_alive: Busy }
Jul 13 09:45:59.451 TRACE hyper::proto::h1::conn: Conn::read_head
Jul 13 09:45:59.451 TRACE parse_headers: hyper::proto::h1::role: Response.parse([Header; 100], [u8; 953])
Jul 13 09:45:59.452 TRACE parse_headers: hyper::proto::h1::role: Response.parse Complete(937)
Jul 13 09:45:59.452 DEBUG hyper::proto::h1::io: parsed 14 headers
Jul 13 09:45:59.452 DEBUG hyper::proto::h1::conn: incoming body is content-length (16 bytes)
Jul 13 09:45:59.453 TRACE hyper::proto::h1::decode: decode; state=Length(16)
Jul 13 09:45:59.453 DEBUG hyper::proto::h1::conn: incoming body completed
Jul 13 09:45:59.453 TRACE hyper::proto::h1::conn: maybe_notify; read_from_io blocked
Jul 13 09:45:59.453 TRACE hyper::proto::h1::conn: flushed({role=client}): State { reading: Init, writing: Init, keep_alive: Idle }
Jul 13 09:45:59.454 TRACE hyper::proto::h1::conn: flushed({role=client}): State { reading: Init, writing: Init, keep_alive: Idle }
Jul 13 09:45:59.454 TRACE hyper::client::pool: put; add idle connection for ("https", api.slothpixel.me)
Jul 13 09:45:59.454 DEBUG hyper::client::pool: pooling idle connection for ("https", api.slothpixel.me)
Jul 13 09:45:59.454 TRACE hyper::proto::h1::conn: flushed({role=client}): State { reading: Init, writing: Init, keep_alive: Idle }
Jul 13 09:45:59.454 TRACE hyper::client::pool: pool closed, canceling idle interval
Jul 13 09:45:59.454 TRACE hyper::proto::h1::dispatch: client tx closed
Jul 13 09:45:59.455 TRACE hyper::proto::h1::conn: State::close_read()
Jul 13 09:45:59.455 TRACE hyper::proto::h1::conn: State::close_write()
Jul 13 09:45:59.455 TRACE hyper::proto::h1::conn: flushed({role=client}): State { reading: Closed, writing: Closed, keep_alive: Disabled }
Jul 13 09:45:59.456 TRACE hyper::proto::h1::conn: shut down IO complete
Error: reqwest::Error { kind: Decode, source: Error("expected value", line: 1, column: 1) }

error code: 1020 甚至没有 json 对象与 https://api.slothpixel.me/api/players/ that return a json object "error", I suggest a bug report this to https://github.com/slothpixel/core 或它足够的地方导致此错误很奇怪。

Answer 2

所以我尝试了一些东西，看来您需要添加用户代理才能正常工作。不知道为什么文档没有提到它。我猜 reqwest 默认情况下没有提供。

reqwest::Client::new()
        .get(url)
        .header("User-Agent", "Reqwest Rust Test")
        .send()
        .await?
        .json()
        .await?;

我用过这个，效果很好！

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