get_bucket_mirror_back 接口用于获取 Bucket 的回源规则，本文介绍如何通过 Rust SDK 的 get_bucket_mirror_back 接口读取已配置的镜像或重定向回源策略。

注意事项

您需要根据实际情况，填写示例代码中的地域和访问域名，详细介绍，请参见地域和访问域名。

为了防止密钥泄露，本文示例代码需要从环境变量中读取 Access Key ID 和 Secret Access Key。因此使用 SDK 前，您需要配置长期访问凭证，详细介绍，请参见配置长期访问凭证。

分层桶不支持调用 get_bucket_mirror_back。

仅当下载请求返回 404 时，回源条件才会生效。

回源地址最多配置 5 个，单地址长度不超过 255 个字符。

透传 Host、Content-Length、Date、Authorization 类型的 HTTP Header 会被自动过滤。

权限说明

火山引擎主账号默认拥有全部权限，但是 IAM 用户默认没有任何权限。如果您需要使用子账号执行 get_bucket_mirror_back 操作，火山引擎主账号需通过 IAM策略和桶策略为该子账号授予以下权限：

tos:GetBucketMirrorBack

代码示例

获取桶的回源规则

use async_trait::async_trait;​
use futures_core::future::BoxFuture;​
use std::env;​
use std::future::Future;​
use std::time::Duration;​
use tokio::runtime::Handle;​
use ve_tos_rust_sdk::common::init_tracing_log;​
use ve_tos_rust_sdk::asynchronous::bucket::BucketAPI;​
use ve_tos_rust_sdk::asynchronous::tos;​
use ve_tos_rust_sdk::asynchronous::tos::AsyncRuntime;​
use ve_tos_rust_sdk::bucket::{GetBucketMirrorBackInput};​
use ve_tos_rust_sdk::error::TosError;​
​
#[derive(Debug, Default)]​
pub struct TokioRuntime {}​
​
#[async_trait]​
impl AsyncRuntime for TokioRuntime {​
    type JoinError = tokio::task::JoinError;​
    async fn sleep(&self, duration: Duration) {​
        tokio::time::sleep(duration).await;​
    }​
​
    fn spawn<'a, F>(&self, future: F) -> BoxFuture<'a, Result<F::Output, Self::JoinError>>​
    where​
        F: Future + Send + 'static,​
        F::Output: Send + 'static,​
    {​
        Box::pin(Handle::current().spawn(future))​
    }​
​
    fn block_on<F: Future>(&self, future: F) -> F::Output {​
        Handle::current().block_on(future)​
    }​
}​
​
#[tokio::main]​
async fn main() {​
    let _guard = init_tracing_log("info", "temp/logs", "app.log");​
​
    let ak = env::var("TOS_ACCESS_KEY").unwrap_or("".to_string());​
    let sk = env::var("TOS_SECRET_KEY").unwrap_or("".to_string());​
    let endpoint = "https://tos-cn-beijing.volces.com";​
    let region = "cn-beijing";​
    let client = tos::builder::<TokioRuntime>()​
        .connection_timeout(3000)​
        .request_timeout(10000)​
        .max_retry_count(3)​
        .ak(ak)​
        .sk(sk)​
        .region(region)​
        .endpoint(endpoint)​
        .build().unwrap();​
​
    let bucket_name = "example-bucket";​
    let input = GetBucketMirrorBackInput::new(bucket_name);​
    let result = client.get_bucket_mirror_back(&input).await;​
​
    match result {​
        Ok(output) => {​
            println!("request_id: {}", output.request_id());​
            let rules = output.rules();​
            println!("Number of rules: {}", rules.len());​
            for (idx, rule) in rules.iter().enumerate() {​
                println!("\nRule [{}]:", idx);​
                println!("  ID: {}", rule.id());​
                let condition = rule.condition();​
                println!("  Condition:");​
                println!("    HttpCode: {}", condition.http_code());​
                println!("    KeyPrefix: {}", condition.key_prefix());​
                println!("    KeySuffix: {}", condition.key_suffix());​
                println!("    AllowHost: {:?}", condition.allow_host());​
                println!("    HttpMethod: {:?}", condition.http_method());​
                let redirect = rule.redirect();​
                println!("  Redirect:");​
                println!("    RedirectType: {}", redirect.redirect_type().as_str());​
                println!("    FetchSourceOnRedirect: {}", redirect.fetch_source_on_redirect());​
                println!("    PassQuery: {}", redirect.pass_query());​
                println!("    FollowRedirect: {}", redirect.follow_redirect());​
                if let Some(public_source) = redirect.public_source() {​
                    println!("    PublicSource:");​
                    let source_endpoint = public_source.source_endpoint();​
                    println!("      Primary Endpoints: {:?}", source_endpoint.primary());​
                }​
            }​
        }​
        Err(err) => {​
            match err {​
                TosError::TosClientError { message, .. } => {​
                    println!("Client error: {}", message);​
                }​
                TosError::TosServerError { request_id, ec, code, .. } => {​
                    println!("Server error: request_id={}, ec={}, code={}", request_id, ec, code);​
                }​
            }​
        }​
    }​
}​

对象存储