预期的struct`vec'，找到了枚举``

发布于 2025-01-23 21:59:02 字数 977 浏览 0 评论 0 原文

我发现很难理解以下代码有什么问题。我得到了预期的struct VEC，找到枚举结果 ok ok（from_cache）的错误，但是我已经从

在网络刮擦期间，我正在尝试缓存缓存中URL的内容，并试图重新使用它。

use std::error::Error;

#[tokio::main]
async fn main() ->  Result<(), Box<dyn Error>> {
    let url: &str = "https://example.com/";
    let html = match cacache::read("./cache", url).await? {
        Ok(from_cache) => String::from_utf8(from_cache),
        Err(_) => {
            let t_html = reqwest::get(url).await?.text().await?;
            cacache::write("./cache", url, &t_html).await?;
            t_html
        },
    };
    println!("html = {:?}", html);

    Ok(())
}

这是

原文

I find it difficult to understand what's wrong with the below code. I'm getting expected struct Vec, found enum Result error at Ok(from_cache), but I have adopted the code from https://github.com/platy/update-tracker/blob/843092708906063704442f352231bfbac5b06196/server/src/web/mod.rs#L216-L226

During web scraping, I'm trying to cache the content of the URL in the cache and trying to reuse it.

use std::error::Error;

#[tokio::main]
async fn main() ->  Result<(), Box<dyn Error>> {
    let url: &str = "https://example.com/";
    let html = match cacache::read("./cache", url).await? {
        Ok(from_cache) => String::from_utf8(from_cache),
        Err(_) => {
            let t_html = reqwest::get(url).await?.text().await?;
            cacache::write("./cache", url, &t_html).await?;
            t_html
        },
    };
    println!("html = {:?}", html);

    Ok(())
}

Here's the playground (but, it shows other errors due to missing dependencies). Can anyone please explain this or share any relevant guide to gather more information about this topic?

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囚你心 2025-01-30 21:59:02

回想一下 ？操作员通过传播 err < 结果（或 option ） /code>（或无）从当前功能出发。因此，此表达式：

cacache::read("./cache", url).await?

具有类型 vec＆lt; u8＆gt; 作为？操作员已解开结果。如果要自己处理错误，请省略？操作员：

cacache::read("./cache", url).await

Recall that the ? operator unwraps a Result (or Option) by propagating the Err (or None) case out of the current function. Therefore, this expression: