主页 / user-127508

Istvan's questions

Martin Hope
Istvan
Asked: 2024-11-09 18:25:46 +0800 CST
  • 6

我想要一个带有 Axum 的自定义响应类型，并将业务逻辑映射到 HTTP 响应，如下所示：

use axum::{
    http::StatusCode,
    response::{Html, IntoResponse},
    Json,
};
use serde::Serialize;

// Response

pub enum Response<T = ()> {
    Created,
    NoContent,
    JsonData(T),
    HtmlData(T),
}

impl<T> IntoResponse for Response<T>
where
    T: Serialize
{
    fn into_response(self) -> axum::response::Response {
        match self {
            Self::Created => StatusCode::CREATED.into_response(),
            Self::NoContent => StatusCode::OK.into_response(),
            Self::JsonData(data) => (StatusCode::OK, Json(data)).into_response(),
            Self::HtmlData(data) => (StatusCode::OK, Html(data)).into_response(),
        }
    }
}

然而，这并不管用。

no method named `into_response` found for tuple `(StatusCode, Html<T>)` in the current scope
method not found in `(StatusCode, Html<T>)

我想知道为什么不能像使用 Json 那样使用 Html。

http
Martin Hope
Istvan
Asked: 2024-01-16 04:29:11 +0800 CST
  • 5

我想获取路径的各个部分并删除它的第一部分和最后一部分。

例子：

a/b/c/d.txt -> b/c

我认为可以通过简单的列表操作来完成。但是我找不到更好的方法：

let mut comps: Vec<_> = content_file.components().skip(1).collect();
comps.reverse();
let mut ret: Vec<_> = comps.iter().skip(1).collect();
ret.reverse();

有更好的方法来实现这一目标吗？

rust
Martin Hope
Istvan
Asked: 2024-01-14 03:56:43 +0800 CST
  • 5

我试图了解借用检查器在递归函数调用情况下的工作原理：

fn visit_dirs_rec(dir: &Path, mut acc: Vec<PathBuf>) -> Result<Vec<PathBuf>, io::Error> {
    if dir.is_dir() {
        for entry in std::fs::read_dir(dir)? {
            let entry = entry?;
            let path = entry.path();
            if path.is_dir() {
                visit_dirs_rec(&path, &acc)?;
            } else if path.is_file() {
                acc.push(path)
            } else {
                error!("{:?}", path);
            }
        }
    }
    Ok(acc)
}

fn visit_dirs(dir: &Path) -> Result<Vec<PathBuf>, io::Error> {
    visit_dirs_rec(dir, vec![])
}

error[E0382]: use of moved value: `acc`
  --> src/main.rs:16:39
   |
10 | fn visit_dirs_rec(dir: &Path, mut acc: Vec<PathBuf>) -> Result<Vec<PathBuf>, io::Error> {
   |                               ------- move occurs because `acc` has type `Vec<PathBuf>`, which does not implement the `Copy` trait
11 |     if dir.is_dir() {
12 |         for entry in std::fs::read_dir(dir)? {
   |         ------------------------------------ inside of this loop
...
16 |                 visit_dirs_rec(&path, acc)?;
   |                                       ^^^ value moved here, in previous iteration of loop
   |
note: consider changing this parameter type in function `visit_dirs_rec` to borrow instead if owning the value isn't necessary
  --> src/main.rs:10:40
   |
10 | fn visit_dirs_rec(dir: &Path, mut acc: Vec<PathBuf>) -> Result<Vec<PathBuf>, io::Error> {
   |    -------------- in this function     ^^^^^^^^^^^^ this parameter takes ownership of the value
help: consider cloning the value if the performance cost is acceptable
   |
16 |                 visit_dirs_rec(&path, acc.clone())?;
   |                                          ++++++++

For more information about this error, try `rustc --explain E0382`.
warning: `api` (bin "api") generated 1 warning
error: could not compile `api` (bin "api") due to previous error; 1 warning emitted

有没有办法让借用检查员在没有 .clone 的情况下感到满意？

recursion