如何在Actix中显示自定义Tera错误？

Question

我正在研究rust/actix/tera，但不知道如何在actix输出中返回自定义的tera错误字符串。

下面是我的代码：

use actix_web::{App, get, error, Error, HttpResponse, HttpServer};
use tera::{Tera, Context};
use lazy_static::lazy_static;

lazy_static! {
    pub static ref TEMPLATES: Tera = {
        let mut tera = match Tera::new("templates/**/*") {
            Ok(t) => t,
            Err(e) => {
                println!("Template parsing error(s): {}", e);
                ::std::process::exit(1);
            }
        };
        tera.autoescape_on(vec!["html", ".sql"]);
        tera
    };
}

#[get("/")]
async fn tst() -> Result<HttpResponse, Error> {
    let mut ctx = Context::new();
    let title = String::from("Test");
    ctx.insert("title", &title);
    let body = TEMPLATES.render("index.html", &ctx)
        .map_err(|_| error::ErrorInternalServerError("some Tera error here..."))?;
    Ok(HttpResponse::Ok().body(body))
}

#[actix_web::main]
async fn main() -> std::io::Result<()> {
    HttpServer::new(|| {
        App::new().service(tst)
    })
    .bind("127.0.0.1:8080")?
    .run()
    .await
}

我不想获取some Tera error here...，而是返回实际的tera错误，或者更好的做法是，在stderr输出中记录错误。

[package]
name = "tst"
version = "0.1.0"
edition = "2018"

# See more keys and their definitions at https://doc.rust-lang.org/cargo/reference/manifest.html

[dependencies]
actix-web = "3.3.2"
lazy_static = "1.4.0"
tera = "1.12.1"

Answer 1

正如在此answer中所概述的，actix-web提供了一整套用于转换错误的帮助器函数，因此，为了实现所需的效果，get("/")处理程序应按如下方式进行更改：

#[get("/")]
async fn tst() -> Result<HttpResponse, Error> {
    let mut ctx = Context::new();
    let title = String::from("Test");
    ctx.insert("title", &title);
    match TEMPLATES.render("index.html", &ctx) {
        Ok(body) => Ok(HttpResponse::Ok().body(body)),
        Err(err) => {
            eprintln!("## Tera error: {}", err);
            Err(error::ErrorInternalServerError(err))
        },
    }
}

现在，可以在服务器响应和流程stderr中看到特定的tera错误字符串

> curl -LsD- http://127.0.0.1:8080/
HTTP/1.1 500 Internal Server Error
content-length: 29
content-type: text/plain; charset=utf-8
date: Sat, 18 Sep 2021 18:28:14 GMT

Failed to render 'index.html'