Reqwest POST call gives client (connect) error before giving response. How to get more descriptive error?

1

Rust beginner here. I'm trying to make a post request using basic auth with reqwest.

This is my code 
use std::error::Error;
use reqwest::Client;
use reqwest::Error as rError;
use futures::executor::block_on;

const URL_BASE: &str = "REDACTED";
const USERNAME: &str = "REDACTED";
const PASSWORD: &str = "REDACTED";

pub fn get_token() {
    let res = block_on(get_token_async());
    match res {
        Ok(_) => println!("Success"),
        Err(e) => {
            eprintln!("{}", e);
            if let Some(source) = e.source() {
                eprintln!("{}", source);
            }
        },
    }
}

pub async fn get_token_async() -> Result<(), rError> {
    let client = Client::new();
    let url = String::from(URL_BASE.to_owned() + "/uaa/oauth/token");
    let response = client
        .get(url)
        .basic_auth(USERNAME, Some(PASSWORD))
        .query(&[("grant_type", "client_credentials")])
        .send()
        .await?;
    println!("{}", response.status());
    let token = response.text().await?;
    println!("{}", token);
    Ok(())
}
Main function 
mod modulename;

#[tokio::main]
async fn main() {
    modulename::get_token();
}
Cargo.toml 
[package]
name = "hist_migr"
version = "0.1.0"
edition = "2021"

[dependencies]
futures = "0.3.30"
reqwest = {version = "0.12.5", features = ["json"]}
tokio = {version = "1.39.2", features = ["full"]}

When I run it I get:

error sending request for url (REDACTED/uaa/oauth/token?grant_type=client_credentials)
client error (Connect)

The same link copy and pasted from the error into a browser works fine, returning the expected data...

Is there any way to get a more detailed description than just "client error"? If I can't know why the error happened or get the status code, I have no way of troubleshooting (especially since it works fine elsewhere). I'd appreciate any advice or direction, because at this point I'm out of ideas... Thank you in advance.

2

You are deadlocking the tokio runtime. Call the async function directly:

mod modulename;

#[tokio::main]
async fn main() {
  let _ =  modulename::get_token_async().await;
}
2 Likes
3

Thanks so much for the reply. I changed my main function to this:

#[tokio::main]
async fn main() {
    let res = modulename::get_token_async().await;
    
    match res {
        Ok(_) => println!("Success"),
        Err(e) => {
            eprintln!("{}", e);
            if let Some(source) = e.source() {
                eprintln!("{}", source);
            }
        },
    }
}

But I still get the exact same error:

error sending request for url (...)
client error (Connect)
4

You might need to enable one of the TLS features on reqwest if you happen to be calling an endpoint that requires a secure connection.

1 Like
5

Docs say that default-tls is enabled by default, but I added features = ["json", "default-tls", "native-tls", "rustls-tls"]} anyways. Still the same error. Is that error really as descriptive as its going to be?

6

Debug output ("{:?}") may show more. Chasing .source() recursively may show more.

1 Like
7

Thank you so much! Putting ("{:?}") gives:

error sending request for url (REDACTED/uaa/oauth/token?grant_type=client_credentials)
hyper_util::client::legacy::Error(Connect, Ssl(Error { code: ErrorCode(1), cause: Some(Ssl(ErrorStack([Error { code: 167772294, library: "SSL routines", function: "tls_post_process_server_certificate", reason: "certificate verify failed", file: "../ssl/statem/statem_clnt.c", line: 1889 }]))) }, X509VerifyResult { code: 19, error: "self-signed certificate in certificate chain" }))

which is so much more helpful. Gives me something to work with.

Could you explain what ("{:?}") does? Was I just printing the first element of an array or something before?

8

Placeholders for string formatting are documented in std::fmt. The ? format prints whatever the value's implementation of Debug prints, and most errors have a Debug implementation that gives extensive detail of the error, whereas the Display implementation (used by the {} placeholder) may only give a high-level error message.

2 Likes
9

Ah, I see now. Thank you!

Still trying to wrap my head around this language...

10

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