Error message for invalid auth credentials could be more helpful

[chris-belcher]

This script uses an incorrect password:

extern crate bitcoincore_rpc;                                                   
use bitcoincore_rpc::{Client, Error, RpcApi, Auth};                             
                                                                                
fn main() -> Result<(), Error> {                                                
                                                                                
    let auth = Auth::UserPass(                                                  
        "regtest-username".to_string(),                                           
        "incorrect-password".to_string()                                           
    );                                                                          
    let rpc = Client::new("http://localhost:18443".to_string(), auth)?;         
                                                                                
    let info = rpc.get_blockchain_info()?;                                      
    println!("info = {:#?}", info);                                             
    println!("best block hash = {}", info.best_block_hash);                     
    Ok(())                                                                      
}

And it produces this error:

Error: JsonRpc(Json(Error("EOF while parsing a value", line: 1, column: 0)))

The error message doesn't mention anything about invalid credentials.

I think what's happening is Bitcoin Core is sending back a HTTP 401 Unauthorized reply, but the rust library still tries to read from the HTTP body. As there's no body it results in a confusing EOF error instead.

I may code a PR myself which fixes this by checking for 401 (I only just started learning rust so this may take a while)

[stevenroose]

That's a good point. We should use the HTTP header. But I'm not sure if this is something that would need to happen at the jsonrpc crate level.

[sgeisler]

@stevenroose yeah, looks like it, jsonrpc ignores error codes.

[stevenroose]

Reading JSON-RPC spec, says

It is transport agnostic in that the concepts can be used within the same process, over sockets, over http, or in many various message passing environments.

So I don't think HTTP status codes are the correct way to handle errors server-side. It should be a 200 OK with a {"error": { ... }} to specify the error. So this is (per spec) a mistake on Core's side.

[stevenroose]

Well in fact I think the jsonrpc spec should return a special error like UnexpectedHttpStatus(u32) when it doesn't encounter 200 OK.