golgi/src/utils.rs

//! Utility methods for `golgi`.
use async_std::io::Read;
use std::fmt::Debug;

use kuska_ssb::rpc::{RecvMsg, RequestNo, RpcReader};
use serde_json::Value;

use crate::error::GolgiError;
use crate::messages::{SsbMessageKVT, SsbMessageValue};

/// Function to parse an array of bytes (returned by an rpc call) into a KVT.
///
/// # Arguments
///
/// * `body` - An array of u8 to be parsed.
pub fn kvt_res_parse(body: &[u8]) -> Result<SsbMessageKVT, GolgiError> {
    let value: Value = serde_json::from_slice(body)?;
    let kvt: SsbMessageKVT = serde_json::from_value(value)?;
    Ok(kvt)
}

/// Function to parse an array of bytes (returned by an rpc call) into a String.
///
/// # Arguments
///
/// * `body` - An array of u8 to be parsed.
pub fn string_res_parse(body: &[u8]) -> Result<String, GolgiError> {
    Ok(std::str::from_utf8(body)?.to_string())
}

/// Function to parse an array of bytes (returned by an rpc call) into a serde_json::Value.
///
/// # Arguments
///
/// * `body` - An array of u8 to be parsed.
pub fn json_res_parse(body: &[u8]) -> Result<Value, GolgiError> {
    let message: Value = serde_json::from_slice(body)?;
    Ok(message)
}

/// Function to parse an array of bytes (returned by an rpc call) into an SsbMessageValue
///
/// # Arguments
///
/// * `body` - An array of u8 to be parsed.
pub fn ssb_message_res_parse(body: &[u8]) -> Result<SsbMessageValue, GolgiError> {
    let message: SsbMessageValue = serde_json::from_slice(body)?;
    Ok(message)
}

/// Takes in an rpc request number, and a handling function,
/// and waits for an rpc response which matches the request number,
/// and then calls the handling function on the response.
///
/// # Arguments
///
/// * `rpc_reader` - A `RpcReader` which can return Messages in a loop
/// * `req_no` - A `RequestNo` of the response to listen for
/// * `f` - A function which takes in an array of u8 and returns a Result<T, GolgiError>.
/// This is a function which parses the response from the RpcReader. T is a generic type,
/// so this parse function can return multiple possible types (String, json, custom struct etc.)
pub async fn get_async<'a, R, T, F>(
    rpc_reader: &mut RpcReader<R>,
    req_no: RequestNo,
    f: F,
) -> Result<T, GolgiError>
    where
        R: Read + Unpin,
        F: Fn(&[u8]) -> Result<T, GolgiError>,
        T: Debug,
{
    loop {
        let (id, msg) = rpc_reader.recv().await?;
        if id == req_no {
            match msg {
                RecvMsg::RpcResponse(_type, body) => {
                    return f(&body).map_err(|err| err);
                }
                RecvMsg::ErrorResponse(message) => {
                    return Err(GolgiError::Sbot(message));
                }
                RecvMsg::CancelStreamRespose() => {
                    return Err(GolgiError::Sbot(
                        "sbot returned CancelStreamResponse before any content".to_string(),
                    ));
                }
                _ => {}
            }
        }
    }
}

/// Takes in an rpc request number, and a handling function,
/// and calls the handling function on all RPC responses which match the request number,
/// appending the result of each parsed message to a vector,
/// until a CancelStreamResponse is found, marking the end of the stream,
/// and then finally a result is returned.
///
/// # Arguments
///
/// * `rpc_reader` - A `RpcReader` which can return Messages in a loop
/// * `req_no` - A `RequestNo` of the response to listen for
/// * `f` - A function which takes in an array of u8 and returns a Result<T, GolgiError>.
/// This is a function which parses the response from the RpcReader. T is a generic type,
/// so this parse function can return multiple possible types (String, json, custom struct etc.)
pub async fn get_source_until_eof<'a, R, T, F>(
    rpc_reader: &mut RpcReader<R>,
    req_no: RequestNo,
    f: F,
) -> Result<Vec<T>, GolgiError>
    where
        R: Read + Unpin,
        F: Fn(&[u8]) -> Result<T, GolgiError>,
        T: Debug,
{
    let mut messages: Vec<T> = Vec::new();
    loop {
        let (id, msg) = rpc_reader.recv().await?;
        if id == req_no {
            match msg {
                RecvMsg::RpcResponse(_type, body) => {
                    let parsed_response: Result<T, GolgiError> = f(&body);
                    match parsed_response {
                        Ok(parsed_message) => {
                            messages.push(parsed_message);
                        }
                        Err(err) => {
                            return Err(err);
                        }
                    }
                }
                RecvMsg::ErrorResponse(message) => {
                    return Err(GolgiError::Sbot(message));
                }
                RecvMsg::CancelStreamRespose() => break,
                _ => {}
            }
        }
    }
    Ok(messages)
}



/// Takes in an rpc request number, and a handling function,
/// and calls the handling function on all responses which match the request number,
/// and prints out the result of the handling function.
///
/// This is a function useful for debugging, and only prints the output.
///
/// # Arguments
///
/// * `rpc_reader` - A `RpcReader` which can return Messages in a loop
/// * `req_no` - A `RequestNo` of the response to listen for
/// * `f` - A function which takes in an array of u8 and returns a Result<T, GolgiError>.
/// This is a function which parses the response from the RpcReader. T is a generic type,
/// so this parse function can return multiple possible types (String, json, custom struct etc.)
pub async fn print_source_until_eof<'a, R, T, F>(
    rpc_reader: &mut RpcReader<R>,
    req_no: RequestNo,
    f: F,
) -> Result<(), GolgiError>
    where
        R: Read + Unpin,
        F: Fn(&[u8]) -> Result<T, GolgiError>,
        T: Debug + serde::Deserialize<'a>,
{
    loop {
        let (id, msg) = rpc_reader.recv().await?;
        if id == req_no {
            match msg {
                RecvMsg::RpcResponse(_type, body) => {
                    let display = f(&body)?;
                    println!("{:?}", display);
                }
                RecvMsg::ErrorResponse(message) => {
                    return Err(GolgiError::Sbot(message));
                }
                RecvMsg::CancelStreamRespose() => break,
                _ => {}
            }
        }
    }
    Ok(())
}