Crate fixer 

fixer

A full-featured FIX protocol engine for Rust. Supports FIX versions 4.0 through 5.0SP2 with spec-driven message validation, code-generated type-safe messages, and pluggable storage and logging backends.

Quick Start

A FIX application has three parts: a configuration, an Application trait implementation, and an Acceptor (server) or Initiator (client).

use fixer::{
    acceptor::Acceptor,
    application::Application,
    errors::MessageRejectErrorResult,
    log::screen_log::ScreenLogFactory,
    message::Message,
    registry::send_to_target,
    session::session_id::SessionID,
    settings::Settings,
    store::MemoryStoreFactory,
};
use simple_error::SimpleResult;
use std::sync::Arc;
use tokio::io::BufReader;

struct MyApp;

impl Application for MyApp {
    fn on_create(&self, session_id: &Arc<SessionID>) {
        println!("Session created: {session_id}");
    }
    fn on_logon(&self, session_id: &Arc<SessionID>) {
        println!("Logon: {session_id}");
    }
    fn on_logout(&self, session_id: &Arc<SessionID>) {
        println!("Logout: {session_id}");
    }
    fn to_admin(&self, _msg: &mut Message, _session_id: &Arc<SessionID>) {}
    fn to_app(
        &self, _msg: &mut Message, _session_id: &Arc<SessionID>,
    ) -> SimpleResult<()> {
        Ok(())
    }
    fn from_admin(
        &self, _msg: &Message, _session_id: &Arc<SessionID>,
    ) -> MessageRejectErrorResult {
        Ok(())
    }
    fn from_app(
        &self, msg: &Message, session_id: &Arc<SessionID>,
    ) -> MessageRejectErrorResult {
        // Echo the message back (see examples/echo_server for a full version)
        println!("Received message from {session_id}");
        Ok(())
    }
}

#[tokio::main]
async fn main() -> Result<(), Box<dyn std::error::Error>> {
    let cfg = "\
[DEFAULT]
SocketAcceptPort=5001
SenderCompID=SERVER
TargetCompID=CLIENT
ResetOnLogon=Y

[SESSION]
BeginString=FIX.4.2
";
    let settings = Settings::parse(BufReader::new(cfg.as_bytes())).await?;
    let app: Arc<dyn Application> = Arc::new(MyApp);
    let store_factory = MemoryStoreFactory::new();
    let log_factory = ScreenLogFactory::new();

    let mut acceptor =
        Acceptor::new(app, store_factory, settings, log_factory).await?;
    acceptor.start().await?;

    tokio::signal::ctrl_c().await?;
    acceptor.stop().await;
    Ok(())
}

Architecture

Concept	Description
Application	Your code — callbacks for session events and messages
Acceptor	Listens for inbound FIX connections (server side)
Initiator	Connects to remote FIX servers (client side)
Settings	INI-style configuration with [DEFAULT] and [SESSION] sections
Message	A FIX message with Header, Body, and Trailer FieldMaps
SessionID	Identifies a session by BeginString + SenderCompID + TargetCompID
MessageStoreFactoryEnum	Creates message stores (memory, file, SQL, MongoDB)
LogFactoryEnum	Creates loggers (screen, file, SQL, MongoDB, composite)

Feature Flags

All features are opt-in. By default only the in-memory store and screen/file loggers are available.

Feature	Description
sql_store	SQL-backed message store (SQLite, PostgreSQL, MySQL) via sqlx
sql_log	SQL-backed logging via sqlx
mongo_store	MongoDB-backed message store via mongodb
mongo_log	MongoDB-backed logging via mongodb

Generated Types

The companion crate fixer-fix provides code-generated, type-safe FIX messages. See its documentation for usage with tag, field, enums, and per-version message modules (fix40 through fix50sp2).

Examples

See the examples/ directory for working applications:

• echo_server — Acceptor that echoes messages back to the sender
• trade_client — Initiator that sends orders using generated types

Modules

acceptor

application

config

connection

datadictionary

errors

field

field_map

fileutil

fix_boolean

fix_bytes

fix_decimal

fix_float

fix_int

fix_string

fix_utc_timestamp

initiator

log

message

message_router

msg_type

parser

registry

repeating_group

session

settings

store

tag

tag_value

tls

validation

Constants

BEGIN_STRING_FIX40

BEGIN_STRING_FIX41

BEGIN_STRING_FIX42

BEGIN_STRING_FIX43

BEGIN_STRING_FIX44

BEGIN_STRING_FIXT11