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//! Bindings for emulating a MySQL/MariaDB server. //! //! When developing new databases or caching layers, it can be immensely useful to test your system //! using existing applications. However, this often requires significant work modifying //! applications to use your database over the existing ones. This crate solves that problem by //! acting as a MySQL server, and delegating operations such as querying and query execution to //! user-defined logic. //! //! To start, implement `MysqlShim` for your backend, and create a `MysqlIntermediary` over an //! instance of your backend and a connection stream. The appropriate methods will be called on //! your backend whenever a client issues a `QUERY`, `PREPARE`, or `EXECUTE` command, and you will //! have a chance to respond appropriately. For example, to write a shim that always responds to //! all commands with a "no results" reply: //! //! ``` //! # extern crate msql_srv; //! extern crate mysql; //! # use std::io; //! # use std::net; //! # use std::thread; //! use msql_srv::*; //! //! struct Backend; //! impl<W: io::Write> MysqlShim<W> for Backend { //! type Error = io::Error; //! //! fn on_prepare(&mut self, _: &str, info: StatementMetaWriter<W>) -> io::Result<()> { //! info.reply(42, &[], &[]) //! } //! fn on_execute( //! &mut self, //! _: u32, //! _: ParamParser, //! results: QueryResultWriter<W>, //! ) -> io::Result<()> { //! results.completed(0, 0) //! } //! fn on_close(&mut self, _: u32) {} //! //! fn on_init(&mut self, _: &str, writer: InitWriter<W>) -> io::Result<()> { Ok(()) } //! //! fn on_query(&mut self, _: &str, results: QueryResultWriter<W>) -> io::Result<()> { //! let cols = [ //! Column { //! table: "foo".to_string(), //! column: "a".to_string(), //! coltype: ColumnType::MYSQL_TYPE_LONGLONG, //! colflags: ColumnFlags::empty(), //! }, //! Column { //! table: "foo".to_string(), //! column: "b".to_string(), //! coltype: ColumnType::MYSQL_TYPE_STRING, //! colflags: ColumnFlags::empty(), //! }, //! ]; //! //! let mut rw = results.start(&cols)?; //! rw.write_col(42)?; //! rw.write_col("b's value")?; //! rw.finish() //! } //! } //! //! fn main() { //! let listener = net::TcpListener::bind("127.0.0.1:0").unwrap(); //! let port = listener.local_addr().unwrap().port(); //! //! let jh = thread::spawn(move || { //! if let Ok((s, _)) = listener.accept() { //! MysqlIntermediary::run_on_tcp(Backend, s).unwrap(); //! } //! }); //! //! let mut db = mysql::Conn::new(&format!("mysql://127.0.0.1:{}", port)).unwrap(); //! assert_eq!(db.ping(), true); //! assert_eq!(db.query("SELECT a, b FROM foo").unwrap().count(), 1); //! drop(db); //! jh.join().unwrap(); //! } //! ``` #![deny(missing_docs)] // Note to developers: you can find decent overviews of the protocol at // // https://github.com/cwarden/mysql-proxy/blob/master/doc/protocol.rst // // and // // https://mariadb.com/kb/en/library/clientserver-protocol/ // // Wireshark also does a pretty good job at parsing the MySQL protocol. extern crate byteorder; extern crate chrono; extern crate mysql_common as myc; #[macro_use] extern crate nom; use std::collections::HashMap; use std::io; use std::io::prelude::*; use std::iter; use std::net; pub use myc::constants::{ColumnFlags, ColumnType, StatusFlags}; mod commands; mod errorcodes; mod packet; mod params; mod resultset; mod value; mod writers; /// Meta-information abot a single column, used either to describe a prepared statement parameter /// or an output column. #[derive(Debug, Clone, PartialEq, Eq)] pub struct Column { /// This column's associated table. /// /// Note that this is *technically* the table's alias. pub table: String, /// This column's name. /// /// Note that this is *technically* the column's alias. pub column: String, /// This column's type> pub coltype: ColumnType, /// Any flags associated with this column. /// /// Of particular interest are `ColumnFlags::UNSIGNED_FLAG` and `ColumnFlags::NOT_NULL_FLAG`. pub colflags: ColumnFlags, } pub use errorcodes::ErrorKind; pub use params::{ParamParser, ParamValue, Params}; pub use resultset::{InitWriter, QueryResultWriter, RowWriter, StatementMetaWriter}; pub use value::{ToMysqlValue, Value, ValueInner}; /// Implementors of this trait can be used to drive a MySQL-compatible database backend. pub trait MysqlShim<W: Write> { /// The error type produced by operations on this shim. /// /// Must implement `From<io::Error>` so that transport-level errors can be lifted. type Error: From<io::Error>; /// Called when the client issues a request to prepare `query` for later execution. /// /// The provided [`StatementMetaWriter`](struct.StatementMetaWriter.html) should be used to /// notify the client of the statement id assigned to the prepared statement, as well as to /// give metadata about the types of parameters and returned columns. fn on_prepare(&mut self, query: &str, info: StatementMetaWriter<W>) -> Result<(), Self::Error>; /// Called when the client executes a previously prepared statement. /// /// Any parameters included with the client's command is given in `params`. /// A response to the query should be given using the provided /// [`QueryResultWriter`](struct.QueryResultWriter.html). fn on_execute( &mut self, id: u32, params: ParamParser, results: QueryResultWriter<W>, ) -> Result<(), Self::Error>; /// Called when the client wishes to deallocate resources associated with a previously prepared /// statement. fn on_close(&mut self, stmt: u32); /// Called when the client issues a query for immediate execution. /// /// Results should be returned using the given /// [`QueryResultWriter`](struct.QueryResultWriter.html). fn on_query(&mut self, query: &str, results: QueryResultWriter<W>) -> Result<(), Self::Error>; /// Called when client switches database. fn on_init(&mut self, _: &str, _: InitWriter<W>) -> Result<(), Self::Error> { Ok(()) } } /// A server that speaks the MySQL/MariaDB protocol, and can delegate client commands to a backend /// that implements [`MysqlShim`](trait.MysqlShim.html). pub struct MysqlIntermediary<B, R: Read, W: Write> { shim: B, reader: packet::PacketReader<R>, writer: packet::PacketWriter<W>, } impl<B: MysqlShim<net::TcpStream>> MysqlIntermediary<B, net::TcpStream, net::TcpStream> { /// Create a new server over a TCP stream and process client commands until the client /// disconnects or an error occurs. See also /// [`MysqlIntermediary::run_on`](struct.MysqlIntermediary.html#method.run_on). pub fn run_on_tcp(shim: B, stream: net::TcpStream) -> Result<(), B::Error> { let w = stream.try_clone()?; MysqlIntermediary::run_on(shim, stream, w) } } impl<B: MysqlShim<S>, S: Read + Write + Clone> MysqlIntermediary<B, S, S> { /// Create a new server over a two-way stream and process client commands until the client /// disconnects or an error occurs. See also /// [`MysqlIntermediary::run_on`](struct.MysqlIntermediary.html#method.run_on). pub fn run_on_stream(shim: B, stream: S) -> Result<(), B::Error> { MysqlIntermediary::run_on(shim, stream.clone(), stream) } } #[derive(Default)] struct StatementData { long_data: HashMap<u16, Vec<u8>>, bound_types: Vec<(myc::constants::ColumnType, bool)>, params: u16, } impl<B: MysqlShim<W>, R: Read, W: Write> MysqlIntermediary<B, R, W> { /// Create a new server over two one-way channels and process client commands until the client /// disconnects or an error occurs. pub fn run_on(shim: B, reader: R, writer: W) -> Result<(), B::Error> { let r = packet::PacketReader::new(reader); let w = packet::PacketWriter::new(writer); let mut mi = MysqlIntermediary { shim, reader: r, writer: w, }; mi.init()?; mi.run() } fn init(&mut self) -> Result<(), B::Error> { self.writer.write_all(&[10])?; // protocol 10 // 5.1.10 because that's what Ruby's ActiveRecord requires self.writer.write_all(&b"5.1.10-alpha-msql-proxy\0"[..])?; self.writer.write_all(&[0x08, 0x00, 0x00, 0x00])?; // TODO: connection ID self.writer.write_all(&b";X,po_k}\0"[..])?; // auth seed self.writer.write_all(&[0x00, 0x42])?; // just 4.1 proto self.writer.write_all(&[0x21])?; // UTF8_GENERAL_CI self.writer.write_all(&[0x00, 0x00])?; // status flags self.writer.write_all(&[0x00, 0x00])?; // extended capabilities self.writer.write_all(&[0x00])?; // no plugins self.writer.write_all(&[0x00; 6][..])?; // filler self.writer.write_all(&[0x00; 4][..])?; // filler self.writer.write_all(&b">o6^Wz!/kM}N\0"[..])?; // 4.1+ servers must extend salt self.writer.flush()?; { let (seq, handshake) = self.reader.next()?.unwrap(); let _handshake = commands::client_handshake(&handshake).unwrap().1; self.writer.set_seq(seq + 1); } writers::write_ok_packet(&mut self.writer, 0, 0, StatusFlags::empty())?; self.writer.flush()?; Ok(()) } fn run(mut self) -> Result<(), B::Error> { use commands::Command; let mut stmts: HashMap<u32, _> = HashMap::new(); while let Some((seq, packet)) = self.reader.next()? { self.writer.set_seq(seq + 1); let cmd = commands::parse(&packet).unwrap().1; match cmd { Command::Query(q) => { let w = QueryResultWriter::new(&mut self.writer, false); if q.starts_with(b"SELECT @@") || q.starts_with(b"select @@") { let var = &q[b"SELECT @@".len()..]; match var { b"max_allowed_packet" => { let cols = &[Column { table: String::new(), column: "@@max_allowed_packet".to_owned(), coltype: myc::constants::ColumnType::MYSQL_TYPE_SHORT, colflags: myc::constants::ColumnFlags::UNSIGNED_FLAG, }]; let mut w = w.start(cols)?; w.write_row(iter::once(1024u16))?; w.finish()?; } _ => { w.completed(0, 0)?; } } } else { self.shim.on_query( ::std::str::from_utf8(q) .map_err(|e| io::Error::new(io::ErrorKind::InvalidData, e))?, w, )?; } } Command::Prepare(q) => { let w = StatementMetaWriter { writer: &mut self.writer, stmts: &mut stmts, }; self.shim.on_prepare( ::std::str::from_utf8(q) .map_err(|e| io::Error::new(io::ErrorKind::InvalidData, e))?, w, )?; } Command::Execute { stmt, params } => { let state = stmts.get_mut(&stmt).ok_or(io::Error::new( io::ErrorKind::InvalidData, format!("asked to execute unknown statement {}", stmt), ))?; { let params = params::ParamParser::new(params, state); let w = QueryResultWriter::new(&mut self.writer, true); self.shim.on_execute(stmt, params, w)?; } state.long_data.clear(); } Command::SendLongData { stmt, param, data } => { stmts .get_mut(&stmt) .ok_or(io::Error::new( io::ErrorKind::InvalidData, format!("got long data packet for unknown statement {}", stmt), ))? .long_data .entry(param) .or_insert_with(Vec::new) .extend(data); } Command::Close(stmt) => { self.shim.on_close(stmt); stmts.remove(&stmt); // NOTE: spec dictates no response from server } Command::ListFields(_) => { let cols = &[Column { table: String::new(), column: "not implemented".to_owned(), coltype: myc::constants::ColumnType::MYSQL_TYPE_SHORT, colflags: myc::constants::ColumnFlags::UNSIGNED_FLAG, }]; writers::write_column_definitions(cols, &mut self.writer, true)?; } Command::Init(schema) => { let w = InitWriter { writer: &mut self.writer, }; self.shim.on_init( ::std::str::from_utf8(schema) .map_err(|e| io::Error::new(io::ErrorKind::InvalidData, e))?, w, )?; } Command::Ping => { writers::write_ok_packet(&mut self.writer, 0, 0, StatusFlags::empty())?; } Command::Quit => { break; } } self.writer.flush()?; } Ok(()) } }