Crate msql_srv [−] [src]
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 mysql; use msql_srv::*; struct Backend; impl<W: io::Write> MysqlShim<W> for Backend { fn param_info(&self, stmt: u32) -> &[Column] { &[] } fn on_prepare(&mut self, _: &str, info: StatementMetaWriter<W>) -> io::Result<()> { info.reply(42, &[], &[]) } fn on_execute( &mut self, _: u32, _: Vec<Value>, results: QueryResultWriter<W>, ) -> io::Result<()> { results.completed(0, 0) } fn on_close(&mut self, _: u32) {} fn on_query(&mut self, _: &str, results: QueryResultWriter<W>) -> io::Result<()> { results.completed(0, 0) } } 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(), 0); drop(db); jh.join().unwrap(); }
Structs
Column |
Meta-information abot a single column, used either to describe a prepared statement parameter or an output column. |
ColumnFlags |
MySql column flags |
MysqlIntermediary |
A server that speaks the MySQL/MariaDB protocol, and can delegate client commands to a backend
that implements |
QueryResultWriter |
Convenience type for providing query results to clients. |
RowWriter |
Convenience type for sending rows of a resultset to a client. |
StatementMetaWriter |
Convenience type for responding to a client |
Enums
ColumnType |
Type of MySql column field |
Value |
Client side representation of a value of MySql column. |
Traits
MysqlShim |
Implementors of this trait can be used to drive a MySQL-compatible database backend. |
ToMysqlValue |
Implementors of this trait can be sent as a single resultset value to a MySQL/MariaDB client. |