wangzl8128 / reactor-kotlin-jdbc

Fluent Reactor JDBC extension functions for Kotlin

Reactor Kotlin JDBC

Fluent, concise, and easy-to-use extension functions targeting JDBC in the Kotlin language with Reactor Core.

This library is a fork of Thomas Nield rxkotlin-jdbc which is inspired by Dave Moten's RxJava-JDBC but seeks to be much more lightweight by leveraging Kotlin functions. This works with threadpool DataSource implementations such as HikariCP, but can also be used with vanilla JDBC Connections.

Extension functions like select(), insert(), and execute() will target both DataSource and JDBC Connection types.

DataSource Usage Examples

When you use a DataSource, a Connection will automatically be pulled from the pool upon subscription and given back when onComplete is called.

val config = HikariConfig()
config.jdbcUrl = "jdbc:sqlite::memory:"
config.minimumIdle = 3
config.maximumPoolSize = 10

val ds = HikariDataSource(config)

//initialize

with(ds) {
    execute("CREATE TABLE USER (ID INTEGER PRIMARY KEY, USERNAME VARCHAR(30) NOT NULL, PASSWORD VARCHAR(30) NOT NULL)")
    execute("INSERT INTO USER (USERNAME,PASSWORD) VALUES (?,?)", "thomasnield", "password123")
    execute("INSERT INTO USER (USERNAME,PASSWORD) VALUES (?,?)", "bobmarshal","batman43")
}

// Retrieve all users
ds.select("SELECT * FROM USER")
        .toFlux { it.getInt("ID") to it.getString("USERNAME") }
        .subscribe(::println)


// Retrieve user with specific ID
ds.select("SELECT * FROM USER WHERE ID = :id")
        .parameter("id", 2)
        .toMono { it.getInt("ID") to it.getString("USERNAME") }
        .subscribeBy(::println)

// Execute insert which return generated keys, and re-select the inserted record with that key
ds.insert("INSERT INTO USER (USERNAME, PASSWORD) VALUES (:username,:password)")
        .parameter("username","josephmarlon")
        .parameter("password","coffeesnob43")
        .toFlux { it.getInt(1) }
        .flatMap {
            conn.select("SELECT * FROM USER WHERE ID = :id")
                    .parameter("id", it)
                    .toMono { "${it.getInt("ID")} ${it.getString("USERNAME")} ${it.getString("PASSWORD")}" }
        }
        .subscribe(::println)

// Run deletion

conn.execute("DELETE FROM USER WHERE ID = :id")
        .parameter("id",2)
        .toMono()
        .subscribeBy(::println)

Connection Usage Example

You can also use a standard Connection with these extension functions, and closing will not happen automatically so you can micromanage the life of that connection.

val connection = DriverManager.getConnection("jdbc:sqlite::memory:")

connection.select("SELECT * FROM USER")
        .toFlux { it.getInt("ID") to it.getString("USERNAME") }
        .subscribe(::println)

Future Developments

• Batch write support
• Flux parameter inputs