Added a DatabaseUrlDataSource for use with DATABASE_URL

slick/src/main/scala/slick/jdbc/DatabaseUrlDataSource.scala

@@ -0,0 +1,88 @@
+package slick.jdbc
+
+import scala.language.reflectiveCalls
+
+import java.io.{PrintWriter, Closeable}
+import java.sql._
+import java.util.Properties
+import java.util.logging.Logger
+import javax.sql.DataSource
+
+import slick.SlickException
+import slick.util.{ClassLoaderUtil, Logging, ignoreFollowOnError}
+
+import scala.beans.BeanProperty
+import scala.collection.JavaConverters._
+import scala.util.control.NonFatal
+
+object DatabaseUrlDataSource {
+
+  private val PostgresFullUrl = "^postgres://([a-zA-Z0-9_]+):([^@]+)@([^/]+)/([^\\s]+)$".r
+  private val MysqlFullUrl = "^mysql://([a-zA-Z0-9_]+):([^@]+)@([^/]+)/([^\\s]+)$".r
+  private val MysqlCustomProperties = ".*\\?(.*)".r
+
+  def extractUrl(databaseUrl: Option[String]): String = {
+    extractUrlComponents(Some(databaseUrl.getOrElse(defaultUrl)))._1.orNull
+  }
+
+  def extractUser(databaseUrl: Option[String], default:String): String = {
+    extractUrlComponents(Some(databaseUrl.getOrElse(defaultUrl)))._2.map(_._1).getOrElse(default)
+  }
+
+  def extractPassword(databaseUrl: Option[String], default:String): String = {
+    extractUrlComponents(Some(databaseUrl.getOrElse(defaultUrl)))._2.map(_._2).getOrElse(default)
+  }
+
+  def extractUrlComponents(databaseUrl: Option[String]): (Option[String], Option[(String, String)]) = {
+    databaseUrl match {
+      case Some(PostgresFullUrl(username, password, host, dbname)) =>
+        Some(s"jdbc:postgresql://$host/$dbname") -> Some(username -> password)
+
+      case Some(url @ MysqlFullUrl(username, password, host, dbname)) =>
+        val defaultProperties = "?useUnicode=yes&characterEncoding=UTF-8&connectionCollation=utf8_general_ci"
+        val addDefaultPropertiesIfNeeded = MysqlCustomProperties.findFirstMatchIn(url).map(_ => "").getOrElse(defaultProperties)
+        Some(s"jdbc:mysql://$host/${dbname + addDefaultPropertiesIfNeeded}") -> Some(username -> password)
+
+      case Some(url) =>
+        Some(url) -> None
+
+      case None =>
+        None -> None
+    }
+  }
+
+  def defaultUrl():String = {
+    System.getenv("DATABASE_URL")
+  }
+}
+
+/** A DataSource that wraps the DriverManager API. It can be configured as a Java Bean and used
+  * both stand-alone and as a source for a connection pool. */
+class DatabaseUrlDataSource(
+    /** The Database URL */
+    dbUrl: String,
+    /** Optional user name */
+    dbUrlUser: String = null,
+    /** Optional password */
+    dbUrlPassword: String = null,
+    /** Optional connection properties */
+    dbUrlProperties: Properties = null,
+    /** Name of the `java.sql.Driver` class. This must be set unless a `driverObject` is set
+      * directly or the driver is already registered with the DriverManager. */
+    dbUrlDriverClassName: String = null,
+    /** When `close()` is called, try to deregister a driver that was registered by this instance. */
+    dbUrlDeregisterDriver: Boolean = false,
+    /** The JDBC driver to use. If this is set, `driverClassName` will be ignored. */
+    dbUrlDriverObject: Driver = null,
+    /** The ClassLoader that is used to load `driverClassName` */
+    dbUrlClassLoader: ClassLoader = ClassLoaderUtil.defaultClassLoader
+  ) extends DriverDataSource(
+    DatabaseUrlDataSource.extractUrl(Some(dbUrl)),
+    DatabaseUrlDataSource.extractUser(Some(dbUrl), dbUrlUser),
+    DatabaseUrlDataSource.extractPassword(Some(dbUrl), dbUrlPassword),
+    dbUrlProperties,
+    dbUrlDriverClassName,
+    dbUrlDeregisterDriver,
+    dbUrlDriverObject,
+    dbUrlClassLoader
+  ) { }