Lift - getting access to a database

Since I recently started to play more and more with lift. I discovered that it's not always as easy as you think it is and once you find a solution it was easy indeed.

For example I want to connect to my database server, but have no desire to actually use any form of OR mapping.

So after googleing a bit and woundering how todo this. It's all rather simple.

In your Boot.scala file

def boot {
    // where to search snippet
    LiftRules.addToPackages("code")

    // Build SiteMap
    LiftRules.setSiteMap(sitemap)

    //rest based stuff

    /**
     * connection url for lift
     */
    val vendor = new StandardDBVendor("org.postgresql.Driver","jdbc:postgresql://****/****",Full("username"),Full("password")) with ProtoDBVendor{
      override def maxPoolSize = 100
      override def doNotExpandBeyond = 200
    }
    
    DB.defineConnectionManager(DefaultConnectionIdentifier, vendor)

  }

This basically defines what to connect to and a connection pool with a max of 100 connections.

To actually access this connection and todo something with it, well this is remarkable easy.

          DB.performQuery("select * from data")

scala + lift + json

So since I really really really dislike soap and Java, I decided to play a bit more with scala and rest based web services. Basically parse some JSON strings with scala.

Now after browsing countless articles and remembering the JSON structure, I finally found the 'lift-json' project, which simplifies my live as busy developer a bit.

How to parse JSON with scala?

package edu.ucdavis.fiehnlab.alchemy.core.communication.services.reader

import edu.ucdavis.fiehnlab.alchemy.core.process.types.LibrarySpectra

import net.liftweb.json.parse

import net.liftweb.json.DefaultFormats

/**

 * connects to the alchemy webservice and fetches all registered co

 */

class WebserviceLibraryReader {

  /**

   * internal converter class to simplify things

   */

  case class JsonCompound(name: String, inchikey: String, retentiontime: Double, theoretical: Double, massspectra: String)

  case class CompoundWapper(compound: Array[JsonCompound])

  implicit val formats = DefaultFormats

  /**

   * downloads the compounds for the given URL and returns it as a set of library spectra

   */

  def fetchCompounds(url: String): Set[LibrarySpectra] = {

    val compounds: CompoundWapper = parse("""

        

        {"compound":[{"name":"test","inchikey":"ADVPTQAUNPRNPO-UHFFFAOYSA-N","retentiontime":11111,"theoretical":11,"massspectra":"111:1 112:2 113:3"},{"name":"test","inchikey":"ADVPTQAUNPRNPO-UHFFFAOYSA-N","retentiontime":11111,"theoretical":11,"massspectra":"111:1 112:2 113:3"}]}

        

        """).extract[CompoundWapper]

    compounds.compound.foreach { x: JsonCompound =>

      println(x)

    }

    

    

    null

  }

}

object WebserviceLibraryReader {

  def main(ars: Array[String]) = {

    println(new WebserviceLibraryReader().fetchCompounds("http://localhost:8080/alchemy-admin/services/queryAllCompoundsForMethod/test"))

  }

}

The complete tutorial can be found here