scala.MatchError: java.lang.StackOverflowError

If you hit scala.MatchError: java.lang.StackOverflowError:

Add SBT_OPTS=-Xss4m into Environment Variables would solve the issue.

References:

https://stackoverflow.com/questions/29250004/scala-matcherror-java-lang-stackoverflowerror-of-class-java-lang-stackoverflow

Generate CSV in Playframwork

Example of generate CSV by modify output header.

  def exportCSV = Action {
    val data = "data 1, data 2"

      Ok(data).withHeaders(
          CONTENT_TYPE -> "text/csv",
          CONTENT_DISPOSITION -> "attachment; filename=foo.csv"
      )
  }

This method only suitable if you have small amount of data. If not, I would recommend using streaming.

MongoDB / Salat plugin for Play 2.3

Here is complete installation steps on Salat plugin for Play 2.3:

1. You modify your project/Build.scala:
   

   import sbt._
   import Keys._
   import play.Play.autoImport._
   import PlayKeys._
   import play.twirl.sbt.Import.TwirlKeys
   
   object ApplicationBuild extends Build {
     val appName = "Playframework"
     val appVersion = "2.3.6"
     
     val appDependencies = Seq(
         "se.radley" %% "play-plugins-salat" % "1.5.0"
     )
   
     val main = Project(appName, file(".")).enablePlugins(play.PlayScala).settings(
       version := appVersion,
       libraryDependencies ++= appDependencies,
       routesImport += "se.radley.plugin.salat.Binders._",
       TwirlKeys.templateImports += "org.bson.types.ObjectId"
     )
   }

2. Creating or appending conf/play.plugins

   500:se.radley.plugin.salat.SalatPlugin

3. Continue edit conf/application.conf

   dbplugin = disabled
   evolutionplugin = disabled
   ehcacheplugin = disabled
   
   mongodb.default.db = "mydb"
   
   # Optional values
   #mongodb.default.host = "127.0.0.1"
   #mongodb.default.port = 27017
   #mongodb.default.user = "leon"
   #mongodb.default.password = "123456"
   
   # MongoURI
   # ~~~~~
   # a MongoURI can also be used http://www.mongodb.org/display/DOCS/Connections
   # mongodb.default.uri = "mongodb://127.0.0.1:27017,mongodb.org:1337/salat-test"
   
   # WriteConcern
   # ~~~~~
   # Can be any of the following
   #
   # fsyncsafe - Exceptions are raised for network issues and server errors; Write operations wait for the server to flush data to disk.
   # replicassafe - Exceptions are raised for network issues and server errors; waits for at least 2 servers for the write operation.
   # safe - Exceptions are raised for network issues and server errors; waits on a server for the write operation.
   # normal - Exceptions are raised for network issues but not server errors.
   
   #mongodb.default.writeconcern = "safe"
   
   # Replica sets
   # ~~~~~
   # http://www.mongodb.org/display/DOCS/Why+Replica+Sets
   #
   # To user a replicaset instead of a single host, omit optional values and use the configuration below instead.
   # Since replica sets use public key authentication, user and password won't work together with the replicaset option.
   
   #mongodb.default.replicaset {
   #    host1.host = "10.0.0.1"
   #
   #    host2.host = "10.0.0.2"
   #    host2.port = 27018
   #}
   
   # Mongo Options
   # ~~~~~
   # http://api.mongodb.org/java/2.8.0/com/mongodb/MongoOptions.html
   #
   # For passing custom options to the MongoConnection add the properties under "options". Add just the ones which are different from defaults.
   
   #mongodb.default.options {
   #    connectionsPerHost = 100
   #    threadsAllowedToBlockForConnectionMultiplier = 1000
   #    connectTimeout = 60000
   #}
   

4. Create app/models/mongoContext.scala

   package models
   
   import com.novus.salat.dao._
   import com.novus.salat.annotations._
   import com.mongodb.casbah.Imports._
   import com.novus.salat.{TypeHintFrequency, StringTypeHintStrategy, Context}
   import play.api.Play
   import play.api.Play.current
   
   package object mongoContext {
     implicit val context = {
       val context = new Context {
         val name = "global"
         override val typeHintStrategy = StringTypeHintStrategy(when = TypeHintFrequency.WhenNecessary, typeHint = "_t")
       }
       context.registerGlobalKeyOverride(remapThis = "id", toThisInstead = "_id")
       context.registerClassLoader(Play.classloader)
       context
     }
   }

5. Remove built.sbt as we are using Build.scala. This to avoid below runtime error.

   java.lang.RuntimeException: Overlapping output directories

6. Start your play application using "activator run".

References:
https://github.com/leon/play-salat