Fix importing duplicate Configuration class, add dotenv to manage environmental configurations

.gitignore

@@ -23,3 +23,6 @@ release.properties
 dependency-reduced-pom.xml
 buildNumber.properties
 .mvn/timing.properties
+
+#dotenv
+src/main/resources/.env

README.md

@@ -1,2 +1,19 @@
 # OfficeHours
 A web-based system to manage office hours
+
+### Known Issues
+1. [Failed to compile with Scala 2.13](https://github.com/UB-CSE/OfficeHours/issues/174)
+
+### Contribution Guide
+
+#### 1. How to Build this Project
+1. Set up Scala SDK
+2. Mark `src/main/scala` as `Source Root` if need
+3. Set up the local configurations
+    - Rename `src/main/resources/.env.example` to `src/main/resources/.env`
+
+      Revise anything you need to change (Ex: change DB configurations. By default, it will
+      use `List` as DB Driver, that means you don't really need to care about the DB connection
+      if you're not familiar with it, but data(Ex: Queue data), will lose once you restart the project).
+
+4. Build it.

pom.xml

@@ -83,6 +83,13 @@
             </plugin>
 
         </plugins>
+        <resources>
+            <resource>
+                <directory>src/main/resources</directory>
+
+                <targetPath>src/main/resources/.env</targetPath>
+            </resource>
+        </resources>
     </build>
 
 </project>

src/main/resources/.env.example

@@ -0,0 +1,24 @@
+# src/main/resources/.env.example
+# Rename this file into `.env`
+# to make this project work
+
+# ENV
+#
+# Not used by anything yet
+ENV=DEV
+
+# DB_TYPE
+# Type of the database the server gonna use
+# Types are implemented in model.database,
+# Loaded in src/main/scala/model/Configuration
+#
+# "MySQL" || "List"
+# Default: "List"
+DB_TYPE=List
+
+# DB Connection Informations
+# Only need if you're using MySQL as
+
+# DB_URL=jdbc:mysql://localhost/officehours?autoReconnect=true&useUnicode=true&useJDBCCompliantTimezoneShift=true&useLegacyDatetimeCode=false&serverTimezone=UTC
+# DB_USERNAME=root
+# DB_PASSWORD=root

src/main/scala/helper/dotenv/DirtyEnvironmentHack.scala

@@ -0,0 +1,51 @@
+package helper.dotenv
+
+import java.util.Collections
+import scala.util.control.NonFatal
+import scala.util.{Failure, Success, Try}
+
+/**
+ * Rewrite the runtime Environment, embedding entries from the .env file.
+ *
+ * Taken from: https://github.com/mefellows/sbt-dotenv/blob/master/src/main/scala/au/com/onegeek/sbtdotenv/DirtyEnvironmentHack.scala
+ * Original from: http://stackoverflow.com/questions/318239/how-do-i-set-environment-variables-from-java/7201825#7201825
+ *
+ * Created by mfellows on 20/07/2014.
+ */
+object DirtyEnvironmentHack {
+  def setEnv(newEnv: java.util.Map[String, String]): Unit = {
+    Try({
+      val processEnvironmentClass = Class.forName("java.lang.ProcessEnvironment")
+
+      val theEnvironmentField = processEnvironmentClass.getDeclaredField("theEnvironment")
+      theEnvironmentField.setAccessible(true)
+      val env = theEnvironmentField.get(null).asInstanceOf[java.util.Map[String, String]] // scalastyle:off null
+      env.putAll(newEnv)
+
+      val theCaseInsensitiveEnvironmentField = processEnvironmentClass.getDeclaredField("theCaseInsensitiveEnvironment")
+      theCaseInsensitiveEnvironmentField.setAccessible(true)
+      val ciEnv = theCaseInsensitiveEnvironmentField.get(null).asInstanceOf[java.util.Map[String, String]] // scalastyle:off null
+      ciEnv.putAll(newEnv)
+    }) match {
+      case Failure(_: NoSuchFieldException) =>
+        Try({
+          val classes = classOf[Collections].getDeclaredClasses
+          val env = System.getenv
+          classes.filter(_.getName == "java.util.Collections$UnmodifiableMap").foreach(cl => {
+            val field = cl.getDeclaredField("m")
+            field.setAccessible(true)
+            val map = field.get(env).asInstanceOf[java.util.Map[String, String]]
+            map.clear()
+            map.putAll(newEnv)
+          })
+        }) match {
+          case Failure(NonFatal(e2)) =>
+            e2.printStackTrace()
+          case Success(_) =>
+        }
+      case Failure(NonFatal(e1)) =>
+        e1.printStackTrace()
+      case Success(_) =>
+    }
+  }
+}

src/main/scala/helper/dotenv/Dotenv.scala

@@ -0,0 +1,36 @@
+package helper.dotenv
+
+import scala.io.Source
+import scala.util.{Failure, Success, Try}
+import collection.JavaConverters._
+
+object Dotenv {
+  // To load .env file to the Environmental Variables for development
+  def loadEnv(envFilePath: String = ".env"): Unit = {
+    var envLines: List[String] = Try(Source.fromResource(envFilePath).getLines().toList) match {
+      case Success(lines) => lines
+      case Failure(e) => {
+        print("[Warn] Failed to load .env: ")
+        println(e)
+
+        // return empty list if .env not exist
+        List()
+      }
+    }
+
+    for (line <- envLines) {
+      // skip the lines which are commented out
+      if (line.trim != "" && !line.trim.startsWith("#")) {
+        // Split the line by character `=` once
+        var lineContent: Array[String] = line.split("=", 2)
+        if (lineContent.length > 0) {
+          if (lineContent.length == 2) {
+            DirtyEnvironmentHack.setEnv((sys.env ++ Map(
+              lineContent(0) -> lineContent(1)
+            )).asJava)
+          }
+        }
+      }
+    }
+  }
+}

src/main/scala/model/Configuration.scala

@@ -1,7 +1,24 @@
 package model
 
+import scala.util.{Failure, Success, Try}
+
 object Configuration {
 
   val DEV_MODE = true
 
+  /**
+   * DB_TYPE
+   *
+   * Type of the database the server gonna use
+   * Types are implemented in model.database
+   *
+   * "MySQL" || "List"
+   *
+   * default: "List"
+   * */
+  var DB_TYPE: String = Try(sys.env("DB_TYPE")) match {
+    case Success(dbType) => dbType
+    case Failure(e) => "List"
+  }
+
 }

src/main/scala/model/OfficeHoursServer.scala

@@ -1,23 +1,26 @@
 package model
 
+import model.{Configuration => LocalConfiguration}
 import com.corundumstudio.socketio.listener.{DataListener, DisconnectListener}
-import com.corundumstudio.socketio.{AckRequest, Configuration, SocketIOClient, SocketIOServer}
+import com.corundumstudio.socketio.{AckRequest, SocketIOClient, SocketIOServer, Configuration => SocketIOConfiguration}
+import helper.dotenv.Dotenv
 import model.database.{Database, DatabaseAPI, TestingDatabase}
 import play.api.libs.json.{JsValue, Json}
 
 
 class OfficeHoursServer() {
 
-  val database: DatabaseAPI = if(Configuration.DEV_MODE){
-    new TestingDatabase
-  }else{
+  val database: DatabaseAPI = if(LocalConfiguration.DB_TYPE == "MySQL") {
     new Database
+  } else {
+    // fallback to using List as DB if it's "List" or others
+    new TestingDatabase
   }
 
   var usernameToSocket: Map[String, SocketIOClient] = Map()
   var socketToUsername: Map[SocketIOClient, String] = Map()
 
-  val config: Configuration = new Configuration {
+  val config: SocketIOConfiguration = new SocketIOConfiguration {
     setHostname("0.0.0.0")
     setPort(8080)
   }
@@ -40,6 +43,9 @@ class OfficeHoursServer() {
 
 object OfficeHoursServer {
   def main(args: Array[String]): Unit = {
+    // Load environmental variables
+    Dotenv.loadEnv()
+
     new OfficeHoursServer()
   }
 }

src/main/scala/model/database/Database.scala

@@ -7,7 +7,7 @@ import model.StudentInQueue
 
 class Database extends DatabaseAPI{
 
-  val url = "jdbc:mysql://mysql/officehours?autoReconnect=true"
+  val url: String = sys.env("DB_URL")
   val username: String = sys.env("DB_USERNAME")
   val password: String = sys.env("DB_PASSWORD")