Compare commits
No commits in common. "codecs" and "master" have entirely different histories.
16
.gitignore
vendored
16
.gitignore
vendored
@ -1,16 +0,0 @@
|
||||
# General
|
||||
*.DS_Store
|
||||
*.swp
|
||||
*~
|
||||
|
||||
# Dotty
|
||||
*.class
|
||||
*.tasty
|
||||
*.hasTasty
|
||||
|
||||
# sbt
|
||||
target/
|
||||
|
||||
# Dotty IDE
|
||||
/.dotty-ide-artifact
|
||||
/.dotty-ide.json
|
||||
@ -1,37 +1,5 @@
|
||||
# This configuration is not used for the final grading, you can change it if
|
||||
# you know what you're doing.
|
||||
|
||||
stages:
|
||||
- build
|
||||
- grade
|
||||
|
||||
compile:
|
||||
stage: build
|
||||
image: lampepfl/moocs-dotty:2019-10-16
|
||||
except:
|
||||
- tags
|
||||
tags:
|
||||
- cs210
|
||||
default:
|
||||
image: debian:stable
|
||||
tags: [ generic ]
|
||||
script:
|
||||
- sbt packageSubmission
|
||||
artifacts:
|
||||
expire_in: 1 day
|
||||
paths:
|
||||
- submission.jar
|
||||
|
||||
grade:
|
||||
stage: grade
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||||
except:
|
||||
- tags
|
||||
tags:
|
||||
- cs210
|
||||
image:
|
||||
name: registry.gitlab.com/fnux/cs210-grading-images/progfun2-codecs:20191027-dfbea8aed96096ed3af1cf1958549b97328d4c25
|
||||
entrypoint: [""]
|
||||
allow_failure: true
|
||||
before_script:
|
||||
- mkdir -p /shared/submission/
|
||||
- cp submission.jar /shared/submission/submission.jar
|
||||
script:
|
||||
- cd /grader
|
||||
- /grader/grade | /grader/feedback-printer
|
||||
- echo "It works!"
|
||||
|
||||
8
.vscode/settings.json
vendored
8
.vscode/settings.json
vendored
@ -1,8 +0,0 @@
|
||||
{
|
||||
"dotty": {
|
||||
"trace": {
|
||||
"remoteTracingUrl": "wss://lamppc36.epfl.ch/dotty-remote-tracer/upload/lsp.log",
|
||||
"server": { "format": "JSON", "verbosity": "verbose" }
|
||||
}
|
||||
}
|
||||
}
|
||||
12
README.md
12
README.md
@ -1,6 +1,10 @@
|
||||
# CS-210: Codecs
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||||
# CS-210 Assignments
|
||||
|
||||
Please follow the [instructions from the main course
|
||||
respository](https://gitlab.epfl.ch/lamp/cs-210-functional-programming-2019/blob/master/week11/00-homework8.md).
|
||||
This repository contains your assignments for *Functional Programming* course.
|
||||
Course material and administrative details can be found in the
|
||||
[cs-210-functional-programming-2019 gitlab
|
||||
project](https://gitlab.epfl.ch/lamp/cs-210-functional-programming-2019).
|
||||
|
||||
Grading and submission details can be found [here](https://gitlab.epfl.ch/lamp/cs-210-functional-programming-2019/blob/master/week1/02-grading-and-submission.md).
|
||||
## To select a branch on [gitlab.epfl.ch](https://gitlab.epfl.ch), click on "master" (under project description)
|
||||
|
||||
|
||||
|
||||
BIN
branch-selection.png
Normal file
BIN
branch-selection.png
Normal file
Binary file not shown.
|
After Width: | Height: | Size: 50 KiB |
16
build.sbt
16
build.sbt
@ -1,16 +0,0 @@
|
||||
course := "progfun2"
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||||
assignment := "codecs"
|
||||
name := course.value + "-" + assignment.value
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||||
testSuite := "codecs.CodecsSuite"
|
||||
|
||||
scalaVersion := "0.19.0-RC1"
|
||||
scalacOptions ++= Seq("-deprecation")
|
||||
libraryDependencies ++= Seq(
|
||||
("org.scalacheck" %% "scalacheck" % "1.14.2" % Test).withDottyCompat(scalaVersion.value),
|
||||
("org.typelevel" %% "jawn-parser" % "0.14.2").withDottyCompat(scalaVersion.value),
|
||||
"com.novocode" % "junit-interface" % "0.11" % Test
|
||||
)
|
||||
|
||||
testOptions in Test += Tests.Argument(TestFrameworks.JUnit, "-a", "-v", "-s")
|
||||
|
||||
initialCommands in console := """import codecs.{_, given}"""
|
||||
Binary file not shown.
@ -1,25 +0,0 @@
|
||||
package ch.epfl.lamp
|
||||
|
||||
import sbt._
|
||||
import sbt.Keys._
|
||||
|
||||
/**
|
||||
* Settings shared by all assignments, reused in various tasks.
|
||||
*/
|
||||
object MOOCSettings extends AutoPlugin {
|
||||
|
||||
object autoImport {
|
||||
val course = SettingKey[String]("course")
|
||||
val assignment = SettingKey[String]("assignment")
|
||||
val testSuite = SettingKey[String]("testSuite")
|
||||
val options = SettingKey[Map[String, Map[String, String]]]("options")
|
||||
}
|
||||
|
||||
override def trigger = allRequirements
|
||||
|
||||
override val projectSettings: Seq[Def.Setting[_]] = Seq(
|
||||
parallelExecution in Test := false,
|
||||
// Report test result after each test instead of waiting for every test to finish
|
||||
logBuffered in Test := false
|
||||
)
|
||||
}
|
||||
@ -1,323 +0,0 @@
|
||||
package ch.epfl.lamp
|
||||
|
||||
import sbt._
|
||||
import Keys._
|
||||
|
||||
// import scalaj.http._
|
||||
import java.io.{File, FileInputStream, IOException}
|
||||
import java.nio.file.FileSystems
|
||||
import org.apache.commons.codec.binary.Base64
|
||||
// import play.api.libs.json.{Json, JsObject, JsPath}
|
||||
import scala.util.{Failure, Success, Try}
|
||||
|
||||
import MOOCSettings.autoImport._
|
||||
|
||||
case class AssignmentInfo(
|
||||
key: String,
|
||||
itemId: String,
|
||||
premiumItemId: Option[String],
|
||||
partId: String
|
||||
)
|
||||
|
||||
/**
|
||||
* Provides tasks for submitting the assignment
|
||||
*/
|
||||
object StudentTasks extends AutoPlugin {
|
||||
|
||||
object autoImport {
|
||||
val assignmentInfo = SettingKey[AssignmentInfo]("assignmentInfo")
|
||||
|
||||
val packageSourcesOnly = TaskKey[File]("packageSourcesOnly", "Package the sources of the project")
|
||||
val packageBinWithoutResources = TaskKey[File]("packageBinWithoutResources", "Like packageBin, but without the resources")
|
||||
val packageSubmissionZip = TaskKey[File]("packageSubmissionZip")
|
||||
val packageSubmission = inputKey[Unit]("package solution as an archive file")
|
||||
val runGradingTests = taskKey[Unit]("run black-box tests used for final grading")
|
||||
}
|
||||
|
||||
|
||||
import autoImport._
|
||||
|
||||
override lazy val projectSettings = Seq(
|
||||
packageSubmissionSetting,
|
||||
// submitSetting, // FIXME: restore assignmentInfo setting on assignments
|
||||
runGradingTestsSettings,
|
||||
|
||||
fork := true,
|
||||
connectInput in run := true,
|
||||
outputStrategy := Some(StdoutOutput)
|
||||
) ++ packageSubmissionZipSettings
|
||||
|
||||
lazy val runGradingTestsSettings = runGradingTests := {
|
||||
val testSuiteJar = "grading-tests.jar"
|
||||
if (!new File(testSuiteJar).exists) {
|
||||
throw new MessageOnlyException(s"Could not find tests JarFile: $testSuiteJar")
|
||||
}
|
||||
|
||||
val classPath = s"${(Test / dependencyClasspath).value.map(_.data).mkString(File.pathSeparator)}${File.pathSeparator}$testSuiteJar"
|
||||
val junitProcess =
|
||||
Fork.java.fork(
|
||||
ForkOptions(),
|
||||
"-cp" :: classPath ::
|
||||
"org.junit.runner.JUnitCore" ::
|
||||
(Test / testSuite).value ::
|
||||
Nil
|
||||
)
|
||||
|
||||
// Wait for tests to complete.
|
||||
junitProcess.exitValue()
|
||||
}
|
||||
|
||||
|
||||
/** **********************************************************
|
||||
* SUBMITTING A SOLUTION TO COURSERA
|
||||
*/
|
||||
|
||||
val packageSubmissionZipSettings = Seq(
|
||||
packageSubmissionZip := {
|
||||
val submission = crossTarget.value / "submission.zip"
|
||||
val sources = (packageSourcesOnly in Compile).value
|
||||
val binaries = (packageBinWithoutResources in Compile).value
|
||||
IO.zip(Seq(sources -> "sources.zip", binaries -> "binaries.jar"), submission)
|
||||
submission
|
||||
},
|
||||
artifactClassifier in packageSourcesOnly := Some("sources"),
|
||||
artifact in (Compile, packageBinWithoutResources) ~= (art => art.withName(art.name + "-without-resources"))
|
||||
) ++
|
||||
inConfig(Compile)(
|
||||
Defaults.packageTaskSettings(packageSourcesOnly, Defaults.sourceMappings) ++
|
||||
Defaults.packageTaskSettings(packageBinWithoutResources, Def.task {
|
||||
val relativePaths =
|
||||
(unmanagedResources in Compile).value.flatMap(Path.relativeTo((unmanagedResourceDirectories in Compile).value)(_))
|
||||
(mappings in (Compile, packageBin)).value.filterNot { case (_, path) => relativePaths.contains(path) }
|
||||
})
|
||||
)
|
||||
|
||||
val maxSubmitFileSize = {
|
||||
val mb = 1024 * 1024
|
||||
10 * mb
|
||||
}
|
||||
|
||||
/** Check that the jar exists, isn't empty, isn't crazy big, and can be read
|
||||
* If so, encode jar as base64 so we can send it to Coursera
|
||||
*/
|
||||
def prepareJar(jar: File, s: TaskStreams): String = {
|
||||
val errPrefix = "Error submitting assignment jar: "
|
||||
val fileLength = jar.length()
|
||||
if (!jar.exists()) {
|
||||
s.log.error(errPrefix + "jar archive does not exist\n" + jar.getAbsolutePath)
|
||||
failSubmit()
|
||||
} else if (fileLength == 0L) {
|
||||
s.log.error(errPrefix + "jar archive is empty\n" + jar.getAbsolutePath)
|
||||
failSubmit()
|
||||
} else if (fileLength > maxSubmitFileSize) {
|
||||
s.log.error(errPrefix + "jar archive is too big. Allowed size: " +
|
||||
maxSubmitFileSize + " bytes, found " + fileLength + " bytes.\n" +
|
||||
jar.getAbsolutePath)
|
||||
failSubmit()
|
||||
} else {
|
||||
val bytes = new Array[Byte](fileLength.toInt)
|
||||
val sizeRead = try {
|
||||
val is = new FileInputStream(jar)
|
||||
val read = is.read(bytes)
|
||||
is.close()
|
||||
read
|
||||
} catch {
|
||||
case ex: IOException =>
|
||||
s.log.error(errPrefix + "failed to read sources jar archive\n" + ex.toString)
|
||||
failSubmit()
|
||||
}
|
||||
if (sizeRead != bytes.length) {
|
||||
s.log.error(errPrefix + "failed to read the sources jar archive, size read: " + sizeRead)
|
||||
failSubmit()
|
||||
} else encodeBase64(bytes)
|
||||
}
|
||||
}
|
||||
|
||||
/** Task to package solution to a given file path */
|
||||
lazy val packageSubmissionSetting = packageSubmission := {
|
||||
val args: Seq[String] = Def.spaceDelimited("[path]").parsed
|
||||
val s: TaskStreams = streams.value // for logging
|
||||
val jar = (packageSubmissionZip in Compile).value
|
||||
|
||||
val base64Jar = prepareJar(jar, s)
|
||||
|
||||
val path = args.headOption.getOrElse((baseDirectory.value / "submission.jar").absolutePath)
|
||||
scala.tools.nsc.io.File(path).writeAll(base64Jar)
|
||||
}
|
||||
|
||||
/*
|
||||
/** Task to submit a solution to coursera */
|
||||
val submit = inputKey[Unit]("submit solution to Coursera")
|
||||
lazy val submitSetting = submit := {
|
||||
val args: Seq[String] = Def.spaceDelimited("<arg>").parsed
|
||||
val s: TaskStreams = streams.value // for logging
|
||||
val jar = (packageSubmissionZip in Compile).value
|
||||
|
||||
val assignmentDetails = assignmentInfo.value
|
||||
val assignmentKey = assignmentDetails.key
|
||||
val courseName =
|
||||
course.value match {
|
||||
case "capstone" => "scala-capstone"
|
||||
case "bigdata" => "scala-spark-big-data"
|
||||
case other => other
|
||||
}
|
||||
|
||||
val partId = assignmentDetails.partId
|
||||
val itemId = assignmentDetails.itemId
|
||||
val premiumItemId = assignmentDetails.premiumItemId
|
||||
|
||||
val (email, secret) = args match {
|
||||
case email :: secret :: Nil =>
|
||||
(email, secret)
|
||||
case _ =>
|
||||
val inputErr =
|
||||
s"""|Invalid input to `submit`. The required syntax for `submit` is:
|
||||
|submit <email-address> <submit-token>
|
||||
|
|
||||
|The submit token is NOT YOUR LOGIN PASSWORD.
|
||||
|It can be obtained from the assignment page:
|
||||
|https://www.coursera.org/learn/$courseName/programming/$itemId
|
||||
|${
|
||||
premiumItemId.fold("") { id =>
|
||||
s"""or (for premium learners):
|
||||
|https://www.coursera.org/learn/$courseName/programming/$id
|
||||
""".stripMargin
|
||||
}
|
||||
}
|
||||
""".stripMargin
|
||||
s.log.error(inputErr)
|
||||
failSubmit()
|
||||
}
|
||||
|
||||
val base64Jar = prepareJar(jar, s)
|
||||
val json =
|
||||
s"""|{
|
||||
| "assignmentKey":"$assignmentKey",
|
||||
| "submitterEmail":"$email",
|
||||
| "secret":"$secret",
|
||||
| "parts":{
|
||||
| "$partId":{
|
||||
| "output":"$base64Jar"
|
||||
| }
|
||||
| }
|
||||
|}""".stripMargin
|
||||
|
||||
def postSubmission[T](data: String): Try[HttpResponse[String]] = {
|
||||
val http = Http("https://www.coursera.org/api/onDemandProgrammingScriptSubmissions.v1")
|
||||
val hs = List(
|
||||
("Cache-Control", "no-cache"),
|
||||
("Content-Type", "application/json")
|
||||
)
|
||||
s.log.info("Connecting to Coursera...")
|
||||
val response = Try(http.postData(data)
|
||||
.headers(hs)
|
||||
.option(HttpOptions.connTimeout(10000)) // scalaj default timeout is only 100ms, changing that to 10s
|
||||
.asString) // kick off HTTP POST
|
||||
response
|
||||
}
|
||||
|
||||
val connectMsg =
|
||||
s"""|Attempting to submit "${assignment.value}" assignment in "$courseName" course
|
||||
|Using:
|
||||
|- email: $email
|
||||
|- submit token: $secret""".stripMargin
|
||||
s.log.info(connectMsg)
|
||||
|
||||
def reportCourseraResponse(response: HttpResponse[String]): Unit = {
|
||||
val code = response.code
|
||||
val respBody = response.body
|
||||
|
||||
/* Sample JSON response from Coursera
|
||||
{
|
||||
"message": "Invalid email or token.",
|
||||
"details": {
|
||||
"learnerMessage": "Invalid email or token."
|
||||
}
|
||||
}
|
||||
*/
|
||||
|
||||
// Success, Coursera responds with 2xx HTTP status code
|
||||
if (response.is2xx) {
|
||||
val successfulSubmitMsg =
|
||||
s"""|Successfully connected to Coursera. (Status $code)
|
||||
|
|
||||
|Assignment submitted successfully!
|
||||
|
|
||||
|You can see how you scored by going to:
|
||||
|https://www.coursera.org/learn/$courseName/programming/$itemId/
|
||||
|${
|
||||
premiumItemId.fold("") { id =>
|
||||
s"""or (for premium learners):
|
||||
|https://www.coursera.org/learn/$courseName/programming/$id
|
||||
""".stripMargin
|
||||
}
|
||||
}
|
||||
|and clicking on "My Submission".""".stripMargin
|
||||
s.log.info(successfulSubmitMsg)
|
||||
}
|
||||
|
||||
// Failure, Coursera responds with 4xx HTTP status code (client-side failure)
|
||||
else if (response.is4xx) {
|
||||
val result = Try(Json.parse(respBody)).toOption
|
||||
val learnerMsg = result match {
|
||||
case Some(resp: JsObject) =>
|
||||
(JsPath \ "details" \ "learnerMessage").read[String].reads(resp).get
|
||||
case Some(x) => // shouldn't happen
|
||||
"Could not parse Coursera's response:\n" + x
|
||||
case None =>
|
||||
"Could not parse Coursera's response:\n" + respBody
|
||||
}
|
||||
val failedSubmitMsg =
|
||||
s"""|Submission failed.
|
||||
|There was something wrong while attempting to submit.
|
||||
|Coursera says:
|
||||
|$learnerMsg (Status $code)""".stripMargin
|
||||
s.log.error(failedSubmitMsg)
|
||||
}
|
||||
|
||||
// Failure, Coursera responds with 5xx HTTP status code (server-side failure)
|
||||
else if (response.is5xx) {
|
||||
val failedSubmitMsg =
|
||||
s"""|Submission failed.
|
||||
|Coursera seems to be unavailable at the moment (Status $code)
|
||||
|Check https://status.coursera.org/ and try again in a few minutes.
|
||||
""".stripMargin
|
||||
s.log.error(failedSubmitMsg)
|
||||
}
|
||||
|
||||
// Failure, Coursera repsonds with an unexpected status code
|
||||
else {
|
||||
val failedSubmitMsg =
|
||||
s"""|Submission failed.
|
||||
|Coursera replied with an unexpected code (Status $code)
|
||||
""".stripMargin
|
||||
s.log.error(failedSubmitMsg)
|
||||
}
|
||||
}
|
||||
|
||||
// kick it all off, actually make request
|
||||
postSubmission(json) match {
|
||||
case Success(resp) => reportCourseraResponse(resp)
|
||||
case Failure(e) =>
|
||||
val failedConnectMsg =
|
||||
s"""|Connection to Coursera failed.
|
||||
|There was something wrong while attempting to connect to Coursera.
|
||||
|Check your internet connection.
|
||||
|${e.toString}""".stripMargin
|
||||
s.log.error(failedConnectMsg)
|
||||
}
|
||||
|
||||
}
|
||||
*/
|
||||
|
||||
def failSubmit(): Nothing = {
|
||||
sys.error("Submission failed")
|
||||
}
|
||||
|
||||
/**
|
||||
* *****************
|
||||
* DEALING WITH JARS
|
||||
*/
|
||||
def encodeBase64(bytes: Array[Byte]): String =
|
||||
new String(Base64.encodeBase64(bytes))
|
||||
}
|
||||
@ -1 +0,0 @@
|
||||
sbt.version=1.2.8
|
||||
@ -1,7 +0,0 @@
|
||||
// Used for base64 encoding
|
||||
libraryDependencies += "commons-codec" % "commons-codec" % "1.10"
|
||||
|
||||
// Used for Coursera submussion
|
||||
// libraryDependencies += "org.scalaj" %% "scalaj-http" % "2.3.0"
|
||||
// libraryDependencies += "com.typesafe.play" %% "play-json" % "2.6.9"
|
||||
|
||||
@ -1,2 +0,0 @@
|
||||
addSbtPlugin("io.get-coursier" % "sbt-coursier" % "2.0.0-RC3-5")
|
||||
addSbtPlugin("ch.epfl.lamp" % "sbt-dotty" % "0.3.4")
|
||||
@ -1,283 +0,0 @@
|
||||
package codecs
|
||||
|
||||
/**
|
||||
* A data type modeling JSON values.
|
||||
*
|
||||
* For example, the `42` integer JSON value can be modeled as `Json.Num(42)`
|
||||
*/
|
||||
sealed trait Json {
|
||||
/**
|
||||
* Try to decode this JSON value into a value of type `A` by using
|
||||
* the given decoder.
|
||||
*
|
||||
* Note that you have to explicitly fix `A` type parameter when you call the method:
|
||||
*
|
||||
* {{{
|
||||
* someJsonValue.decodeAs[User] // OK
|
||||
* someJsonValue.decodeAs // Wrong!
|
||||
* }}}
|
||||
*/
|
||||
def decodeAs[A](given decoder: Decoder[A]): Option[A] = decoder.decode(this)
|
||||
}
|
||||
|
||||
object Json {
|
||||
/** The JSON `null` value */
|
||||
case object Null extends Json
|
||||
/** JSON boolean values */
|
||||
case class Bool(value: Boolean) extends Json
|
||||
/** JSON numeric values */
|
||||
case class Num(value: BigDecimal) extends Json
|
||||
/** JSON string values */
|
||||
case class Str(value: String) extends Json
|
||||
/** JSON objects */
|
||||
case class Obj(fields: Map[String, Json]) extends Json
|
||||
/** JSON arrays */
|
||||
case class Arr(items: List[Json]) extends Json
|
||||
}
|
||||
|
||||
/**
|
||||
* A type class that turns a value of type `A` into its JSON representation.
|
||||
*/
|
||||
trait Encoder[-A] {
|
||||
|
||||
def encode(value: A): Json
|
||||
|
||||
/**
|
||||
* Transforms this `Encoder[A]` into an `Encoder[B]`, given a transformation function
|
||||
* from `B` to `A`.
|
||||
*
|
||||
* For instance, given a `Encoder[String]`, we can get an `Encoder[UUID]`:
|
||||
*
|
||||
* {{{
|
||||
* def uuidEncoder(given stringEncoder: Encoder[String]): Encoder[UUID] =
|
||||
* stringEncoder.transform[UUID](uuid => uuid.toString)
|
||||
* }}}
|
||||
*
|
||||
* This operation is also known as ?contramap?.
|
||||
*/
|
||||
def transform[B](f: B => A): Encoder[B] =
|
||||
Encoder.fromFunction[B](value => this.encode(f(value)))
|
||||
}
|
||||
|
||||
object Encoder extends GivenEncoders {
|
||||
|
||||
/**
|
||||
* Convenient method for creating an instance of encoder from a function `f`
|
||||
*/
|
||||
def fromFunction[A](f: A => Json) = new Encoder[A] {
|
||||
def encode(value: A): Json = f(value)
|
||||
}
|
||||
|
||||
}
|
||||
|
||||
trait GivenEncoders {
|
||||
|
||||
/** An encoder for the `Unit` value */
|
||||
given Encoder[Unit] = Encoder.fromFunction(_ => Json.Null)
|
||||
|
||||
/** An encoder for `Int` values */
|
||||
given Encoder[Int] = Encoder.fromFunction(n => Json.Num(BigDecimal(n)))
|
||||
|
||||
/** An encoder for `String` values */
|
||||
given Encoder[String] =
|
||||
Encoder.fromFunction(str => Json.Str(str))
|
||||
|
||||
/** An encoder for `Boolean` values */
|
||||
given Encoder[Boolean] =
|
||||
Encoder.fromFunction(v => Json.Bool(v))
|
||||
|
||||
/**
|
||||
* Encodes a list of values of type `A` into a JSON array containing
|
||||
* the list elements encoded with the given `encoder`
|
||||
*/
|
||||
given [A](given encoder: Encoder[A]): Encoder[List[A]] =
|
||||
Encoder.fromFunction(as => Json.Arr(as.map(encoder.encode)))
|
||||
|
||||
}
|
||||
|
||||
/**
|
||||
* A specialization of `Encoder` that returns JSON objects only
|
||||
*/
|
||||
trait ObjectEncoder[-A] extends Encoder[A] {
|
||||
// Refines the encoding result to `Json.Obj`
|
||||
def encode(value: A): Json.Obj
|
||||
|
||||
/**
|
||||
* Combines `this` encoder with `that` encoder.
|
||||
* Returns an encoder producing a JSON object containing both
|
||||
* fields of `this` encoder and fields of `that` encoder.
|
||||
*/
|
||||
def zip[B](that: ObjectEncoder[B]): ObjectEncoder[(A, B)] =
|
||||
ObjectEncoder.fromFunction { (a, b) =>
|
||||
Json.Obj(this.encode(a).fields ++ that.encode(b).fields)
|
||||
}
|
||||
}
|
||||
|
||||
object ObjectEncoder {
|
||||
|
||||
/**
|
||||
* Convenient method for creating an instance of object encoder from a function `f`
|
||||
*/
|
||||
def fromFunction[A](f: A => Json.Obj): ObjectEncoder[A] = new ObjectEncoder[A] {
|
||||
def encode(value: A): Json.Obj = f(value)
|
||||
}
|
||||
|
||||
/**
|
||||
* An encoder for values of type `A` that produces a JSON object with one field
|
||||
* named according to the supplied `name` and containing the encoded value.
|
||||
*/
|
||||
def field[A](name: String)(given encoder: Encoder[A]): ObjectEncoder[A] =
|
||||
ObjectEncoder.fromFunction(a => Json.Obj(Map(name -> encoder.encode(a))))
|
||||
|
||||
}
|
||||
|
||||
/**
|
||||
* The dual of an encoder. Decodes a serialized value into its initial type `A`.
|
||||
*/
|
||||
trait Decoder[+A] {
|
||||
/**
|
||||
* @param data The data to de-serialize
|
||||
* @return The decoded value wrapped in `Some`, or `None` if decoding failed
|
||||
*/
|
||||
def decode(data: Json): Option[A]
|
||||
|
||||
/**
|
||||
* Combines `this` decoder with `that` decoder.
|
||||
* Returns a decoder that invokes both `this` decoder and `that`
|
||||
* decoder and returns a pair of decoded value in case both succeed,
|
||||
* or `None` if at least one failed.
|
||||
*/
|
||||
def zip[B](that: Decoder[B]): Decoder[(A, B)] =
|
||||
Decoder.fromFunction { json =>
|
||||
this.decode(json).zip(that.decode(json))
|
||||
}
|
||||
|
||||
/**
|
||||
* Transforms this `Decoder[A]` into a `Decoder[B]`, given a transformation function
|
||||
* from `A` to `B`.
|
||||
*
|
||||
* This operation is also known as ?map?.
|
||||
*/
|
||||
def transform[B](f: A => B): Decoder[B] =
|
||||
Decoder.fromFunction(json => this.decode(json).map(f))
|
||||
}
|
||||
|
||||
object Decoder extends GivenDecoders {
|
||||
|
||||
/**
|
||||
* Convenient method to build a decoder instance from a function `f`
|
||||
*/
|
||||
def fromFunction[A](f: Json => Option[A]): Decoder[A] = new Decoder[A] {
|
||||
def decode(data: Json): Option[A] = f(data)
|
||||
}
|
||||
|
||||
/**
|
||||
* Alternative method for creating decoder instances
|
||||
*/
|
||||
def fromPartialFunction[A](pf: PartialFunction[Json, A]): Decoder[A] =
|
||||
fromFunction(pf.lift)
|
||||
|
||||
}
|
||||
|
||||
trait GivenDecoders {
|
||||
|
||||
/** A decoder for the `Unit` value */
|
||||
given Decoder[Unit] =
|
||||
Decoder.fromPartialFunction { case Json.Null => () }
|
||||
|
||||
/** A decoder for `Int` values. Hint: use the `isValidInt` method of `BigDecimal`. */
|
||||
// TODO Define a given `Decoder[Int]` instance
|
||||
given Decoder[Int] =
|
||||
Decoder.fromFunction{ case Json.Num(v) => if v.isValidInt then Some(v.intValue) else None
|
||||
case _ => None}
|
||||
|
||||
/** A decoder for `String` values */
|
||||
// TODO Define a given `Decoder[String]` instance
|
||||
given Decoder[String] =
|
||||
Decoder.fromPartialFunction{ case Json.Str(str) => str}
|
||||
|
||||
/** A decoder for `Boolean` values */
|
||||
// TODO Define a given `Decoder[Boolean]` instance
|
||||
given Decoder[Boolean] =
|
||||
Decoder.fromPartialFunction{ case Json.Bool(v) => v}
|
||||
/**
|
||||
* A decoder for JSON arrays. It decodes each item of the array
|
||||
* using the given `decoder`. The resulting decoder succeeds only
|
||||
* if all the JSON array items are successfully decoded.
|
||||
*/
|
||||
given [A](given decoder: Decoder[A]): Decoder[List[A]] =
|
||||
Decoder.fromFunction {
|
||||
case Json.Arr(items: List[Json]) => Some(items.map(v => decoder.decode(v).get))
|
||||
case _ => None
|
||||
}
|
||||
|
||||
/**
|
||||
* A decoder for JSON objects. It decodes the value of a field of
|
||||
* the supplied `name` using the given `decoder`.
|
||||
*/
|
||||
def field[A](name: String)(given decoder: Decoder[A]): Decoder[A] =
|
||||
Decoder.fromFunction{
|
||||
case Json.Obj(field: Map[String, Json]) => decoder.decode(field.get(name).get)
|
||||
case _ => None
|
||||
}
|
||||
|
||||
}
|
||||
|
||||
case class Person(name: String, age: Int)
|
||||
|
||||
object Person extends PersonCodecs
|
||||
|
||||
trait PersonCodecs {
|
||||
|
||||
/** The encoder for `Person` */
|
||||
given Encoder[Person] =
|
||||
ObjectEncoder.field[String]("name")
|
||||
.zip(ObjectEncoder.field[Int]("age"))
|
||||
.transform[Person](user => (user.name, user.age))
|
||||
|
||||
/** The corresponding decoder for `Person` */
|
||||
given Decoder[Person] ={
|
||||
Decoder.field[String]("name").zip(Decoder.field[Int]("age")).transform[Person](user => Person(user._1, user._2))
|
||||
}
|
||||
|
||||
}
|
||||
|
||||
case class Contacts(people: List[Person])
|
||||
|
||||
object Contacts extends ContactsCodecs
|
||||
|
||||
trait ContactsCodecs {
|
||||
|
||||
// TODO Define the encoder and the decoder for `Contacts`
|
||||
// The JSON representation of a value of type `Contacts` should be
|
||||
// a JSON object with a single field named ?people? containing an
|
||||
// array of values of type `Person` (reuse the `Person` codecs)
|
||||
given Encoder[Contacts] =
|
||||
ObjectEncoder.field[List[Person]]("people").transform[Contacts](c => c.people)
|
||||
|
||||
given Decoder[Contacts] =
|
||||
Decoder.field[List[Person]]("people").transform[Contacts](p => Contacts(p))
|
||||
|
||||
}
|
||||
|
||||
// In case you want to try your code, here is a simple `Main`
|
||||
// that can be used as a starting point. Otherwise, you can use
|
||||
// the REPL (use the `console` sbt task).
|
||||
object Main {
|
||||
|
||||
def main(args: Array[String]): Unit = {
|
||||
println(renderJson(42))
|
||||
println(renderJson("foo"))
|
||||
|
||||
val maybeJsonString = parseJson(""" "foo" """)
|
||||
val maybeJsonObj = parseJson(""" { "name": "Alice", "age": 42 } """)
|
||||
val maybeJsonObj2 = parseJson(""" { "name": "Alice", "age": "42" } """)
|
||||
// Uncomment the following lines as you progress in the assignment
|
||||
println(maybeJsonString.flatMap(_.decodeAs[Int]))
|
||||
println(maybeJsonString.flatMap(_.decodeAs[String]))
|
||||
println(maybeJsonObj.flatMap(_.decodeAs[Person]))
|
||||
println(maybeJsonObj2.flatMap(_.decodeAs[Person]))
|
||||
println(renderJson(Person("Bob", 66)))
|
||||
}
|
||||
|
||||
}
|
||||
@ -1,74 +0,0 @@
|
||||
package codecs
|
||||
|
||||
import org.typelevel.jawn.{ Parser, SimpleFacade }
|
||||
import scala.collection.mutable
|
||||
import scala.util.Try
|
||||
|
||||
// Utility methods that decode values from `String` JSON blobs, and
|
||||
// render values to `String` JSON blobs
|
||||
|
||||
/**
|
||||
* Parse a JSON document contained in a `String` value into a `Json` value, returns
|
||||
* `None` in case the supplied `s` value is not a valid JSON document.
|
||||
*/
|
||||
def parseJson(s: String): Option[Json] = Parser.parseFromString[Json](s).toOption
|
||||
|
||||
/**
|
||||
* Parse the JSON value from the supplied `s` parameter, and then try to decode
|
||||
* it as a value of type `A` using the given `decoder`.
|
||||
*
|
||||
* Returns `None` if JSON parsing failed, or if decoding failed.
|
||||
*/
|
||||
def parseAndDecode[A](s: String)(given decoder: Decoder[A]): Option[A] =
|
||||
for {
|
||||
json <- parseJson(s)
|
||||
a <- decoder.decode(json)
|
||||
} yield a
|
||||
|
||||
/**
|
||||
* Render the supplied `value` into JSON using the given `encoder`.
|
||||
*/
|
||||
def renderJson[A](value: A)(given encoder: Encoder[A]): String =
|
||||
render(encoder.encode(value))
|
||||
|
||||
private def render(json: Json): String = json match {
|
||||
case Json.Null => "null"
|
||||
case Json.Bool(b) => b.toString
|
||||
case Json.Num(n) => n.toString
|
||||
case Json.Str(s) => renderString(s)
|
||||
case Json.Arr(vs) => vs.map(render).mkString("[", ",", "]")
|
||||
case Json.Obj(vs) => vs.map { case (k, v) => s"${renderString(k)}:${render(v)}" }.mkString("{", ",", "}")
|
||||
}
|
||||
|
||||
private def renderString(s: String): String = {
|
||||
val sb = new StringBuilder
|
||||
sb.append('"')
|
||||
var i = 0
|
||||
val len = s.length
|
||||
while (i < len) {
|
||||
s.charAt(i) match {
|
||||
case '"' => sb.append("\\\"")
|
||||
case '\\' => sb.append("\\\\")
|
||||
case '\b' => sb.append("\\b")
|
||||
case '\f' => sb.append("\\f")
|
||||
case '\n' => sb.append("\\n")
|
||||
case '\r' => sb.append("\\r")
|
||||
case '\t' => sb.append("\\t")
|
||||
case c =>
|
||||
if (c < ' ') sb.append("\\u%04x" format c.toInt)
|
||||
else sb.append(c)
|
||||
}
|
||||
i += 1
|
||||
}
|
||||
sb.append('"').toString
|
||||
}
|
||||
|
||||
given SimpleFacade[Json] {
|
||||
def jnull() = Json.Null
|
||||
def jtrue() = Json.Bool(true)
|
||||
def jfalse() = Json.Bool(false)
|
||||
def jnum(s: CharSequence, decIndex: Int, expIndex: Int) = Json.Num(BigDecimal(s.toString))
|
||||
def jstring(s: CharSequence) = Json.Str(s.toString)
|
||||
def jarray(vs: List[Json]) = Json.Arr(vs)
|
||||
def jobject(vs: Map[String, Json]) = Json.Obj(vs)
|
||||
}
|
||||
@ -1,115 +0,0 @@
|
||||
package codecs
|
||||
|
||||
import org.scalacheck
|
||||
import org.scalacheck.{ Gen, Prop }
|
||||
import org.scalacheck.Prop.propBoolean
|
||||
import org.junit.{ Assert, Test }
|
||||
import scala.reflect.ClassTag
|
||||
|
||||
class CodecsSuite extends GivenEncoders, GivenDecoders, PersonCodecs, ContactsCodecs, TestEncoders, TestDecoders {
|
||||
|
||||
def checkProperty(prop: Prop): Unit = {
|
||||
val result = scalacheck.Test.check(scalacheck.Test.Parameters.default, prop)
|
||||
def fail(labels: Set[String], fallback: String): Nothing =
|
||||
if labels.isEmpty then throw new AssertionError(fallback)
|
||||
else throw new AssertionError(labels.mkString(". "))
|
||||
result.status match {
|
||||
case scalacheck.Test.Passed | _: scalacheck.Test.Proved => ()
|
||||
case scalacheck.Test.Failed(_, labels) => fail(labels, "A property failed.")
|
||||
case scalacheck.Test.PropException(_, e, labels) => fail(labels, s"An exception was thrown during property evaluation: $e.")
|
||||
case scalacheck.Test.Exhausted => fail(Set.empty, "Unable to generate data.")
|
||||
}
|
||||
}
|
||||
|
||||
/**
|
||||
* Check that a value of an arbitrary type `A` can be encoded and then successfully
|
||||
* decoded with the given pair of encoder and decoder.
|
||||
*/
|
||||
def encodeAndThenDecodeProp[A](a: A)(given encA: Encoder[A], decA: Decoder[A]): Prop = {
|
||||
val maybeDecoded = decA.decode(encA.encode(a))
|
||||
maybeDecoded.contains(a) :| s"Encoded value '$a' was not successfully decoded. Got '$maybeDecoded'."
|
||||
}
|
||||
|
||||
@Test def `it is possible to encode and decode the 'Unit' value (0pts)`(): Unit = {
|
||||
checkProperty(Prop.forAll((unit: Unit) => encodeAndThenDecodeProp(unit)))
|
||||
}
|
||||
|
||||
@Test def `it is possible to encode and decode 'Int' values (1pt)`(): Unit = {
|
||||
checkProperty(Prop.forAll((x: Int) => encodeAndThenDecodeProp(x)))
|
||||
}
|
||||
|
||||
@Test def `the 'Int' decoder should reject invalid 'Int' values (2pts)`(): Unit = {
|
||||
val decoded = summon[Decoder[Int]].decode(Json.Num(4.2))
|
||||
assert(decoded.isEmpty, "decoding 4.2 as an integer value should fail")
|
||||
}
|
||||
|
||||
@Test def `a 'String' value should be encoded as a JSON string (1pt)`(): Unit = {
|
||||
assert(summon[Encoder[String]].encode("foo") == Json.Str("foo"))
|
||||
}
|
||||
|
||||
@Test def `it is possible to encode and decode 'String' values (1pt)`(): Unit = {
|
||||
checkProperty(Prop.forAll((s: String) => encodeAndThenDecodeProp(s)))
|
||||
}
|
||||
|
||||
@Test def `a 'Boolean' value should be encoded as a JSON boolean (1pt)`(): Unit = {
|
||||
val encoder = summon[Encoder[Boolean]]
|
||||
assert(encoder.encode(true) == Json.Bool(true))
|
||||
assert(encoder.encode(false) == Json.Bool(false))
|
||||
}
|
||||
|
||||
@Test def `it is possible to encode and decode 'Boolean' values (1pt)`(): Unit = {
|
||||
checkProperty(Prop.forAll((b: Boolean) => encodeAndThenDecodeProp(b)))
|
||||
}
|
||||
|
||||
@Test def `a 'List[A]' value should be encoded as a JSON array (0pts)`(): Unit = {
|
||||
val xs = 1 :: 2 :: Nil
|
||||
val encoder = summon[Encoder[List[Int]]]
|
||||
assert(encoder.encode(xs) == Json.Arr(List(Json.Num(1), Json.Num(2))))
|
||||
}
|
||||
|
||||
@Test def `it is possible to encode and decode lists (5pts)`(): Unit = {
|
||||
checkProperty(Prop.forAll((xs: List[Int]) => encodeAndThenDecodeProp(xs)))
|
||||
}
|
||||
|
||||
@Test def `a 'Person' value should be encoded as a JSON object (1pt)`(): Unit = {
|
||||
val person = Person("Alice", 42)
|
||||
val json = Json.Obj(Map("name" -> Json.Str("Alice"), "age" -> Json.Num(42)))
|
||||
val encoder = summon[Encoder[Person]]
|
||||
assert(encoder.encode(person) == json)
|
||||
}
|
||||
|
||||
@Test def `it is possible to encode and decode people (4pts)`(): Unit = {
|
||||
checkProperty(Prop.forAll((s: String, x: Int) => encodeAndThenDecodeProp(Person(s, x))))
|
||||
}
|
||||
|
||||
@Test def `a 'Contacts' value should be encoded as a JSON object (1pt)`(): Unit = {
|
||||
val contacts = Contacts(List(Person("Alice", 42)))
|
||||
val json = Json.Obj(Map("people" ->
|
||||
Json.Arr(List(Json.Obj(Map("name" -> Json.Str("Alice"), "age" -> Json.Num(42)))))
|
||||
))
|
||||
val encoder = summon[Encoder[Contacts]]
|
||||
assert(encoder.encode(contacts) == json)
|
||||
}
|
||||
|
||||
@Test def `it is possible to encode and decode contacts (4pts)`(): Unit = {
|
||||
val peopleGenerator = Gen.listOf(Gen.resultOf((s: String, x: Int) => Person(s, x)))
|
||||
checkProperty(Prop.forAll(peopleGenerator)(people => encodeAndThenDecodeProp(Contacts(people))))
|
||||
}
|
||||
|
||||
}
|
||||
|
||||
trait TestEncoders extends EncoderFallbackInstance
|
||||
|
||||
trait EncoderFallbackInstance {
|
||||
|
||||
given [A](given ct: ClassTag[A]): Encoder[A] = throw new AssertionError(s"No given instance of `Encoder[${ct.runtimeClass.getSimpleName}]`")
|
||||
|
||||
}
|
||||
|
||||
trait TestDecoders extends DecoderFallbackInstance
|
||||
|
||||
trait DecoderFallbackInstance {
|
||||
|
||||
given [A](given ct: ClassTag[A]): Decoder[A] = throw new AssertionError(s"No given instance of `Decoder[${ct.runtimeClass.getSimpleName}]")
|
||||
|
||||
}
|
||||
@ -1,9 +0,0 @@
|
||||
// Used for base64 encoding
|
||||
libraryDependencies += "commons-codec" % "commons-codec" % "1.10"
|
||||
|
||||
// Used for Coursera submussion
|
||||
// libraryDependencies += "org.scalaj" %% "scalaj-http" % "2.4.2"
|
||||
// libraryDependencies += "com.typesafe.play" %% "play-json" % "2.7.4"
|
||||
|
||||
// Student tasks (i.e. packageSubmission)
|
||||
enablePlugins(StudentTasks)
|
||||
Loading…
Reference in New Issue
Block a user