Server fetches and saves files. Also proper error handling

src/main/scala/db/DBService.scala

@@ -6,7 +6,7 @@ import cats.implicits.toTraverseOps
 
 import java.io.File
 import java.nio.file.{Files, Paths}
-import java.time.LocalDateTime
+import java.time.{LocalDate, LocalDateTime}
 import java.time.format.DateTimeFormatter
 import scala.io.Source
 import scala.util.Try
@@ -46,19 +46,35 @@ object DBService {
     } yield fileLines.flatten
   }
 
-  def save(fileName: String, content: String): IO[Unit] = {
+  def save(fileName: String, content: String): IO[Either[Throwable, String]] = {
     val path = Paths.get(s"$dataPath/$fileName")
-    // TODO redeemWith instead of flatMap
+    IO(Files.writeString(path, content))
-    IO(Files.writeString(path, content)).attempt.flatMap {
+      .redeemWith(
-      case Right(_) => IO.println(s"write: $fileName")
+        error => IO(Left(error))
-      case Left(error) => IO.println(s"Write file '$fileName' failed with error: ${error.getMessage}")
+//          .flatTap(_ => IO.println(s"Write file '$fileName' failed with error: ${error.getMessage}"))
+        ,
+        _ => IO(Right(fileName))
+//          .flatTap(_ => IO.println(s"write: $fileName"))
+      )
   }
+
+  def getDates(): IO[Set[LocalDate]] = {
+    val formatter = DateTimeFormatter.ofPattern("yyyyMMdd")
+    for {
+      fileNames <- readFileNames(dataPath)
+      datesStr <- IO.pure(fileNames.map(_.take(8)).toSet)
+      dates <- IO.pure(datesStr.flatMap(str => {
+        Try(LocalDate.parse(str, formatter)).toOption
+      }))
+    } yield dates
+  }
+
+  def fetchDates(date: LocalDate): IO[List[String]] = {
+    ???
   }
 
   // TODO remove this. Just testing
-  private def run: IO[Unit] = {
+  private def testGetInRange: IO[Unit] = {
-    println("----------------> db main")
-
     val from = LocalDateTime.parse("20230414_2200", dateFormatter)
     val to = LocalDateTime.parse("20230501_1230", dateFormatter)
 
@@ -68,7 +84,16 @@ object DBService {
     } yield ()
   }
 
+  private def testGetDates: IO[Unit] = {
+    for {
+      dates <- getDates()
+      _ <- IO.println(dates)
+    } yield ()
+  }
+
   def main(args: Array[String]): Unit = {
-    run.unsafeRunSync()
+    println("----------------> db main")
+//    testGetInRange.unsafeRunSync()
+    testGetDates.unsafeRunSync()
   }
 }

src/main/scala/fetch/FetchData.scala

@@ -1,42 +0,0 @@
-package fetch
-
-import cats.effect._
-import cats.implicits._
-import org.http4s._
-import org.http4s.blaze.client.BlazeClientBuilder
-import org.http4s.client.Client
-import org.http4s.headers.Authorization
-
-import com.typesafe.config.ConfigFactory
-
-import java.nio.file.{Files, Paths}
-import scala.concurrent.ExecutionContext.global
-
-object FetchData extends IOApp.Simple {
-  // TODO wrap config in IO
-  private val config = ConfigFactory.load()
-  private val basicCredentials = BasicCredentials(config.getString("username"), config.getString("password"))
-  private val baseUrl = Uri.unsafeFromString(config.getString("url")) // 20220831_1330.csv
-
-  def makeRequest(client: Client[IO], url: Uri): IO[Unit] = {
-    val fileName = url.path.toString()
-    for {
-      request <- Request[IO](Method.GET, url)
-        .withHeaders(Authorization(basicCredentials))
-        .pure[IO]
-      responseOrError <- client.expect[String](request).attempt
-      _ <- responseOrError match {
-        case Right(response) => db.DBService.save(fileName, response)
-        case Left(error) => IO(println(s"Request failed to url: $url with error: ${error.getMessage}"))
-      }
-    } yield ()
-  }
-
-  def run: IO[Unit] = {
-    val fileNames = FileName.generateLastNHours(10)
-    val urls = fileNames.map(baseUrl / _)
-    BlazeClientBuilder[IO](global).resource.use { client =>
-      urls.traverse(url => makeRequest(client, url)) // urls.map(...).sequence
-    }
-  }.as(ExitCode.Success)
-}

src/main/scala/fetch/FetchService.scala

@@ -0,0 +1,52 @@
+package fetch
+
+import cats.effect._
+import cats.implicits._
+import org.http4s._
+import org.http4s.blaze.client.BlazeClientBuilder
+import org.http4s.client.Client
+import org.http4s.headers.Authorization
+import com.typesafe.config.ConfigFactory
+
+import java.time.{LocalDate, LocalDateTime}
+import scala.concurrent.ExecutionContext.global
+
+object FetchService {
+  // TODO wrap config in IO
+  private val config = ConfigFactory.load()
+  private val basicCredentials = BasicCredentials(config.getString("username"), config.getString("password"))
+  private val baseUrl = Uri.unsafeFromString(config.getString("url")) // 20220831_1330.csv
+
+  private def makeRequest(client: Client[IO], url: Uri): IO[Either[Throwable, (String, String)]] = {
+    val fileName = url.path.toString()
+    for {
+      request <- Request[IO](Method.GET, url)
+        .withHeaders(Authorization(basicCredentials))
+        .pure[IO]
+      result <- client.expect[String](request).redeemWith(
+        error => IO(Left(error))
+//          .flatTap(_ => IO.println(s"Request failed to url: $url with error: ${error.getMessage}"))
+        ,
+        fileContent => IO(Right((fileName, fileContent)))
+//          .flatTap(_ => IO.println(s"Fetched: $fileName"))
+      )
+    } yield result
+  }
+
+  private def fetchFiles(fileNames: List[String]): IO[List[Either[Throwable, (String, String)]]] = {
+    val urls = fileNames.map(baseUrl / _)
+    BlazeClientBuilder[IO](global).resource.use { client =>
+      urls.traverse(url => makeRequest(client, url))
+    }
+  }
+
+  def fetchInRange(from: LocalDateTime, to: LocalDateTime): IO[List[Either[Throwable, (String, String)]]] = {
+    val fileNames = FileNameService.generate(from, to)
+    fetchFiles(fileNames)
+  }
+
+  def fetchFromDate(date: LocalDate): IO[List[Either[Throwable, (String, String)]]] = {
+    val fileNames = FileNameService.generateFromDate(date)
+    fetchFiles(fileNames)
+  }
+}

src/main/scala/fetch/FileNameService.scala

@@ -1,24 +1,24 @@
 package fetch
 
 import java.time.format.DateTimeFormatter
-import java.time.{LocalDateTime, Duration}
+import java.time.{Duration, LocalDate, LocalDateTime}
 
-object FileName {
+object FileNameService {
   private val interval = Duration.ofMinutes(30)
   private val formatter = DateTimeFormatter.ofPattern("yyyyMMdd_HHmm")
 
-  def generateLastHour(): List[String] = {
-    // TODO IO.timer() IOTimer
-    val now = LocalDateTime.now
-    generate(now.minusHours(1), now)
-  }
-
   // TODO side effect
   def generateLastNHours(hours: Int, now: LocalDateTime = LocalDateTime.now): List[String] = {
     val roundNow = roundToInterval(now, false)
     generate(roundNow.minusHours(hours), roundNow)
   }
 
+  def generateFromDate(date: LocalDate): List[String] = {
+    val from = LocalDateTime.of(date.getYear, date.getMonth, date.getDayOfMonth, 0, 0)
+    val to = LocalDateTime.of(date.getYear, date.getMonth, date.getDayOfMonth, 23, 59)
+    generate(from, to)
+  }
+
   private def roundToInterval(time: LocalDateTime, roundUp: Boolean): LocalDateTime = {
     val minutes = time.getMinute
     val adjustment = if (roundUp) (interval.toMinutes - minutes % interval.toMinutes) % interval.toMinutes

src/main/scala/fetch/Main.scala

@@ -0,0 +1,27 @@
+package fetch
+
+import cats.effect.IO
+import cats.effect.unsafe.implicits.global
+import cats.implicits.toTraverseOps
+import db.DBService
+
+import java.time.{LocalDate, LocalDateTime}
+
+object Main {
+  def run: IO[Unit] = {
+    val from = LocalDateTime.of(2023, 4, 23, 20, 0)
+    val to = LocalDateTime.of(2023, 4, 23, 23, 30)
+    for {
+      fetched <- FetchService.fetchInRange(from, to)
+//      fetched <- FetchService.fetchFromDate(LocalDate.of(2023, 4, 23))
+      (errors, successfulDownloads) = fetched.partitionMap(identity)
+      _ <- IO.println(s"Fetch errors: $errors")
+      saveResults <- successfulDownloads.traverse { case (name, content) => DBService.save(name, content) }
+      _ <- IO.println(s"Save results: $saveResults")
+    } yield ()
+  }
+
+  def main(args: Array[String]): Unit = {
+    run.unsafeRunSync()
+  }
+}

src/main/scala/server/Server.scala

@@ -1,14 +1,21 @@
 package server
 
 import cats.effect._
+import cats.implicits.toTraverseOps
+import db.DBService
+import fetch.FetchService
+import io.circe.{Json, Printer}
 import org.http4s._
 import org.http4s.dsl.io._
 import org.http4s.implicits._
 import org.http4s.server.Router
 import org.http4s.server.blaze.BlazeServerBuilder
+import io.circe.syntax._
+import io.circe.generic.auto._
+import org.http4s.circe.jsonEncoder
 import parse.{Meteo, Parser}
 
-import java.time.LocalDateTime
+import java.time.{LocalDate, LocalDateTime}
 import java.time.format.DateTimeFormatter
 import scala.util.Try
 
@@ -45,8 +52,34 @@ object Server extends IOApp {
         case _ => BadRequest(s"Invalid request format")
       }
 
-    case GET -> Root / "fetch" / dateRange =>
+    // http://localhost:3000/fetchDate/20230423
-      ???
+    case GET -> Root / "fetchDate" / dateStr => {
+      val dateFormatter = DateTimeFormatter.ofPattern("yyyyMMdd")
+      val maybeDate = Try(LocalDate.parse(dateStr, dateFormatter)).toEither
+      maybeDate match {
+        case Right(date) => {
+          val result = for {
+            fetched <- FetchService.fetchFromDate(date)
+            (fetchErrors, successDownloads) = fetched.partitionMap(identity)
+            saved <- successDownloads.traverse { case (name, content) => DBService.save(name, content) }
+            (saveErrors, successSaves) = saved.partitionMap(identity)
+            successes = successDownloads.map(s => s"fetched: ${s._1}") ++ successSaves.map(s => s"saved: $s")
+            errors = fetchErrors.map(e => s"FetchError: ${e.getMessage}") ++ saveErrors.map(e => s"SaveError: ${e.getMessage}")
+          } yield (successes, errors)
+
+          result.flatMap { case (successes, errors) =>
+            val responseBody = Json.obj(
+              "errors" -> errors.asJson,
+              "successes" -> successes.asJson
+            )
+            val printer = Printer.spaces2.copy(dropNullValues = true)
+            val prettyJson = printer.print(responseBody)
+            Ok(prettyJson)
+          }
+        }
+        case Left(_) => BadRequest("Invalid request format")
+      }
+    }
 
     case GET -> Root / "show" / "fetched_dates" =>
       ???