Initial commit with weather data fetcher and parser

src/main/scala/fetch/FetchData.scala

@@ -0,0 +1,51 @@
+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 {
+  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 val baseUrl = Uri.unsafeFromString("https://jsonplaceholder.typicode.com/") // todos/1
+
+  def saveToFile(fileName: String, content: String): IO[Unit] = {
+    val path = Paths.get(s"data/$fileName")
+    IO(Files.writeString(path, content)).attempt.flatMap {
+      case Right(_) => IO(println(s"write: $fileName"))
+      case Left(error) => IO(println(s"Write file '$fileName' failed with error: ${error.getMessage}"))
+    }
+  }
+
+  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) => saveToFile(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.generateLast5Hours()
+    //    fileNames.foreach(println)
+    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/FileName.scala

@@ -0,0 +1,40 @@
+package fetch
+
+import java.time.format.DateTimeFormatter
+import java.time.{LocalDateTime, Duration}
+
+object FileName {
+  private val interval = Duration.ofMinutes(30)
+  private val formatter = DateTimeFormatter.ofPattern("yyyyMMdd_HHmm")s
+
+  def generateLastHour(): List[String] = {
+    val now = LocalDateTime.now
+    generate(now.minusHours(1), now)
+  }
+
+  def generateLast5Hours(): List[String] = {
+    val now = roundToInterval(LocalDateTime.now, false)
+    generate(now.minusHours(5), now)
+  }
+
+  private def roundToInterval(time: LocalDateTime, roundUp: Boolean): LocalDateTime = {
+    val minutes = time.getMinute
+    val adjustment = if (roundUp) (interval.toMinutes - minutes % interval.toMinutes) % interval.toMinutes
+    else -minutes % interval.toMinutes
+
+    time.plusMinutes(adjustment)
+  }
+
+  // not sure either data are each 10 minutes or each 30 mins of hour
+  def generate(startTime: LocalDateTime, endTime: LocalDateTime): List[String] = {
+    val roundStartTime = roundToInterval(startTime, true)
+    val roundEndTime = roundToInterval(endTime, false)
+
+    Iterator.iterate(roundStartTime) { time =>
+      time.plus(interval)
+    }.takeWhile(!_.isAfter(roundEndTime))
+      .filter(_.getMinute == 30)
+      .map(time => s"${formatter.format(time)}.csv")
+      .toList
+  }
+}