Limit all dates asking to 3 months range

src/main/scala/db/DBService.scala

@@ -81,6 +81,20 @@ class DBService(log: Logger[IO]) extends DataServiceTrait {
     } yield dates.sorted
   }
 
+  def getDatesByMonths(monthList: List[LocalDate]): IO[List[LocalDate]] = {
+    val dateFormatter = DateTimeFormatter.ofPattern("yyyyMMdd")
+    val monthFormatter = DateTimeFormatter.ofPattern("yyyyMM")
+    val monthStrList = monthList.map(_.format(monthFormatter))
+    for {
+      fileNames <- readFileNames(dataPath)
+      datesStr <- IO(fileNames.map(_.take(8)).distinct) // take yyyyMMdd
+      filteredDatesStr = datesStr.filter(date => monthStrList.contains(date.take(6)))
+      dates <- filteredDatesStr.traverse { str =>
+        IO(LocalDate.parse(str, dateFormatter)).option
+      }.map(_.flatten)
+    } yield dates.sorted
+  }
+
   def getDateFileNames(date: LocalDate): IO[List[String]] = {
     val formatter: DateTimeFormatter = DateTimeFormatter.ofPattern("yyyyMMdd")
     val dateStr: String = date.format(formatter)

src/main/scala/db/DataService.scala

@@ -63,6 +63,8 @@ class DataService private(
 
   def getDates: IO[List[LocalDate]] = dbService.getDates
 
+  def getDatesByMonths(monthList: List[LocalDate]): IO[List[LocalDate]] = dbService.getDatesByMonths(monthList)
+
   def getDateFileNames(date: LocalDate): IO[List[String]] = dbService.getDateFileNames(date)
 
   // TODO implement getting full data from state

src/main/scala/server/Server.scala

@@ -6,7 +6,7 @@ import com.comcast.ip4s.IpLiteralSyntax
 import db.DataService
 import fetch.FetchService
 import parse.{Aggregate, Parser, WeatherData}
-import server.ValidateRoutes.{AggKey, CityList, DateTimeRange, Granularity, ValidDate}
+import server.ValidateRoutes.{AggKey, CityList, DateTimeRange, Granularity, ValidDate, ValidateMonths}
 import io.circe.{Json, Printer}
 import org.http4s._
 import org.http4s.dsl.io._
@@ -89,6 +89,12 @@ class Server(dataService: DataService, fetch: FetchService, log: Logger[IO]) {
         Ok(dates.asJson.pretty)
       )
 
+    // http://0.0.0.0:8080/api/show/months/202304,202305,202306
+    case GET -> Root / "show" / "months" / ValidateMonths(monthList) =>
+      dataService.getDatesByMonths(monthList).flatMap(dates =>
+        Ok(dates.asJson.pretty)
+      )
+
     // http://0.0.0.0:8080/api/show/date/20230423
     case GET -> Root / "show" / "date" / ValidDate(date) =>
       dataService.getDateFileNames(date).flatMap(fileNames =>

src/main/scala/server/ValidateRoutes.scala

@@ -27,6 +27,21 @@ object ValidateRoutes {
     }
   }
 
+  object ValidateMonths {
+    def unapply(str: String): Option[List[LocalDate]] = {
+      val formatter = DateTimeFormatter.ofPattern("yyyyMMdd")
+      val monthList = str
+        .split(",")
+        .toList
+        .flatMap(str => Try(LocalDate.parse(str + "01", formatter)).toOption)
+
+      monthList match {
+        case Nil => None
+        case list => Some(list)
+      }
+    }
+  }
+
   object CityList {
     def unapply(str: String): Option[List[String]] = {
       str.split(",").toList match {

src/test/scala/db/DBServiceSpec.scala

@@ -34,6 +34,27 @@ class DBServiceSpec extends AnyFunSuite with Matchers {
     lines.length shouldBe 2142
   }
 
+  test("getDatesByMonths should return filtered dates") {
+    val monthFormatter = DateTimeFormatter.ofPattern("yyyyMMdd")
+    val monthList = List(
+      LocalDate.parse("20230401", monthFormatter),
+      LocalDate.parse("20230501", monthFormatter),
+      LocalDate.parse("20230601", monthFormatter),
+    )
+    val dbService = DBService.of.unsafeRunSync()
+    val dates = dbService.getDatesByMonths(monthList).unsafeRunSync()
+
+    dates should not be empty
+
+    val exportFormatter = DateTimeFormatter.ofPattern("yyyy-MM-dd")
+    val validPrefixes = Set("2023-04", "2023-05", "2023-06")
+    val invalidDates = dates
+      .map(_.format(exportFormatter))
+      .filterNot(date => validPrefixes.exists(prefix => date.startsWith(prefix)))
+
+    invalidDates shouldBe empty
+  }
+
   test("DBService.save should return correct result") {
     val dbService = DBService.of.unsafeRunSync()
     val fileName = "testFile.txt"

web/src/fileManager/Calendar.tsx

@@ -1,24 +1,31 @@
 import moment from "moment";
-import { Accessor, Component, createSignal, Setter } from "solid-js";
+import { Accessor, Component, Setter } from "solid-js";
 
 import "../css/calendar.css";
 
 export const Calendar: Component<{
     getSelectedDate: Accessor<Date>,
     setSelectedDate: Setter<Date>,
-    datesWithData: Date[],
+    setCurrentMonth: Setter<Date>,
-}> = ({getSelectedDate, setSelectedDate, datesWithData}) => {
+    datesWithData: () => Date[],
-    const dateStrArr = () => datesWithData.map(d => d.toDateString());
+}> = ({getSelectedDate, setSelectedDate, setCurrentMonth, datesWithData}) => {
+    const dateStrArr = () => datesWithData().map(d => d.toDateString());
+
+    function changeMonths(delta: number): void {
+        const newDate = moment(getSelectedDate()).add(delta, "months").toDate();
+        setCurrentMonth(newDate);
+        setSelectedDate(newDate);
+    }
 
     return (
         <div>
             <h3>Calendar</h3>
             <div class="calendar-top">
-                <button onClick={() => setSelectedDate(moment(getSelectedDate()).subtract(1, "months").toDate()) }>&lt;&lt;</button>
+                <button onClick={() => changeMonths(-1) }>&lt;&lt;</button>
                 <div class="calendar-year-month">
                     {moment(getSelectedDate()).format("YYYY, MMM")}
                 </div>
-                <button onclick={() => setSelectedDate(moment(getSelectedDate()).add(1, "months").toDate())}>&gt;&gt;</button>
+                <button onclick={() => changeMonths(1)}>&gt;&gt;</button>
             </div>
             <div class="calendar">
                 { getPaddedMonth(getSelectedDate()).map(d => {

web/src/fileManager/DateList.tsx

@@ -1,18 +1,26 @@
-import { Accessor, Component, createResource, Setter } from "solid-js";
+import moment from "moment";
+import { Accessor, Component, createResource, createSignal, Setter } from "solid-js";
+
 import { apiHost } from "../consts";
 
 import "../css/spinner.css";
 import { Calendar } from "./Calendar";
 
 export const DateList: Component<{getDate: Accessor<Date>, setDate: Setter<Date>;}> = (props) => {
+    const [getCurrentMonth, setCurrentMonth] = createSignal(new Date());
     const fetchDates = async () => {
+        const months = [
+            moment(getCurrentMonth()).format("yyyyMM"),
+            moment(getCurrentMonth()).subtract(1, "months").format("yyyyMM"),
+            moment(getCurrentMonth()).add(1, "months").format("yyyyMM"),
+        ];
         await new Promise(resolve => setTimeout(resolve, 500))
-        const response = await fetch(`${apiHost}/api/show/all_dates`);
+        const response = await fetch(`${apiHost}/api/show/months/${months.join(",")}`);
         const json = await response.json();
         return json;
     }
 
-    const [datesResource] = createResource(fetchDates);
+    const [datesResource] = createResource(getCurrentMonth, fetchDates);
 
     return (
         <div>
@@ -25,10 +33,11 @@ export const DateList: Component<{getDate: Accessor<Date>, setDate: Setter<Date>
             { datesResource.error && (
                 <div>Error while loading dates: ${datesResource.error}</div>
             )}
-            { datesResource() && <Calendar
+            { !datesResource.loading && datesResource() && <Calendar
                 getSelectedDate={props.getDate}
                 setSelectedDate={props.setDate}
-                datesWithData={datesResource().map((str: string) => new Date(str))}
+                setCurrentMonth={setCurrentMonth}
+                datesWithData={() => datesResource().map((str: string) => new Date(str))}
             /> }
             
             {/* Backup date view */}