From 1bb6447141551967dfde785df2fca79048ba62a5 Mon Sep 17 00:00:00 2001
From: Vasily Zubarev <me@vas3k.ru>
Date: Fri, 4 Apr 2025 13:49:51 +0200
Subject: [PATCH] feat: move currency converter to server

---
 app/api/currency/route.ts             | 66 +++++++++++++++++++++++++++
 components/forms/convert-currency.tsx | 22 ++++++++-
 lib/currency-scraper.ts               | 57 -----------------------
 3 files changed, 87 insertions(+), 58 deletions(-)
 create mode 100644 app/api/currency/route.ts
 delete mode 100644 lib/currency-scraper.ts

diff --git a/app/api/currency/route.ts b/app/api/currency/route.ts
new file mode 100644
index 0000000..a1af942
--- /dev/null
+++ b/app/api/currency/route.ts
@@ -0,0 +1,66 @@
+import { format } from "date-fns"
+import { NextRequest, NextResponse } from "next/server"
+
+type HistoricRate = {
+  currency: string
+  rate: number
+  inverse: number
+}
+
+export async function GET(request: NextRequest) {
+  try {
+    const searchParams = request.nextUrl.searchParams
+    const fromCurrency = searchParams.get("from")
+    const toCurrency = searchParams.get("to")
+    const dateParam = searchParams.get("date")
+
+    if (!fromCurrency || !toCurrency || !dateParam) {
+      return NextResponse.json({ error: "Missing required parameters: from, to, date" }, { status: 400 })
+    }
+
+    const date = new Date(dateParam)
+    if (isNaN(date.getTime())) {
+      return NextResponse.json({ error: "Invalid date format" }, { status: 400 })
+    }
+
+    const formattedDate = format(date, "yyyy-MM-dd")
+    const url = `https://www.xe.com/currencytables/?from=${fromCurrency}&date=${formattedDate}`
+
+    const response = await fetch(url)
+
+    if (!response.ok) {
+      return NextResponse.json(
+        { error: `Failed to fetch currency data: ${response.status}` },
+        { status: response.status }
+      )
+    }
+
+    const html = await response.text()
+
+    // Extract the JSON data from the __NEXT_DATA__ script tag
+    const scriptTagRegex = /<script id="__NEXT_DATA__" type="application\/json">([\s\S]*?)<\/script>/
+    const match = html.match(scriptTagRegex)
+
+    if (!match || !match[1]) {
+      return NextResponse.json({ error: "Could not find currency data in the page" }, { status: 500 })
+    }
+
+    const jsonData = JSON.parse(match[1])
+    const historicRates = jsonData.props.pageProps.historicRates as HistoricRate[]
+
+    if (!historicRates || historicRates.length === 0) {
+      return NextResponse.json({ error: "No currency rates found for the specified date" }, { status: 404 })
+    }
+
+    const rate = historicRates.find((rate) => rate.currency === toCurrency)
+
+    if (!rate) {
+      return NextResponse.json({ error: `Currency rate not found for ${toCurrency}` }, { status: 404 })
+    }
+
+    return NextResponse.json({ rate: rate.rate })
+  } catch (error) {
+    console.error("Currency API error:", error)
+    return NextResponse.json({ error: "Internal server error" }, { status: 500 })
+  }
+}
diff --git a/components/forms/convert-currency.tsx b/components/forms/convert-currency.tsx
index 60668a8..1153899 100644
--- a/components/forms/convert-currency.tsx
+++ b/components/forms/convert-currency.tsx
@@ -1,4 +1,3 @@
-import { getCurrencyRate } from "@/lib/currency-scraper"
 import { formatCurrency } from "@/lib/utils"
 import { format, startOfDay } from "date-fns"
 import { Loader2 } from "lucide-react"
@@ -75,3 +74,24 @@ export const FormConvertCurrency = ({
     </div>
   )
 }
+
+async function getCurrencyRate(currencyCodeFrom: string, currencyCodeTo: string, date: Date): Promise<number> {
+  try {
+    const formattedDate = format(date, "yyyy-MM-dd")
+    const url = `/api/currency?from=${currencyCodeFrom}&to=${currencyCodeTo}&date=${formattedDate}`
+
+    const response = await fetch(url)
+
+    if (!response.ok) {
+      const errorData = await response.json()
+      console.error("Currency API error:", errorData.error)
+      return 0
+    }
+
+    const data = await response.json()
+    return data.rate
+  } catch (error) {
+    console.error("Error fetching currency rate:", error)
+    return 0
+  }
+}
diff --git a/lib/currency-scraper.ts b/lib/currency-scraper.ts
deleted file mode 100644
index 4b2712a..0000000
--- a/lib/currency-scraper.ts
+++ /dev/null
@@ -1,57 +0,0 @@
-import { format } from "date-fns"
-
-type HistoricRate = {
-  currency: string
-  rate: number
-  inverse: number
-}
-
-export async function getCurrencyRate(currencyCodeFrom: string, currencyCodeTo: string, date: Date): Promise<number> {
-  const rates = await fetchHistoricalCurrencyRates(currencyCodeFrom, date)
-
-  if (!rates || rates.length === 0) {
-    console.log("Could not fetch currency rates", currencyCodeFrom, currencyCodeTo, date)
-    return 0
-  }
-
-  const rate = rates.find((rate) => rate.currency === currencyCodeTo)
-
-  if (!rate) {
-    console.log("Could not find currency rate", currencyCodeFrom, currencyCodeTo, date)
-    return 0
-  }
-
-  return rate.rate
-}
-
-export async function fetchHistoricalCurrencyRates(currency: string = "USD", date: Date): Promise<HistoricRate[]> {
-  const formattedDate = format(date, "yyyy-MM-dd")
-
-  const url = `https://corsproxy.io/?url=${encodeURIComponent(
-    `https://www.xe.com/currencytables/?from=${currency}&date=${formattedDate}`
-  )}`
-
-  const response = await fetch(url)
-
-  if (!response.ok) {
-    throw new Error(`HTTP error! Status: ${response.status}`)
-  }
-
-  const html = await response.text()
-
-  // Extract the JSON data from the __NEXT_DATA__ script tag
-  const scriptTagRegex = /<script id="__NEXT_DATA__" type="application\/json">([\s\S]*?)<\/script>/
-  const match = html.match(scriptTagRegex)
-
-  if (!match || !match[1]) {
-    throw new Error("Could not find currency data in the page")
-  }
-
-  const jsonData = JSON.parse(match[1])
-
-  const historicRates = jsonData.props.pageProps.historicRates as HistoricRate[]
-
-  console.log("Historic Rates for this date", historicRates)
-
-  return historicRates
-}