🧹 [コードの健全性向上] Dashboard APIルートの共通処理をリファクタリング

src/app/api/dashboard/stats/route.ts

@@ -1,31 +1,25 @@
 import { NextRequest, NextResponse } from "next/server";
-import { getServerSession } from "next-auth";
+import { getAuthenticatedUser, handleErrorResponse } from "@/lib/apiUtils";
 
-import { authOptions } from "@/lib/auth";
-import { fetchViewerLogin } from "@/lib/githubViewer";
 import { fetchCommitActivityHeatmap } from "@/lib/githubYearInReview";
 
 export async function GET(request: NextRequest) {
-    const session = await getServerSession(authOptions);
-    const token = session?.accessToken;
+    try {
+        const user = await getAuthenticatedUser();
+        if (!user) {
+            return NextResponse.json({ error: "Unauthorized" }, { status: 401 });
+        }
 
-    if (!session || !token) {
-        return NextResponse.json({ error: "Unauthorized" }, { status: 401 });
-    }
+        const yearParam = request.nextUrl.searchParams.get("year");
+        const year = yearParam ? Number.parseInt(yearParam, 10) : new Date().getUTCFullYear();
 
-    const yearParam = request.nextUrl.searchParams.get("year");
-    const year = yearParam ? Number.parseInt(yearParam, 10) : new Date().getUTCFullYear();
+        if (!Number.isFinite(year) || year < 2008 || year > new Date().getUTCFullYear()) {
+            return NextResponse.json({ error: "Invalid year" }, { status: 400 });
+        }
 
-    if (!Number.isFinite(year) || year < 2008 || year > new Date().getUTCFullYear()) {
-        return NextResponse.json({ error: "Invalid year" }, { status: 400 });
-    }
-
-    try {
-        const username = session.user?.login ?? (await fetchViewerLogin(token));
-        const heatmap = await fetchCommitActivityHeatmap(username, year, token);
+        const heatmap = await fetchCommitActivityHeatmap(user.username, year, user.token);
         return NextResponse.json({ year, heatmap });
     } catch (error) {
-        const message = error instanceof Error ? error.message : "Unknown error";
-        return NextResponse.json({ error: message }, { status: 500 });
+        return handleErrorResponse(error);
     }
 }

src/app/api/dashboard/summary/route.ts

@@ -1,24 +1,18 @@
 import { NextResponse } from "next/server";
-import { getServerSession } from "next-auth";
+import { getAuthenticatedUser, handleErrorResponse } from "@/lib/apiUtils";
 
-import { authOptions } from "@/lib/auth";
 import { fetchUserSummary } from "@/lib/github";
-import { fetchViewerLogin } from "@/lib/githubViewer";
 
 export async function GET() {
-    const session = await getServerSession(authOptions);
-    const token = session?.accessToken;
-
-    if (!session || !token) {
-        return NextResponse.json({ error: "Unauthorized" }, { status: 401 });
-    }
-
     try {
-        const username = session.user?.login ?? (await fetchViewerLogin(token));
-        const summary = await fetchUserSummary(username, token);
-        return NextResponse.json({ username, summary });
+        const user = await getAuthenticatedUser();
+        if (!user) {
+            return NextResponse.json({ error: "Unauthorized" }, { status: 401 });
+        }
+
+        const summary = await fetchUserSummary(user.username, user.token);
+        return NextResponse.json({ username: user.username, summary });
     } catch (error) {
-        const message = error instanceof Error ? error.message : "Unknown error";
-        return NextResponse.json({ error: message }, { status: 500 });
+        return handleErrorResponse(error);
     }
 }

src/app/api/dashboard/year/route.ts

@@ -1,31 +1,25 @@
 import { NextRequest, NextResponse } from "next/server";
-import { getServerSession } from "next-auth";
+import { getAuthenticatedUser, handleErrorResponse } from "@/lib/apiUtils";
 
-import { authOptions } from "@/lib/auth";
-import { fetchViewerLogin } from "@/lib/githubViewer";
 import { fetchYearInReviewData } from "@/lib/githubYearInReview";
 
 export async function GET(request: NextRequest) {
-    const session = await getServerSession(authOptions);
-    const token = session?.accessToken;
+    try {
+        const user = await getAuthenticatedUser();
+        if (!user) {
+            return NextResponse.json({ error: "Unauthorized" }, { status: 401 });
+        }
 
-    if (!session || !token) {
-        return NextResponse.json({ error: "Unauthorized" }, { status: 401 });
-    }
+        const yearParam = request.nextUrl.searchParams.get("year");
+        const year = yearParam ? Number.parseInt(yearParam, 10) : new Date().getUTCFullYear();
 
-    const yearParam = request.nextUrl.searchParams.get("year");
-    const year = yearParam ? Number.parseInt(yearParam, 10) : new Date().getUTCFullYear();
+        if (!Number.isFinite(year) || year < 2008 || year > new Date().getUTCFullYear()) {
+            return NextResponse.json({ error: "Invalid year" }, { status: 400 });
+        }
 
-    if (!Number.isFinite(year) || year < 2008 || year > new Date().getUTCFullYear()) {
-        return NextResponse.json({ error: "Invalid year" }, { status: 400 });
-    }
-
-    try {
-        const username = session.user?.login ?? (await fetchViewerLogin(token));
-        const data = await fetchYearInReviewData(username, year, token);
+        const data = await fetchYearInReviewData(user.username, year, user.token);
         return NextResponse.json(data);
     } catch (error) {
-        const message = error instanceof Error ? error.message : "Unknown error";
-        return NextResponse.json({ error: message }, { status: 500 });
+        return handleErrorResponse(error);
     }
 }

src/lib/apiUtils.ts

@@ -0,0 +1,21 @@
+import { NextResponse } from "next/server";
+import { getServerSession } from "next-auth";
+import { authOptions } from "@/lib/auth";
+import { fetchViewerLogin } from "@/lib/githubViewer";
+
+export async function getAuthenticatedUser() {
+    const session = await getServerSession(authOptions);
+    const token = session?.accessToken;
+
+    if (!session || !token) {
+        return null;
+    }
+
+    const username = session.user?.login ?? (await fetchViewerLogin(token));
+    return { username, token };
+}
+
+export function handleErrorResponse(error: unknown) {
+    const message = error instanceof Error ? error.message : "Unknown error";
+    return NextResponse.json({ error: message }, { status: 500 });
+}