feat: single flight for repo and avatar request

xhofe · Sep 22, 2024 · c158535 · c158535
1 parent 53cd67e
commit c158535
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Showing 4 changed files with 73 additions and 5 deletions.
diff --git a/app/(empty)/iframe/layout.tsx b/app/(empty)/iframe/layout.tsx
@@ -4,8 +4,8 @@ export default function RootLayout({
   children: React.ReactNode
 }) {
   return (
-    <html lang="en" className="h-full">
-      <body className="h-full">{children}</body>
+    <html lang="en" className="h-full bg-transparent">
+      <body className="h-full bg-transparent">{children}</body>
     </html>
   )
 }
diff --git a/app/api/github.ts b/app/api/github.ts
@@ -2,7 +2,7 @@ import { LRUCache } from "lru-cache"
 import { GhUser, GhUserUse } from "./types"
 import fs from "node:fs/promises"
 import path from "node:path"
-import { throttle } from "@/utils"
+import { throttle, Singleflight } from "@/utils"
 
 const repoCache = new LRUCache<string, GhUserUse[]>({
   max: 500,
@@ -90,6 +90,9 @@ export function usedBy(per_page: number, page: number) {
   }
 }
 
+const repoSF = new Singleflight()
+const avatarSF = new Singleflight()
+
 async function fetchRepoOnePage(repo: string, page: number) {
   const cacheKey = `${repo}-${page}`
   if (repoCache.has(cacheKey)) {
@@ -158,7 +161,7 @@ export async function fetchRepos(repos: string[], maxPages?: number) {
   const users = (
     await Promise.all(
       repos.map(async (repo) => {
-        const users = await fetchRepo(repo, maxPages)
+        const users = await repoSF.do(repo, () => fetchRepo(repo, maxPages))
         return users
       })
     )
@@ -174,7 +177,7 @@ export async function fetchAvatar(url: string) {
   if (avatarCache.has(url)) {
     return avatarCache.get(url)!
   }
-  const response = await fetch(url)
+  const response = await avatarSF.do(url, () => fetch(url))
   const res = Buffer.from(await response.arrayBuffer())
   avatarCache.set(url, res)
   return res

diff --git a/utils/index.ts b/utils/index.ts
@@ -1,3 +1,4 @@
 export * from "./fetch"
 export * from "./svg"
 export * from "./func"
+export * from "./single-flight"
diff --git a/utils/single-flight.ts b/utils/single-flight.ts
@@ -0,0 +1,64 @@
+export type Fn<T = any> = () => T | Promise<T>
+export type ResolveFn = (res: any) => void
+
+export type KeyType = string | symbol
+
+export interface Call {
+  resolveFns: ResolveFn[]
+  rejectFns: ResolveFn[]
+}
+
+let resolveInstance: Promise<void>
+
+export class Singleflight {
+  private singleFlightQueue = new Map<KeyType, Call>()
+
+  async do<T = any>(key: KeyType, fn: Fn<T>): Promise<T> {
+    const [res] = await this.doWithFresh(key, fn)
+    return res
+  }
+
+  async doWithFresh<T = any>(
+    key: KeyType,
+    fn: Fn<T>
+  ): Promise<[data: T, fresh: boolean]> {
+    const promise: Promise<[data: T, fresh: boolean]> = new Promise(
+      (resolve, reject) => {
+        const call: Call = this.singleFlightQueue.get(key) || {
+          resolveFns: [],
+          rejectFns: [],
+        }
+
+        call.resolveFns.push(resolve)
+        call.rejectFns.push(reject)
+        this.singleFlightQueue.set(key, call)
+        if (call.resolveFns.length === 1) {
+          if (!resolveInstance) {
+            resolveInstance = Promise.resolve()
+          }
+          // ensure always work even fn is sync function
+          resolveInstance
+            .then(() => fn())
+            .then((res) => {
+              const waitCall = this.singleFlightQueue.get(key)!
+              waitCall.resolveFns.forEach((resolve, i) => {
+                if (i === 0) {
+                  resolve([res, true])
+                } else {
+                  resolve([res, false])
+                }
+              })
+              this.singleFlightQueue.delete(key)
+            })
+            .catch((err) => {
+              const waitCall = this.singleFlightQueue.get(key)!
+              waitCall.rejectFns.forEach((reject) => reject(err))
+              this.singleFlightQueue.delete(key)
+            })
+        }
+      }
+    )
+
+    return promise
+  }
+}