时间戳

首页 > 解决方案 > Angular 11 Firebase 服务器端渲染无限加载/挂起

angular - Angular 11 Firebase 服务器端渲染无限加载/挂起

问题描述

我有一个 Angular 11 应用程序可以正常工作，即在非 SSR 模式下。这是一个查询 T 类型文档集合的示例（获取一次，不观察更改）。

在非 SSR 中工作的版本，查询集合的预期代码：

this.firestore.collection<T>('collection', ref => ref.limit(5))
    .get()
    .pipe(
      map((qs: firebase.firestore.QuerySnapshot) => qs.empty ? [] : qs.docs.map(d => d.data() as T)),
    );

当切换到 SSR 时，上面的代码会导致 express 服务器挂起，并且客户端会看到一个永远不会完成的“待处理”查询，或者遇到超时并导致页面部分呈现（即没有该查询的结果）。

我将 Angular 11 与 Ivy 一起使用。我的 package.json 中的相关条目：

{
  "dependencies": {
    "@angular/cdk": "^11.0.3",
    "@angular/common": "~11.0.5",
    "@angular/compiler": "~11.0.5",
    "@angular/core": "~11.0.5",
    "@angular/fire": "6.1.4",
    "@angular/flex-layout": "^11.0.0-beta.33",
    "@angular/forms": "~11.0.5",
    "@angular/material": "^11.0.3",
    "@angular/platform-browser": "~11.0.5",
    "@angular/platform-browser-dynamic": "~11.0.5",
    "@angular/platform-server": "~11.0.5",
    "@angular/router": "~11.0.5",
    "@nguniversal/express-engine": "^11.0.1",
    "bootstrap": "^4.5.2",
    "express": "^4.17.1",
    "firebase": "^8.2.1",
    "rxjs": "~6.6.3",
    "tslib": "^2.0.0",
    "zone.js": "~0.10.3"
  },
  "devDependencies": {
    "@angular-builders/custom-webpack": "^11.0.0-beta.4",
    "@angular-devkit/architect": "~0.1100.5",
    "@angular-devkit/build-angular": "~0.1100.5",
    "@angular/cli": "~11.0.5",
    "@angular/compiler-cli": "~11.0.5",
    "@nguniversal/builders": "^11.0.1",
    "@ngx-builders/analyze": "^2.0.0",
    "@types/express": "^4.17.0",
    "@types/node": "^12.11.1",
    "bufferutil": "^4.0.2",
    "firebase-tools": "^9.0.1",
    "ts-node": "~9.1.1",
    "typescript": "~4.0.5",
    "utf-8-validate": "^5.0.3",
    "ws": "^7.4.1",
    "xhr2": "^0.2.0"
  }
}

在 angular.json 的 server.options 字段中，我必须添加以下内容以减轻以下错误ENOENT: no such file or directory, open '.../dist/server/src/protos/google/firestore/v1/firestore.proto'

externalDependencies: [
              "@firebase/analytics",
              "@firebase/analytics-types",
              "@firebase/app",
              "@firebase/app-types",
              "@firebase/auth",
              "@firebase/auth-interop-types",
              "@firebase/auth-types",
              "@firebase/component",
              "@firebase/database",
              "@firebase/database-types",
              "@firebase/firestore",
              "@firebase/firestore-types",
              "@firebase/functions",
              "@firebase/functions-types",
              "@firebase/installations",
              "@firebase/installations-types",
              "@firebase/logger",
              "@firebase/messaging",
              "@firebase/messaging-types",
              "@firebase/performance",
              "@firebase/performance-types",
              "@firebase/polyfill",
              "@firebase/remote-config",
              "@firebase/remote-config-types",
              "@firebase/storage",
              "@firebase/storage-types",
              "@firebase/util",
              "@firebase/webchannel-wrapper"]

标签： angularfirebaseserver-side-renderingangular-universal

解决方案

经过很长时间的调试会话后，我将问题的根源缩小到问题中列出的 Firebase 查询。以下查询是一种解决方法，可以在不挂起的情况下呈现页面。

this.firestore.collection<T>('collection', ref => ref.limit(5))
    .valueChanges()   <<<<
    .pipe(
      take(2),        <<<<
    );

难以调试的一个方面是因为下面更健全的版本，它关闭了源 observable 导致服务器也挂起（记住，我不想观察变化，所以take(1)是有意义的） . 但是， Take(2)并没有挂起……这看起来像是堆栈中某处的错误，可能在 Firebase 中。

这将是更明智的解决方法......但会导致快速服务器挂起，给客户端留下一个pending请求：

this.firestore.collection<T>('collection', ref => ref.limit(5))
    .valueChanges()
    .pipe(
      take(1),      <<<<
    );

使用 Promise 也会导致挂起，所以我目前只剩下 valueChanges()+take(2) 解决方法。

推荐阅读