问题描述

使用NodeJS的后端应用，开发一个Mobile App的服务端，手机端通过REST API来访问获取后端数据。在本地编译好后，通过npm start启动项目，访问效果如下:

image

但是，当把项目文件通过FTP，或者直接VS Code 部署到App Service for windows后，访问首页并不是mobile app的页面，而是默认的App Service页面，访问项目里面的API也是404错误？

image

问题解决

从访问默认URL和测试API为404的效果来看，这是NodeJS项目并没有启动。因为是App Service For Windows环境，非ASP.NET的项目都需要通过IIS启用对于的进程文件来执行代码。如NodeJS项目则会启动一个 node.exe 用于执行 js 文件。

所以第一步是进入到App Service的高级工具 (Kudu）站点中，查看以下图片中的两点：

1： node.exe 进程是否存在

2： node.exe 进程中所加载的js文件是否是正确的启动文件

image

如果缺少了Web.config文件，则以下面的内容来创建它：

<?xml version="1.0" encoding="utf-8"?>
<!-- This configuration file is required if iisnode is used to run node processes behind
     IIS or IIS Express.  For more information, visit:

     https://github.com/tjanczuk/iisnode/blob/master/src/samples/configuration/web.config -->

<configuration>
  <system.webServer>
    <!-- Visit http://blogs.msdn.com/b/windowsazure/archive/2013/11/14/introduction-to-websockets-on-windows-azure-web-sites.aspx for more information on WebSocket support -->
    <webSocket enabled="false" />
    <handlers>
      <!-- Indicates that the server.js file is a node.js site to be handled by the iisnode module -->
      <add name="iisnode" path="app.js" verb="*" modules="iisnode"/>
    </handlers>

       <rewrite>
      <rules>
        <!-- Do not interfere with requests for node-inspector debugging -->
        <rule name="NodeInspector" patternSyntax="ECMAScript" stopProcessing="true">
          <match url="^app.js\/debug[\/]?" />
        </rule>

        <!-- First we consider whether the incoming URL matches a physical file in the /public folder -->
        <rule name="StaticContent">
          <action type="Rewrite" url="public{REQUEST_URI}"/>
        </rule>

        <!-- All other URLs are mapped to the node.js site entry point -->
        <rule name="DynamicContent">
          <conditions>
            <add input="{REQUEST_FILENAME}" matchType="IsFile" negate="True"/>
          </conditions>
          <action type="Rewrite" url="app.js"/>
        </rule>
      </rules>
    </rewrite>

    <!-- 'bin' directory has no special meaning in node.js and apps can be placed in it -->
    <security>
      <requestFiltering>
        <hiddenSegments>
          <remove segment="bin"/>
        </hiddenSegments>
      </requestFiltering>
    </security>

    <!-- Make sure error responses are left untouched -->
    <httpErrors existingResponse="PassThrough" />

    <!-- You can control how Node is hosted within IIS using the following options:
        * watchedFiles: semi-colon separated list of files that will be watched for changes to restart the server
        * node_env: will be propagated to node as NODE_ENV environment variable
        * debuggingEnabled - controls whether the built-in debugger is enabled
      See https://github.com/tjanczuk/iisnode/blob/master/src/samples/configuration/web.config for a full list of options -->
    <!--<iisnode watchedFiles="web.config;*.js"/>-->
  </system.webServer>
</configuration>

**PS: **handlers 和 rewrite 部分是必须的，其中 app.js 的名称可以根据实际项目中的启动文件而修改。

当web.config添加后，问题解决，再次访问效果为：

image

附录一：如果是遇见的其他错误，如 Module 缺少，则可以在 Logfiles中的 Application 文件夹中的 logging-errors.txt 中查看详细错误，如：

Mon Jan 24 2022 10:59:28 GMT+0000 (Greenwich Mean Time): Application has thrown an uncaught exception and is terminated:
Error: Cannot find module 'express'
Require stack:
- D:\home\site\wwwroot\index.js
- D:\Program Files (x86)\iisnode\interceptor.js
    at Function.Module._resolveFilename (internal/modules/cjs/loader.js:815:15)
    at Function.Module._load (internal/modules/cjs/loader.js:667:27)
    at Module.require (internal/modules/cjs/loader.js:887:19)
    at require (internal/modules/cjs/helpers.js:74:18)
    at Object.<anonymous> (D:\home\site\wwwroot\index.js:1:17)
    at Module._compile (internal/modules/cjs/loader.js:999:30)
    at Object.Module._extensions..js (internal/modules/cjs/loader.js:1027:10)
    at Module.load (internal/modules/cjs/loader.js:863:32)
    at Function.Module._load (internal/modules/cjs/loader.js:708:14)
    at Module.require (internal/modules/cjs/loader.js:887:19)
Mon Jan 24 2022 11:09:37 GMT+0000 (Greenwich Mean Time): Application has thrown an uncaught exception and is terminated:
Error: Cannot find module 'depd'
Require stack:
- D:\home\site\wwwroot\node_modules\body-parser\index.js
- D:\home\site\wwwroot\node_modules\express\lib\express.js
- D:\home\site\wwwroot\node_modules\express\index.js
- D:\home\site\wwwroot\index.js
- D:\Program Files (x86)\iisnode\interceptor.js
    at Function.Module._resolveFilename (internal/modules/cjs/loader.js:815:15)
    at Function.Module._load (internal/modules/cjs/loader.js:667:27)
    at Module.require (internal/modules/cjs/loader.js:887:19)
    at require (internal/modules/cjs/helpers.js:74:18)
    at Object.<anonymous> (D:\home\site\wwwroot\node_modules\body-parser\index.js:14:17)
    at Module._compile (internal/modules/cjs/loader.js:999:30)
    at Object.Module._extensions..js (internal/modules/cjs/loader.js:1027:10)
    at Module.load (internal/modules/cjs/loader.js:863:32)
    at Function.Module._load (internal/modules/cjs/loader.js:708:14)
    at Module.require (internal/modules/cjs/loader.js:887:19)
Mon Jan 24 2022 11:10:24 GMT+0000 (Greenwich Mean Time): Application has thrown an uncaught exception and is terminated:
Error: Cannot find module 'merge-descriptors'
Require stack:
- D:\home\site\wwwroot\node_modules\express\lib\express.js
- D:\home\site\wwwroot\node_modules\express\index.js
- D:\home\site\wwwroot\index.js
- D:\Program Files (x86)\iisnode\interceptor.js
    at Function.Module._resolveFilename (internal/modules/cjs/loader.js:815:15)
    at Function.Module._load (internal/modules/cjs/loader.js:667:27)
    at Module.require (internal/modules/cjs/loader.js:887:19)
    at require (internal/modules/cjs/helpers.js:74:18)
    at Object.<anonymous> (D:\home\site\wwwroot\node_modules\express\lib\express.js:17:13)
    at Module._compile (internal/modules/cjs/loader.js:999:30)
    at Object.Module._extensions..js (internal/modules/cjs/loader.js:1027:10)
    at Module.load (internal/modules/cjs/loader.js:863:32)
    at Function.Module._load (internal/modules/cjs/loader.js:708:14)
    at Module.require (internal/modules/cjs/loader.js:887:19)
Mon Jan 24 2022 11:11:35 GMT+0000 (Greenwich Mean Time): Application has thrown an uncaught exception and is terminated:
Error: Cannot find module 'finalhandler'
Require stack:
- D:\home\site\wwwroot\node_modules\express\lib\application.js
- D:\home\site\wwwroot\node_modules\express\lib\express.js
- D:\home\site\wwwroot\node_modules\express\index.js
- D:\home\site\wwwroot\index.js
- D:\Program Files (x86)\iisnode\interceptor.js
    at Function.Module._resolveFilename (internal/modules/cjs/loader.js:815:15)
    at Function.Module._load (internal/modules/cjs/loader.js:667:27)
    at Module.require (internal/modules/cjs/loader.js:887:19)
    at require (internal/modules/cjs/helpers.js:74:18)
    at Object.<anonymous> (D:\home\site\wwwroot\node_modules\express\lib\application.js:16:20)
    at Module._compile (internal/modules/cjs/loader.js:999:30)
    at Object.Module._extensions..js (internal/modules/cjs/loader.js:1027:10)
    at Module.load (internal/modules/cjs/loader.js:863:32)
    at Function.Module._load (internal/modules/cjs/loader.js:708:14)
    at Module.require (internal/modules/cjs/loader.js:887:19)

然后，直接从本地项目文件夹 node_modules 中的内容 上传到 App Service 中，即可解决 connot find module ‘ **** ’ 错误。

附录二：示例代码

下载地址：https://files.cnblogs.com/files/lulight/nodejs-express-azuermobileapp-web.confg.zip?t=1643031258

参考资料

Create a Node.js web app in Azure：https://docs.microsoft.com/en-us/azure/app-service/quickstart-nodejs?tabs=windows&pivots=development-environment-vscode

Node.js Hello World in App Service: https://github.com/Azure-Samples/nodejs-docs-hello-world

当在复杂的环境中面临问题，格物之道需：浊而静之徐清，安以动之徐生。 云中，恰是如此!

分类: 【Azure 应用服务】

标签: App Service, nodejs web.config, NodeJS + Express, 解决node.js的404问题