找不到模块googleapis

这是我的代码:

var http = require('http');
var express = require('express');
var Session = require('express-session');
var google = require('googleapis');
var plus = google.plus('v1');
var OAuth2 = google.auth.OAuth2;

Error: Cannot find module 'googleapis'
    at Function.Module._resolveFilename (module.js:485:15)
    at Function.Module._load (module.js:437:25)
    at Module.require (module.js:513:17)
    at require (internal/module.js:11:18)
    at Object.<anonymous> (/home/software/Harsh Patel/test/demo_auth/server.js:4:14)
    at Module._compile (module.js:569:30)
    at Object.Module._extensions..js (module.js:580:10)
    at Module.load (module.js:503:32)
    at tryModuleLoad (module.js:466:12)
    at Function.Module._load (module.js:458:3)

我尝试用这些方法重新安装模块

1. npm install googleapis --save
2. npm install googleapis
3. npm install

但这些方法并不奏效。

我在 node_modules 目录