Question

我正在尝试访问Express＆＃39; app＆＃39;变量在我的应用程序的一个子模块中。一种方法是在调用子模块时将其作为参数传递，但我想避免使用它。 This solution提到它是可能的，但是每次我尝试它都会得到异常，说对象不是函数（下面的回溯）

server.coffee

express = require 'express'

# Application Config
config = require './lib/config/config'
app = express()

# Start server
server = app.listen config.port, ->
  logger.info "Express server listening on port #{config.port} in #{app.get("env")} mode"

# load procesor
fooBarStreamProcessor = require('./lib/modules/fooBarStreamProcessor')
fooBarUpstream = new fooBarStreamProcessor(config.fooBar_host, config.fooBar_port)

# Expose app
exports = module.exports = app

fooBarStreamProcessor.coffee

  events             = require('events')
  eventEmitter       = new events.EventEmitter()
  app = require("../../server")

  console.log(app.get('something'))

  module.exports = ->
    return "I am some function"

回溯

  TypeError: object is not a function
    at Object.<anonymous> (~/devel/exampleproj/server.coffee:30:18)
    at Object.<anonymous> (~/devel/exampleproj/server.coffee:1:1)
    at Module._compile (module.js:456:26)
    at Object.loadFile (~/devel/exampleproj/node_modules/coffee-script/lib/coffee-script/register.js:16:19)
    at Module.load (~/devel/exampleproj/node_modules/coffee-script/lib/coffee-script/register.js:45:36)
    at Function.Module._load (module.js:312:12)
    at Module.require (module.js:364:17)
    at require (module.js:380:17)
    at Object.<anonymous> (~/devel/exampleproj/lib/modules/fooBarStreamProcessor.coffee:9:7)
    at Object.<anonymous> (~/devel/exampleproj/lib/modules/fooBarStreamProcessor.coffee:1:1)
    at Module._compile (module.js:456:26)
    at Object.loadFile (~/devel/exampleproj/node_modules/coffee-script/lib/coffee-script/register.js:16:19)
    at Module.load (~/devel/exampleproj/node_modules/coffee-script/lib/coffee-script/register.js:45:36)
    at Function.Module._load (module.js:312:12)
    at Module.require (module.js:364:17)
    at require (module.js:380:17)
    at Object.<anonymous> (~/devel/exampleproj/server.coffee:3:25)
    at Object.<anonymous> (~/devel/exampleproj/server.coffee:1:1)
    at Module._compile (module.js:456:26)

检查后，fooBarStreamProcessor似乎设置为{}，而不是fooBarStreamProcessor.coffee所需的实际功能。在进行问题排查时，我尝试在require("./server")的第一行中添加server.coffee之类的内容，但它排除了错误，但代码执行了两次。

任何想法我该如何解决这个问题？

Answer 1

问题是，在包含子模块之后，此行将被执行：

# Expose app exports = module.exports = app

尝试将其移至应用定义：

app = module.exports = express()

并确保在需要子模块之前在应用上设置任何所需内容。

Answer 2

是的，你有一个循环依赖。通常这意味着在需要的时候而不是在文件的开头加载一个，但是在这样的情况下，您的示例代码中并不清楚。在fooBarStreamProcessor.coffee中，您可能需要server在您要导出的功能中。

events             = require('events')
eventEmitter       = new events.EventEmitter()

module.exports = ->
  app = require("../../server")
  console.log(app.get('something'))

  return "I am some function"

Answer 3

找到解决方案 - 导致问题的是Coffeescripts全局包装器。使用'-b'（裸）选项编译coffeescript会阻止这种情况发生。有趣的是，运行coffeescript（没有-c标志）会导致出现相同的错误。

NodeJS，循环依赖：主模块不在缓存中？

3 个答案: