创建自定义组件并使用NoFlo运行

Question

我正在创建一个与MongoDB接口的自定义组件。我编写了一个只连接到MongoDB的CoffeeScript文件，并将其存储在noflo/components文件夹中。

MongoBase.coffee

noflo = require "noflo"
mongodb = require "mongodb"
url = require "url"

class exports.MongoBase extends noflo.Component
  constructor: ->
    super
    @inPorts =
      url: new noflo.Port()

    @inPorts.url.on "data", (data) =>
      try
        @parseConnectionString(data)
        @MongoClient = mongodb.MongoClient;
        @MongoClient.connect @serverUrl, (err, db) ->
          if err
            console.log("Error in connecting to MongoDB")
          else
            console.log("Connected to MongoDB")
      catch error
        console.log(error)
  parseConnectionString: (connectionString) =>
    databaseUrl = try
      url.parse(connectionString)
    catch error
      console.log(error) 
    [..., @serverUrl, @databaseName] = databaseUrl.split('/')
    @serverUrl = "mongo://" + @serverUrl

我将以下条目添加到component.json

"MongoBase": "components/MongoBase.coffee"

除此之外，我创建了一个mongo.fbp文件来检查组件的流程。FBP文件具有以下代码：

'mongodb://localhost:27017/test' -> url DocReader(MongoBase)

在运行noflo mongo.fbp时，我得到以下错误：

/home/saurabh/workspace/noflo/node_modules/fbp/lib/fbp.js:1628
        edges.forEach(function (o, i) {
              ^
TypeError: Object #<Object> has no method 'forEach'
  at Object.parser.registerEdges (/home/saurabh/workspace/noflo/node_modules/fbp/lib/fbp.js:1628:15)
  at peg$c25 (/home/saurabh/workspace/noflo/node_modules/fbp/lib/fbp.js:60:50)
  at peg$parseline (/home/saurabh/workspace/noflo/node_modules/fbp/lib/fbp.js:749:30)
  at peg$parsestart (/home/saurabh/workspace/noflo/node_modules/fbp/lib/fbp.js:282:12)
  at Object.parse (/home/saurabh/workspace/noflo/node_modules/fbp/lib/fbp.js:1650:18)
  at Object.exports.loadFBP (/home/saurabh/workspace/noflo/lib/Graph.js:1065:33)
  at /home/saurabh/workspace/noflo/lib/Graph.js:1116:24
  at fs.js:268:14
  at Object.oncomplete (fs.js:107:15)

我的代码或者我用来运行代码的步骤有问题吗？

Answer 1

您可能已经弄明白了这一点，因为您已经问了几个月了，但是我相信您需要在导出之前将getComponent()方法添加到您的类中。

noflo = require "noflo"
mongodb = require "mongodb"
url = require "url"

class MongoBase extends noflo.Component
  constructor: ->
    super
    @inPorts =
      url: new noflo.Port()

    @inPorts.url.on "data", (data) =>
      try
        @parseConnectionString(data)
        @MongoClient = mongodb.MongoClient;
        @MongoClient.connect @serverUrl, (err, db) ->
          if err
            console.log("Error in connecting to MongoDB")
          else
            console.log("Connected to MongoDB")
      catch error
        console.log(error)
  parseConnectionString: (connectionString) =>
    databaseUrl = try
      url.parse(connectionString)
    catch error
      console.log(error) 
    [..., @serverUrl, @databaseName] = databaseUrl.split('/')
    @serverUrl = "mongo://" + @serverUrl

MongoBase.getComponent = -> new MongoBase
exports.MongoBase = MongoBase

此外，在要使组件加载器工作的图中，您需要指定组件所在的包。如果您的package.json/component.json有一个类似"name": "mongo-base"的name条目，那么您必须在FBP图中指定它，如下所示：

'mongodb://localhost:27017/test' -> url DocReader(mongo-base/MongoBase)

注意:加载器会破坏包名称中的所有'noflo-'实例，因此需要考虑到这一点。例如，名字'noflo-mongo'会变成'mongo'__，所以当调用包的组件时，你应该在fbp DocReader(mongo/MongoBase)中编写，而不是在DocReader(noflo-mongo/MongoBase)__中。