好吧，事件没什么人看。于是我看完 promise , 重写。 用 promise 就两件事 ：

1. 写 promise 风格的函数，返回 promise 的；
2. 用 promise 链 then , catch 组织。

本地测试通过了，网络测试未完成。点评禁了，返回的是 !220 : Forbiden ，这下不知怎办了。

错误能正常 catch，还不清楚会不会中断其它流，不知道 promise 这么组织对不对 ？

希望有人指教下…

代码如下：

http = require 'http'
cheerio = require 'cheerio'
fs = require 'fs'
Model = require './model'
mongoose = require 'mongoose'
STATUS_CODES = http.STATUS_CODES

loadWebPage = (url) ->
    promise = new Promise (resolve,reject) ->
        console.log 'loading : %s',url
        req = http.get url,(res) ->
            body = ''
            if res.statusCode isnt 200
                reject '!200 : %s',STATUS_CODES[res.statusCode]
            res.on 'data',(chunk) ->
                body += chunk
            res.on 'end', ->
                console.log 'body:' + body
                resolve body
        req.on 'error',(err) ->
            reject 'req error : %s',err

parsePage = (html) ->
    promise = new Promise (resolve,reject) ->
        console.log 'parse...'
        $ = cheerio.load html
        docs = []

        $('#shop-all-list ul li')
            .each (i,elem) ->
                model = new Object 
                    shopName : ''
                    link : ''
                    pic : ''
                    addr : ''
                    cate : 
                        life : new Array
                        buss : new Array
                    comment : new Array
                    
                #console.log 'i:%s',i
                #console.log i + ':' + $('.txt .tag-addr span',@).text()
                model.shopName = $('.txt .tit a',@).attr('title')
                model.link = $('.txt .tit a',@).attr('href')
                model.pic = $('.pic a img',@).attr('data-src')
                
                $('.txt .tag-addr',@)
                    .each (i,elem) ->
                        model.addr = $('.addr',@).text()
                        model.cate.life.push $('a span',@).eq(0).text(),$('a',@).eq(0).attr('href')
                        model.cate.buss.push $('a span',@).eq(1).text(),$('a',@).eq(1).attr('href')

                model.comment.push $('.txt .comment span',@).attr('title')

                $('.txt .comment a',@)
                    .each (i,elem) ->
                        model.comment.push $(@).children().text()
                docs.push model

        resolve docs
db = (docs) ->
    promise = new Promise (resolve,reject) ->
        console.log 'db runing...'
        Model.create docs,(err) ->
            if err then reject err else resolve()

readFile = (path) ->
    promise = new Promise (resolve,reject) ->
        console.log 'readding...'
        fs.readFile path,'utf8',(err,data) ->
            if err then reject err else resolve data

writeFile = (path,data) ->
    promise = new Promise (resolve,reject) ->
        console.log 'writing...'
        fs.writeFile path,JSON.stringify(data),(err) ->
            if err then reject err else resolve 'done!'

closeDB = ->
    console.log '\nall run.\nclose db.'
    mongoose.disconnect()

handleErr = (err) ->
    console.log 'has some error : %s',err

generateUrls = (url,prefix,limit) ->
    if typeof prefix is 'number'
        limit = prefix
        prefix = ''
    urls = []
    urls.push url
    urls.push url + prefix + i for i in [2..limit]

    urls

wizard = (Urls) ->
    if !Urls.length then return console.log 'all urls have run.'
    url = Urls.shift()
    promise = new Promise (resolve,reject) ->
        p = loadWebPage url
        #这个做两件事，一个重新开始，一个后面处理
        p.then ->
            wizard(Urls)
        p.then(parsePage).then(db).then(resolve).catch(reject)

#单个例子
opts = {
    host : 'www.dianping.com'
    path : '/search/category/100/10/g132'
    headers : {
        'User-Agent' : 'Mozilla/5.0 (Windows NT 6.1; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/41.0.2272.101 Safari/537.36'
    }
}
#url = 'http://www.dianping.com'

loadWebPage(opts)
    .then(parsePage)
    .then(db)
    .catch(handleErr)
    .then(closeDB)

#并发
#Urls = generateUrls url,'p',50
###
numberOfParallelRequests = 5
promises = wizard Urls for i in [2..numberOfParallelRequests]

Promise.all(promises)
    .then closeDB
    .catch (err)->
        wizard(Urls)
        handleErr(err)
###

#
#本地例子
#
###
filepath = './test/gz_movie_p1.html'
destpath = './test/test_promise.json'

readFile(filepath)
    .then (data) ->
        parsePage(data)
    .then (data) ->
        writeFile destpath,data
    .catch handleErr
    .then closeDB
###