| 1 | _ = require 'lodash'
|
| 2 | s3 = require 's3'
|
| 3 | CHANNEL_S3_BUCKET = 'octoblu-channels'
|
| 4 | CHANNEL_S3_KEY = 'channels.json'
|
| 5 |
|
| 6 | class ChannelDownloader
|
| 7 | constructor: ->
|
| 8 | @cached = false
|
| 9 | @etag = null
|
| 10 | @data = null
|
| 11 | @_checkEtag = _.throttle @_checkEtagImmediately, 60*1000*5, leading: true, trailing: false
|
| 12 |
|
| 13 | setOptions: (options) =>
|
| 14 | @s3client ?= s3.createClient
|
| 15 | s3Options:
|
| 16 | accessKeyId: options.accessKeyId
|
| 17 | secretAccessKey: options.secretAccessKey
|
| 18 |
|
| 19 | update: (callback) =>
|
| 20 | @_checkEtag()
|
| 21 | return callback null, @data if @cached
|
| 22 |
|
| 23 | downloader = @s3client.downloadBuffer
|
| 24 | Bucket: CHANNEL_S3_BUCKET
|
| 25 | Key: CHANNEL_S3_KEY
|
| 26 |
|
| 27 | downloader.on 'httpHeaders', (statusCode, headers) ->
|
| 28 | @etag = headers.etag
|
| 29 |
|
| 30 | downloader.on 'error', callback
|
| 31 | downloader.on 'end', (buffer) =>
|
| 32 | try
|
| 33 | @data = JSON.parse buffer
|
| 34 | catch error
|
| 35 | return callback error
|
| 36 |
|
| 37 | @cached = true
|
| 38 | callback null, @data
|
| 39 |
|
| 40 | _checkEtagImmediately: =>
|
| 41 | list = @s3client.listObjects
|
| 42 | s3Params:
|
| 43 | Bucket: CHANNEL_S3_BUCKET
|
| 44 |
|
| 45 | list.on 'data', (data) =>
|
| 46 | entry = _.find data.Contents, {'Key': 'channels.json'}
|
| 47 | return unless entry?
|
| 48 | return if @etag == entry.ETag
|
| 49 | @etag = entry.ETag
|
| 50 | @cached = false
|
| 51 |
|
| 52 | module.exports = ChannelDownloader
|