| 1 | This is a minimalist CouchDB (HTTP) API
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| 2 | It provides exactly what this module needs, but no more.
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| 3 |
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| 4 | LRU = require 'lru-cache'
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| 5 | {EventEmitter2} = require 'eventemitter2'
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| 6 |
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| 7 | http = require 'http'
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| 8 | https = require 'https'
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| 9 |
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| 10 | lru_dispose = new EventEmitter2 newListener: false, verboseMemoryLeak: true
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| 11 |
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| 12 | options =
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| 13 | max: 200
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| 14 | dispose: (key) -> ev.emit key
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| 15 | maxAge: 20*60*1000
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| 16 |
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| 17 | lru_cache = LRU options
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| 18 |
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| 19 | static_cache = new Map()
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| 20 |
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| 21 | class CouchDB
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| 22 |
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| 23 | constructor: (uri,use_lru) ->
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| 24 | if uri.match /\/$/
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| 25 | @uri = uri
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| 26 | else
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| 27 | @uri = "#{uri}/"
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| 28 |
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| 29 | if use_lru
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| 30 | @cache = lru_cache
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| 31 | @limit = most.fromEvent @uri, lru_dispose
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| 32 | else
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| 33 | @cache = static_cache
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| 34 | @limit = most.never()
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| 35 |
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| 36 | switch
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| 37 | when uri.match /^http:/
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| 38 | @agent = agent.agent http.globalAgent
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| 39 | when uri.match /^https:/
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| 40 | @agent = agent.agent https.globalAgent
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| 41 | else
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| 42 | @agent = agent
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| 43 |
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| 44 | return
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| 45 |
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| 46 | put: (doc) ->
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| 47 | {_id} = doc
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| 48 | uri = new URL ec(_id), @uri
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| 49 | @agent
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| 50 | .put uri.toString()
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| 51 | .type 'json'
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| 52 | .accept 'json'
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| 53 | .send doc
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| 54 | .then ({body}) -> body
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| 55 |
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| 56 | get: (_id,{rev} = {}) ->
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| 57 | uri = new URL ec(_id), @uri
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| 58 | uri.searchParams.set 'rev', rev if rev?
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| 59 | @agent
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| 60 | .get uri.toString()
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| 61 | .accept 'json'
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| 62 | .then ({body}) -> body
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| 63 |
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| 64 | delete: ({_id,_rev}) ->
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| 65 | uri = new URL ec(_id), @uri
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| 66 | uri.searchParams.set 'rev', _rev if _rev?
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| 67 | @agent
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| 68 | .delete uri.toString()
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| 69 | .accept 'json'
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| 70 | .then ({body}) -> body
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| 71 |
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| 72 | changes: (options = {}) ->
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| 73 | {live,include_docs,since} = options
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| 74 | live ?= true
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| 75 | throw new Error 'Only live streaming is supported' unless live is true
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| 76 |
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| 77 | if @cache.has @uri
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| 78 | return @cache.get @uri
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| 79 |
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| 80 | since ?= 'now'
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| 81 | uri = new URL '_changes', @uri
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| 82 | uri.searchParams.set 'feed', 'eventsource'
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| 83 | uri.searchParams.set 'heartbeat', true
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| 84 | uri.searchParams.set 'include_docs', include_docs ? false
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| 85 |
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| 86 | The stream might end because the server disconnects or other errors.
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| 87 | In all cases we let it finish cleanly.
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| 88 |
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| 89 | s = ->
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| 90 | uri.searchParams.set 'since', since
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| 91 | fromEventSource new EventSource uri.toString()
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| 92 | .continueWith ->
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| 93 | console.error 'retry', uri.host, uri.pathname, since
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| 94 | most.never()
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| 95 | .recoverWith (error) ->
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| 96 | console.error 'retry', (error.stack ? error), uri.host, uri.pathname, since
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| 97 | most.never()
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| 98 |
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| 99 | stream = autoRestart(s)
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| 100 | .map ({data}) -> data
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| 101 | .map JSON.parse
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| 102 | .tap ({seq}) -> since = seq if seq?
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| 103 | .until @limit
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| 104 | .multicast()
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| 105 |
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| 106 | @cache.set @uri, stream
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| 107 | stream
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| 108 |
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| 109 | module.exports = CouchDB
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| 110 | ec = encodeURIComponent
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| 111 | most = require 'most'
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| 112 | EventSource = require 'eventsource'
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| 113 | {fromEventSource} = require 'most-w3msg'
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| 114 | {URL} = require 'url'
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| 115 | agent = require 'superagent'
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| 116 |
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| 117 | When the stream finishes, we restart it with a small delay.
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| 118 |
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| 119 | sleep = (timeout) -> new Promise (resolve) -> setTimeout resolve, timeout
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| 120 |
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| 121 | autoRestart = (s) ->
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| 122 |
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| 123 | most
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| 124 | .generate -> yield 200
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| 125 | .startWith 0
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| 126 | .map (delay) ->
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| 127 | await sleep delay
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| 128 | s()
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| 129 | .chain most.fromPromise
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| 130 | .switchLatest()
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