API Caller

api.coffee

class API
    constructor: (url) ->
        @url ?= apiURL
        @status =
            OK: 200,
            DONE: 4

        @cache = {}
        @cacheExpiration = 0 #seconds

    call: (query, callback) =>

        query ?= ''
        callback ?= () =>
            console.log 'Error: No callback'


        if not @cache[encodeURIComponent query]? or @.isExpired query
            xhr = new XMLHttpRequest()
            xhr.open 'GET', (@url + query), true
            xhr.onreadystatechange = @.processResponse xhr, query, callback, arguments[2]
            xhr.send()
        else
            callback @cache[encodeURIComponent query].data, arguments[2]

    isExpired: (query) ->
        now = new Date().getTime()
        ((now - @cache[encodeURIComponent query].time) / 1000) > @cacheExpiration

    processResponse: (xhr, query, callback, param = null) =>
        () =>
            if typeof callback is 'function'
                if xhr.readyState is @status.DONE and xhr.status = @status.OK
                    @cache[encodeURIComponent query] =
                        data: JSON.parse xhr.responseText
                        time: new Date().getTime()
                    callback (JSON.parse xhr.responseText), param