tabletop.js

(function(global) {

  if (!Array.prototype.indexOf) {
    Array.prototype.indexOf = function (obj, fromIndex) {
      if (fromIndex == null) {
          fromIndex = 0;
      } else if (fromIndex < 0) {
          fromIndex = Math.max(0, this.length + fromIndex);
      }
      for (var i = fromIndex, j = this.length; i < j; i++) {
          if (this[i] === obj)
              return i;
      }
      return -1;
    };
  }
  
  /*
    Initialize with Tabletop.init( { key: '0AjAPaAU9MeLFdHUxTlJiVVRYNGRJQnRmSnQwTlpoUXc' } )
      OR!
    Initialize with Tabletop.init( { key: 'https://docs.google.com/spreadsheet/pub?hl=en_US&hl=en_US&key=0AjAPaAU9MeLFdHUxTlJiVVRYNGRJQnRmSnQwTlpoUXc&output=html&widget=true' } )
      OR!
    Initialize with Tabletop.init('0AjAPaAU9MeLFdHUxTlJiVVRYNGRJQnRmSnQwTlpoUXc')
  */

  "use strict";

  var Tabletop = global.Tabletop = function(options) {
    // Make sure Tabletop is being used as a constructor no matter what.
    if(!this || this === global) {
      return new Tabletop(options);
    }

    if(typeof(options) == 'string') {
      options = { key : options };
    }

    this.callback = options.callback;
    this.wanted = options.wanted || [];
    this.key = options.key;
    this.simpleSheet = !!options.simpleSheet;
    this.parseNumbers = !!options.parseNumbers;
    this.wait = !!options.wait;
    this.postProcess = options.postProcess;
    this.debug = !!options.debug;

    /* Be friendly about what you accept */
    if(/key=/.test(this.key)) {
      this.log("You passed a key as a URL! Attempting to parse.");
      this.key = this.key.match("key=(.*?)&")[1];
    }

    if(!this.key) {
      alert("You need to pass Tabletop a key!");
      return;
    }

    this.log("Initializing with key %s", this.key);

    this.models = {};
    this.model_names = [];

    this.base_json_url = "https://spreadsheets.google.com/feeds/worksheets/" + this.key + "/public/basic?alt=json-in-script";
    
    if(!this.wait) {
      this.fetch();
    }
  };

  // A global storage for callbacks.
  Tabletop.callbacks = {};

  // Backwards compatibility.
  Tabletop.init = function(options) {
    return new Tabletop(options);
  };

  Tabletop.sheets = function() {
    alert("Times have changed! You'll want to use var tabletop = Tabletop.init(...); tabletop.sheets(...); instead of Tabletop.sheets(...)");
  };

  Tabletop.prototype = {

    fetch: function(callback) {
      if(typeof(callback) !== "undefined") {
        this.callback = callback;
      }
      this.injectScript(this.base_json_url, this.loadSheets);
    },
    
    /*
      Insert the URL into the page as a script tag. Once it's loaded the spreadsheet data
      it triggers the callback. This helps you avoid cross-domain errors
      http://code.google.com/apis/gdata/samples/spreadsheet_sample.html

      Let's be plain-Jane and not use jQuery or anything.
    */
    injectScript: function(url, callback) {
      var script = document.createElement('script'),
          self = this,
          callbackName = 'tt' + (+new Date()) + (Math.floor(Math.random()*100000));
      // Create a temp callback which will get removed once it has executed,
      // this allows multiple instances of Tabletop to coexist.
      Tabletop.callbacks[ callbackName ] = function () {
        var args = Array.prototype.slice.call( arguments, 0 );
        callback.apply(self, args);
        script.parentNode.removeChild(script);
        delete Tabletop.callbacks[callbackName];
      };
      url = url + "&callback=" + 'Tabletop.callbacks.' + callbackName;
      script.src = url;
      document.getElementsByTagName('script')[0].parentNode.appendChild(script);
    },

    /* 
      Is this a sheet you want to pull?
      If { wanted: ["Sheet1"] } has been specified, only Sheet1 is imported
      Pulls all sheets if none are specified
    */
    isWanted: function(sheetName) {
      if(this.wanted.length === 0) {
        return true;
      } else {
        return this.wanted.indexOf(sheetName) != -1;
      }
    },
    
    /*
      What gets send to the callback
      if simpleSheet == true, then don't return an array of Tabletop.this.models,
      only return the first one's elements
    */
    data: function() {
      // If the instance is being queried before the data's been fetched
      // then return undefined.
      if(this.model_names.length === 0) {
        return undefined;
      }
      if(this.simpleSheet) {
        if(this.model_names.length > 1 && this.debug)
          console.debug("WARNING You have more than one sheet but are using simple sheet mode! Don't blame me when something goes wrong.");
        return this.models[ this.model_names[0] ].all();
      } else {
        return this.models;
      }
    },

    /*
      Add another sheet to the wanted list
    */
    addWanted: function(sheet) {
      if(this.wanted.indexOf(sheet) == -1) {
        this.wanted.push(sheet)
      }
    },
    
    /*
      Load all worksheets of the spreadsheet, turning each into a Tabletop Model.
      Need to use injectScript because the worksheet view that you're working from
      doesn't actually include the data. The list-based feed (/feeds/list/key..) does, though.
      Calls back to loadSheet in order to get the real work done.

      Used as a callback for the worksheet-based JSON
    */
    loadSheets: function(data) {
      var i, ilen;
      var toInject = [];

      for(i = 0, ilen = data.feed.entry.length; i < ilen ; i++) {
        // Only pull in desired sheets to reduce loading
        if( this.isWanted(data.feed.entry[i].content.$t) ) {
          var sheet_id = data.feed.entry[i].link[3].href.substr( data.feed.entry[i].link[3].href.length - 3, 3);
          var json_url = "https://spreadsheets.google.com/feeds/list/" + this.key + "/" + sheet_id + "/public/values?alt=json-in-script";
          toInject.push(json_url);
        }
      }

      this.sheetsToLoad = toInject.length;
      for(i = 0, ilen = toInject.length; i < ilen; i++) {
        this.injectScript(toInject[i], this.loadSheet);
      }
    },

    /*
      Access layer for the this.models
      .sheets() gets you all of the sheets
      .sheets('Sheet1') gets you the sheet named Sheet1
    */
    sheets: function(sheetName) {
      if(typeof sheetName === "undefined")
        return this.models;
      else
        if(typeof(this.models[ sheetName ]) === "undefined") {
          // alert( "Can't find " + sheetName );
          return;
        } else {
          return this.models[ sheetName ];
        }
    },

    /*
      Parse a single list-based worksheet, turning it into a Tabletop Model

      Used as a callback for the list-based JSON
    */
    loadSheet: function(data) {
      var model = new Tabletop.Model( { data: data, 
                                    parseNumbers: this.parseNumbers,
                                    postProcess: this.postProcess } );
      this.models[ model.name ] = model;
      if(this.model_names.indexOf(model.name) == -1) {
        this.model_names.push(model.name);
      }
      this.sheetsToLoad--;
      if(this.sheetsToLoad === 0)
        this.doCallback();
    },

    /*
      Execute the callback upon loading! Rely on this.data() because you might
        only request certain pieces of data (i.e. simpleSheet mode)
      Tests this.sheetsToLoad just in case a race condition happens to show up
    */
    doCallback: function() {
      if(this.sheetsToLoad === 0)
        this.callback(this.data(), this);
    },

    log: function(msg) {
      if(this.debug) {
        if(typeof console !== "undefined" && typeof console.log !== "undefined") {
            console.log(msg)
        }
      }
    }

  };

  /*
    Tabletop.Model stores the attribute names and parses the worksheet data
      to turn it into something worthwhile

    Options should be in the format { data: XXX }, with XXX being the list-based worksheet
  */
  Tabletop.Model = function(options) {
    var i, j, ilen, jlen;
    this.column_names = [];
    this.name = options.data.feed.title.$t;
    this.elements = [];
    this.raw = options.data; // A copy of the sheet's raw data, for accessing minutiae

    for(var key in options.data.feed.entry[0]){
      if(/^gsx/.test(key))
        this.column_names.push( key.replace("gsx$","") );
    }

    for(i = 0, ilen =  options.data.feed.entry.length ; i < ilen; i++) {
      var source = options.data.feed.entry[i];
      var element = {};
      for(var j = 0, jlen = this.column_names.length; j < jlen ; j++) {
        var cell = source[ "gsx$" + this.column_names[j] ];
        if(options.parseNumbers && cell.$t !== '' && !isNaN(cell.$t))
          element[ this.column_names[j] ] = +cell.$t;
        else
          element[ this.column_names[j] ] = cell.$t;
      }
      if(element.rowNumber === undefined)
        element.rowNumber = i + 1;
      if( options.postProcess )
        options.postProcess(element);
      this.elements.push(element);
    }

  };

  Tabletop.Model.prototype = {
    /*
      Returns all of the elements (rows) of the worksheet as objects
    */
    all: function() {
      return this.elements;
    },

    /*
      Return the elements as an array of arrays, instead of an array of objects
    */
    toArray: function() {
      var array = [],
          i, j, ilen, jlen;
      for(i = 0, ilen = this.elements.length; i < ilen; i++) {
        var row = [];
        for(j = 0, jlen = this.column_names.length; j < jlen ; j++) {
          row.push( this.elements[i][ this.column_names[j] ] );
        }
        array.push(row);
      }
      return array;
    }
  };

})(this);