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//Google Spreadsheet to JSON
function doGet(request) {
  var output = ContentService.createTextOutput();
  var data = {};
  var id = request.parameters.id;
  var sheet = request.parameters.sheet;
  var ss = SpreadsheetApp.openById(id);
  if (sheet) {
    data[sheet] = readData_(ss, sheet);
  } else {
    // Grab all sheets except those with a name
    // that starts with an underscore
    ss.getSheets().forEach(function(oSheet, iIndex) {
      var sName = oSheet.getName();
      if (! sName.match(/^_/)) {
        data[sName] = readData_(ss, sName);
      }
    })
  }
  var callback = request.parameters.callback;
  if (callback == undefined) {
    output.setContent(JSON.stringify(data));
    output.setMimeType(ContentService.MimeType.JSON);
  }
  else {
    output.setContent(callback + "(" + JSON.stringify(data) + ")");
    output.setMimeType(ContentService.MimeType.JAVASCRIPT);
  }
  return output;
}


function readData_(ss, sheetname, properties) {

  if (typeof properties == "undefined") {
    properties = getHeaderRow_(ss, sheetname);
    properties = properties.map(function(p) { return p.replace(/\s+/g, '_'); });
  }
  
  var rows = getDataRows_(ss, sheetname);
  var data = [];
  for (var r = 0, l = rows.length; r < l; r++) {
    var row = rows[r];
    var record = {};
    for (var p in properties) {
      record[properties[p]] = convert_(row[p]);
    }
    data.push(record);
  }
  return data;
}


function convert_(value) {
  if (value === "true") return true;
  if (value === "false") return false;
  return value;
}


function getDataRows_(ss, sheetname) {

  var sh = ss.getSheetByName(sheetname);
  return sh.getRange(2, 1, sh.getLastRow() - 1, sh.getLastColumn()).getValues();

}


function getHeaderRow_(ss, sheetname) {

  var sh = ss.getSheetByName(sheetname);
  return sh.getRange(1, 1, 1, sh.getLastColumn()).getValues()[0];

}