A Google apps script to pull json from a spreadsheet

jsonPuller

function doGet(){
  var ss = SpreadsheetApp.openById("//key ommitted");
  return exportJSON(ss);
}


// Exports current sheet as JSON and displays in message box.
function exportJSON(ss) {
  var sheet = ss.getSheetByName("sessions");
  var rowsData = getRowsData(sheet);
  var result = Utilities.jsonStringify(rowsData);
  return result;
}

// getRowsData iterates row by row in the input range and returns an array of objects.
// Each object contains all the data for a given row, indexed by its normalized column name.
// Arguments:
//   - sheet: the sheet object that contains the data to be processed
//   - range: the exact range of cells where the data is stored
//   - columnHeadersRowIndex: specifies the row number where the column names are stored.
//       This argument is optional and it defaults to the row immediately above range; 
// Returns an Array of objects.
function getRowsData(sheet) {
  var headersRange = sheet.getRange(1, 1, sheet.getFrozenRows(), sheet.getMaxColumns());
  var headers = headersRange.getValues()[0];
  var dataRange = sheet.getRange(sheet.getFrozenRows()+1, 1, sheet.getMaxRows(), sheet.getMaxColumns());
  return getObjects(dataRange.getValues(), normalizeHeaders(headers));
}

// getColumnsData iterates column by column in the input range and returns an array of objects.
// Each object contains all the data for a given column, indexed by its normalized row name.
// Arguments:
//   - sheet: the sheet object that contains the data to be processed
//   - range: the exact range of cells where the data is stored
//   - rowHeadersColumnIndex: specifies the column number where the row names are stored.
//       This argument is optional and it defaults to the column immediately left of the range; 
// Returns an Array of objects.
function getColumnsData(sheet, range, rowHeadersColumnIndex) {
  rowHeadersColumnIndex = rowHeadersColumnIndex || range.getColumnIndex() - 1;
  var headersTmp = sheet.getRange(range.getRow(), rowHeadersColumnIndex, range.getNumRows(), 1).getValues();
  var headers = normalizeHeaders(arrayTranspose(headersTmp)[0]);
  return getObjects(arrayTranspose(range.getValues()), headers);
}


// For every row of data in data, generates an object that contains the data. Names of
// object fields are defined in keys.
// Arguments:
//   - data: JavaScript 2d array
//   - keys: Array of Strings that define the property names for the objects to create
function getObjects(data, keys) {
  var objects = [];
  for (var i = 0; i < data.length; ++i) {
    var object = {};
    var hasData = false;
    for (var j = 0; j < data[i].length; ++j) {
      var cellData = data[i][j];
      if (isCellEmpty(cellData)) {
        continue;
      }
      object[keys[j]] = cellData;
      hasData = true;
    }
    if (hasData) {
      objects.push(object);
    }
  }
  return objects;
}

// Returns an Array of normalized Strings.
// Arguments:
//   - headers: Array of Strings to normalize
function normalizeHeaders(headers) {
  var keys = [];
  for (var i = 0; i < headers.length; ++i) {
    var key = normalizeHeader(headers[i]);
    if (key.length > 0) {
      keys.push(key);
    }
  }
  return keys;
}

// Normalizes a string, by removing all alphanumeric characters and using mixed case
// to separate words. The output will always start with a lower case letter.
// This function is designed to produce JavaScript object property names.
// Arguments:
//   - header: string to normalize
// Examples:
//   "First Name" -> "firstName"
//   "Market Cap (millions) -> "marketCapMillions
//   "1 number at the beginning is ignored" -> "numberAtTheBeginningIsIgnored"
function normalizeHeader(header) {
  var key = "";
  var upperCase = false;
  for (var i = 0; i < header.length; ++i) {
    var letter = header[i];
    if (letter == " " && key.length > 0) {
      upperCase = true;
      continue;
    }
    if (!isAlnum(letter)) {
      continue;
    }
    if (key.length == 0 && isDigit(letter)) {
      continue; // first character must be a letter
    }
    if (upperCase) {
      upperCase = false;
      key += letter.toUpperCase();
    } else {
      key += letter.toLowerCase();
    }
  }
  return key;
}

// Returns true if the cell where cellData was read from is empty.
// Arguments:
//   - cellData: string
function isCellEmpty(cellData) {
  return typeof(cellData) == "string" && cellData == "";
}

// Returns true if the character char is alphabetical, false otherwise.
function isAlnum(char) {
  return char >= 'A' && char <= 'Z' ||
    char >= 'a' && char <= 'z' ||
    isDigit(char);
}

// Returns true if the character char is a digit, false otherwise.
function isDigit(char) {
  return char >= '0' && char <= '9';
}

// Given a JavaScript 2d Array, this function returns the transposed table.
// Arguments:
//   - data: JavaScript 2d Array
// Returns a JavaScript 2d Array
// Example: arrayTranspose([[1,2,3],[4,5,6]]) returns [[1,4],[2,5],[3,6]].
function arrayTranspose(data) {
  if (data.length == 0 || data[0].length == 0) {
    return null;
  }

  var ret = [];
  for (var i = 0; i < data[0].length; ++i) {
    ret.push([]);
  }

  for (var i = 0; i < data.length; ++i) {
    for (var j = 0; j < data[i].length; ++j) {
      ret[j][i] = data[i][j];
    }
  }

  return ret;
}