Learn more
 

Ready to get started?

Learn more or sign up for a free trial:

CData Connect Server

In this article

Related articles

Connect to CouchDB Data in Google Apps Script


Use CData Connect Server to access CouchDB data in Google Apps Script.

Google Apps Script gives you the ability to create custom functionality within your Google documents, including Google Sheets, Google Docs, and more. With CData Connect Server, you get a SQL Server interface for any of the 200+ sources supported by CData, including CouchDB. The SQL Server protocol is natively supported through the JDBC service in Google Apps Script, so by utilizing Connect Server, you gain access to live CouchDB data within your Google documents.

This article shows how to create a virtual database for CouchDB in Connect Server and provides sample scripting for processing CouchDB data in a Google Spreadsheet.

Our script only reads data from a specified table, but you can easily extend the script to incorporate update functionality.

CData Connect Server provides a pure SQL Server interface for CouchDB, allowing you to easily build reports from live CouchDB data in Apps Script — without replicating the data to a natively supported database. As you build visualizations, Apps Script generates SQL queries to gather data. Using optimized data processing out of the box, CData Connect Server pushes all supported SQL operations (filters, JOINs, etc) directly to CouchDB, leveraging server-side processing to quickly return the requested CouchDB data.

Create a Virtual SQL Server Database for CouchDB Data

CData Connect Server uses a straightforward, point-and-click interface to connect to data sources and generate APIs.

  1. Login to Connect Server and click Connections.
  2. Select "CouchDB" from Available Data Sources.
  3. Enter the necessary authentication properties to connect to CouchDB.

    Set the following to connect:

    • Url: The Url of your instance. For example: http://localhost:5984
    • User The Apache CouchDB user account used to authenticate.
    • Password The Apache CouchDB password associated with the authenticating user.
  4. Click Save Changes
  5. Click Privileges -> Add and add the new user (or an existing user) with the appropriate permissions.

With the virtual database created, you are ready to connect to CouchDB data from Apps Script.

Connect to CouchDB Data with Apps Script

At this point, you should have configured a virtual database for CouchDB in Connect Server. All that is left now is to use Google Apps Script to access Connect Server and work with your CouchDB data in Google Sheets.

In this section, you will create a script (with a menu option to call the script) to populate a spreadsheet with CouchDB data. We have created a sample script and explained the different parts. You can view the raw script at the end of the article.

1. Create an Empty Script

To create a script for your Google Sheet, click Tools Script editor from the Google Sheets menu:

Open Script Editor

2. Declare Class Variables

Create a handful of class variables to be available for any functions created in the script. 

//replace the variables in this block with real values as needed
var address = 'CONNECT_SERVER_URL:port';
var user = 'CONNECT_USER';
var userPwd = 'CONNECT_PASSWORD';
var db = 'couchdbdb';
var serverSslCert = '-----BEGIN CERTIFICATE-----
...
-----END CERTIFICATE-----';
var clientSslCert = '-----BEGIN CERTIFICATE-----
...
-----END CERTIFICATE-----';
var clientSslKey  = '-----BEGIN CERTIFICATE-----
...
-----END CERTIFICATE-----';

var dbUrl = 'jdbc:sqlserver://' + address + '/' + db + '?useSSL=true';

3. Add a Menu Option

This function adds a menu option to your Google Sheet, allowing you to use the UI to call your function.

function onOpen() {
  var spreadsheet = SpreadsheetApp.getActive();
  var menuItems = [
    {name: 'Write data to a sheet', functionName: 'connectToApacheCouchDBData'}
  ];
  spreadsheet.addMenu('CouchDB Data', menuItems);
}
The newly added Menu option.

4. Write a Helper Function

This function is used to find the first empty row in a spreadsheet.

/*
 * Finds the first empty row in a spreadsheet by scanning an array of columns
 * @return The row number of the first empty row.
 */
function getFirstEmptyRowByColumnArray(spreadSheet, column) {
  var column = spreadSheet.getRange(column + ":" + column);
  var values = column.getValues(); // get all data in one call
  var ct = 0;
  while ( values[ct] && values[ct][0] != "" ) {
    ct++;
  }
  return (ct+1);
}

5. Write a Function to Write CouchDB Data to a Spreadsheet

The function below writes the CouchDB data, using the Google Apps Script JDBC functionality to connect to Connect Server, SELECT data, and populate a spreadsheet. When the script is run, two input boxes will appear:

The first one asks the user to input the name of a sheet to hold the data (if the spreadsheet does not exist, the function creates it).

Input box for sheet selection.

The second asks the user to input the name of a CouchDB table to read. If an invalid table is chosen, an error message appears and the function is exited.

Input box for table selection.

Note, while the function is designed for use as a menu option, you can extend it for use as a spreadsheet formula.

/*
 * Reads data from a specified CouchDB 'table' and writes it to the specified sheet.
 *    (If the specified sheet does not exist, it is created.)
 */
function connectToApacheCouchDBData() {
  var thisWorkbook = SpreadsheetApp.getActive();

  //select a sheet and create it if it does not exist
  var selectedSheet = Browser.inputBox('Which sheet would you like the data to post to?',Browser.Buttons.OK_CANCEL);
  if (selectedSheet == 'cancel')
    return;

  if (thisWorkbook.getSheetByName(selectedSheet) == null)
    thisWorkbook.insertSheet(selectedSheet);
  var resultSheet = thisWorkbook.getSheetByName(selectedSheet);
  var rowNum = 2;

  //select a CouchDB 'table'
  var table = Browser.inputBox('Which table would you like to pull data from?',Browser.Buttons.OK_CANCEL);
  if (table == 'cancel')
    return;

  var conn = Jdbc.getConnection(dbUrl, {
    user: user, 
    password: userPwd, 
    _serverSslCertificate: serverSslCert,
    _clientSslCertificate: clientSslCert,
    _clientSslKey:         clientSslKey
  );

  //confirm that var table is a valid table/view
  var dbMetaData = conn.getMetaData();
  var tableSet = dbMetaData.getTables(null, null, table, null);
  var validTable = false;
  while (tableSet.next()) {
    var tempTable = tableSet.getString(3);
    if (table.toUpperCase() == tempTable.toUpperCase()){
      table = tempTable;
      validTable = true;
      break;
    }
  } 
  tableSet.close();
  if (!validTable) {
    Browser.msgBox("Invalid table name: " + table, Browser.Buttons.OK);
    return;
  }

  var stmt = conn.createStatement();

  var results = stmt.executeQuery('SELECT * FROM ' + table);
  var rsmd = results.getMetaData();
  var numCols = rsmd.getColumnCount();

  //if the sheet is empty, populate the first row with the headers
  var firstEmptyRow = getFirstEmptyRowByColumnArray(resultSheet, "A");
  if (firstEmptyRow == 1) {
    //collect column names
    var headers = new Array(new Array(numCols));
    for (var col = 0; col < numCols; col++){
      headers[0][col] = rsmd.getColumnName(col+1);
    }
    resultSheet.getRange(1, 1, headers.length, headers[0].length).setValues(headers);
  } else {
    rowNum = firstEmptyRow;
  }

  //write rows of CouchDB data to the sheet
  var values = new Array(new Array(numCols));
  while (results.next()) {
    for (var col = 0; col < numCols; col++) {
      values[0][col] = results.getString(col + 1);
    }
    resultSheet.getRange(rowNum, 1, 1, numCols).setValues(values);
    rowNum++;
  }

  results.close();
  stmt.close();
}

When the function is completed, you have a spreadsheet populated with your CouchDB data, and you can now leverage all of the calculating, graphing, and charting functionality of Google Sheets anywhere you have access to the Internet.

Complete Google Apps Script

//replace the variables in this block with real values as needed
var address = 'CONNECT_SERVER_URL:port';
var user = 'CONNECT_USER';
var userPwd = 'CONNECT_PASSWORD';
var db = 'couchdbdb';
var serverSslCert = '-----BEGIN CERTIFICATE-----
...
-----END CERTIFICATE-----';
var clientSslCert = '-----BEGIN CERTIFICATE-----
...
-----END CERTIFICATE-----';
var clientSslKey  = '-----BEGIN CERTIFICATE-----
...
-----END CERTIFICATE-----';

var dbUrl = 'jdbc:sqlserver://' + address + '/' + db + '?useSSL=true';

function onOpen() {
  var spreadsheet = SpreadsheetApp.getActive();
  var menuItems = [
    {name: 'Write table data to a sheet', functionName: 'connectToApacheCouchDBData'}
  ];
  spreadsheet.addMenu('CouchDB Data', menuItems);
}

/*
 * Finds the first empty row in a spreadsheet by scanning an array of columns
 * @return The row number of the first empty row.
 */
function getFirstEmptyRowByColumnArray(spreadSheet, column) {
  var column = spreadSheet.getRange(column + ":" + column);
  var values = column.getValues(); // get all data in one call
  var ct = 0;
  while ( values[ct] && values[ct][0] != "" ) {
    ct++;
  }
  return (ct+1);
}

/*
 * Reads data from a specified 'table' and writes it to the specified sheet.
 *    (If the specified sheet does not exist, it is created.)
 */
function connectToApacheCouchDBData() {
  var thisWorkbook = SpreadsheetApp.getActive();

  //select a sheet and create it if it does not exist
  var selectedSheet = Browser.inputBox('Which sheet would you like the data to post to?',Browser.Buttons.OK_CANCEL);
  if (selectedSheet == 'cancel')
    return;

  if (thisWorkbook.getSheetByName(selectedSheet) == null)
    thisWorkbook.insertSheet(selectedSheet);
  var resultSheet = thisWorkbook.getSheetByName(selectedSheet);
  var rowNum = 2;

  //select a CouchDB 'table'
  var table = Browser.inputBox('Which table would you like to pull data from?',Browser.Buttons.OK_CANCEL);
  if (table == 'cancel')
    return;

  var conn = Jdbc.getConnection(dbUrl, {
    user: user, 
    password: userPwd, 
    _serverSslCertificate: serverSslCert,
    _clientSslCertificate: clientSslCert,
    _clientSslKey:         clientSslKey
  );

  //confirm that var table is a valid table/view
  var dbMetaData = conn.getMetaData();
  var tableSet = dbMetaData.getTables(null, null, table, null);
  var validTable = false;
  while (tableSet.next()) {
    var tempTable = tableSet.getString(3);
    if (table.toUpperCase() == tempTable.toUpperCase()){
      table = tempTable;
      validTable = true;
      break;
    }
  } 
  tableSet.close();
  if (!validTable) {
    Browser.msgBox("Invalid table name: " + table, Browser.Buttons.OK);
    return;
  }

  var stmt = conn.createStatement();

  var results = stmt.executeQuery('SELECT * FROM ' + table);
  var rsmd = results.getMetaData();
  var numCols = rsmd.getColumnCount();

  //if the sheet is empty, populate the first row with the headers
  var firstEmptyRow = getFirstEmptyRowByColumnArray(resultSheet, "A");
  if (firstEmptyRow == 1) {
    //collect column names
    var headers = new Array(new Array(numCols));
    for (var col = 0; col < numCols; col++){
      headers[0][col] = rsmd.getColumnName(col+1);
    }
    resultSheet.getRange(1, 1, headers.length, headers[0].length).setValues(headers);
  } else {
    rowNum = firstEmptyRow;
  }

  //write rows of CouchDB data to the sheet
  var values = new Array(new Array(numCols));
  while (results.next()) {
    for (var col = 0; col < numCols; col++) {
      values[0][col] = results.getString(col + 1);
    }
    resultSheet.getRange(rowNum, 1, 1, numCols).setValues(values);
    rowNum++;
  }

  results.close();
  stmt.close();
}