The document provides a tutorial for creating a simple invoicing app using Google Apps Script with Google Sheets as a database. It outlines the process of retrieving customer and transaction data, organizing it, generating invoices, and sending them via email. Further homework includes enhancing the app with better error handling and email templating solutions.

1. do something useful with
Apps Script in 5 minutes
3.Simple invoicing app
Bruce McPherson
www.mcpher.com

2. Snippet objectives
● Use the lessons learned in ‘using a spreadsheet as a
database’
● Gets transactions and master data from database. I’m
using sheets as the database here.
● Calculates and generates personalized invoice emails
Libraries used
● database abstraction
● driver sheet

3. Add libraries to script
create a script
Open resources
Add references to libraries
Mrckbr9_w7PCphJtOzhzA_Cz3TLx7pV4j
MHfCjPQlweartW45xYs6hFai_d-phDA33

4. Take a copy of the test data
Product and Customer data
https://docs.google.com/spreadsheets/d/1EhgZ1-q9tP1u9BSEQPIQiSGozdfjsHn3zB1JfQGbftw/edit?usp=sharing
Transaction data
https://docs.google.com/spreadsheets/d/1gmOEvILq0wygW3iN9exe4P0iu0x2wgwlX25D_QHgq10/edit?usp=sharing

5. layout what you are going to do
function myFunction() {
// get customer handle
// get product handle
// get transactions handle
// get all the transaction data ready to be invoiced
// organize into customers/transactions
// now we have an array of customers and their associated transactions - join to masters
// produce and email invoice with multiple transactions per customer
}

6. create function for repeated patterns
/**
* open a sheet as a database
* @param {string} sheetName the sheetName
* @param {string} sheetId the spreadsheet id
* @return {DbAbstraction} the handle
*/
function getHandle ( sheetName, sheetId) {
// open spreadsheet as database
var handler = new cDbAbstraction.DbAbstraction (cDriverSheet, {
siloid:sheetName,
dbid:sheetId,
});
if (!handler.isHappy()) throw 'unable to open sheet';
return handler;
}
We’ll call this function for each
of the database tables we
need to open

7. Get handlers for each table
// get customer handle
var customerHandle = getHandle ('customers' , '1EhgZ1-q9tP1u9BSEQPIQiSGozdfjsHn3zB1JfQGbftw');
// get product handle
var productHandle = getHandle ('products' , '1EhgZ1-q9tP1u9BSEQPIQiSGozdfjsHn3zB1JfQGbftw');
// get transactions handle
var transactionHandle = getHandle ('transactions' , '1gmOEvILq0wygW3iN9exe4P0iu0x2wgwlX25D_QHgq10');

8. Get the transaction data and sort it
// get all the transaction data ready to be invoiced
var transactionResult = transactionHandle.query ({status:'delivered'},{sort:'customer id'});
if (transactionResult.handleCode < 0) throw transactionResult.handleError;

9. Reduce transactions
// organize into customers/transactions - data is already sorted
var customerTransactions = transactionResult.data.reduce ( function (p,c) {
var t = p.length ? p[p.length-1] : null;
if (!t || c['customer id'] !== t.cid) {
// its a new customer
p.push( t = {cid:c['customer id'], transactions:[]} );
}
t.transactions.push(c);
return p;
},[]);
Reduce to one object per
customer, so we can
consolidate transactions to a
single invoice

10. Join transactions to masters
// now we have an array of customers and their associated transactions - join to masters
customerTransactions.forEach ( function (d) {
var result = customerHandle.query ({"customer id":d.cid});
// just fail if customer not found
if ( result.handleCode < 0 || result.data.length !== 1 ) throw JSON.stringify(result);
d.customer = result.data.slice()[0];
Look up the master data from
customers and product table
and join to transactions
// get the product data
d.transactions.forEach (function (p){
var result = productHandle.query ({"product id":p['product id']});
if ( result.handleCode < 0 || result.data.length !== 1 ) throw JSON.stringify(result);
p.product = result.data.slice()[0];
});
});

11. Function to create email content
function getEmailContent (d) {
return '<div>'
+ d.customer.company + '<br>'
+ '<table><tbody><th>Product name</th><th>Quantity</th><th>Total</th>'
+ d.transactions.map(function(e) {
return '<tr><td>'+e.product['product name']
+'</td><td>'+e.quantity
+'</td><td>'+e.quantity*e.product['unit price']
+'</td></tr>';
}).join(‘’)
+ '<tr><td>Total</td><td></td><td>'
+ d.transactions.reduce(function(p,c) {
return p+c.quantity*c.product['unit price'];
},0)
+ '</td></tr>'
+ '</tbody></table>'
+ '</div>';
}
Very basic email invoice. You’d
probably want to spruce up
and use a proper template

12. Send email invoices
customerTransactions.forEach (function(d) {
MailApp.sendEmail({
to: d.customer.email,
subject: "Invoice from desktop liberation",
htmlBody: getEmailContent (d)
});
});
Very basic email invoice. You’d
probably want to spruce up
and use a proper template

13. Further homework
● Using what you learned in graduating to a
database, why not migrate some of the test
data to a database and redo.
● Incorporate a real email templating solution
like Romain Vialard’s YAMM
● Improve error handling
● Update database status when email is sent

14. Follow up materials
Take a copy of this script
Take a copy of these slides
Join me on G+, or the G+ community
More on desktop liberation
More on database abstraction