How To Use Xero API For Invoicing In Ruby on Rails

Xero is a popular accounting software with API endpoints available for developers. Here I will show you how to create invoices using Xero API.

What you will use

• www.xero.com, especially its APIs
• One of two gems to communicate with Xero API:
  • Xeroizer
  • Xero API wrapper (Xero Gateway)
• Xero for Developers - documentation for developers which allows them to be more familiar with this solution.
• Description of Xero API
  • Private
    • Private applications use 2-legged OAuth and bypass the user authorization workflow in the standard OAuth process. Private applications are linked to a single Xero organisation which is chosen when you register your application. Access tokens for private applications don’t expire unless the application is deleted or disconnected from within the Xero organisation.
  • Public
    • Public applications use the standard 3-legged OAuth process where user can authorise your application to have access to their Xero organisation. Public applications can either be web-based or installed on desktop/mobile. Access tokens expire after 30 minutes.
  • Partner
    • Partner applications are public applications that have been upgraded to support long term access tokens.

Xeroizer gem

Pros

• Allows to connect with Private, Public and Partner APIs
• Allows to use full functionality of API

Cons

• Requires SSL certificate (generated by OpenSSL)

Xero Gateway gem

Pros

•  Allows to connect with Private, Public and Partner APIs

Cons

• Not all methods are implemented

Take a look at Xero Getting Started Guide where you can find useful information and a simple guide which allows you to go through an implementation process easily. We are going to use a Xero demo company example, because it is a free solution and it's possible to reset it. You can also use trial version of Xero.com.  Here youhere: https://developer.xero.com/documentation/getting-started/development-accounts/ is a link which allows a developer to configure a Xero demo company app.

This blogpost might be useful for working with 2 and 3-legged OAuth: What is 2-legged OAuth

In this tutorial, we are going to use a private version of API. It requires generating certificates and is a little bit simpler than other kinds of an access to API.

Step 1

Create Xero demo app

Step 2

Create a private application (guide)
Please see a section titled Using OpenSSL. Key generation requires only these steps in your console

openssl genrsa -out privatekey.pem 1024
openssl req -new -x509 -key privatekey.pem -out publickey.cer -days 1825
openssl pkcs12 -export -out public_privatekey.pfx -inkey privatekey.pem -in publickey.cer

Step 3

You will end up with three files:

• privatekey.pem
• public_privatekey.pfx
• publickey.cer

Move them to app/certs in your application folder

Step 4

Install gem you prefer (I will show you examples for both of them below)

gem 'xeroizer'

or

gem 'xero_gateway'

and run bundle install

Step 5

Retrieve Xero API credentials (guide) and place them in your secrets.yml

development:
   secret_key_base:
   xero_consumer_key:
   xero_consumer_secret:
   cert_path: 'app/certs/privatekey.pem'

Step 6: Example request with Xeroizer

Here is a piece of code with allows a developer to connect with API and return all list with which is rendered inside a view

[code]

[code]

Step 7: Example request with Xero Gateway

Here is a piece of code with allows a developer to connect with API and return all list with which is rendered inside a view

[code]

[code]

Summary

Exceptions and unexpected situations

If you encounter any problems with API, you might be able to find an error at https://app.xero.com/Application/History where you can see latest queries to API.