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Xeroizer API Library

Homepage: http://waynerobinson.github.com/xeroizer
Git: git://github.com/waynerobinson/xeroizer.git
Github: https://github.com/waynerobinson/xeroizer
Author: Wayne Robinson http://www.wayne-robinson.com
Contributors: See Contributors section below
Copyright: 2007-2013 License: MIT License

Introduction

This library is designed to help ruby/rails based applications communicate with the publicly available API for Xero.

If you are unfamiliar with the Xero API, you should first read the documentation located at http://developer.xero.com.

Installation

gem install xeroizer

Basic Usage

require 'rubygems'
require 'xeroizer'

# Create client (used to communicate with the API).
client = Xeroizer::PublicApplication.new(YOUR_OAUTH_CONSUMER_KEY, YOUR_OAUTH_CONSUMER_SECRET)

# Retrieve list of contacts (note: all communication must be made through the client).
contacts = client.Contact.all(:order => 'Name')

Authentication

Xero uses OAuth to authenticate API clients. The OAuth gem (with minor modification) by John Nunemaker (http://github.com/jnunemaker/twitter) is used in this library. If you've used this before, things will all seem very familar.

There are three methods of authentication detailed below:

All: Consumer Key/Secret

All methods of authentication require your OAuth consumer key and secret. This can be found for your application in the API management console at http://api.xero.com.

Public Applications

Public applications use a 3-legged authorisation process. A user will need to authorise your application against each organisation that you want access to. Your application can have access to many organisations at once by going through the authorisation process for each organisation.

The access token received will expire after 30 minutes. If you want access for longer you will need the user to re-authorise your application.

Authentication occurs in 3 steps:

client = Xeroizer::PublicApplication.new(YOUR_OAUTH_CONSUMER_KEY, YOUR_OAUTH_CONSUMER_SECRET)

# 1. Get a RequestToken from Xero. :oauth_callback is the URL the user will be redirected to
#    after they have authenticated your application.
#
#    Note: The callback URL's domain must match that listed for your application in http://api.xero.com
#          otherwise the user will not be redirected and only be shown the authentication code.
request_token = client.request_token(:oauth_callback => 'http://yourapp.com/oauth/callback')

# 2. Redirect the user to the URL specified by the RequestToken.
#    
#    Note: example uses redirect_to method defined in Rails controllers.
redirect_to request_token.authorize_url

# 3. Exchange RequestToken for AccessToken.
#    This access token will be used for all subsequent requests but it is stored within the client
#    application so you don't have to record it. 
#
#    Note: This example assumes the callback URL is a Rails action.
client.authorize_from_request(request_token.token, request_token.secret, :oauth_verifier => params[:oauth_verifier])

You can now use the client to access the Xero API methods, e.g.

contacts = client.Contact.all

Example Rails Controller

class XeroSessionController < ApplicationController

    before_filter :get_xero_client

    public

        def new
            request_token = @xero_client.request_token(:oauth_callback => 'http://yourapp.com/xero_session/create')
            session[:request_token] = request_token.token
            session[:request_secret] = request_token.secret

            redirect_to request_token.authorize_url
        end

        def create
            @xero_client.authorize_from_request(
                    session[:request_token], 
                    session[:request_secret], 
                    :oauth_verifier => params[:oauth_verifier] )

            session[:xero_auth] = {
                    :access_token => @xero_client.access_token.token,
                    :access_key => @xero_client.access_token.key }

            session.data.delete(:request_token)
            session.data.delete(:request_secret)
        end

        def destroy
            session.data.delete(:xero_auth)
        end

    private

        def get_xero_client
            @xero_client = Xeroizer::PublicApplication.new(YOUR_OAUTH_CONSUMER_KEY, YOUR_OAUTH_CONSUMER_SECRET)

            # Add AccessToken if authorised previously.
            if session[:xero_auth]
                @xero_client.authorize_from_access(
                    session[:xero_auth][:access_token], 
                    session[:xero_auth][:access_key] )
            end
        end
end

Storing AccessToken

You can store the access token/secret pair so you can access the API again without user intervention. Currently these tokens are only valid for 30 minutes and will raise a Xeroizer::OAuth::TokenExpired exception if you try to access the API beyond the token's expiry time.

If you want API access for longer consider creating a PartnerApplication which will allow you to renew tokens.

access_key = client.access_token.token
access_secret = client.access_token.secret

Private Applications

Private applications use a 2-legged authorisation process. When you register your application, you will select the organisation that is authorised to your application. This cannot be changed afterwards, although you can register another private application if you have multiple organisations.

Note: You can only register organisations you are authorised to yourself.

Private applications require a private RSA keypair which is used to sign each request to the API. You can generate this keypair on Mac OSX or Linux with OpenSSL. For example:

openssl genrsa -out privatekey.pem 1024
openssl req -newkey rsa:1024 -x509 -key privatekey.pem -out publickey.cer -days 365
openssl pkcs12 -export -out public_privatekey.pfx -inkey privatekey.pem -in publickey.cer

You need to upload this public_privatekey.pfx file to your private application in http://api.xero.com.

Example usage:

client = Xeroizer::PrivateApplication.new(YOUR_OAUTH_CONSUMER_KEY, YOUR_OAUTH_CONSUMER_SECRET, "/path/to/privatekey.pem")
contacts = client.Contact.all

Partner Applications

Partner applications use a combination of 3-legged authorisation, private key message signing and client-side SSL certificate signing.

Partner applications are only in beta testing via the Xero API and you will need to contact Xero (network@xero.com) to get permission to create a partner application and for them to send you information on obtaining your client-side SSL certificate.

Ruby's OpenSSL library rqeuires the certificate and private key to be extracted from the entrust-client.p12 file downloaded via Xero's instructions. To extract:

openssl pkcs12 -in entrust-client.p12 -clcerts -nokeys -out entrust-cert.pem
openssl pkcs12 -in entrust-client.p12 -nocerts -out entrust-private.pem
openssl rsa -in entrust-private.pem -out entrust-private-nopass.pem

# This last step removes the password that you added to the private key
# when it was exported.

After you have followed the instructions provided by Xero for partner applications and uploaded your certificate you can access the partner application in a similar way to public applications.

Authentication occcurs in 3 steps:

client = Xeroizer::PartnerApplication.new(
                    YOUR_OAUTH_CONSUMER_KEY,
                    YOUR_OAUTH_CONSUMER_SECRET, 
                    "/path/to/privatekey.pem",
                    "/path/to/entrust-cert.pem",
                    "/path/to/entrust-private-nopass.pem"
                    )

# 1. Get a RequestToken from Xero. :oauth_callback is the URL the user will be redirected to
#    after they have authenticated your application.
#
#    Note: The callback URL's domain must match that listed for your application in http://api.xero.com
#          otherwise the user will not be redirected and only be shown the authentication code.
request_token = client.request_token(:oauth_callback => 'http://yourapp.com/oauth/callback')

# 2. Redirect the user to the URL specified by the RequestToken.
#    
#    Note: example uses redirect_to method defined in Rails controllers.
redirect_to request_token.authorize_url

# 3. Exchange RequestToken for AccessToken.
#    This access token will be used for all subsequent requests but it is stored within the client
#    application so you don't have to record it. 
#
#    Note: This example assumes the callback URL is a Rails action.
client.authorize_from_request(request_token.token, request_token.secret, :oauth_verifier => params[:oauth_verifier])

This AccessToken will last for 30 minutes however, when using the partner application API you can renew this token. To be able to renew this token, you need to save the following data from this organisation's AccessToken:

session_handle = client.session_handle
access_key = client.access_token.token
access_secret = client.access_token.secret

Two other interesting attributes of the PartnerApplication client are:

#expires_at*: Time this AccessToken will expire (usually 30 minutes into the future).
*#authorization_expires_at: How long this organisation has authorised you to access their data (usually 365 days into the future).

AccessToken Renewal

Renewal of an access token requires knowledge of the previous access token generated for this organisation. To renew:

# If you still have a client instance.
client.renew_access_token

# If you are renewing from stored token/session details.
client.renew_access_token(access_token, access_secret, session_handle)

This will invalidate the previous token and refresh the access_key and access_secret as specified in the initial authorisation process. You must always know the previous token's details to renew access to this session.

If you lose these details at any stage you can always reauthorise by redirecting the user back to the Xero OAuth gateway.

Retrieving Data

Each of the below record types is implemented within this library. To allow for multiple access tokens to be used at the same time in a single application, the model classes are accessed from the instance of PublicApplication, PrivateApplication or PartnerApplication. All class-level operations occur on this singleton. For example:

xero = Xeroizer::PublicApplication.new(YOUR_OAUTH_CONSUMER_KEY, YOUR_OAUTH_CONSUMER_SECRET)
xero.authorize_from_access(session[:xero_auth][:access_token], session[:xero_auth][:access_key])

contacts = xero.Contact.all(:order => 'Name')

new_contact = xero.Contact.build(:name => 'ABC Development')
saved = new_contact.save

#all([options])

Retrieves list of all records with matching options.

Note: Some records (Invoice, CreditNote) only return summary information for the contact and no line items when returning them this list operation. This library takes care of automatically retrieving the contact and line items from Xero on first access however, this first access has a large performance penalty and will count as an extra query towards your 1,000/day and 60/minute request per organisation limit.

Valid options are:

:modified_since

Records modified after this Time (must be specified in UTC).

:order

Field to order by. Should be formatted as Xero-based field (e.g. 'Name', 'ContactID', etc)

:where

See Where Filters section below.

#first([options])

This is a shortcut method for all and actually runs all however, this method only returns the first entry returned by all and never an array.

#find(id)

Looks up a single record matching id. This ID can either be the internal GUID Xero uses for the record or, in the case of Invoice, CreditNote and Contact records, your own custom reference number used when creating these records.

Where filters

Hash

You can specify find filters by providing the :where option with a hash. For example:

invoices = Xero.Invoice.all(:where => {:type => 'ACCREC', :amount_due_is_not => 0})

will automatically create the Xero string:

Type=="ACCREC"&&AmountDue<>0

The default method for filtering is the equality '==' operator however, these can be overridden by modifying the postfix of the attribute name (as you can see for the :amount_due field above).

\{attribute_name}_is_not will use '<>'
\{attribute_name}_is_greater_than will use '>'
\{attribute_name}_is_greater_than_or_equal_to will use '>='
\{attribute_name}_is_less_than will use '<'
\{attribute_name}_is_less_than_or_equal_to will use '<='

The default is '=='

Note: Currently, the hash-conversion library only allows for AND-based criteria and doesn't take into account associations. For these, please use the custom filter method below.

Custom Xero-formatted string

Xero allows advanced custom filters to be added to a request. The where parameter can reference any XML element in the resulting response, including all nested XML elements.

Example 1: Retrieve all invoices for a specific contact ID:

    invoices = xero.Invoice.all(:where => 'Contact.ContactID.ToString()=="cd09aa49-134d-40fb-a52b-b63c6a91d712"')

Example 2: Retrieve all unpaid ACCREC Invoices against a particular Contact Name:

    invoices = xero.Invoice.all(:where => 'Contact.Name=="Basket Case" && Type=="ACCREC" && AmountDue<>0')

Example 3: Retrieve all Invoices PAID between certain dates

    invoices = xero.Invoice.all(:where => 'FullyPaidOnDate>=DateTime.Parse("2010-01-01T00:00:00")&&FullyPaidOnDate<=DateTime.Parse("2010-01-08T00:00:00")')

Example 4: Retrieve all Bank Accounts:

    accounts = xero.Account.all(:where => 'Type=="BANK"')

Example 5: Retrieve all DELETED or VOIDED Invoices:

    invoices = xero.Invoice.all(:where => 'Status=="VOIDED" OR Status=="DELETED"')

Example 6: Retrieve all contacts with specific text in the contact name:

    contacts = xero.Contact.all(:where => 'Name.Contains("Peter")')
    contacts = xero.Contact.all(:where => 'Name.StartsWith("Pet")')
    contacts = xero.Contact.all(:where => 'Name.EndsWith("er")')

Associations

Records may be associated with each other via two different methods, has_many and belongs_to.

has_many example:

invoice = xero.Invoice.find('cd09aa49-134d-40fb-a52b-b63c6a91d712')
invoice.line_items.each do | line_item |
    puts "Line Description: #{line_item.description}"
end

belongs_to example:

invoice = xero.Invoice.find('cd09aa49-134d-40fb-a52b-b63c6a91d712')
puts "Invoice Contact Name: #{invoice.contact.name}"

Creating/Updating Data

Creating

New records can be created like:

contact = xero.Contact.build(:name => 'Contact Name')
contact.first_name = 'Joe'
contact.last_name = 'Bloggs'
contact.add_address(:type => 'STREET', :line1 => '12 Testing Lane', :city => 'Brisbane')
contact.add_phone(:type => 'DEFAULT', :area_code => '07', :number => '3033 1234')
contact.add_phone(:type => 'MOBILE', :number => '0412 123 456')
contact.save

To add to a has_many association use the add_{association} method. For example:

contact.add_address(:type => 'STREET', :line1 => '12 Testing Lane', :city => 'Brisbane')

To add to a belongs_to association use the build_{association} method. For example:

invoice.build_contact(:name => 'ABC Company')

Updating

If the primary GUID for the record is present, the library will attempt to update the record instead of creating it. It is important that this record is downloaded from the Xero API first before attempting an update. For example:

contact = xero.Contact.find("cd09aa49-134d-40fb-a52b-b63c6a91d712")
contact.name = "Another Name Change"
contact.save

Have a look at the models in lib/xeroizer/models/ to see the valid attributes, associations and minimum validation requirements for each of the record types.

Bulk Creates & Updates

Xero has a hard daily limit on the number of API requests you can make (currently 1,000 requests per account per day). To save on requests, you can batch creates and updates into a single PUT or POST call, like so:

contact1 = xero.Contact.create(some_attributes)
xero.Contact.batch_save do
  contact1.email_address = "foo@bar.com"
  contact2 = xero.Contact.build(some_other_attributes)
  contact3 = xero.Contact.build(some_more_attributes)
end

batch_save will issue one PUT request for all unsaved records built within its block, and one POST request for all existing records that have been altered within its block. If any of the unsaved records aren't valid, it'll return false before sending anything across the wire; otherwise, it returns true.

Errors

If a record doesn't match its internal validation requirements, the #save method will return false and the #errors attribute will be populated with what went wrong.

For example:

contact = xero.Contact.build
saved = contact.save

# contact.errors will contain [[:name, "can't be blank"]]

#errors_for(:attribute_name) is a helper method to return just the errors associated with that attribute. For example:

contact.errors_for(:name) # will contain ["can't be blank"]

If something goes really wrong and the particular validation isn't handled by the internal validators then the library may raise a Xeroizer::ApiException.

Reports

All Xero reports except GST report can be accessed through Xeroizer.

Currently, only generic report access functionality exists. This will be extended to provide a more report-specific version of the data in the future (public submissions are welcome).

Reports are accessed like the following example:

trial_balance = xero.TrialBalance.get(:date => '2011-03-21')

# Array containing report headings.
trial_balance.header.cells.map { | cell | cell.value }

# Report rows by section
trial_balance.sections.each do | section |
    puts "Section Title: #{section.title}"
    section.rows.each do | row |
        puts "\t#{row.cells.map { | cell | cell.value }.join("\t")}"
    end
end

# Summary row (if only one on the report)
trial_balance.summary.cells.map { | cell | cell.value }

# All report rows (including HeaderRow, SectionRow, Row and SummaryRow)
trial_balance.rows.each do | row |
    case row
        when Xeroizer::Report::HeaderRow
            # do something with header

        when Xeroizer::Report::SectionRow
            # do something with section, will need to step into the rows for this section

        when Xeroizer::Report::Row
            # do something for standard report rows

        when Xeroizer::Report::SummaryRow
            # do something for summary rows

    end
end

Xero API Rate Limits

The Xero API imposes the following limits on calls per organisation:

• A limit of 60 API calls in any 60 second period
• A limit of 1000 API calls in any 24 hour period

By default, the library will raise a Xeroizer::OAuth::RateLimitExceeded exception when one of these limits is exceeded.

If required, the library can handle these exceptions internally by sleeping for a configurable number of seconds and then repeating the last request. You can set this option when initializing an application:

# Sleep for 2 seconds every time the rate limit is exceeded.
client = Xeroizer::PublicApplication.new(YOUR_OAUTH_CONSUMER_KEY,
                                         YOUR_OAUTH_CONSUMER_SECRET,
                                         :rate_limit_sleep => 2)

Contributors

Xeroizer was inspired by the https://github.com/tlconnor/xero_gateway gem created by Tim Connor and Nik Wakelin and portions of the networking and authentication code are based completely off this project. Copyright for these components remains held in the name of Tim Connor.