An extension of the XeroOAuth-PHP public.php file demonstrating the complete OAuth process along with creating an invoice

xerooauth_public_demo.php

<?php
/**
 * Xero invoice creation demo
 * 
 * Written to help provide an answer to this Stack Overflow question: http://stackoverflow.com/q/26250530/628267
 */
 
// Includes and defines
include 'XeroOAuth-PHP/lib/XeroOAuth.php';

define ( "XRO_APP_TYPE", "Public" );
define ( "OAUTH_CALLBACK", XeroOAuth::php_self () );
$useragent = "Xero-OAuth-PHP Public";

$signatures = array (
        'consumer_key' => 'key',
        'shared_secret' => 'secret',
		// API versions
		'core_version' => '2.0',
		'payroll_version' => '1.0',
		'file_version' => '1.0' 
);

$XeroOAuth = new XeroOAuth ( array_merge ( array (
		'application_type' => XRO_APP_TYPE,
		'oauth_callback' => OAUTH_CALLBACK,
		'user_agent' => $useragent 
), $signatures ) );

// Make sure the config is all ok
$initialCheck = $XeroOAuth->diagnostics ();
$checkErrors = count ( $initialCheck );
if ($checkErrors > 0) {
	foreach ( $initialCheck as $check ) {
		echo 'Error: ' . $check . '<br>';
        die();
	}
} 
	
$here = XeroOAuth::php_self ();
session_start ();
$oauthSession = retrieveSession ();

// No oauth details, start the OAuth process
if ($oauthSession === false && !isset ( $_REQUEST ['oauth_verifier'])) {
    
    // Fetch an OAuth request token (step 1)
    $params = array (
        'oauth_callback' => OAUTH_CALLBACK 
    );    
    $response = $XeroOAuth->request ( 'GET', $XeroOAuth->url ( 'RequestToken', '' ), $params );
    
    if ($XeroOAuth->response ['code'] == 200) {		
        
        // Redirect to Xero so the user can authorise the app (step 2)	
        $scope = 'payroll.payrollcalendars,payroll.superfunds,payroll.payruns,payroll.payslip,payroll.employees';
        $_SESSION ['oauth'] = $XeroOAuth->extract_params ( $XeroOAuth->response ['response'] );		
        
        $authurl = $XeroOAuth->url ( "Authorize", '' ) . "?oauth_token={$_SESSION['oauth']['oauth_token']}&scope=" . $scope;        
        echo '<p>To authorise this application, go to this URL: <a href="' . $authurl . '">' . $authurl . '</a></p>';
        
    } else {
        echo 'Failed to get request token:<br>';
        outputError ( $XeroOAuth );
    }
    
// Swap the request token for an access token (step 3)
} elseif (isset ( $_REQUEST ['oauth_verifier'] )) {
    $XeroOAuth->config['access_token'] = $_SESSION ['oauth'] ['oauth_token'];
    $XeroOAuth->config['access_token_secret'] = $_SESSION ['oauth'] ['oauth_token_secret'];

    $code = $XeroOAuth->request ( 'GET', $XeroOAuth->url ( 'AccessToken', '' ), array (
        'oauth_verifier' => $_REQUEST ['oauth_verifier'],
        'oauth_token' => $_REQUEST ['oauth_token'] 
    ) );
    
    if ($XeroOAuth->response ['code'] == 200) {
        // Store the access token in the session and refresh the page.
        $response = $XeroOAuth->extract_params ( $XeroOAuth->response ['response'] );
        $session = persistSession ( $response );			
        unset ( $_SESSION ['oauth'] );
        header ( "Location: {$here}" );
    } else {
        echo 'Failed to get access token:<br>';
        outputError ( $XeroOAuth );
    }

// OAuth token found, lets use it!
} else {

    $XeroOAuth->config ['access_token'] = $oauthSession ['oauth_token'];
    $XeroOAuth->config ['access_token_secret'] = $oauthSession ['oauth_token_secret']; 
    
    $xml = "<Invoices>    
            <Invoice>    
            <Type>ACCREC</Type>    
            <Contact>        
            <Name>Ima Test</Name>        
            </Contact>        
            <Date>2014-05-13T00:00:00</Date>        
            <DueDate>".date('c')."</DueDate>    
            <LineAmountTypes>Exclusive</LineAmountTypes>    
            <LineItems>    
            <LineItem>    
            <Description>Demo invoice</Description>    
            <Quantity>4.3400</Quantity>    
            <UnitAmount>395.00</UnitAmount>    
            <AccountCode>200</AccountCode>    
            </LineItem>    
            </LineItems>    
            </Invoice>    
            </Invoices>";
    
    $XeroOAuth->request('POST', $XeroOAuth->url('Invoices', 'core'),  array(), $xml);
    
    if ($XeroOAuth->response ['code'] == 200) {
        // Invoice created
        $xmlResponse = new SimpleXMLElement($XeroOAuth->response ['response']);
        echo "Invoice created<br><br> Result: {$xmlResponse->Status}<br>";
        echo "Invoice ID: {$xmlResponse->Id}<br>";
        echo "Invoice Number: {$xmlResponse->Invoices->Invoice->InvoiceNumber}<br>";
    } else {            
        $response = $XeroOAuth->extract_params ( $XeroOAuth->response ['response']);            
        // Public tokens only last 30 mins. 
        if ($response['oauth_problem'] == 'token_expired') {
            unset($_SESSION['access_token']);
            echo 'Expired session - <a href="?">restart the oauth process</a>';
        } else {        
            echo 'Failed to create invoice:<br>';
            outputError ( $XeroOAuth );
        }
    }
    
}

// Handy functions from the XeroAPI test class

function retrieveSession()
{
    if (isset($_SESSION['access_token'])) {
        $response['oauth_token'] = $_SESSION['access_token'];
        $response['oauth_token_secret'] = $_SESSION['oauth_token_secret'];
        if(isset($_SESSION['session_handle'])) 
            $response['oauth_session_handle'] = $_SESSION['session_handle'];
        return $response;
    } else {
        return false;
    }
}

function persistSession($response)
{
    if (isset($response)) {
        $_SESSION['access_token'] = $response['oauth_token'];
        $_SESSION['oauth_token_secret'] = $response['oauth_token_secret'];
        if(isset($response['oauth_session_handle'])) $_SESSION['session_handle'] = $response['oauth_session_handle'];
        var_dump($response);
    } else {
        return false;
    }
}

function outputError($XeroOAuth)
{
    echo 'Error: ' . $XeroOAuth->response['response'] . PHP_EOL;
    pr($XeroOAuth);
}

function pr($obj)
{
    if (!is_cli())
        echo '<pre style="word-wrap: break-word">';
    if (is_object($obj))
        print_r($obj);
    elseif (is_array($obj))
        print_r($obj);
    else
        echo $obj;
    if (!is_cli())
        echo '</pre>';
}

Thank you for doing work for lazy XERO SOB! XERO guys are not capable of writing simple step-by-step tutorial scripts but wrote tons and tons of useless marketing sh t. No wonder even QuickBooks dinosaurs are beating them. Can you recommend online accounting system written by responsible company? Tired of wasting my time on just how to connect to their sh t.