(Visual FoxPro) Xero API through an HTTP Proxy

This example demonstrates connecting through an HTTP proxy w/ 2-legged OAuth for a Xero private application.

This example requires Chilkat v9.5.0.64 or later

Chilkat ActiveX Downloads ActiveX for 32-bit and 64-bit Windows

LOCAL loRest
LOCAL loSocket
LOCAL lnBTls
LOCAL lnPort
LOCAL lnMaxWaitMs
LOCAL lnSuccess
LOCAL lcConsumerKey
LOCAL lcConsumerSecret
LOCAL loPfx
LOCAL loPrivKeyFromPfx
LOCAL loPrivKeyFromPem
LOCAL loOauth1
LOCAL loSbXml
LOCAL lnBAutoTrim
LOCAL loXml
LOCAL lnRecordCount
LOCAL i

* This example requires Chilkat v9.5.0.64 or later

* This sample code would typically be placed in a subroutine or function
* where the rest object is passed by reference.
* It does the OAuth1 setup and makes the initial connection.
* For versions of Chilkat < 10.0.0, use CreateObject('Chilkat_9_5_0.Rest')
loRest = CreateObject('Chilkat.Rest')

* Connect to the Xero server through an HTTP proxy, and then tell the REST object
* to use the socket connection.
* For versions of Chilkat < 10.0.0, use CreateObject('Chilkat_9_5_0.Socket')
loSocket = CreateObject('Chilkat.Socket')

* Set the HTTP proxy domain or IP address, and port.
loSocket.HttpProxyHostname = "192.168.1.100"
loSocket.HttpProxyPort = 8088
loSocket.HttpProxyForHttp = 1

* Connect through the HTTP proxy..
lnBTls = 1
lnPort = 443
lnMaxWaitMs = 5000
lnSuccess = loSocket.Connect("api.xero.com",lnPort,lnBTls,lnMaxWaitMs)
IF (lnSuccess <> 1) THEN
    ? "Connect Failure Error Code: " + STR(loSocket.ConnectFailReason)
    ? loSocket.LastErrorText
    RELEASE loRest
    RELEASE loSocket
    CANCEL
ENDIF

* Use the HTTP proxied TLS connection:
lnSuccess = loRest.UseConnection(loSocket,1)
IF (lnSuccess <> 1) THEN
    ? loRest.LastErrorText
    RELEASE loRest
    RELEASE loSocket
    CANCEL
ENDIF

* OK, we're connected.  
* The UseConnection method has an internal reference to the underlying/internal socket.
* The application can does not need to keep its socket object in existence.
* -----------------------------------------------------------------
* Now setup the OAuth1 authenticator..

lcConsumerKey = "XERO_PRIVATE_APP_KEY"
lcConsumerSecret = "XERO_PRIVATE_APP_SECRET"

* Let's get our private key from our PFX (password protected), or the PEM (unprotected).
* You can decide which to use.  Either is OK, although I would recommend keeping your
* private keys in a PFX and not in an unprotected PEM.
* For versions of Chilkat < 10.0.0, use CreateObject('Chilkat_9_5_0.Pfx')
loPfx = CreateObject('Chilkat.Pfx')
lnSuccess = loPfx.LoadPfxFile("qa_data/certs/xero_private_app/public_privatekey.pfx","PFX_PASSWORD")
IF (lnSuccess <> 1) THEN
    ? loPfx.LastErrorText
    RELEASE loRest
    RELEASE loSocket
    RELEASE loPfx
    CANCEL
ENDIF

loPrivKeyFromPfx = loPfx.GetPrivateKey(0)
IF (loPfx.LastMethodSuccess <> 1) THEN
    ? loPfx.LastErrorText
    RELEASE loRest
    RELEASE loSocket
    RELEASE loPfx
    CANCEL
ENDIF

* Or we can load from a PEM..
* For versions of Chilkat < 10.0.0, use CreateObject('Chilkat_9_5_0.PrivateKey')
loPrivKeyFromPem = CreateObject('Chilkat.PrivateKey')
lnSuccess = loPrivKeyFromPem.LoadPemFile("qa_data/certs/xero_private_app/privatekey.pem")
IF (lnSuccess <> 1) THEN
    ? loPrivKeyFromPem.LastErrorText
    RELEASE loRest
    RELEASE loSocket
    RELEASE loPfx
    RELEASE loPrivKeyFromPem
    CANCEL
ENDIF

* Note: There are many other means for loading a private key, including
* from other formats and directly from memory (i.e. not file-based).

* For versions of Chilkat < 10.0.0, use CreateObject('Chilkat_9_5_0.OAuth1')
loOauth1 = CreateObject('Chilkat.OAuth1')
loOauth1.ConsumerKey = lcConsumerKey
loOauth1.ConsumerSecret = lcConsumerSecret
loOauth1.Token = lcConsumerKey
loOauth1.TokenSecret = lcConsumerSecret
loOauth1.SignatureMethod = "RSA-SHA1"
loOauth1.SetRsaKey(loPrivKeyFromPfx)
RELEASE loPrivKeyFromPfx

* Install the OAuth1 authenticator.
loRest.SetAuthOAuth1(loOauth1,0)

? "OK, the Xero OAuth1 is initialized and the REST object is ready to make REST API calls.."

* -----------------------------------------------------------------
* Make a call to verify that OAuth1 through an HTTP proxy works..

* Get the full list of contacts.
* For versions of Chilkat < 10.0.0, use CreateObject('Chilkat_9_5_0.StringBuilder')
loSbXml = CreateObject('Chilkat.StringBuilder')
lnSuccess = loRest.FullRequestNoBodySb("GET","/api.xro/2.0/Contacts",loSbXml)
IF (lnSuccess <> 1) THEN
    ? loRest.LastErrorText
    RELEASE loRest
    RELEASE loSocket
    RELEASE loPfx
    RELEASE loPrivKeyFromPem
    RELEASE loOauth1
    RELEASE loSbXml
    CANCEL
ENDIF

* A 200 response is expected for actual success.
IF (loRest.ResponseStatusCode <> 200) THEN
    ? loSbXml.GetAsString()
    RELEASE loRest
    RELEASE loSocket
    RELEASE loPfx
    RELEASE loPrivKeyFromPem
    RELEASE loOauth1
    RELEASE loSbXml
    CANCEL
ENDIF

* Iterate over the contacts..
lnBAutoTrim = 0
* For versions of Chilkat < 10.0.0, use CreateObject('Chilkat_9_5_0.Xml')
loXml = CreateObject('Chilkat.Xml')
loXml.LoadSb(loSbXml,lnBAutoTrim)
loXml.SaveXml("qa_cache/xero_contacts.xml")

* How many records exist?
lnRecordCount = loXml.NumChildrenAt("Contacts")
? "numRecords = " + STR(lnRecordCount)

i = 0
DO WHILE i < lnRecordCount
    loXml.I = i
    ? "ContactID: " + loXml.GetChildContent("Contacts|Contact[i]|ContactID")
    i = i + 1
ENDDO

RELEASE loRest
RELEASE loSocket
RELEASE loPfx
RELEASE loPrivKeyFromPem
RELEASE loOauth1
RELEASE loSbXml
RELEASE loXml