(Visual FoxPro) Xero API through an SSH Tunnel

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

Note: This example requires Chilkat v11.0.0 or greater.

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LOCAL lnSuccess
LOCAL loTunnel
LOCAL lcSshHostname
LOCAL lnSshPort
LOCAL loRest
LOCAL lnBTls
LOCAL lnPort
LOCAL lnMaxWaitMs
LOCAL loChannel
LOCAL lcConsumerKey
LOCAL lcConsumerSecret
LOCAL loPfx
LOCAL loPrivKeyFromPfx
LOCAL loPrivKeyFromPem
LOCAL loOauth1
LOCAL loSbXml
LOCAL lnBAutoTrim
LOCAL loXml
LOCAL lnRecordCount
LOCAL i

lnSuccess = 0

loTunnel = CreateObject('Chilkat.Socket')

lcSshHostname = "sftp.example.com"
lnSshPort = 22

* Connect to an SSH server and establish the SSH tunnel:
lnSuccess = loTunnel.SshOpenTunnel(lcSshHostname,lnSshPort)
IF (lnSuccess = 0) THEN
    ? loTunnel.LastErrorText
    RELEASE loTunnel
    CANCEL
ENDIF

* Authenticate with the SSH server via a login/password
* or with a public key.
* This example demonstrates SSH password authentication.
lnSuccess = loTunnel.SshAuthenticatePw("mySshLogin","mySshPassword")
IF (lnSuccess = 0) THEN
    ? loTunnel.LastErrorText
    RELEASE loTunnel
    CANCEL
ENDIF

*  OK, the SSH tunnel is setup.  Now open a channel within the tunnel.
*  (Any number of channels may be created from the same SSH tunnel.
*  Multiple channels may coexist at the same time.)

* 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.
loRest = CreateObject('Chilkat.Rest')

lnBTls = 1
lnPort = 443
lnMaxWaitMs = 7000

* This returns a socket object that is a single channel within the SSH tunnel.
loChannel = CreateObject('Chilkat.Socket')
lnSuccess = loTunnel.SshNewChannel("api.xero.com",lnPort,lnBTls,lnMaxWaitMs,loChannel)
IF (lnSuccess = 0) THEN
    ? loTunnel.LastErrorText
    RELEASE loTunnel
    RELEASE loRest
    RELEASE loChannel
    CANCEL
ENDIF

* Use the connection.  (This connection is a TLS running on an SSH channel through an SSH tunnel.
* In other words, TLS is wrapped within the SSH tunnel.)
lnSuccess = loRest.UseConnection(loChannel,1)
IF (lnSuccess <> 1) THEN
    ? loRest.LastErrorText
    RELEASE loTunnel
    RELEASE loRest
    RELEASE loChannel
    CANCEL
ENDIF

* OK, we're connected.  
* -----------------------------------------------------------------
* 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.
loPfx = CreateObject('Chilkat.Pfx')
lnSuccess = loPfx.LoadPfxFile("qa_data/certs/xero_private_app/public_privatekey.pfx","PFX_PASSWORD")
IF (lnSuccess = 0) THEN
    ? loPfx.LastErrorText
    RELEASE loTunnel
    RELEASE loRest
    RELEASE loChannel
    RELEASE loPfx
    CANCEL
ENDIF

loPrivKeyFromPfx = CreateObject('Chilkat.PrivateKey')
lnSuccess = loPfx.PrivateKeyAt(0,loPrivKeyFromPfx)
IF (lnSuccess = 0) THEN
    ? loPfx.LastErrorText
    RELEASE loTunnel
    RELEASE loRest
    RELEASE loChannel
    RELEASE loPfx
    RELEASE loPrivKeyFromPfx
    CANCEL
ENDIF

* Or we can load from a PEM..
loPrivKeyFromPem = CreateObject('Chilkat.PrivateKey')
lnSuccess = loPrivKeyFromPem.LoadPemFile("qa_data/certs/xero_private_app/privatekey.pem")
IF (lnSuccess = 0) THEN
    ? loPrivKeyFromPem.LastErrorText
    RELEASE loTunnel
    RELEASE loRest
    RELEASE loChannel
    RELEASE loPfx
    RELEASE loPrivKeyFromPfx
    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).

loOauth1 = CreateObject('Chilkat.OAuth1')
loOauth1.ConsumerKey = lcConsumerKey
loOauth1.ConsumerSecret = lcConsumerSecret
loOauth1.Token = lcConsumerKey
loOauth1.TokenSecret = lcConsumerSecret
loOauth1.SignatureMethod = "RSA-SHA1"
loOauth1.SetRsaKey(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.
loSbXml = CreateObject('Chilkat.StringBuilder')
lnSuccess = loRest.FullRequestNoBodySb("GET","/api.xro/2.0/Contacts",loSbXml)
IF (lnSuccess = 0) THEN
    ? loRest.LastErrorText
    RELEASE loTunnel
    RELEASE loRest
    RELEASE loChannel
    RELEASE loPfx
    RELEASE loPrivKeyFromPfx
    RELEASE loPrivKeyFromPem
    RELEASE loOauth1
    RELEASE loSbXml
    CANCEL
ENDIF

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

* Iterate over the contacts..
lnBAutoTrim = 0
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 loTunnel
RELEASE loRest
RELEASE loChannel
RELEASE loPfx
RELEASE loPrivKeyFromPfx
RELEASE loPrivKeyFromPem
RELEASE loOauth1
RELEASE loSbXml
RELEASE loXml