(Xojo Plugin) Xero OAuth1 Authorization (3-legged)

Demonstrates 3-legged OAuth1 authorization for Xero

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Dim consumerKey As String
consumerKey = "XERO_CONSUMER_KEY"
Dim consumerSecret As String
consumerSecret = "XERO_CONSUMER_SECRET"

Dim requestTokenUrl As String
requestTokenUrl = "https://api.xero.com/oauth/RequestToken"
Dim authorizeUrl As String
authorizeUrl = "https://api.xero.com/oauth/Authorize"
Dim accessTokenUrl As String
accessTokenUrl = "https://api.xero.com/oauth/AccessToken"

// The port number is picked at random. It's some unused port that won't likely conflict with anything else..
Dim callbackUrl As String
callbackUrl = "http://localhost:3017/"
Dim callbackLocalPort As Int32
callbackLocalPort = 3017

// The 1st step in 3-legged OAuth1.0a is to send a POST to the request token URL to obtain an OAuth Request Token
Dim http As New Chilkat.Http
Dim success As Boolean

http.OAuth1 = True
http.OAuthConsumerKey = consumerKey
http.OAuthConsumerSecret = consumerSecret
http.OAuthCallback = callbackUrl

Dim req As New Chilkat.HttpRequest
Dim resp As Chilkat.HttpResponse
resp = http.PostUrlEncoded(requestTokenUrl,req)
If (http.LastMethodSuccess <> True) Then
    System.DebugLog(http.LastErrorText)
    Return
End If

// If successful, the resp.BodyStr contains something like this:  
// oauth_token=-Wa_KwAAAAAAxfEPAAABV8Qar4Q&oauth_token_secret=OfHY4tZBX2HK4f7yIw76WYdvnl99MVGB&oauth_callback_confirmed=true
System.DebugLog(resp.BodyStr)

Dim hashTab As New Chilkat.Hashtable
success = hashTab.AddQueryParams(resp.BodyStr)

Dim requestToken As String
requestToken = hashTab.LookupStr("oauth_token")
Dim requestTokenSecret As String
requestTokenSecret = hashTab.LookupStr("oauth_token_secret")
http.OAuthTokenSecret = requestTokenSecret

System.DebugLog("oauth_token = " + requestToken)
System.DebugLog("oauth_token_secret = " + requestTokenSecret)

// ---------------------------------------------------------------------------
// The next step is to form a URL to send to the authorizeUrl
// This is an HTTP GET that we load into a popup browser.
Dim sbUrlForBrowser As New Chilkat.StringBuilder
success = sbUrlForBrowser.Append(authorizeUrl)
success = sbUrlForBrowser.Append("?oauth_token=")
success = sbUrlForBrowser.Append(requestToken)
Dim urlForBrowser As String
urlForBrowser = sbUrlForBrowser.GetAsString()

// When the urlForBrowser is loaded into a browser, the response from Xero will redirect back to localhost:3017
// We'll need to start a socket that is listening on port 3017 for the callback from the browser.
Dim listenSock As New Chilkat.Socket

Dim backLog As Int32
backLog = 5
success = listenSock.BindAndListen(callbackLocalPort,backLog)
If (success <> True) Then
    System.DebugLog(listenSock.LastErrorText)
    Return
End If

// Wait for the browser's connection in a background thread.
// (We'll send load the URL into the browser following this..)
// Wait a max of 60 seconds before giving up.
Dim maxWaitMs As Int32
maxWaitMs = 60000
Dim task As Chilkat.Task
task = listenSock.AcceptNextConnectionAsync(maxWaitMs)
success = task.Run()

//  At this point, your application should load the URL in a browser.
//  For example,
//  in C#:  System.Diagnostics.Process.Start(urlForBrowser);
//  in Java: Desktop.getDesktop().browse(new URI(urlForBrowser));
//  in VBScript: Set wsh=WScript.CreateObject("WScript.Shell")
//               wsh.Run urlForBrowser
// in Xojo: ShowURL(url)  (see http://docs.xojo.com/index.php/ShowURL)
// in Dataflex: Runprogram Background "c:\Program Files\Internet Explorer\iexplore.exe" sUrl        
//  The Xero account owner would interactively accept or deny the authorization request.

//  Add the code to load the url in a web browser here...
//  Add the code to load the url in a web browser here...
//  Add the code to load the url in a web browser here...
// System.Diagnostics.Process.Start(urlForBrowser);

// Wait for the listenSock's task to complete.
success = task.Wait(maxWaitMs)
If (Not success Or (task.StatusInt <> 7) Or (task.TaskSuccess <> True)) Then
    If (Not success) Then
        // The task.LastErrorText applies to the Wait method call.
        System.DebugLog(task.LastErrorText)
    Else
        // The ResultErrorText applies to the underlying task method call (i.e. the AcceptNextConnection)
        System.DebugLog(task.Status)
        System.DebugLog(task.ResultErrorText)
    End If

    Return
End If

// If we get to this point, the connection from the browser arrived and was accepted.

// We no longer need the listen socket...
// Stop listening on port 3017.
success = listenSock.Close(10)

// First get the connected socket.
Dim sock As New Chilkat.Socket
success = sock.LoadTaskResult(task)

// Read the start line of the request..
Dim startLine As String
startLine = sock.ReceiveUntilMatch(EndOfLine.Windows)
If (sock.LastMethodSuccess <> True) Then
    System.DebugLog(sock.LastErrorText)
    Return
End If

// Read the request header.
Dim requestHeader As String
requestHeader = sock.ReceiveUntilMatch(EndOfLine.Windows + EndOfLine.Windows)
If (sock.LastMethodSuccess <> True) Then
    System.DebugLog(sock.LastErrorText)
    Return
End If

// The browser SHOULD be sending us a GET request, and therefore there is no body to the request.
// Once the request header is received, we have all of it.
// We can now send our HTTP response.
Dim sbResponseHtml As New Chilkat.StringBuilder
success = sbResponseHtml.Append("<html><body><p>Chilkat thanks you!</b></body</html>")

Dim sbResponse As New Chilkat.StringBuilder
success = sbResponse.Append("HTTP/1.1 200 OK" + EndOfLine.Windows)
success = sbResponse.Append("Content-Length: ")
success = sbResponse.AppendInt(sbResponseHtml.Length)
success = sbResponse.Append(EndOfLine.Windows)
success = sbResponse.Append("Content-Type: text/html" + EndOfLine.Windows)
success = sbResponse.Append(EndOfLine.Windows)
success = sbResponse.AppendSb(sbResponseHtml)

success = sock.SendString(sbResponse.GetAsString())
success = sock.Close(50)

// The information we need is in the startLine.
// For example, the startLine will look something like this:
//  GET /?oauth_token=abcdRQAAZZAAxfBBAAABVabcd_k&oauth_verifier=9rdOq5abcdCe6cn8M3jabcdj3Eabcd&org=mUkIZabcdKEababcd189t0 HTTP/1.1
Dim sbStartLine As New Chilkat.StringBuilder
success = sbStartLine.Append(startLine)
Dim numReplacements As Int32
numReplacements = sbStartLine.Replace("GET /?","")
numReplacements = sbStartLine.Replace(" HTTP/1.1","")
success = sbStartLine.Trim()

// oauth_token=abcdRQAAZZAAxfBBAAABVabcd_k&oauth_verifier=9rdOq5abcdCe6cn8M3jabcdj3Eabcd&org=mUkIZabcdKEababcd189t0
System.DebugLog("startline: " + sbStartLine.GetAsString())

hashTab.Clear 
success = hashTab.AddQueryParams(sbStartLine.GetAsString())

requestToken = hashTab.LookupStr("oauth_token")
Dim authVerifier As String
authVerifier = hashTab.LookupStr("oauth_verifier")

// ------------------------------------------------------------------------------
// Finally , we must exchange the OAuth Request Token for an OAuth Access Token.

http.OAuthToken = requestToken
http.OAuthVerifier = authVerifier
resp = http.PostUrlEncoded(accessTokenUrl,req)
If (http.LastMethodSuccess <> True) Then
    System.DebugLog(http.LastErrorText)
    Return
End If

// Make sure a successful response was received.
If (resp.StatusCode <> 200) Then
    System.DebugLog(resp.StatusLine)
    System.DebugLog(resp.Header)
    System.DebugLog(resp.BodyStr)
    Return
End If

// If successful, the resp.BodyStr contains something like this:
// oauth_token=85123455-fF41296Bi3daM8eCo9Y5vZabcdxXpRv864plYPOjr&oauth_token_secret=afiYJOgabcdSfGae7BDvJVVTwys8fUGpra5guZxbmFBZo&oauth_expires_in=1800&xero_org_muid=abcdecNhPKabcdNjz189t0
System.DebugLog(resp.BodyStr)

hashTab.Clear 
success = hashTab.AddQueryParams(resp.BodyStr)

Dim accessToken As String
accessToken = hashTab.LookupStr("oauth_token")
Dim accessTokenSecret As String
accessTokenSecret = hashTab.LookupStr("oauth_token_secret")
Dim orgMuid As String
orgMuid = hashTab.LookupStr("xero_org_muid")
Dim expiresIn As String
expiresIn = hashTab.LookupStr("oauth_expires_in")

// The access token + secret is what should be saved and used for
// subsequent REST API calls.
System.DebugLog("Access Token = " + accessToken)
System.DebugLog("Access Token Secret = " + accessTokenSecret)
System.DebugLog("xero_org_muid = " + orgMuid)
System.DebugLog("oauth_expires_in  = " + expiresIn)

// Save this access token for future calls.
// Just in case we need xero_org_muid and oauth_expires_in, save those also..
Dim json As New Chilkat.JsonObject
success = json.AppendString("oauth_token",accessToken)
success = json.AppendString("oauth_token_secret",accessTokenSecret)
success = json.AppendString("xero_org_muid",orgMuid)
success = json.AppendString("oauth_expires_in",expiresIn)

Dim fac As New Chilkat.FileAccess
success = fac.WriteEntireTextFile("qa_data/tokens/xero.json",json.Emit(),"utf-8",False)

System.DebugLog("Success.")