Retrieving data from a site through a secured proxy - vba

Question

My client will access my company's site to retrieve data information, using a sub I am working on. This has to be done using a secured proxy, since his company blocks access to some sites. I can't test my sub on his computer and obviously he cannot send the proxy information (ie.:Username, passoword, ip, port...)
Sub login_sub()
url = "http://localhost/php004/loginExcelAddin.php?username=" + username + "&password=" + password
Dim httpObject As Object
Dim response As String
Set httpObject = CreateObject("WinHttp.WinHttpRequest.5.1")
httpObject.Open "GET", url, False
httpObject.SetProxy HTTPREQUEST_PROXYSETTING_PROXY, proxyIP + ":" + proxyPortNumber
httpObject.send
response = httpObject.responseText
On Error GoTo errorHandler
If response = True Then
loggedIn = True
MsgBox "You are logged in"
End If
Application.Calculate
Exit Sub
errorHandler:
MsgBox "Login has failed"
End Sub
(Username, password, proxyPortNumber, proxyIP are public variables filled in a form)
I am struggled with this issue for a while. Anyone could tell me if I am going to the right direction, can I send this code for the client?
Thanks

Answer 1

Ah, I've been through this before many times in my career. From a test strategy perspective (rather than a review of your code above), there are several possible combinations of ways to test all this out:
The client's IT department should be able to provide you with specifications on how their proxy expects client identification information to be included in the outbound request. Some proxies may use alternative authentication information data in the request headers; you need to know exactly how the client's proxy requires the authentication data to be passed (this can get troublesome on Enterprise proxies that may use Active Directory/LDAP as intermediaries).
The ideal first stage of testing is to setup inside your own company a test authenticating proxy in as close as possible the same make, version, and configuration as the client's. Put your Excel code onto a laptop, and connect the laptop to the "outside" of this test proxy. This will allow you to test the code to work out bugs with accessing a similar proxy under your control.
Of course, its quite possible that the client's proxy may not behave quite like your test proxy, so even after doing step 2, there may still be problems once you give it to the client. If the client is allowed to use window sharing services like WebEx, you could then set up a WebEx session with the client, and have them share their screen with you while they are using your code for the first time. If it fails, you can talk them though a debugging session with Excel's debugger while you are watching the debugging results.
3a. If the client's IT Dept will allow a more comprehensive sharing tool that allows YOU to remotely control the client's desktop (while they are watching) that would even be more ideal. But if the client's IT Dept is already doing outbound proxying, they are likely too paranoid to allow this.
If a WebEx-like session is not allowed, then you could add diagnostic outputs into a log file which they could then send you, or verbally tell you in a telecon. This is not an optimal way to accomplish the debugging.
4a. Again if WebEx-like method is not allowed, but if the client has an Excel expert and an IT expert, you can get them to do the testing with you on a telecon. Again not optimal but is better than 3 because you are not talking with a clueless client.
Finally and worst-case, you may have to travel to the client's site to do final testing on their own computers (under of course the supervision of the client).