Classic ASP - Attempting to generate OAUTH

[spineh]

Hello,

We've got a legacy system running Classic ASP that we need to get Express payments setup using the REST API.

However whenever we attempt to post using the following:

Set objHTTP = Server.CreateObject("Msxml2.ServerXMLHTTP.6.0")
objHTTP.open "POST", "https://api.sandbox.paypal.com/v1/oauth2/token", false
objHTTP.setRequestHeader "Accept", "application/json"
objHTTP.setRequestHeader "Accept-Language", "en_US"
objHTTP.setRequestHeader "Authorization", "Basic " & Base64Encode("client-id:secret")
objHTTP.send
response.write(objHTTP.responsetext)

We get an error saying a client certificate is required. We've installed the provided to .pem to our server and attempted to assign it to our server using:

objHTTP.setOption(3) = "LOCAL_MACHINE\My\api-3t.sandbox.paypal.com"

However we now get an error saying there's no credentials in the certificate.

Has anyone here successfully got paypal REST API working on classic ASP?

[angelleye]

It looks like maybe you have your endpoints **bleep** up somewhere.  You're showing https://api.sandbox.paypal.com/v1/oauth2/token in your request sample, but then you mention the Certificate mode for authentication (which is the original/old method)...but then you're showing LOCAL_MACHINE\My\api-3t.sandbox.paypal.com.  the api-3t would be used with Signature mode as opposed to Certificate or OAUTH tokens.  So it seems you've got three separate auth methods somehow tied into this thing.  

I don't have an immediate answer for you, but that's where I'd start looking.  

[MSDev]

Spineh: Were you ever able to get the PayPal oAuth token using an XHR call with classic ASP? I know this is a late reply but I'm having the same issue.

Angelleye: I can get data fine from a https URL using classic ASP's MSXML2.ServerXMLHTTP.6.0 or WinHttp.WinHttpRequest.5.1 server objects, but when hitting https://api.sandbox.paypal.com/v1/oauth2/token/ I get the ASP error on the line xmlhttp.Send("grant_type=client_credentials") The error number is -2147012852 and the description "A certificate is required to complete client authentication". This is not the reply from PayPal; it doesn't get that far. Like Spineh I used Basic authentication. If I do specify a certificate like so...

xmlhttp.setOption(3) = "LOCAL_MACHINE\My\{common name}" ' For MSXML2.ServerXMLHTTP.6.0

xmlhttp.setClientCertificate("LOCAL_MACHINE\My\{common name}" ' For WinHttp.WinHttpRequest.5.1

...then I get the error number -2147012710 and the description "The client certificate credentials were not recognized."

Any help would be much appreciated!

[spineh]

Hi MSDev,

Edit: Paypal has helpfully added emojis anywhere you see the happy/sad guy it's ( : S ) (remove spaces) 

We did get this working eventually.

The code is below but needs amending for your setup:

1. CLIENT ID:SECRET ID (This needs to be the IDs from developers.paypal.com of your REST api application. It needs to be base64 encoded first so either write a function for base64 encoding or just use an online tool)
2. Generate payment function is a WIP, just update URL with what endpoint you need to target and include JSON in the POST.

function GenerateBearerToken
Set objHTTP = Server.CreateObject("Msxml2.ServerXMLHTTP.6.0")
objHTTP.open "POST", "https://api.sandbox.paypal.com/v1/oauth2/token", false
objHTTP.setRequestHeader "Accept", "application/json"
objHTTP.setRequestHeader "Accept-Language", "en_US"
objHTTP.setRequestHeader "Authorization", "Basic " & "CLIENT ID:SECRET ID"
objHTTP.send "grant_type=client_credentials"
GenerateBearerToken = objHTTP.responsetext
end function

function GeneratePayment
Set objHTTP = Server.CreateObject("Msxml2.ServerXMLHTTP.6.0")
objHTTP.open "POST", "https://api.sandbox.paypal.com/v1/payment-experience/web-profiles/", false
objHTTP.setRequestHeader "Accept", "application/json"
objHTTP.setRequestHeader "Accept-Language", "en_US"
objHTTP.setRequestHeader "Authorization", "Bearer " & GenerateBearerToken
''objHTTP.send SEND JSON HERE
GeneratePayment = objHTTP.responsetext
end function

[spineh]

Hi MSDev,

Edit: Paypal has helpfully added emojis anywhere you see the happy/sad guy it's ( : S ) (remove spaces) 

We did get this working eventually.

The code is below but needs amending for your setup:

1. CLIENT ID:SECRET ID (This needs to be the IDs from developers.paypal.com of your REST api application. It needs to be base64 encoded first so either write a function for base64 encoding or just use an online tool)
2. Generate payment function is a WIP, just update URL with what endpoint you need to target and include JSON in the POST.

function GenerateBearerToken
Set objHTTP = Server.CreateObject("Msxml2.ServerXMLHTTP.6.0")
objHTTP.open "POST", "https://api.sandbox.paypal.com/v1/oauth2/token", false
objHTTP.setRequestHeader "Accept", "application/json"
objHTTP.setRequestHeader "Accept-Language", "en_US"
objHTTP.setRequestHeader "Authorization", "Basic " & "CLIENT ID:SECRET ID"
objHTTP.send "grant_type=client_credentials"
GenerateBearerToken = objHTTP.responsetext
end function

function GeneratePayment
Set objHTTP = Server.CreateObject("Msxml2.ServerXMLHTTP.6.0")
objHTTP.open "POST", "https://api.sandbox.paypal.com/v1/payment-experience/web-profiles/", false
objHTTP.setRequestHeader "Accept", "application/json"
objHTTP.setRequestHeader "Accept-Language", "en_US"
objHTTP.setRequestHeader "Authorization", "Bearer " & GenerateBearerToken
''objHTTP.send SEND JSON HERE
GeneratePayment = objHTTP.responsetext
end function

[MSDev]

Thanks for your help! That's the code I've been trying so we're on the same page. Here's what I have:

Set xmlhttp = Server.CreateObject("MSXML2.ServerXMLHTTP.6.0")
xmlhttp.Open "POST", "https://api.sandbox.paypal.com/v1/oauth2/token/", false
xmlhttp.SetRequestHeader "Accept", "application/json"
xmlhttp.SetRequestHeader "Accept-Language", "en_US"
xmlhttp.SetRequestHeader "Authorization", "Basic " & Base64Encode(CLIENT_ID & ":" & SECRET)
xmlhttp.Send("grant_type=client_credentials")
Response.write xmlhttp.ResponseText

But I always get the error:

msxml6.dll error '80072f0c'

A certificate is required to complete client authentication

I've confirmed that this is indeed my sandbox client ID and secret from Dashboard > My Apps & Credentials > App Name (type=REST) > SANDBOX API CREDENTIALS. I've also confirmed that the base64 encoding is correct. If I do use the Javascript example here then I can see that it returns the token for my client ID. If I do fetch the token through another means, I still get the same problem when making the call to https://api.sandbox.paypal.com/v1/payments/payment/

I can also make XHR calls to various other HTTPS URLs without issue. It's got me pretty puzzled!

[spineh]

Hi MSDev,

Apologies, I should of read your post first.

I missed out the key ingredient, you need to download and install the paypal specific API certificate.

Follow this guide:

https://www.paypal.com/gb/smarthelp/article/how-do-i-request-api-signature-or-certificate-credential...

Install the certificate then include it in your code like:

objHTTP.setOption(3) = "LOCAL_MACHINE\My\test_api1.hotmail.co.uk"

The client certificate is actually returned by paypal although it looks like a general MS error.

You still need the basic authentication stuff so my code above all still applies just add the setoption(3) to both functions

Kind regards

[MSDev]

Ah, ha! Thanks, spineh. I've got the sandbox certificate downloaded so now I'll try installing it, referencing it in the code (as you included), and seeing if I get success...

[MSDev]

Success! I had some snags with getting the certificate installed and accessible by ASP but I got it working like so:

1. Download the sandbox PayPal certificate through https://www.sandbox.paypal.com > Profile > Profile and settings > My selling tools > API access > NVP/SOAP API integration (Classic).
2. Convert it from PEM to PKCS12 format using:

   openssl pkcs12 -export -inkey PP_sandbox_cert_key.pem -in PP_sandbox_cert_key.pem -out PP_sandbox_cert_key.p12

3. On the server, ran certlm.msc and imported the certificate PP_sandbox_cert_key.p12 unto the 'Personal' folder, which in turns makes if available to the ASP page under LOCAL_MACHINE/My/ so that I could use the line:

   xmlhttp.setOption(3) = "LOCAL_MACHINE\My\ISSUED_TO_NAME"

4. At this point I got the following error on the line :

   msxml6.dll error '80072f9a'
   The client certificate credentials were not recognized.

   Which I fixed through certlm.msc by adding permission for the cert to the IIS application pool (thanks to this answer😞 right-click cert > All Tasks > Manage Private Keys > Add > IIS AppPool\DefaultAppPool
5. Profit!