REST calls where seperate Auth token must be requested (+ a dash of AJAX Client Script)

Greetings all,

In some outbound REST calls, basic auth may not be sufficient. I’ve had a few requirements where a seperate request must first be made to get an auth token, and wanted to share the solution I wrote.

Our example today is CloudBolt, and though the specifics may not apply same way everytime, the concept is universal. I’ve seen this in a number of other services as well.

Let’s review what we will accomplish today

• Create an auth POST to obtain a token
• Pass that token into a GET/POST to be utilized
• Create a Script Include so that we can seemlessly execute this two-step process anywhere in the platform
• Call the GET API on client script during a catalog order form with AJAX to populate a dropdown list dynamically

Outbound REST Message I: Auth

I want to ask CloudBolt to do something like spin up a server. For me to make that API call, I first must perform a seperate API call all together to get an Auth Token.

Let’s navigate to System Web Services > Outbound > REST Message within ServiceNow and get started.

Create a new REST Message called CloudBolt. Provide in the HTTP Request Headers:
Accept : application/json
X-CSRFToken : Provided by your CloudBolt admin (if directed)

Your CloudBolt admin will also provide a basic Auth username/password. Don’t put it here yet.

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Now in the related list below, create a new HTTP Method: [Endpoint may vary, consult your CloudBolt admin]

Name = Auth
HTTP Method = POST
Endpoint = https://cloudmanager.[YourCompany]/api/v2/api-token-auth
Authentication Type = Basic
Content = {“username”:”USERNAME“,”password”:”PASSWORD“}

Save it and hit Test, you should get back a Response (Fake example)

{"token":"eyJhFeef34DFG9ydEBpaGcuY29tIiwiZXhwIjoxNTI0MTcwNjMwfQ.tetMp3jjXlbRRPCCF6zacspxfdDwRA4hrbvDWsogqe4"}

That token should be good for a bit so copy to notepad.

 

Outbound REST Message II: Desired Function

In this example, I am going to GET a list of groups from CloudBolt to later populate into a Catalog Item Dropdown list.

Using same REST Message for CloudBolt, I will create a second HTTP Method:

Name = CBL-Groups
HTTP Method = GET
Endpoint = https://cloudmanager.[YourCompany]/api/v2/groups/?page_size=1000
HTTP Request Headers :
Accept : application/json
Content-Type : application/json
Authorization : Bearer ${token}

Create new Variable Substituation with:
Name = token
Test value = paste the long Token string obtained prior

The key here is that a variable with be used where we pass the token

This way, we can dynamically insert new tokens on the fly. Hit Test and watch the magic happen! I hope.. Maybe pull that Auth token again.

 

Tie them together in a Script Include

To chain these two APIs together, we will build a new Script Include

In our use case, we will call this from Client Script so first:
Name = CloudBoltAPI
Client callable = True

Copy the code here

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Using AJAX to pull multi-step API

I’ll be calling both APIs with one Ajax call on a Catalog based Client Side Script. My goal is to get the list of groups from CloudBolt and populate a dropdown list.

Copy the code here

 

Conclusion

Wether you came here for multi-step auth API how-to or Client Side AJAX API call, I hope this was clear and helpful. If you have any questions, feel free to comment and share!