Web API to receive values from external system

Question

I need to receive the values from external system to update into Appian database. So i have used start process in web api to get those values and update accordingly. Through postman i was able to start the process with provided values from external system but when i'm try to trigger from mule service it not able to trigger and sometimes it shows 401 authentication problem. User who try to start the process is also available in appian environment. Please help on this how get those data from mule service.

aloks0189 · Accepted Answer

gangatharan FIrst of all we are not supposed to get the HTML Page as a response when you are making a call to an API. This can happen in only following cases: 1. Mule system might be trying to open the endpoint URL (either internally or via some User Intercation). Let's say, i have a link and upon click i need to Authenticate Appian, so instead of Authenticating via API Call it might be trying to Open this URL, if so, you will expect an HTML Response. May i know, are you passing preemptive as true. 2. Are you working with Mule 3.7.x or the previous version, because The new HTTP Requester in Mule ESB 3.6.0 does not support preemptive authentication but it does starting from version Mule 3.7.x 3. Your Endpoint might have some Typo (means some mistake in it's endpoint url) so you need to cross check that as well. I believe point- 1 & 2 might be the actual reason behind the issue you are currently facing. Resolution: --------------------- If you are working with lower version of Mule (i.e. less than 3.7.x ) then i recommend upgrading your Mule System. Hope this will help.

aloks0189 · Answer

Hi gangatharan couple of factors to consider here, in order to resolve this issue. 
 1. You must have a service account/user in your Appian environment of type Basic User 
 2. Navigate to WEB-API security, and provide Viewer permission to this user or his respective group (recommend) 
 3. Provide Viewer permission to this user or his respective group (recommend) under process model security (which will be triggered by this Web - API) 
 4. Configure this API endpoint in mule service, and enable preemptive authentication and the mode of authentication should be Http Basic Authentication (where you need to provide this Appian service account/user and his respective password) 
 5. Provide the body content for your request, as it's not a GET call. 
 6. Test your request. 
 If you have followed above mentioned steps in sequence, you should be able to communicate to Appian. 
 Hope this helps.

gangatharan · Answer

Thanks it got worked. The issue is from mule side where they need to enable preemptive authorization.

gangatharan · Answer

Thanks it worked by giving preemptive authorization as enabled