Call POST API from GET API

Question

Hi All, 
 I have two APIs right now. POST webAPI and GET Webapi. 
 --POST API is taking two query params as input, doing a start process and returning some url in its body. 
 --In GET Api i want to fetch that url from POST APIs body. How can I pass the params to POST Api from my GET API to fetch the url as response in GET API? 
 Here is my current implementation in GET API: 
 a!localVariables(
 local!httpRequestBody:http!request.queryParameters,
 local!FormId: if(
 rule!GEN_IsNull(local!httpRequestBody),
 null,
 local!httpRequestBody.FormId
 ),
 local!formToLaunchParameters_txt: if(
 rule!GEN_IsNull(local!httpRequestBody),
 null,
 local!httpRequestBody.formToLaunchParameters_txt
 ),
 if(
 or(
 rule!GEN_IsNull(local!FormId),
 rule!GEN_IsNull(local!formToLaunchParameters_txt)
 ),
 a!httpResponse(
 statusCode: 500,
 headers: a!httpHeader(
 name:"Content-Type",
 value:"application/json"
 ),
 body:a!toJson(
 {
 error:"FormId or KeyInstn is missing"
 }
 )
 ),
 a!httpResponse(
 statusCode: 301,
 headers: a!httpHeader(
 "Location",
 rule!LinkToLaunchForm(----------This is the POST API
 )
 )
 )
 )
)

Stefan Helzle · Answer

I am not sure I fully understand what you are trying to achieve, but find some examples in the documentation here: docs.appian.com/.../Designing_Web_APIs.html