Parse JSON from a multi-part http response? (In postman)

Question

I'm calling a web api that returns a multi part HTTP response.

In the form of

...possible other content...

--97b6f48d-7f7e-4e96-bd0b-ced047222460
Content-Type: application/json; charset=utf-8

{"key":"this is the JSON"}
--97b6f48d-7f7e-4e96-bd0b-ced047222460--

...possible other content...

I want just the JSON: {"key":"this is the JSON"}.

The GUID 97b6f48d-7f7e-4e96-bd0b-ced047222460 is a boundary identifier, identifying that part of the http response, randomly generated.

I know that there is only one part of the response that has JSON content. What is the best way for me to extract it?

FYI I'm using scripting in postman, so it will need to be javascript.

Answer 1

I haven't found any automatic way to split the multi part HTTP response in postman so I've resorted to parsing the entire response and finding the {...} JSON

Since I know for a certainty that there is only one JSON document object inside of the entire multi-part response, I can look for the outer-most brackets.

It utilizes a counter variable to keep track of the opening/closing brackets. When the counter hits zero (after finding an opening bracket, which sets the counter to 1), we know that we have found the end of the JSON.

This is the code:

//find the JSON in the multi part response
var p, q;
var foundFirstBracket = false;
var stackCount = 0;
for(var i = 0; i < responseBody.length; i++)
{
    if(responseBody[i] === '{')
    {
        if(!foundFirstBracket) 
        {
            foundFirstBracket = true;
            p = i;
        }
        stackCount++;
    }
    else if(responseBody[i] === '}') 
    {
        stackCount--;
    }
    if(stackCount === 0 && foundFirstBracket)
    {
        q = i;
        break;
    }
}
var jsonString = responseBody.substring(p, q+1);
var jsonData = JSON.parse(jsonString);