Error Paring JSON response -- JSONError: Unexpected token u

New to APIs/Postman
,
1

I’m developing a pre-request script. This script does a POST to get a JWT that I’ll use for my main request. The POST returns with a http 200 so all good… if I comment out the attempted parse, it all completes with no issue. I have a result that passes JSONlint … so I didn’t expect any issues.

image_2
image_21798×327 177 KB
image_3
image_31082×771 49.9 KB
inage_1
inage_11798×1314 211 KB

Its a simple response and I simply want to get the “val” attribute but the JSONParse fails.
The Postman console says “JSONError: Unexpected token u in JSON at position 0” and as you can see there’s no “u” attribute in the response. Yes, I see that inside the value for “val” the letter ‘u’ turns up… that can’t be the issue.

How can I sort out what’s happening so I can make this work?

{
“tt”: “JWT”,
“val”: “eyJraWQiOiJJYW1Kd2tLZXkiLCJhbGciOiJFUzI1NiJ9.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.EuD6sBbUfFYSuJ7EgZdz7s5j4bksLl9nlfu1-i0mZSnREnXf_GWTCiu0FA34AZnSKzTjW_Lu82lRnx6taoQ6Vw”,
“v”: “1.0”,
“exp”: 1612395550
}

2

I think I see what’s happening here… but I don’t know what to do about it. If I manually create a request that’s a POST as above (same content as in my pre-request script) I get a response body… I can see it in the UI (same as above) … but if I make a POST in the pre-request script I don’t have a body… I have status and status-code and the response headers, stream… but there’s no body like I would have if I made a GET.

I can’t use GET, I have to use POST (its not my interface) …

Is there anything I can do?

3

Can you try to do log of response before parsing to JSON.
console.log(response.body);
And check how data is coming in response.
If there is no data for it try to do console.log(response);
Then we can try to extract the data

4

May be this blog can help you :slight_smile:

1 Like
5

You don’t need to parse that response like that, it’s not the same as the main response.

You would just need to use this in the sendRequest() function:

pm.environment.set('jwt-token', response.json().val)
1 Like
6

Thanks, I tried that even before posting - console.info( response.body );
I get “undefined” in the logs… which is why I’m seeing the “u” parse error that complains about an unexpected token “u” …

I DO have a response object.

{id: “344e2763-ca69-46e4-a10c-f8527b5bc2d9”, status: “OK”, code: 200…}

  1. id: “344e2763-ca69-46e4-a10c-f8527b5bc2d9”
  2. status: “OK”
  3. code: 200
  4. :arrow_forward:header: [5]
  5. :arrow_forward:stream: {…}
  6. cookie: [0]
  7. responseTime: 3960
  8. responseSize: 2229
7

BINGO, I think I’m getting some where …

8

Thanks, I’ll review and maybe there’s another trick in there for me to learn.