Conditional JSON payload based on csv variables

Help Hub
1

Hi everybody,

I’m quite new with POSTMAN so sorry if the question can be a little “neif” but i’ve this problem and i don’t know how to fix it.

Basically i’m using .csv files to collect variables that then will be used by postman POSTs to populate {{…}} items inside the JSON payload.

Depending on the value of csv fields, i can have or not piece of JSON code included in the post.

Just with an example:

Let’s suppose to have the csv done like this one:

VRF_NAME,BD_NAME,BD_NAME_ALIAS,IP_ANYCAST,L3OUT_ASSOCIATION
IRIDEOS_VRF,IRIDEOS_BD1,IRIDEOS_BD1_ALIAS, ,IRIDEOS_L3OUT
IRIDEOS_VRF,IRIDEOS_BD2,IRIDEOS_BD2_ALIAS,10.2.1.1/24,
IRIDEOS_VRF,IRIDEOS_BD3,IRIDEOS_BD3_ALIAS,10.3.1.1/24,IRIDEOS_L3OUT

As you can see, in the 2nd line is missing the value for the “IP_ANYCAST” variable and in the 3rd line is missing the value for the “L3OUT_ASSOCIATION” variable.

Now, the POST call in JSON is like this one:

{
“fvBD”: {
“attributes”: {
“dn”: “uni/tn-{{TENANT_NAME}}/BD-{{BD_NAME}}”,
“mac”: “00:22:BD:F8:19:FF”,
“arpFlood”: “true”,
“name”: “{{BD_NAME}}”,
“nameAlias”: “{{BD_NAME_ALIAS}}”,
“rn”: “BD-{{BD_NAME}}”,
“unicastRoute”: “true”,
“unkMacUcastAct”: “flood”,
“status”: “created”
},
“children”: [
{
“fvSubnet”: {
“attributes”: {
“dn”: “uni/tn-{{TENANT_NAME}}/BD-{{BD_NAME}}/subnet-[{{IP_ANYCAST}}]”,
“ctrl”: “”,
“ip”: “{{IP_ANYCAST}}”,
“rn”: “subnet-[{{IP_ANYCAST}}]”,
“status”: “created”
},
“children”:
}
},
{
“fvRsCtx”: {
“attributes”: {
“tnFvCtxName”: “{{VRF_NAME}}”,
“status”: “created,modified”
},
“children”:
}
},
{
“fvRsBDToOut”: {
“attributes”: {
“tnL3extOutName”: “{{L3OUT_ASSOCIATION}}”,
“status”: “created”
},
“children”:
}
}
]
}
}

Want i wont to get as outcome is:

  1. Not include the portion below for the line where “IP_ANYCAST” is empty (or null)

{
“fvSubnet”: {
“attributes”: {
“dn”: “uni/tn-{{TENANT_NAME}}/BD-{{BD_NAME}}/subnet-[{{IP_ANYCAST}}]”,
“ctrl”: “”,
“ip”: “{{IP_ANYCAST}}”,
“rn”: “subnet-[{{IP_ANYCAST}}]”,
“status”: “created”
},
“children”:
}
}

  1. not include the portion below for the line where “L3OUT_ASSOCIATION” is empty (or null)

{
“fvRsBDToOut”: {
“attributes”: {
“tnL3extOutName”: “{{L3OUT_ASSOCIATION}}”,
“status”: “created”
},
“children”:
}
}

So in summary, i need to make the JSON payload dynamically dependent on some variables. How can i get that?

I really appreciate your feedback.
Thanks
Mario

2

@mrosi Welcome to the community! :wave:

Before we get into solving this issue, just to be sure - you’re using this in collection runner right?

3

Hi Sivcan,
yes i’m using in collection runner!

Thanks for your time

4

@mrosi
Here’s what you can do:

  1. Build a dynamic request body, what I mean by that is you need to build the request body from the pre-request script, and make it a variable something like this:

    image
    image1370×344 23.6 KB

  2. So every iteration in the runner will get the corresponding data from the csv file.
    To access the current iteration data you can use the pm.iterationData API in your pre-request script:

let currentData = pm.iterationData.toJSON(),
 dynamicRequestBody = {};

// Now let's build the body using conditionals etc:
if (currentData.IP_ANYCAST) {
  dynamicRequestBody = currentData;
}
else {
  dynamicRequestBody = { name: currentData.NAME };
}

pm.variables.set('dynamicRequestBody', JSON.stringify(dynamicRequestBody));

This is just an example on how you can dynamically build the request body using the pre-request script with the help of local variables.

Now, based on your conditions you can build this body and store it as a local variable and during the request execution, this variable will get resolved and thus you can make the API call based on your CSV data.

5

many thanks,
i’ll try to reproduce what you are suggesting.