Use a list environment variable within pre-request scriipt

Ask the Experts and Postman Tips
1

Would anyone know how to import a list (of IPv4 addresses in this instance) into a postman Pre-request script? So for example - I have a request that is working, but uses a ‘hard-coded’ list of IPs in the Pre-request script - what I’m after idsa way to import this list somehow, maybe an environment variable or an imported list:

var deployments = [];
// Iterate over the range for i (1-4) number of nodes
var nodeIP= ["10.0.1.1","10.0.1.2","10.0.1.3","10.0.2.1","10.0.2.2" ]
for (var x = 0; x < nodeIP.length; x++) {
    // Iterate over the range for i (1-30) for the number of deployment
                ;
        // Create deployment object
        var deployment = {
            "template-name": "SRL_ACL_System_Filter",
            "target-data": JSON.stringify(pstmtsrlpayload),
            "targets": [
                {
                    "target": "/nsp-equipment:network/network-element[ne-id='"+nodeIP[x]+"']",
                    "target-identifier-value": "system-filter"
                }
            ],
            "deployment-action": "deploy",
            "merge": false
        };

I have tried things like the following without success:

var nodeIP = pm.environment.get("pdiSrlList1");

where the environment variable is:

pdiSrlList1 = "10.0.1.1","10.0.1.2","10.0.1.3","10.0.2.1","10.0.2.2"
2

HI @daiwattnokia. Welcome to the Postman Community :postman_logo:

What will be the data source of the list of IPs? Are you looking to get them from an API, have them in a csv or JSON file, etc? It’ll be helpful to know how this data will be presented to suggest a good way of programmatically “importing” it.

3

Thanks @gbadebo-bello,
I don’t mind how they are presentecd - CSV, JSON, postman environment variable or something else - that is easy to adapt. So let’s say CSV - that’s the simplest - I have to present this as an easy method to a field community, who won’t want any excessive complexity

4

Hi @daiwattnokia.

What errors did you get when you used an environment variable? Can you share maybe a sample code of how you’re using this with an environment variable. Ideally, that should work for your usecase.

5

You need to store the variable as an array, and then JSON parse it otherwise it will be treated as a string.

image

var nodeIP =JSON.parse(pm.environment.get("nodeIP"));

for (var x = 0; x < nodeIP.length; x++) {
    console.log(nodeIP[x]);
}

image

6

If you want to use the collection runner and JSON as the input file, then the JSON file should look like the following.

[
    {
        "nodeIP": [
            "10.0.1.1",
            "10.0.1.2",
            "10.0.1.3",
            "10.0.2.1",
            "10.0.2.2"
        ]
    }
]

You don’t need to parse the JSON using this method.

var nodeIP = pm.iterationData.get("nodeIP");

for (var x = 0; x < nodeIP.length; x++) {
    console.log(nodeIP[x]);
}
7

Thanks will try those suggestion today and get back to you

8

Thanks Mike, that worked perfectly :grinning:

9

Did you really mark your own post as the solution? Mmmm.

10

Sorry, my mistake, I’ll correct that

11

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