JSON and HTTP for Network APIs

In the previous lesson, you learned to read Python data structures by hand.
Now you need a library to fetch them from a router. The most common one is requests.

It handles opening the HTTPS connection, sending the request, and returning the response:

import requests

response = requests.get("https://192.168.1.1/restconf/data/...")

The data inside that response arrives in JSON.
Two specific details in this section trip up candidates on the exam.

JSON vs Python Dict

When Python talks to a Cisco device, both sides exchange data as JSON text.
JSON looks almost identical to a Python dictionary, with three key differences:

{
    "hostname": "R1",
    "port": 830,
    "enabled": true,
    "interfaces": ["Gi0/0", "Gi0/1"]
}

Table 1 – JSON vs Python syntax

If an exam snippet uses single quotes or capitalized True inside JSON, it is invalid syntax.

Response Parsing

When your script receives JSON from a device, the data arrives as a plain text string. You cannot index a string by key, so you convert it into a Python dict first:

import requests

response = requests.get(url)

print(type(response.text))
print(type(response.json()))

Output:

<class 'str'>
<class 'dict'>

• response.text: Returns raw JSON string. Indexing with key names like response.text["hostname"] crashes.

• response.json(): Parses the JSON string and returns a Python dictionary you can index normally.

Table 2 – Working with JSON in your script