Making API Calls

Below are some code snippets in Python3 that might assist in making API calls.

An example Python REST client can be found at https://github.com/openl2m/api_client

A very simple example to make an API call could like this:

import requests

headers = {
    "Authorization": "Token <your token>",
    "Content-Type": "application/json",     # we use JSON posting format.
    }
url="your OpenL2M server url"
# a GET api call
endpoint = f"{url}/api/switches/"
response = requests.get(url=endpoint, headers=headers)
# a POST api call
endpoint = f"{url}/api/<group>/<switch_id>/interface/<interface_id>/description/"
response = request.post(url=endpoint, headers=headers, json={ 'description': "your new description here" } )

If the API return is successful (ie. 200), you can find the resulting data in “response.json()”. Parse as needed.

For most POST calls, if successful, the return will include a “result” value that describes the result of the action taken.

If there is an error, the server may return a “reason” entry. You can parse this also with response.json()

if response.status_code ==  requests.codes.ok:
    # parse the return
    my_data = response.json()
    ...
else:
    print(f"Failed with return code {response.status_code}: {response.json().get('reason', 'No reason found!')}")

POSTing data

On the server side, OpenL2M(ie. Django) parses both “application/json” and “application/x-www-form-urlencoded” POST requests. We use the “request.data” dictionary object for this, as explained in https://www.django-rest-framework.org/api-guide/parsers/

This means that your client side script can send POST data with either format. This is shown in the two Python examples below.

Note that the Python ‘requests’ object automatically selects the content encoding based on the parameter given (e.g. data vs. json) So the two examples only differ on that field!

Here is an example with ‘x-www-form-urlencoded’ POST format, to set an interface description.

import requests

headers = {
    "Authorization": f"Token <your token here>",
}
form_data = {
    'description': "<your description>",
}
try:
    response = requests.post(url=<api url>, data=form_data, headers=headers)
except  Exception as err:
    # handle error
# parse response as needed, eg. look for response.status == 200, etc.

This is the equivalent ‘application/json’ POST format:

import requests

headers = {
    "Authorization": f"Token <your token here>",
}
json_data = {
    'description': "<your description>",
}
try:
    response = requests.post(url=<api url>, json=json_data, headers=headers)
except  Exception as err:
    # handle error
# parse response as needed, eg. look for response.status == 200, etc.