Implementing Follow

Published on: 2024-07-19 13:49:43 +1000 AEST

Pre-requisite: Signing Algorithm , Webfinger

It’s a requirements for you to setup your webfinger and actor object prior to implementing this features. You would also need to implement the following Signing Algorithm (for simplicity, we’ll implement it in Python). After implemented both the webfinger and key signing algorithm, you can use the below example to send a follow request to someone on ActivityPub instances.

Example - a simple python program used to followed

# Assuming the above algorithm is stored under KeySigningHandler.py
# under the same directory
import requests
from KeySigningHandler import *


# This is the url that leads to your actor object
actorId = "https://noah.netlify.app/noah/actor.json"

# This is the file path leading to the private key generated 
# using the algorithm found in "Webfinger for Discovery Post"
privateKeyPath = "..."

# This is the webfinger of the user that you want to follow
webfinger = "@alice@mastodon.social"

handler = KeySigningHandler(actorId, privateKeyPath)
activity = handler.generateFollowActivity(webfinger)
inboxUrl, body, headers = handler.generateSignedHeaders(activity, webfinger)

response = requests.post(inboxUrl, headers=headers, data=data)
if response.ok:
	print(f"Successfully followed: {webfinger}")
else:
	print(f"{response.status_code}: Unable to follow {webfinger}")
	print(response.reason)

Quick Summary of the Above Code:

Things you need:

  1. URL that leads to your actor Object
  2. The person you want to follow Webfinger

Process:

  1. Initialise the KeySigningHandler object, using the actor object url and path to your private key
  2. Generate the @Follow activity using the target user webfinger
  3. Calls the generateSignedHeader method using the previously generated activity and target user webfinger. This would return the (inboxUrl, body, headers). Each of the components can be explained as followed: 3.1. inboxUrl - the url that we needs to send the returned body and header to 3.2. body - the json version of the activity that was previously generated in step 2 3.3. headers - formatted headers with necessarily information to meet the ActivityPub protocol requirements
  4. Using the returned values from step 3, we make a POST HTTP request to inboxUrl using the body and headers

The structure of a @Follow activity is as followed:

{
	"@context": "https://www.w3.org/ns/activitystreams",
	"type": "Follow",
	"actor": "{YOUR_ACTOR_OBJECT_URL}", 
	"object": "{TARGET_ACTOR_OBJECT_URL}"
}

References

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