steem forever (rewarding old posts) with beem

What to do when you want to reward an old post with an upvote? There are services that are doing this as steem-forever but they charge some percentage for their service.

We need a script that creates a comment under the post, set the beneficiaries and upvote the comment.
We are using beem:

pip install beem

for this. Store the following script as steem-forever.py

#!/usr/bin/python
from beem import Steem
from beem.comment import Comment
from datetime import datetime, timedelta
import time
import getpass
import argparse


def valid_age(post, hours=156):
    """
    Checks if post is within last twelve hours before payout.
    """
    if post.time_elapsed() > timedelta(hours=hours):
        return False
    return True


if __name__ == "__main__":
    parser = argparse.ArgumentParser()
    parser.add_argument("authorperm")
    parser.add_argument("votepercentage")
    args = parser.parse_args()
    authorperm = args.authorperm
    votepercentage = float(args.votepercentage)
    
    wif = getpass.getpass(prompt='Enter your posting key.')
    stm = Steem(keys=[wif])
    account = stm.wallet.getAccountFromPrivateKey(wif)

    c = Comment(authorperm, steem_instance=stm)
    if c.is_pending() and valid_age(c):
        while c.time_elapsed() < timedelta(seconds = 60 * 15):
            print("waiting that the post is 15 minute old")
            time.sleep(60)        
        c.upvote(weight=votepercentage, voter=account)
    else:
        body = "The reward of this comment goes 100 %% to the author %s. This is done by setting the beneficiaries of this comment to 100 %%." % (c["author"])
        beneficiaries = [{"account": c["author"], "weight": 10000}]
        stm.post("rewarding %s" % c["author"], body, author=account, reply_identifier=c["authorperm"], beneficiaries=beneficiaries)
        c.refresh()
        c_comment = None
        created = None
        for r in c.get_all_replies():
            if r["author"] == account:
                if created is None:
                    created = r["created"]
                    c_comment = r
                elif created < r["created"]:
                    created = r["created"]
                    c_comment = r
        while c_comment.time_elapsed() < timedelta(seconds = 60 * 15):
            print("waiting that the comment is 15 minute old")
            time.sleep(60)
        c_comment.upvote(weight=votepercentage, voter=account)
        print("Comment upvoted")

When running this script, it asks for the posting key. This key is only temporarly stored in the steem object and will be forgotten when the program exits.

Rewarding a paid out post

I selected an old post from fullnodeupdate and will reward it with my test account @beembot with a 50% upvote:

python steem-foreever.py https://steemit.com/full-nodes/@fullnodeupdate/full-api-node-update---25102018 50

A new comment is created and after 15 minutes in a loop the comment is upvoted with 50 %.

The beneficiaries are set to 100 % for giving the complete comment reward to the author.