Lightsteem 0.0.9 - Introducing event listeners

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Streaming new operations is a general task we need as app developers, bot developers on the STEEM blockchain. Having helpers for streaming new operations was a priority for the Lightsteem, for a while.

With the new version of Lightsteem, streaming and filtering on the new blocks made easy!

Upgrade to the latest version

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(sudo) pip install lightsteem --upgrade

EventListener

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Pull Request:
github.com/emre/lightsteem/pull/21

EventListener lives on the lightsteem.helpers.event_listener namespace. It has a couple of params you may pass.

• client (Lightsteem client instance.)
• start_block (block number to start streaming. Optional.)
• end_block (block number to stop streaming. Optional)

Examples:

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Stream blockchain for the incoming transfers related to a specific account

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from lightsteem.helpers.event_listener import EventListener
from lightsteem.client import Client

client = Client()
events = EventListener(client)

for transfer in events.on('transfer', filter_by={"to": "emrebeyler"}):
    print(transfer)

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Stream incoming witness vote actions

events = EventListener(client)

for witness_vote in events.on('account_witness_vote', filter_by={"witness": "emrebeyler"}):
    print(witness_vote)

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Stream new comments and posts including utopian-io as a tag

from lightsteem.client import Client
from lightsteem.helpers.event_listener import EventListener

import json

c = Client()
events = EventListener(c)

def filter_tags(comment_body):
    if not comment_body.get("json_metadata"):
        return False

    try:
        tags = json.loads(comment_body["json_metadata"])["tags"]
    except KeyError:
        return False
    return "utopian-io" in tags


for op in events.on("comment", condition=filter_tags):
    print(op)

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It's possible and easy to filter every kind of action in the blockchain. If you don't pass start_block or end_block, then the current last irreversible block will be used to start with and listener will stream to the forever.

0.0.8 - Adding Shortcuts for Follow, Unfollow, Ignore, Unignore

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Pull Request: github.com/emre/lightsteem/pull/20

With this version, Account helper also gained new methods for Relationship actions.

• account.follow("username")
• account.unfollow("username")
• account.ignore("username")
• account.unignore("username")

shortcuts added for the convenience. Building custom jsons for these operations were overkill, before.

Notes and the Roadmap

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I am switching my old Steem-Python bots/scripts to Lightsteem with the new version. There will be more updates to EventListener, most likely. (API will stay the same but I have a feeling there will be more exception handling and retry mechanisms.)

I don't post micro updates to the blog, so it's better to watch the repo at Github.

Contributing

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• You can stop by Lightsteem discord and join the development with your feedback and ideas.

• You can pick an open issue and start working on it. But we should reach a consensus about the design decisions before any merge.

• Make sure you update the documentation and unit tests for each change you do on the codebase.