Slackweb Incoming Webhook Client

1.0.5 · active · verified Thu Apr 16

Slackweb is a minimalistic Python library for sending messages to Slack via incoming webhooks. It provides a simple interface to construct and send webhook payloads, supporting basic text, attachments, and Block Kit components. The current version is 1.0.5, with releases occurring infrequently, primarily for bug fixes or minor enhancements.

Common errors

```
AttributeError: 'Slack' object has no attribute 'chat_postMessage'
```
cause Attempting to use full Slack Web API methods (like `chat_postMessage`) with the `slackweb` library, which is designed only for incoming webhooks.

fix Use the `slack_sdk` library for full Slack Web API access. If you only need webhooks, use `slack.notify()`.
```
requests.exceptions.MissingSchema: Invalid URL 'YOUR_WEBHOOK_URL': No schema supplied. Perhaps you meant https://YOUR_WEBHOOK_URL?
```
cause The webhook URL provided to `slackweb.Slack` is missing the `http://` or `https://` scheme.

fix Ensure your Slack webhook URL starts with `https://hooks.slack.com/...`.
```
TypeError: __init__() missing 1 required positional argument: 'url'
```
cause You tried to instantiate `slackweb.Slack()` without providing the `url` parameter in versions 1.0.3 and later.

fix Pass the webhook URL directly to the constructor: `slack = slackweb.Slack(url='YOUR_WEBHOOK_URL')`.

Warnings

gotcha This library is *only* for Slack Incoming Webhooks. It does not support the full Slack Web API (e.g., chat.postMessage, users.list, RTM API) or Bot Token authentication. For full API access, use `slack_sdk` (the official Python Slack SDK).
Fix: If you need broader Slack API functionality, switch to the `slack_sdk` library. `pip install slack_sdk`.
deprecated Prior to v1.0.3, the `Slack` object could potentially be instantiated without a `url` parameter and set later. As of v1.0.3, it is strongly recommended (and effectively required for immediate use) to pass the webhook URL directly to the constructor.
Fix: Always initialize `slackweb.Slack` by passing the webhook URL: `slack = slackweb.Slack(url='YOUR_WEBHOOK_URL')`.
gotcha The library might not immediately support the newest Slack Block Kit features or advanced authentication methods like OAuth token exchange. Always refer to the official Slack API documentation for the latest webhook payload structure.
Fix: For complex Block Kit layouts, construct the `blocks` payload as a Python dictionary according to Slack's API docs and pass it directly to `slack.notify(blocks=...)`.

Install

pip install slackweb Install stable version

Imports

Slack
wrong:
```
from slackweb import Client
```
correct:
```
from slackweb import Slack
```
The main class is `Slack`, not `Client`.

Quickstart

This quickstart demonstrates how to initialize the `Slack` client with your webhook URL and send various types of messages, including simple text, messages with custom sender information, and messages with attachments. Ensure `SLACK_WEBHOOK_URL` is set in your environment.

import os
import slackweb

# Get your Slack Incoming Webhook URL from environment variables
# e.g., SLACK_WEBHOOK_URL='https://hooks.slack.com/services/T.../B.../...'
WEBHOOK_URL = os.environ.get('SLACK_WEBHOOK_URL', 'https://hooks.slack.com/services/T00000000/B00000000/XXXXXXXXXXXXXXXXXXXXXXXX')

if WEBHOOK_URL == 'https://hooks.slack.com/services/T00000000/B00000000/XXXXXXXXXXXXXXXXXXXXXXXX':
    print("WARNING: Please set the SLACK_WEBHOOK_URL environment variable to a valid Slack Incoming Webhook URL.")
    print("Skipping quickstart execution due to missing URL.")
else:
    try:
        slack = slackweb.Slack(url=WEBHOOK_URL)
        
        # Send a simple text message
        slack.notify(text="Hello from slackweb! This is a test message.")
        print("Successfully sent a simple Slack message.")

        # Send a message to a specific channel with a username and emoji icon
        slack.notify(
            channel="#general", 
            username="My Python Bot", 
            icon_emoji=":robot_face:", 
            text="Another message with custom sender info."
        )
        print("Successfully sent a Slack message with custom sender info.")

        # Send a message with an attachment
        slack.notify(
            attachments=[
                {
                    "title": "Example Attachment",
                    "text": "This is an attachment with some extra info.",
                    "color": "#36a64f"
                }
            ]
        )
        print("Successfully sent a Slack message with an attachment.")

    except Exception as e:
        print(f"An error occurred: {e}")
        print("Please ensure your SLACK_WEBHOOK_URL is correct and accessible.")

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