POST a JSON payload to a Slack Incoming Webhook using Python requests

slack_webhook_post.py

'''
This is an example of how to send data to Slack webhooks in Python with the
requests module.
Detailed documentation of Slack Incoming Webhooks:
https://api.slack.com/incoming-webhooks

'''

import json
import requests

# Set the webhook_url to the one provided by Slack when you create the webhook at https://my.slack.com/services/new/incoming-webhook/
webhook_url = 'https://hooks.slack.com/services/T00000000/B00000000/XXXXXXXXXXXXXXXXXXXXXXXX'
slack_data = {'text': "Sup! We're hacking shit together @HackSussex :spaghetti:"}

response = requests.post(
    webhook_url, data=json.dumps(slack_data),
    headers={'Content-Type': 'application/json'}
)
if response.status_code != 200:
    raise ValueError(
        'Request to slack returned an error %s, the response is:\n%s'
        % (response.status_code, response.text)
    )

Okay, so you're trying to post the Farmhouse Thai Cuisine example to Slack via Webhook from the api.slack.com Block Kit Builder.

I've done something similar here. In that example, I use OATH as I also wanted to upload an image but have a variable which can be set to use webhooks instead. The Block Kit is built on the fly by the script.

Why not try something simpler like this:

data = []
data.append({"type": "section","text": {"type": "mrkdwn","text": "I'm posting to Slack via webhook"}})

def post_to_slack(message):
    webhook_url = 'https://hooks.slack.com/services/MY/WEBHOOK/URL'
    slack_data = json.dumps({'blocks': message})
    response = requests.post(
        webhook_url, data=slack_data,
        headers={'Content-Type': 'application/json'}
    )
    if response.status_code != 200:
        raise ValueError(
            'Request to slack returned an error %s, the response is:\n%s'
            % (response.status_code, response.text)
        )

post_to_slack(data)

Then you can build up your Block Kit as you wish.

@guymorrell Using this approach, I get a notification that the sent content can't be displayed. If I open the Slack Channel, the provided text is shown without any formatting.

@johannesber and @NandanSatheesh try putting the content directly into a separate json file then loading it into a variable as follows:

import slack
import json
import requests

with open("block.json", "rt") as block_f:
    data = json.load(block_f)

def post_to_slack(message):
    webhook_url = 'https://hooks.slack.com/services/MY/WEBHOOK/URL'
    slack_data = json.dumps({'blocks': message})
    response = requests.post(
        webhook_url, data=slack_data,
        headers={'Content-Type': 'application/json'}
    )
    if response.status_code != 200:
        raise ValueError(
            'Request to slack returned an error %s, the response is:\n%s'
            % (response.status_code, response.text)
        )

post_to_slack(data)

I've put this up here: https://github.com/guymorrell/slack-webhooks-blockkit

@guymorrell now this works like a charm! Thanks for your help!

Hi, is there away you can use the same method but posting in a thread instead of the channel on Slack?

Yup. See https://api.slack.com/messaging/webhooks and https://api.slack.com/messaging/sending#threading

Hi @guymorrell I am trying to publish cucumber report (Cucumber.json) from Jenkins to slack using slak-notifier-plugin but I got the below error
java.lang.RuntimeException: Received HTTP Status code [400] while posting to slack
at org.jenkinsci.plugins.slacknotifier.SlackClient.postToSlack(SlackClient.java:62)
at org.jenkinsci.plugins.slacknotifier.SlackClient.postToSlack(SlackClient.java:54)
at org.jenkinsci.plugins.slacknotifier.SlackClient.postToSlack(SlackClient.java:41)
at org.jenkinsci.plugins.slacknotifier.CucumberSlackService.sendCucumberReportToSlack(CucumberSlackService.java:33)
at org.jenkinsci.plugins.slacknotifier.CucumberSlackPostBuildNotifier.perform(CucumberSlackPostBuildNotifier.java:67)
at hudson.tasks.BuildStepMonitor$2.perform(BuildStepMonitor.java:32)
at hudson.model.AbstractBuild$AbstractBuildExecution.perform(AbstractBuild.java:741)
at hudson.model.AbstractBuild$AbstractBuildExecution.performAllBuildSteps(AbstractBuild.java:690)
at hudson.model.Build$BuildExecution.post2(Build.java:186)
at hudson.model.AbstractBuild$AbstractBuildExecution.post(AbstractBuild.java:635)
at hudson.model.Run.execute(Run.java:1878)
at hudson.model.FreeStyleBuild.run(FreeStyleBuild.java:43)
at hudson.model.ResourceController.execute(ResourceController.java:97)
at hudson.model.Executor.run(Executor.java:428)
Build step 'Send Cucumber Report to Slack' marked build as failure

I could not be able to send the json which is made with Block Kit too. Can you please help me here?

Hi @Udhay1316, can you post trivial messages to slack? See https://github.com/guymorrell/slack-post-oath

Digging the history up but this seems to not work as intended anymore.
What I get as a result is no_text when I try to post a message. If I add the text field, it ignores the blocks.
Have you seen this issue before?

Hi @guymorrell
A simple text worked fine , but I'm trying to send this payload :
{
"Title": "Resources in AWS ~> eng-sbx",
"icon_emoji": ":money:",
"Resource_Count": {
"CloudFormationStack": "259",
"CloudWatchLog Group": "4319",
"DynamoDBTable": "119",
"EC2Address": "7",
"EC2Instance": "34",
"EC2Security Group": "877",
"GlueDatabase": "14",
"LambdaFunction": "831",
"ECRRepository": "117",
"ECRImage": "6602",
"ELBLoad Balancer": "34",
"EMRCluster": "1",
"ElastiCacheCluster": "20",
"ElastiCacheReplication Group": "5",
"GlueCrawler": "10",
"KinesisStream": "24",
"EFSFile System": "9",
"EKSNode Group": "13",
"EKSCluster": "5",
"SageMakerApp": "7",
"SageMakerNotebook Instance": "2",
"RedshiftSnapshot": "2",
"RDSInstance": "18",
"RDSSnapshot": "3",
"EC2Snapshot": "40",
"EC2Volume": "224",
"S3Bucket": "123",
"IAMPolicy": "157",
"IAMRole": "359"
}
}

I keep having error 400 . Can you help me please ?

Traceback (most recent call last):
File "testing.py", line 183, in
print(test())
File "testing.py", line 179, in test
response = post_slack(result)
File "testing.py", line 160, in post_slack
raise ValueError(
ValueError: Request to slack returned an error 400, the response is:
missing_text_or_fallback_or_attachments

json={"text": data}

Amazing! Working like a charm!

@rafaelnpaiva - I have this problem also.

You need to use the block strucutre that Slack is expecting: (found here)

{
	"blocks": [
		{
			"type": "section",
			"text": {
				"type": "plain_text",
				"text": "This is a plain text section block.",
				"emoji": true
			}
		}
	]
}

I also need to send a simple JSON payload, and I really don't understand why there isn't a way to send our own key:value JSON block...I get that it won't nessasarily be pretty like Slack likes things to be... but sometimes we just need payloads.

@guymorrell do you have any ideas?

Hi, this is working example:

import requests

def send_slack_notif():

    url = 'YOUR_SLACK_WEBHOOK_URL'
    payload = {
        "blocks": [
            {
			    "type": "section",
			    "text": {
				    "type": "plain_text",
				    "text": ":red_circle: This is a plain text section block.",
				    "emoji": True
			    }
	}
        ]
    }
    r = requests.post(url, json=payload)
    
send_slack_notif()

I want to format the code in the form of code.
```
slack_data = {
"text": "```\n" + message + "\n```"
}

    response = requests.post(
        url,
        proxies={
            "http_proxy": <proxy>,
        },
        json=slack_data,
        headers={"Content-Type": "application/json"},
        timeout=5,
    )
    print(response.text)
   ```

This does not format my code.