PHP+Slack: 5 easy ways to send a message

PHP+Slack: 5 easy ways to send a message

# php# slack# symfony

Sunday, August 27, 2023

Slack has become a popular tool for workplace communication, allowing teams to collaborate easily. It can be useful to learn how to send messages to Slack from code. This article shows 5 easy ways to do this using PHP:

Preconditions

Slack API

Slack provides a variety of API endpoints and methods, which can be found in the documentation.

Today we're going to focus on the chat.postMessage endpoint. It sends some text TEXT to the particular channel CHANNEL_NAME by the bot BOT_API_TOKEN

curl --location 'https://slack.com/api/chat.postMessage' \
--header 'Content-Type: application/json; charset=utf-8' \
--header 'Authorization: Bearer BOT_API_TOKEN' \
--data '{
    "channel": "CHANNEL_NAME",
    "text": "TEXT"
}'

There are many ways to call this endpoint and send a message to the channel within a PHP project. We will cover 4 of them.

HTTP request with cURL

<?php

$botApiToken = 'xoxb-your-bot-api-token';
$channelName = 'your channel name';
$text = 'Hello, I am from PHP!';

$url = "https://slack.com/api/chat.postMessage";

$curl = curl_init();
curl_setopt_array($curl, [
    CURLOPT_URL => $url,
    CURLOPT_RETURNTRANSFER => true,
    CURLOPT_CUSTOMREQUEST => 'POST',
    CURLOPT_POSTFIELDS => json_encode([
        "channel" => $channelName,
        "text" => $text,
    ]),
    CURLOPT_HTTPHEADER => [
        "Authorization: Bearer {$botApiToken}",
        'Content-Type: application/json; charset=utf-8',
    ],
]);
curl_exec($curl);
curl_close($curl);

Symfony HTTP client

Symfony is one of the most popular PHP frameworks. It provides a lot of different components out of the box and one of them is HTTP Client. It allows you to make HTTP requests easily.

Installation

composer require symfony/http-client

Standalone

<?php

require 'vendor/autoload.php';

use Symfony\Component\HttpClient\HttpClient;

$botApiToken = 'xoxb-your-bot-api-token';
$channelName = 'your channel name';
$text = 'Hello, I am from Symfony HTTP Client!';

$client = HttpClient::create([
    'base_uri' => 'https://slack.com',
]);

$client->request('POST', "/api/chat.postMessage", [
    'headers' => [
        'Accept' => 'application/json; charset=utf-8',
    ],
    'auth_bearer' => $botApiToken,
    'json' => [
        'channel' => $channelName,
        'text' => $text,
    ],
]);

Inside Symfony app

Prepare a scoped client in config/packages/framework.yaml:

parameters:
    env(SLACK_BOT_API_TOKEN): 'xoxb-your-bot-api-token'

framework:
    http_client:
        scoped_clients:
            slack.client:
                base_uri: 'https://slack.com'
                auth_bearer: '%env(SLACK_BOT_API_TOKEN)%'
                headers:
                    Accept: 'application/json; charset=utf-8'

And use it inside your service:

<?php

namespace App;

use Symfony\Contracts\HttpClient\HttpClientInterface;

class YourService
{
    public function __construct(
        private readonly HttpClientInterface $slackClient,
    )
    {
    }

    public function sendMessage(string $text): void
    {
        $channelName = 'your channel name';

        $this->slackClient->request('POST', '/api/chat.postMessage', [
            'json' => [
                'channel' => $channelName,
                'text' => $text,
            ],
        ]);
    }
}

Symfony Slack Notifier

Another Symfony component that can send a message to the Slack channel is Slack Notifier.

Installation

composer require symfony/slack-notifier

Standalone

<?php

require 'vendor/autoload.php';

use Symfony\Component\Notifier\Bridge\Slack\SlackTransport;
use Symfony\Component\Notifier\Chatter;
use Symfony\Component\Notifier\Message\ChatMessage;


$botApiToken = 'xoxb-your-bot-api-token';
$channelName = 'your channel name';
$text = 'Hello, I am from Symfony Slack Notifier!';

$slackTransport = new SlackTransport($botApiToken, $channelName);
$chatter = new Chatter($slackTransport);
$chatMessage = new ChatMessage($text);
$chatter->send($chatMessage);

Inside Symfony app

Configure a notifier chatter transport in config/packages/framework.yaml:

parameters:
    env(SLACK_DSN): 'slack://BOT_API_TOKEN@default?channel=CHANNEL_NAME'

framework:
    notifier:
        chatter_transports:
            slack: '%env(SLACK_DSN)%'

And use it inside your service:

<?php

namespace App;

use Symfony\Component\Notifier\ChatterInterface;
use Symfony\Component\Notifier\Message\ChatMessage;

class YourService
{
    public function __construct(
        private readonly ChatterInterface $slackChatter
    )
    {
    }

    public function sendMessage(string $text): void
    {
        $this->slackChatter->send(new ChatMessage($text));
    }
}

jolicode PHP client for Slack API

There are other framework-independent libraries that can help you send a message to the Slack channel. Slack calls them Community Tools.

One of them is jolicode's PHP client for Slack's API

Installation

composer require jolicode/slack-php-api

Standalone

<?php

require 'vendor/autoload.php';

use JoliCode\Slack\Api\Client;
use JoliCode\Slack\ClientFactory;

$botApiToken = 'xoxb-your-bot-api-token';
$channelName = 'your channel name';
$text = 'Hello, I am from Jolicode Client!';

$client = ClientFactory::create($botApiToken);

$client->chatPostMessage([
    'channel' => $channelName,
    'text' => $text,
]);

Slack Webhook

Another way to send a message to a channel is Slack Webhook.

You can create your webhook here

After webhook is created, copy YOUR_WEBHOOK_URL and make a simple cURL request. It will send TEXT to your CHANNEL_NAME.

curl --location 'YOUR_WEBHOOK_URL' \
--header 'Content-Type: application/json' \
--data '{
    "channel": "CHANNEL_NAME",
    "text": "TEXT"
}'

In PHP it will look like this

<?php

$text = 'Hello, I am from PHP Slack Webhook!';
$channelName = 'your channel name';
$url = "YOUR_WEBHOOK_URL";

$curl = curl_init();
curl_setopt_array($curl, [
    CURLOPT_URL => $url,
    CURLOPT_RETURNTRANSFER => true,
    CURLOPT_CUSTOMREQUEST => 'POST',
    CURLOPT_POSTFIELDS => json_encode([
        "channel" => $channelName,
        "text" => $text,
    ]),
    CURLOPT_HTTPHEADER => [
        'Content-Type: application/json; charset=utf-8',
    ],
]);
curl_exec($curl);
curl_close($curl);

Summary

There are many ways to send a message to a Slack channel. This can be done using a Slack App or a Slack Webhook. The choice you make depends on your needs and the technologies you're working with. This article shows 5 easy ways to send messages to Slack using PHP, it's up to you which one to use.