How to Create a Comment in a Task and Attach a File

Scope: task, im

Who can execute the methods: a user with access to the task and its chat

tasks.task.get — any user with access to the task

im.v2.File.upload — a user with access to the task chat

im.v2.File.download — a user with access to the task chat

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Task comments are stored in the task chat. To add a comment with a file, first get the identifier of the task chat, then upload the file to that chat using the im.v2.File.upload method.

The im.v2.File.upload method uploads the file, attaches it to the chat, and sends the message in a single call. You do not need to upload the file to Drive using a separate method.

The scenario consists of two steps.

Get the task chat chatId using the tasks.task.get method
Send a message with a file using the im.v2.File.upload method

As a result, a comment with an attached file will appear in the task chat. The operation is confirmed by the messageId, chatId, dialogId, and file.id fields in the response of the im.v2.File.upload method.

Before You Start

You need the following to run the example:

an inbound webhook with the task and im scopes
the task taskId. You can get it using the tasks.task.list method
the file to attach to the comment
the file name with an extension, for example file.pdf
the file content in Base64 format without the data:*/*;base64, prefix

The webhook executes requests with the permissions of the user who created it. Do not publish the webhook secret in client-side code or repositories. Store it in environment variables.

For server-side JS examples with B24Hook, use Node.js 18, 20, 22, or later. For new projects, use 22 or later. B24JsSDK is an ES module: save the code in a .mjs file or add "type": "module" to package.json.

For b24pysdk examples, use Python 3.9 or later.

1. Get the Task Chat chatId

To send a message with a file to the task chat, you need a dialog identifier in the chat{chatId} format. Get chatId using the tasks.task.get method.

Use the following parameters:

taskId — the task identifier
select — the array of fields to return. Specify ID and CHAT_ID

How to Use Examples in Documentation

Python

PHP

import { B24Hook } from '@bitrix24/b24jssdk'
        
        const $b24 = B24Hook.fromWebhookUrl(process.env.B24_HOOK)
        // B24_HOOK = 'https://your-domain.bitrix24.com/rest/USER_ID/TOKEN/'
        
        const taskResponse = await $b24.actions.v2.call.make({
            method: 'tasks.task.get',
            params: {
                taskId: 3711,
                select: ['ID', 'CHAT_ID']
            },
            requestId: 'task-get-chat'
        })
        
        if (!taskResponse.isSuccess) {
            throw new Error(taskResponse.getErrorMessages().join('; '))
        }
        
        const chatId = taskResponse.getData().result.task.chatId
        const dialogId = `chat${chatId}`

from b24pysdk import BitrixWebhook, Client
        from b24pysdk.errors import BitrixAPIError
        
        token = BitrixWebhook(
            domain="your-domain.bitrix24.com",
            webhook_token="user_id/webhook_key",
        )
        client = Client(token)
        
        try:
            task = client.tasks.task.get(
                bitrix_id=3711,
                select=["ID", "CHAT_ID"],
            ).response.result["task"]
        except BitrixAPIError as error:
            print(f"Error retrieving the task: {error}")
            raise
        
        chat_id = task["chatId"]
        dialog_id = f"chat{chat_id}"

require_once 'vendor/autoload.php';
        
        use Bitrix24\SDK\Services\ServiceBuilderFactory;
        use Bitrix24\SDK\Core\Exceptions\BaseException;
        use Symfony\Component\EventDispatcher\EventDispatcher;
        
        $serviceBuilder = (new ServiceBuilderFactory(new EventDispatcher(), $log))
            ->initFromWebhook(getenv('B24_HOOK'));
        
        try {
            $task = $serviceBuilder->core->call(
                'tasks.task.get',
                [
                    'taskId' => 3711,
                    'select' => ['ID', 'CHAT_ID']
                ]
            )->getResponseData()->getResult()['task'];
        } catch (BaseException $e) {
            echo 'Error retrieving the task: ' . $e->getMessage();
            return;
        }
        
        $chatId = $task['chatId'];
        $dialogId = 'chat' . $chatId;

As a result, you get the task chat chatId. Convert the value 861 into dialogId: chat861.

{
            "result": {
                "task": {
                    "id": "3711",
                    "chatId": 861
                }
            }
        }

2. Send a Comment with a File

To send a file to the task chat, use the im.v2.File.upload method.

Use the following parameters:

dialogId — the dialog identifier in the chat{chatId} format. For the example from the previous step, this is chat861
fields.name — the file name with an extension
fields.content — the file content in Base64 format
fields.message — the comment text

Python

PHP

const uploadResponse = await $b24.actions.v2.call.make({
            method: 'im.v2.File.upload',
            params: {
                dialogId,
                fields: {
                    name: 'file.pdf',
                    content: 'SGVsbG8gV29ybGQh',
                    message: 'Comment with a file'
                }
            },
            requestId: 'file-upload-to-task-chat'
        })
        
        if (!uploadResponse.isSuccess) {
            throw new Error(uploadResponse.getErrorMessages().join('; '))
        }
        
        const result = uploadResponse.getData().result
        console.log(result.messageId, result.file.id)
        
        $b24.destroy()

import base64
        from pathlib import Path
        
        file_content = base64.b64encode(Path("file.pdf").read_bytes()).decode()
        
        try {
            result = token.call_method(
                "im.v2.File.upload",
                {
                    "dialogId": dialog_id,
                    "fields": {
                        "name": "file.pdf",
                        "content": file_content,
                        "message": "Comment with a file",
                    },
                },
            )["result"]
        except BitrixAPIError as error:
            print(f"Error sending the comment with a file: {error}")
            raise
        
        print(result["messageId"], result["file"]["id"])

try {
            $response = $serviceBuilder->core->call(
                'im.v2.File.upload',
                [
                    'dialogId' => $dialogId,
                    'fields' => [
                        'name' => 'file.pdf',
                        'content' => base64_encode(file_get_contents('/path/to/file.pdf')),
                        'message' => 'Comment with a file',
                    ],
                ]
            );
        } catch (BaseException $e) {
            echo 'Error sending the comment with a file: ' . $e->getMessage();
            return;
        }
        
        $result = $response->getResponseData()->getResult();
        echo 'Comment created, MESSAGE_ID: ' . $result['messageId'];

The method returns the message identifier messageId, the chat identifier chatId, the dialog identifier dialogId, and file data in the file object.

{
            "result": {
                "file": {
                    "id": 9817,
                    "chatId": 861,
                    "type": "file",
                    "name": "file.pdf",
                    "extension": "pdf",
                    "size": 35341,
                    "status": "done",
                    "progress": 100,
                    "authorId": 1
                },
                "messageId": 38655,
                "chatId": 861,
                "dialogId": "chat861"
            }
        }

Check the Result

Open the task with id 3711 and go to the comments. The task chat must contain a message Comment with a file with the attached file file.pdf.

Through REST, verify that the task is linked to the same chat where the file was sent and that the file is available for download.

Python

PHP

const checkResponse = await $b24.actions.v2.call.make({
            method: 'tasks.task.get',
            params: {
                taskId: 3711,
                select: ['ID', 'CHAT_ID']
            },
            requestId: 'task-get-check'
        })
        
        if (!checkResponse.isSuccess) {
            throw new Error(checkResponse.getErrorMessages().join('; '))
        }
        
        const task = checkResponse.getData().result.task
        console.log(task.chatId)
        
        const fileResponse = await $b24.actions.v2.call.make({
            method: 'im.v2.File.download',
            params: {
                dialogId: result.dialogId,
                fileId: result.file.id
            },
            requestId: 'file-download-check'
        })
        
        if (!fileResponse.isSuccess) {
            throw new Error(fileResponse.getErrorMessages().join('; '))
        }
        
        console.log(fileResponse.getData().result)

task = client.tasks.task.get(
            bitrix_id=3711,
            select=["ID", "CHAT_ID"],
        ).response.result["task"]
        
        print(task["chatId"])
        
        file = token.call_method(
            "im.v2.File.download",
            {
                "dialogId": result["dialogId"],
                "fileId": result["file"]["id"],
            },
        )["result"]
        
        print(file)

$task = $serviceBuilder->core->call(
            'tasks.task.get',
            [
                'taskId' => 3711,
                'select' => ['ID', 'CHAT_ID']
            ]
        )->getResponseData()->getResult()['task'];
        
        echo 'CHAT_ID: ' . $task['chatId'];
        
        $file = $serviceBuilder->core->call(
            'im.v2.File.download',
            [
                'dialogId' => $result['dialogId'],
                'fileId' => $result['file']['id'],
            ]
        )->getResponseData()->getResult();
        
        print_r($file);

The scenario is successful if the task chatId matches the result.chatId value returned by im.v2.File.upload, and the upload response contains the following fields:

result.messageId — the identifier of the message in the task chat
result.dialogId — the identifier of the task dialog
result.file.id — the identifier of the file in Drive
result.file.status — the file upload status. The done value means the file was uploaded successfully
the response of im.v2.File.download contains a file download link in the result.downloadUrl field

Errors and Diagnostics

If the method returns an error, check the request data.

Error	Cause and solution
`FILE_EMPTY`	The file name or file content was not passed. Check `fields.name` and `fields.content`
`FILE_INVALID_CONTENT`	`fields.content` contains an invalid Base64 string or a string with the `data:/;base64,` prefix
`FILE_TOO_LARGE`	The file is larger than 100 MB. Reduce the file size or use a different data transfer approach
`CHAT_NOT_FOUND`	The chat from `dialogId` was not found. Check that `chatId` was taken from the correct task and passed with the `chat` prefix
`ACCESS_DENIED`	The webhook user does not have access to the task or the task chat

Repeat the scenario from the step that returned the error. If tasks.task.get returned the error, verify taskId and the user's permissions. If im.v2.File.upload returned the error, repeat only the second step.

What to Consider

im.v2.File.upload replaces the outdated chain im.disk.folder.get + upload through Drive + im.disk.file.commit
The file is passed in fields.content as a Base64 string without the data:*/*;base64, prefix
dialogId for a task chat is built from chatId: if chatId is 861, pass chat861
Re-running the example creates a new message with a file in the task chat

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How to transfer a file from a CRM field to a task

How to attach a task to an SPA

How to Create a Comment in a Task and Attach a File

Before You StartBefore You Start

1. Get the Task Chat chatId1. Get the Task Chat chatId

2. Send a Comment with a File2. Send a Comment with a File

Check the ResultCheck the Result

Errors and DiagnosticsErrors and Diagnostics

What to ConsiderWhat to Consider

Continue LearningContinue Learning

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Before You Start

1. Get the Task Chat chatId

2. Send a Comment with a File

Check the Result

Errors and Diagnostics

What to Consider

Continue Learning