How to Create a Task with an Attached File

Scope: drive, tasks

Who can execute the method: users with access to the drive and tasks sections

If you are developing integrations for Bitrix24 using AI tools (Codex, Claude Code, Cursor), connect the MCP server so that the assistant uses the official REST documentation.

In Bitrix24, there are two types of file fields:

File. This field is not linked to the drive; files are uploaded directly through a Base64 format string.
File (drive). This field is linked to the drive, and it stores the ID of the drive object. The Base64 format is not processed in this field, so the file must first be uploaded to the Bitrix24 drive.

To create a task with a file, we will sequentially execute two methods:

drive.folder.uploadfile — this method uploads a file to the drive.
tasks.task.add — this method creates a task.

1. Uploading a File to the Bitrix24 Drive

To upload a file to the drive, we use the method drive.folder.uploadfile with the following parameters:

id — specify the value 1739 — the identifier of the drive folder where we will upload the file.
data — specify the file name NAME, which will be used to save the file on the Bitrix24 drive.
fileContent — pass the file in the format ['file_name.extension', 'file as a Base64 encoded string'].

Uploading the file to the drive is a necessary step since the UF_TASK_WEBDAV_FILES field in tasks only accepts the IDs of drive files.

How to Use Examples in Documentation

PHP

Python

BX24.callMethod(
            "drive.folder.uploadfile",
            {
                id: 1739,
                data: {
                    NAME: "ava555.jpg"
                },
                fileContent: [
                    'avatar.jpg',
                    '/9j/4AAQSkZJRgABAQEASABIAAD/2wBDAAQDAwQDAwQEAwQ///+dAYq6YFKoAv/AFnAa6ArKv8AAtFJVppxCEAulxQ2DWgfMR//2Q=='
                ]
            }
        );

require_once('crest.php');
        
        $result = CRest::call(
            'drive.folder.uploadfile',
            [
                'id' => 1739,
                'data' => [
                    'NAME' => 'ava555.jpg'
                ],
                'fileContent' => [
                    'avatar.jpg',
                    '/9j/4AAQSkZJRgABAQEASABIAAD/2wBDAAQDAwQDAwQEAwQ///+dAYq6YFKoAv/AFnAa6ArKv8AAtFJVppxCEAulxQ2DWgfMR//2Q=='
                ]
            ]
        );
        
        echo '<PRE>';
        print_r($result);
        echo '</PRE>';

from b24pysdk import BitrixWebhook, Client
        
        client = Client(
            BitrixWebhook(
                domain="your-domain.bitrix24.com",
                auth_token="your-webhook-token",
            )
        )
        
        result = client.disk.folder.uploadfile(
            bitrix_id=1739,
            data={
                "NAME": "ava555.jpg",
            },
            file_content=[
                "avatar.jpg",
                "/9j/4AAQSkZJRgABAQEASABIAAD/2wBDAAQDAwQDAwQEAwQ///+dAYq6YFKoAv/AFnAa6ArKv8AAtFJVppxCEAulxQ2DWgfMR//2Q==",
            ],
        ).response.result

As a result of uploading the file to the drive, we receive two different file ID values:

FILE_ID: 28073 — the internal file ID value.
ID: 6687 — the ID of the drive object; this value is used in methods for working with fields of the "file (drive)" type. If the request to change the "file (drive)" field passes the FILE_ID, the file will either not be attached to the task because there is no drive object with that ID, or the wrong file will be attached.

{
            "result": {
                "ID": 6687,
                "NAME": "ava555.jpg",
                "CODE": null,
                "STORAGE_ID": "1",
                "TYPE": "file",
                "PARENT_ID": "1739",
                "DELETED_TYPE": 0,
                "GLOBAL_CONTENT_VERSION": 1,
                "FILE_ID": 28073,
                "SIZE": "405559",
                "CREATE_TIME": "2024-11-01T17:00:55+02:00",
                "UPDATE_TIME": "2024-11-01T17:00:55+02:00",
                "DELETE_TIME": null,
                "CREATED_BY": "1",
                "UPDATED_BY": "1",
                "DELETED_BY": null,
                "DOWNLOAD_URL": "https://your-domain.bitrix24.com/rest/download.json?sessid=9dd90ed5a58ccc41af81f5f0043739db&token=disk%7CaWQ9NjY4NyZfPTJ5ZXdvN2Fsb09SMGw1b0FHTkRMSGR5MFJkN1pLTjNS%7CImRvd25sb2FkfGRpc2t8YVdROU5qWTROeVpmUFRKNVpYZHZOMkZzYjA5U01HdzFiMEZIVGtSTVNHUjVNRkprTjFwTFRqTlN8OWRkOTBlZDVhNThjY2M0MWFmODFmNWYwMDQzNzM5ZGIi.Lup1vDbibL6twiCPfCMFnLSoDLleNX0cfMHGv5PFaJw%3D",
                "DETAIL_URL": "https://your-domain.bitrix24.com/company/personal/user/1/drive/file/Created files/New folder for process/ava555.jpg"
            }
        }

2. Creating a Task with a File

To create a task, we use the method tasks.task.add with the following parameters:

UF_TASK_WEBDAV_FILES — specify the value n6687. This is the file ID from the result of the previous method, to which we add the prefix n for uploading the file to the field.
TITLE — the task title, a required field. Without a title, the task will not be created.
CREATED_BY — the ID of the task Creator, this field cannot be empty. If it is not filled, the Creator will automatically be the one who sends the request.
RESPONSIBLE_ID — the ID of the task Participant, a required field. Without a Participant, the task will not be created.

PHP

Python

BX24.callMethod(
            'tasks.task.add',
            {
                fields: {
                    TITLE: 'task for test',
                    RESPONSIBLE_ID: 1,
                    UF_TASK_WEBDAV_FILES: [
                        "n6687"
                    ]
                }
            }
        );

require_once('crest.php');
        
        $result = CRest::call(
            'tasks.task.add',
            [
                'fields' => [
                    'TITLE' => 'task for test',
                    'RESPONSIBLE_ID' => 1,
                    'UF_TASK_WEBDAV_FILES' => [
                        'n6687'
                    ]
                ]
            ]
        );
        
        echo '<PRE>';
        print_r($result);
        echo '</PRE>';

result = client.tasks.task.add(
            fields={
                "TITLE": "task for test",
                "RESPONSIBLE_ID": 1,
                "UF_TASK_WEBDAV_FILES": [
                    "n6687",
                ],
            }
        ).response.result

We created a task with ID 3711.

{
            "result": {
                "task": {
                    "id": "3711",
                    "parentId": null,
                    "title": "task for test",
                    "description": "",
                    "mark": null,
                    "priority": "1",
                    "multitask": "N",
                    "notViewed": "N",
                    "replicate": "N",
                    "stageId": "0",
                    "createdBy": "1",
                    "createdDate": "2024-11-02T10:06:08+02:00",
                    "responsibleId": "1",
                    "changedBy": "1",
                    "changedDate": "2024-11-02T10:06:08+02:00",
                    "statusChangedBy": null,
                    "closedBy": null,
                    "closedDate": null,
                    "activityDate": "2024-11-02T10:06:08+02:00",
                    "dateStart": null,
                    "deadline": null,
                    "startDatePlan": null,
                    "endDatePlan": null,
                    "guid": "{c2794da9-c7fe-404d-a709-ddab4578717a}",
                    "xmlId": null,
                    "commentsCount": null,
                    "serviceCommentsCount": null,
                    "allowChangeDeadline": "N",
                    "allowTimeTracking": "N",
                    "taskControl": "N",
                    "addInReport": "N",
                    "forkedByTemplateId": null,
                    "timeEstimate": "0",
                    "timeSpentInLogs": null,
                    "matchWorkTime": "N",
                    "forumTopicId": null,
                    "forumId": null,
                    "siteId": "s1",
                    "subordinate": "Y",
                    "exchangeModified": null,
                    "exchangeId": null,
                    "outlookVersion": "1",
                    "viewedDate": null,
                    "sorting": null,
                    "durationFact": null,
                    "isMuted": "N",
                    "isPinned": "N",
                    "isPinnedInGroup": "N",
                    "flowId": null,
                    "descriptionInBbcode": "Y",
                    "status": "2",
                    "statusChangedDate": "2024-11-02T10:06:08+02:00",
                    "durationPlan": null,
                    "durationType": "days",
                    "favorite": "N",
                    "groupId": "0",
                    "auditors": [],
                    "accomplices": [],
                    "checklist": [],
                    "group": [],
                    "creator": {
                        "id": "1",
                        "name": "Viola",
                        "link": "/company/personal/user/1/",
                        "icon": "https://your-domain.bitrix24.com/b13743910/resize_cache/2267/c0120a8d7c10d63c83e32398d1ec4d9e/main/c7b/c7bd44b1babaa5448125dd97d038ce1b/d5fb56b94dc2c3cd8c006a2c595a4895.jpg",
                        "workPosition": ""
                    },
                    "responsible": {
                        "id": "1",
                        "name": "Viola",
                        "link": "/company/personal/user/1/",
                        "icon": "https://your-domain.bitrix24.com/b13743910/resize_cache/2267/c0120a8d7c10d63c83e32398d1ec4d9e/main/c7b/c7bd44b1babaa5448125dd97d038ce1b/d5fb56b94dc2c3cd8c006a2c595a4895.jpg",
                        "workPosition": ""
                    },
                    "accomplicesData": [],
                    "auditorsData": [],
                    "newCommentsCount": 0,
                    "action": {
                        "accept": false,
                        "decline": false,
                        "complete": true,
                        "approve": false,
                        "disapprove": false,
                        "start": true,
                        "pause": false,
                        "delegate": true,
                        "remove": true,
                        "edit": true,
                        "defer": true,
                        "renew": false,
                        "create": true,
                        "changeDeadline": true,
                        "checklistAddItems": true,
                        "addFavorite": true,
                        "deleteFavorite": false,
                        "rate": true,
                        "edit.originator": false,
                        "checklist.reorder": true,
                        "elapsedtime.add": true,
                        "dayplan.timer.toggle": false,
                        "edit.plan": true,
                        "checklist.add": true,
                        "favorite.add": true,
                        "favorite.delete": false
                    },
                    "checkListTree": {
                        "nodeId": 0,
                        "fields": {
                            "id": null,
                            "copiedId": null,
                            "entityId": null,
                            "userId": 1,
                            "createdBy": null,
                            "parentId": null,
                            "title": "",
                            "sortIndex": null,
                            "displaySortIndex": "",
                            "isComplete": false,
                            "isImportant": false,
                            "completedCount": 0,
                            "members": [],
                            "attachments": []
                        },
                        "action": [],
                        "descendants": []
                    },
                    "checkListCanAdd": true
                }
            }
        }

In the resulting data, there is no information about the files attached to the task. To check if the file was successfully attached to the task, we will execute the method tasks.task.get with the UF_TASK_WEBDAV_FILES field in SELECT.

As a result of tasks.task.get, we will obtain the ID of the record linking the drive file to the task — this is the ID of the connection that links the task and the drive file. To get information about the file by the connection ID, we use the method drive.attachedObject.get.

Code Example

PHP

Python

// Function to upload a file
        function uploadFileToDrive() {
            // ID of the folder where you want to upload the file
            var folderId = 'your_folder_ID';
            // File name and its content in Base64 format
            var fileName = 'your_file_name';
            var fileContentBase64 = 'your_file_content_Base64';
        
            // Call the method drive.folder.uploadfile
            BX24.callMethod(
                'drive.folder.uploadfile',
                {
                    id: folderId,
                    data: {
                        NAME: fileName
                    },
                    fileContent: [
                        fileName,
                        fileContentBase64
                    ]
                },
                function(result) {
                    if (result.error()) {
                        console.error('Error uploading file:', result.error());
                    } else {
                        console.log('File uploaded successfully!', result.data());
                        var fileId = result.data().ID; // Use the ID from the result
                        createTaskWithFile(fileId);
                    }
                }
            );
        }
        
        // Function to create a task with an attached file
        function createTaskWithFile(fileId) {
            // Task parameters
            var taskTitle = 'your_task_title';
            var taskDescription = 'your_task_description';
            var responsibleId = 'your_responsible_ID';
        
            // Call the method tasks.task.add
            BX24.callMethod(
                'tasks.task.add',
                {
                    fields: {
                        TITLE: taskTitle,
                        DESCRIPTION: taskDescription,
                        RESPONSIBLE_ID: responsibleId,
                        UF_TASK_WEBDAV_FILES: ['n' + fileId] // Add prefix 'n' to the file ID
                    }
                },
                function(result) {
                    if (result.error()) {
                        console.error('Error creating task:', result.error());
                    } else {
                        console.log('Task created successfully!', result.data());
                    }
                }
            );
        }
        
        // Call the function to upload the file and create the task
        uploadFileToDrive();

require_once('crest.php');
        
        // Function to upload a file
        function uploadFileToDrive() {
            // ID of the folder where you want to upload the file
            $folderId = 'your_folder_ID';
            // Name of the file you want to upload
            $fileName = 'your_file_name';
            // Path to the file on your file system
            $filePath = '/path/to/your/file';
        
            // Read the file content and encode it in Base64
            $fileContentBase64 = base64_encode(file_get_contents($filePath));
        
            // Call the method drive.folder.uploadfile
            $result = CRest::call(
                'drive.folder.uploadfile',
                [
                    'id' => $folderId,
                    'data' => [
                        'NAME' => $fileName
                    ],
                    'fileContent' => [
                        $fileName,
                        $fileContentBase64
                    ]
                ]
            );
        
            if (isset($result['error'])) {
                echo 'Error uploading file: ' . $result['error'];
            } else {
                echo 'File uploaded successfully!';
                $fileId = $result['result']['ID']; // Use the ID from the result
                createTaskWithFile($fileId);
            }
        }
        
        // Function to create a task with an attached file
        function createTaskWithFile($fileId) {
            // Task parameters
            $taskTitle = 'your_task_title';
            $taskDescription = 'your_task_description';
            $responsibleId = 'your_responsible_ID';
        
            // Call the method tasks.task.add
            $result = CRest::call(
                'tasks.task.add',
                [
                    'fields' => [
                        'TITLE' => $taskTitle,
                        'DESCRIPTION' => $taskDescription,
                        'RESPONSIBLE_ID' => $responsibleId,
                        'UF_TASK_WEBDAV_FILES' => ['n' . $fileId] // Add prefix 'n' to the file ID
                    ]
                ]
            );
        
            if (isset($result['error'])) {
                echo 'Error creating task: ' . $result['error'];
            } else {
                echo 'Task created successfully!';
            }
        }
        
        // Call the function to upload the file and create the task
        uploadFileToDrive();

from b24pysdk import BitrixWebhook, Client
        from b24pysdk.errors import BitrixAPIError
        
        
        def upload_file_to_drive(client):
            folder_id = "your_folder_ID"
            file_name = "your_file_name"
            file_content_base64 = "your_file_content_Base64"
        
            try:
                result = client.disk.folder.uploadfile(
                    bitrix_id=folder_id,
                    data={"NAME": file_name},
                    file_content=[file_name, file_content_base64],
                ).response.result
            except BitrixAPIError as error:
                print(f"Error uploading file: {error}")
            else:
                print("File uploaded successfully!")
                file_id = result["ID"]
                create_task_with_file(client, file_id)
        
        
        def create_task_with_file(client, file_id):
            task_title = "your_task_title"
            task_description = "your_task_description"
            responsible_id = "your_responsible_ID"
        
            try:
                client.tasks.task.add(
                    fields={
                        "TITLE": task_title,
                        "DESCRIPTION": task_description,
                        "RESPONSIBLE_ID": responsible_id,
                        "UF_TASK_WEBDAV_FILES": [f"n{file_id}"],
                    },
                ).response
            except BitrixAPIError as error:
                print(f"Error creating task: {error}")
            else:
                print("Task created successfully!")
        
        
        client = Client(
            BitrixWebhook(
                domain="your-domain.bitrix24.com",
                auth_token="your-webhook-token",
            )
        )
        
        upload_file_to_drive(client)