Upload a File to the Task task.item.addfile

curl -X POST \
        -H "Content-Type: application/json" \
        -H "Accept: application/json" \
        -d '{"TASK_ID":"140","FILE":{"NAME":"desc.txt","CONTENT":"BASE64_ENCODED_CONTENT_OF_DESC.TXT"},"auth":"z3eamwwkpgl7u18kx14q1s4c0ffckqsn"}' \
        https://**put_your_bitrix24_address**/rest/task.item.addfile
        

// This snippet is an ES module: top-level await requires type="module" or a bundler.
        // $b24 is an already-initialized SDK instance (see the SDK "Get started" guide).
        import { Text } from '@bitrix24/b24jssdk'
        import type { B24Frame } from '@bitrix24/b24jssdk'
        
        declare const $b24: B24Frame
        
        // TODO: verify API version — the page does not show a JSON response example
        // Shape of the payload returned in result (ID of the uploaded file)
        type AddFileResult = number
        
        try {
          const response = await $b24.actions.v2.call.make<AddFileResult>({
            method: 'task.item.addfile',
            params: {
              TASK_ID: '140',
              FILE: {
                NAME: 'desc.txt',
                CONTENT: 'BASE64_ENCODED_CONTENT_OF_DESC.TXT',
              },
            },
            requestId: Text.getUuidRfc4122()
          })
        
          // The payload is available only on a successful response
          if (!response.isSuccess) {
            console.error(response.getErrorMessages().join('; '))
          } else {
            const result = response.getData()!.result
            console.info('Uploaded file ID:', result)
          }
        } catch (error) {
          // Thrown on transport or SDK failures (AjaxError, SdkError, etc.)
          console.error(error)
        }
        

<!-- Load the SDK (UMD build); it is exposed as the global B24Js -->
        <script src="https://unpkg.com/@bitrix24/b24jssdk@1/dist/umd/index.min.js"></script>
        <script>
          async function addFileToTask() {
            try {
              // Initialize the SDK inside a Bitrix24 frame
              const $b24 = await B24Js.initializeB24Frame()
        
              const response = await $b24.actions.v2.call.make({
                method: 'task.item.addfile',
                params: {
                  TASK_ID: '140',
                  FILE: {
                    NAME: 'desc.txt',
                    CONTENT: 'BASE64_ENCODED_CONTENT_OF_DESC.TXT',
                  },
                },
                requestId: B24Js.Text.getUuidRfc4122()
              })
        
              // The payload is available only on a successful response
              if (!response.isSuccess) {
                console.error(response.getErrorMessages().join('; '))
                return
              }
        
              const result = response.getData().result
              console.info('Uploaded file ID:', result)
            } catch (error) {
              // Thrown on transport or SDK failures (AjaxError, SdkError, etc.)
              console.error(error)
            }
          }
        
          document.addEventListener('DOMContentLoaded', addFileToTask)
        </script>
        

try {
            $response = $b24Service
                ->core
                ->call(
                    'task.item.addfile',
                    [
                        'TASK_ID' => '140',
                        'FILE'    => [
                            'NAME'    => 'desc.txt',
                            'CONTENT' => 'BASE64_ENCODED_CONTENT_OF_DESC.TXT',
                        ],
                    ]
                );
        
            $result = $response
                ->getResponseData()
                ->getResult();
        
            if ($result->error()) {
                error_log($result->error());
                echo 'Error: ' . $result->error();
            } else {
                echo 'Success: ' . print_r($result->data(), true);
            }
        
        } catch (Throwable $e) {
            error_log($e->getMessage());
            echo 'Error adding file to task: ' . $e->getMessage();
        }
        

BX24.callMethod(
            "task.item.addfile",
            {
                TASK_ID: "140",
                FILE: {
                    NAME: "desc.txt",
                    CONTENT: "BASE64_ENCODED_CONTENT_OF_DESC.TXT"
                }
            },
            function(result) {
                if(result.error())
                    console.error(result.error());
                else
                    console.log(result.data());
            }
        );
        

require_once('crest.php');
        
        $result = CRest::call(
            'task.item.addfile',
            [
                'TASK_ID' => "140",
                'FILE' => [
                    'NAME' => 'desc.txt',
                    'CONTENT' => base64_encode(file_get_contents($_SERVER['DOCUMENT_ROOT'] .'/desc.txt'))
                ]
            ]
        );
        
        echo '<PRE>';
        print_r($result);
        echo '</PRE>';