# Preview file

Preview files as inline content.

```text
POST https://moi.matrixorigin.cn/newmoi/catalog/file/preview_stream
```

## Preparation before calling

First [query the file list](list-files.md) to obtain the target file ID. Prepare the personal access token, target workspace ID, and file ID that have access to the target workspace.

The example below uses:

- `$AI_STUDIO_API_KEY`: The actual personal access token, passed through the `X-API-Key` Header.
- `$WORKSPACE_ID`: Target workspace ID, passed through `X-Workspace-ID` Header.
- `$FILE_ID`: File ID to preview.
- `$VOLUME_ID`: The data volume ID where the target file is located.

The caller requires read access to the root volume.

## Request example

```bash
curl -X POST "https://moi.matrixorigin.cn/newmoi/catalog/file/preview_stream" \
  -H "X-API-Key: $AI_STUDIO_API_KEY" \
  -H "X-Workspace-ID: $WORKSPACE_ID" \
  -H 'Content-Type: application/json' \
  -d '{
    "volume_id": "'"$VOLUME_ID"'",
    "file_id": "'"$FILE_ID"'"
  }'
```

## Request body

| Parameter | Type | Required | Description |
| --- | --- | --- | --- |
| `file_id` | string | Yes | File ID. |
| `volume_id` | string | Yes | The ID of the data volume where the file is located. |

## Successful response

On success, `200` is returned, the response body is the file content, and `Content-Disposition: inline` is used. The caller requires read access to the root volume.

The response is not a JSON envelope. Content type of the service settings file; `application/octet-stream` is used when not provided. If a filename is available, the response header also contains `Content-Disposition: inline`.

| Response items | Description |
| --- | --- |
| HTTP status code | `200`. |
| `Content-Type` | File MIME type; `application/octet-stream` when not provided. |
| `Content-Disposition` | Displayed inline when filename is available. |
| Response body | File binary content. |

## Error response

When the preview fails before starting, the response uses a JSON error envelope:

```json
{
  "code": "ErrNotFound",
  "msg": "对象不存在",
  "data": null
}
```

### Common HTTP errors

```{list-table}
:header-rows: 1
:widths: 12 22 32 34

* - HTTP status code
  - error code
  - Common causes
  - Recommended actions
* - `400`
  - `ErrParamInvalid`
  - `file_id` is missing or the request body is invalid.
  - Pass in a valid file ID.
* - `403`
  - `ErrForbidden`
  - The current identity does not have read permission on the root volume to which it belongs.
  - Use credentials with read access, or contact your administrator for authorization.
* - `404`
  - `ErrNotFound`
  - File does not exist.
  - Check file ID.
* - `500`
  - `ErrServer`
  - The service cannot open the file preview stream.
  - Record the request time and error message and try again; if it continues to fail, contact support.
```

## Follow-up operations

After completion, [Query Catalog details](get-catalog.md) confirms the result.