##### Brief description

Check if the file exists on the target device. If it does, return relevant information about the file. If the same file exists, do not upload it to save time.

##### Request URL

Interface address (case must be consistent)

- `http://192.168.1.x/check`

##### Request method

- GET

##### Request message example

```http
GET /check?file_path=files/test/2C0547E35BA5.jpg&sign=6B1C08604C09C08AF80DD251E019**** 
HTTP/1.1
Host: 192.168.1.x
Accept: */*
Content-Type: application/x-www-form-urlencoded; charset=UTF-8
```

##### Parameters

| Parameter Name | Required | Type | Example | Description |
| --- | --- | --- | --- | --- |
| `file_path` | Yes | string | `files/test/2C0547E35BA5.jpg` | The storage path of the file on the target device |
| `sign` | Yes | string | `1E3B1050FBE6F1B53B4F858CD8E39***` | The signature value calculated through the signature algorithm |

##### Return message example

```http
HTTP/1.1 200 OK
Content-Length: 50
Content-Type: application/json; charset=utf-8
```

##### Example of returning content

```json
{"STATE":"SUCCEED","MD5":"3F73ACFDE47DBF4C98E65D3D7019F8AE","Length":47733}
{"STATE":"ERROR","message":"file does not exist"}
```

##### Return content field description

| Parameter Name | Type | Example | Description |
| --- | --- | --- | --- |
| `STATE` | string | `SUCCEED` or `ERROR` | Business status |
| `message` | string | file does not exist | Status description, returned when `STATE` = `ERROR` |
| `MD5` | string | 3F73ACFDE47DBF4C98E65D3D7019F8AE | File MD5, returned when `STATE` = `SUCCEED` |
| `Length` | int | 47733 | File length, returned when `STATE` = `SUCCEED` |