Help Center/ IoT Device Access/ API Reference/ MQTT or MQTTS API Reference on the Device Side/ File Upload and Download/ Device Requesting a URL for File Download
Updated on 2024-12-02 GMT+08:00
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Device Requesting a URL for File Download

Function

This API is used by a device to report a request for obtaining a URL for file download.

Topic

Upstream: $oc/devices/{device_id}/sys/events/up

Parameters

Parameter

Mandatory/Optional

Type

Description

object_device_id

Optional

String

Explanation:

  • Mandatory when the child device reports data during the gateway device data reporting. Specify object_device_id as the child device ID of the device in the topic. Otherwise, the request fails.
  • When a directly connected device reports data, the value of object_device_id must be the same as that of device_id in the topic.
  • If this parameter is left blank, the value of this parameter is the same as that of device_id in the topic by default.

services

Optional

List<ServiceEvent>

Explanation:

List of services that an event is about.

ServiceEvent structure

Parameter

Mandatory/Optional

Type

Description

service_id

Mandatory

String

Explanation:

System field.

Value range:

Fixed at $file_manager.

event_type

Mandatory

String

Explanation:

System field.

Value range:

Fixed at get_download_url.

event_time

Optional

String

Explanation:

Event time. UTC time format: yyyyMMdd'T'HHmmss'Z'.

If this parameter is not carried in the reported data or is in incorrect format, the time when the platform receives the data is used.

paras

Mandatory

Object

Explanation:

Event parameters in JSON format.

paras structure

Parameter

Mandatory/Optional

Type

Description

fileName

Mandatory

String

Explanation:

Name of the file to be downloaded.

file_attributes

Optional

Object

Explanation:

File attributes, which are objects in JSON format.

Example

Topic: $oc/devices/{device_id}/sys/events/up  
Data format:
{ 
    "object_device_id": "{object_device_id}", 
    "services": [{ 
        "service_id": "$file_manager", 
        "event_type": "get_download_url", 
        "event_time": "20151212T121212Z",
         "paras": { 
            "file_name": "a.jpg",
            "file_attributes": {
                "hash_code": "58059181f378062f9b446e884362a526",
                "size": 1024
            }
         } 
    }] 
}
Parent topic: File Upload and Download