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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

Device Requesting a URL for File Download

Updated on 2024-12-02 GMT+08:00

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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.

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.

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

Previous topic: Device Reporting File Upload Results

Next topic: Platform Delivering a Temporary URL for File Download

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