Create Download Request¶

Create a file download task.

Prerequisites¶

A read channel for downloading files is already started and running, and the channel must have the cross-source analysis function disabled. For more information, see Downloading Files.

Request Format¶

POST https://{apigw-address}/data-federation/v2.0/channels/read/{channelId}/download-request

Request Parameters (URI)¶

Name	Location (Path/Query)	Mandatory/Optional	Data Type	Description
orgId	Query	Mandatory	String	The organization ID. How to get the orgId>>
channelId	Path	Mandatory	String	Channel ID.

Request Parameters (Body)¶

Name	Mandatory/Optional	Data Type	Description
taskName	Mandatory	String	Specify the name of the file download task.
sourceName	Mandatory	String	Specify the data source alias (currently supporting HIVE(EnOS) data source).
querySql	Mandatory	String	Specify the SQL statement for downloading files.
filePackageName	Mandatory	String	Specify name of the downloaded file.
files	Optional	List<JSONObject>	Configuration of the downloaded file. For details, see File Configuration Struct
callbackURL	Optional	String	Call back the downlaod result with POST method. For details of the response parameters, see Download Task Callback Request Struct
selfDefineQueuePara	Optional	String	Specify Hive downloading task parameters, separated by `;`.

File Configuration Struct¶

Name	Mandatory/Optional	Data Type	Description
split	Mandatory	Boolean	Specify whether to enable partition for the downloaded file (true: enable partition; false: disable partition).
encoding	Mandatory	String	Specify the file encoding method (options are utf-8 and gbk).
delimiter	String	Boolean	Specify the field delimiter (options are `\t`, `,`, and `;`).
fileHeader	Mandatory	List<String>	Specify the file table header, separated by `,`.
fileRename	Optional	List<JSONObject>	When enabling partition for the downloaded file, specify file part names. For details, see File Rename Struct

File Rename Struct¶

Name	Mandatory/Optional	Data Type	Description
file1	Mandatory	String	Specify the file part name.
file2	Mandatory	String	Specify the file part name.
file3	Mandatory	String	Specify the file part name.

Response Parameters¶

Name	Data Type	Description
data	List<JSONObject>	Return the information of downloaded file, see Task ID Struct

Task ID¶

Name	Data Type	Description
taskId	String	ID of the created file download task.

Samples¶

Request Sample¶

url: https://{apigw-address}/data-federation/v2.0/channels/read/{channelId}/download-request?orgId={}

method: POST

request body：

{
  "taskName": "test_federation_download_openapi",
  "sourceName": "hive_enos"
  "querySql": "select * from students",
  "filePackageName": "studentsOpenAPI",
  "callbackURL":"http://localhost:8080",
  "selfDefineQueuePara":"set mapreduce.map.memory.mb=1024;set mapreduce.reduce.memory.mb=2048",
  "files": {
    "split": true,
    "encoding": "utf-8",
    "delimiter": ",",
    "fileHeader": [
      "c1",
      "c2",
      "c3",
      "c4",
      "c5",
      "c6"
    ],
    "fileRename": {
      "1": "group1",
      "2": "group2",
      "3": "group3",
      "4": "group4"
    }
  }
}

Return Sample¶

{
  "msg": "OK",
  "code": 0,
  "data": {
    "taskId": "3049d82e949e47958246ff0136a77fba"
  }
}

SDK Samples¶

You can access the SDK samples for data federation service on GitHub:

Java
Python