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• Create Download Request

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

Callback Request Struct

Name	Data Type	Description
id	String	Download task ID.
returnCode	String	0: Download succeeded, and the returned URL is for downloading data. Not 0: Download failed, and the returned URL is for error log.
download_url	String	Upon success, return the file download URL.
log_url	String	Upon failure, return the error log URL.
dataSize	String	Data file size.

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"
  }
}

Java SDK Sample

import com.alibaba.fastjson.JSONObject;
import com.envision.apim.poseidon.config.PConfig;
import com.envision.apim.poseidon.core.Poseidon;
import com.envision.apim.poseidon.request.PoseidonRequest;
import com.google.common.net.HttpHeaders;
import org.apache.commons.codec.binary.Hex;
import org.junit.Test;

import java.nio.charset.StandardCharsets;
import java.security.MessageDigest;
import java.security.NoSuchAlgorithmException;
import java.util.HashMap;

public class Sample {

    private static String accessKey = "AccessKey of your APP";
    private static String secretKey = "SecretKey of your APP";
    private static String orgId = "yourOrgId";
    private static String chId = "yourChannelId";
    private static String url = "https://{domain_url}";

    private static class Request extends PoseidonRequest {

        public void setQueryParam(String key, Object value) {
            queryEncodeParams().put(key, value);
        }

        public void setMethod(String method) {
            this.method = method;
        }

        public void setBodyParams(String key, Object value) {
            bodyParams().put(key, value);
        }

        private String method;

        @Override
        public String baseUri() {
            return "";
        }

        @Override
        public String method() {
            return method;
        }
    }

    @Test
    public void downloadRequest() {
        Request request = new Request();
        request.setQueryParam("orgId", orgId);
        request.setMethod("POST");
        request.setBodyParams("taskName", "yourTaskName");
        request.setBodyParams("sourceName", "hive_enos");
        request.setBodyParams("querySql", "select * from students");
        request.setBodyParams("filePackageName", "studentsOpenAPI");
        request.setBodyParams("callbackURL", "http://localhost:8080");
        request.setBodyParams("selfDefineQueuePara", "set mapreduce.map.memory.mb=1024;set mapreduce.reduce.memory.mb=2048");
        Map<String, Object> files = new HashMap<>();
        files.put("split", true);
        files.put("encoding", "utf-8");
        files.put("delimiter", ",");
        List<String> fileHeaders = new ArrayList<>();
        fileHeaders.add("c1");
        fileHeaders.add("c2");
        files.put("fileHeader", fileHeaders);
        Map<String, String> fileRename = new HashMap<>();
        fileRename.put("1", "group1");
        fileRename.put("2", "group2");
        files.put("fileRename", fileRename);
        request.setBodyParams("files", files);
        try {
            JSONObject response = Poseidon.config(PConfig.init().appKey(accessKey).appSecret(secretKey))
                    .url(url + "/data-federation/v2.0/channels/read/" + chId + "/download-request")
                    .getResponse(request, JSONObject.class);
            System.out.println(response);
        } catch (Exception e) {
            e.printStackTrace();
        }
    }
}