Read Data¶

Read data by providing SQL query through the specified channel.

Prerequisites¶

Read channels are created and started in the organization.

Request Format¶

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

Request Parameters (Header)¶

Name	Mandatory/Optional	Data Type	Description
Content-Type	Mandatory	String	Content or file type. The default value is application/json.

Request Parameters (URI)¶

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

Request Parameters (Body)¶

Name	Mandatory/Optional	Data Type	Description
sqlQuery	Mandatory	String	SQL query for getting data from storage systems.
source	Optional	String	For channels with cross-source analysis disabled, specify the alias of the data source.
queue	Optional	String	Specify the priority of the data query job. Options are Hot, Warm, and Cold.
itemFormat	Optional	String	Reserved parameter for specifying the format of returned JSON.

Response Parameters¶

Name	Data Type	Description
data	List<Object>	Data that is returned by the SQL query. For more information, see Returned Data Struct

Returned Data Struct¶

Name	Data Type	Description
columns	String	Column name.
metadata	String	Meta data.
queryState	String	Data querying state.
rows	List<Object>	Rows of data. For more information, see Data Row Struct

Data Row Struct¶

Name	Data Type	Description
COLUMN_NAME	String	Column name.
DATA_TYPE	String	Data type.
IS_NULLABLE	String	Data type.

Sample¶

Request Sample¶

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

method: POST

requestBody:
{
  "sqlQuery": "show schemas"
}

Return Sample¶

{
    "msg": "OK",
    "code": 0,
    "data": {
        "metadata": ["VARCHAR"],
        "columns": ["SCHEMA_NAME"],
        "queryState": "COMPLETED",
        "rows": []
    }
}

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;

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 readData() throws InterruptedException {
        Request request = new Request();
        request.setQueryParam("orgId", orgId);
        request.setMethod("POST");
        request.headerParams().put(HttpHeaders.CONTENT_TYPE, "application/json");
        request.setBodyParams("sqlQuery", "show schemas");
        //For channels with cross-source analysis disabled, specify the data source alias.
        //request.setBodyParams("source", "customerMysql");
        request.setBodyParams("queue", null);
        request.setBodyParams("itemFormat", null);
        try {
            JSONObject response = Poseidon.config(PConfig.init().connectTimeout(0).readTimeout(0).writeTimeout(0).appKey(accessKey).appSecret(secretKey).debug())
                    .url(url + "/data-federation/v2.0/channels/read/" + chId)
                    .getResponse(request, JSONObject.class);
            System.out.println(response);
        } catch (Exception e) {
            e.printStackTrace();
        }

        System.out.println(System.currentTimeMillis());

    }
}