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. |
Authorization |
Mandatory |
String |
Access Token, by the format of Bearer xxx. How to get the Access Token >> |
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. |
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. |
Error Code¶
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 channelId = "yourChannelId";
private static String url = "https://{domain_url}";
private static String token = "";
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;
}
}
public static String getToken() {
Request request = new Request();
request.setMethod("POST");
long timestamp = System.currentTimeMillis();
String temp = accessKey + timestamp + secretKey;
request.bodyParams().put("encryption", string2Sha256(temp).toLowerCase());
request.bodyParams().put("timestamp", timestamp);
request.bodyParams().put("appKey", accessKey);
try {
JSONObject response = Poseidon.config(PConfig.init().appKey(accessKey).appSecret(secretKey).debug())
.url(url + "/apim-token-service/v2.0/token/get")
.getResponse(request, JSONObject.class);
return response.getJSONObject("data").getString("accessToken");
} catch (Exception e) {
e.printStackTrace();
}
return null;
}
private static String string2Sha256(String str) {
MessageDigest messageDigest;
String encodeStr = "";
try {
messageDigest = MessageDigest.getInstance("SHA-256");
byte[] hash = messageDigest.digest(str.getBytes(StandardCharsets.UTF_8));
encodeStr = Hex.encodeHexString(hash);
} catch (NoSuchAlgorithmException e) {
}
return encodeStr;
}
@Test
public void ReadData() {
token = getToken();
Request request = new Request();
request.setQueryParam("orgId", orgId);
request.setMethod("POST");
request.headerParams().put(HttpHeaders.AUTHORIZATION, "Bearer " + token);
request.headerParams().put(HttpHeaders.CONTENT_TYPE, "application/json");
request.setBodyParams("sqlQuery", "show schemas");
request.setBodyParams("queue", null);
request.setBodyParams("itemFormat", null);
JSONObject response = Poseidon.config(PConfig.init().appKey(accessKey).appSecret(secretKey))
.url(url + "/data-federation/v2.0/channels/read/" + channelId)
.getResponse(request, JSONObject.class);
System.out.println(response);
}
}