64 lines
1.7 KiB
Java
64 lines
1.7 KiB
Java
package netpp.client;
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import java.io.ByteArrayInputStream;
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import java.io.IOException;
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import javax.json.Json;
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import javax.json.JsonArray;
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import javax.json.JsonObject;
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import javax.json.JsonReader;
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import org.eclipse.californium.core.CoapClient;
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import org.eclipse.californium.core.CoapResponse;
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import org.eclipse.californium.elements.exception.ConnectorException;
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public class Main {
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public static void main(String[] args) {
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if (args.length < 1) {
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System.err.println("[F] Bad parameters");
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System.err.println("Usage: ");
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System.err.println("$ exe <url>");
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System.err.println();
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System.err.println("Example:");
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System.err.println("$ exe coap://[2001:db8::0]/urn:it.unipi.ing.ce.netpp:c00000003");
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System.exit(1);
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}
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/* getting parameter from CLI */
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final String url = args[0];
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/* subscribe to every node specified */
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System.err.println("[I] GET " + url);
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CoapClient client = new CoapClient(url);
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CoapResponse response = null;
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try {
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response = client.get();
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if (!response.isSuccess()) {
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System.err.println("[E] can not access resource");
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System.exit(1);
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}
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} catch (ConnectorException | IOException e) {
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e.printStackTrace();
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System.exit(1);
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}
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/* parse SenML JSON */
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byte[] payload = response.getPayload();
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ByteArrayInputStream bis = new ByteArrayInputStream(payload);
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JsonReader reader = Json.createReader(bis);
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JsonArray senml = reader.readArray();
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JsonObject measurement = senml.getJsonObject(0);
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String resourceName = measurement.getString("n");
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int resourceValue = measurement.getInt("v");
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/* output result */
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System.out.println("Read Resource");
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System.out.println("name: " + resourceName);
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System.out.println("value: " + resourceValue);
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System.exit(0);
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}
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}
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