HttpPostBytesSender.java

package org.sef4j.core.helpers.senders.http;

import java.io.IOException;
import java.io.OutputStream;
import java.net.HttpURLConnection;
import java.net.URL;
import java.util.Collection;
import java.util.Map;

import org.sef4j.core.api.EventSender;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

/**
 * EventSender for sending byte[] as http POST requests
 * 
 * <PRE>         EventSender(byte[])           
 *              +---------------------+
 * sendEvent    |    - toURL          |      http POST /url
 *  ----->      |    - headers        |   --------------------->           Http Server           
 *  byte[]      |    - pooledCon      |        Content-Type=contentType       (Elasticsearch, InfluxDB, MongoDB, others ...)
 *              +---------------------+        .
 *                                             "byte[]..."
 * </PRE>
 */
public class HttpPostBytesSender implements EventSender<byte[]> {
    
    private static final Logger LOG = LoggerFactory.getLogger(HttpPostBytesSender.class);
    
    public static final String CONTENT_TYPE_JSON = "application/json";

    private String displayName;
    
	private URL toURL;
	
	private String contentType;
	private Map<String,String> headers;
	
	// ?? may keep open connection with java.net.HttpURLConnection
	private boolean closeImmediateCon = true;  
	private HttpURLConnection pooledCon;
	
    // ------------------------------------------------------------------------
    
    public HttpPostBytesSender(String displayName, URL toURL, String contentType, Map<String,String> headers) {
        this.displayName = displayName;
        this.toURL = toURL;
        this.contentType = contentType;
        this.headers = headers;
    }

    // ------------------------------------------------------------------------
    
    public void sendEvent(byte[] data) {
        HttpURLConnection con = openHttpURLConnection();
        try {
            doSendContent(con, data);
        } finally {
            releaseHttpURLConnection(con);
        }
    }
    
    public void sendEvents(Collection<byte[]> datas) {
        HttpURLConnection con = openHttpURLConnection();
        try {
            for(byte[] data : datas) {
                doSendContent(con, data);
            }
        } finally {
            releaseHttpURLConnection(con);
        }
    }
    
    protected void doSendContent(HttpURLConnection con, byte[] data) {
        try {
            con.setDoOutput(true);
            con.setRequestMethod("POST");
            if (contentType != null) {
                con.setRequestProperty("Content-Type", contentType);
            }
            if (headers != null) {
                for(Map.Entry<String,String> e : headers.entrySet()) {
                    con.setRequestProperty(e.getKey(), e.getValue());
                }
            }
            
            OutputStream conOutput = con.getOutputStream();
            
            conOutput.write(data);
            
            conOutput.close();
            
            // con.setReadTimeout(10000);
            int responseCode = con.getResponseCode();
            if (responseCode == 200) {
                // OK!
            } else {
                String responseMsg = con.getResponseMessage();
                throw new RuntimeException("Failed to POST json to '" + displayName + "', response code:" + responseCode + " msg:" + responseMsg);
            }
            
        } catch(IOException ex) {
            throw new RuntimeException("Failed to POST json to '" + displayName + "', ex:" + ex.getMessage());
        }
    }

    protected HttpURLConnection openHttpURLConnection() {
        HttpURLConnection con;
        if (pooledCon != null) {
            con = pooledCon;
        } else {
            try {
                con = (HttpURLConnection) toURL.openConnection();
                pooledCon = con;
            } catch(IOException ex) {
                // do not display real seriesURL...it contains user/password!
                LOG.warn("Failed to connect to '" + displayName + "', ex:" + ex.getMessage() + " ... rethrow"); 
                throw new RuntimeException("Failed to connect to '" + displayName +"'", ex);
            }
        }
        return con;
    }
    
    protected void releaseHttpURLConnection(HttpURLConnection con) {
        if (con != null) {
            if (closeImmediateCon) {
                pooledCon = null;
                try {
                    con.disconnect();
                } catch(Exception ex) {
                    // ignore, no rethrow!
                }
            }
        }
    }
}