Example HTTP Get Request

He is an example that will make a HttpGet request and logging the response. The response text is printed to the screen and captured to a file. An human readable format of the bytes are also logged to a file

package httprequesttest;

import com.integpg.system.JANOS;
import java.io.FileOutputStream;
import java.io.IOException;

public class HttpRequestTest {

    public static void main(String[] args) {
        System.out.println("args.length: " + args.length);

        if (0 < args.length) {
            try {
                //
                // get the server hostname from the command line arguments
                String hostname = args[0];
                String serviceName = args[1];
                String paramsString = "";
                if (3 == args.length) paramsString = args[2];

                //
                // define our get job status request
                String urlString = String.format("http://%s/%s?%s", hostname, serviceName, paramsString);
                System.out.println("Testing call to " + urlString);

                //
                // define our http object and perform the request
                HttpURL url = new HttpURL(urlString);
                HttpRequest httpRequest = new HttpRequest(url);
                HttpResponse httpResponse = httpRequest.sendRequest();
                httpResponse.processResponse();
                String response = httpResponse.getData();

                //
                // print the response and toss the response in a file
                System.out.println("httpResponse: " + response);
                writeAllBytes("response.txt", response.getBytes());
                writeAllBytes("response.bin", hexDump(response.getBytes()).getBytes());
            } catch (IOException ex) {
                ex.printStackTrace();
            }

        } else {
            System.out.println("a url must be supplied");
        }
    }


/**
 * HELPER FUNCTIONS
 */
    public static void writeAllBytes(String filename, byte[] bytes) throws IOException {
        FileOutputStream fos = null;
        try {
            fos = new FileOutputStream(filename);
            fos.write(bytes);
            fos.flush();
        } catch (Exception ex) {
            JANOS.syslog("writeAllBytes to " + filename + " threw " + ex.getMessage(), JANOS.SYSLOG_ERROR);
        } finally {
            try {
                if (null != fos) fos.close();
            } catch (IOException ex1) {
                ex1.printStackTrace();
            }
        }
    }

    public static final char[] LowerHexArray = { '0', '1', '2', '3', '4', '5', '6', '7', '8', '9', 'a', 'b', 'c', 'd', 'e', 'f' };



    public static String hexDump(byte[] bytes) {
        return hexDump(bytes, 0, bytes.length);
    }



    public static String hexDump(byte[] bytes, int offset, int length) {
        StringBuilder sb = new StringBuilder((length / 16 + 1) * 83);

        char[] line = new char[81];
        line[0] = '0';
        line[1] = 'x';
        line[line.length - 2] = '\r';
        line[line.length - 1] = '\n';

        int endAddress = offset + length;
        for (int lineAddress = offset - (offset % 16); lineAddress < endAddress; lineAddress += 16) {
            int charPos = 2;
            line[charPos++] = LowerHexArray[(lineAddress >> 12 & 0x0F)];
            line[charPos++] = LowerHexArray[(lineAddress >> 8 & 0x0F)];
            line[charPos++] = LowerHexArray[(lineAddress >> 4 & 0x0F)];
            line[charPos++] = LowerHexArray[lineAddress & 0x0F];
            line[charPos++] = ' ';
            line[charPos++] = ' ';
            line[charPos++] = ' ';

            for (int linePos = 0; linePos < 16; linePos++) {
                int address = lineAddress + linePos;
                if (address < offset) {
                    line[charPos++] = ' ';
                    line[charPos++] = ' ';
                    line[charPos++] = ' ';
                } else if (address < endAddress) {
                    int c = bytes[address];
                    line[charPos++] = LowerHexArray[(c >> 4 & 0x0F)];
                    line[charPos++] = LowerHexArray[c & 0x0F];
                    line[charPos++] = ' ';
                } else {
                    line[charPos++] = ' ';
                    line[charPos++] = ' ';
                    line[charPos++] = ' ';
                }

                if (7 == linePos) {
                    // add 2 spaces between each group of 8 bytes
                    line[charPos++] = ' ';
                    line[charPos++] = ' ';
                }
            }
            // add 3 spaces between the second group of 8 bytes and the ASCII output
            line[charPos++] = ' ';
            line[charPos++] = ' ';
            line[charPos++] = ' ';

            for (int linePos = 0; linePos < 16; linePos++) {
                int address = lineAddress + linePos;

                if (address < offset) line[charPos++] = ' ';
                else if (address < endAddress) {
                    char c = (char) bytes[address];
                    if (0x20 > c || 0x80 <= c) line[charPos++] = '.';
                    else line[charPos++] = c;
                } else line[charPos++] = ' ';
                if (7 == linePos) line[charPos++] = ' ';
            }

            sb.append(line, 0, line.length);
        }

        return sb.toString();
    }
}

HttpRequest.java

package httprequesttest;

import java.io.IOException;
import java.io.InputStream;
import java.io.OutputStream;
import java.net.InetAddress;
import java.net.Socket;
import java.net.SocketException;
import java.util.Enumeration;
import java.util.Hashtable;

public class HttpRequest {

    private final HttpURL _url;
    private Socket _socket;
    private String _type = "GET";
    private byte[] _data;
    private final Hashtable<String, String> _userHeaders = new Hashtable<String, String>();



    public HttpRequest(HttpURL url) {
        _url = url;
    }



    public String getRequestMethod() {
        return _type;
    }



    public void setRequestMethod(String type) {
        _type = type;
    }



    public void addHeader(String name, String value) {
        _userHeaders.put(name, value);
    }



    public void setData(byte[] data) {
        _data = data;
    }



    public HttpResponse sendRequest() throws IOException {
        InetAddress resolvedAddress = InetAddress.getByName(_url.getHost());
        _socket = new Socket(resolvedAddress.getHostAddress(), _url.getPort());
        _socket.setSoTimeout(15000);

        if (-1 != _url.toString().toLowerCase().indexOf("https")) {
            System.out.println("set secure");
            _socket.setSecure(true);
        }

//        System.out.print("Request:\r\n");
        sendHeaders();
        if (null != _data) {
            sendData();
        }

        return new HttpResponse(this);
    }



    private void sendHeaders() throws IOException {
        OutputStream out = getOutputStream();
        String headers
                = _type + " /" + _url.getFile() + _url.getQuery() + " HTTP/1.1\r\n"
                + "Host: " + _url.getHost() + "\r\n"
                + "Connection: close\r\n"
                + "Pragma: no-cache\r\n"
                + "Cache-Control: no-cache\r\n";

        if (null != _data) {
            headers += "Content-Length: " + _data.length + "\r\n";
        } else {
            headers += "Content-Length: 0\r\n";
        }

        if (0 < _userHeaders.size()) {
            Enumeration headerEnumeration = _userHeaders.keys();
            while (headerEnumeration.hasMoreElements()) {
                String name = (String) headerEnumeration.nextElement();
                String value = _userHeaders.get(name);
                headers += name + ": " + value + "\r\n";
            }
        }

        out.write((headers + "\r\n").getBytes());
        out.flush();
    }



    private void sendData() throws IOException {
        if (null != _data) {
            OutputStream out = getOutputStream();
            out.write(_data);
            out.flush();
        }
    }



    public OutputStream getOutputStream() throws SocketException, IOException {
        if (_socket == null) throw new SocketException("Socket not yet connected");
        return _socket.getOutputStream();
    }



    public InputStream getInputStream() throws SocketException, IOException {
        if (_socket == null) throw new SocketException("Socket not yet connected");
        return _socket.getInputStream();
    }



    public void close() throws IOException {
        if (null != _socket) {
            System.out.println("close HTTPRequest");
            if (null != getInputStream()) getInputStream().close();
            if (null != getOutputStream()) getOutputStream().close();
            _socket.close();
        }
    }

}

By | On October 7, 2019 1:22 pm | No Comments | Categorized in: , ,