I would like to implement a simple web server in java.
The problem is that images are not correctly rendered on the web browser; all I can see, if I go to localhost:8888/image.png, is a white square with exact width, height and weight.
Thank you in advance! :)
Here is the code:
public Http(Socket server) throws IOException {
in = new BufferedReader(new InputStreamReader(server.getInputStream()));
parseHeader(in);
String response = new String();
out = new PrintWriter(server.getOutputStream(), true);
Files f = new Files(getHomePath() + httpRequestedPage);
if(!f.exists) {
// 404 ERROR
} else {
response += "HTTP/1.1 200 OK\r\n";
response += "Date: " + nowDate + "\r\n";
response += "Content-Type: image/png\r\n";
response += "Content-Length: " + res.length() + "\r\n";
response += "Connection: keep-alive\r\n";
response += "\r\n";
response += IOUtils.toString(new FileInputStream(getHomePath() + httpRequestedPage));
}
out.println(response);
in.close();
out.close();
}
EDIT:
Unfortunately it returns the same message.
out = new PrintWriter(server.getOutputStream(), true);
OutputStream out2 = server.getOutputStream();
File file = new File(HttpServer.getHomePath() + httpRequestedPage);
InputStream stream = new FileInputStream(file);
String response = new String();
response += "HTTP/1.1 200 OK\r\n";
response += "Date: " + nowDate + "\r\n";
response += "Content-Type: image/png\r\n";
response += "Content-Length: " + file.length() + "\r\n";
response += "Connection: keep-alive\r\n";
response += "\r\n";
out.println(response);
IOUtils.copy(stream, out2);
out.close();
out2.close();
You are using Write class for rendering the image. Use the OutputStream to write the image. Images are bytes and always byte based streams should be used to render them.
If you are converting bytes into String then you must use Base64 encoding. And on the client side you can specify the image src similar to this "data:image/png;base64," + imageData.
Related
I am trying to upload two images along with some parameters to a server through my android application. After having searched online and following the instructions from here and here, as well as other sources, I have the following code:
String boundary = "***" + System.currentTimeMillis() + "***";
String twoHyphens = "--";
String crlf = "\r\n";
String output = "";
try {
HttpURLConnection httpUrlConnection = null;
URL url = new URL(myUrl);
httpUrlConnection = (HttpURLConnection) url.openConnection();
httpUrlConnection.setUseCaches(false);
httpUrlConnection.setDoInput(true);
httpUrlConnection.setDoOutput(true);
httpUrlConnection.setRequestMethod("POST");
httpUrlConnection.setRequestProperty("Connection", "Keep-Alive");
httpUrlConnection.setRequestProperty("Cache-Control", "no-cache");
httpUrlConnection.setRequestProperty("ENCTYPE", "multipart/form-data");
httpUrlConnection.setRequestProperty("Content-Type", "multipart/form-data;boundary=" + boundary);
DataOutputStream request = new DataOutputStream(httpUrlConnection.getOutputStream());
request.writeBytes(twoHyphens + boundary + crlf);
// Convert and add first image
ByteArrayOutputStream bao1 = new ByteArrayOutputStream();
params[0].compress(Bitmap.CompressFormat.JPEG, 100, bao1);
byte[] ba1 = bao1.toByteArray();
request.writeBytes("Content-Disposition: form-data; name=\"image1\";filename=\"image1\"" + crlf);
request.writeBytes(crlf);
request.write(ba1);
request.writeBytes(crlf);
request.writeBytes(twoHyphens + boundary + crlf);
// Convert and add second image
ByteArrayOutputStream bao2 = new ByteArrayOutputStream();
params[1].compress(Bitmap.CompressFormat.JPEG, 100, bao2);
byte[] ba2 = bao2.toByteArray();
request.writeBytes("Content-Disposition: form-data; name=\"image2\";filename=\"image2\"" + crlf);
request.writeBytes(crlf);
request.write(ba2);
request.writeBytes(crlf);
request.writeBytes(twoHyphens + boundary + crlf);
request.writeBytes("Content-Disposition: form-data; name=\"username\"" + crlf);
request.writeBytes(crlf);
request.writeBytes(username);
request.writeBytes(crlf);
request.writeBytes(twoHyphens + boundary + twoHyphens);
request.writeBytes("Content-Disposition: form-data; name=\"datestr\"" + crlf);
request.writeBytes(crlf);
request.writeBytes(timeStampString);
request.writeBytes(crlf);
request.writeBytes(twoHyphens + boundary + twoHyphens);
request.flush();
request.close();
int responseCode = httpUrlConnection.getResponseCode();
if (responseCode == HttpsURLConnection.HTTP_OK) {
InputStream responseStream = new BufferedInputStream(httpUrlConnection.getInputStream());
BufferedReader responseStreamReader = new BufferedReader(new InputStreamReader(responseStream, Charset.forName("UTF-8")));
String line;
while ((line = responseStreamReader.readLine()) != null) {
output = line;
Log.d(TAG, line);
}
responseStreamReader.close();
}
httpUrlConnection.disconnect();
if (output == "") {
httpResultsReturned = false;
} else {
httpResultsReturned = true;
}
} catch (ProtocolException e) {
e.printStackTrace();
return "failed";
} catch (MalformedURLException e) {
e.printStackTrace();
return "failed";
} catch (IOException e) {
e.printStackTrace();
return "failed";
}
On the server side I try to access the data as follows:
<?php
if($_SERVER['REQUEST_METHOD'] === 'POST'){
$image1 = $_FILES['image1']['name'];
$image2 = $_FILES['image2']['name'];
$datestr= $_POST['datestr'];
$username= $_POST['username'];
}
?>
Eventually, both images are successfully transmitted, however I cannot send/receive the extra parameters. I receive the responses correctly, but throughout all the php code (there are parts that I omitted in this question), it seems like none of the parameters are sent/received.
In this question, AndroSco shared the solution that worked for him, but in his php file it looks like he only accesses the image and not the parameter...
Since I don't have a lot of experience on this field, I believe that there is probably something very obvious that I do incorrectly/don't do at all!
Any suggestions will be appreciated!
Thanks!
After much frustration, I found the bug in my code. After having imported the two images in the transmitted message and when I wanted to import the other parameters, I wrote the boundary incorrectly. Instead of adding this:
request.writeBytes(twoHyphens + boundary + crlf);
having a new line at the end, I wrote this:
request.writeBytes(twoHyphens + boundary + twoHyphens);
adding two hyphens at the end of the line.
After replacing the twoHyphens with crlf, everything worked nicely!
I'm currently coding a Java Web Server. So far, it works to send htmt, css ... files but sending images does not work. After some research i found that you need to send the images binary data. The code for that http response:
response = "HTTP/1.1 200 \r\n";
response += "Server: Java Web Server/1.0 \r\n";
response += "Content-Type: image/png \r\n";
response += "Connection: close \r\n";
response += "Content-Length: " + f.length() + " \r\n";
response += "\r\n";
response += getBinaryCode(f);
getBinaryCode method:
private static String getBinaryCode(File f) {
BufferedImage image;
try {
image = ImageIO.read(f);
ByteArrayOutputStream b = new ByteArrayOutputStream();
ImageIO.write(image, "png", b);
byte[] jpgByteArray = b.toByteArray();
StringBuilder sb = new StringBuilder();
for (byte by : jpgByteArray)
sb.append(Integer.toBinaryString(by & 0xFF));
return sb.toString();
} catch (IOException e) {
e.printStackTrace();
}
return "";
}
The problem is that the image is not displayed in
the browser. Any ideas? Thanks in advance!
I am trying to do a simple servlet connection socket,
I am able to see this webpage and able to get to my servlet(on another eclipse instance) breakpoint when using a web browser.
but when i try to perform the following function:
public void Connect() {
try {
String params = URLEncoder.encode("ID", "UTF-8")
+ "=" + URLEncoder.encode("test", "UTF-8");
params += "&" + URLEncoder.encode("GOAL", "UTF-8")
+ "=" + URLEncoder.encode("Security", "UTF-8");
URL url = new URL(_address);
String host = url.getHost();
int port = url.getPort();
String path = url.getPath();
Socket socket = new Socket(host, port);
// Send headers
BufferedWriter wr = new BufferedWriter(new OutputStreamWriter(socket.getOutputStream(), "UTF8"));
wr.write("GET " + path + " HTTP/1.0\r\n");
wr.write("Content-Length: " + params.length() + "\r\n");
wr.write("Content-Type: application/x-www-form-urlencoded\r\n");
wr.write("\r\n");
// Send parameters
wr.write(params);
wr.flush();
// Get response
BufferedReader rd = new BufferedReader(new InputStreamReader(socket.getInputStream()));
String line;
String answer = "";
while ((line = rd.readLine()) != null) {
answer += line;
}
wr.close();
rd.close();
if (answer.indexOf(resourceStrings.ACCESS_GRANTED) != -1)
{
_result = true;
}
}
catch (Exception e) {
_result = false;
}
}
I just recieve the following answer:
HTTP/1.1 302 Found
Server: Apache-Coyote/1.1
Location: http://localhost:8180/Admin/
Date: Mon, 18 Apr 2016 15:00:28 GMT
Connection: close
without getting to my servlet code's breakpoint or retrieve any data from my "service" function in the servlet.
I am using Tomcat 7 if it makes any difference, do you have any idea what is causing this issue?
The parameters of a GET request are sent by appending them to the URL, not in the body of the request.
I've got a Node.js API that uses multer to handle multipart POST requests.
I am able to create a simple HTML form and POST images from there successfully.
I can also use postman to get the request to go through, but the req.file is always undefined on the server when I try to use my java method (below).
Called Method
public static void testPostImage() throws Exception {
String charset = "UTF-8";
String requestURL = "http://localhost:3000/accounts/2/details";
try {
File outputfile = new File(Util.getWorkingDirectory() + "/details");
MultipartUtility multipart = new MultipartUtility(requestURL, charset);
multipart.addFilePart("details", new File(outputfile.getAbsolutePath()));
List<String> response = multipart.finish();
General.println("SERVER REPLIED:");
for (String line : response) {
General.println(line);
}
} catch (IOException ex) {
General.println(ex);
}
}
The MultipartUtility class comes from this tutorial.
The contents of the constructor and 'addFilePart'...
Constructor
public MultipartUtility(String requestURL, String charset)
throws IOException {
this.charset = charset;
// creates a unique boundary based on time stamp
boundary = "===" + System.currentTimeMillis() + "===";
URL url = new URL(requestURL);
httpConn = (HttpURLConnection) url.openConnection();
httpConn.setUseCaches(false);
httpConn.setDoOutput(true); // indicates POST method
httpConn.setDoInput(true);
httpConn.setRequestProperty("Content-Type",
"multipart/form-data; boundary=" + boundary);
httpConn.setRequestProperty("User-Agent", "CodeJava Agent");
httpConn.setRequestProperty("Test", "Bonjour");
outputStream = httpConn.getOutputStream();
writer = new PrintWriter(new OutputStreamWriter(outputStream, charset),
true);
}
addFilePart
private static final String LINE_FEED = "\r\n";
public void addFilePart(String fieldName, File uploadFile)
throws IOException {
General.println("Sending to " + fieldName + ": " + uploadFile.getAbsolutePath());
// Add boundary
writer.append("--" + boundary).append(LINE_FEED);
// Add form data
writer.append("Content-Disposition: form-data;"
+ "name=\"myFile\";"
+ "filename=\"" + fieldName + "\""
+ "\nContent-Type: text/plain\n\n").append(LINE_FEED);
writer.append("Content-Type: " + "multipart/form-data").append(LINE_FEED);
writer.append("Content-Transfer-Encoding: binary").append(LINE_FEED);
writer.append(LINE_FEED);
writer.flush();
FileInputStream inputStream = new FileInputStream(uploadFile);
byte[] buffer = new byte[4096];
int bytesRead = -1;
while ((bytesRead = inputStream.read(buffer)) != -1) {
outputStream.write(buffer, 0, bytesRead);
}
outputStream.flush();
inputStream.close();
writer.append(LINE_FEED);
writer.flush();
}
Their might be more to it but you don't have the right line ending between your Content-disposition and Content-type header:
// Add form data
writer.append("Content-Disposition: form-data;"
+ "name=\"myFile\";"
+ "filename=\"" + fieldName + "\"").append(LINE_FEED);
writer.append("Content-Type: text/plain").append(LINE_FEED).append(LINE_FEED); // need 2 line feeds
Also you are mixing the order/type of headers
writer.append("Content-Type: " + "multipart/form-data").append(LINE_FEED);
writer.append("Content-Transfer-Encoding: binary").append(LINE_FEED);
Should come before your encoded data.
See examples here
I'm trying to build a small Java app for connecting to an application called CampFire and am running into trouble trying to upload files to the system. The Java code I'm using to upload a file is as follows:
public static String postFile(String requestUri, File f)
{
debug("Running postFile.");
logIn();
debug("Sending File: " + f.getAbsolutePath() + " to " + campFireURL + requestUri);
URL url;
URLConnection conn;
String linebreak = "\r\n";
String boundary = "**********xxx**********";
String twoHyphens = "--";
String result = "";
String request = twoHyphens + boundary + linebreak +
"Content-Disposition: form-data; name=\"upload\"; filename=\"" + f.getName() + "\"" + linebreak +
linebreak +
"";
debug("Request: " + request);
try
{
FileInputStream in = new FileInputStream(f);
auth.resetTries();
Authenticator.setDefault(auth);
// Send data
url = new URL(campFireURL + requestUri);
conn = url.openConnection();
conn.setDoOutput(true);
conn.setDoInput(true);
conn.setUseCaches(false);
conn.setRequestProperty("Connection", "Keep-Alive");
conn.setRequestProperty("Content-Type", "multipart/form-data; boundary=" + boundary);
DataOutputStream wr = new DataOutputStream(conn.getOutputStream());
wr.writeBytes(request);
int i;
while((i = in.read()) != -1)
{
wr.write(i);
}
wr.writeBytes(linebreak + twoHyphens + boundary + twoHyphens + linebreak);
wr.flush();
wr.close();
in.close();
result = readFromConnection(conn);
}
catch (Exception e)
{
debug(e);
JOptionPane.showMessageDialog(null, "Error running postData: " + e.getMessage(), "HTTP POST Error", JOptionPane.ERROR_MESSAGE);
die();
}
return(result);
}
When I run this with a real file though, I get the following errors...
Running postFile.
Sending File: /home/myuser/Desktop/blah.png to https://blah.campfirenow.com/room/blah/uploads.xml
Request: --**********xxx**********
Content-Disposition: form-data; name="upload"; filename="blah.png"
Server returned HTTP response code: 422 for URL: blah blah
java.io.IOException: Server returned HTTP response code: 422 for URL: blah blah
Any idea's what I'm doing wrong here? I'm fairly new at Java and am wondering if maybe I missed something obvious?
HTTP error 422 means "Unprocessable Entity". After a quick glance I can spot one mistake: a PNG file is a binary file. You've to add Content-Transfer-Encoding: binary to the header of the part.
If it still doesn't work, then you may find the example in the Uploading files section at the bottom of this answer useful.