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Posting minutiae byte array from applet to server - java

In Grails web application, I am trying to post minutiae (finger print) byte array from applet to server using rest API.
This what i tried so for
private String post(String purl,String customerId, byte[] regMin1,byte[] regMin2) throws Exception {
StringBuilder parameters = new StringBuilder();
parameters.append("customerId=");
parameters.append(customerId);
parameters.append("&regMin1=");
parameters.append(URLEncoder.encode(new String(regMin1),"UTF-8"));
parameters.append("&regMin2=");
parameters.append(URLEncoder.encode(new String(regMin2),"UTF-8"));
URL url = new URL(purl);
HttpURLConnection connection = (HttpURLConnection) url.openConnection();
connection.setDoOutput(true);
connection.setDoInput(true);
connection.setRequestMethod("POST");
connection.setRequestProperty("Content-Type", "application/x-www-form-urlencoded");
connection.setRequestProperty("Content-Length",Integer.toString(parameters.toString().getBytes().length));
DataOutputStream wr = new DataOutputStream(connection.getOutputStream ());
wr.writeBytes(parameters.toString());
wr.flush();
wr.close();
BufferedReader in = new BufferedReader(new InputStreamReader(
connection.getInputStream()));
StringBuilder builder = new StringBuilder();
String aux = "";
while ((aux = in.readLine()) != null) {
builder.append(aux);
}
in.close();
connection.disconnect();
return builder.toString();
}
I can post regMin1, regMin2 successfully but fingerprint verification always failing. I doubt, am i posting correctly.

This looks like a very bad idea to me:
parameters.append(URLEncoder.encode(new String(regMin1),"UTF-8"));
...
parameters.append(URLEncoder.encode(new String(regMin2),"UTF-8"));
If regMin1 and regMin2 aren't actually UTF-8 text (and my guess is that they're not) you'll almost certainly be losing data here.
Don't treat arbitrary binary data as if it's encoded text.
Instead, convert regMin1 and regMin2 to base64 - that way you'll end up with ASCII characters which you can then decode on the server to definitely get the original binary data. You can use a URL-safe version of base64 to avoid having to worry about further encoding the result.
There's a good public domain base64 library you can use for this if you don't have anything else to hand. So for example:
parameters.append("&regMin1=")
.append(Base64.encodeBytes(regMin1, Base64.URL_SAFE))
.append("&regMin2=")
.append(Base64.encodeBytes(regMin2, Base64.URL_SAFE));
Note that you'd want to decode with the URL_SAFE option as well - don't just try to decode it as "normal" base64 data.
(You might still want to convert this to a POST request, and you'd definitely have an easier time if you could use a better HTTP library, but they're slightly separate concerns.)

Related

I want to commit text file "demo2.txt" to bitbucket server using rest API. I can upload the same file using Postman but it's not working with Java code. As shown in the below code I want to send string object "str" as the body. Can someone help me here to upload the file on the bitbucket server? Also Please let me know if there is any other way to do this.
URL url = new URL("https://api.bitbucket.org/2.0/repositories/{team name}/{repository name}/src");
HttpURLConnection httpCon = (HttpURLConnection) url.openConnection();
httpCon.setRequestProperty("X-Requested-with", "Curl");
httpCon.setDoOutput(true);
httpCon.setDoInput(true);
httpCon.setRequestProperty("Connection", "Keep-Alive");
httpCon.setRequestProperty("Content-Type", "multipart/form-data; boundary="+boundary);
httpCon.setRequestProperty("Accept", "application/x-www-form-urlencoded");
httpCon.setRequestProperty("Authorization", basicauth);
httpCon.setRequestMethod("POST");
String str =
"{"
+ "\"-F\":\"File3=#/D:/log/demo2.txt\" "
+ "}";
try {
OutputStream output = httpCon.getOutputStream();
output.write(str.getBytes());
output.close();
} catch(Exception e){
System.out.println(e.getMessage());
}
int responseCode = httpCon.getResponseCode();
String inputLine;
StringBuffer response = new StringBuffer();
if (responseCode == HttpURLConnection.HTTP_OK || responseCode == HttpURLConnection.HTTP_CREATED){
BufferedReader in = new BufferedReader(new .
InputStreamReader(httpCon.getInputStream()));
while ((inputLine = in.readLine()) != null) {
response.append(inputLine);
}
in.close();
List<String> message = new ArrayList<>();
message.add(response.toString());
}

If this is all of your code, then your problem may be as simple as the fact that you're not making any sort of call to finalize the request...to tell HttpURLConnection that you're done forming the request and want it to complete. There are two things you can do to help this:
close the output stream when you're done writing to it. You're generally supposed to do this. Here, you can call output.close(). Better still, since you have a try/catch block already anyway, use a "try with resources" construct to make sure that the stream is closed no matter what happens (assuming you're using a newer version of Java that supports this).
make some sort of call to query the response to the request. It may
be that the request is not being fully sent until you do this. Try
calling httpCon.getResponseCode() at the bottom of your code.
Given that you have provided no information as to what "it's not working with Java code" means, this may be useful information but not the ultimate solution to your problem. Your code does look good other than exhibiting these omissions.

This question already has answers here:
Why does LogCat not show the full message?
(2 answers)
Closed 8 years ago.
I work with HttpUrlConnection in my App and in my common Java Test and I implemented a method and that Method (common for both of them, so, identical!!!) behaves in Android case in another way.
Both of them can right receive an identical response from Server but in Java Test I can show this response while in Android App is chunked to 3200 Chars.
That's my Code
private String sendPost() throws Exception{
String url = "http://www.something.com/my_page.jsp?";
URL obj = new URL(url);
HttpURLConnection con = (HttpURLConnection) obj.openConnection();
//add request header
con.setRequestMethod("POST");
String urlParameters ="param1=val1&param2=val2";
// Send post request
con.setDoOutput(true);
DataOutputStream wr = new DataOutputStream(con.getOutputStream());
wr.writeBytes(urlParameters);
wr.flush();
wr.close();
BufferedReader in = new BufferedReader(new InputStreamReader(con.getInputStream()));
String inputLine;
response = new StringBuffer();
while ((inputLine = in.readLine()) != null) {
response.append(inputLine);
}
in.close();
// return result
Log.i("TAG", "sendPost:: Response length : " + response.length()); // <- This line returns the same length!!!
return response.toString();
}
All I can get of this object con from Class HttpUrlConnection like ContentLength, ContentType, etc is the same in both of these cases, therefore I suspect, there must be an intern Setting/Parameter of String/StringBuffer in Android, which distinguishes these case but I don't know what. readLine reads the same or at least the same number of chars cause the length of response is the same in both of cases.
If you could say me, what is wrong, I'd be very thankful.
Kind Regards

I can't understand your description of the symptoms; i.e. why you think that something is being truncated.
However, I can assure you that it is NOT due to a limit on the length of String or StringBuffer.
Those two classes do have a limit, but it is 2**31 (i.e. >2 billion) characters. You will typically get an OutOfMemoryError before your buffer gets that big.

I'm writing a small crawler for sites in English only, and doing that by opening a URL connection. I set the encoding to utf-8 both on the request, and the InputStreamReader but I continue to get gobbledigook for some of the requests, while others work fine.
The following code represents all the research I did and advice out there. I have also tried changing URLConnection to HttpURLConnection with no luck. Some of the returned strings continue to look like this:
??}?r?H????P?n?c??]?d?G?o??Xj{?x?"P$a?Qt?#&??e?a#?????lfVx)?='b?"Y(defUeefee=??????.??a8??{O??????zY?2?M???3c??#
What am I missing?
My code:
public static String getDocumentFromUrl(String urlString) throws Exception {
String wholeDocument = null;
URL url = new URL(urlString);
URLConnection conn = url.openConnection();
conn.setRequestProperty("Content-Type", "text/plain; charset=utf-8");
conn.setRequestProperty("Accept-Charset", "utf-8");
conn.setConnectTimeout(60*1000); // wait only 60 seconds for a response
conn.setReadTimeout(60*1000);
InputStreamReader isr = new InputStreamReader(conn.getInputStream(), "utf-8");
BufferedReader in = new BufferedReader(isr);
String inputLine;
while ((inputLine = in.readLine()) != null) {
wholeDocument += inputLine;
}
isr.close();
in.close();
return wholeDocument;
}

The server is sending the document GZIP compressed. You can set the Accept-Encoding HTTP header to make it send the document in plain text.
conn.setRequestProperty("Accept-Encoding", "identity");
Even so, the HTTP client class handles GZIP compression for you, so you shouldn't have to worry about details like this. What seems to be going on here is that the server is buggy: it does not send the Content-Encoding header to tell you the content is compressed. This behavior seems to depend on the User-Agent, so that the site works in regular web browsers but breaks when used from Java. So, setting the user agent also fixes the issue:
conn.setRequestProperty("User-Agent", "Mozilla/5.0"); // for example

I am currently working with android and i am using a http connection with some headers (i havent included them or the real url for security purposes) to get a JSON response from an API, and feeding that response back into the application. The problem that i am having is that when using the getContentLength method of the http request, the wrong length is being returned (wrong length returned is 1225, the correct length in characters of the JSON array is 3365).
I have a feeling that the JSON is not fully loaded when my reader starts to read it, and as such is only reading the loaded JSON at that point. Is there any way around this, possibly using a delay on the HTTP connection or waiting until it is fully loaded to read the data?
URL url = new URL("https://www.exampleofurl.com");
HttpURLConnection request = (HttpURLConnection) url.openConnection();
request.connect();
int responseCode = request.getResponseCode();
if(responseCode == HttpURLConnection.HTTP_OK) {
InputStream inputStream = request.getInputStream();
InputStreamReader reader = new InputStreamReader(inputStream);
long contentLength2 = Long.parseLong(request.getHeaderField("Content-Length"));
Log.i("contentLength: ", "Content: " + contentLength2);

I generally don't recommend always relying on "Content-Length" as it may not be available (you get -1), or perhaps affected by intermediate proxy.
Why don't you just read your stream until it is exhausted into memory buffer (say, StringBuilder) and then get the actual size, for example :
BufferedReader br = new BufferedReader(inputStream); // inputStream in your code
String line;
StringBuilder sb = new StringBuilder();
while ((line = br.readLine()) != null) {
sb.append(line);
}
// finished reading
System.out.println("data size = " + sb.length());
JSONObject data = new JSONObject(sb.toString());
// and don't forget finally clauses with closing streams/connections

I want to post among other data a String variable to a PHP file by using the HttpConnection stuff. The first data is the byte[] data returned from a recordstore. So it should be posted alone. So how to post the String variable also ?

You can pass the data to a PHP file using GET or POST methods.
Get method is the easy way to pass simple data. Using GET you can add the variable to the URL
Example:
192.168.1.123/myproject/uploads/treatphoto.php?myVariable1=MyContent&myVariable2=MyContent2
And in PHP:
$content1 = $_GET['myVariable1'];
$content2 = $_GET['myVariable2'];
Also the content of "MyContent" needs to be an string encoded. using any UrlEncoder.
To pass a byte[] array using this method you need to convert the byte array to an string encoded in some printable encoding like base64
The GET method also has a sort limit of data that can be passed safely (usually 2048 bytes)
The other method "POST" is more complex (but not a lot), way to add more data.
You need to prepare the HttpConnection to pass the data as POST.
Also the data stored in urlParamenters need to be according to the url enconding.
Passing the data using post is similar to GET but instead of adding all the variables next to the url the varuiables are added in the Stream of the httpConnection request.
example of the java code:
String urlParameters = "myVariable1=myValue1&myVariable2=myValue2";
HttpURLConnection connection = null;
try {
url = new URL(targetURL);
connection = (HttpURLConnection)url.openConnection();
// Use post and add the type of post data as URLENCODED
connection.setRequestMethod("POST");
connection.setRequestProperty("Content-Type","application/x-www-form-urlencoded");
// Optinally add the language and the data content
connection.setRequestProperty("Content-Length", "" + Integer.toString(urlParameters.getBytes().length));
connection.setRequestProperty("Content-Language", "en-US");
// Set the mode as output and disable cache.
connection.setUseCaches (false);
connection.setDoInput(true);
connection.setDoOutput(true);
//Send request
DataOutputStream wr = new DataOutputStream (connection.getOutputStream ());
wr.writeBytes (urlParameters);
wr.flush ();
wr.close ();
// Get Response
// Optionally you can get the response of php call.
InputStream is = connection.getInputStream();
BufferedReader rd = new BufferedReader(new InputStreamReader(is));
String line;
StringBuffer response = new StringBuffer();
while((line = rd.readLine()) != null) {
response.append(line);
response.append('\r');
}
rd.close();
return response.toString();
The php is similar, you only need to replace $_GET by $_POST:
$content1 = $_POST['myVariable1'];
$content2 = $_POST['myVariable2'];