CODEWITHSUNDEEP
c#javabase64fileinputstream
sara brown
sara brown

Reputation: 1077

get the video file after convert from base64 and UTF8 in c#

what i need to do is sending a file from java to c#. the java act as the client meanwhile, c# act as server.

the file is loaded in java through fileinputstream and its been converted to utf8 then base64. see the code.

FileInputStream fin=new FileInputStream(fileName);
          byte[] content = new byte[fin.available()];
          fin.read(content, 0, content.length);
          String asString = new String(content, "UTF8");
          byte[] newBytes = asString.getBytes("UTF8");
          String base64 = Base64.encodeToString(newBytes, Base64.DEFAULT);

and the server (using c# language) will read the data send and convert it back as a file. im using base64 then to utf8 and last i am not sure how to make it. what im trying to send is video.mp4 size of 144kb or less. so far, the output shows the catch of "WRONG FORMAT". see the code.

    try
            {

                for (int i = 0; i <= _server.Q.NoOfItem - 1; i++)
                {
                    words = _server.Q.ElementAtBuffer(i).ToString();
                    //textBox1.Text = words;


                    byte[] encodedDataAsBytes = System.Convert.FromBase64String(words);
                    string returnValue = System.Text.Encoding.UTF8.GetString(encodedDataAsBytes);

                    textBox1.Text = returnValue;

                }
}
            catch (ArgumentNullException argNull) 
            {
                textBox1.Text = "Received null value";
            }
            catch (FormatException FrmtEx)
            {
                textBox1.Text = "Wrong format";
            }

you can ignore the for (int i = 0; i <= _server.Q.NoOfItem - 1; i++) as this is the way i want to capture/retrieve the data sent.

p/s: it works when im just trying to pass any string without load the file (string >> utf8 >> base64) and to receive (base64 >> utf8 >> string).

Upvotes: 0

Views: 2407

Answers (2)

Jon Skeet
Jon Skeet

Reputation: 1502825

the file is loaded in java through fileinputstream and its been converted to utf8

Then you've lost data. Video data is not text data, so don't load it as text data. Treat it as binary data - by all means encode it to base64 if you need to represent it as a string somewhere but don't perform any text decoding on it, as that's only meant for encoded text data, which this isn't.

It's really important to understand what's wrong here. The only thing the two lines below can do is lose data. If they don't lose data, they serve no purpose - and if they do lose data, they're clearly a bad idea:

String asString = new String(content, "UTF8");
byte[] newBytes = asString.getBytes("UTF8");

You should analyze how you ended up with this code in the first place... why did you feel the need to convert the byte array to a string and back?

jowierun's answer is also correct - you shouldn't be using available() at all. You might want to use utility methods from Guava, such as Files.toByteArray if you definitely need to read the whole file into memory in one go.

p/s: it works when im just trying to pass any string without load the file (string >> utf8 >> base64) and to receive (base64 >> utf8 >> string).

Well yes - if you start with text data, then that's fine - UTF-8 can represent every valid string, and base64 is lossless, so you're fine. (Admittedly you could break it by presenting an invalid string with half of a surrogate pair, but...) The problem is at the point where you treat non-text data as text in the first place.

Upvotes: 2

Paul Jowett
Paul Jowett

Reputation: 6581

You shouldn't use fin.available() to assume you can read the file in one go. That is likely to work for only small files. Instead you need to do the read in a loop and collect all the contents together before you encode it.

It would make sense to (on the java side at least) to have a decode that routine you can use to TEST that your encode is working (a unit test perhaps?). You will probably find that test is failing consistently with the problem you are getting.

Upvotes: 0

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