Java function to vb.net

Question

User82651084 posted

I have been given a project where I must convert a java class into vb.net for itunes U, unfortunately I know c# and vb but not java. Here is what i have found online to so far:

/**
     * Send a request for an action to iTunes U with an authorization token.
     *
     * @param url URL defining how to communicate with iTunes U and 
     *          identifying which iTunes U action to invoke and which
     *          iTunes U page or item to apply the action to. Such URLs have
     *          a format like <CODE>[PREFIX]/[ACTION]/[DESTINATION]</CODE>,
     *          where <CODE>[PREFIX]</CODE> is a value like
     *          "https://deimos.apple.com/WebObjects/Core.woa" which defines
     *          how to communicate with iTunes U, <CODE>[ACTION]</CODE> is
     *          a value like "Browse" which identifies which iTunes U action
     *          to invoke, and <CODE>[DESTINATION]</CODE> is a value like
     *          "example.edu" which identifies which iTunes U page or item to
     *          apply the action to. The destination string "example.edu"
     *          refers to the root page of the iTunes U site identified by
     *          the domain "example.edu". Destination strings for other items
     *          within that site contain the site domain followed by
     *          numbers separated by periods. For example: 
     *          "example.edu.123.456.0789". You can find these strings in the
     *          items' URLs, which you can obtain from iTunes. See the
     *          iTunes U documentation for details.
     * @param token Authorization token generated by getAuthorizationToken().
     *
     * @return The iTunes U response, which may be HTML or
     *         text depending on the type of action invoked.
     */
    public String invokeAction(String url, String token) {

        // Send a request to iTunes U and record the response.
        StringBuffer response = null;
        try {

            // Verify that the communication will be over SSL.
            if (!url.startsWith("https")) {
                throw new MalformedURLException(
                    "ITunesU.invokeAction(): URL \""
                    + url + "\" does not use HTTPS.");
            }

            // Create a connection to the requested iTunes U URL.
            HttpURLConnection connection =
                    (HttpURLConnection)new URL(url).openConnection();
            connection.setUseCaches(false);
            connection.setDoOutput(true);
            connection.setRequestMethod("POST");
            connection.setRequestProperty(
                    "Content-Type",
                    "application/x-www-form-urlencoded; charset=UTF-8");
            // Send the authorization token to iTunes U.
            connection.connect();
            OutputStream output = connection.getOutputStream();
            output.write(token.getBytes("UTF-8"));
            output.flush();
            output.close();

            // Read iTunes U's response.
            response = new StringBuffer();
            InputStream input = connection.getInputStream();
            Reader reader = new InputStreamReader(input, "UTF-8");
            reader = new BufferedReader(reader);
            char[] buffer = new char[16 * 1024];
            for (int n = 0; n >= 0;) {
                n = reader.read(buffer, 0, buffer.length);
                if (n > 0) response.append(buffer, 0, n);
            }

            // Clean up.
            input.close();
            connection.disconnect();

        } catch (UnsupportedEncodingException e) {

            // ITunes U requires UTF-8 and ASCII encoding support.
            throw new java.lang.AssertionError(
                    "ITunesU.invokeAction(): UTF-8 encoding not supported!");

        } catch (IOException e) {

            // Report communication problems.
            throw new java.lang.AssertionError(
                    "ITunesU.invokeAction(): I/O Exception " + e);

        }

        // Return the response received from iTunes U.
        return response.toString();

    }

I have converted about half of this into a vb class but I can't find anything in .net that will work for HttpURLConnection connection = (HttpURLConnection)new URL(url).openConnection(); and 
throw new java.lang.AssertionError. Any help someone can give in converting this is greatly appreciated.

Answer 1

User-1659704165 posted

Hi,

have tried using

  HttpWebRequest,


http://msdn.microsoft.com/en-us/library/system.net.webrequest%28VS.71%29.aspx

Answer 2

User-952121411 posted

I have converted about half of this into a vb class but I can't find anything in .net that will work for HttpURLConnection connection = (HttpURLConnection)new URL(url).openConnection(); and

throw new java.lang.AssertionError. Any help someone can give in converting this is greatly appreciated.

 

The 'throw new...' code is just the developer throwing a custom exception message of type 'AssertionError'.  You need to do something similar with the equivalent or similar type exception in .NET.  Take a look to the following link that discusses the equivalent:

.Net equivalent to Java’s AssertionError:

http://stackoverflow.com/questions/1254044/net-equivalent-to-javas-assertionerror

As briefly eluded to in the previous post, take a look to the HttpRequest class in .NET.  Here are some better links (especially the 1st link) that will help get you started and mapping those settings from the JAVA code into the .NET Equivalent:

How to: Send Data Using the WebRequest Class:<!---->

http://msdn.microsoft.com/en-us/library/debx8sh9.aspx

HttpWebRequest Class:

<!---->

http://msdn.microsoft.com/en-us/library/system.net.httpwebrequest.aspx

 

Hope this helps!

Answer 3

User82651084 posted

I figured it out. I was making it harder than it actually was. Here is the code I used:

Public Shared Function ItunesU_login(ByVal nameString As String, ByVal emailString As String, ByVal usernameString As String, ByVal useridString As String) As String

        ' Credential string

        Dim credentialString As String = "Administrator@urn:mace:itunesu.com:sites:uic.edu"

        credentialString = "credentials=" & credentialString

        If nameString.Length > 0 Then

            nameString = "'" + nameString + "'"

        End If

        If emailString.Length > 0 Then

            emailString = "<" + emailString + ">"

        End If

        If usernameString.Length > 0 Then

            usernameString = "(" + usernameString + ")"

        End If

        If useridString.Length > 0 Then

            useridString = "[" + useridString + "]"

        End If

        Dim identityString As String = nameString + emailString + usernameString + useridString

        identityString = "identity=" + identityString

        ' Time string

        Dim epoch As New DateTime(1970, 1, 1, 0, 0, 0, _

        DateTimeKind.Utc)

        Dim now As DateTime = DateTime.UtcNow

        Dim interval As TimeSpan = now - epoch

        Dim seconds As Integer = CInt(interval.TotalSeconds)

        Dim timeString As String = "time=" & seconds

        ' Token string (so far)

        Dim tokenString As String = ((credentialString & " & ") + identityString & " & ") + timeString

        tokenString = tokenString.Replace(" ", "+")

        tokenString = tokenString.Replace("'", "%23")

        tokenString = tokenString.Replace("(", "%28")

        tokenString = tokenString.Replace(")", "%29")

        tokenString = tokenString.Replace(":", "%3A")

        tokenString = tokenString.Replace("<", "%3C")

        tokenString = tokenString.Replace(">", "%3E")

        tokenString = tokenString.Replace("@", "%40")

        tokenString = tokenString.Replace("[", "%5B")

        tokenString = tokenString.Replace("]", "%5D")

        'Compute signature string

        Dim sharedSecret As String = "SHAREDSECRETWITH32CHARACTERSSINIT"

        Dim encodedKey As Byte() = System.Text.Encoding.UTF8.GetBytes(sharedSecret)

        Dim hmac As System.Security.Cryptography.HMACSHA256 = New System.Security.Cryptography.HMACSHA256(encodedKey)

        Dim digest As Byte() = hmac.ComputeHash(System.Text.Encoding.UTF8.GetBytes(tokenString))

        Dim digestString As String = ToHexString(digest)

        digestString = digestString.ToLower(System.Globalization.CultureInfo.InvariantCulture)

        Dim signatureString = "signature=" + digestString

        ' Token string (final)

        tokenString = (tokenString & " & ") + signatureString

        Dim iTunesURLString As String = ("https://deimos.apple.com/WebObjects/Core.woa/Browse/uic.edu" & "?") + tokenString

        Return iTunesURLString

    End Function

    Public Shared Function ToHexString(ByVal bytes As Byte()) As String

        Dim hexString As String = ""

        For i As Integer = 0 To bytes.Length - 1

            Dim num As Integer = bytes(i)

            hexString += [String].Format("{0:X2}", num)

        Next

        Return hexString

    End Function

        ' Credential string

        Dim credentialString As String = "Administrator@urn:mace:itunesu.com:sites:uic.edu"

        credentialString = "credentials=" & credentialString

        If nameString.Length > 0 Then

            nameString = "'" + nameString + "'"

        End If

        If emailString.Length > 0 Then

            emailString = "<" + emailString + ">"

        End If

        If usernameString.Length > 0 Then

            usernameString = "(" + usernameString + ")"

        End If

        If useridString.Length > 0 Then

            useridString = "[" + useridString + "]"

        End If

        Dim identityString As String = nameString + emailString + usernameString + useridString

        identityString = "identity=" + identityString

        ' Time string

        Dim epoch As New DateTime(1970, 1, 1, 0, 0, 0, _

        DateTimeKind.Utc)

        Dim now As DateTime = DateTime.UtcNow

        Dim interval As TimeSpan = now - epoch

        Dim seconds As Integer = CInt(interval.TotalSeconds)

        Dim timeString As String = "time=" & seconds

        ' Token string (so far)

        Dim tokenString As String = ((credentialString & " & ") + identityString & " & ") + timeString

        tokenString = tokenString.Replace(" ", "+")

        tokenString = tokenString.Replace("'", "%23")

        tokenString = tokenString.Replace("(", "%28")

        tokenString = tokenString.Replace(")", "%29")

        tokenString = tokenString.Replace(":", "%3A")

        tokenString = tokenString.Replace("<", "%3C")

        tokenString = tokenString.Replace(">", "%3E")

        tokenString = tokenString.Replace("@", "%40")

        tokenString = tokenString.Replace("[", "%5B")

        tokenString = tokenString.Replace("]", "%5D")

        'Compute signature string

        Dim sharedSecret As String = "SHAREDSECRETWITH32CHARACTERSSINIT"

        Dim encodedKey As Byte() = System.Text.Encoding.UTF8.GetBytes(sharedSecret)

        Dim hmac As System.Security.Cryptography.HMACSHA256 = New System.Security.Cryptography.HMACSHA256(encodedKey)

        Dim digest As Byte() = hmac.ComputeHash(System.Text.Encoding.UTF8.GetBytes(tokenString))

        Dim digestString As String = ToHexString(digest)

        digestString = digestString.ToLower(System.Globalization.CultureInfo.InvariantCulture)

        Dim signatureString = "signature=" + digestString

        ' Token string (final)

        tokenString = (tokenString & " & ") + signatureString

        Dim iTunesURLString As String = ("https://deimos.apple.com/WebObjects/Core.woa/Browse/uic.edu" & "?") + tokenString

        Return iTunesURLString

    End Function

    Public Shared Function ToHexString(ByVal bytes As Byte()) As String

        Dim hexString As String = ""

        For i As Integer = 0 To bytes.Length - 1

            Dim num As Integer = bytes(i)

            hexString += [String].Format("{0:X2}", num)

        Next

        Return hexString

    End FunctionPublic Shared Function ItunesU_login(ByVal nameString As String, ByVal emailString As String, ByVal usernameString As String, ByVal useridString As String) As String

        ' Credential string

        Dim credentialString As String = "Administrator@urn:mace:itunesu.com:sites:uic.edu"

        credentialString = "credentials=" & credentialString

        If nameString.Length > 0 Then

            nameString = "'" + nameString + "'"

        End If

        If emailString.Length > 0 Then

            emailString = "<" + emailString + ">"

        End If

        If usernameString.Length > 0 Then

            usernameString = "(" + usernameString + ")"

        End If

        If useridString.Length > 0 Then

            useridString = "[" + useridString + "]"

        End If

        Dim identityString As String = nameString + emailString + usernameString + useridString

        identityString = "identity=" + identityString

        ' Time string

        Dim epoch As New DateTime(1970, 1, 1, 0, 0, 0, _

        DateTimeKind.Utc)

        Dim now As DateTime = DateTime.UtcNow

        Dim interval As TimeSpan = now - epoch

        Dim seconds As Integer = CInt(interval.TotalSeconds)

        Dim timeString As String = "time=" & seconds

        ' Token string (so far)

        Dim tokenString As String = ((credentialString & " & ") + identityString & " & ") + timeString

        tokenString = tokenString.Replace(" ", "+")

        tokenString = tokenString.Replace("'", "%23")

        tokenString = tokenString.Replace("(", "%28")

        tokenString = tokenString.Replace(")", "%29")

        tokenString = tokenString.Replace(":", "%3A")

        tokenString = tokenString.Replace("<", "%3C")

        tokenString = tokenString.Replace(">", "%3E")

        tokenString = tokenString.Replace("@", "%40")

        tokenString = tokenString.Replace("[", "%5B")

        tokenString = tokenString.Replace("]", "%5D")

        'Compute signature string

        Dim sharedSecret As String = "SHAREDSECRETWITH32CHARACTERSSINIT"

        Dim encodedKey As Byte() = System.Text.Encoding.UTF8.GetBytes(sharedSecret)

        Dim hmac As System.Security.Cryptography.HMACSHA256 = New System.Security.Cryptography.HMACSHA256(encodedKey)

        Dim digest As Byte() = hmac.ComputeHash(System.Text.Encoding.UTF8.GetBytes(tokenString))

        Dim digestString As String = ToHexString(digest)

        digestString = digestString.ToLower(System.Globalization.CultureInfo.InvariantCulture)

        Dim signatureString = "signature=" + digestString

        ' Token string (final)

        tokenString = (tokenString & " & ") + signatureString

        Dim iTunesURLString As String = ("https://deimos.apple.com/WebObjects/Core.woa/Browse/uic.edu" & "?") + tokenString

        Return iTunesURLString

    End Function

    Public Shared Function ToHexString(ByVal bytes As Byte()) As String

        Dim hexString As String = ""

        For i As Integer = 0 To bytes.Length - 1

            Dim num As Integer = bytes(i)

            hexString += [String].Format("{0:X2}", num)

        Next

        Return hexString

    End Function