Develop Reference

Reading String from TwinCAT PLC using ADS.NET returns ???? after data

I'm trying to read String data from TwinCAT PLC using WinForm and ADS.NET. I based my code from their sample codes.
Writing the string into the console shows my data as: "123456????????????????????????".
I can use a textbox and it will show and save "123456" but I want to save it directly without using textboxes.
What am I doing wrong? Or is there something missing from my code?
Thanks!
Additional info:
(I'm trying to save the data into a DB):
Code:
private String readPLCData(String variableHandle)
{
int length;
string text;
AdsStream dataStream;
BinaryReader reader;
try
{
varHandle = adsClient.CreateVariableHandle(variableHandle);
// length of the stream = length of string in sps + 1
dataStream = new AdsStream(31);
reader = new BinaryReader(dataStream, System.Text.Encoding.ASCII);
length = adsClient.Read(varHandle, dataStream);
text = new string(reader.ReadChars(length));
return text;
}
catch (Exception err)
{
MessageBox.Show(err.Message);
return null;
}
}

Saving an image from bytes

I am trying to create an API which will save an image at a given location .
Below is my Code for that
Image image = Image.FromFile(#"C:\Users\abc\Desktop\img-logo.jpg");
byte[] bytes = (byte[])(new ImageConverter()).ConvertTo(image, typeof(byte[]));
string str = Convert.ToBase64String(bytes);
Save_Application_Image("12004", str);
and the method in API
public void Save_Application_Image(string staffCode , string bytearray)
{
try
{
byte[] bytes = Convert.FromBase64String(bytearray);
file_path = "~/uploads/" + file_name;
FileStream file = File.Create(HttpContext.Current.Server.MapPath(file_path));
file.Write(bytes, 0, bytes.Length);
file.Close();
}
catch(Exception ex)
{
logger.LogError(ex);
}
finally
{
}
}
This api has to be called from Android Application so I will receive two string parameter.
It is saving the file perfectly but file is not readable. No preview for image file.
What is the right approach for this ?

I'm unsure of how the ImageConverter works, but I've used this before to convert Images to byte[]:
Image image = Image.FromFile(#"C:\Users\abc\Desktop\img-logo.jpg");
using (var stream = new MemoryStream())
{
image.Save(stream);
string savedImage = Convert.ToBase64String(stream.ToArray());
Save_Application_Image("12004", str);
}

C# - Having problems with processing a Stream more than once

I have a android mobile application that has functionality to set a profile picture.
I send a variable containing the path of the image to a method that does the following:
string imagePath = _ProfilePicture.GetTag (Resource.String.profile_picture_path).ToString ();
byte[] imageBytes = System.IO.File.ReadAllBytes(imagePath);
Stream imageStream = new MemoryStream(imageBytes);
After this block of code I send the imageStream variable to UploadUserProfilePicture(imageStream); which is located on the WCF Service
Currently it only sends the stream, but because we cannot send another parameter containing the extension. We save all images as png. I have however found a library that requires the stream to be parsed to bytes and then based on the bytes the file type can retrieved.
However when I then try to use the same stream to Write the file to the location on the server, the position is at the end so the file created is always 0 bytes.
I have tried:
Doing the conversion to Bytes in another method and only returning the fileType, however the originals position was still at the end.
The CopyTo function gave me the same results.
I tried using the Seek function and setting it's position back to zero however the I get a NotSupportedException.
I tried this as well:
string content;
var reader = new StreamReader(image);
content = reader.ReadToEnd();
image.Dispose();
image = new MemoryStream(Encoding.UTF8.GetBytes(content));
^ this seems to corrupt the stream as I cannot get the FileType nor write it to the above location.
I have also had a look at: How to read a Stream and reset its position to zero even if stream.CanSeek == false
This is the method on the WCF Service:
public Result UploadUserProfilePicture(Stream image)
{
try
{
FileType fileType = CommonMethods.ReadToEnd(image).GetFileType();
Guid guid = Guid.NewGuid();
string imageName = guid.ToString() + "." + fileType.Extension;
var buf = new byte[1024];
var path = Path.Combine(#"C:\" + imageName);
int len = 0;
using (var fs = File.Create(path))
{
while ((len = image.Read(buf, 0, buf.Length)) > 0)
{
fs.Write(buf, 0, len);
}
}
return new Result
{
Success = true,
Message = imageName
};
}
catch(Exception ex)
{
return new Result
{
Success = false,
Message = ex.ToString()
};
}
Link to Library Used: https://github.com/Muraad/Mime-Detective
The CommonMethods.ReadToEnd(image) method can be found here: How to convert an Stream into a byte[] in C#? as the questions answer
I hope this is enough information on my problem.

On the server side, you receive a stream from WCF that does not support seek operations. You can, however, read the stream to memory as the GetFileType method requires an array of bytes as input parameter. Instead of accessing the original stream again, you can write the bytes of the array to disk in a very easy way using the File.WriteAllBytes method:
public Result UploadUserProfilePicture(Stream image)
{
try
{
// Store bytes in a variable
var bytes = CommonMethods.ReadToEnd(image);
FileType fileType = bytes.GetFileType();
Guid guid = Guid.NewGuid();
string imageName = guid.ToString() + "." + fileType.Extension;
var path = Path.Combine(#"C:\" + imageName);
File.WriteAllBytes(path, bytes);
return new Result
{
Success = true,
Message = imageName
};
}
catch(Exception ex)
{
return new Result
{
Success = false,
Message = ex.ToString()
};
}
}
Please note that this means that you store a possibly large amount of bytes in memory, in the same way you already did before. It would be better if you could use the stream without reading all bytes into memory, so looking for an alternative for the GetFileType method that can handle a stream is well worth the time. You could then first save the image to a temporary file and then open a new FileStream to discover the correct file type so that you can rename the file.

Converting byte array to image

We are using Flash to send an image to the servers and upload an image. The way we're trying to do this is by sending the bytes to the server through a parameter and then converting the bytes to an image.
http://i.gyazo.com/fb8225af80ef465b0262d97f63bd54b2.png
In the image the object is sending a few different bits of information. I'm not sure if I am supposed to just receive one bit of information instead of the entire object.
So far I have the post request
string byteArray = Request["bytes"];
Then I am trying to convert it to an image
string file_name = Guid.NewGuid().ToString();
//byte[] imageBytes = Convert.FromBase64String(byteArray);
Derio.App.Model.Helper.ByteArrayToFile(file_name, Derio.App.Model.Helper.GetBytes(byteArray));
My helper method looks like -
public static class Helper
{
public static byte[] GetBytes(string str)
{
byte[] bytes = new byte[str.Length * sizeof(char)];
System.Buffer.BlockCopy(str.ToCharArray(), 0, bytes, 0, bytes.Length);
return bytes;
}
public static string ByteArrayToFile(string _FileName, byte[] _ByteArray)
{
try
{
// Open file for reading
System.IO.FileStream _FileStream =
new System.IO.FileStream(_FileName, System.IO.FileMode.Create,
System.IO.FileAccess.Write);
// Writes a block of bytes to this stream using data from
// a byte array.
_FileStream.Write(_ByteArray, 0, _ByteArray.Length);
// close file stream
_FileStream.Close();
return "true";
}
catch (Exception _Exception)
{
// Error
return "Exception caught in process:" + _Exception.ToString();
}
}
}
We've multiple different methods such as trying to convert it from Base64String to an image.
I can't for the life of me though figure out what I am doing wrong.

What happens when you try this:
string file_name = Guid.NewGuid().ToString();
string byteArray = Request["bytes"];
byte[] imageBytes = Convert.FromBase64String(byteArray);
IO.File.WriteAllBytes(file_name, imageBytes);

Converting file into Base64String and back again

The title says it all:
I read in a tar.gz archive like so
break the file into an array of bytes
Convert those bytes into a Base64 string
Convert that Base64 string back into an array of bytes
Write those bytes back into a new tar.gz file
I can confirm that both files are the same size (the below method returns true) but I can no longer extract the copy version.
Am I missing something?
Boolean MyMethod(){
using (StreamReader sr = new StreamReader("C:\...\file.tar.gz")) {
String AsString = sr.ReadToEnd();
byte[] AsBytes = new byte[AsString.Length];
Buffer.BlockCopy(AsString.ToCharArray(), 0, AsBytes, 0, AsBytes.Length);
String AsBase64String = Convert.ToBase64String(AsBytes);
byte[] tempBytes = Convert.FromBase64String(AsBase64String);
File.WriteAllBytes(#"C:\...\file_copy.tar.gz", tempBytes);
}
FileInfo orig = new FileInfo("C:\...\file.tar.gz");
FileInfo copy = new FileInfo("C:\...\file_copy.tar.gz");
// Confirm that both original and copy file have the same number of bytes
return (orig.Length) == (copy.Length);
}
EDIT: The working example is much simpler (Thanks to #T.S.):
Boolean MyMethod(){
byte[] AsBytes = File.ReadAllBytes(#"C:\...\file.tar.gz");
String AsBase64String = Convert.ToBase64String(AsBytes);
byte[] tempBytes = Convert.FromBase64String(AsBase64String);
File.WriteAllBytes(#"C:\...\file_copy.tar.gz", tempBytes);
FileInfo orig = new FileInfo(#"C:\...\file.tar.gz");
FileInfo copy = new FileInfo(#"C:\...\file_copy.tar.gz");
// Confirm that both original and copy file have the same number of bytes
return (orig.Length) == (copy.Length);
}
Thanks!

If you want for some reason to convert your file to base-64 string. Like if you want to pass it via internet, etc... you can do this
Byte[] bytes = File.ReadAllBytes("path");
String file = Convert.ToBase64String(bytes);
And correspondingly, read back to file:
Byte[] bytes = Convert.FromBase64String(b64Str);
File.WriteAllBytes(path, bytes);

Another working example in VB.NET:
Public Function base64Encode(ByVal myDataToEncode As String) As String
Try
Dim myEncodeData_byte As Byte() = New Byte(myDataToEncode.Length - 1) {}
myEncodeData_byte = System.Text.Encoding.UTF8.GetBytes(myDataToEncode)
Dim myEncodedData As String = Convert.ToBase64String(myEncodeData_byte)
Return myEncodedData
Catch ex As Exception
Throw (New Exception("Error in base64Encode" & ex.Message))
End Try
'
End Function

private String encodeFileToBase64Binary(File file){
String encodedfile = null;
try {
FileInputStream fileInputStreamReader = new FileInputStream(file);
byte[] bytes = new byte[(int)file.length()];
fileInputStreamReader.read(bytes);
encodedfile = Base64.encodeBase64(bytes).toString();
} catch (FileNotFoundException e) {
// TODO Auto-generated catch block
e.printStackTrace();
} catch (IOException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
return encodedfile;
}

For Java, consider using Apache Commons FileUtils:
/**
* Convert a file to base64 string representation
*/
public String fileToBase64(File file) throws IOException {
final byte[] bytes = FileUtils.readFileToByteArray(file);
return Base64.getEncoder().encodeToString(bytes);
}
/**
* Convert base64 string representation to a file
*/
public void base64ToFile(String base64String, String filePath) throws IOException {
byte[] bytes = Base64.getDecoder().decode(base64String);
FileUtils.writeByteArrayToFile(new File(filePath), bytes);
}