If I have image data in an NSData, extracted from the image as follows, how do I convert this NSData object into a byte array?
NSData data = NSData.FromUrl(NSUrl.FromString(urlString));
NSData data = NSData.FromUrl(NSUrl.FromString(urlString));
byte[] dataBytes = new byte[data.Length];
System.Runtime.InteropServices.Marshal.Copy(data.Bytes, dataBytes, 0, Convert.ToInt32(data.Length));
I got an answer to this question from the reply by Dimitris Tavlikos to this question I asked:
How to read the contents of a local image into a base64 string in MonoTouch
From that answer I learnt that if you include a reference System.Linq then the NSData object will have a ToArray() method that will return an array of bytes. So with this namespace referenced you can do the following:
bytes[] dataBytes = data.ToArray();
Hope this info helps someone else.
Timo's answer as an extension method:
public static byte[] ToByteArray (this NSData data) {
var dataBytes = new byte[data.Length];
System.Runtime.InteropServices.Marshal.Copy(data.Bytes, dataBytes, 0, Convert.ToInt32(data.Length));
return dataBytes;
}
Related
I have been looking for ways to upload BASE64 binary files days and I am stuck.
First of all a do not know how to convert BASE64 binary file to array buffer, blob, ... Everything is about BASE64 string but I have BASE64 binary file.
Do you have any solution?
You need to convert this Base64 string to byte array. C# Programming provide several approaches to do this without trouble. Following Upload large files sample SharePoint Add-in and Convert.FromBase64String(String) Method, both at Microsoft Docs, the final code that meet your requirements will be like this:
//This approach is useful for short files, less than 2Mb:
public void UploadFileContentFromBase64(ClientContext ctx, string libraryName, string fileName, string base64Str)
{
Web web = ctx.Web;
// Ensure that target library exists. Create if it is missing.
if (!LibraryExists(ctx, web, libraryName))
{
CreateLibrary(ctx, web, libraryName);
}
FileCreationInformation newFile = new FileCreationInformation();
// The next line of code causes an exception to be thrown for files larger than 2 MB.
newFile.Content = Convert.FromBase64String(base64Str);
newFile.Url = fileName;
// Get instances to the given library.
List docs = web.Lists.GetByTitle(libraryName);
// Add file to the library.
Microsoft.SharePoint.Client.File uploadFile = docs.RootFolder.Files.Add(newFile);
ctx.Load(uploadFile);
ctx.ExecuteQuery();
}
//This other approach provides you to Upload large files, more than 2Mb:
public void UploadDocumentContentStreamFromBase64(ClientContext ctx, string libraryName, string fileName, string base64Str)
{
Web web = ctx.Web;
// Ensure that the target library exists. Create it if it is missing.
if (!LibraryExists(ctx, web, libraryName))
{
CreateLibrary(ctx, web, libraryName);
}
byte[] fileContent = Convert.FromBase64String(base64Str);
using (MemoryStream memStream = new MemoryStream(fileContent))
{
FileCreationInformation flciNewFile = new FileCreationInformation();
// This is the key difference for the first case - using ContentStream property
flciNewFile.ContentStream = memStream;
flciNewFile.Url = fileName;
flciNewFile.Overwrite = true;
List docs = web.Lists.GetByTitle(libraryName);
Microsoft.SharePoint.Client.File uploadFile = docs.RootFolder.Files.Add(flciNewFile);
ctx.Load(uploadFile);
ctx.ExecuteQuery();
}
}
Have been stringbuilding CSV files for ages on MVC applications just fine, until now.
One mistake made me generate a CSV string bigger then the system can handle in memory, so i have been searching the web for any solution on minifing a string that could be reconstructed back on client.
So far i have been doing this:
StringBUilder sb = new StringBuilder();
foreach(stuff in manyEnumerableStuff)
sb.Append(stuff);
return csv.ToString().ToBase64();
public static string ToBase64(this string value) => Convert.ToBase64String(Encoding.Default.GetBytes(value));
The application can handle .ToString() in this HUGE case just "fine", but it fails without creating excpetions at .ToBase64String(Encoding.Default.GetBytes(value));
This only happens on huge strings because from what i know, base64 will make the string 33% bigger.
Compressed json can't solve this problem, since this happens on server side.
So I have gonne on search to minify or compress this string, but it still need to be a string and can be converted on client site Angular application.
I have found this:
public static string compress(this string big) {
var bytes = Encoding.Default.GetBytes(big);
using (var msi = new MemoryStream(bytes))
using (var mso = new MemoryStream()) {
using (var gs = new GZipStream(mso, CompressionMode.Compress)) {
//msi.CopyTo(gs);
CopyTo(msi, gs);
}
return mso.ToArray().ToString();
}
}
private static void CopyTo(Stream src, Stream dest) {
byte[] bytes = new byte[4096];
int cnt;
while ((cnt = src.Read(bytes, 0, bytes.Length)) != 0) {
dest.Write(bytes, 0, cnt);
}
}
but I think there is no sense at all, because i can't put byte[] on json value as string without converting it back.
Is it possible to compress plain Pipe separated values that represents a .CSV file after getting the string from StringBuilder()?
I have tried GC.collect() right after parsing SB to string but still broke the application.
I'm on .Net Core 2.1, Linux server.
I'm trying to write code to convert a GIF annimation file into a base64 string and then convert it from base 64 string back into an image. The code I've written is for standard image files (i.e. Bitmap, JPEG, GIF). Animated GIFs, however, are different and obviously require a different step-by-step.
Here is the code I've written for converting an image to base64 string:
if (pbTitlePageImage.Image != null)
{
// This is the step-by-step for writing an image to binary.
string Image2BConverted;
using (Bitmap bm = new Bitmap(pbTitlePageImage.Image))
{
using (MemoryStream ms = new MemoryStream())
{
BinaryWriter bw = new BinaryWriter(ms);
bm.Save(ms, ImageFormat.Jpeg);
Image2BConverted = Convert.ToBase64String(ms.ToArray());
GameInfo.TitlePageImage = Image2BConverted;
bw.Close();
ms.Close();
GameInfo.TitlePageImagePresent = true;
ProjectNeedsSaving = true;
}
}
}
And here is the code I've written for converting a base64 string back to an image:
{
byte[] TitlePageImageBuffer = Convert.FromBase64String(GameInfo.TitlePageImage);
MemoryStream memTitlePageImageStream = new MemoryStream(TitlePageImageBuffer, 0, TitlePageImageBuffer.Length);
memTitlePageImageStream.Write(TitlePageImageBuffer, 0, TitlePageImageBuffer.Length);
memTitlePageImageStream.Position = 0;
pbTitlePageImage.Image = Bitmap.FromStream(memTitlePageImageStream, true);
memTitlePageImageStream.Close();
memTitlePageImageStream = null;
TitlePageImageBuffer = null;
}
After converting the base64 string back into an image, it must be loaded into a picturebox. The above code examples will work, but only the first image in the animation chain makes it through and thus is the only part if the animation that appears in the picturebox. I need to write code that will handle the entire animation. Thanks in advance!
I found a way to solve it:
byte[] imageByte = Base64.decodeBase64(imageData.getImageBase64());
new FileOutputStream("image2.gif");
write(imageByte);
close();
I dont know why, but using a FileOutput String i could get a file with the complete animation.
I've seen variations of my questions on stack overflow but haven't had any answers that have worked for me. I'm trying to convert an image I retrieve via UIImagePickerController to an NSData object. In the debugger after I call AsJPEG the NSData object has text that appears as...
System.Exception: Could not initialize an instance of the type 'MonoTouch.Foundation.NSString': the native 'initWithDa…
(note the debugger cuts off the string)
My code is fairly straight forward (taken form samples on stack overflow)
protected void Handle_FinishedPickingMedia (object sender, UIImagePickerMediaPickedEventArgs e) {
// determine what was selected, video or image
bool isImage = false;
switch(e.Info[UIImagePickerController.MediaType].ToString()) {
case "public.image":
Console.WriteLine("Image selected");
isImage = true;
break;
case "public.video":
Console.WriteLine("Video selected");
break;
}
string path = Environment.GetFolderPath (Environment.SpecialFolder.MyDocuments);
path = Path.Combine (path, "media");
if (!Directory.Exists (path))
Directory.CreateDirectory (path);
path = Path.Combine (path, Path.GetRandomFileName ());
// get common info (shared between images and video)
NSUrl referenceURL = e.Info[new NSString("UIImagePickerControllerReferenceUrl")] as NSUrl;
if (referenceURL != null)
Console.WriteLine("Url:"+referenceURL.ToString ());
// if it was an image, get the other image info
if(isImage) {
// get the original image
UIImage originalImage = e.Info[UIImagePickerController.OriginalImage] as UIImage;
if(originalImage != null) {
// do something with the image
Console.WriteLine ("got the original image");
using (NSData imageData = originalImage.AsJPEG(0.75f)) {
byte[] dataBytes = new byte[imageData.Length];
System.Runtime.InteropServices.Marshal.Copy(imageData.Bytes, dataBytes, 0, Convert.ToInt32(imageData.Length));
File.WriteAllBytes (path, dataBytes);
}
}
} else { // if it's a video
// get video url
NSUrl mediaURL = e.Info[UIImagePickerController.MediaURL] as NSUrl;
if(mediaURL != null) {
// ...
}
}
// dismiss the picker
NavigationController.DismissViewController (true, null);
}
I've seen other posts that suggested it was the size of the UIImage, so I've experimented with cropping it. Same result. I've also tried AsPNG, same result. I even tried scaling down the image to 1/4 it's original size and still get the error.
I think the key is the mention of NSString, which tells me something's fishy... as the native C call used in Xcode doesn't involve an NSString, so I think something else is going on.
Any suggestions?
As noted in the comment from therealjohn, this appears to be an error with the debugger when it converts a value to a string to display it in the debugger window it seems to run into an error. The NSData object is actually fine.
I used this question
How do I convert an InputStream to a String in Java?
to convert an InputStream to a String with this code:
public static String convertStreamToString(java.io.InputStream is) {
java.util.Scanner s = new java.util.Scanner(is).useDelimiter("\\A");
return s.hasNext() ? s.next() : "";
}
My inputstream comes from an HttpURLConnection InputStream, and when I do my conversion to String, the inputstream changes and I cannot longer use it. This is the error that I get:
Premature end of file.' SOAP
What can I do to keep my inputstream, when I convert it to string with the proper information?.
Speciffically this is the information that changes:
inCache = true (before false)
keepAliveConnections = 4 (before 5)
keepingAlive = false (before true)
poster = null (before it was PosterOutputStream object with values)
Thank you.
If you pass your input stream into scanner or read its data in any other way. you actually consuming its data and there will be no available data in that stream anymore.
you may need to create a new input stream with same data and use it instead of the original one. for example:
ByteArrayOutputStream into = new ByteArrayOutputStream();
byte[] buf = new byte[4096];
// inputStream is your original stream.
for (int n; 0 < (n = inputStream.read(buf));) {
into.write(buf, 0, n);
}
into.close();
byte[] data = into.toByteArray();
//This is your data in string format.
String stringData = new String(data, "UTF-8"); // Or whatever encoding
//This is the new stream that you can pass it to other code and use its data.
ByteArrayInputStream newStream = new ByteArrayInputStream(data);
The scanner reads till the end of the stream and closes it. So it will not be available further. Use PushbackInputStream as a wrapper to your input stream and use the unread() method.
Try to Use Apache Utilities.
In my preset project, I have done the same thing
InputStream xml = connection.getInputStream();
String responseData = IOUtils.toString(xml);
You can get IOUtils from Apache [import org.apache.commons.io.IOUtils]