I am currently making an app for students where they can upload a PDF file to a server. I am using the android Volley API but have been testing the function using JPEG files.
This is my code
public String getStringImage(Bitmap bmp) {
ByteArrayOutputStream baos = new ByteArrayOutputStream();
bmp.compress(Bitmap.CompressFormat.JPEG, 100, baos);
byte[] imageBytes = baos.toByteArray();
String encodedImage = Base64.encodeToString(imageBytes, Base64.DEFAULT);
return encodedImage;
}
How would I change this code so that a PDF can be uploaded instead?
Do I still used Base64? and imageBytes?
Or is there an alternate method?
You should be able to reuse most of the code that you have there, instead of taking in a Bitmap, you would take in a File. You won't be able to use Bitmap.Compress on it though so that will need to be removed.
For uploading a PDF, you can Base64 encode it and send it as a string as part of the request, this might get out of control if you are handling large files.
The other option is to use a multipart form, I would suggest taking a look at this stackoverflow question and answer for how to do that.
Related
I want to open and view a password protected PDF file in VB6/VB.NET program. I have tried using the Acrobat PDF Library but could not do it.
The reason I want to create a password protected PDF file is because I dont want the PDF file to be opened without the password externally i.e outside the program.
To open a password protected PDF you will need to develop at least a PDF parser, decryptor and generator. I wouldn't recommend to do that, though. It's nowhere near an easy task to accomplish.
With help of a PDF library everything is much simpler. You might want to try Docotic.Pdf library for the task.
Here is a sample for you task:
public static void unprotectPdf(string input, string output)
{
bool passwordProtected = PdfDocument.IsPasswordProtected(input);
if (passwordProtected)
{
string password = null; // retrieve the password somehow
using (PdfDocument doc = new PdfDocument(input, password))
{
// clear both passwords in order
// to produce unprotected document
doc.OwnerPassword = "";
doc.UserPassword = "";
doc.Save(output);
}
}
else
{
// no decryption is required
File.Copy(input, output, true);
}
}
Docotic.Pdf can also extract text (formatted or not) from PDFs. It might be useful for indexing (I guess it's what you are up to because you mentioned Adobe IFilter)
you can convert code to vb over the internet
I have a mvc 4.5 application where I show a grid. The first column of the grid is a document name. The document name is an hyper link to the actual document that is hosted on our site and is available via a url. The documents can be pdf or doc or ppt. I can access these documents only via url and I do not have access to the actual physical document on our server.
I am providing users an option to select one or many of these documents from the grid and then they can download them. What I am trying to achieve is read each of the selected documents via the url and write it to a zip file and make the zip file downloadable. So users will be downloading one file instead of multiple files.
I have tried to stream the documents via url in memory and then add it to the zip file using ZipArchive Library from Microsoft. This is not working for me.
I was able to add documents that was on disk to zip file using Zip Archive and it works great. But I do not have access to the physical document as I can access the documents only through URL. My next option is to download each of these documents into a temp location on server and then add it to zip file using Zip Archive.But I am trying to avoid downloading files into a temp location
Please suggest how I can achieve reading documents via url in memory and adding each of these document to zip file and make zip file downloadable.
Any help will be appreciated.
Thank you Cbroe for commenting. I figured the answer. The problem was I was reading the pdf from the url and convert it to a memory stream and then was trying to add the memory stream to ZipArchive which was not working but instead I extracted the byte array out of the memory stream and then added it to the zip archive and it worked.
Here is the code snippet that might be useful for some one. My first contribution to Stack OverFlow.
public FileResult DownloadZip()
{
MemoryStream memoryStream = new MemoryStream();
using (var archive = new ZipArchive(memoryStream, ZipArchiveMode.Create, true))
{
var demoFile = archive.CreateEntry("Pdf123.pdf");
var convertedStream = ConvertTobyte("http://www.example.com/Pdf123.pdf");
using (var entryStream = demoFile.Open())
{
entryStream.Write(convertedStream, 0, convertedStream.Length);
}
demoFile = archive.CreateEntry("Pdf456.pdf");
convertedStream = ConvertTobyte("http://www.example.com/Pdf456.pdf");
using (var entryStream = demoFile.Open())
{
entryStream.Write(convertedStream, 0, convertedStream.Length);
}
}
//This option is to write the zip to your local disk
using (var fileStream = new FileStream(#"C:\Temp\test.zip", FileMode.Create))
{
memoryStream.Seek(0, SeekOrigin.Begin);
memoryStream.CopyTo(fileStream);
}
//This option is to donload the zip via browser
memoryStream.Seek(0, SeekOrigin.Begin);
return new FileStreamResult(memoryStream, "application/zip")
{
FileDownloadName = "Archive.zip"
};
}
private static byte[] ConvertTobyte(string fileUrl)
{
byte[] imageData = null;
using (var wc = new System.Net.WebClient())
imageData = wc.DownloadData(fileUrl);
return imageData;
}
I am confused about Object single upload and multipart upload. Both are taking consumes same time. My code is below:
File file = new File("D:\\AmazonS3\\aws-java-sdk-1.8.3\\lib\\aws-java-sdk-1.8.3-javadoc.jar");
FileInputStream fis = new FileInputStream(file);
String keyName = System.currentTimeMillis()+"_aws-java-sdk-1.8.3-javadoc.jar";
ObjectMetadata metaData = new ObjectMetadata();
metaData.addUserMetadata("test","TEST");
//Object single upload
PutObjectRequest putobejcObjectRequest = new PutObjectRequest(BUCKET_NAME, keyName, fis,metaData);
putobejcObjectRequest.setMetadata(metaData);
s3client.putObject(putobejcObjectRequest);
//Object multipart upload
TransferManagerConfiguration configuration = new TransferManagerConfiguration();
configuration.setMultipartUploadThreshold(5*com.amazonaws.services.s3.internal.Constants.MB);
TransferManager transferManager = new TransferManager(s3client);
transferManager.setConfiguration(configuration);
Upload upload = transferManager.upload(BUCKET_NAME, keyName, fis,metaData);
upload.waitForCompletion();
transferManager.shutdownNow();
Please help me, Is there any problem in my code.
I've faced the same problem and found (by inspecting SDK code) that transfer manager will use parallel parts upload only if you pass it file, not the InputStream.
Look at decision code from sdk (version 1.8.9):
if (TransferManagerUtils.isUploadParallelizable(putObjectRequest, isUsingEncryption)) {
captureUploadStateIfPossible();
uploadPartsInParallel(requestFactory, multipartUploadId);
return null;
} else {
return uploadPartsInSeries(requestFactory);
}
where is uploadParallelizable:
// Each uploaded part in an encrypted upload depends on the encryption context
// from the previous upload, so we cannot parallelize encrypted upload parts.
if (isUsingEncryption) return false;
// Otherwise, if there's a file, we can process the uploads concurrently.
return (getRequestFile(putObjectRequest) != null);
So, if you want to get advantage of parallel upload in parts, pass a file to TransferManager.
When uploading options from a stream, callers must supply the size of
options in the stream through the content length field in the
ObjectMetadata parameter. If no content length is specified for the
input stream, then TransferManager will attempt to buffer all the
stream contents in memory and upload the options as a traditional,
single part upload. Because the entire stream contents must be
buffered in memory, this can be very expensive, and should be avoided
whenever possible.
source: https://docs.aws.amazon.com/AWSJavaSDK/latest/javadoc/com/amazonaws/services/s3/transfer/TransferManager.html#upload-java.lang.String-java.lang.String-java.io.InputStream-com.amazonaws.services.s3.model.ObjectMetadata-
Quick search here yielded nothing. So, I have started using some rather roundabout ways to use StreamWriter in my WinRT Application. Reading works well, writing works differently. What' I'm seeing is that when I select my file to write, if I choose a new file then no problem. The file is created as I expect. If I choose to overwrite a file, then the file is overwritten to a point, but the point where the stream stops writing, if the original file was large, then the old contents exist past where my new stream writes.
The code is as such:
public async void WriteFile(StorageFile selectedFileToSave)
{
// At this point, selectedFileToSave is from the Save File picker so can be a enw or existing file
StreamWriter writeStream;
Encoding enc = new UTF8Encoding();
Stream dotNetStream;
dotNetStream = await selectedFileToSave.OpenStreamForWriteAsync();
StreamWriter writeStream = new StreamWriter(dotNetStream, enc);
// Do writing here
// Close
writeStream.Write(Environment.NewLine);
await writeStream.FlushAsync();
await dotNetStream.FlushAsync();
}
Can anyone offer clues on what I could be missing? There are lots of functions missing in WinRT, so not really following ways to get around this
Alternatively you can set length of the stream to 0 with SetLength method before using StreamWriter:
var stream = await file.OpenStreamForWriteAsync();
stream.SetLength(0);
using (var writer = new StreamWriter(stream))
{
writer.Write(text);
}
Why not just use the helper methods in FileIO class? You could call:
FileIO.WriteTextAsync(selectedFileToSave, newTextContents);
If you really need a StreamWriter, first truncate the file by calling
FileIO.WriteBytesAsync(selectedFileToSave, new byte[0]);
And then continue with your existing code.
I'm trying to return a stream in WCF 3.5 using a REST-Style URL instead of SOAP. The idea is to read a file from SharePoint 2010, then pass it back to the client. (We have reasons for doing it this way instead of using SharePoint services, but I digress.) It appears as though the only way to send the file is by writing it to the filesystem using one FileStream, then using File.OpenRead to return the stream back to the client. Using a MemoryStream doesn't seem to work. IE prompts for the file save, but the file comes down as like 2KB and then can't be read of course because it's not all there. Any ideas?
SPListItemCollection lookupFld2 = docLibrary.GetItems(spQuery2);
if (lookupFld2.Count > 0)
{
WebOperationContext.Current.OutgoingResponse.ContentType =
"application/octet-stream";
WebOperationContext.Current.OutgoingResponse.Headers.Add(
"Content-Disposition","attachment; filename=" + lookupFld2[0].File.Name);
MemoryStream memoryStream =
(MemoryStream)lookupFld2[0].File.OpenBinaryStream();
memoryStream.Position = 0;
return memoryStream;
}
Technically, OpenBinaryStream only returns a general Stream instance NOT a MemoryStream (http://msdn.microsoft.com/en-us/library/ms470901.aspx). If you want a MemoryStream you need to create a new one and copy the contents from the BinaryStream into the MemoryStream then reset the position and return it.