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Okio/Okhttp download file using BufferedSink and decode Base64 without having whole file in memory multiple times

Got a bit of a problem atm. for my "inapp"-update im downloading the new base64 encoded .apk from my webspace. I have the functionality pretty much down, this is the code without decoding.
public void onResponse(Call call, Response response) throws IOException {
if(response.isSuccessful()){
ResponseBody body = response.body();
BufferedSource source = body.source();
source.request(Long.MAX_VALUE);
Buffer buffer = source.buffer();
String rString = buffer.clone().readString(Charset.forName("UTF-8"));
Log.i("Test: ", AppUtils.decodeBase64(rString));
if(rString.equals("xxx")){
EventBus.getDefault().post(new KeyNotValid());
dispatcher.cancelAll();
}else{
EventBus.getDefault().post(new SaveKey(apikey));
BufferedSink sink = Okio.buffer(Okio.sink(myFile));
sink.writeAll(source);
sink.flush();
sink.close();
}
}
}
The Buffer/Log is not really necessary, just using it to check the response during testing.
How would i go about decoding the bytes before i write them to the sink?
I tried doing it via. ByteString, but i couldn't find a way to write the decoded String back to a BufferedSource.
Most alternatives are pretty slow like reopening the file afterwards, reading the bytes into memory, decode and write them back.
Would really appreciate any help on this
cheers

You can already consume the response as an InputStream via ResponseBody.byteStream. You can decorate this stream with https://commons.apache.org/proper/commons-codec/apidocs/org/apache/commons/codec/binary/Base64InputStream.html and use it to read a stream of bytes and write it to the Sink for the file in chunks.

I know this answer arrives quite late and that Yuri's answer is technically correct, but I think the most idiomatic way to do that is to take advantage of the composition pattern promoted by Okio to create a Source that decodes from Base64 (or a Sink that encodes to Base64, if you need so).
Here's a little proof of concept (I'm sure it can be improved):
public class Base64Source implements Source {
private Source delegate;
private Base64.Decoder decoder; // Using Java 8 API, but it can be any library
public Base64Source(Source delegate) {
this(delegate, Base64.getDecoder());
}
public Base64Source(Source delegate, Base64.Decoder decoder) {
this.delegate = delegate;
this.decoder = decoder;
}
#Override
public long read(Buffer sink, long byteCount) throws IOException {
Buffer buffer = new Buffer();
long actualRead = this.delegate.read(buffer, byteCount);
if (actualRead == -1) {
return -1;
}
byte[] encoded = buffer.readByteArray(actualRead);
byte[] decoded = decoder.decode(encoded);
sink.write(decoded);
return decoded.length;
}
#Override
public Timeout timeout() {
return this.delegate.timeout();
}
#Override
public void close() throws IOException {
this.delegate.close();
}
}
And here's how it can be used
BufferedSource source = Okio.buffer(new Base64Source(originalSource));
BufferedSink sink = ... // create sink
sink.writeAll(source);
// Don't forget to close the source/sink to flush and free resources
sink.close();
source.close();

How can receive multiple files in InputStream and process it accordingly?

I want to receive the multiple files uploaded from my client-side. I uploaded multiple files and request my server-side (Java) using JAX-RS(Jersey).
I have the following code,
#POST
#Consumes(MediaType.MULTIPART_FORM_DATA)
public void upload(#Context UriInfo uriInfo,
#FormDataParam("file") final InputStream is,
#FormDataParam("file") final FormDataContentDisposition detail) {
FileOutputStream os = new FileOutputStream("Path/to/save/" + appropriatefileName);
byte[] buffer = new byte[1024];
int length;
while ((length = is.read(buffer)) > 0) {
os.write(buffer, 0, length);
}
}
How can i write the files separately in the server side as uploaded in the client side.
For eg. I uploaded files such as My_File.txt, My_File.PNG, My_File.doc.
I need to write as same as the above My_File.txt, My_File.PNG, My_File.doc in the server side.
How can I achieve this?

You could try something like this:
#POST
#Consumes(MediaType.MULTIPART_FORM_DATA)
public void upload(FormDataMultiPart formParams)
{
Map<String, List<FormDataBodyPart>> fieldsByName = formParams.getFields();
// Usually each value in fieldsByName will be a list of length 1.
// Assuming each field in the form is a file, just loop through them.
for (List<FormDataBodyPart> fields : fieldsByName.values())
{
for (FormDataBodyPart field : fields)
{
InputStream is = field.getEntityAs(InputStream.class);
String fileName = field.getName();
// TODO: SAVE FILE HERE
// if you want media type for validation, it's field.getMediaType()
}
}
}

There is a blog for the scenario you are looking for. Hope this helps
http://opensourzesupport.wordpress.com/2012/10/27/multiple-file-upload-along-with-form-data-in-jax-rs/

Showing images outside my application using Tapestry5

I am developing my first project with Tapestry and I am about to finish, except for the images..
What do I want? I just need to display an image outside my application, example: /home/app/images/image.jpg
What did I try? I have been "googling" and reading Tapestry5 forums, I found this: http://wiki.apache.org/tapestry/Tapestry5HowToStreamAnExistingBinaryFile
I followed the steps, creating classes but I need to display the image embed on another page (so I can't use ImagePage), I tried this:
On page java class
public StreamResponse getImage() {
InputStream input = DetallesMultimedia.class
.getResourceAsStream("/home/santi/Escritorio/evolution-of-mario.jpg"); //On application, i will retrieve this from DB
return new JPEGInline(input,"hellow");
}
On page template
...
<img src="${image}" alt:image/>
...
or
...
${image}
...
Obviusly, this didn't work and I really don't know how can I do it. I read about loading the image on an event (returning the OutputStream on that event, as it's said in the HowTo linked above) but my english is so bad (I am sure you already noticed) and I don't understand well how can I do that.
Could you help me please?
Thanks you all.

I've never seen the examples as on the wiki page. Below some code on how to load an image on the classpath though using a StreamResponse.
#Inject
private ComponentResources resources;
#OnEvent(value = "GET_IMAGE_STREAM_EVENT")
private Object getProfilePic() throws Exception {
InputStream openStream = DetallesMultimedia.class.getResourceAsStream("/home/santi/Escritorio/evolution-of-mario.jpg");
byte[] imageBytes = IOUtils.toByteArray(openStream);
final ByteArrayInputStream output = new ByteArrayInputStream(imageBytes);
final StreamResponse response = new StreamResponse() {
public String getContentType() {
"image/jpegOrPngOrGif";
}
public InputStream getStream() throws IOException {
return output;
}
public void prepareResponse(Response response) {
// add response headers if you need to here
}
};
return response;
}
public String getPicUrl() throws Exception {
return resources.createFormEventLink("GET_IMAGE_STREAM_EVENT");
}
In your template:
<img src="${picUrl}"/>

is there an existing FileInputStream delete on close?

Is there an existing way to have a FileInputStream delete the underlying file automatically when closed?
I was planning to make my own utility class to extend FileInputStreamand do it myself, but I'm kinda surprised that there isn't something already existing.
edit: Use case is that I have a Struts 2 action that returns an InputStream for file download from a page. As far as I can tell, I don't get notified when the action is finished, or the FileInputStream is not in use anymore, and I don't want the (potentially large) temporary files that are generated to be downloaded left lying around.
The question wasn't Struts 2 specific, so I didn't include that info originally and complicate the question.

There's no such thing in the standard libraries, and not any of the apache-commons libs either , so something like:
public class DeleteOnCloseFileInputStream extends FileInputStream {
private File file;
public DeleteOnCloseFileInputStream(String fileName) throws FileNotFoundException{
this(new File(fileName));
}
public DeleteOnCloseFileInputStream(File file) throws FileNotFoundException{
super(file);
this.file = file;
}
public void close() throws IOException {
try {
super.close();
} finally {
if(file != null) {
file.delete();
file = null;
}
}
}
}

I know this is a fairly old question; however, it's one of the first results in Google, and Java 7+ has this functionality built in:
Path path = Paths.get(filePath);
InputStream fileStream = Files.newInputStream(path, StandardOpenOption.DELETE_ON_CLOSE);
There are a couple caveats with this approach though, they're written up here, but the gist is that the implementation makes a best effort attempt to delete the file when the input stream is closed, and if that fails makes another best effort attempt when the JVM terminates. It is intended for use with temp files that are used solely by a single instance of the JVM. If the application is security sensitive, there are also a few other caveats.

Can you can use File.deleteOnExit() before opening the file ?
EDIT: On you can subclass a FileInputStream that will delete the file on 'close()';
class MyFileInputStream extends FileInputStream
{
File file;
MyFileInputStream(File file) { super(file); this.file=file;}
public void close() { super.close(); file.delete();}
}

I know this is an old question, but I just ran into this issue, and found another answer: javax.ws.rs.core.StreamingOutput.
Here's how I used it:
File downloadFile = ...figure out what file to download...
StreamingOutput so = new StreamingOutput(){
public void write(OutputStream os) throws IOException {
FileUtils.copyFile(downloadFile, os);
downloadFile.delete();
}
ResponseBuilder response = Response.ok(so, mimeType);
response.header("Content-Disposition", "attachment; filename=\""+downloadFile.getName()+"\"");
result = response.build();

JSP compilation to string or in memory bytearray with Tomcat/Websphere

I am doing conversion to image and PDF output. I need an input HTML document that is generated by our application JSPs. Essentially, I need to render the final output product of a JSP based application to a String or memory and then use that string for other processing.
What are some ways that I can just invoke the JSP renderer to get the final HTML content that is normally output to the user?
Ideally, I am looking for something that will work for multiple application servers like websphere. But something that is Tomcat specific will also work.
There are a couple of other different approaches, but I think rendering the JSP (which may include sub JSPs) is the best approach.
Optional Paths that I would rather stay away from.
I could perform a network request to the page using the Socket APIs and then read the final output that is rendered from that particular page. This is probably the next best option, but we work on multiple servers and JVMs, targeting the page I need would be complicated.
Use a filter to get that final page output. This Ok but I have always had problems with filters and illegalstateexceptions. It never seems to work 100% the way I need to.
It seems like this should be simple. The JSP compiler is essentially just a library for parsing an input JSP document and subdocuments and then output some HTML content. I would like to invoke that process through Java code. On the server and possibly as a standalone console application.

This is a downright irritating problem, one I've had to handle a few times and one I've never found a satisfactory solution to.
The basic problem is that the servlet API is of no help here, so you have to trick it. My solution is to write a subclass of HttpServletResponseWrapper which override the getWriter() and getOutput() methods and captures the data into a buffer. You then forward() your request to the URI of the JSP you want to capture, substituting your wrapper response for the original response. You then extract the data from the buffer, manipulate it, and write the end result back to the original response.
Here's my code that does this:
public class CapturingResponseWrapper extends HttpServletResponseWrapper {
private final OutputStream buffer;
private PrintWriter writer;
private ServletOutputStream outputStream;
public CapturingResponseWrapper(HttpServletResponse response, OutputStream buffer) {
super(response);
this.buffer = buffer;
}
#Override
public ServletOutputStream getOutputStream() {
if (outputStream == null) {
outputStream = new DelegatingServletOutputStream(buffer);
}
return outputStream;
}
#Override
public PrintWriter getWriter() {
if (writer == null) {
writer = new PrintWriter(buffer);
}
return writer;
}
#Override
public void flushBuffer() throws IOException {
if (writer != null) {
writer.flush();
}
if (outputStream != null) {
outputStream.flush();
}
}
}
The code to use it can be something like this:
HttpServletRequest originalRequest = ...
HttpServletResponse originalResponse = ...
ByteArrayOutputStream bufferStream = new ByteArrayOutputStream();
CapturingResponseWrapper responseWrapper = new CapturingResponseWrapper(originalResponse, bufferStream);
originalRequest.getRequestDispatcher("/my.jsp").forward(originalRequest, responseWrapper);
responseWrapper.flushBuffer();
byte[] buffer = bufferStream.toByteArray();
// now use the data
It's very ugly, but it's the best solution I've found. In case you're wondering, the wrapper response has to contain the original response because the servlet spec says that you cannot substitute a completely different request or response object when you forward, you have to use the originals, or wrapped versions of them.