Develop Reference

In Groovy, how to properly get the file from HttpServletRequest

I am writing a REST API in Groovy script that will receive a file upload from client side.
The REST API will receive the file via HttpServletRequest.
I am trying to get the file from HttpServletRequest by getting its InputStream, then convert it to File to save to proper folder.
My code is as below:
RestApiResponse doHandle(HttpServletRequest request, RestApiResponseBuilder apiResponseBuilder, RestAPIContext context) {
InputStream inputStream = request.getInputStream()
def file = new File(tempFolder + "//" + fileName)
FileOutputStream outputStream = null
try
{
outputStream = new FileOutputStream(file, false)
int read;
byte[] bytes = new byte[DEFAULT_BUFFER_SIZE];
while ((read = inputStream.read(bytes)) != -1) {
outputStream.write(bytes, 0, read);
}
}
finally {
if (outputStream != null) {
outputStream.close();
}
}
inputStream.close();
// the rest of the code
}
The files are created, but all of them are corrupted.
When I try to open them with Notepad, all of them have, at the beginning, some thing similar to the below:
-----------------------------134303111730200325402357640857
Content-Disposition: form-data; name="pbUpload1"; filename="Book1.xlsx"
Content-Type: application/vnd.openxmlformats-officedocument.spreadsheetml.sheet
Am I doing this wrong? How do I get the file correctly?

Found the solution with MultipartStream
import org.apache.commons.fileupload.MultipartStream
import org.apache.commons.io.FileUtils
InputStream inputStream = request.getInputStream()
//file << inputStream;
String fileName = "";
final String CD = "Content-Disposition: "
MultipartStream multipartStream = new MultipartStream(inputStream, boundary);
//Block below line because it always return false for some reason
// but should be used as stated in document
//boolean nextPart = multipartStream.skipPreamble();
//Block below line as in my case, the part I need is at the first part
// or maybe I should use it and break after successfully get the file name
//while(nextPart) {
String[] headers = multipartStream.readHeaders().split("\\r\\n")
ContentDisposition cd = null
for (String h in headers) {
if (h.startsWith(CD)) {
cd = new ContentDisposition(h.substring(CD.length()));
fileName = cd.getParameter("filename"); }
}
def file = new File(tempFolder + "//" + fileName)
ByteArrayOutputStream output = new ByteArrayOutputStream(1024)
try
{
multipartStream.readBodyData(output)
FileUtils.writeByteArrayToFile(file, output.toByteArray());
}
finally {
if (output != null) {
output.flush();
output.close();
}
}
inputStream.close();

Unexpected character encountered while parsing value when validating content as JSON in WOPI

I am currently implementing the WOPI with my application. Our domain is already whitelisted by Microsoft. While implementation I am currently facing two problems as mentioned below:
The exception is thrown when trying to validate content as JSON: 'Unexpected character encountered while parsing value.' I am sending my response "Value=application/octet-stream" but I don't understand why the server is trying to parse the stream as JSON.
After every new request coming from "iframe" is initiating a new session in the JAVA.
Here are more details:
My current URL is https://onenote.officeapps-df.live.com/hosting/WopiTestFrame.aspx?ui=en-US&rs=en-US&dchat=1&hid=26D7CA2A10F60A68720106BF599F84B9&&WOPISrc=https://domain/wopiEditor/files/73346e47-697b-11e6-a8bc-c26cd8f74b91/courses/independentConcepts/concept_adminGlo_5/assets/Setting url for static ip.docx&access_token=DEADBEEFDEADBEEFDEADBEEF&access_token_ttl=1532765580679
And My Java code is as following:
public void getFile(HttpServletRequest request, HttpServletResponse response, String name) {
Println.getInstance().log(request.getSession().getId() + "re" + request.getRequestURI());
InputStream fis = null;
OutputStream toClient = null;
try {
String path = getFilePath(request) + name;
File file = new File(path);
String filename = file.getName();
// XWPFDocument xDoc = new XWPFDocument(OPCPackage.open(fis));
fis = new BufferedInputStream(new FileInputStream(path));
byte[] buffer = new byte[fis.available()];
fis.read(buffer);
response.reset();
response.addHeader("Content-Disposition",
"attachment;filename=" + new String(filename.getBytes("utf-8"), "ISO-8859-1"));
response.addHeader("Content-Length", "" + file.length());
response.addHeader("Content-Type", "" + "application/octet-stream");
//Println.getInstance().log(file.length() + "l" + file);
toClient = new BufferedOutputStream(response.getOutputStream());
response.setContentType("application/octet-stream");
toClient.write(buffer);
toClient.flush();
} catch (IOException ex) {
ex.printStackTrace();
} finally {
try {
fis.close();
toClient.close();
} catch (IOException e) {
e.printStackTrace();
}
}
}
The test frame image is attached

The error you are seeing is on the CheckFileInfo request which is supposed to be returned as JSON. The Java snippit that you provided is for the getFile request which is a separate call that is made from the Office Online server. You should look over https://wopi.readthedocs.io/projects/wopirest/en/latest/ for how to write your implementation.

One thought is maybe you need to set the Content-Type header more specifically instead of the application/octet-stream you are sending?
Also there are quite a lot of other header values you are supposed to be returning, some of them may matter as well:
https://wopi.readthedocs.io/projects/wopirest/en/latest/common_headers.html#common-headers

Blank pages in pdf after downloading it from web

I am trying to download a PDF file with HttpClient, it is downloading the PDF file but pages are blank. I can see the bytes on console from response if I print them. But when I try to write it to file it is producing a blank file.
FileUtils.writeByteArrayToFile(new File(outputFilePath), bytes);
However the file is showing correct size of 103KB and 297KB as expected but its just blank!!
I tried with Output stream as well like:
FileOutputStream fileOutputStream = new FileOutputStream(outFile);
fileOutputStream.write(bytes);
Also tried to write with UTF-8 coding like:
Writer out = new BufferedWriter( new OutputStreamWriter(
new FileOutputStream(outFile), "UTF-8"));
String str = new String(bytes, StandardCharsets.UTF_8);
try {
out.write(str);
} finally {
out.close();
}
Nothing is working for me. Any suggestion is highly appreciated..
Update: I am using DefaultHttpClient.
HttpGet httpget = new HttpGet(targetURI);
HttpResponse response = null;
String htmlContents = null;
try {
httpget = new HttpGet(url);
response = httpclient.execute(httpget);
InputStreamReader dataStream=new InputStreamReader(response.getEntity().getContent());
byte[] bytes = IOUtils.toByteArray(dataStream);
...

You do
InputStreamReader dataStream=new InputStreamReader(response.getEntity().getContent());
byte[] bytes = IOUtils.toByteArray(dataStream);
As has already been mentioned in comments, using a Reader class can damage binary data, e.g. PDF files. Thus, you should not wrap your content in an InputStreamReader.
As your content can be used to construct an InputStreamReader, though, I assume response.getEntity().getContent() returns an InputStream. Such an InputStream usually can be directly used as IOUtils.toByteArray argument.
So:
InputStream dataStream=response.getEntity().getContent();
byte[] bytes = IOUtils.toByteArray(dataStream);
should already work for you!

Here is a method I use to download a PDF file from a specific URL. The method requires two string arguments, an url string (example: "https://www.ibm.com/support/knowledgecenter/SSWRCJ_4.1.0/com.ibm.safos.doc_4.1/Planning_and_Installation.pdf") and a destination folder path to download the PDF file (or whatever) into. If the destination path does not exist within the local file system then it is automatically created:
public boolean downloadFile(String urlString, String destinationFolderPath) {
boolean result = false; // will turn to true if download is successful
if (!destinationFolderPath.endsWith("/") && !destinationFolderPath.endsWith("\\")) {
destinationFolderPath+= "/";
}
// If the destination path does not exist then create it.
File foldersToMake = new File(destinationFolderPath);
if (!foldersToMake.exists()) {
foldersToMake.mkdirs();
}
try {
// Open Connection
URL url = new URL(urlString);
// Get just the file Name from URL
String fileName = new File(url.getPath()).getName();
// Try with Resources....
try (InputStream in = url.openStream(); FileOutputStream outStream =
new FileOutputStream(new File(destinationFolderPath + fileName))) {
// Read from resource and write to file...
int length = -1;
byte[] buffer = new byte[1024]; // buffer for portion of data from connection
while ((length = in.read(buffer)) > -1) {
outStream.write(buffer, 0, length);
}
}
// File Successfully Downloaded");
result = true;
}
catch (MalformedURLException ex) { ex.printStackTrace(); }
catch (IOException ex) { ex.printStackTrace(); }
return result;
}

Download Excel File Via Servlet

I am using the below code invoked via ajax call for create my excel file.On click the download button excel file gets generate at the root location. But I am not able to see the prompt for user to save/save as the file. I can see the response tab of browser where the content of excel are coming. But I want that Save As dialog option to come. Any correction in below code that can solve this issue?
final Date date = new Date();
final String generateDate= new SimpleDateFormat("yyyy-MM-dd").format(date);
final String filename = form_name+"-extraction-"+generateDate.toString()+".xls";
final FileOutputStream fileOutputStream = new FileOutputStream(filename);
workbook.write(fileOutputStream);
downloadFile(filename, response);
Below is download file method :
private void downloadFile(final String fileName, final SlingHttpServletResponse response){
try {
final File f = new File(fileName);
response.setContentType("application/vnd.ms-excel");
response.setHeader("Content-Disposition", "inline; filename="+fileName);
response.setHeader("Pragma", "public");
response.setHeader("Cache-Control", "no-store");
response.addHeader("Cache-Control", "max-age=0");
FileInputStream fin = null;
try {
fin = new FileInputStream(f);
} catch (final FileNotFoundException e) {
e.printStackTrace();
}
final int size = 1024;
try {
response.setContentLength(fin.available());
final byte[] buffer = new byte[size];
ServletOutputStream os = null;
os = response.getOutputStream();
int length = 0;
while ((length = fin.read(buffer)) != -1) {
os.write(buffer, 0, length);
}
fin.close();
os.flush();
os.close();
} catch (final IOException e) {
e.printStackTrace();
}
}catch (final Exception ex){
LOGGER.error("ERROR IS ::: {}",ex.getMessage());
}

If the disposition type matches "attachment" (case-insensitively),
this indicates that the recipient should prompt the user to save the
response locally, rather than process it normally (as per its media
type).
On the other hand, if it matches "inline" (case-insensitively),
this implies default processing. Therefore, the disposition type
"inline" is only useful when it is augmented with additional
parameters, such as the filename (see below).
Unknown or unhandled disposition types SHOULD be handled by
recipients the same way as "attachment" (see also [RFC2183],
Section 2.8).
So you are forcing the browser to show the file instead of downloading it with your
response.setHeader("Content-Disposition", "inline; filename="+fileName);
call. You should use "attachment" instead of "inline".
response.setHeader("Content-Disposition", "attachment; filename="+fileName);
Read Use of the Content-Disposition Header Field in the Hypertext Transfer Protocol (HTTP) for more info.

If previous searched data output is populated in Excel, you should remove static declarations. For example:
private static hasmap hs = new hashmap();

file upload using java servlet as a service without a web browser

I am very new to java and servlet programming.
I am not sure whether it is possible to write a servlet which when passed a URL from the local client machine, uploads the file to the server.
basically on the client machine we have a C# program and on the server side we have Apache-tomcat installed. I need to upload file(s) to the server using C# program on client machine.
Should I provide any more information (?)
Thanks in Advance

Note this code illustrates the general idea and not guaranteed to work without modification.
The C# file upload part
// this code shows you how the browsers wrap the file upload request, you still can fine a way simpler code to do the same thing.
public void PostMultipleFiles(string url, string[] files)
{
string boundary = "----------------------------" + DateTime.Now.Ticks.ToString("x");
HttpWebRequest httpWebRequest = (HttpWebRequest)WebRequest.Create(url);
httpWebRequest.ContentType = "multipart/form-data; boundary=" + boundary;
httpWebRequest.Method = "POST";
httpWebRequest.KeepAlive = true;
httpWebRequest.Credentials = System.Net.CredentialCache.DefaultCredentials;
Stream memStream = new System.IO.MemoryStream();
byte[] boundarybytes =System.Text.Encoding.ASCII.GetBytes("\r\n--" + boundary +"\r\n");
string formdataTemplate = "\r\n--" + boundary + "\r\nContent-Disposition: form-data; name=\"{0}\";\r\n\r\n{1}";
string headerTemplate = "Content-Disposition: form-data; name=\"{0}\"; filename=\"{1}\"\r\n Content-Type: application/octet-stream\r\n\r\n";
memStream.Write(boundarybytes, 0, boundarybytes.Length);
for (int i = 0; i < files.Length; i++)
{
string header = string.Format(headerTemplate, "file" + i, files[i]);
//string header = string.Format(headerTemplate, "uplTheFile", files[i]);
byte[] headerbytes = System.Text.Encoding.UTF8.GetBytes(header);
memStream.Write(headerbytes, 0, headerbytes.Length);
FileStream fileStream = new FileStream(files[i], FileMode.Open,
FileAccess.Read);
byte[] buffer = new byte[1024];
int bytesRead = 0;
while ((bytesRead = fileStream.Read(buffer, 0, buffer.Length)) != 0)
{
memStream.Write(buffer, 0, bytesRead);
}
memStream.Write(boundarybytes, 0, boundarybytes.Length);
fileStream.Close();
}
httpWebRequest.ContentLength = memStream.Length;
Stream requestStream = httpWebRequest.GetRequestStream();
memStream.Position = 0;
byte[] tempBuffer = new byte[memStream.Length];
memStream.Read(tempBuffer, 0, tempBuffer.Length);
memStream.Close();
requestStream.Write(tempBuffer, 0, tempBuffer.Length);
requestStream.Close();
try
{
WebResponse webResponse = httpWebRequest.GetResponse();
Stream stream = webResponse.GetResponseStream();
StreamReader reader = new StreamReader(stream);
string var = reader.ReadToEnd();
}
catch (Exception ex)
{
response.InnerHtml = ex.Message;
}
httpWebRequest = null;
}
and to understand how the above code was written you might wanna take a look at How does HTTP file upload work?
POST /upload?upload_progress_id=12344 HTTP/1.1
Host: localhost:3000
Content-Length: 1325
Origin: http://localhost:3000
... other headers ...
Content-Type: multipart/form-data; boundary=----WebKitFormBoundaryePkpFF7tjBAqx29L
------WebKitFormBoundaryePkpFF7tjBAqx29L
Content-Disposition: form-data; name="MAX_FILE_SIZE"
100000
------WebKitFormBoundaryePkpFF7tjBAqx29L
Content-Disposition: form-data; name="uploadedfile"; filename="hello.o"
Content-Type: application/x-object
... contents of file goes here ...
------WebKitFormBoundaryePkpFF7tjBAqx29L--
and finally all you have to do is to implement a servlet that can handle the file upload request, then you do whatever that you want to do with the file, take a look at this file upload tutorial
protected void processRequest(HttpServletRequest request,
HttpServletResponse response)
throws ServletException, IOException {
response.setContentType("text/html;charset=UTF-8");
// Create path components to save the file
final String path = request.getParameter("destination");
final Part filePart = request.getPart("file");
final String fileName = getFileName(filePart);
OutputStream out = null;
InputStream filecontent = null;
final PrintWriter writer = response.getWriter();
try {
out = new FileOutputStream(new File(path + File.separator
+ fileName));
filecontent = filePart.getInputStream();
int read = 0;
final byte[] bytes = new byte[1024];
while ((read = filecontent.read(bytes)) != -1) {
out.write(bytes, 0, read);
}
writer.println("New file " + fileName + " created at " + path);
LOGGER.log(Level.INFO, "File{0}being uploaded to {1}",
new Object[]{fileName, path});
} catch (FileNotFoundException fne) {
writer.println("You either did not specify a file to upload or are "
+ "trying to upload a file to a protected or nonexistent "
+ "location.");
writer.println("<br/> ERROR: " + fne.getMessage());
LOGGER.log(Level.SEVERE, "Problems during file upload. Error: {0}",
new Object[]{fne.getMessage()});
} finally {
if (out != null) {
out.close();
}
if (filecontent != null) {
filecontent.close();
}
if (writer != null) {
writer.close();
}
}
}
private String getFileName(final Part part) {
final String partHeader = part.getHeader("content-disposition");
LOGGER.log(Level.INFO, "Part Header = {0}", partHeader);
for (String content : part.getHeader("content-disposition").split(";")) {
if (content.trim().startsWith("filename")) {
return content.substring(
content.indexOf('=') + 1).trim().replace("\"", "");
}
}
return null;
}