I have a java bean which I use to download files from the server.
public void download(String filePath) throws IOException {
try {
String fn = new File(filePath).getName();
byte[] data = grabFile(filePath);
XspHttpServletResponse response = (XspHttpServletResponse)FacesContext.getCurrentInstance().getExternalContext().getResponse();
response.setContentType(URLConnection.guessContentTypeFromName(fn));
response.setHeader("Content-disposition", "attachment; filename=" + fn);
OutputStream output = response.getOutputStream();
output.write(data);
output.close();
}catch(Exception e) {
}finally {
FacesContext.getCurrentInstance().responseComplete();
}
}
I can call this bean from a link on my xpage using the following SSJS code, I am using full refresh in the link.
var dw = new FileShare();
dw.download("c:\test\filename.docx")
The code works fine, the file is downloaded from the server at the location when I click the link but it only works the first time. If I reload the whole page using the browser refresh button I can download another file.
How can I fix this code so that I can click to download from all links I have on my xpage without reloading the browser.
You have to use XSP.allowSubmit() in your link.
Check Per Henrik Lausten answer here (the one validated) for more details
Renaud
I'm writing a play 2.0 java application that allows users to upload files. Those files are stored on a third-party service I access using a Java library, the method I use in this API has the following signature:
void store(InputStream stream, String path, String contentType)
I've managed to make uploads working using the following simple controller:
public static Result uploadFile(String path) {
MultipartFormData body = request().body().asMultipartFormData();
FilePart filePart = body.getFile("files[]");
InputStream is = new FileInputStream(filePart.getFile())
myApi.store(is,path,filePart.getContentType());
return ok();
}
My concern is that this solution is not efficient because by default the play framework stores all the data uploaded by the client in a temporary file on the server then calls my uploadFile() method in the controller.
In a traditional servlet application I would have written a servlet behaving this way:
myApi.store(request.getInputStream(), ...)
I have been searching everywhere and didn't find any solution. The closest example I found is Why makes calling error or done in a BodyParser's Iteratee the request hang in Play Framework 2.0? but I didn't found how to modify it to fit my needs.
Is there a way in play2 to achieve this behavior, i.e. having the data uploaded by the client to go "through" the web-application directly to another system ?
Thanks.
I've been able to stream data to my third-party API using the following Scala controller code:
def uploadFile() =
Action( parse.multipartFormData(myPartHandler) )
{
request => Ok("Done")
}
def myPartHandler: BodyParsers.parse.Multipart.PartHandler[MultipartFormData.FilePart[Result]] = {
parse.Multipart.handleFilePart {
case parse.Multipart.FileInfo(partName, filename, contentType) =>
//Still dirty: the path of the file is in the partName...
String path = partName;
//Set up the PipedOutputStream here, give the input stream to a worker thread
val pos:PipedOutputStream = new PipedOutputStream();
val pis:PipedInputStream = new PipedInputStream(pos);
val worker:UploadFileWorker = new UploadFileWorker(path,pis);
worker.contentType = contentType.get;
worker.start();
//Read content to the POS
Iteratee.fold[Array[Byte], PipedOutputStream](pos) { (os, data) =>
os.write(data)
os
}.mapDone { os =>
os.close()
Ok("upload done")
}
}
}
The UploadFileWorker is a really simple Java class that contains the call to the thrid-party API.
public class UploadFileWorker extends Thread {
String path;
PipedInputStream pis;
public String contentType = "";
public UploadFileWorker(String path, PipedInputStream pis) {
super();
this.path = path;
this.pis = pis;
}
public void run() {
try {
myApi.store(pis, path, contentType);
pis.close();
} catch (Exception ex) {
ex.printStackTrace();
try {pis.close();} catch (Exception ex2) {}
}
}
}
It's not completely perfect because I would have preferred to recover the path as a parameter to the Action but I haven't been able to do so. I thus have added a piece of javascript that updates the name of the input field (and thus the partName) and it does the trick.
I am writing a class in JSP to retrieve a bunch of config values from an XML file. My plan is to have a class "XMLConfig" that loads in the values from the file, and then uses access methods to get at the values in the config object.
My problem is that i cannot seem to call application.getRealPath() from within the class, since eclipse tells me that "application cannot be resolved". I suspect that I must change "application" to something else but I am unsure what.
My code for the class:
<%!
//Config object
public class XMLConfig {
public boolean loadConfigFile(String strName) {
String XMLfileName = application.getRealPath(strName);
try {
DocumentBuilder db = DocumentBuilderFactory.newInstance().newDocumentBuilder();
Document doc = null;
doc = db.parse(XMLFileName);
}catch(Exception e)
{
System.out.println(e.getMessage());
return false;
}
return true;
}
}
%>
application isn't a global var. If you want to use it in your method then you'll need to pass it as a parameter.
Not sure why you're defining the class within the jsp though instead of just creating a 'normal' java class.
That's a job for a servlet instead of JSP. Create a class which extends HttpServlet and implement the doGet() method as follows:
protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
String strName = getOrDefineItSomehow();
Document doc = loadConfigFile(getServletContext().getRealPath(strName));
// Do whatever you want with it and then display JSP page.
request.getRequestDispatcher("/WEB-INF/config.jsp").forward(request, response);
}
Map this servlet in web.xml on an url-pattern of for example /config and invoke it by for example http://example.com/context/config. It'll run the code in doGet().
See also:
Beginning and intermediate JSP/Servlet tutorials
How to avoid Java code in JSP?
Hidden features of JSP/Servlet
I print a list directly in the servlet using the print writer and the list prints.
When I try to put in the jsp however the list doesn't print whether I use JSTL or scriptlets.
I tried to test in JSTL and scriptlet if the object is null and turns out that it is!
Why does this happen and how can I fix this?
Servlet code that works
for (Artist artist:artists){
resp.getWriter().println(artist.getName());
}
Servlet code that puts object in the request
public void doGet(HttpServletRequest req, HttpServletResponse resp)
throws IOException {
ApplicationContext ctx =
new ClassPathXmlApplicationContext("com/helloworld/beans/helloworld-context.xml");
ArtistDao artistDao = (ArtistDao) ctx.getBean("artistDao");
List<Artist> artists = null;
try {
artists = artistDao.getAll();
} catch (SQLException e) {
e.printStackTrace();
}
req.setAttribute("artists", artists);
try {
req.getRequestDispatcher("index.jsp").forward(req, resp);
} catch (ServletException e) {
e.printStackTrace();
}
scriptlet code that suddenly finds the object null
<%
List<Artist> artists = (List<Artist>) request.getAttribute("artists");
if (artists == null) {
out.println("artists null");
}
else {
for (Artist artist: artists){
out.println(artist.getName());
}
}
%>
Even the jstl code seems to agree
<c:if test="${artists eq null}">
Artists are null
</c:if>
<c:forEach var="artist" items="${artists}">
${artist.name}
</c:forEach>
For my app I am using weblogic, spring 2.5.6 and ibatis.
I think it depends on the web server. But without changing your previous directory structure,
try putting the list in session like this
req.getSession(false).setAttribute("artists", artists);
and in your jsp,
write
List<Artist> artists = (List<Artist>) request.getSession(false).getAttribute("artists");
I think my approach will work for all web servers.
Maybe the app server is resetting your request object. You can work around this by creating a new request object, that wraps your original request, and pass that to the reqest dispatcher.
e.g.
MyHttpRequest myRequest = new MyHttpRequest(req);
myRequest.setAttribute(...);
req.getRequestDispatcher("index.jsp").forward(myRequest, resp);
And the MyHttpReqest code:
class MyHttpRequest extends HttpServletRequestWrapper
{
Map attributes = new HashMap();
MyHttpRequest(HttpRequest original) {
super(original);
}
#Override
public void setAttribute(Object key, Object value) {
attributes.put(key, value);
}
public Object getAttribute(Object key) {
Object value = attributes.get(key);
if (value==null)
value = super.getAttribute(key);
return value;
}
// similar for removeAttribute
}
I just discovered inadvertently while trying to fix my directory structure in WebContent/
My previous directory structure was
WEB-CONTENT/
- META-INF/
- WEB-INF/
index.jsp
Then I tried to create a folder jsp in WEB-CONTENT and placed index.jsp there. It works!
My current directory structure now is
WEB-CONTENT/
- META-INF/
- WEB-INF/
- jsp/
-index.jsp
I don't know why it works but it did.
Anyone here with any idea why?
I am writing a simple application that lets a user upload images. After the upload, the user can tag them or remove them.
I figured out how to upload the files and save them once the files are uploaded. I am keeping tracking of a global path where images are kept. In the database I keep the meta data about the images like file name, tags, etc.
I am using Java/JSP (specifically Stripes framework but my problem is generic).
My question is where do I keep these image files once they are uploaded?
Right now I have two web applications deployed on a Tomcat server. One main web application and other one is the where I upload the images.
But this does not work as I can not see the uploaded images in the main application until I redeploy/restart Tomcat.
It seems like Tomcat does not pick newly uploaded images automatically.
Does anyone have any solutions?
This is a simple project, so I do not want to store them in a database or use Apache for images. That is all just too complicated for this small project.
Thanks.
Definitely don't store the images in the database, but you will want to store the image path in the database. This will allow you to store the image just about anywhere.
Since you are using two tomcat applications, your best bet may be to store the images outside of either app and stream the image back to the user instead of letting tomcat manage the files. Otherwise, I would ask why you are trying to do this with two web apps.
However, storing uploaded images inside the web-app directory is not a wise thing to do, and you know it.
By the way, you might want to look this stackoverflow thread, lately discussed where to store the images. It might not solve your issue, surely will give you more confidence on what you are doing.
I've solved this in different ways.
First, the non-portable way, is that Glassfish (and I do believe Tomcat as well) allows you to map an external directory in to the webapps hierarchy. This works really well and does exactly what you want. It lets you store your images in an external directory away from your webapp, yet still serve them up.
However, this technique is not portable.
The way to I've done it portably is by creating a filter.
You place the filter someplace obvious, say "/images".
What the filter does is this:
it checks for the image (or anything, it works with any static resource) in a special directory within the webapp. For our example we'll use the url "/webapp/images".
if the file DOES NOT exist, we copy the file from your external location in to the appropriate spot within the webapp. So, let's say the reqyest url is "/images/banner.gif". And that your files are stored on disk at "/home/app/images". So, our source file is "/home/app/images/banner.gif". We then copy it to where we want it in the webapp tree. We use "ServletContext.getRealPath" for this. So, the destination will be "ServletContext.get RealPath("/webapp/images/banner.gif"). Just copy the source to the destination.
if the file already existed, or now exists, simply forward to the actual image at /webapp/images/banner.gif.
Effectively you end up having a file cache within your webapps deployment tree. The down side is that it's a cache, so it needs to be maintained (i.e. you should check if the original is newer than your cache, make sure you delete if the source is deleted, etc.). Also, it duplicates your resources, so your images will consume, eventually, twice as much disk space. Finally, there's the initial copy cost at start up.
However, it DOES work, and it prevents you from having to serve up static resources using your own code. (Which is the 3rd solution, map a filter/servlet to intercept the URLs and simply stream it your self.)
I would look at the construct within Tomcat (assuming it exists) to do the mapping for you. I know it exists in Glassfish. (Google alternatedocroot for Glassfish to see how it works.)
I was using two web applications to avoid over writing the uploaded images in case I redeploy a new main application war file.
But as you mention there is no other option but to stream them through a Servlet or something I guess I can keep them outside tomcat directory.
I wanted to avoid writing this Streaming Servlet. Just too small project to deal with all the mess (like proper content type, 404, etc.) while writing the streaming servlet.
import java.io.BufferedInputStream;
import java.io.BufferedOutputStream;
import java.io.File;
import java.io.FileInputStream;
import java.io.IOException;
import java.io.PrintWriter;
import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
/**
* Image streaming Servlet.
*/
public class ImageDisplayServlet extends HttpServlet {
private static final long serialVersionUID = 1L;
/**
* #see HttpServlet#HttpServlet()
*/
public ImageDisplayServlet() {
super();
}
/**
* #see HttpServlet#doGet(HttpServletRequest request, HttpServletResponse response)
*/
protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
String relativePath = trimToEmpty(request.getPathInfo());
// Make sure no one try to screw with us.
// This is important as user can literally access any file if we are not careful
if(isXSSAttack(relativePath) == false) {
String pathToFile = this.getServletContext().getRealPath(request.getPathInfo());
File file = new File(pathToFile);
System.out.println("Looking for file " + file.getAbsolutePath());
// show a 404 page
if(!file.exists() || !file.isFile()) {
httpError(404, response);
} else {
try {
streamImageFile(file, response);
} catch(Exception e) {
// Tell the user there was some internal server error.\
// 500 - Internal server error.
httpError(500, response);
e.printStackTrace();
}
}
} else {
// what to do if i think it is a XSS attack ?!?
}
}
private void streamImageFile(File file, HttpServletResponse response) {
// find the right MIME type and set it as content type
response.setContentType(getContentType(file));
BufferedInputStream bis = null;
BufferedOutputStream bos = null;
try {
response.setContentLength((int) file.length());
// Use Buffered Stream for reading/writing.
bis = new BufferedInputStream(new FileInputStream(file));
bos = new BufferedOutputStream(response.getOutputStream());
byte[] buff = new byte[(int) file.length()];
int bytesRead;
// Simple read/write loop.
while (-1 != (bytesRead = bis.read(buff, 0, buff.length))) {
bos.write(buff, 0, bytesRead);
}
} catch (Exception e) {
throw new RuntimeException(e);
} finally {
if (bis != null) {
try {
bis.close();
} catch (IOException e) {
e.printStackTrace();
// To late to do anything about it now, we may have already sent some data to user.
}
}
if (bos != null) {
try {
bos.close();
} catch (IOException e) {
e.printStackTrace();
// To late to do anything about it now, we may have already sent some data to user.
}
}
}
}
private String getContentType(File file) {
if(file.getName().length() > 0) {
String[] parts = file.getName().split("\\.");
if(parts.length > 0) {
// only last part interests me
String extention = parts[parts.length - 1];
if(extention.equalsIgnoreCase("jpg")) {
return "image/jpg";
} else if(extention.equalsIgnoreCase("gif")) {
return "image/gif";
} else if(extention.equalsIgnoreCase("png")) {
return "image/png";
}
}
}
throw new RuntimeException("Can not find content type for the file " + file.getAbsolutePath());
}
private String trimToEmpty(String pathInfo) {
if(pathInfo == null) {
return "";
} else {
return pathInfo.trim();
}
}
private void httpError(int statusCode, HttpServletResponse response) {
try {
response.setStatus(statusCode);
response.setContentType("text/html");
PrintWriter writer = response.getWriter();
writer.append("<html><body><h1>Error Code: " + statusCode + "</h1><body></html>");
writer.flush();
} catch (IOException e) {
e.printStackTrace();
}
}
private boolean isXSSAttack(String path) {
boolean xss = false;
// Split on the bases of know file separator
String[] parts = path.split("/|\\\\");
// Now verify that no part contains anything harmful
for(String part : parts) {
// No double dots ..
// No colons :
// No semicolons ;
if(part.trim().contains("..") || part.trim().contains(":") || part.trim().contains(";")) {
// Fire in the hole!
xss = true;
break;
}
}
return xss;
}
/**
* #see HttpServlet#doPost(Ht/promotions/some.jpgtpServletRequest request, HttpServletResponse response)
*/
protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
doGet(request, response);
}
}
Ok Here is a Servlet that I quickly wrote that can stream images:
Here is the List of limitations and know issues:
May have XSS vulnerability use with care
Not production ready use as reference
Images need to in the web application directory. Can be easily change but I too lazy (it is not worth it the project is too small)
Only stream jpg,gif or png files.
Usage:
Let say you deploy this web application called images as separate application.
http://www.example.com/images/promotions/promo.jpg
means there should be a directory in "promotions" with image "promo.jpg" with in this images web application.
PS: Do not ask why I am doing this Servlet Container only solution that sucks big time.
<servlet>
<description></description>
<display-name>ImageDisplayServlet</display-name>
<servlet-name>ImageDisplayServlet</servlet-name>
<servlet-class>com.example.images.ImageDisplayServlet</servlet-class>
</servlet>
<servlet-mapping>
<servlet-name>ImageDisplayServlet</servlet-name>
<url-pattern>/*</url-pattern>
</servlet-mapping>
Oh ya configure your Servlet like above for best results :P