RE: Getting images from Interbase database
His Janusz, I think the problem is that you store your connection in your session. Alle threads are sharing the same session object, and are therefore using the same connection object. Subsequent access (within the same session) to your ImageAction will probably succeed, but concurrent access will fail. As you said, your application gets only few request, so I think that is why the problem did not occur before. (Concurrent requests in the same session will have the same problem) I guess you want to 'cache' your connection to avoid the overhead of creating and openening a connection every time. You should really use a different mechanism to achieve this. Take a look at DBCP (database connection pooling), one of the jakarta-commons components (http://jakarta.apache.org/commons/dbcp/). There is one other thing that can go wrong in your code: You call response.setContentLength(len); after you've written the complete image to your OutputStream. The call to response.setContentLength(len); attempts to send a HTTP header value. If the the response was already flushed to the client, this header will never be sent. The same remark is valid for response.setContentType(image/jpeg); I suggest you to call response.setContentType(image/jpeg); before you stream the binary image. Since you know the size of the retrieved image only after you've read the binary stream, you cannot call response.setContentLength(len) earlier. An alternative might be (if your driver supports it): java.sql.Blob blob = rs.getBlob(1); len = blob.length(); response.setContentLength(len); InputStream is = blob.getBinaryStream(); etc. Good luck, Remke -Oorspronkelijk bericht- Van: Janusz Dziadon [mailto:[EMAIL PROTECTED] Verzonden: dinsdag 16 december 2003 0:37 Aan: [EMAIL PROTECTED] Onderwerp: Getting images from Interbase database Hi all! I am using Struts from about half a year, and it works good. I have small webapp using Interbase database by Interclient driver. When I wanted to use only text data from queries all was fine and simply, even when single jpegs from blob fields. But now I must display some images on one page and I have some errors with doing that. My action classes do their work in normal way - using database connection they get data by ResultSets, transfer them to my java beans, and jsp page is responsible for formatting and displaying this data. But, like I've told it is related only to text data. All pages till now displayed no more than one image from database. To achieve that, on required jsp pages is placed html:img tag with proper properties (ie. image id) which is linked to special action (ImageAction) descendant properly configured in struts.xml file. His work is to: - extract parameters from request (imageid=87) - get one-row ResultSet (rs) with image (select image from images where imageid=87) - gets this image by rs.getBinaryStream(1) - copy this stream to ServletOutputStream - set response mime type and len - send response by closing its output stream (code of this class is attached below) When I need one image on browser page then jsp page contains one tag html:img page=/smallImage.do?imageid=87 /. And all works FINE. SmallImage action simply calls ImageAction. Requests from users goes to server not often. But now I need display html-table with five images and this technique not work. Jsp page contains table tr tdhtml:img page=/smallImage.do?imageid=87 //td tdhtml:img page=/smallImage.do?imageid=88 //td /tr tr tdhtml:img page=/smallImage.do?imageid=89 //td tdhtml:img page=/smallImage.do?imageid=90 //td /tr /table As you see one big change to previous page is that ActionImage class is called four times to fill one page, and this request goes to server almost at once. Errors suggest me, that responsible for this situation goes from ImageAction to Interclient, but I'm not sure. Generally most frequently I get no images, sometimes only one image, but never all four required. All images in database table are in good format, because when I want to get only one image on page they are displayed correctly. So I've started my investigation on How ImageAction doesn't work correctly. I've put into ImageAction class some additional code to write out whats going on. I must say that it looks like action gets four request, starts simultaneously create statements, and gets ResultSets. Problems is when its starts to copy blob stream (place is marked in code). I've get JDBC IOException: Invalid operation to read on closed blob stream. See API reference for exception interbase.interclient.BlobIOEception. All subsequent tries to copy ends with error [interclient] Client/server protocol error: Unexpected token in network message received from Interserver. The internal code is 101. See Api reference for exception interbase.interclient.RemoteProtocolException. Connection to database is
RE: Character Encoding
Hi Stephan, The instruction you use to force UTF-8 looks fine to me, so I don't know why it does not work. This is the way we do it in several web applications too. They are non-public sites, so I am sorry I can not simply let you try them out. Manual transformation should not be necessary. First of all can you make sure that the contenttype header is really sent to the browser? A simple utility that shows you all HTTP requests and response headers (plugin for IE) can be found at: http://www.blunck.info/ieHTTPHeaders.html Also (assuming you are using IE), right-click in your page, move to Encoding and see what is selected there. It should be UTF-8. If you come to the conclusion the response is indeed sent as UTF-8, but still characters are not showing correctly, than I think something is wrong with the source data. Remke -Oorspronkelijk bericht- Van: Stephan Wiesner [mailto:[EMAIL PROTECTED] Verzonden: woensdag 1 oktober 2003 10:10 Aan: Struts Users Mailing List Onderwerp: Character Encoding Hi, I have a web application that needs to support arabic, so I use UTF8 for encoding: %@ page language=java contentType=text/html; charset=UTF-8% This leads to some characters beeing displayed wrong (works fine with Latin-1), like the German 'Ü'. However I can mix them if I write them like '\u05E9' by hand. My text strings come from a database and from my ressource bundles. I could use a Servlet filter to change the Strings before serving them, just have no idea how to transform them? Stephan - To unsubscribe, e-mail: [EMAIL PROTECTED] For additional commands, e-mail: [EMAIL PROTECTED] - To unsubscribe, e-mail: [EMAIL PROTECTED] For additional commands, e-mail: [EMAIL PROTECTED]
RE: Image cache problem
Hi David, I think it has nothing to do with browser versions, I think this is only caused by caching settings. You must realize that caching can occur both in browser cache (configure this using Tools-Internet Options-General-Temporary Internet Files-Settings) and in proxy server cache. You should force your createimage.do to be non cachable. (Instruct proxy servers and browsers to always retrieve a fresh version) You can achieve this by setting a HTTP header: response.setHeader(Cache-Control,no-cache); see the javadocs for more on the setHeader method of the response object. See http://www.mnot.net/cache_docs/ for a very good tutorial on caching. Remke -Oorspronkelijk bericht- Van: David Bolsover [mailto:[EMAIL PROTECTED] Verzonden: donderdag 19 juni 2003 13:51 Aan: Struts User Onderwerp: Image cache problem Hi all I have been using struts for some time now but a new problem has come up: I use a form to select some options needed retrieve some data required to generate a graph. For the sake of clarity, I'll call this retrieveDataAction. retrieveDataAction gets the data and places it into session scope under key 'GRAPHDATA' the user is then forwarded to displaydata.jsp. displaydata.jsp contains the following (simplfied): logic:present name=GRAPHDATA scope=session phtml:img page=/createimage.do //p /logic:present The createimageAction retrieves the GRAPHDATA from session scope, generates a gif image and writes it to response.OutputStream(), closes the stream and returns null. The problem I have is that at least one client (using IE 5) finds that the same image is always presented even though he has requested some different data. I have not been able to reproduce the problem using an IE 6 client - does anyone know if this is an IE 5 'feature' and - is there a solution? David Bolsover - To unsubscribe, e-mail: [EMAIL PROTECTED] For additional commands, e-mail: [EMAIL PROTECTED] - To unsubscribe, e-mail: [EMAIL PROTECTED] For additional commands, e-mail: [EMAIL PROTECTED]
RE: bean:message problems with i18n
Hello Bernard, I agreen with James, that it sounds very much like a caching issue. Could you be behind a caching server without knowing it? (I don't know enough about proxy setups to tell how you could verify this.) Why I think it looks very much like a caching issue, is because you say unvisited pages show up in English, and already visited pages show up in German. Anyway, I think an easy way to check if this is a caching issue or not, is to include a current date (server code of course, not javascript) on your pages. Just try it out on a couple of different pages. By the way, you can avoid caching (both by servers and browsers) by including the following lines first thing in your jsp(s): % response.setHeader(Pragma, No-cache); response.setHeader(Cache-Control, no-cache); response.setDateHeader(Expires, 1); % In our application we are using tiles. I found that it did not work to insert these lines in an inserted tile, they have to be in the top layout file. (Look in the javadocs for the setHeader functions to get a hint why. I don't remember exactly why this was soand I am not even sure I fully understood the reason at the moment I investigated it.) Good luck, Remke Rutgers -Oorspronkelijk bericht- Van: Hirschmann, Bernhard [mailto:[EMAIL PROTECTED]] Verzonden: vrijdag 14 februari 2003 8:18 Aan: 'Struts Users Mailing List' Onderwerp: AW: bean:message problems with i18n Hello all! this is still an open thread for me. It's horrifying... Any help highly appreciated! Regards, Bernhard -Ursprüngliche Nachricht- Von: Hirschmann, Bernhard Gesendet: Donnerstag, 13. Februar 2003 19:15 An: 'Struts Users Mailing List' Betreff: AW: bean:message problems with i18n James, thanks for your help! I tried it in different browser types and in different windows. So this appears also in different HTTPSessions. I can reload as much as I want, and I do not use any proxies for that. So I guess it is not a caching issue. I checked the html:html tag. The lang attribute has always the correct value, like set in the Action.setLocale() method. However, the wrong messages are always in the language, in which the bean:message tag has requested the message the very first time. The fallback mechanism just doesn't work anymore. Does the bean:message tag use some kind of caching using the resources? I also tried to switch back to struts 1.1b2, but with the same result. Bernhard -Ursprüngliche Nachricht- Von: James Childers [mailto:[EMAIL PROTECTED]] Gesendet: Donnerstag, 13. Februar 2003 18:57 An: Struts Users Mailing List Betreff: RE: bean:message problems with i18n Have you tried opening up a new browser and trying again? Sounds like it may be a caching issue. Also, check that your html:html tag is generating the correct lang attribute. Reload the page and view source, then check the HTML tag. -= J -Original Message- From: Hirschmann, Bernhard [mailto:[EMAIL PROTECTED]] Sent: Thursday, February 13, 2003 11:41 AM To: Struts User Mailing List (E-Mail) Subject: bean:message problems with i18n We have big problems with the use of the i18n messages, used with the bean:message tag. But the problems encounter only in a special scenario: 1.) A German user loggs in - a German locale is set using Action.setLocale() - exploring some JSPs, all messages are in German, that's good. 2.) The German user loggs out. 3.) A English user loggs in - a English locale is set using Action.setLocale() - all messages already show in 1.) are still shown in German. But messages from other JSPs not visited in 1.) are shown correctly in English. We use two ApplicationResources: ApplicationResources.properties (the fallback version, in English language) ApplicationResources_de.properties (the German variant) It seems to me, that the mechanism using the ApplicationResources is the reason, but I'm not sure... I debuged through the sources but didn't find the problem. Another strange thing is, that this has worked earlier, but now something must have happend while our further developing processes, so that this 'bug' is appearing. So I tried some older versions of this product we delivered to our customers, and suddenly in those versions is this bug also present. Maybe something on our application server has happend (WS 4.0.4), but I have no clue what this could be... In WSAD 4.0.2 it's the same like in WS 4.0.4. Any hint is highly appretiated. (I'm working on this the whole day now...) - To unsubscribe, e-mail: [EMAIL PROTECTED] For additional commands, e-mail: [EMAIL PROTECTED] - To unsubscribe, e-mail: [EMAIL PROTECTED] For additional commands, e-mail: [EMAIL PROTECTED] - To unsubscribe, e-mail: [EMAIL
RE: Securing a download
Hi Christophe,
This looks very similar to a problem I had (and I bet we are not the only
ones).
Some codes snippets from the RetrieveFileServlet I wrote (a modified version
of code from Wrox 'Professional JSP, 2nd edition').
In your doGet():
// I omitted the exception handling and stream manipulation stuff
String file = request.getParameter(file);
// perform your logic to find out whether the current user may access this
file.
// if not allowed: response.setStatus(HttpServletResponse.SC_FORBIDDEN);
// if allowed continue
String mimetype = null;
if (file != null)
mimetype = getServletContext().getMimeType(file);
if (mimetype != null)
{
// set the content type to the parameter passed.
response.setContentType(mimetype);
}
/*
Store the files in a directory not accessible as a webresource, but
accessible by the useraccount under which your webserver is running.
*/
String basedir = ..; // some directory, hardcodes, properties,
JNDI, whatever
fis = new FileInputStream(basedir+file);
byte[] buffer = new byte[8192];
int size;
size = fis.read(buffer);
while (size != -1)
{
out.write(buffer, 0, size);
size = fis.read(buffer);
}
This should help to handle your security requirements. This lets the browser
determine if the file can be opened in the window (recognized filetypes) or
not.
As for always offering the save as... dialog with the correct filename, you
should be able to achieve that using:
response.addHeader(Content-Disposition, attachment;
filename=+file);
Good luck,
Remke
-Oorspronkelijk bericht-
Van: Christophe Vigouroux [mailto:[EMAIL PROTECTED]]
Verzonden: maandag 23 december 2002 15:37
Aan: 'Struts Users Mailing List'; [EMAIL PROTECTED]
Onderwerp: Securing a download
Hi all,
Here is my problem: I have a user which is granted access to some files to
download. I want to put all the files downloadable by all the users in a
common directory (many users may download the same file), but with the
possibility to deny the download to users not identified by my application
(I've put a bean in the session scope to identify the user).
I first tried to create an Action class taking the filename of the file to
download in parameter, forwarding to the path of my file with a redirect. It
works fine for the first requirement, but it fails to deny the download to
not identified users, because the file is in a public directory. If I try to
put my file directory within WEB-INF, I'm getting the access deny message
from my servlet container (because of the redirect).
Even if my solution does not show the URL to get directly the file (so,
nobody should know the URL), it is not a good one because the security
relies on that hypothesis... I'd prefer to have a servlet or an action or a
jsp which checks the identification of the user, then modifies the HTTP
header with the good mime type (but which one? my files could be .exe, pdf
and so on...), and include the file. But as far as I tried this, my problem
is that my browser give a filename that I don't want (for example I have a
download.do?file=myApp.exe and the browser wants to save download.do where
I wanted it to be myApp.exe.
Hope anybody has a suggestion ;)
Thanks !!
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ConvertUtilts.register(): where to call?
Hi fellowstrutsers, What is the best (logical, efficient, safe...) place to call ConvertUtils.register() in a Struts Webapp? Anyone? Remke Rutgers - [EMAIL PROTECTED] Technisch Consultant Bright Alley Knowledge Learning B.V. Media Park - Sumatralaan 45 Postbus 10 - 1200 JB Hilversum web www.brightalley.com tel +31 35 6774000 / fax +31 35 6774355 -- To unsubscribe, e-mail: mailto:[EMAIL PROTECTED] For additional commands, e-mail: mailto:[EMAIL PROTECTED]
