Serving dynamic JNLP gotchas

I'm planning on providing a means by which users will, upon hitting a certain URL, be served with a JNLP file that is appropriate to their environment. For example, if the user (authenticated in our case via an enhanced version of the MOD_NTLM Apache module) is in a group that should be performing beta testing, he/she could potentially be presented with a JNLP file that enables the testing of the beta version of the application.
There have been many concerns raised on this forum regarding the dynamic generation of JNLP files. One of particular concern to me was: http://forum.java.sun.com/thread.jsp?forum=38&thread=476755 I'm not quite sure, though, which of these issues are truly still issues with the latest 1.4.x of Web Start [1.5 won't be an option for us until it is officially released].
Can anyone provide a summary of the known issues with dynamically serving up JNLP files and their known work-arounds? If there is an FAQ (by Sun or anyone else) that captures these issues, I'd greatly appreciate it if anyone could point me to it.
Also, if you have any advice on which dynamic mechanism (servlet, servlet filter, JSP, other?) seems to work best or cause the least amount of issues, I'd appreciate the feedback.
Thanks in advance,
Mike

You might wonna try to post your questions about serving dynamic JNLP gotchas to the Java Developers group. You can find it online @ http://groups.yahoo.com/group/webstart
- Gerald

Similar Messages

Dynamic JNLP - displaying using java web start

Hi,
I am creating a dynamic JNLP in a servlet at the server side. Please see below.
String someJnlpString = "<?xml version=\"1.0\" encoding=\"UTF-8\"?> \n" +
                                            "<jnlp .....    >    </jnlp>";
        String attachment = "inline; filename=\"launch.jnlp";
        String ct = "application/x-java-jnlp-file";
        OutputStreamWriter out = new OutputStreamWriter(response.getOutputStream());
        response.setContentType(ct);
        response.setHeader("Cache-Control", "max-age=30");
        response.setHeader("Content-disposition", attachment);
        out.write(someJnlpString);{code}
Then in my JSP, I am trying to open this JNLP by using the following code
{code}        window.open('servlet/DisplayImage?arg=first-arg");The exception that I am getting is JNLParseException could not parse launch file. Error at line 0. If I open the downloaded file then its working.
Can somebody please advise me how can I directly open that JNLP from the servlet by using java web start?
Thanks a ton,
Subhash

I am able to run it now after clearing the java cache

Dynamic JNLP and JWS Application Manager

All,
I have a Swing application that communicates to the server via Servlets. I have packaged the entire application into a WAR file and I am using JWS to distribute to the users.
The "main" method of my application accepts two parameters, one of which is dynamic based on information from the web server. To be able to calculate the value of that parameter, I decided to dynamically create and serve my JNLP file through a servlet. The parameter is then passed into the application via the <argument> tag in the served JNLP file.
That part works great. However, once the application is installed, it doesn't show up in JWS Application Manager. My best guess is because there is not a "physical" JNLP file for reference.
Can anyone out there confirm or deny my guess? And, more importantly, can anyone give me an idea on how to keep the dynamic JNLP file and get it to install in the JWS Application Manager?
Thanks!

Got it fixed. Apparently, the JWS Application Manager "view" setting wasn't correct. Once it was working, the application was showing up fine.

Why jws doesn't start when i use jsp as dynamic jnlp?

hello everyone,
i use a jsp as dynamic jnlp to resolve the relative codebase problem,but jws can not start. while i use jnlp, there is no problem.i check the http head the jsp reterned,it seems no problem (it returns "application/x-java-jnlp-file" content type), but jws does not start and the browser opens it as a plan text. below is the http head the jsp and jnlp returned, i can not see any obvious difference that prevent jws start. hope somobody can help me, thanks.
the jsp http head:
HTTP/1.1 200 OK
Content-Type: application/x-java-jnlp-file
Date: Wed, 07 Aug 2002 02:52:31 GMT
Server: Apache Tomcat/4.0.2 (HTTP/1.1 Connector)
Connection: close
Set-Cookie: JSESSIONID=EDAB1A3175B3D319BA33AE090EB973BF;Path=/webims
the jnlp http head:
HTTP/1.1 200 OK
Content-Type: application/x-java-jnlp-file
Content-Length: 372
Date: Wed, 07 Aug 2002 02:49:58 GMT
Server: Apache Tomcat/4.0.2 (HTTP/1.1 Connector)
Connection: close
Last-Modified: Wed, 07 Aug 2002 02:35:19 GMT
ETag: "372-1028687719000"
the response body is same. here is part of the jsp file:
<%@ page contentType="application/x-java-jnlp-file"%>
<%
StringBuffer codebaseBuffer = new StringBuffer();
codebaseBuffer.append(!request.isSecure() ? "http://" : "https://");
codebaseBuffer.append(request.getServerName());
if (request.getServerPort() != (!request.isSecure() ? 80 : 443))
codebaseBuffer.append(':');
codebaseBuffer.append(request.getServerPort());
codebaseBuffer.append(request.getContextPath());
%>
<?xml version="1.0" encoding="UTF-8"?>
<jnlp codebase="<%=codebaseBuffer.toString()%>" href="<%=request.getRequestURI()%>">

I get the same problem since I moved to Tomcat 4.1.18.
The difference is that when I look at a jnlp, I get
Date: Tue, 18 Mar 2003 10:58:25 GMT
Server: Apache/1.3.26 (Unix) mod_jk/1.2.0 mod_ssl/2.8.10 OpenSSL/0.9.6b PHP/4.2.3 FrontPage/5.0.2.2510
Content-Length: 1355
Content-Type: application/x-java-jnlp-file
Last-Modified: Mon, 17 Mar 2003 15:58:46 GMT
Client-Date: Tue, 18 Mar 2003 10:58:25 GMT
Client-Peer: 192.197.110.222:80
and at a jsp:
Date: Tue, 18 Mar 2003 11:06:10 GMT
Server: Apache/1.3.26 (Unix) mod_jk/1.2.0 mod_ssl/2.8.10 OpenSSL/0.9.6b PHP/4.2.3 FrontPage/5.0.2.2510
Content-Type: application/x-java-jnlp-file;charset=ISO-8859-1
Client-Date: Tue, 18 Mar 2003 11:06:10 GMT
Client-Peer: 192.197.110.222:80
Set-Cookie: JSESSIONID=026BF3209EC094A4045F1D37C2A0E98B;Path=/
Could the difference be ;charset=ISO-8859-1
How to remove that, in my jsp I just have :
<% response.setContentType("application/x-java-jnlp-file"); %>
Help
Benoit

Jnlpdownloadservlet and dynamic jnlp file

Problem: we want the version handling (+ jardiff) of JnlpDownLoadServlet, but we also need to construct the jnlp file dynamically (for example: a .jsp file). It seems to me there are two solutions, neither of them good: a) hack the JnlpDownloadServlet (or roll our own), intercepting the jnlp-file-reading code to forward to the jsp page that generates the jnlp xml data and use the generated response as the file contents.
b) generate each jnlp file dynamically and then store it in a temporary location for the JnlpDownloadServlet to pick up. This entails aging the temporary jnlp files and deleting them so the server doesn't get clogged with dead jnlp files.
Is there a third possibility? Or something in the pipe for the near future?
(Note: Web Start Services is not a solution for this task since WSS doesn't support jar versioning, and since the $$properties mechanism does not appear to be ideal for passing a lot of dynamic jnlp information.)
Thanks in advance for any advice.

My jsp page actually generates the list of jars for the application. It also passes some info specific to the user session by means of the jnlp file. Since we are doing games, the list of applications keeps growing. By generating the resource elements dynamically for a game, we can reduce maintenance (as opposed to having a large number of jnlp files with mostly duplicate code) -- especially when a version is updated.
Till we can move to 1.5, I plan to use the temporary file creation method.
Thanks, --John

Dynamic JNLP files?

I have a number of small, embedded devices running a Cherokee web server, each with their own IP address and hostname. Each of these devices has a standard image that includes a few applets. Is there a way to make a standard JNLP file that could go in the image but would still work? My concern is that the codebase is going to be different for device...

A way to generate dynamic JNLP's is by using a servlet.
The servlet path is the JNLP target for the client, and the servlet itself outputs the JNLP contents with the JNLP content-type.
Jacco

How can we take backup of all the RDL'S existing at Report server dynamically at one time

How can we take backup of all the RDL'S existing at Report server dynamically at one time ? I want to take backup of all the reports existing at the report server dynamically at one time only. currently I'm able to take backup of the reports folder wise
using VBScript. and I have to pass the folder names again and again. I want this to be happened for all the reports of all the folders at single shot only using VBScript.

Hi DineshRemash,
Based on my research, we can store the following VB Script to a text file, then modify the file name extension from .txt to .rss.
Dim rootPath As String = "C:\Reports"
Sub Main()
Dim items As CatalogItem() = _
rs.ListChildren("/", true)
For Each item As CatalogItem in items
If item.Type = ItemTypeEnum.Folder Then
CreateDirectory(item.Path)
Else If item.Type = ItemTypeEnum.Report Then
SaveReport(item.Path)
End If
Next
End Sub
Sub CreateDirectory(path As String)
path = GetLocalPath(path)
System.IO.Directory.CreateDirectory(path)
End Sub
Sub SaveReport(reportName As String)
Dim reportDefinition As Byte()
Dim document As New System.Xml.XmlDocument()
reportDefinition = rs.GetReportDefinition(reportName)
Dim stream As New MemoryStream(reportDefinition)
document.Load(stream)
document.Save(GetLocalPath(reportName) + ".rdl")
End Sub
Function GetLocalPath(rsPath As String) As String
Return rootPath + rsPath.Replace("/", "\")
End Function
Then navigate to the folder contains the script, we can directly run the below command from the run menu:
rs -s
http://aa/ ReportServer -i download.rss
We can modify the rootpath to point at whaterver fold you’d like to download the RDL files.
Hope this helps.
Thanks,
Katherine Xiong
Katherine Xiong
TechNet Community Support

How to run the dynamic jnlp generate by jsp, but cache one is not dynamic?

Hi Web Start expert,
I need some urgent help on this issue. I want to pass some session info from my protal web app to my java app through web start. I have tried to use a servlet or jsp to generate a dynamic JNLP which will include all the necessary properties. It works fine if I don't include a href attribute in my jnlp tag. but I won't be able to launch the application off line. So I include the href to point to a static jnlp file resides in the same directory where jars are installed. This time when web start launches, my Java application does not seem to recognize all the login properties I passed through web application, and launch the Login Dialog. What I want to do is, if I come from the portal, since I had signed on to the portal, I don't need to login again to the java app. but when next time I click on the offline shortcut on my desktop for my Java app, I need to sign on to launch my Java app that was cached on the client machine. What is the best way to do this? Please help!
Thanks in advance.
Jenny

The problem here is, when you acess the servlet from the browser, the servlet generates the jnlp file with the properties based on the full reference to the servelt (ie: http://myhost.com/servlet?arguments=xxx;yyy).
If you put the href in the jnlp file:
<jnlp codebase="http://myhost.com" href="servlet">, When Java Web Start is invoked, it will re-download the jnlp file using just "http://myhost.com/servlet", This will cause the servlet to generate jnlp file w/o the propertys that were based on the arguments and parameters to the url.
On the other hand, if you try to add the arguments and parameters to the href wirh <jnlp codebase="http://myhost.com" href="servlet?arguments=xxx;yyy"> two problems occur.
1.) java web start (all versions thru 1.4.2) will generate the cache directory based on the whole string "servlet?arguments=xxx;yyy" this means that every invocation is a seperately cached app, and you will get lots of entries in the download applications page in the Application Manager.
2.) on some platforms, generating cache directory with "?" or ";" can cause IOExceptions.
These problems will be addressed in 1.5:
1 - the cache directory will be based only on the string up to the first "?" or ";".
2 - jnlp files w/o href, will still be shown in the downloaded applications, and can be launched offline (if offline-allowed)
In the mean time the only work around I have heard, is someone tried modifying the servlet, to first download the jnlp file with the correct parameters and args but with href="servlet", but caching the jnlp file generated, and then when java web start requested the servlet with no args, a few seconds later, sending it back the cached version.
/Dietz

Dynamic JNLP causes exception on 1st run after java install

I have a dynamic JNLP file (php) which runs my software. It works just fine, except for the 1st time it is run after a user has installed Java.
I get the exception; "The following field was missing from the jnlp file: <jnlp>". When I look at the jnlp code in JWS in the "Launch File" tab of the error message, I see that the JNLP is not there - but the page the user would see if he was not logged into the system (as if JWS has cached the file or something).
If I close it down, press F5 to refresh, and run it again everything works fine.
I'm running the dyanmic.jnlp?dummy=randomnumber943934 to prevent caching. In addition, these headers are sent: (php code)
header("Last-Modified: " . gmdate("D, d M Y H:i:s") . " GMT");
// HTTP/1.1
header("Cache-Control: no-store, no-cache, must-revalidate");
header("Cache-Control: post-check=0, pre-check=0", false);
// HTTP/1.0
header("Pragma: no-cache");.. so nothing should be cached. But I'm not sure that's where the problem is - cause it only happens the first time after a java install.
Any clues?

I think you're dynamicallt created jnlp is invalid in someway; I can use the following without any problems:
<?php
header("Content-type: application/x-java-jnlp-file");
echo "<?xml version=\"1.0\" ?>\n";
$codebase = trim(stripslashes(urldecode($_REQUEST["codebase"])));
$href = trim(stripslashes(urldecode($_REQUEST["href"])));
echo "<jnlp spec=\"1.0+\" codebase=\"$codebase\" href=\"$href\">\n";
?>
</jnlp>
you should try and test the output of your generated code, something like this should work:
test.php
<html>
<body>
<textarea rows=20 cols=70>
<?php
include 'mydynamicscript.php';
?>
</textarea>
</body>
</html>
The first time a jnlp is called it is downloaded into the browser cache and javaws.exe is executed on it from that location, this in turn downloads the jnlp again from the passed codebase & href attributes into the jws cache. Subsequent calls the jnlp are extracted from the copy in the webstart cache, and often downloaded from the codebase & href attributes when it detects possible changes. In your case these jnlp files seem to differ.
- Richard

Problem of Dynamic JNLP

I pass parameters to jsp with request and use jsp to create jnlp with the parameters.
i use
http://www.exam.com:8001/csec/Start.jsp?name=aaa
to pass name to jnlp
the first time i can get the parameter!
But when the jsp is reloaded,jnlp will lose the parameter,it will be null
i can't slove the problem,
who can help me ,thanks
Start.jsp
outj.println("<?xml version=\"1.0\" encoding=\"utf-8\"?>");
outj.println("<jnlp spec=\"1.0+\" codebase=\"http://www.exam.com:8001/csec"
+ "\"" + " href=\"Start.jsp\">");
String para = request.getParameter("name");
null

Hello Akihabara,
I am contacting you because you had the same issue before.
I am having a Application.jar which has 3 different versions. I have created a version.xml to specify about the version of the application.jar.
Now, I want my user to choose which version he wants to download.
for example: if he has the application_1.1.jar then he should be given a text box (in a JSP page) to enter which version he wants to download. if he enters 1.2 then that particular version should be downloaded.
Normally if we want to use versioning then we specify the the version in the JNLP file (EX: <jar href="application.jar" version="1.2" main="true" download="eager" /> )
I also want the java web start to do "JarDiff" while downloading so that it downloads only the pdated files.
( Normally to implement JarDiff we have to mention the "current-version" field in the jnlp file ( Ex: <jar href="application.jar" version="1.2" main="true" download="eager" current-version="1.1" /> )
I am using JnlpDownloadServlet to process the jnlp file. ( To get dynamic codebase and context path)
Instead of hard-coding the version field and current version fileld in the JNLP file can i generate a dynamic JNLP which would insert the above values for those fields.
In a previous post you solved the similar problem using a servlet as you mentioned over there. Did you use JnlpDownloadServlet also? or You had your own servlet?
Can you guide me regarding this issue.
Thanks,
Anjali

Issue with IE and dynamic JNLP (JSP)

I'm trying to create a JNLP file using JSP to insert a dynamic argument into the webstarted (new word?) program. The link works fine in Firefox and Opera, but IE throws an error and says that it could not download the file. Here's my setup:
JSP file (JNLP)
LaunchClient.jsp
<%@page contentType="application/x-java-jnlp-file"%>
<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE jnlp PUBLIC "-//Sun Microsystems, Inc.//DTD JNLP 1.5//EN" "http://www.netbeans.org/jnlp/DTD/jnlp.dtd">
<%
    String projectRefID = request.getParameter("projectRefID");
%>
<jnlp codebase="http://127.0.0.1:8080/tssa/">
<information>
    <title>AppTest</title>
    <vendor>Company, Inc.</vendor>
    <homepage href="homepage.html"/>
    <description> </description>
    <icon href="default"/>
    <offline-allowed/>
</information>
<resources>
    <j2se href="http://java.sun.com/products/autodl/j2se" version="1.4+"/>
</resources>
<resources>
    <jar download="eager" href="jars/AppTest.jar" main="false"/>
</resources>
<application-desc main-class="apptest.Main">
    <argument><%= projectRefID %></argument>
</application-desc>
</jnlp>My link to the above page looks like this:
<a href="LaunchClient.jsp?projectRefID=<%=currProject.getReferenceIdentifier()%>" >CLICKME</a>I've added the following mime mappings to my web.xml:
    <mime-mapping>
        <extension>jnlp</extension>
        <mime-type>application/x-java-jnlp-file</mime-type>
    </mime-mapping>
    <mime-mapping>
        <extension>jar</extension>
        <mime-type>application/java-archive</mime-type>
    </mime-mapping>I've also tried using a servlet mapping so the link will still have a .jnlp extension as follows:
<servlet>
    <servlet-name>JnlpMapping</servlet-name>
    <jsp-file>/restricted/LaunchClient.jsp</jsp-file>
</servlet>
<servlet-mapping>
    <servlet-name>JnlpMapping</servlet-name>
    <url-pattern>/restricted/myProgram.jnlp</url-pattern>
</servlet-mapping>My link then points to myProgram.jnlp instead of LaunchClient.jsp. But that has the same results (works in firefox/opera but not in IE). Does anyone see why IE is complaining? Do I have to break down and write a servlet?
--Also: I'm using Sun Application Server PE 9
Message was edited by:
QSilver002

I had the same problem. The resolution is preety simple. You can't set header Cache-Control to no-cache, becouse IE tries to cache it before running. That's why any java error occurs, just can't find the file error. What supprised me is that you can't even save the file with right click "Save the target as..", which seems to be little strange. Any other page of type type/html with this header make no problem with that.
Conclusion:
IE makes some special trick with a file of type application/x-java-jnlp-file. Cache-Control to no-cache couses not only disability of running the ws directly, but also saving it locally, which doesn't happen with text/html type of page.
Sevage

How can i access properties from APP server through JNLP with ot using JAR

Hello
i want to retrive a Properties file from WL-7 app installed location like :bea/home/externalized.properties
now i want to use this properties file throgh out the application. if any property is changed in "externalized.properties" that could be reflect dynamically in my code.
So my requirement is :
The current implementaion is using the JNLP down load the required code which contains the properties in .jar files, i have around 500 properties which are embedded in differnet .jar files with differnt property name. So i want to make all 500 properties to get out side from the jar files. and keep that consolidated properties in a single location and access it dynamically after deployed my ear file in wl7 app server.
my application is implemented in SWING and EJB now i want to create an ear file which can be deployed any instance or cluster of WL7 app server.
My Q:
1. How can i access properties file through JNLP? (not a single property, want to access all properties in externalized.properties)
2. is thare any known issue with SUN to load properties file through JNLP?
your help is highly appreciated.
-Siva

Hey Thanks for your response,
My question is Still not answered,
see infact i have different type of environments to launch my application.
infact my weblogic is deployed at remote location whihch is installed in linux,
code is exist in our local system.
At the time of code build for my local system i'm not able to get the properties from remote WL server,
so at the time of code compilation and making the EAR file i'm not having this externalized properties file in newly generated EAR file.
so once i copied my EAR in to WL7 cluster and i'm running the application using startAdminserver.sh, in this script file i'm defining the
java -DexternalizedProperty=$WL_HOME/externalizedProperty.properties so now i'm able to get this properties to 'externalizedProperty"
But when i download my application required jars, at this time i does not having the property file in my downloaded JAR files.
So i want to access the remote properties file in suh sistuation.
now i'm runnig the application at my local side to launch and Server side as well.
So i have 2 runtimes 1 is my local and another is my server. In this case using "-DexternalizedProperty" i'm able to get this in server side,
once control is come to local system it is not able to find this "-DexternalizedProperty" [externalizedProperty].
Hope now u get my scenario..
Thanks,

Dynamic jnlp - automatic launch

I realize there are some posts on this topic, but nothing recent and nothing particularly concrete. Any insight is much appreciated.
I am dynamically building a jnlp so that I can pass dynamic arguments into my webstart app. I am getting the file download dialog that asks me to either open or save my jnlp file. I am running Tomcat 6. I am using https. I have played with various settings based suggesstions in these forums. My response object looks like this:
resp.setHeader("Content-disposition", "attachment; filename=supply.jnlp" );
            resp.setHeader("Cache-Control", null);
            resp.setCharacterEncoding(null);
            resp.setHeader("Set-Cookie", null);
            resp.setHeader("Vary", null);
            resp.setDateHeader("Last-Modified", new Date().getTime()); my web.xml looks like this:
<servlet>
     <servlet-name>SupplyJNLPServlet</servlet-name>
     <servlet-class>mil.atc.supply.servlet.SupplyJnlpBuilderServlet</servlet-class>
</servlet>
<servlet-mapping>
     <servlet-name>SupplyJNLPServlet</servlet-name>
     <url-pattern>/SupplyJNLP</url-pattern>
</servlet-mapping>
<servlet>
     <servlet-name>JnlpDownloadServlet</servlet-name>
     <display-name>JnlpDownloadServlet</display-name>
     <servlet-class>jnlp.sample.servlet.JnlpDownloadServlet</servlet-class>
</servlet>
<servlet-mapping>
     <servlet-name>JnlpDownloadServlet</servlet-name>
     <url-pattern>*.jnlp</url-pattern>
</servlet-mapping>
<mime-mapping>
     <extension>jnlp</extension>
     <mime-type>application/x-java-jnlp-file</mime-type>
</mime-mapping>
The jnlp mime type is configured on my IIS server - I am using the Apache ASAPI filters.
Once again, thanks for any help.

dcfrank65, or anyone else... did you ever discover a solution to this problem?
I too have an issue whereby opening a dynamically generated jnlp file over HTTP works fine, but opening it over HTTPS causes IE to prompt whether the file should be opened or saved. As you already discovered, there do seem to be quite a few threads covering this topic, but none with a definitive answer. In my case, the JNLP file is being rendered by ASP.NET code running on IIS.
For the record, at the risk of becoming immediately unpopular (!), AndrewThompson64's comment about how dcrank65 failed to ask a question seems unnecessarily obtuse, since dcfrank65 did previous say:
"I don't want to be prompted to open or save, I want my jnlp file to be executed and the webstart application to run with no further action from my user. +So I am asking for ideas to accomplish this+."
This is a fairly clear and concise request for information, regardless of whether it was phrased as a question. So, dcfrank's response, though a little strong, seems justified.

Flash Media Server dynamic Livestreaming

I have FMS 3.5 installed, everything is running. I want to have a livestream from a camera that is dynamic and will change according to the bandwith of the viewer. What settings do I need to choose in Flash Media Encoder, FMS and in the Player to make this possible? If I start the encoder with 3 videostreams and a %i parameter I get 3 different streams, but I can only put one of these in a player and not all. What do I need to do?

In essence each client does a bandwidth test as it connects and the chooses the most suitable stream for that connection. This is described in the docs that came with the server...look here;
http://help.adobe.com/en_US/FlashMediaServer/3.5_Deving/WS5b3ccc516d4fbf351e63e3d11a0773d5 6e-7fea.html

Setting Up the File Server Dynamically

I have a scenario wherin i have to set up the FTP server name and directory where i have to put the final file dymically.
I was able to set the directory path dynamically using Adapter Specific Message properties.
Can somebody suggest me if i can set the server name also by module processor (have not written one till now)or some other way. The steps to follow etc
Waiting for your useful answers.

Hi Siva,
Setting up a Server name Dynamically -I don't think so it is possible with this point of time.
So try to do in Java Proxy if required.
Receiver File Adapter - Dynamic FTP Server Address
Hope this helps,
Regards,
Moorthy

Serving dynamic JNLP gotchas

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