Re: Writing files accessible from a browser

[Romain Quilici]

Hi,
Hope I will be clear enough:

One part of my web application receives encodes stream that it has to 
convert to jpg images. When an image is written on the server, it 
notifies a Servlet  which pushes the  name (or the url) of the newly 
generated image inside client browser(thanks to pushlets  technology).
The Servlet can only push a String (Pushlets requirements).
So my problem is where can I write the images, so they can be accessible 
by a URL. One easy solution, the one I use for testing, is to hardcode 
in my webapp the directory where the images are written.
For instance TOMCAT_HOME\webapps\frames\,
and in my jsp to have <img src="http://myserver/frames/name.jpg> where 
name.jpg is pushed by the servlet when this image is generated.

However, this solution is not satisfactory, indeed, if I deploy my 
application in another place, I don't want people to edit my code to 
change for suitable values. I admit I could use properties or a 
configuration file to set these value(even if I am not sure it would 
work in all configuration), anyway I would like to check if using the 
servletcontext, or other solutions might be more appropriate.
As I said a solution with the temp directory would be perfect, if this 
directory was accessible with a URL

Hope it is clear
Regards
Li wrote:
Hi,

It is not advisable to make your webapp dir writable, can you tell me
what exactly would you like to achieve so that I may get more info to
help out ...



On 8/7/06, Romain Quilici <[EMAIL PROTECTED]> wrote:
Hi,
thanks for the advice,
But I want to avoid harcoded links such as $APACHE_HOME\httpdocs\images
or <a href="http://yourdomain/images/1.jpg";> in my jsp.

Indeed I don't want to modify these values if I decide Tomcat to run on
another port, or to install Tomcat in another directory or even OS. That
is why I am looking for an approach using
the webapp context, so I don't have to worry about the OS, or the port,
or whatever configuration.
Anyway thanks for your help
Regards
Romain

Li wrote:
> Hi,
>
> Here are few steps of achieving it (just tested, and it works):
> 1. use FileOutputStream or any output streaming object to write a
> image file
>    into the directory
>   in Windows, the path string should look like:
> "c:\apache_home\httpdocs\images\1.jpg"
>   in unix/linux, the path should look like
> $APACHE_HOME\httpdocs\images\1.jpg"
>   (assume, you had defined APACHE_HOME, make sure the images folder
> is read/write
>   only for the user/group that runs tomcat
> 2. Make sure apache is on ...
> 3. in your jsp: use
>   e.g. <a href="http://yourdomain/images/1.jpg";>click to view</a>
>
>
> Wish it helps
>
> On 8/7/06, Romain Quilici <[EMAIL PROTECTED]> wrote:
>> Thanks for the answer,
>> this solution was part of my investigation, and was actually the 
first
>> idea I had.
>> The problem with this approach is I don't know how to access the
>> /image_dir/ from within my web application.
>> Maybe using something like
>> String path = servletContext.getRealPath("/");
>> String imagePath = path+"../image_dir/"
>> and use the imagePath to create my images, then in my jsp 
something like
>> <request.getContextPath()/../image_dir/image1.jpg>
>>
>> But I am not sure this approach works in all configurations,
>> particularly if my webapp is deployed inside a war.
>>
>> Thanks
>> Romain
>>
>> Li wrote:
>> > if you have apache server, you can write file to its home dir, and
>> > then use
>> > http://<youdomain>/<image_dir>/image_name.suffix to view.
>> >
>> > On 8/7/06, Romain Quilici <[EMAIL PROTECTED]> wrote:
>> >> Hi all,
>> >> I have been reading several messages about writing files inside 
a web
>> >> application, but I found no answer regarding my problem.
>> >>
>> >> I need to write files on the file system that can be accessible
>> with a
>> >> browser(I write images).
>> >>
>> >> - The most reliable solution I found was to use the webapp's tmp
>> >> directory, unfortunately this directory is not accessible with 
a URL.
>> >>
>> >> - Another solution would be to write these images under my webapp
>> >> root(or in another place under my webapp). But it seems that this
>> >> approach does not work with webapps deployed in a war file.
>> >> Indeed you cannot write inside wars like this.
>> >>
>> >> I don't want to rely on some hardcoded solutions. There is 
still the
>> >> possibility to pass the absolute path to the directory (let's say
>> >> TOMCAT_HOME/webapps/myimages/) and later, use inside my JSP
>> >> <request.getContextPath()/../myimages/image1.jpg>, but I think 
this
>> >> solution won't work in many configurations
>> >>
>> >> Thanks a lot for your help
>> >> Regards
>> >> Romain
>> >>
>> >>
>> >>
>> >>
>> >> 
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>> >>
>> >
>> >
>>
>>
>>
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>
>



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