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Posted to users@tomcat.apache.org by James Finnall <Ja...@Finnall.net> on 2018/07/17 14:19:43 UTC
best practice for temporary file
Hello all,
What is the best practice under Tomcat to create a data file and then
allow the client to download it?
So far all my attempts have failed. If the Java app can write it then
the client can not download, if client can download then the Java app
can not write it.
Does Tomcat have a provision to create a directory that be shared by
both the app and the client?
Thank you for your consideration,
James
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Re: best practice for temporary file
Posted by Christopher Schultz <ch...@christopherschultz.net>.
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Chris,
On 7/17/18 10:36 AM, Chris Cheshire wrote:
> James, this can be done using something like the following
> configuration in your META-INF/context.xml (I use tomcat 8.5)
>
> <Resources> <PreResources
> className="org.apache.catalina.webresources.DirResourceSet"
> base="${catalina.base}/cdn/ROOT/images" webAppMount="/images" />
> </Resources>
>
> I use this to serve files at /images because they are dynamic
> content and not part of the war itself. Make sure the directory
> specified by "base" has read and write permission by the tomcat
> user at the OS level and then you can serve files with a uri
> starting with /images/.
Just be careful about doing this kind of thing because Tomcat will
cache resources it finds there, or at least the metadata about those
files. So if you get a cache miss on a file that doesn't exist, Tomcat
may "remember" that the resource doesn't exist when you write a file
to that directory and then the cache will be stale.
You must arrange for the first access of the file by the client to
occur after the file has been written to the disk, otherwise you risk
these kinds of problems.
Also, things can get weird when the file is subsequently removed.
Just be careful.
- -chris
> On Tue, Jul 17, 2018 at 10:21 AM James Finnall <Ja...@finnall.net>
> wrote:
>>
>> Hello all,
>>
>> What is the best practice under Tomcat to create a data file and
>> then allow the client to download it?
>>
>> So far all my attempts have failed. If the Java app can write it
>> then the client can not download, if client can download then the
>> Java app can not write it.
>>
>> Does Tomcat have a provision to create a directory that be shared
>> by both the app and the client?
>>
>>
>> Thank you for your consideration, James
>>
>>
>> ---------------------------------------------------------------------
>>
>>
To unsubscribe, e-mail: users-unsubscribe@tomcat.apache.org
>> For additional commands, e-mail: users-help@tomcat.apache.org
>>
>
> ---------------------------------------------------------------------
>
>
To unsubscribe, e-mail: users-unsubscribe@tomcat.apache.org
> For additional commands, e-mail: users-help@tomcat.apache.org
>
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Re: best practice for temporary file
Posted by James Finnall <Ja...@Finnall.net>.
Thank you!
Had some problems but I was able to research the issues and find a
solution to what I was doing wrong. I did not have a "/cdn/ROOT"
directory, mine is "/webapps/ROOT". The Resource section needs to be
with-in the Context section and not after it. My original context.xml
file only had two lines. I had to use two different file paths, since
the application path (/opt/tomcat/..." is different from the client
path (/temp/...).
Once I had the issues corrected it worked great. Thank you, again.
James
On Tue, 2018-07-17 at 10:36 -0400, Chris Cheshire wrote:
>
> James, this can be done using something like the following
> configuration in your META-INF/context.xml (I use tomcat 8.5)
>
> <Resources>
> <PreResources
> className="org.apache.catalina.webresources.DirResourceSet"
> base="${catalina.base}/cdn/ROOT/images"
> webAppMount="/images" />
> </Resources>
>
> I use this to serve files at /images because they are dynamic content
> and not part of the war itself. Make sure the directory specified by
> "base" has read and write permission by the tomcat user at the OS
> level and then you can serve files with a uri starting with /images/.
>
> HTH
>
> Chris
>
> On Tue, Jul 17, 2018 at 10:21 AM James Finnall <Ja...@finnall.net>
> wrote:
> >
> >
> >
> > Hello all,
> >
> > What is the best practice under Tomcat to create a data file and
> > then
> > allow the client to download it?
> >
> > So far all my attempts have failed. If the Java app can write it
> > then
> > the client can not download, if client can download then the Java
> > app
> > can not write it.
> >
> > Does Tomcat have a provision to create a directory that be shared
> > by
> > both the app and the client?
> >
> >
> > Thank you for your consideration,
> > James
> >
> >
> > -----------------------------------------------------------------
> > ----
> > To unsubscribe, e-mail: users-unsubscribe@tomcat.apache.org
> > For additional commands, e-mail: users-help@tomcat.apache.org
> >
> ---------------------------------------------------------------------
> To unsubscribe, e-mail: users-unsubscribe@tomcat.apache.org
> For additional commands, e-mail: users-help@tomcat.apache.org
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Re: best practice for temporary file
Posted by Chris Cheshire <ya...@gmail.com>.
James, this can be done using something like the following
configuration in your META-INF/context.xml (I use tomcat 8.5)
<Resources>
<PreResources className="org.apache.catalina.webresources.DirResourceSet"
base="${catalina.base}/cdn/ROOT/images"
webAppMount="/images" />
</Resources>
I use this to serve files at /images because they are dynamic content
and not part of the war itself. Make sure the directory specified by
"base" has read and write permission by the tomcat user at the OS
level and then you can serve files with a uri starting with /images/.
HTH
Chris
On Tue, Jul 17, 2018 at 10:21 AM James Finnall <Ja...@finnall.net> wrote:
>
> Hello all,
>
> What is the best practice under Tomcat to create a data file and then
> allow the client to download it?
>
> So far all my attempts have failed. If the Java app can write it then
> the client can not download, if client can download then the Java app
> can not write it.
>
> Does Tomcat have a provision to create a directory that be shared by
> both the app and the client?
>
>
> Thank you for your consideration,
> James
>
>
> ---------------------------------------------------------------------
> To unsubscribe, e-mail: users-unsubscribe@tomcat.apache.org
> For additional commands, e-mail: users-help@tomcat.apache.org
>
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