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Posted to users@tapestry.apache.org by Chris Mylonas <ch...@opencsta.org> on 2012/05/25 03:23:40 UTC
[OT] J2EE write to filesystem & JEE6
Hi Tapestry Users,
In April there was a thread about AssetFactory help [1] and it mentioned that the J2EE spec states that you should not read or write to the file system.
Reading up on the collapsed ear from openejb's website [2] they say (sic) "not quite j2ee but truly jee6".
Although openejb is referencing class loading, where would I find info about whether jee6 allows reading/writing to local filesystem?
It's a handy bad habit I'd like to be able to access - I know it's something I was doing back in early 2000s with tomcat 5 unknowingly being a badass.
Any help would be greatly appreciated,
Chris
[1] = http://tapestry.1045711.n5.nabble.com/File-System-Asset-Factory-help-needed-and-petition-wanted-td5641308.html
[2] = https://openejb.apache.org/collapsed-ear.html
Re: [OT] J2EE write to filesystem & JEE6
Posted by Chris Mylonas <ch...@opencsta.org>.
Very cool - thanks for giving me the reason when it's okay to bend these rules re: Assets not needing transactional business stuff
On 25/05/2012, at 9:43 PM, Geoff Callender wrote:
> Arno is spot on. The spec is being motherly, but in practice if you're uploading assets, as opposed to saving something that must be considered part of a transaction, then there's no harm done in writing to the file system. Everybody does it! Here's an example:
>
> http://jumpstart.doublenegative.com.au/jumpstart/examples/javascript/fileupload
>
> If you're in a clustered environment then just make sure the file is written to a file location that is shared across the cluster.
>
> If the saved files are then to be served up in high volume (eg. lots of images on a page to lots of users) then it may be preferable to return special URLs for them rather than have Tapestry's return them as asset addresses. The special URLs could be detected by Apache (in front of Tapestry) which can then serve them up directly from the file system (rather than have Tapestry stream them).
>
> Of course if there are security requirements (ie. who is allowed to see what files) or the need for a CDN then more is required than I've suggested above.
>
> Geoff
>
> On 25/05/2012, at 6:59 PM, Chris Mylonas wrote:
>
>> 626 pages of spec... and you reply with section number and some copy and paste.
>> I am grateful Arno, thank you!
>>
>>
>> On 25/05/2012, at 5:45 PM, Arno Haase wrote:
>>
>>> -----BEGIN PGP SIGNED MESSAGE-----
>>> Hash: SHA1
>>>
>>> JEE application servers typically do not actually prevent you from
>>> accessing the file system, and the spec does not require them to. So
>>> if it works with your specific app server / jee stack, you are home free.
>>>
>>> The spec prohibits accessing the file system sort of to protect you
>>> from yourseslf - the file system is not transactional, needs attention
>>> in a clustered environment etc.
>>>
>>> That is specified in section 21.2.2 "Programming Restrictions" of the
>>> EJB 3.1 specification (JSR 318,
>>> http://www.oracle.com/technetwork/java/javaee/tech/index.html):
>>>
>>>
>>> •An enterprise bean must not use the java.io package to attempt to
>>> access files and directories in the file system.
>>>
>>> The file system APIs are not well-suited for business components to
>>> access data. Business components should use a resource manager API,
>>> such as JDBC, to store data.
>>>
>>>
>>> The bottom line is:
>>> * the spec allows file system access from a servlet. The restriction
>>> applies only to EJBs.
>>> * Even from EJBs it works and is likely to continue working.
>>> * But accessing the file system from an EJB formally makes an
>>> application not strictly JEE6 compliant.
>>>
>>> I hope that helps
>>>
>>> - - Arno
>>>
>>>
>>> Am 25.05.2012 03:23, schrieb Chris Mylonas:
>>>> Hi Tapestry Users,
>>>>
>>>> In April there was a thread about AssetFactory help [1] and it
>>>> mentioned that the J2EE spec states that you should not read or
>>>> write to the file system. Reading up on the collapsed ear from
>>>> openejb's website [2] they say (sic) "not quite j2ee but truly
>>>> jee6".
>>>>
>>>> Although openejb is referencing class loading, where would I find
>>>> info about whether jee6 allows reading/writing to local
>>>> filesystem? It's a handy bad habit I'd like to be able to access -
>>>> I know it's something I was doing back in early 2000s with tomcat 5
>>>> unknowingly being a badass.
>>>>
>>>> Any help would be greatly appreciated, Chris
>>>>
>>>>
>>>>
>>>> [1] =
>>>> http://tapestry.1045711.n5.nabble.com/File-System-Asset-Factory-help-needed-and-petition-wanted-td5641308.html
>>>>
>>>>
>>> [2] = https://openejb.apache.org/collapsed-ear.html
>>> -----BEGIN PGP SIGNATURE-----
>>> Version: GnuPG v1.4.11 (GNU/Linux)
>>> Comment: Using GnuPG with Mozilla - http://enigmail.mozdev.org/
>>>
>>> iEYEARECAAYFAk+/OIoACgkQbmZsMyUPuXTk5wCgxKl9YZbk1LBdcupOQp1QuABz
>>> zq0AoOBYmu87uYBUgFqr/DqCtdCYBb0M
>>> =VkAE
>>> -----END PGP SIGNATURE-----
>>>
>>> ---------------------------------------------------------------------
>>> To unsubscribe, e-mail: users-unsubscribe@tapestry.apache.org
>>> For additional commands, e-mail: users-help@tapestry.apache.org
>>>
>>
>>
>> ---------------------------------------------------------------------
>> To unsubscribe, e-mail: users-unsubscribe@tapestry.apache.org
>> For additional commands, e-mail: users-help@tapestry.apache.org
>>
>
>
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Re: [OT] J2EE write to filesystem & JEE6
Posted by Geoff Callender <ge...@gmail.com>.
Arno is spot on. The spec is being motherly, but in practice if you're uploading assets, as opposed to saving something that must be considered part of a transaction, then there's no harm done in writing to the file system. Everybody does it! Here's an example:
http://jumpstart.doublenegative.com.au/jumpstart/examples/javascript/fileupload
If you're in a clustered environment then just make sure the file is written to a file location that is shared across the cluster.
If the saved files are then to be served up in high volume (eg. lots of images on a page to lots of users) then it may be preferable to return special URLs for them rather than have Tapestry's return them as asset addresses. The special URLs could be detected by Apache (in front of Tapestry) which can then serve them up directly from the file system (rather than have Tapestry stream them).
Of course if there are security requirements (ie. who is allowed to see what files) or the need for a CDN then more is required than I've suggested above.
Geoff
On 25/05/2012, at 6:59 PM, Chris Mylonas wrote:
> 626 pages of spec... and you reply with section number and some copy and paste.
> I am grateful Arno, thank you!
>
>
> On 25/05/2012, at 5:45 PM, Arno Haase wrote:
>
>> -----BEGIN PGP SIGNED MESSAGE-----
>> Hash: SHA1
>>
>> JEE application servers typically do not actually prevent you from
>> accessing the file system, and the spec does not require them to. So
>> if it works with your specific app server / jee stack, you are home free.
>>
>> The spec prohibits accessing the file system sort of to protect you
>> from yourseslf - the file system is not transactional, needs attention
>> in a clustered environment etc.
>>
>> That is specified in section 21.2.2 "Programming Restrictions" of the
>> EJB 3.1 specification (JSR 318,
>> http://www.oracle.com/technetwork/java/javaee/tech/index.html):
>>
>>
>> •An enterprise bean must not use the java.io package to attempt to
>> access files and directories in the file system.
>>
>> The file system APIs are not well-suited for business components to
>> access data. Business components should use a resource manager API,
>> such as JDBC, to store data.
>>
>>
>> The bottom line is:
>> * the spec allows file system access from a servlet. The restriction
>> applies only to EJBs.
>> * Even from EJBs it works and is likely to continue working.
>> * But accessing the file system from an EJB formally makes an
>> application not strictly JEE6 compliant.
>>
>> I hope that helps
>>
>> - - Arno
>>
>>
>> Am 25.05.2012 03:23, schrieb Chris Mylonas:
>>> Hi Tapestry Users,
>>>
>>> In April there was a thread about AssetFactory help [1] and it
>>> mentioned that the J2EE spec states that you should not read or
>>> write to the file system. Reading up on the collapsed ear from
>>> openejb's website [2] they say (sic) "not quite j2ee but truly
>>> jee6".
>>>
>>> Although openejb is referencing class loading, where would I find
>>> info about whether jee6 allows reading/writing to local
>>> filesystem? It's a handy bad habit I'd like to be able to access -
>>> I know it's something I was doing back in early 2000s with tomcat 5
>>> unknowingly being a badass.
>>>
>>> Any help would be greatly appreciated, Chris
>>>
>>>
>>>
>>> [1] =
>>> http://tapestry.1045711.n5.nabble.com/File-System-Asset-Factory-help-needed-and-petition-wanted-td5641308.html
>>>
>>>
>> [2] = https://openejb.apache.org/collapsed-ear.html
>> -----BEGIN PGP SIGNATURE-----
>> Version: GnuPG v1.4.11 (GNU/Linux)
>> Comment: Using GnuPG with Mozilla - http://enigmail.mozdev.org/
>>
>> iEYEARECAAYFAk+/OIoACgkQbmZsMyUPuXTk5wCgxKl9YZbk1LBdcupOQp1QuABz
>> zq0AoOBYmu87uYBUgFqr/DqCtdCYBb0M
>> =VkAE
>> -----END PGP SIGNATURE-----
>>
>> ---------------------------------------------------------------------
>> To unsubscribe, e-mail: users-unsubscribe@tapestry.apache.org
>> For additional commands, e-mail: users-help@tapestry.apache.org
>>
>
>
> ---------------------------------------------------------------------
> To unsubscribe, e-mail: users-unsubscribe@tapestry.apache.org
> For additional commands, e-mail: users-help@tapestry.apache.org
>
---------------------------------------------------------------------
To unsubscribe, e-mail: users-unsubscribe@tapestry.apache.org
For additional commands, e-mail: users-help@tapestry.apache.org
Re: [OT] J2EE write to filesystem & JEE6
Posted by Chris Mylonas <ch...@opencsta.org>.
626 pages of spec... and you reply with section number and some copy and paste.
I am grateful Arno, thank you!
On 25/05/2012, at 5:45 PM, Arno Haase wrote:
> -----BEGIN PGP SIGNED MESSAGE-----
> Hash: SHA1
>
> JEE application servers typically do not actually prevent you from
> accessing the file system, and the spec does not require them to. So
> if it works with your specific app server / jee stack, you are home free.
>
> The spec prohibits accessing the file system sort of to protect you
> from yourseslf - the file system is not transactional, needs attention
> in a clustered environment etc.
>
> That is specified in section 21.2.2 "Programming Restrictions" of the
> EJB 3.1 specification (JSR 318,
> http://www.oracle.com/technetwork/java/javaee/tech/index.html):
>
>
> •An enterprise bean must not use the java.io package to attempt to
> access files and directories in the file system.
>
> The file system APIs are not well-suited for business components to
> access data. Business components should use a resource manager API,
> such as JDBC, to store data.
>
>
> The bottom line is:
> * the spec allows file system access from a servlet. The restriction
> applies only to EJBs.
> * Even from EJBs it works and is likely to continue working.
> * But accessing the file system from an EJB formally makes an
> application not strictly JEE6 compliant.
>
> I hope that helps
>
> - - Arno
>
>
> Am 25.05.2012 03:23, schrieb Chris Mylonas:
>> Hi Tapestry Users,
>>
>> In April there was a thread about AssetFactory help [1] and it
>> mentioned that the J2EE spec states that you should not read or
>> write to the file system. Reading up on the collapsed ear from
>> openejb's website [2] they say (sic) "not quite j2ee but truly
>> jee6".
>>
>> Although openejb is referencing class loading, where would I find
>> info about whether jee6 allows reading/writing to local
>> filesystem? It's a handy bad habit I'd like to be able to access -
>> I know it's something I was doing back in early 2000s with tomcat 5
>> unknowingly being a badass.
>>
>> Any help would be greatly appreciated, Chris
>>
>>
>>
>> [1] =
>> http://tapestry.1045711.n5.nabble.com/File-System-Asset-Factory-help-needed-and-petition-wanted-td5641308.html
>>
>>
> [2] = https://openejb.apache.org/collapsed-ear.html
> -----BEGIN PGP SIGNATURE-----
> Version: GnuPG v1.4.11 (GNU/Linux)
> Comment: Using GnuPG with Mozilla - http://enigmail.mozdev.org/
>
> iEYEARECAAYFAk+/OIoACgkQbmZsMyUPuXTk5wCgxKl9YZbk1LBdcupOQp1QuABz
> zq0AoOBYmu87uYBUgFqr/DqCtdCYBb0M
> =VkAE
> -----END PGP SIGNATURE-----
>
> ---------------------------------------------------------------------
> To unsubscribe, e-mail: users-unsubscribe@tapestry.apache.org
> For additional commands, e-mail: users-help@tapestry.apache.org
>
---------------------------------------------------------------------
To unsubscribe, e-mail: users-unsubscribe@tapestry.apache.org
For additional commands, e-mail: users-help@tapestry.apache.org
Re: [OT] J2EE write to filesystem & JEE6
Posted by Arno Haase <ar...@haase-consulting.com>.
-----BEGIN PGP SIGNED MESSAGE-----
Hash: SHA1
JEE application servers typically do not actually prevent you from
accessing the file system, and the spec does not require them to. So
if it works with your specific app server / jee stack, you are home free.
The spec prohibits accessing the file system sort of to protect you
from yourseslf - the file system is not transactional, needs attention
in a clustered environment etc.
That is specified in section 21.2.2 "Programming Restrictions" of the
EJB 3.1 specification (JSR 318,
http://www.oracle.com/technetwork/java/javaee/tech/index.html):
•An enterprise bean must not use the java.io package to attempt to
access files and directories in the file system.
The file system APIs are not well-suited for business components to
access data. Business components should use a resource manager API,
such as JDBC, to store data.
The bottom line is:
* the spec allows file system access from a servlet. The restriction
applies only to EJBs.
* Even from EJBs it works and is likely to continue working.
* But accessing the file system from an EJB formally makes an
application not strictly JEE6 compliant.
I hope that helps
- - Arno
Am 25.05.2012 03:23, schrieb Chris Mylonas:
> Hi Tapestry Users,
>
> In April there was a thread about AssetFactory help [1] and it
> mentioned that the J2EE spec states that you should not read or
> write to the file system. Reading up on the collapsed ear from
> openejb's website [2] they say (sic) "not quite j2ee but truly
> jee6".
>
> Although openejb is referencing class loading, where would I find
> info about whether jee6 allows reading/writing to local
> filesystem? It's a handy bad habit I'd like to be able to access -
> I know it's something I was doing back in early 2000s with tomcat 5
> unknowingly being a badass.
>
> Any help would be greatly appreciated, Chris
>
>
>
> [1] =
> http://tapestry.1045711.n5.nabble.com/File-System-Asset-Factory-help-needed-and-petition-wanted-td5641308.html
>
>
[2] = https://openejb.apache.org/collapsed-ear.html
-----BEGIN PGP SIGNATURE-----
Version: GnuPG v1.4.11 (GNU/Linux)
Comment: Using GnuPG with Mozilla - http://enigmail.mozdev.org/
iEYEARECAAYFAk+/OIoACgkQbmZsMyUPuXTk5wCgxKl9YZbk1LBdcupOQp1QuABz
zq0AoOBYmu87uYBUgFqr/DqCtdCYBb0M
=VkAE
-----END PGP SIGNATURE-----
---------------------------------------------------------------------
To unsubscribe, e-mail: users-unsubscribe@tapestry.apache.org
For additional commands, e-mail: users-help@tapestry.apache.org
Re: [OT] J2EE write to filesystem & JEE6
Posted by Chris Mylonas <ch...@opencsta.org>.
To answer my own question (correctly I hope),
This collapsed war (the EJB jars packaged within WAR) thing means for my simple wants, tapestry to pass a URL to a servlet which has access to the filesystem.
It's as simple as that - the servlet is the "gateway" to the filesystem.
Cheers
Chris
On 25/05/2012, at 11:23 AM, Chris Mylonas wrote:
> Hi Tapestry Users,
>
> In April there was a thread about AssetFactory help [1] and it mentioned that the J2EE spec states that you should not read or write to the file system.
> Reading up on the collapsed ear from openejb's website [2] they say (sic) "not quite j2ee but truly jee6".
>
> Although openejb is referencing class loading, where would I find info about whether jee6 allows reading/writing to local filesystem?
> It's a handy bad habit I'd like to be able to access - I know it's something I was doing back in early 2000s with tomcat 5 unknowingly being a badass.
>
> Any help would be greatly appreciated,
> Chris
>
>
>
> [1] = http://tapestry.1045711.n5.nabble.com/File-System-Asset-Factory-help-needed-and-petition-wanted-td5641308.html
> [2] = https://openejb.apache.org/collapsed-ear.html