Re: File exists

[phiroc]

Hi Erik,

my application's SOLR database has a field called "pdf_img", whose value is 
equal to the path of an image which may or may not exist, for all sorts of 
reasons (network issues, etc.)

Before displaying the image with Velocity, I would like to check whether the 
file exists or not, or is accessible or not. If it doesn't exist or it doesn't 
exist, I will display a "image not available" picture.

Philippe



- Mail original -
De: "Erik Hatcher" 
À: "Velocity Users List" 
Envoyé: Jeudi 9 Avril 2015 15:55:18
Objet: Re: File exists

You’re intentionally constrained in Solr to a specific set of helpers, 
otherwise a template could cause a security concern.  See context objects table 
here 
>

If you’re up for some custom Java coding in Solr, you can implement a 
SearchComponent that you can put into any search request handler that would put 
something into the response object, say a boolean that tells you if the file 
exists.  If you need to actually read or write to that file, you could do that 
in the SearchComponent as well.  

Of course the “FileHelper” idea would work if you hacked the 
VelocityResponseWriter code (there is a TODO for me in there to make helpers 
pluggable, but this type of request scares me away from making it too easy! :), 
but the SearchComponent is a way to get custom data into the response which can 
then be leveraged by the Velocity template.  You can also send in custom 
request parameters that become part of the request context object as well, in 
case that helps here.

But I’m curious - what’s the need here?It’s a very unusual request for this 
type of thing, so I’m concerned you’re trying something that should be done a 
different way instead.


—
Erik Hatcher, Senior Solutions Architect
http://www.lucidworks.com 




> On Apr 9, 2015, at 9:18 AM, phi...@free.fr wrote:
> 
> Unfortunately, I am using SOLR's implementation of Velocity, and don't know 
> how to create FileHelpers in that context.
> 
> 
> - Mail original -
> De: "Will Glass-Husain" 
> À: "Velocity Users List" 
> Envoyé: Jeudi 9 Avril 2015 15:06:47
> Objet: Re: File exists
> 
> You can't instantiate objects in Velocity for an arbitrary class.
> remember, Velocity is intended to be a templating, not a scripting
> language.
> 
> Create a new class FileHelper which has a method "fileExists(string)".
> Pass it into the context in your java code as a reference "fileHelper".
> Then in your template call do
> 
> $fileHelper.fileExists("/mnt/etc/etc/etc/")
> 
> WILL
> 
> On Thu, Apr 9, 2015 at 5:58 AM,  wrote:
> 
>> Hello,
>> 
>> does anyone know how to check if a file exists in Velocity?
>> 
>> I have tried:
>> 
>> #set ($exists = new
>> File().exists("/mnt/xxxparnex01_pdf/PDF/IHT/${pdf_year_mon_v}/${pdf_day_v}/${pdf_name_page_number}_${pdf_name_page_type}_VIG.jpg")
>> )
>> 
>> to no avail.
>> 
>> Cheers,
>> 
>> Philippe
>> 
>> -
>> To unsubscribe, e-mail: user-unsubscr...@velocity.apache.org
>> For additional commands, e-mail: user-h...@velocity.apache.org
>> 
>> 
> 
> -
> To unsubscribe, e-mail: user-unsubscr...@velocity.apache.org
> For additional commands, e-mail: user-h...@velocity.apache.org
> 


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Re: File exists

[Erik Hatcher]

You’re intentionally constrained in Solr to a specific set of helpers, 
otherwise a template could cause a security concern.  See context objects table 
here 
>

If you’re up for some custom Java coding in Solr, you can implement a 
SearchComponent that you can put into any search request handler that would put 
something into the response object, say a boolean that tells you if the file 
exists.  If you need to actually read or write to that file, you could do that 
in the SearchComponent as well.  

Of course the “FileHelper” idea would work if you hacked the 
VelocityResponseWriter code (there is a TODO for me in there to make helpers 
pluggable, but this type of request scares me away from making it too easy! :), 
but the SearchComponent is a way to get custom data into the response which can 
then be leveraged by the Velocity template.  You can also send in custom 
request parameters that become part of the request context object as well, in 
case that helps here.

But I’m curious - what’s the need here?It’s a very unusual request for this 
type of thing, so I’m concerned you’re trying something that should be done a 
different way instead.


—
Erik Hatcher, Senior Solutions Architect
http://www.lucidworks.com 




> On Apr 9, 2015, at 9:18 AM, phi...@free.fr wrote:
> 
> Unfortunately, I am using SOLR's implementation of Velocity, and don't know 
> how to create FileHelpers in that context.
> 
> 
> - Mail original -
> De: "Will Glass-Husain" 
> À: "Velocity Users List" 
> Envoyé: Jeudi 9 Avril 2015 15:06:47
> Objet: Re: File exists
> 
> You can't instantiate objects in Velocity for an arbitrary class.
> remember, Velocity is intended to be a templating, not a scripting
> language.
> 
> Create a new class FileHelper which has a method "fileExists(string)".
> Pass it into the context in your java code as a reference "fileHelper".
> Then in your template call do
> 
> $fileHelper.fileExists("/mnt/etc/etc/etc/")
> 
> WILL
> 
> On Thu, Apr 9, 2015 at 5:58 AM,  wrote:
> 
>> Hello,
>> 
>> does anyone know how to check if a file exists in Velocity?
>> 
>> I have tried:
>> 
>> #set ($exists = new
>> File().exists("/mnt/xxxparnex01_pdf/PDF/IHT/${pdf_year_mon_v}/${pdf_day_v}/${pdf_name_page_number}_${pdf_name_page_type}_VIG.jpg")
>> )
>> 
>> to no avail.
>> 
>> Cheers,
>> 
>> Philippe
>> 
>> -
>> To unsubscribe, e-mail: user-unsubscr...@velocity.apache.org
>> For additional commands, e-mail: user-h...@velocity.apache.org
>> 
>> 
> 
> -
> To unsubscribe, e-mail: user-unsubscr...@velocity.apache.org
> For additional commands, e-mail: user-h...@velocity.apache.org
> 

Re: File exists

[phiroc]

Unfortunately, I am using SOLR's implementation of Velocity, and don't know how 
to create FileHelpers in that context.


- Mail original -
De: "Will Glass-Husain" 
À: "Velocity Users List" 
Envoyé: Jeudi 9 Avril 2015 15:06:47
Objet: Re: File exists

You can't instantiate objects in Velocity for an arbitrary class.
 remember, Velocity is intended to be a templating, not a scripting
language.

Create a new class FileHelper which has a method "fileExists(string)".
Pass it into the context in your java code as a reference "fileHelper".
Then in your template call do

$fileHelper.fileExists("/mnt/etc/etc/etc/")

WILL

On Thu, Apr 9, 2015 at 5:58 AM,  wrote:

> Hello,
>
> does anyone know how to check if a file exists in Velocity?
>
> I have tried:
>
> #set ($exists = new
> File().exists("/mnt/xxxparnex01_pdf/PDF/IHT/${pdf_year_mon_v}/${pdf_day_v}/${pdf_name_page_number}_${pdf_name_page_type}_VIG.jpg")
> )
>
> to no avail.
>
> Cheers,
>
> Philippe
>
> -
> To unsubscribe, e-mail: user-unsubscr...@velocity.apache.org
> For additional commands, e-mail: user-h...@velocity.apache.org
>
>

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To unsubscribe, e-mail: user-unsubscr...@velocity.apache.org
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Re: File exists

[Will Glass-Husain]

You can't instantiate objects in Velocity for an arbitrary class.
 remember, Velocity is intended to be a templating, not a scripting
language.

Create a new class FileHelper which has a method "fileExists(string)".
Pass it into the context in your java code as a reference "fileHelper".
Then in your template call do

$fileHelper.fileExists("/mnt/etc/etc/etc/")

WILL

On Thu, Apr 9, 2015 at 5:58 AM,  wrote:

> Hello,
>
> does anyone know how to check if a file exists in Velocity?
>
> I have tried:
>
> #set ($exists = new
> File().exists("/mnt/xxxparnex01_pdf/PDF/IHT/${pdf_year_mon_v}/${pdf_day_v}/${pdf_name_page_number}_${pdf_name_page_type}_VIG.jpg")
> )
>
> to no avail.
>
> Cheers,
>
> Philippe
>
> -
> To unsubscribe, e-mail: user-unsubscr...@velocity.apache.org
> For additional commands, e-mail: user-h...@velocity.apache.org
>
>

File exists

[phiroc]

Hello,

does anyone know how to check if a file exists in Velocity?

I have tried:

#set ($exists = new 
File().exists("/mnt/xxxparnex01_pdf/PDF/IHT/${pdf_year_mon_v}/${pdf_day_v}/${pdf_name_page_number}_${pdf_name_page_type}_VIG.jpg")
 )

to no avail.

Cheers,

Philippe

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