17 Dec
2012
17 Dec
'12
6:31 p.m.
Hello XWiki experts,
I'm implementing OAI-PMH, a service infrastructure to aggregate digital library
items.
I do so with a few velocity pages and a groovy page. I'll happily share it.
At first, I did not implement the "resumption" flow-control, which allows a big
search list to be paged in several requests as I expected the output of my velocity script
to trigger a buffer-full and start delivering the packets down the line.
But this fails, nothing comes before it's finished.
And indeed, I receive a content-length header... so there is buffering happening
somewhere.
Do I have a possibility to disable velocity output buffering?
Paul
19 Dec
19 Dec
7:07 p.m.
On 12/17/2012 12:31 PM, Paul Libbrecht wrote:
Hello XWiki experts,
I'm implementing OAI-PMH, a service infrastructure to aggregate digital library
items.
I do so with a few velocity pages and a groovy page. I'll happily share it.
At first, I did not implement the "resumption" flow-control, which allows a
big search list to be paged in several requests as I expected the output of my velocity
script to trigger a buffer-full and start delivering the packets down the line.
But this fails, nothing comes before it's finished.
And indeed, I receive a content-length header... so there is buffering happening
somewhere.
Do I have a possibility to disable velocity output buffering?
It's not Velocity that's buffering, it's the whole rendering engine that
does that. Velocity itself is just one of the steps through which
document content passes, and each step outputs everything in a buffer
which is later flushed down the socket after every rendering step is
finished.
At least that's what's happening if you use the rendering engine to
"run" code from wiki documents.
--
Sergiu Dumitriu
http://purl.org/net/sergiu
7:33 p.m.
It's not Velocity that's buffering, it's
the whole rendering engine that
does that. Velocity itself is just one of the steps through which
document content passes, and each step outputs everything in a buffer
which is later flushed down the socket after every rendering step is
finished.
At least that's what's happening if you use the rendering engine to
"run" code from wiki documents.
Is there any way to disable buffering at each of the steps?
I'm thinking this may have a performance impact.
However, for my case, implementing OAI-PMH, I've solved it by using the "query
resumption" that the protocol offers.
paul
7:38 p.m.
On 12/19/2012 01:33 PM, Paul Libbrecht wrote:
No, especially not with the current (XRendering) rendering engine, since
Velocity is just a Transformation that works on the XDOM, which will be
actually transformed into real output in a separate process that expects
a final, full DOM.
It's not
Velocity that's buffering, it's the whole rendering engine that
does that. Velocity itself is just one of the steps through which
document content passes, and each step outputs everything in a buffer
which is later flushed down the socket after every rendering step is
finished.
At least that's what's happening if you use the rendering engine to
"run" code from wiki documents.
Is there any way to disable buffering at each of the steps? I'm thinking this may have a performance impact.
Yes, it does.
However, for my case, implementing OAI-PMH, I've
solved it by using the "query resumption" that the protocol offers.
It's good that you found a workaround.
--
Sergiu Dumitriu
http://purl.org/net/sergiu
20 Dec
20 Dec
10:47 a.m.
On Wed, Dec 19, 2012 at 7:38 PM, Sergiu Dumitriu <sergiu(a)xwiki.org> wrote:
--
Thomas Mortagne
On 12/19/2012 01:33 PM, Paul Libbrecht wrote:
No, especially not with the current (XRendering) rendering engine, since
Velocity is just a Transformation that works on the XDOM, which will be
actually transformed into real output in a separate process that expects
a final, full DOM.
That's true but it does not prevent you to write directly in the response
if you want.
Something like:
## Get the response buffer/stream
#set($out = $response.outputStream())
## Write some content to the response buffer
$out.print("some content")
## Make sure everything is sent
$out.flush()
## Indicate XWiki that you already sent the answer
$xcontext.setFinished(true)
It's
not Velocity that's buffering, it's the whole rendering engine that
does that. Velocity itself is just one of the steps through which
document content passes, and each step outputs everything in a buffer
which is later flushed down the socket after every rendering step is
finished.
At least that's what's happening if you use the rendering engine to
"run" code from wiki documents.
Is there any way to disable buffering at each of the steps? I'm
thinking this may have a performance impact.
Yes, it does.
However, for my case, implementing OAI-PMH,
I've solved it by using the
"query resumption" that the protocol
offers.
It's good that you found a workaround.
--
Sergiu Dumitriu
http://purl.org/net/sergiu
_______________________________________________
users mailing list
users(a)xwiki.org
http://lists.xwiki.org/mailman/listinfo/users
11 a.m.
That's true but it does not prevent you to write directly in the response
if you want.
Something like:
## Get the response buffer/stream
#set($out = $response.outputStream())
## Write some content to the response buffer
$out.print("some content")
## Make sure everything is sent
$out.flush()
## Indicate XWiki that you already sent the answer
$xcontext.setFinished(true)
Hey, we're getting closer!
How does this play with the velocity execution? Would its output be discarded then?
I've tried this:
$response.setContentType("text/plain")##
#set($out = $response.outputStream())##
## Write some content to the response buffer
$out.println("some content")##
$out.println("some content")##
$out.println("some content")##
$out.println("some content")##
$out.println("some content")##
$out.println("some content")##
$out.println("some content")##
$out.println("some content")##
$out.println("some content")##
$out.println("some content")
## Make sure everything is sent
$out.flush()##
## Indicate XWiki that you already sent the answer
$xcontext.setFinished(true)##
and had only blank pages/
Paul
noon
On Thu, Dec 20, 2012 at 11:00 AM, Paul Libbrecht <paul(a)hoplahup.net> wrote:
That's because you did not really wrote anything ;)
I made a mistake in my example, it's
#set($out = $response.outputStream)
without the parentheses.
That's true but it does not prevent you to write directly in the response
if you want.
Something like:
## Get the response buffer/stream
#set($out = $response.outputStream())
## Write some content to the response buffer
$out.print("some content")
## Make sure everything is sent
$out.flush()
## Indicate XWiki that you already sent the answer
$xcontext.setFinished(true)
Hey, we're getting closer!
How does this play with the velocity execution? Would its output be
discarded then?
I've tried this:
$response.setContentType("text/plain")##
#set($out = $response.outputStream())##
## Write some content to the response buffer
$out.println("some content")##
$out.println("some content")##
$out.println("some content")##
$out.println("some content")##
$out.println("some content")##
$out.println("some content")##
$out.println("some content")##
$out.println("some content")##
$out.println("some content")##
$out.println("some content")
## Make sure everything is sent
$out.flush()##
## Indicate XWiki that you already sent the answer
$xcontext.setFinished(true)##
and had only blank pages/
Paul
_______________________________________________
users mailing list
users(a)xwiki.org
http://lists.xwiki.org/mailman/listinfo/users
--
Thomas Mortagne
12:46 p.m.
great, that worked.
However, it means the velocity output is forgotten so I'd have to call velocity at
places where it makes sense.
I'm also caught by this kind of things, the "eat all exceptions" type of
approach of velocity is not a charm!
It's good to know as a strategy for the future.
paul
Le 20 déc. 2012 à 12:00, Thomas Mortagne a écrit :
On Thu, Dec 20, 2012 at 11:00 AM, Paul Libbrecht
<paul(a)hoplahup.net> wrote:
That's because you did not really wrote anything ;)
I made a mistake in my example, it's
#set($out = $response.outputStream)
without the parentheses.
That's true but it does not prevent you to write directly in the response
if you want.
Something like:
## Get the response buffer/stream
#set($out = $response.outputStream())
## Write some content to the response buffer
$out.print("some content")
## Make sure everything is sent
$out.flush()
## Indicate XWiki that you already sent the answer
$xcontext.setFinished(true)
Hey, we're getting closer!
How does this play with the velocity execution? Would its output be
discarded then?
I've tried this:
$response.setContentType("text/plain")##
#set($out = $response.outputStream())##
## Write some content to the response buffer
$out.println("some content")##
$out.println("some content")##
$out.println("some content")##
$out.println("some content")##
$out.println("some content")##
$out.println("some content")##
$out.println("some content")##
$out.println("some content")##
$out.println("some content")##
$out.println("some content")
## Make sure everything is sent
$out.flush()##
## Indicate XWiki that you already sent the answer
$xcontext.setFinished(true)##
and had only blank pages/
Paul
_______________________________________________
users mailing list
users(a)xwiki.org
http://lists.xwiki.org/mailman/listinfo/users
--
Thomas Mortagne
_______________________________________________
users mailing list
users(a)xwiki.org
http://lists.xwiki.org/mailman/listinfo/users
21 Dec
21 Dec
4:39 p.m.
Thomas, all,
would I have a way to invoke velocity using the scope being run but without the
rendering?
I guess that would be the exact use case here and it is likely to be so for other people;
for example to generate xml documents, json documents...
thanks in advance.
paul
Le 20 déc. 2012 à 12:46, Paul Libbrecht a écrit :
great, that worked.
However, it means the velocity output is forgotten so I'd have to call velocity at
places where it makes sense.
I'm also caught by this kind of things, the "eat all exceptions" type of
approach of velocity is not a charm!
It's good to know as a strategy for the future.
paul
Le 20 déc. 2012 à 12:00, Thomas Mortagne a écrit :
On Thu, Dec 20, 2012 at 11:00 AM, Paul Libbrecht
<paul(a)hoplahup.net> wrote:
That's because you did not really wrote anything ;)
I made a mistake in my example, it's
#set($out = $response.outputStream)
without the parentheses.
_______________________________________________
users mailing list
users(a)xwiki.org
http://lists.xwiki.org/mailman/listinfo/users
That's true but it does not prevent you to write directly in the response
if you want.
Something like:
## Get the response buffer/stream
#set($out = $response.outputStream())
## Write some content to the response buffer
$out.print("some content")
## Make sure everything is sent
$out.flush()
## Indicate XWiki that you already sent the answer
$xcontext.setFinished(true)
Hey, we're getting closer!
How does this play with the velocity execution? Would its output be
discarded then?
I've tried this:
$response.setContentType("text/plain")##
#set($out = $response.outputStream())##
## Write some content to the response buffer
$out.println("some content")##
$out.println("some content")##
$out.println("some content")##
$out.println("some content")##
$out.println("some content")##
$out.println("some content")##
$out.println("some content")##
$out.println("some content")##
$out.println("some content")##
$out.println("some content")
## Make sure everything is sent
$out.flush()##
## Indicate XWiki that you already sent the answer
$xcontext.setFinished(true)##
and had only blank pages/
Paul
_______________________________________________
users mailing list
users(a)xwiki.org
http://lists.xwiki.org/mailman/listinfo/users
--
Thomas Mortagne
_______________________________________________
users mailing list
users(a)xwiki.org
http://lists.xwiki.org/mailman/listinfo/users
4:50 p.m.
On 12/21/2012 10:39 AM, Paul Libbrecht wrote:
Thomas, all,
would I have a way to invoke velocity using the scope being run but without the
rendering?
I guess that would be the exact use case here and it is likely to be so for other people;
for example to generate xml documents, json documents...
thanks in advance.
It is possible, but not with what's available out of the box. You would
have to write a new action that is only responsible for invoking
Velocity, connecting its output directly to the socket.
--
Sergiu Dumitriu
http://purl.org/net/sergiu/
5:11 p.m.
would I have a
way to invoke velocity using the scope being run but without the rendering?
I guess that would be the exact use case here and it is likely to be so for other people;
for example to generate xml documents, json documents...
It is possible, but not with what's available out of the box. You would
have to write a new action that is only responsible for invoking
Velocity, connecting its output directly to the socket.
5:16 p.m.
On Fri, Dec 21, 2012 at 4:39 PM, Paul Libbrecht <paul(a)hoplahup.net> wrote:
Thomas, all,
would I have a way to invoke velocity using the scope being run but
without the rendering?
I guess that would be the exact use case here and it is likely to be so
for other people; for example to generate xml documents, json documents...
Not sure I fully undertand what you ask, when you use
$xcontext.setFinished(true) you will get only when you wrote directly to
the output stream. I'm using it to generate translation packages in
l10n.xwiki.org for example.
thanks in advance.
paul
Le 20 déc. 2012 à 12:46, Paul Libbrecht a écrit :
_______________________________________________
users mailing list
users(a)xwiki.org
http://lists.xwiki.org/mailman/listinfo/users
_______________________________________________
users mailing list
users(a)xwiki.org
http://lists.xwiki.org/mailman/listinfo/users
--
Thomas Mortagne
great, that worked.
However, it means the velocity output is forgotten so I'd have to call
velocity at places where it makes sense.
I'm also caught by this kind of things, the "eat all exceptions" type of
approach of velocity is not a charm!
It's good to know as a strategy for the future.
paul
Le 20 déc. 2012 à 12:00, Thomas Mortagne a écrit :
> On Thu, Dec 20, 2012 at 11:00 AM, Paul Libbrecht <paul(a)hoplahup.net>
wrote:
>
>>>
>>> That's true but it does not prevent you to write directly in the
response
> if you want.
>
> Something like:
>
> ## Get the response buffer/stream
> #set($out = $response.outputStream())
>
> ## Write some content to the response buffer
> $out.print("some content")
>
> ## Make sure everything is sent
> $out.flush()
>
> ## Indicate XWiki that you already sent the answer
> $xcontext.setFinished(true)
Hey, we're getting closer!
How does this play with the velocity execution? Would its output be
discarded then?
I've tried this:
$response.setContentType("text/plain")##
#set($out = $response.outputStream())##
## Write some content to the response buffer
$out.println("some content")##
$out.println("some content")##
$out.println("some content")##
$out.println("some content")##
$out.println("some content")##
$out.println("some content")##
$out.println("some content")##
$out.println("some content")##
$out.println("some content")##
$out.println("some content")
## Make sure everything is sent
$out.flush()##
## Indicate XWiki that you already sent the answer
$xcontext.setFinished(true)##
and had only blank pages/
That's because you did not really wrote anything ;)
I made a mistake in my example, it's
#set($out = $response.outputStream)
without the parentheses.
Paul
_______________________________________________
users mailing list
users(a)xwiki.org
http://lists.xwiki.org/mailman/listinfo/users
--
Thomas Mortagne
_______________________________________________
users mailing list
users(a)xwiki.org
http://lists.xwiki.org/mailman/listinfo/users
4287
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11 comments
3 participants
participants (3)
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Thomas Mortagne