Re: [xwiki-devs] [xwiki-notifications] r14425 - sandbox/xwiki-plugin-officeimporter/src/main/java/com/xpn/xwiki/plugin/officeimporter/filter
24 Nov
2008
24 Nov
'08
6:16 p.m.
Hi Asiri,
On Nov 24, 2008, at 6:08 PM, asiri (SVN) wrote:
Author: asiri
Date: 2008-11-24 18:08:51 +0100 (Mon, 24 Nov 2008)
New Revision: 14425
Modified:
sandbox/xwiki-plugin-officeimporter/src/main/java/com/xpn/xwiki/
plugin/officeimporter/filter/RedundantTagFilter.java
Log:
XAOFFICE-1 : Develop the initial feature set for office-importer
plugin.
* Added support for filtering empty / redundant paragraphs.
Modified: sandbox/xwiki-plugin-officeimporter/src/main/java/com/xpn/
xwiki/plugin/officeimporter/filter/RedundantTagFilter.java
===================================================================
--- sandbox/xwiki-plugin-officeimporter/src/main/java/com/xpn/xwiki/
plugin/officeimporter/filter/RedundantTagFilter.java 2008-11-24
15:17:17 UTC (rev 14424)
+++ sandbox/xwiki-plugin-officeimporter/src/main/java/com/xpn/xwiki/
plugin/officeimporter/filter/RedundantTagFilter.java 2008-11-24
17:08:51 UTC (rev 14425)
@@ -31,12 +31,13 @@
public void filter(Document document, ImporterContext context)
{
- for(String key : attributeWiseFilteredTags) {
+ for (String key : attributeWiseFilteredTags) {
filterNodesWithZeroAttributes(document.getElementsByTagName(key));
}
- for(String key : contentWiseFilteredTags) {
+ for (String key : contentWiseFilteredTags) {
filterNodesWithEmptyTextContent(document.getElementsByTagName(key));
- }
+ }
+ filterEmptyParagraphs(document);
}
/**
@@ -70,10 +71,35 @@
{
for (int i = 0; i < elements.getLength(); i++) {
Element element = (Element) elements.item(i);
- if (element.getTextContent().trim().equals("")) {
+ if (element.getTextContent().trim().equals("")) {
element.getParentNode().removeChild(element);
i--;
}
}
}
+
+ /**
+ * OpenOffice server generates redundant paragraphs (with empty
content) to achieve spacing.
+ * These paragraphs should be stripped off / replaced with
{@code <br/>} elements appropriately
+ * because otherwise they result in spurious {@code (%%)}
elements in generated xwiki content.
+ *
+ * @param document The html document.
+ */
+ private void filterEmptyParagraphs(Document document)
+ {
+ NodeList paragraphs = document.getElementsByTagName("p");
+ for (int i = 0; i < paragraphs.getLength(); i++) {
+ Element paragraph = (Element) paragraphs.item(i);
+ if (paragraph.getTextContent().trim().equals("")) {
+ // We suspect this is an empty paragraph but it is
possible that it contains other
+ // non-textual tags like images. For the moment
we'll only search for internal image
+ // tags, we might have to refine this criterion
later.
+ NodeList internalImages =
paragraph.getElementsByTagName("img");
+ if (internalImages.getLength() == 0) {
+ paragraph.getParentNode().removeChild(paragraph);
+ i--;
I don't understand this algorithm. There can be a lot of other valid
XHTML elements inside a P element (see the XHTML spec). Why are you
searching for IMG tags at all? What about all the other tags?
Again I'm not sure this code is in the right place. For example what
will happen if the user provides an empty P as input for a wiki page
(using XHTML syntax)? Your code will never run in this case.
To be honest I haven't looked at the office importer code for some
time but we really need to be careful to move all generic code outside
of it and into the HTML cleaner or into the XHTML parser. Could you
please check that there are only office-related code in there?
Thanks
-Vincent
24 Nov
24 Nov
6:46 p.m.
New subject: [xwiki-devs] [xwiki-notifications] r14425 - sandbox/xwiki-plugin-officeimporter/src/main/java/com/xpn/xwiki/plugin/officeimporter/filter
Hi Vincent,
Let me explain,
I'm looking for ways to implement a moderate syntax filtering mechanism.
Currently in the strict filtering mode, we strip off most of the attributes
from elements including those of the <p> tag. When we do this, if a
particular <p> element is empty (if it has no textual content), and since
all of it's attributes were stripped off, the resulting xwiki content has no
(%%) elements.
Example : When <p></p> is converted into xwiki/2.0 the result is empty. But
when <p align="justify"></p> is converted into xwiki/2.0 syntax the
result
is (% align="justify"%)
To implement a moderate filtering mechanism, i need to allow the align
attribute of the <p> tag, because that's required to make the content appear
more pleasing to the user. But when I do this, since openoffice server uses
a lot of <p align="justify"></p> (a.k.a empty paragraph elements)
for
spacing, the resulting wiki content contains a lot of isolated
(%align="justify"%) elements which doesn't look nice.
This is the sole reason why I'm trying to rip off empty paragraph elements
so that i can reduce the number of (%%) in the output.
Now why do i look for <img> tags and not others ?
Well, as you can see in the code, there is a check to see if the <p> element
has any text content in it's sub tree. If there is no such text content, we
can guess that this is one of those empty <p> tags used by openoffice server
for spacing. But there are situations where <p> tags are used to enclose
non-textual content like images. So we need to pay special attention to
those cases.
I hope I made myself clear. It's true that it might be too early to think
about a moderate filtering function, but I couldn't resist. The thing is,
the wiki content produced under strict filtering looks very nice, but not
the output of it, It's simply doen't look like the original doc!
Again I'm not sure this code is in the right place.
Well this might be true. I didn't know if html cleaner can be used to strip
off empty <p> tags or such. Is that possible ?
+ /**
+ * OpenOffice server generates redundant paragraphs (with empty
content) to achieve spacing.
+ * These paragraphs should be stripped off / replaced with
{@code <br/>} elements appropriately
+ * because otherwise they result in spurious {@code (%%)}
elements in generated xwiki content.
+ *
+ * @param document The html document.
+ */
+ private void filterEmptyParagraphs(Document document)
+ {
+ NodeList paragraphs = document.getElementsByTagName("p");
+ for (int i = 0; i < paragraphs.getLength(); i++) {
+ Element paragraph = (Element) paragraphs.item(i);
+ if (paragraph.getTextContent().trim().equals("")) {
+ // We suspect this is an empty paragraph but it is
possible that it contains other
+ // non-textual tags like images. For the moment
we'll only search for internal image
+ // tags, we might have to refine this criterion
later.
+ NodeList internalImages =
paragraph.getElementsByTagName("img");
+ if (internalImages.getLength() == 0) {
+ paragraph.getParentNode().removeChild(paragraph);
+ i--;
I don't understand this algorithm. There can be a lot of other valid
XHTML elements inside a P element (see the XHTML spec). Why are you
searching for IMG tags at all? What about all the other tags? For example what
will happen if the user provides an empty P as input for a wiki page
(using XHTML syntax)? Your code will never run in this case.
I don't understand what you mean by this. Are you refferring to a situation
where the orginal office document contains html content entered by the user
? Please explain. Because the only input against which this code executes is
the html output generated from office documents. Not user entered stuff.
To be honest I haven't looked at the office
importer code for some
time but we really need to be careful to move all generic code outside
of it and into the HTML cleaner or into the XHTML parser.
I agree.
Please let me know what you think about my above comments.
Thanks.
- Asiri
7:19 p.m.
New subject: [xwiki-devs] [xwiki-notifications] r14425 - sandbox/xwiki-plugin-officeimporter/src/main/java/com/xpn/xwiki/plugin/officeimporter/filter
On Nov 24, 2008, at 6:46 PM, Asiri Rathnayake wrote:
Users can enter content into pages using different syntaxes. One of
them is HTML/XHTML. So as a user, I can enter:
<p></p>
We can't prevent users entering this. So we need to handle it and
ensure it produces what it should produce. As you can see in my use
case there's no office importer code executed but we still need to
handle empty paragraphs.
All this to say I don't understand why you're replacing empty
paragraphs by BRs. I really don't think it's the role of the office
importer to do this, unless I haven't understood what you're trying to
do.
Thanks
-Vincent
Hi Vincent,
Let me explain,
I'm looking for ways to implement a moderate syntax filtering
mechanism.
Currently in the strict filtering mode, we strip off most of the
attributes
from elements including those of the <p> tag. When we do this, if a
particular <p> element is empty (if it has no textual content), and
since
all of it's attributes were stripped off, the resulting xwiki
content has no
(%%) elements.
Example : When <p></p> is converted into xwiki/2.0 the result is
empty.
Are you sure? Then there's a bug. It should generate 2 empty lines.
+ /**
+ * OpenOffice server generates redundant paragraphs (with empty
content) to achieve spacing.
+ * These paragraphs should be stripped off / replaced with
{@code <br/>} elements appropriately
+ * because otherwise they result in spurious {@code (%%)}
elements in generated xwiki content.
+ *
+ * @param document The html document.
+ */
+ private void filterEmptyParagraphs(Document document)
+ {
+ NodeList paragraphs = document.getElementsByTagName("p");
+ for (int i = 0; i < paragraphs.getLength(); i++) {
+ Element paragraph = (Element) paragraphs.item(i);
+ if (paragraph.getTextContent().trim().equals("")) {
+ // We suspect this is an empty paragraph but it is
possible that it contains other
+ // non-textual tags like images. For the moment
we'll only search for internal image
+ // tags, we might have to refine this criterion
later.
+ NodeList internalImages =
paragraph.getElementsByTagName("img");
+ if (internalImages.getLength() == 0) {
+
paragraph.getParentNode().removeChild(paragraph);
+ i--;
I don't understand this algorithm. There can be a lot of other valid
XHTML elements inside a P element (see the XHTML spec). Why are you
searching for IMG tags at all? What about all the other tags? But
when <p align="justify"></p> is converted into xwiki/2.0 syntax the
result
is (% align="justify"%)
Again there should be 2 new lines below the (%...%) text.
To implement a moderate filtering mechanism, i need to
allow the align
attribute of the <p> tag, because that's required to make the
content appear
more pleasing to the user. But when I do this, since openoffice
server uses
a lot of <p align="justify"></p> (a.k.a empty paragraph elements)
for
spacing, the resulting wiki content contains a lot of isolated
(%align="justify"%) elements which doesn't look nice.
ok so you want to remove attributes for empty paragraphs? Then the
method above is badly named and the javadoc not correct since it says
it removes empty paragraphs.
This is the sole reason why I'm trying to rip off
empty paragraph
elements
so that i can reduce the number of (%%) in the output.
I'm not sure why you'd want to remove empty paragraphs at all. I
understand removing empty paragraph attributes though. An empty
paragraph has a meaning, it means 2 empty lines. If you remove them
won't you loose those empty lines?
Now why do i look for <img> tags and not others
?
Well, as you can see in the code, there is a check to see if the <p>
element
has any text content in it's sub tree. If there is no such text
content, we
can guess that this is one of those empty <p> tags used by
openoffice server
for spacing.
Why? For example:
<p><b>hello</b></p>
The text for P is empty.
But there are situations where <p> tags are used
to enclose
non-textual content like images. So we need to pay special attention
to
those cases.
Why images? Why not the other 20 or so HTML elements that can go in
paragraph? (that was my initial question).
I hope I made myself clear. It's true that it
might be too early to
think
about a moderate filtering function, but I couldn't resist. The
thing is,
the wiki content produced under strict filtering looks very nice,
but not
the output of it, It's simply doen't look like the original doc!
Again I'm not sure this code is in the right place.
Well this might be true. I didn't know if html cleaner can be used
to strip
off empty <p> tags or such. Is that possible ?
You are the one who should tell me! :)
BTW I didn't say HTML cleaner. I said HTML cleaner or XHTML parser.
I'm not working on the office importer so I can't answer but you
should be able to answer.
For example
what
will happen if the user provides an empty P as input for a wiki page
(using XHTML syntax)? Your code will never run in this case.
I don't understand what you mean by this. Are you refferring to a
situation
where the orginal office document contains html content entered by
the user
? Please explain. Because the only input against which this code
executes is
the html output generated from office documents. Not user entered
stuff. To be honest I
haven't looked at the office importer code for some
time but we really need to be careful to move all generic code
outside
of it and into the HTML cleaner or into the XHTML parser.
I agree.
Please let me know what you think about my above comments.
Thanks.
- Asiri
7:41 p.m.
New subject: [xwiki-devs] [xwiki-notifications] r14425 - sandbox/xwiki-plugin-officeimporter/src/main/java/com/xpn/xwiki/plugin/officeimporter/filter
Hi Vincent,
Are you sure? Then there's a bug. It should generate 2 empty lines.
Yes, both of these are true, 2 empty lines are there.
You are correct. I thought of the empty paragraphs as garbage and wanted to
get rid of them. The correct approach indeed is to remove the attributes
from those empty paragraphs (so that we don't loose the empty lines).
Not really, when you do Element.getTextContent() this particular example
will return "hello". Please refer to javadoc
http://java.sun.com/j2se/1.5.0/docs/api/org/w3c/dom/Node.html#setTextConten…
<http://java.sun.com/j2se/1.5.0/docs/api/org/w3c/dom/Node.html#setTextContent%28java.lang.String%29>
I think my previous answer addresses this question also. Even if there are
so many HTML elements, we don't have to worry about all of those as long as
Element.getTextContent() returns "". WDYT ?
Well, the use of empty <p> tags for spacing is specifc to openoffice server.
So yes, I think the code belongs to office-importer.
Users can enter content into pages using different syntaxes. One of
But
when <p align="justify"></p> is converted into xwiki/2.0 syntax
the
result
is (% align="justify"%)
Again there should be 2 new lines below the (%...%) text. To implement a
moderate filtering mechanism, i need to allow the align
attribute of the <p> tag, because that's required to make the
content appear
more pleasing to the user. But when I do this, since openoffice
server uses
a lot of <p align="justify"></p> (a.k.a empty paragraph elements)
for
spacing, the resulting wiki content contains a lot of isolated
(%align="justify"%) elements which doesn't look nice.
ok so you want to remove attributes for empty paragraphs? Then the
method above is badly named and the javadoc not correct since it says
it removes empty paragraphs.
This is the sole reason why I'm trying to rip
off empty paragraph
elements
so that i can reduce the number of (%%) in the output.
I'm not sure why you'd want to remove empty paragraphs at all. I
understand removing empty paragraph attributes though. An empty
paragraph has a meaning, it means 2 empty lines. If you remove them
won't you loose those empty lines? Now why do i
look for <img> tags and not others ?
Well, as you can see in the code, there is a check to see if the <p>
element
has any text content in it's sub tree. If there is no such text
content, we
can guess that this is one of those empty <p> tags used by
openoffice server
for spacing.
Why? For example:
<p><b>hello</b></p>
The text for P is empty. But there are
situations where <p> tags are used to enclose
non-textual content like images. So we need to pay special attention
to
those cases.
Why images? Why not the other 20 or so HTML elements that can go in
paragraph? (that was my initial question). I hope I made myself clear. It's true that it
might be too early to
think
about a moderate filtering function, but I couldn't resist. The
thing is,
the wiki content produced under strict filtering looks very nice,
but not
the output of it, It's simply doen't look like the original doc!
Again I'm not sure this code is in the right place.
Well this might be true. I didn't know if html cleaner can be used
to strip
off empty <p> tags or such. Is that possible ?
You are the one who should tell me! :)
BTW I didn't say HTML cleaner. I said HTML cleaner or XHTML parser.
I'm not working on the office importer so I can't answer but you
should be able to answer. For example
what
will happen if the user provides an empty P as input for a wiki page
(using XHTML syntax)? Your code will never run in this case.
I don't understand what you mean by this. Are you refferring to a
situation
where the orginal office document contains html content entered by
the user
? Please explain. Because the only input against which this code
executes is
the html output generated from office documents. Not user entered
stuff. them is HTML/XHTML. So as a user, I can enter:
<p></p>
We can't prevent users entering this. So we need to handle it and
ensure it produces what it should produce. As you can see in my use
case there's no office importer code executed but we still need to
handle empty paragraphs.
I agree. Stripping empty <p> elements is not a good solution. I will change
the code to make it such that all attributes of empty paragraphs are
removed.
Thanks a lot for pointing this out. :)
- Asiri
5873
days inactive
5873
days old
3 comments
2 participants
participants (2)
-
Asiri Rathnayake -
Vincent Massol