Rails - Feb 2011 - Using Nokogiri to insert a <span> tag into existing text

All,

I''m using Nokogiri to handle the following problem:

I have a piece of HTML, and for certain text nodes, I need to insert
<span> tags into the text of these nodes at a certain place.

What I am doing is finding the place where I want to insert the <span>,
let''s say index X of the text node''s text, and doing the
following:

1) Setting the node''s text to just what is before index X
2) Adding the <span> as a next sibling to the original node
3) Adding another next sibling to the original node that is another text
node, whose contents are the rest of the text in the original node.

I can pass a string with "<span>blah</span>" to
Node#add_next_sibling
handle #2.

I''m having trouble with creating a new text node and passing it to
Node#add_next_sibling though.

1) Does anyone have an example of creating a new text node in
Nokogiri?

2) Is there a simpler way to do this than splitting up one text node
into 3 nodes?

Many thanks,
Wes

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On Feb 19, 2011, at 7:39 PM, Wes Gamble wrote:
> All,
>
> I''m using Nokogiri to handle the following problem:
>
> I have a piece of HTML, and for certain text nodes, I need to insert
> <span> tags into the text of these nodes at a certain place.
>
> What I am doing is finding the place where I want to insert the  
> <span>,
> let''s say index X of the text node''s text, and doing the
following:
>
> 1) Setting the node''s text to just what is before index X
> 2) Adding the <span> as a next sibling to the original node
> 3) Adding another next sibling to the original node that is another  
> text
> node, whose contents are the rest of the text in the original node.
>
> I can pass a string with "<span>blah</span>" to
Node#add_next_sibling
> handle #2.
>
> I''m having trouble with creating a new text node and passing it to
> Node#add_next_sibling though.
>
> 1) Does anyone have an example of creating a new text node in
> Nokogiri?
>
> 2) Is there a simpler way to do this than splitting up one text node
> into 3 nodes?
Yes. If you have a handle to that text node already, simply use the  
content= method to write your new html into it as text. Build that  
text up using a regular expression or concatenation in normal Ruby  
text processing mode. As long as you don''t need to further modify that
node as if it was a nodeset, this will be the simplest method I can  
think of.

If you later need to access that span as a new Nokogiri node, you will  
have to do something more complex.

Walter
>
> Many thanks,
> Wes
>
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Thanks Walter, ended up with this:

doc = Nokogiri::HTML.parse(File.new(merge_path))
nodes = doc.xpath("//text()[contains(.,''MERGE'')]")
nodes.each do |node|
  text = node.text
  if md = text.match(/.{2}MERGE(\d+).{2}/)
    start_index = text.index(md[0])
    start_span_tag = "<span
id=''merge_#{md[1]}''>"
    end_index = start_index + start_span_tag.length + md[0].length
    node.content = text.insert(start_index, 
start_span_tag).insert(end_index, ''</span>'')
  end
end

Works great.

Wes

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This doesn''t work - when I write this back out to a file the
<span> is
escaped.

Perhaps I should have mentioned that I needed to re-serialize the 
resulting HTML.

Wes

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Node.content= takes text, not more nodes. Try using Node.inner_html =  
instead.

Walter

On Feb 24, 2011, at 11:12 PM, Wes Gamble wrote:
> This doesn''t work - when I write this back out to a file the
<span> is
> escaped.
>
> Perhaps I should have mentioned that I needed to re-serialize the
> resulting HTML.
>
> Wes
>
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>
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This works:

#Surround all of the text (NOT attribute value) merge fields with <span> 
tags for ease of manipulation later

doc = Nokogiri::HTML.parse(html)
nodes = doc.xpath("//text()[contains(.,''MERGE'')]")
nodes.each do |node|
  text = node.text.dup
  if md = text.match(/.{2}MERGE(\d+).{2}/)
    start_index = text.index(md[0])
    end_index = start_index + md[0].length
    node = node.replace(text[0..start_index - 1])[0]
    node.after("<span 
id=''merge_#{md[1]}''>#{md[0]}</span>#{text[end_index..-1]}")
   end
end

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I tried Node.inner_html= to no avail, setting it to the string that 
resulted if I interpolated the <span> where I wanted it.  Not sure why 
it didn''t work, but the replace/after works, so I went with that.

Thanks for the help.

Wes

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That''s because Node.inner_html takes nodes, not strings as input. Glad
you got it working.

Walter

On Feb 28, 2011, at 10:03 PM, Wes Gamble wrote:
> I tried Node.inner_html= to no avail, setting it to the string that
> resulted if I interpolated the <span> where I wanted it.  Not sure
why
> it didn''t work, but the replace/after works, so I went with that.
>
> Thanks for the help.
>
> Wes
>
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