Ruby regex doesn't recognize beginning of string - ruby

I want to replace the "text" contains http link with the actual HTML markup for this link.
Here is my Ruby code
url_check = Regexp.new( '(\A|[\n ])([\w]+?://[\w]+[^ \"\r\n\t<]*)', Regexp::MULTILINE | Regexp::IGNORECASE )
self.gsub!(url_check, '\1\2')
to_s
Here is a test case:
This is entrance page for the service (using HTML):
http://foobar.org/resources?format=html
Let us pick the "contributions" namespace: http://foobar.org/
The link is created only for the second case, but not for the first (which has several line breaks before)

I suggest using \b (word boundary) instead of new-line/start-of-the-line detection:
.gsub!(/\b([\w]+?:\/\/[\w]+[^ \"\r\n\t<]*)/i, '\1')
you don't need "http:" in replacement as you already match for protocol.

Related

How to add a namespace to existing xml file

I want to open this file and get all elements that start with us-gaap.
ftp://ftp.sec.gov/edgar/data/916789/0001558370-15-001143.txt
To get elements I tried like this:
str = '<html><body><us-gaap:foo>foo</us-gaap:foo></body></html>'
doc = Nokogiri::XML(File.read(str))
doc.xpath('//us-gaap:*')
Nokogiri::XML::XPath::SyntaxError: Undefined namespace prefix: //us-gaap:*
from /Users/ironsand/.rbenv/versions/2.2.2/lib/ruby/gems/2.2.0/gems/nokogiri-1.6.7.2/lib/nokogiri/xml/searchable.rb:165:in `evaluate'
doc.namespaces returns {}, so I think I have to add namespace us-gaap.
There are some questions about "adding namespace with Nokogiri", but it looks like about how to create a new XML document, not how to add a namespace to existing documents.
How can I add a namespace to existing document?
I know I can remove the namespace by Nokogiri::XML::Document#remove_namespaces!, but I don't want to use it because it removes also necesarry information.
You have asked an XY Problem. You think that the problem is that you need to add a missing namespace; the real problem is that the file you're trying to parse is not valid XML.
require 'nokogiri'
doc = Nokogiri.XML( IO.read('0001558370-15-001143.txt') )
doc.errors.length
#=> 5716
For example, the <ACCEPTANCE-DATETIME> 'element' opened on line 3 is never closed, and on line 16 there is a raw ampersand in the text:
STANDARD INDUSTRIAL CLASSIFICATION: ELECTRIC HOUSEWARES & FANS [3634]
which ought to be escaped as an entity.
However, the document has valid XML fragments within it! In particular, there is one XML document that defines xmlns:us-gaap namespace, from lines 27243-49312. Let's extract just that, using only the knowledge that the root element defines the namespace we want, and the assumptions that no element with the same name is nested within the document, and that the root element does not have an unescaped > character in any attribute. (These assumptions are valid for this file, but may not be valid for every XML file.)
txt = IO.read('0001558370-15-001143.txt')
gaap_finder = %r{(<(\w+) [^>]+xmlns:us-gaap=.+?</\2>)}m
txt.scan(gaap_finder) do |xml,_|
doc = Nokogiri.XML( xml )
gaaps = doc.xpath('//us-gaap:*')
p gaaps.length
#=> 569
end
The code above handles the case where there may be more than one XML document in the txt file, though in this case there is only one.
Decoded, the gaap_finder regex says this:
%r{...}m — this is a regular expression (that allows slashes in it, unescaped) with "multiline mode", where a period will match newline characters
(...) — capture everything we find
< — start with a literal "less-than" symbol
(\w+) — find one or more word characters (the tag name), and save them
— the word characters must be followed by a space (important to avoid capturing the <xsd:xbrl ...> element in this file)
[^>]+ — followed by one or more characters that is NOT a "greater-than" symbol (to ensure that we stay in the same element that we started in)
xmlns:us-gaap\s*= — followed by this literal namespace declaration (which may have whitespace separating it from the equals sign)
.+? — followed by anything (as little as possible)...
</\2> — ...up until you see a closing tag with the same name as what we captured for the name of the starting tag
Because of the way scan works when the regex has capturing groups, each result is a two-element array, where the first element is the entire captured XML and the second element is the name of the tag that we captured (which we "discard" by assigning it to the _ variable).
If you want to be less magic about your capturing, the text file format appears to always wrap each XML document in <XBRL>...</XBRL>. So, you could do this to process every XML file (there are seven, five of which do not happen to have any us-gaap namespaces):
txt = IO.read('0001558370-15-001143.txt')
xbrls = %r{(?<=<XBRL>).+?(?=</XBRL>)}m # find text inside <XBRL>…</XBRL>
txt.scan(xbrls) do |xml|
doc = Nokogiri.XML( xml )
if doc.namespaces["xmlns:us-gaap"]
gaaps = doc.xpath('//us-gaap:*')
p gaaps.length
end
end
#=> 569
#=> 0 (for the XML Schema document that defines the namespace)
I couldn't figure out how to update an existing doc with a new namespace, but since Nokogiri will recognize namespaces on the root element, and those namespaces are, syntactically, just attributes, you can update the document with a new namespace declaration, serialize the doc to a string, and re-parse it:
str = '<html><body><us-gaap:foo>foo</us-gaap:foo></body></html>'
doc_without_ns = Nokogiri::XML(str)
doc_without_ns.root['xmlns:us-gaap'] = 'http://your/actual/ns/here'
doc = Nokogiri::XML(doc_without_ns.to_xml)
doc.xpath("//us-gaap:*")
# Returns [#<Nokogiri::XML::Element:0x3ff375583f9c name="foo" namespace=#<Nokogiri::XML::Namespace:0x3ff375583f24 prefix="us-gaap" href="http://your/actual/ns/here"> children=[#<Nokogiri::XML::Text:0x3ff375583768 "foo">]>]

Regular Expression find usage of word after "/" in URL

I am trying to parse through URLs using Ruby and return the URLs that match a word after the "/" in .com , .org , etc.
If I am trying to capture "questions" in a URL such as
https://stackoverflow.com/questions I also want to be able to capture https://stackoverflow.com/blah/questions. But I do not want to capture https://stackoverflow.com/queStioNs.
Currently my expression can match https://stackoverflow.com/questions but cannot match with "questions" after another "/", or 2 "/"s, etc.
The end of my regular expression is using \bquestions\.
I tried doing ([a-zA-Z]+\W{1}+\bjob\b|\bjob\b) but this only gets me URLs with /questions and /blah/questions but not /blah/bleh/questions.
What am I doing wrong and how do I match what I need?
You don't actually need a regex for this, you can instead use the URI module:
require 'uri'
urls = ['https://stackoverflow.com/blah/questions', 'https://stackoverflow.com/queStioNs']
urls.each do |url|
the_path = URI(url).path
puts the_path if the_path.include?'questions'
end
I don't know whether there is any simple way around, here is my solution:
regexp = '^(https|http)?:\/\/[\w]+\.(com|org|edu)(\/{1}[a-z]+)*$'
group_length = "https://stackoverflow.com/blah/questions".match(regexp).length
"https://stackoverflow.com/blah/questions".match(regexp)[group_length - 1].gsub("/","")
It will return 'questions'.
Update as per you comments below:
use [\S]*(\/questions){1}$
Hope it helps :)

Replacing scan by gsub in Ruby: how to allow code in gsub block?

I am parsing a Wiki text from an XML dump, for a string named 'section' which includes templates in double braces, including some arguments, which I want to reorganize.
This has an example named TextTerm:
section="Sample of a text with a first template {{TextTerm|arg1a|arg2a|arg3a...}} and then a second {{TextTerm|arg1b|arg2b|arg3b...}} etc."
I can use scan and a regex to get each template and work on it on a loop using:
section.scan(/\{\{(TextTerm)\|(.*?)\|(.*?)\}\}/i).each { |item| puts "1=" + item[1] # arg1a etc.}
And, I have been able to extract the database of the first argument of the template.
Now I also want to replace the name of the template "NewTextTerm" and reorganize its arguments by placing the second argument in place of the first.
Can I do it in the same loop? For example by changing scan by a gsub(rgexp){ block}:
section.gsub!(/\{\{(TextTerm)\|(.*?)\|(.*?)\}\}/) { |item| '{{NewTextTerm|\2|\1}}'}
I get:
"Sample of a text with a first template {{NewTextTerm|\\2|\\1}} and then a second {{NewTextTerm|\\2|\\1}} etc."
meaning that the arguments of the regexp are not recognized. Even if it worked, I would like to have some place within the gsub block to work on the arguments. For example, I can't have a puts in the gsub block similar to the scan().each block but only a string to be substituted.
Any ideas are welcome.
PS: Some editing: braces and "section= added", code is complete.
When you have the replacement as a string argument, you can use '\1', etc. like this:
string.gsub!(regex, '...\1...\2...')
When you have the replacement as a block, you can use "#$1", etc. like this:
string.gsub!(regex){"...#$1...#$2..."}
You are mixing the uses. Stick to either one.
Yes, changing the quote by a double quote isn't enough, #$1 is the answer. Here is the complete code:
section="Sample of a text with a first template {{TextTerm|arg1a|arg2a|arg3a...}} and then a second {{TextTerm|arg1b|arg2b|arg3b...}} etc."
section.gsub(/\{\{(TextTerm)\|(.*?)\|(.*?)\}\}/) { |item| "{{New#$1|#$3|#$2}}"}
"Sample of a text with a first template {{NewTextTerm|arg2a|arg3a...|arg1a}} and then a second {{NewTextTerm|arg2b|arg3b...|arg1b}} etc."
Thus, it works. Thanks.
But now I have to replace the string, by a "function" returning the changed string:
def stringreturn(arg1,arg2,arg3) strr = "{{New"+arg1 + arg3 +arg2 + "}}"; return strr ; end
and
section.gsub(/\{\{(TextTerm)\|(.*?)\|(.*?)\}\}/) { |item| stringreturn("#$1","|#$2","|#$3") }
will return:
"Sample of a text with a first template {{NewTextTerm|arg2a|arg3a...|arg1a}} and then a second {{NewTextTerm|arg2b|arg3b...|arg1b}} etc."
Thanks to all!
There is probably a better way to manipulate arguments in MediaWiki templates using Ruby.

Disable HTML within XML escaping with Nokogiri

I'm trying to parse an XML document from the Google Directions API.
This is what I've got so far:
x = Nokogiri::XML(GoogleDirections.new("48170", "48104").xml)
x.xpath("//DirectionsResponse//route//leg//step").each do |q|
q.xpath("html_instructions").each do |h|
puts h.inner_html
end
end
The output looks like this:
Head <b>south</b> on <b>Hidden Pond Dr</b> toward <b>Ironwood Ct</b>
Turn <b>right</b> onto <b>N Territorial Rd</b>
Turn <b>left</b> onto <b>Gotfredson Rd</b>
...
I would like the output to be:
Turn <b>right</b> onto <b>N Territorial Rd</b>
The problem seems to be Nokogiri escaping the html within the xml
I trust Google, but I think it would be also good to sanitize it further to:
Turn right onto N Territorial Rd
But I can't (using sanitize perhaps) without the raw xml. Ideas?
Because I don't have the Google Directions API installed I can't access the XML, but I have a strong suspicion the problem is the result of telling Nokogiri you're dealing with XML. As a result it's going to return you the HTML encoded like it should be in XML.
You can unescape the HTML using something like:
CGI::unescape_html('Head <b>south</b> on <b>Hidden Pond Dr</b> toward <b>Ironwood Ct</b>')
=> "Head <b>south</b> on <b>Hidden Pond Dr</b> toward <b>Ironwood Ct</b>\n"
unescape_html is an alias to unescapeHTML:
Unescape a string that has been HTML-escaped
CGI::unescapeHTML("Usage: foo "bar" <baz>")
# => "Usage: foo \"bar\" "
I had to think about this a bit more. It's something I've run into, but it was one of those things that escaped me during the rush at work. The fix is simple: You're using the wrong method to retrieve the content. Instead of:
puts h.inner_html
Use:
puts h.text
I proved this using:
require 'httpclient'
require 'nokogiri'
# This URL comes from: https://developers.google.com/maps/documentation/directions/#XML
url = 'http://maps.googleapis.com/maps/api/directions/xml?origin=Chicago,IL&destination=Los+Angeles,CA&waypoints=Joplin,MO|Oklahoma+City,OK&sensor=false'
clnt = HTTPClient.new
doc = Nokogiri::XML(clnt.get_content(url))
doc.search('html_instructions').each do |html|
puts html.text
end
Which outputs:
Head <b>south</b> on <b>S Federal St</b> toward <b>W Van Buren St</b>
Turn <b>right</b> onto <b>W Congress Pkwy</b>
Continue onto <b>I-290 W</b>
[...]
The difference is that inner_html is reading the content of the node directly, without decoding. text decodes it for you. text, to_str and inner_text are aliased to content internally in Nokogiri::XML::Node for our parsing pleasure.
Wrap your nodes in CDATA:
def wrap_in_cdata(node)
# Using Nokogiri::XML::Node#content instead of #inner_html (which
# escapes HTML entities) so nested nodes will not work
node.inner_html = node.document.create_cdata(node.content)
node
end
Nokogiri::XML::Node#inner_html escapes HTML entities except in CDATA sections.
fragment = Nokogiri::HTML.fragment "<div>Here is an unescaped string: <span>Turn left > right > straight & reach your destination.</span></div>"
puts fragment.inner_html
# <div>Here is an unescaped string: <span>Turn left > right > straight & reach your destination.</span></div>
fragment.xpath(".//span").each {|node| node.inner_html = node.document.create_cdata(node.content) }
fragment.inner_html
# <div>Here is an unescaped string: <span>Turn left > right > straight & reach your destination.</span>\n</div>
This is not a great or DRY solution, but it works:
puts h.inner_html.gsub("<b>" , "").gsub("</b>", "").gsub("<div style=\"font-size:0.9em\">", "").gsub("</div>", "")

Ruby: replace a given URL in an HTML string

In Ruby, I want to replace a given URL in an HTML string.
Here is my unsuccessful attempt:
escaped_url = url.gsub(/\//,"\/").gsub(/\./,"\.").gsub(/\?/,"\?")
path_regexp = Regexp.new(escaped_url)
html.gsub!(path_regexp, new_url)
Note: url is actually a Google Chart request URL I wrote, which will not have more special characters than /?|.=%:
The gsub method can take a string or a Regexp as its first argument, same goes for gsub!. For example:
>> 'here is some ..text.. xxtextxx'.gsub('..text..', 'pancakes')
=> "here is some pancakes xxtextxx"
So you don't need to bother with a regex or escaping at all, just do a straight string replacement:
html.gsub!(url, new_url)
Or better, use an HTML parser to find the particular node you're looking for and do a simple attribute assignment.
I think you're looking for something like:
path_regexp = Regexp.new(Regexp.escape(url))

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