CODEWITHSUNDEEP
ruby-on-railsruby
gotnull
gotnull

Reputation: 27224

Ruby/Rails - Converting Google Apps Script to Rails

I'm having a bit of trouble converting the following method in a Google App Script to work with Rails:

Tutorial: Parsing an XML Document

This is the method I'd like to convert:

function parse(txt) {
  var doc = Xml.parse(txt, true);
  var attr = doc.spellcheck;
  if (attr) {
    return "Cannot find actor: " + attr.name;
  }

  var actors = doc.html.head.getElements("actor");      
  var movies = doc.html.head.getElements("movie");

  if (!actors || actors.length ==0) {
    return "no match found";
  }

  var movieIndex = 0;
  var r = '';
  var firstPerson = true;
  for (var i in actors) {
    r = r + actors[i].getText();
    if (movies[movieIndex]) {
      r = r + (firstPerson ? "" : " who") + " was in " +
        movies[movieIndex].getText() + " with ";
    }
    movieIndex++;
    firstPerson = false;
  }

  return r;
}

This is what I have so far:

I'm using Nokogiri to parse the XML:

uri = "http://oracleofbacon.org/cgi-bin/xml?a=Kevin%20Bacon&b=#{to.strip.to_hash}&u=1&p=google-apps"
doc = Nokogiri::XML(open(uri))

My attempt at conversion:

def parse(doc)

    attr = doc.xpath("//link//actor").first # => "<actor>Miley Cyrus</actor>"

    if (!attr)
        return "Cannot find actor: #{attr}"
    end

    actors = doc.xpath("//link//actor")
    movies = doc.xpath("//link//movie")

    if (!actors || actors.length == 0)
        return "No match found."
    end

    movieIndex = 0
    r = ""
    firstPerson = true

    actors.each do |actor|
        r = r + actor

        if (movies[movieIndex])
            r = r + (firstPerson ? "" : " who") + " was in #{movies[movieIndex]} with "
        end

        movieIndex++
        firstPerson = false;
    end

    return r
end

I get an error:

`block in parse': undefined method `+@' for false:FalseClass (NoMethodError)

This is happening on the firstPerson = false line.

Upvotes: 1

Views: 385

Answers (1)

Jakob S
Jakob S

Reputation: 20125

actors.each yields each actor node to the block. So your i variable contains an actor element (Nokogiri::XML::Element). Thus actors[i] doesn't make sense, which is why you get the first error.

You're probably looking for

actors.each do |actor|
  r = r + actor
  [...]
end

although I am not sure what will happen when you attempt to concatenate a Nokogiri::XML::Element to a String.

Also, movieIndex++ doesn't do what you hope. You want movieIndex += 1.

Although, since you're just incrementing movieIndex on every loop, you could remove the line entirely and do actors.each do |actor, movieIndex| instead.

Upvotes: 4

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