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im using x-ray, which is great but lack of tutorial. anyway, I use an array of urls named urls. In the loop ,each url fetched and return result through callback. in the callback function i need to know what was the url which was parsed. How can i know which url is returning if the callback returns only err and results? (is it really an x-ray question or js)

 xrayRamiLevy = function(){
  var index = 0;
  for (index; index < urls.length; index++){
   x(urls[index].url, '.product_item',
  [{
      title : '.prodDescDiv h3',
      description : '.prodBrand',
      imageUrl : '.image_icons_zone .image img@src',
      onclick : '.image_icons_zone .image a @onclick',
  }]
)
(function(err, results){
    for (var i = 0; i < results.length; i++){

      var s = results[i].onclick.substr(0, results[i].onclick.lastIndexOf("'"));
      s = s.slice(s.lastIndexOf("'") + 1);
      results[i].catalogueNumber = s;
      delete results[i].onclick;
      if (results[i].description !== undefined && results[i].description.length > 0)
      s = results[i].description.replace(/\s+/g, ' ').trim();
      results[i].description = s;

      if (urls[index].category !== undefined && urls[index].category.length > 0)
      results[i].categoriesIds = urls[index].category;

      if (urls[index].subcategory !== undefined && urls[index].subcategory.length > 0)
      results[i].subcategoriesIds = urls[index].subcategory;

    }
    fs.writeFile("./results.json", JSON.stringify(results, null, '\t'));
});

} }

dang
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2 Answers2

1

I didn't fully get your example, HOWEVER:

urls.forEach(function(url, index){
  //whatever you need to do to prep your call to x
 var callback = x(url, '.product_item', ...);
 callback(wrappedCallback(url));
}

function wrappedCallback(url) {
  return function(err, results){
    // url is defined here
  }
};
orotemo
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1

See example of getting the url using JS closure. Note how the URL from the array is available in the fn callback.

var Xray = require('x-ray');
var util = require('util');
var x = Xray();

var sitesToHandle = ['https://dribbble.com?x=1', 'https://dribbble.com?x=2'];
sitesToHandle.forEach((urlToHandle) => {
  x(urlToHandle, 'li.group', [{
    title: '.dribbble-img strong',
    image: '.dribbble-img [data-src]@data-src',
  }]).(function (err, results) {
    console.log(`let's now handle the result of ${urlToHandle}, the results are ${util.inspect(results)}`);
  });
});

p.s. side note, when handling the returned errors, you might take a look at an error handling guide that I just wrote here

Yonatan
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  • thank you @Yonatan should i really use the $ sign? where the util.inspect came from? – dang May 17 '16 at 09:46
  • No, it's only meant to include a variable within a string. Also the util.inspect is used to print objects to the log, it's not neccessary – Yonatan May 17 '16 at 09:48