How do you scrape AJAX pages?

Overview:

All screen scraping first requires manual review of the page you want to extract resources from. When dealing with AJAX you usually just need to analyze a bit more than just simply the HTML.

When dealing with AJAX this just means that the value you want is not in the initial HTML document that you requested, but that javascript will be exectued which asks the server for the extra information you want.

You can therefore usually simply analyze the javascript and see which request the javascript makes and just call this URL instead from the start.

Example:

Take this as an example, assume the page you want to scrape from has the following script:

<script type="text/javascript">
function ajaxFunction()
{
var xmlHttp;
try
  {
  // Firefox, Opera 8.0+, Safari
  xmlHttp=new XMLHttpRequest();
  }
catch (e)
  {
  // Internet Explorer
  try
    {
    xmlHttp=new ActiveXObject("Msxml2.XMLHTTP");
    }
  catch (e)
    {
    try
      {
      xmlHttp=new ActiveXObject("Microsoft.XMLHTTP");
      }
    catch (e)
      {
      alert("Your browser does not support AJAX!");
      return false;
      }
    }
  }
  xmlHttp.onreadystatechange=function()
    {
    if(xmlHttp.readyState==4)
      {
      document.myForm.time.value=xmlHttp.responseText;
      }
    }
  xmlHttp.open("GET","time.asp",true);
  xmlHttp.send(null);
  }
</script>

Then all you need to do is instead do an HTTP request to time.asp of the same server instead. Example from w3schools.


Sporce: http://stackoverflow.com/questions/260540/how-do-you-scrape-ajax-pages

using Perl to scrape a website

I am interested in writing a perl script that goes to the following link and extracts the number 1975: https://familysearch.org/search/collection/results#count=20&query=%2Bevent_place_level_1%3ACalifornia%20%2Bevent_place_level_2%3A%22San%20Diego%22%20%2Bbirth_year%3A1923-1923~%20%2Bgender%3AM%20%2Brace%3AWhite&collection_id=2000219

That website is the amount of white men born in the year 1923 who live in San Diego County, California in 1940. I am trying to do this in a loop structure to generalize over multiple counties and birth years.

In the file, locations.txt, I put the list of counties, such as San Diego County.

The current code runs, but instead of the # 1975, it displays unknown. The number 1975 should be in $val\n.

I would very much appreciate any help!

#!/usr/bin/perl

use strict;

use LWP::Simple;

open(L, "locations26.txt");

my $url = 'https://familysearch.org/search/collection/results#count=20&query=%2Bevent_place_level_1%3A%22California%22%20%2Bevent_place_level_2%3A%22%LOCATION%%22%20%2Bbirth_year%3A%YEAR%-%YEAR%~%20%2Bgender%3AM%20%2Brace%3AWhite&collection_id=2000219';

open(O, ">out26.txt");
 my $oldh = select(O);
 $| = 1;
 select($oldh);
 while (my $location = <L>) {
     chomp($location);
     $location =~ s/ /+/g;
      foreach my $year (1923..1923) {
                 my $u = $url;
                 $u =~ s/%LOCATION%/$location/;
                 $u =~ s/%YEAR%/$year/;
                 #print "$u\n";
                 my $content = get($u);
                 my $val = 'unknown';
                 if ($content =~ / of .strong.([0-9,]+)..strong. /) {
                         $val = $1;
                 }
                 $val =~ s/,//g;
                 $location =~ s/\+/ /g;
                 print "'$location',$year,$val\n";
                 print O "'$location',$year,$val\n";
         }
     }

Update: API is not a viable solution. I have been in contact with the site developer. The API does not apply to that part of the webpage. Hence, any solution pertaining to JSON will not be applicbale.



Source: http://stackoverflow.com/questions/14654288/using-perl-to-scrape-a-website

PDF scraping using R

I have been using the XML package successfully for extracting HTML tables but want to extend to PDF's. From previous questions it does not appear that there is a simple R solution but wondered if there had been any recent developments

Failing that, is there some way in Python (in which I am a complete Novice) to obtain and manipulate pdfs so that I could finish the job off with the R XML package

Extracting text from PDFs is hard, and nearly always requires lots of care.

I'd start with the command line tools such as pdftotext and see what they spit out. The problem is that PDFs can store the text in any order, can use awkward font encodings, and can do things like use ligature characters (the joined up 'ff' and 'ij' that you see in proper typesetting) to throw you.

pdftotext is installable on any Linux system



Source: http://stackoverflow.com/questions/7918718/pdf-scraping-using-r

Php Scraping data from a website

I am very new to programming and need a little help with getting data from a website and passing it into my PHP script.

The website is http://www.birthdatabase.com/.

I would like to plug in a name (First and Last) and retrieve the result. I know you can query the site by passing the name in the URL, but I am having problems scraping the results.

http://www.birthdatabase.com/cgi-bin/query.pl?textfield=FIRST&textfield2=LAST&age=&affid=

I am using the file_get_contents($URL) function to get the page but need help after that. Specifically, I would like to scrape only the results from a certain state if there are multiple results for that name.



You need the awesome simple_html_dom class.

With this class you can query the webpage's DOM in a similar way to jQuery.

First include the class in your page, then get the page content with this snippet:

$html = file_get_html('http://www.birthdatabase.com/cgi-bin/query.pl?textfield=' . $first . '&textfield2=' . $last . '&age=&affid=');

Then you can use CSS selections to scrape your data (something like this):

$n = 0;
foreach($html->find('table tbody tr td div font b table tbody') as $element) {
    @$row[$n]['tr']  = $element->find('tr')->text;
    $n++;
}

// output your data
print_r($row);



Source: http://stackoverflow.com/questions/15601584/php-scraping-data-from-a-website

Obtaining reddit data

I am interested in obtaining data from different reddit subreddits. Does anyone know

if there is a reddit/other api similar like twitter does to crawl all the pages?


Yes, reddit has an API that can be used for a variety of purposes such as data

collection, automatic commenting bots, or even to assist in subreddit moderation.

There are a few places to discover information on reddit's API:

    github reddit wiki -- provides the overview and rules for using reddit's API

(follow the rules)
    automatically generated API docs -- provides information on the requests needed to

access most of the API endpoints
    /r/redditdev -- the reddit community dedicated to answering questions both about

reddit's source code and about reddit's API

If there is a particular programming language you are already familiar with, you

should check out the existing set of API wrappers for various languages. Despite my

bias (I am the package maintainer) I am quite certain PRAW, for python, has support

for the largest number of reddit API features.



Source: http://stackoverflow.com/questions/14322834/obtaining-reddit-data

Scraping dynamic data

I am scraping profiles on ask.fm for a research question. The problem is that only the top most recent questions are viewable and I have to click "view more" to see the next 15.

The source code for clicking view more looks like this:

<input class="submit-button-more submit-button-more-active" name="commit" onclick="return Forms.More.allowSubmit(this)" type="submit" value="View more" />

What is an easy way of calling this 4 times before scraping it. I want the most recent 60 posts on the site. Python is preferable.

You could probably use selenium to browse to the website and click on the button/link a few times. You can get that here:

    https://pypi.python.org/pypi/selenium

Or you might be able to do it with mechanize:

    http://wwwsearch.sourceforge.net/mechanize/

I have also heard good things about twill, but never used it myself:

    http://twill.idyll.org/



Source: http://stackoverflow.com/questions/19437782/scraping-dynamic-data

PDF Scraping: Making Modern File Formats More Accessible

Data scraping is the process of automatically sorting through information contained on the internet inside html, PDF or other documents and collecting relevant information to into databases and spreadsheets for later retrieval. On most websites, the text is easily and accessibly written in the source code but an increasing number of businesses are using Adobe PDF format (Portable Document Format: A format which can be viewed by the free Adobe Acrobat software on almost any operating system. See below for a link.). The advantage of PDF format is that the document looks exactly the same no matter which computer you view it from making it ideal for business forms, specification sheets, etc.; the disadvantage is that the text is converted into an image from which you often cannot easily copy and paste. PDF Scraping is the process of data scraping information contained in PDF files. To PDF scrape a PDF document, you must employ a more diverse set of tools.

There are two main types of PDF files: those built from a text file and those built from an image (likely scanned in). Adobe's own software is capable of PDF scraping from text-based PDF files but special tools are needed for PDF scraping text from image-based PDF files. The primary tool for PDF scraping is the OCR program. OCR, or Optical Character Recognition, programs scan a document for small pictures that they can separate into letters. These pictures are then compared to actual letters and if matches are found, the letters are copied into a file. OCR programs can perform PDF scraping of image-based PDF files quite accurately but they are not perfect.

Once the OCR program or Adobe program has finished PDF scraping a document, you can search through the data to find the parts you are most interested in. This information can then be stored into your favorite database or spreadsheet program. Some PDF scraping programs can sort the data into databases and/or spreadsheets automatically making your job that much easier.

Quite often you will not find a PDF scraping program that will obtain exactly the data you want without customization. Surprisingly a search on Google only turned up one business, (the amusingly named ScrapeGoat.com http://www.ScrapeGoat.com) that will create a customized PDF scraping utility for your project. A handful of off the shelf utilities claim to be customizable, but seem to require a bit of programming knowledge and time commitment to use effectively. Obtaining the data yourself with one of these tools may be possible but will likely prove quite tedious and time consuming. It may be advisable to contract a company that specializes in PDF scraping to do it for you quickly and professionally.

Let's explore some real world examples of the uses of PDF scraping technology. A group at Cornell University wanted to improve a database of technical documents in PDF format by taking the old PDF file where the links and references were just images of text and changing the links and references into working clickable links thus making the database easy to navigate and cross-reference. They employed a PDF scraping utility to deconstruct the PDF files and figure out where the links were. They then could create a simple script to re-create the PDF files with working links replacing the old text image.

A computer hardware vendor wanted to display specifications data for his hardware on his website. He hired a company to perform PDF scraping of the hardware documentation on the manufacturers' website and save the PDF scraped data into a database he could use to update his webpage automatically.

PDF Scraping is just collecting information that is available on the public internet. PDF Scraping does not violate copyright laws.

PDF Scraping is a great new technology that can significantly reduce your workload if it involves retrieving information from PDF files. Applications exist that can help you with smaller, easier PDF Scraping projects but companies exist that will create custom applications for larger or more intricate PDF Scraping jobs.

Source:http://ezinearticles.com/?PDF-Scraping:-Making-Modern-File-Formats-More-Accessible&id=193321

Scraping data from National weather services

Hi I want to get the latest weather data from the link below, meaning the very first row of data, I am trying to scrape the data but have not been successful in doing so. Can anyone please help, or if you know any better way point me to that direction thanks!

this is what i have,

$data = file_get_contents('http://w1.weather.gov/obhistory/KIKV.html');

$regex = '/<td>(.+?) </td>/';

preg_match($regex,$data,$match);

var_dump($match);

echo $match[1];

i get an error on '/(.+?) /' this line that "Unknown modifier 't'" ? Any suggestion

1 Answer

Although parsing html with a regex is usually a very bad idea, the error you are receiving, is caused by the / character. You are using that character as the delimiter for your pattern, so you need to escape it or use another character:

$regex = '/<td>(.+?) <\/td>/';

or

$regex = '#<td>(.+?) </td>#';

Source:http://stackoverflow.com/questions/11943420/scraping-data-from-national-weather-services

Scrape Online Selling - Estate Sales

You can find a number of real bargains and few great items to vend at estate sales. The true estate sales are exactly as the name denotes; when someone tries to sell an entire estate or house full of items. The items are generally sold individually or in lots. An estate sale transpires when somebody may have passed away and no one knows what to do with all their junk. Perhaps the relatives can't take all the stuff with them. They hired the company to perform an estate sale or are performing the estate sale themselves.

At a typical sale you will see the house and everything attached to it will be for sale. These sales are publicized in your local newspaper's classified ads section. Estate sales are more modest than garage sales as there are lots of deals to be made.

Estate Sales Tips

• Get there early! Just as with garage sales, the most valuable items are going to be gone in the first few hours.

• Haggle. It is still a good idea to try to lower the sales price of items you are thinking of buying.

• Return to the sale the next day. Most os the time, these types of sales are two day events. I have found that on the second day the operators usually lower their prices significantly. The incentive is also there for the operators to unload everything that is left over.

• Introduce yourself. Usually these type of sales are performed by companies on behalf of the family of the estate. You can leave your business card with the operators and ask them to give you a call about future estate sales. In fact, most of the companies that perform the these sales let you sign up to be notified by e-mail of up and coming sales.

Used Bookstores

If you have any used bookstores around your area you can use the store to find used books to sell books online. Most used bookstores get infested with books but have a limited space in which to store all those books. Because of this, they may be willing to sell you some of their overstocked inventory at a deep discount.

It never hurts to speak to the owner or manager and try to get them to sell you some of their inventory. You can leave them with your business card and let them know that you are always in the market for volume sales. Most owners will always listen to a buyer who is willing to buy in volume since shelf space is a large problem for traditional brick and mortar used bookstores.

Source: http://ezinearticles.com/?Scrape-Online-Selling---Estate-Sales&id=7413912