Tuesday, 26 August 2014

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

Sunday, 24 August 2014

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

Saturday, 23 August 2014

Scraping data in dynamic sites

I'm trying to scrape data from our local government. What I want is address from kids adoption offices. Here, in Brazil, all adoptions go through the government. So I have the URL of one office, there are 2 or 3 thousands more. But if I can manage to get one, the others will be easy. I made many attempts, bellow I show three.

The problem could be related to a Javascript (Ajax maybe) that refresh the page.

Note: I am not a PHP developer.

First attempt

echo '<html><head></head><body>';
echo '<h1>Scraper PHP GET 1</h1>';

echo ini_get("allow_url_fopen");
echo ini_get("allow_url_fopen");

// I used this url for test
//$url = 'http://www.portaldaadocao.com.br';

//This is the URL that I really want
$url = 'http://www.cnj.jus.br/cna/Controle/ConsultaPublicaBuscaControle.php?transacao=CONSULTA&vara=2673';

$html = file_get_contents($url);
var_dump($html);

echo '</body></html>';

// Output
// 11
// Warning:
file_get_contents(http://www.cnj.jus.br/cna/Controle/ConsultaPublicaBuscaControle.php?
transacao=CONSULTA&vara=2673) [function.file-get-contents]: failed to open stream: HTTP
request failed! HTTP/1.1 404 Not Found in /home/rsl/www/sc01_get.php on line 14
// bool(false)

Second attempt

echo '<html><head></head><body>';
echo '<h1>Scraper PHP CURL 3</h1>';

// I used this url for test
//$url = 'http://www.portaldaadocao.com.br';

//This is the URL that I really want
$url = 'http://www.cnj.jus.br/cna/Controle/ConsultaPublicaBuscaControle.php?transacao=CONSULTA&vara=2673';

$curl = curl_init($url);
@curl_setopt($curl, CURLOPT_POSTFIELDS, "foo");
@curl_setopt($curl, CURLOPT_FOLLOWLOCATION, true);
@curl_setopt($curl, CURLOPT_CUSTOMREQUEST, "POST");;

$html=@curl_exec($curl);

if (!$html) {
    echo "<br />cURL error number:" .curl_errno($curl);
    echo "<br />cURL error:" . curl_error($curl);
    exit;
}
else{
   echo '<br>begin HTML[';
    echo  $html;
   echo '<br>]end html ';
}
echo '</body></html>';

// Output
// 1

third attempt

function curl($url){
    $ch = curl_init();
    curl_setopt($ch, CURLOPT_URL, $url);
    curl_setopt($ch, CURLOPT_RETURNTRANSFER,1);
    curl_setopt($ch, CURLOPT_USERAGENT, 'Mozilla/5.0 (Windows NT 5.1) AppleWebKit/535.6 (KHTML, like Gecko) Chrome/16.0.897.0 Safari/535.6');
    curl_setopt($ch, CURLOPT_HEADER, true);
    curl_setopt($ch, CURLOPT_RETURNTRANSFER, true);
    curl_setopt($ch, CURLOPT_COOKIEFILE, "cookie.txt");
    curl_setopt($ch, CURLOPT_COOKIEJAR, "cookie.txt");
    curl_setopt($ch, CURLOPT_CONNECTTIMEOUT, 30);
    curl_setopt($ch, CURLOPT_REFERER, "http://www.windowsphone.com");

    $data = curl_exec($ch);
    curl_close($ch);
    return $data;
}

echo '<html><head></head><body>';
echo '<h1>Scraper PHP CURL 5</h1>';

// I used this url for test
//$url = 'http://www.portaldaadocao.com.br';

//This is the URL that I really want
$url = 'http://www.cnj.jus.br/cna/Controle/ConsultaPublicaBuscaControle.php?transacao=CONSULTA&vara=2673';

$curl = curl_init($url);
@curl_setopt($curl, CURLOPT_POSTFIELDS, "foo");
@curl_setopt($curl, CURLOPT_FOLLOWLOCATION, true);
@curl_setopt($curl, CURLOPT_CUSTOMREQUEST, "POST");;

$html=@curl($curl);


if (!$html) {
    echo "<br />cURL error number:" .curl_errno($curl);
    echo "<br />cURL error:" . curl_error($curl);
    exit;
}
else{
    echo '<br>begin HTML[';
    echo  $html;
    echo '<br>]end html ';
}
echo '</body></html>';

// Output
// cURL error number:0
// cURL error:

If the pages are really ajax based meaning the information that you need to scrape is loaded or shown through javascript execution, you will need another approach. You would need to automate with a real browser. You can go the Selenium route which can be written in a number of languages or use CasperJS with Javascript as the programming language.



Source: http://stackoverflow.com/questions/24611046/scraping-data-in-dynamic-sites

Thursday, 21 August 2014

Web Scraping data from different sites


I am looking for a few ideas on how can I solve a design problem I'm going to be faced with building a web scraper to scrape multiple sites. Writing the scraper(s) is not the problem, matching the data from different sites (which may have small differences) is.

For the sake of being generic assume that I am scraping something like this from two or more different sites:

    public class Data {
        public int id;
        public String firstname;
        public String surname;
        ....
    }

If i scrape this from two different sites, I will encounter the situation where I could have the following:

Site A: id=100, firstname=William, surname=Doe

Site B: id=1974, firstname=Bill, surname=Doe

Essentially, I would like to consider these two sets of data the same (they are the same person but with their name slightly different on each site). I am looking for possible design solutions that can handle this.

The only idea I've come up with is scraping the data from a third location and using it as a reference list. Then when I scrape site A or B I can, over time, build up a list of failures and store them in a list for each scraper so that it can know (if i find id=100 then i know that the firstname will be William etc). I can't help but feel this is a rubbish idea!

If you need any more info, or if you think my description is a bit naff, let me know!

Thanks,

DMcB


Source: http://stackoverflow.com/questions/23970057/web-scraping-data-from-different-sites

Wednesday, 20 August 2014

Scrape Data Point Using Python


I am looking to scrape a data point using Python off of the url http://www.cavirtex.com/orderbook .

The data point I am looking to scrape is the lowest bid offer, which at the current moment looks like this:

<tr>
 <td><b>Jan. 19, 2014, 2:37 a.m.</b></td>
 <td><b>0.0775/0.1146</b></td>
 <td><b>860.00000</b></td>
 <td><b>66.65 CAD</b></td>
</tr>

The relevant point being the 860.00 . I am looking to build this into a script which can send me an email to alert me of certain price differentials compared to other exchanges.

I'm quite noobie so if in your explanations you could offer your thought process on why you've done certain things it would be very much appreciated.

Thank you in advance!

Edit: This is what I have so far which will return me the name of the title correctly, I'm having trouble grabbing the table data though.

import urllib2, sys
from bs4 import BeautifulSoup

site= "http://cavirtex.com/orderbook"
hdr = {'User-Agent': 'Mozilla/5.0'}
req = urllib2.Request(site,headers=hdr)
page = urllib2.urlopen(req)
soup = BeautifulSoup(page)
print soup.title



Here is the code for scraping the lowest bid from the 'Buying BTC' table:

from selenium import webdriver

fp = webdriver.FirefoxProfile()
browser = webdriver.Firefox(firefox_profile=fp)
browser.get('http://www.cavirtex.com/orderbook')

lowest_bid = float('inf')
elements = browser.find_elements_by_xpath('//div[@id="orderbook_buy"]/table/tbody/tr/td')

for element in elements:
    text = element.get_attribute('innerHTML').strip('<b>|</b>')
    try:
        bid = float(text)
        if lowest_bid > bid:
            lowest_bid = bid
    except:
        pass

browser.quit()
print lowest_bid

In order to install Selenium for Python on your Windows-PC, run from a command line:

pip install selenium (or pip install selenium --upgrade if you already have it).

If you want the 'Selling BTC' table instead, then change "orderbook_buy" to "orderbook_sell".

If you want the 'Last Trades' table instead, then change "orderbook_buy" to "orderbook_trades".

Note:

If you consider performance critical, then you can implement the data-scraping via URL-Connection instead of Selenium, and have your program running much faster. However, your code will probably end up being a lot "messier", due to the tedious XML parsing that you'll be obliged to apply...

Here is the code for sending the previous output in an email from yourself to yourself:

import smtplib,ssl

def SendMail(username,password,contents):
    server = Connect(username)
    try:
        server.login(username,password)
        server.sendmail(username,username,contents)
    except smtplib.SMTPException,error:
        Print(error)
    Disconnect(server)

def Connect(username):
    serverName = username[username.index("@")+1:username.index(".")]
    while True:
        try:
            server = smtplib.SMTP(serverDict[serverName])
        except smtplib.SMTPException,error:
            Print(error)
            continue
        try:
            server.ehlo()
            if server.has_extn("starttls"):
                server.starttls()
                server.ehlo()
        except (smtplib.SMTPException,ssl.SSLError),error:
            Print(error)
            Disconnect(server)
            continue
        break
    return server

def Disconnect(server):
    try:
        server.quit()
    except smtplib.SMTPException,error:
        Print(error)

serverDict = {
    "gmail"  :"smtp.gmail.com",
    "hotmail":"smtp.live.com",
    "yahoo"  :"smtp.mail.yahoo.com"
}

SendMail("your_username@your_provider.com","your_password",str(lowest_bid))

The above code should work if your email provider is either gmail or hotmail or yahoo.

Please note that depending on your firewall configuration, it may ask your permission upon the first time you try it...



Source: http://stackoverflow.com/questions/21217034/scrape-data-point-using-python

Sunday, 17 August 2014

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