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

Friday, 22 August 2014

What is the right way of storing screen-scraping data?

i'm working on a web site. it is scraping product details(names, features, prices etc.) from various web sites, processing and displaying them. i'am considering to run update script on each day and keep data fresh.

    scrape data
    process them
    store on database
    read(from db) and display them

i'am already storing all the data in a sql schema but i'm not sure. After each update, all the old records are vanishing. if the scraped new data comes corrupted somehow, there is nothing to show.

so, is there any common way to archive the old data? which one is more convenient: seperate sql schemas or xml files? or something else?

Source: http://stackoverflow.com/questions/13686474/what-is-the-right-way-of-storing-screen-scraping-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

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

How to prevent data-scraping a valuable data web service?

I have a great idea for a windows store app. I'd like to make this app. However it requires a large and valuable database that I will need to create a service for so that people cannot easily steal it. My thinking is maybe host a mobile service on Azure (which I've never tried) and create a .net Web API project to take requests and dish out Json like candy to a windows 8 mvvmclient. However what I don't want is someone sniffing my traffic back and forth from app to service and figuring out how to get/post data from using my app and service then setting up their own app / website to display this data using my bandwidth to make them money.

How can I protect my app-to-db data access so it can't be reverse engineered on me.
Also is this the best setup for developing a high volume windows 8 app like this? Do you have a better suggestion?

EDIT: I know I can use SSL etc to encrypt traffic to and from. What I am trying to protect is someone using Firebug or Fiddler to figure out what parameters can be posted to get a particular record back. Then creating their own site that simply uses my service as the end point and siphons my data and whores my bandwidth. ie. Just using firebug I know I can use https://www.google.com/search?q=dallas to search the word dallas on google. Even if I encrypt the page, they can see that much in their browser. so if someone does the same get/post in their own application they would get the same records back thus using my stuff.

3 Answers

The most straight forward thing you can do is to setup authentication for your users using something like OAuth. This will allow you to ensure no communication happens with your service in an anonymous fashion.

Once you have authenticated your requests you can place controls on those requests that won't impact a normal user. You could rate limit or throttle requests or any number of tactics to make it very expensive time wise to siphon off large portions of your data set.

For instance, you can start blocking requests when you notice a large number of users clustering from a single IP address. You could place sensible limits on each user (like 10 API calls per minute with a result set limited to 50). You get the idea I'm sure.

I think we met the same concern. I'm developing a windows 8 application which is contacting a web service built on top of Windows Azure Web Site. I don't want the bad guy fire some fake requests to my service by intercepting the traffic through some tools like Fiddler.

I asked this question in a mail group and got a tip. I've never tried but just for your information. If your application needs user login, then the user's password is a good seed for data/traffic protection. You can use the password to generate a key-pair, sign the request and send it to server as well as the public key. Then on the server side it can verify the sign by the public key.

Use HTTPS is another approach. But as you know, a bad guy can also know the actual data through Fiddler even though HTTPS.

Use certificate might be another solution I think. But I didn't find the relevant document on how to install and pick a certificate from client's machine.

HTH

just serve it over HTTPS, then they can't sniff it.

Source:http://stackoverflow.com/questions/14350298/how-to-prevent-data-scraping-a-valuable-data-web-service

Wednesday, 13 August 2014

Business Intelligence Data Mining

Data mining can be technically defined as the automated extraction of hidden information from large databases for predictive analysis. In other words, it is the retrieval of useful information from large masses of data, which is also presented in an analyzed form for specific decision-making.

Data mining requires the use of mathematical algorithms and statistical techniques integrated with software tools. The final product is an easy-to-use software package that can be used even by non-mathematicians to effectively analyze the data they have. Data Mining is used in several applications like market research, consumer behavior, direct marketing, bioinformatics, genetics, text analysis, fraud detection, web site personalization, e-commerce, healthcare, customer relationship management, financial services and telecommunications.

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Business intelligence is a broader arena of decision-making that uses data mining as one of the tools. In fact, the use of data mining in BI makes the data more relevant in application. There are several kinds of data mining: text mining, web mining, social networks data mining, relational databases, pictorial data mining, audio data mining and video data mining, that are all used in business intelligence applications.

Some data mining tools used in BI are: decision trees, information gain, probability, probability density functions, Gaussians, maximum likelihood estimation, Gaussian Baves classification, cross-validation, neural networks, instance-based learning /case-based/ memory-based/non-parametric, regression algorithms, Bayesian networks, Gaussian mixture models, K-means and hierarchical clustering, Markov models and so on.

Source:http://ezinearticles.com/?Business-Intelligence-Data-Mining&id=196648