Web Scraper Shortcode WordPress Plugin Review

This short post is on the WP-plugin called Web Scraper Shortcode, that enables one to retrieve a portion of a web page or a whole page and insert it directly into a post. This plugin might be used for getting fresh data or images from web pages for your WordPress driven page without even visiting it. More scraping plugins and sowtware you can find in here.

To install it in WordPress go to Plugins -> Add New.
Usage

The plugin scrapes the page content and applies parameters to this scraped page if specified. To use the plugin just insert the

[web-scraper ]

shortcode into the HTML view of the WordPress page where you want to display the excerpts of a page or the whole page. The parameters are as follows:

    url (self explanatory)
    element – the dom navigation element notation, similar to XPath.
    limit – the maximum number of elements to be scraped and inserted if the element notation points to several of them (like elements of the same class).

The use of the plugin is of the dom (Data Object Model) notation, where consecutive dom nodes are stated like node1.node2; for example: element = ‘div.img’. The specific element scrape goes thru ‘#notation’. Example: if you want to scrape several ‘div’ elements of the class ‘red’ (<div class=’red’>…<div>), you need to specify the element attribute this way: element = ‘div#red’.
How to find DOM notation?

But for inexperienced users, how is it possible to find the dom notation of the desired element(s) from the web page? Web Developer Tools are a handy means for this. I would refer you to this paragraph on how to invoke Web Developer Tools in the browser (Google Chrome) and select a single page element to inspect it. As you select it with the ‘loupe’ tool, on the bottom line you’ll see the blue box with the element’s dom notation:


The plugin content

As one who works with web scraping, I was curious about  the means that the plugin uses for scraping. As I looked at the plugin code, it turned out that the plugin acquires a web page through ‘simple_html_dom‘ class:

    require_once(‘simple_html_dom.php’);
    $html = file_get_html($url);
    then the code performs iterations over the designated elements with the set limit

Pitfalls

    Be careful if you put two or more [web-scraper] shortcodes on your website, since downloading other pages will drastically slow the page load speed. Even if you want only a small element, the PHP engine first loads the whole page and then iterates over its elements.
    You need to remember that many pictures on the web are indicated by shortened URLs. So when such an image gets extracted it might be visible to you in this way: , since the URL is shortened and the plugin does not take note of  its base URL.
    The error “Fatal error: Call to a member function find() on a non-object …” will occur if you put this shortcode in a text-overloaded post.

Summary

I’d recommend using this plugin for short posts to be added with other posts’ elements. The use of this plugin is limited though.



Source: http://extract-web-data.com/web-scraper-shortcode-wordpress-plugin-review/

Microsys A1 Website Scraper Review

The A1 scraper by Microsys is a program that is mainly used to scrape websites to extract data in large quantities for later use in webservices. The scraper works to extract text, URLs etc., using multiple Regexes and saving the output into a CSV file. This tool is can be compared with other web harvesting and web scraping services.
How it works
This scraper program works as follows:
Scan mode

    Go to the ScanWebsite tab and enter the site’s URL into the Path subtab.
    Press the ‘Start scan‘ button to cause the crawler to find text, links and other data on this website and cache them.

Important: URLs that you scrape data from have to pass filters defined in both analysis filters and output filters. The defining of those filters can be set at the Analysis filters and Output filters subtabs respectively. They must be set at the website analysis stage (mode).
Extract mode

    Go to the Scraper Options tab
    Enter the Regex(es) into the Regex input area.
    Define the name and path of the output CSV file.
    The scraper automatically finds and extracts the data according to Regex patterns.

The result will be stored in one CSV file for all the given URLs.

There is a need to mention that the set of regular expressions will be run against all the pages scraped.
Some more scraper features

Using the scraper as a website crawler also affords:

    URL filtering.
    Adjustment of the speed of crawling according to service needs rather than server load.

If  you need to extract data from a complex website, just disable Easy mode: out press the  button. A1 Scraper’s full tutorial is available here.
Conclusion

The A1 Scraper is good for mass gathering of URLs, text, etc., with multiple conditions set. However this scraping tool is designed for using only Regex expressions, which can increase the parsing process time greatly.



Source: http://extract-web-data.com/microsys-a1-website-scraper-review/

Visual Web Ripper: Using External Input Data Sources

Sometimes it is necessary to use external data sources to provide parameters for the scraping process. For example, you have a database with a bunch of ASINs and you need to scrape all product information for each one of them. As far as Visual Web Ripper is concerned, an input data source can be used to provide a list of input values to a data extraction project. A data extraction project will be run once for each row of input values.

An input data source is normally used in one of these scenarios:

    To provide a list of input values for a web form
    To provide a list of start URLs
    To provide input values for Fixed Value elements
    To provide input values for scripts

Visual Web Ripper supports the following input data sources:

    SQL Server Database
    MySQL Database
    OleDB Database
    CSV File
    Script (A script can be used to provide data from almost any data source)

To see it in action you can download a sample project that uses an input CSV file with Amazon ASIN codes to generate Amazon start URLs and extract some product data. Place both the project file and the input CSV file in the default Visual Web Ripper project folder (My Documents\Visual Web Ripper\Projects).

For further information please look at the manual topic, explaining how to use an input data source to generate start URLs.


Source: http://extract-web-data.com/visual-web-ripper-using-external-input-data-sources/

A simple way to turn a website into JSON

Recently, while surfing the web I stumbled upon an simple web scraping service named Web Scrape Master. It is a kind of RESTful web service that extracts data from a specified web site and returns it to you in JSON format.
How it works

Though I don’t know what this service may be useful for, I still like its simplicity: all you need to do is to make an HTTP GET request, passing all necessary parameters in the query string:
http://webscrapemaster.com/api/?url={url}&xpath={xpath}&attr={attr}&callback={callback}

    url  - the URL of the website you want to scrape
    xpath – xpath determining the data you need to extract
    attr - attribute the name you need to get the value of (optional)
    callback - JSON callback function (optional)

For example, for the following request to our testing ground:

http://webscrapemaster.com/api/?url=http://testing-ground.extract-web-data.com/blocks&xpath=//div[@id=case1]/div[1]/span[1]/div

You will get the following response:

[{"text":"<div class='name'>Dell Latitude D610-1.73 Laptop Wireless Computer</div>","attrs":{"class":"name"}}]
Visual Web Scraper

Also, this service offers a special visual tool for building such requests. All you need to do is to enter the URL of the website and click to the element you need to scrape:
Visual Web Scraper
Conclusion

Though I understand that the developer of this service is attempting to create a simple web scraping service, it is still hard to imagine where it can be useful. The task that the service does can be easily accomplished by means of any language.

Probably if you already have software receiving JSON from the web, and you want to feed it with data from some website, then you may find this service useful. The other possible application is to hide your IP when you do web scraping. If you have other ideas, it would be great if you shared them with us.



Source: http://extract-web-data.com/a-simple-way-to-turn-a-website-into-json/

Selenium IDE and Web Scraping

Selenium is a browser automation framework that includes IDE, Remote Control server and bindings of various flavors including Java, .Net, Ruby, Python and other. In this post we touch on the basic structure of the framework and its application to  Web Scraping.
What is Selenium IDE


Selenium IDE is an integrated development environment for Selenium scripts. It is implemented as a Firefox plugin, and it allows recording browsers’ interactions in order to edit them. This works well for software tests, composing and debugging. The Selenium Remote Control is a server specific for a particular environment; it causes custom scripts to be implemented for controlled browsers. Selenium deploys on Windows, Linux, and iOS. How various Selenium components are supported with major browsers read here.
What does Selenium do and Web Scraping

Basically Selenium automates browsers. This ability is no doubt to be applied to web scraping. Since browsers (and Selenium) support JavaScript, jQuery and other methods working with dynamic content why not use this mix for benefit in web scraping, rather than to try to catch Ajax events with plain code? The second reason for this kind of scrape automation is browser-fasion data access (though today this is emulated with most libraries).

Yes, Selenium works to automate browsers, but how to control Selenium from a custom script to automate a browser for web scraping? There are Selenium PHP and other language libraries (bindings) providing for scripts to call and use Selenium. It is possible to write Selenium clients (using the libraries) in almost any language we prefer, for example Perl, Python, Java, PHP etc. Those libraries (API), along with a server, the Java written server that invokes browsers for actions, constitute the Selenum RC (Remote Control). Remote Control automatically loads the Selenium Core into the browser to control it. For more details in Selenium components refer to here.



A tough scrape task for programmer

“…cURL is good, but it is very basic.  I need to handle everything manually; I am creating HTTP requests by hand.
This gets difficult – I need to do a lot of work to make sure that the requests that I send are exactly the same as the requests that a browser would
send, both for my sake and for the website’s sake. (For my sake
because I want to get the right data, and for the website’s sake
because I don’t want to cause error messages or other problems on their site because I sent a bad request that messed with their web application).  And if there is any important javascript, I need to imitate it with PHP.
It would be a great benefit to me to be able to control a browser like Firefox with my code. It would solve all my problems regarding the emulation of a real browser…
it seems that Selenium will allow me to do this…” -Ryan S

Yes, that’s what we will consider below.
Scrape with Selenium

In order to create scripts that interact with the Selenium Server (Selenium RC, Selenium Remote Webdriver) or create local Selenium WebDriver script, there is the need to make use of language-specific client drivers (also called Formatters, they are included in the selenium-ide-1.10.0.xpi package). The Selenium servers, drivers and bindings are available at Selenium download page.
The basic recipe for scrape with Selenium:

    Use Chrome or Firefox browsers
    Get Firebug or Chrome Dev Tools (Cntl+Shift+I) in action.
    Install requirements (Remote control or WebDriver, libraries and other)
    Selenium IDE : Record a ‘test’ run thru a site, adding some assertions.
    Export as a Python (other language) script.
    Edit it (loops, data extraction, db input/output)
    Run script for the Remote Control

The short intro Slides for the scraping of tough websites with Python & Selenium are here (as Google Docs slides) and here (Slide Share).
Selenium components for Firefox installation guide

For how to install the Selenium IDE to Firefox see  here starting at slide 21. The Selenium Core and Remote Control installation instructions are there too.
Extracting for dynamic content using jQuery/JavaScript with Selenium

One programmer is doing a similar thing …

1. launch a selenium RC (remote control) server
2. load a page
3. inject the jQuery script
4. select the interested contents using jQuery/JavaScript
5. send back to the PHP client using JSON.

He particularly finds it quite easy and convenient to use jQuery for
screen scraping, rather than using PHP/XPath.
Conclusion

The Selenium IDE is the popular tool for browser automation, mostly for its software testing application, yet also in that Web Scraping techniques for tough dynamic websites may be implemented with IDE along with the Selenium Remote Control server. These are the basic steps for it:

    Record the ‘test‘ browser behavior in IDE and export it as the custom programming language script
    Formatted language script runs on the Remote Control server that forces browser to send HTTP requests and then script catches the Ajax powered responses to extract content.

Selenium based Web Scraping is an easy task for small scale projects, but it consumes a lot of memory resources, since for each request it will launch a new browser instance.



Source: http://extract-web-data.com/selenium-ide-and-web-scraping/

Data Recovery Services - Be Wary of Cheap Prices

Data recovery is a specialized, complicated process. Proper hard drive recovery can require manipulation of data at the sector level, transplantation of internal components and various other procedures. These techniques are very involved and require not only talented, knowledgeable technicians, but also an extensive inventory of disk drives to use for parts when necessary and clean facilities to conduct the work.

Unfortunately these factors mean that, in most cases, recovery services are quite expensive. Technician training, hard drive inventories and special equipment all come with a cost.

If you search for disk recovery services, you will likely find several smaller companies that offer hard disk data recovery for a fraction of the prices usually quoted by larger, more experienced organizations. These companies often operate from small offices or, in some cases, private homes. They do not possess clean room facilities, large disk drive inventories or many other pieces of equipment necessary to successfully complete most hard drive recovery cases.

When you take into account all of the training, parts and facilities necessary, you can see how it is impossible for a company to charge $200 for a hard drive recovery and not operate at a loss.

What these companies usually do is run a software program on the hard disk drive. Sometimes, if there is no physical damage to the disk drive, this program is able to recover some of the data. However, hard disk data recovery is much more than just running software. No software can recover data from a hard drive that has failed heads, damaged platters or electrical damage. In fact, attempting to run a hard drive that is physically damaged can make the problem worse. Trying to use software to recover data from a hard drive with failed read/write heads, for example, can lead to the heads scraping the platters of the drive and leaving the data unrecoverable.

Another way these smaller companies conduct business is by forwarding data recovery cases they cannot recover to larger organizations. Of course, the smaller companies charge their clients a premium for this service. In these cases it would have actually been cheaper to use the larger company in the first place.

You will also likely find that many smaller recovery companies charge evaluation or diagnostic fees upfront. They charge these fees regardless of whether or not any data is recovered. In many cases clients desperate to recover their data pay these fees and get nothing in return but a failed recovery. Smaller data recovery services simply do not have the skills, training, facilities and parts to successfully recover most disk drives. It is more cost efficient for them to make one attempt at running a software program and then call the case unsuccessful.

Sometimes you may get lucky working with a smaller data recovery company, but in most cases you will end up paying for a failed recovery. In the worst case scenario you could end up with a damaged hard drive that is now unrecoverable by any data recovery service.

You will waste time and money working with these services. You could even lose your valuable data for good.

If your data is important enough to consider data recovery, it is important enough to seek a reputable, skilled data recovery company. All major data recovery services offer free evaluations and most do not charge clients for unsuccessful recoveries. Sometimes you only have one shot to recover data on a disk drive before the platters are seriously damaged and the data is lost for good. Taking chances with inexperienced companies is not worth the risk.

The Data Recovery Services, part of ACE Data Group, specializes in recovering data from corrupted RAID/SAN/NAS systems, hard drives, CD/DVD, solid state drives, tapes and proprietary devices. Logical recovery expertise is in whole spectrum of file systems and reverse engineering, experts in hard drive recovery and RAID data recovery services.




Source: http://ezinearticles.com/?Data-Recovery-Services---Be-Wary-of-Cheap-Prices&id=4706055

Limitations and Challenges in Effective Web Data Mining

Web data mining and data collection is critical process for many business and market research firms today. Conventional Web data mining techniques involve search engines like Google, Yahoo, AOL, etc and keyword, directory and topic-based searches. Since the Web's existing structure cannot provide high-quality, definite and intelligent information, systematic web data mining may help you get desired business intelligence and relevant data.

Factors that affect the effectiveness of keyword-based searches include:
• Use of general or broad keywords on search engines result in millions of web pages, many of which are totally irrelevant.
• Similar or multi-variant keyword semantics my return ambiguous results. For an instant word panther could be an animal, sports accessory or movie name.
• It is quite possible that you may miss many highly relevant web pages that do not directly include the searched keyword.

The most important factor that prohibits deep web access is the effectiveness of search engine crawlers. Modern search engine crawlers or bot can not access the entire web due to bandwidth limitations. There are thousands of internet databases that can offer high-quality, editor scanned and well-maintained information, but are not accessed by the crawlers.

Almost all search engines have limited options for keyword query combination. For example Google and Yahoo provide option like phrase match or exact match to limit search results. It demands for more efforts and time to get most relevant information. Since human behavior and choices change over time, a web page needs to be updated more frequently to reflect these trends. Also, there is limited space for multi-dimensional web data mining since existing information search rely heavily on keyword-based indices, not the real data.

Above mentioned limitations and challenges have resulted in a quest for efficiently and effectively discover and use Web resources. Send us any of your queries regarding Web Data mining processes to explore the topic in more detail.



Source: http://ezinearticles.com/?Limitations-and-Challenges-in-Effective-Web-Data-Mining&id=5012994