Monday, 30 September 2013

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/

Sunday, 29 September 2013

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/

Friday, 27 September 2013

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/

Thursday, 26 September 2013

Using External Input Data in Off-the-shelf Web Scrapers

There is a question I’ve wanted to shed some light upon for a long time already: “What if I need to scrape several URL’s based on data in some external database?“.

For example, recently one of our visitors asked a very good question (thanks, Ed):

    “I have a large list of amazon.com asin. I would like to scrape 10 or so fields for each asin. Is there any web scraping software available that can read each asin from a database and form the destination url to be scraped like http://www.amazon.com/gp/product/{asin} and scrape the data?”

This question impelled me to investigate this matter. I contacted several web scraper developers, and they kindly provided me with detailed answers that allowed me to bring the following summary to your attention:
Visual Web Ripper

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. You can find the additional information here.
Web Content Extractor

You can use the -at”filename” command line option to add new URLs from TXT or CSV file:

    WCExtractor.exe projectfile -at”filename” -s

projectfile: the file name of the project (*.wcepr) to open.
filename – the file name of the CSV or TXT file that contains URLs separated by newlines.
-s – starts the extraction process

You can find some options and examples here.
Mozenda

Since Mozenda is cloud-based, the external data needs to be loaded up into the user’s Mozenda account. That data can then be easily used as part of the data extracting process. You can construct URLs, search for strings that match your inputs, or carry through several data fields from an input collection and add data to it as part of your output. The easiest way to get input data from an external source is to use the API to populate data into a Mozenda collection (in the user’s account). You can also input data in the Mozenda web console by importing a .csv file or importing one through our agent building tool.

Once the data is loaded into the cloud, you simply initiate building a Mozenda web agent and refer to that Data list. By using the Load page action and the variable from the inputs, you can construct a URL like http://www.amazon.com/gp/product/%asin%.
Helium Scraper

Here is a video showing how to do this with Helium Scraper:

The video shows how to use the input data as URLs and as search terms. There are many other ways you could use this data, way too many to fit in a video. Also, if you know SQL, you could run a query to get the data directly from an external MS Access database like
SELECT * FROM [MyTable] IN "C:\MyDatabase.mdb"

Note that the database needs to be a “.mdb” file.
WebSundew Data Extractor
Basically this allows using input data from external data sources. This may be CSV, Excel file or a Database (MySQL, MSSQL, etc). Here you can see how to do this in the case of an external file, but you can do it with a database in a similar way (you just need to write an SQL script that returns the necessary data).
In addition to passing URLs from the external sources you can pass other input parameters as well (input fields, for example).
Screen Scraper

Screen Scraper is really designed to be interoperable with all sorts of databases. We have composed a separate article where you can find a tutorial and a sample project about scraping Amazon products based on a list of their ASINs.

Source: http://extract-web-data.com/using-external-input-data-in-off-the-shelf-web-scrapers/

Wednesday, 25 September 2013

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/

Tuesday, 24 September 2013

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/

Monday, 23 September 2013

Every Business Organization Needs Data Entry Services

Data entry is the main component of any business firm. They use this to maintain records of all sorts in a properly way. Although it seems to be an easier task but this is not the scenario, the work has to be done very cautiously and efficiently by the professional as data is very crucial. Data is priceless for any organization irrespective of their size and strength. Today, huge changes in the business industry have taken place and so businesses are adopting such new advanced techniques. These high end technologies have helped the data entry services in becoming much easier and efficient than ever before. If you are seeking to this service then must be prepared to spend more for this. So hiring this service will certainly help your business towards upward growth. Well, being the owner of your business, you are the best person to judge what will be a good strategy for your business. You can either hire a professional or can hire an outside firm to assist your data entry services task.

The newer methods of data entry services have over lapped the older and traditional methods of this service. Earlier, this service was done manually and obviously in-accuracy was found much more. So, information technology enabled services have come up with the new process that has made this service highly accurate and much easier. Indeed, every business wants to deal with this service very efficiently and accurately and so many have taken this highly enabled service for their firm. Data entry services are the key aspect of any business organization and every business needs a proper system to maintain its data and records. As data is crucial aspect of any firm irrespective of specialization or size and so they are in need of such an efficient system that can undertake their task.

An in-house data entry services would be more advantageous as you can keep a watch on the task done by professional. You can look into the procedure and other stuff that they do for your business. This can be bit expensive for your business as you will have to pay more as being an employee they are eligible for bonuses, allowances and other stuffs. If you are not satisfied with this option then you can undertake the services of a third party vendor. You can hand-over your entire task of data entry to them and can relieve of getting an efficient services. This can truly relieve you of getting a better service from them as you can get your task done in the way you desire. This option has proved to be more advantageous and proficient for many businesses. Now a day's data conversion process is highly accessed by many business firms and so gaining momentum on a large scale.

Data conversion is being done without any hassle and brings more customers to buy the products. Outsourcing of data entry services has seen huge success and businesses have seen huge profits through this service. This service has proved as a cost effective business strategy for businesses and have seen huge surge in their revenue.So, it's quite obvious that hiring data entry services from a third party vendor is better for the business then why to hire an in-house professional.





Source: http://ezinearticles.com/?Every-Business-Organization-Needs-Data-Entry-Services&id=596342