Three Common Methods For Web Data Extraction

Three Common Methods For Web Data Extraction

Probably the most common technique used traditionally to extract data from web pages this is to cook up some regular expressions that match the pieces you want (e.g., URL's and link titles). Our screen-scraper software actually started out as an application written in Perl for this very reason. In addition to regular expressions, you might also use some code written in something like Java or Active Server Pages to parse out larger chunks of text. Using raw regular expressions to pull out the data can be a little intimidating to the uninitiated, and can get a bit messy when a script contains a lot of them. At the same time, if you're already familiar with regular expressions, and your scraping project is relatively small, they can be a great solution.

Other techniques for getting the data out can get very sophisticated as algorithms that make use of artificial intelligence and such are applied to the page. Some programs will actually analyze the semantic content of an HTML page, then intelligently pull out the pieces that are of interest. Still other approaches deal with developing "ontologies", or hierarchical vocabularies intended to represent the content domain.

There are a number of companies (including our own) that offer commercial applications specifically intended to do screen-scraping. The applications vary quite a bit, but for medium to large-sized projects they're often a good solution. Each one will have its own learning curve, so you should plan on taking time to learn the ins and outs of a new application. Especially if you plan on doing a fair amount of screen-scraping it's probably a good idea to at least shop around for a screen-scraping application, as it will likely save you time and money in the long run.

So what's the best approach to data extraction? It really depends on what your needs are, and what resources you have at your disposal. Here are some of the pros and cons of the various approaches, as well as suggestions on when you might use each one:

Raw regular expressions and code

Advantages:

- If you're already familiar with regular expressions and at least one programming language, this can be a quick solution.

- Regular expressions allow for a fair amount of "fuzziness" in the matching such that minor changes to the content won't break them.

- You likely don't need to learn any new languages or tools (again, assuming you're already familiar with regular expressions and a programming language).

- Regular expressions are supported in almost all modern programming languages. Heck, even VBScript has a regular expression engine. It's also nice because the various regular expression implementations don't vary too significantly in their syntax.

Disadvantages:

- They can be complex for those that don't have a lot of experience with them. Learning regular expressions isn't like going from Perl to Java. It's more like going from Perl to XSLT, where you have to wrap your mind around a completely different way of viewing the problem.

- They're often confusing to analyze. Take a look through some of the regular expressions people have created to match something as simple as an email address and you'll see what I mean.

- If the content you're trying to match changes (e.g., they change the web page by adding a new "font" tag) you'll likely need to update your regular expressions to account for the change.

- The data discovery portion of the process (traversing various web pages to get to the page containing the data you want) will still need to be handled, and can get fairly complex if you need to deal with cookies and such.

When to use this approach: You'll most likely use straight regular expressions in screen-scraping when you have a small job you want to get done quickly. Especially if you already know regular expressions, there's no sense in getting into other tools if all you need to do is pull some news headlines off of a site.

Ontologies and artificial intelligence

Advantages:

- You create it once and it can more or less extract the data from any page within the content domain you're targeting.

- The data model is generally built in. For example, if you're extracting data about cars from web sites the extraction engine already knows what the make, model, and price are, so it can easily map them to existing data structures (e.g., insert the data into the correct locations in your database).

- There is relatively little long-term maintenance required. As web sites change you likely will need to do very little to your extraction engine in order to account for the changes.

Disadvantages:

- It's relatively complex to create and work with such an engine. The level of expertise required to even understand an extraction engine that uses artificial intelligence and ontologies is much higher than what is required to deal with regular expressions.

- These types of engines are expensive to build. There are commercial offerings that will give you the basis for doing this type of data extraction, but you still need to configure them to work with the specific content domain you're targeting.

- You still have to deal with the data discovery portion of the process, which may not fit as well with this approach (meaning you may have to create an entirely separate engine to handle data discovery). Data discovery is the process of crawling web sites such that you arrive at the pages where you want to extract data.

When to use this approach: Typically you'll only get into ontologies and artificial intelligence when you're planning on extracting information from a very large number of sources. It also makes sense to do this when the data you're trying to extract is in a very unstructured format (e.g., newspaper classified ads). In cases where the data is very structured (meaning there are clear labels identifying the various data fields), it may make more sense to go with regular expressions or a screen-scraping application.

Screen-scraping software

Advantages:

- Abstracts most of the complicated stuff away. You can do some pretty sophisticated things in most screen-scraping applications without knowing anything about regular expressions, HTTP, or cookies.

- Dramatically reduces the amount of time required to set up a site to be scraped. Once you learn a particular screen-scraping application the amount of time it requires to scrape sites vs. other methods is significantly lowered.

- Support from a commercial company. If you run into trouble while using a commercial screen-scraping application, chances are there are support forums and help lines where you can get assistance.

Disadvantages:

- The learning curve. Each screen-scraping application has its own way of going about things. This may imply learning a new scripting language in addition to familiarizing yourself with how the core application works.

- A potential cost. Most ready-to-go screen-scraping applications are commercial, so you'll likely be paying in dollars as well as time for this solution.

- A proprietary approach. Any time you use a proprietary application to solve a computing problem (and proprietary is obviously a matter of degree) you're locking yourself into using that approach. This may or may not be a big deal, but you should at least consider how well the application you're using will integrate with other software applications you currently have. For example, once the screen-scraping application has extracted the data how easy is it for you to get to that data from your own code?

When to use this approach: Screen-scraping applications vary widely in their ease-of-use, price, and suitability to tackle a broad range of scenarios. Chances are, though, that if you don't mind paying a bit, you can save yourself a significant amount of time by using one. If you're doing a quick scrape of a single page you can use just about any language with regular expressions. If you want to extract data from hundreds of web sites that are all formatted differently you're probably better off investing in a complex system that uses ontologies and/or artificial intelligence. For just about everything else, though, you may want to consider investing in an application specifically designed for screen-scraping.

As an aside, I thought I should also mention a recent project we've been involved with that has actually required a hybrid approach of two of the aforementioned methods. We're currently working on a project that deals with extracting newspaper classified ads. The data in classifieds is about as unstructured as you can get. For example, in a real estate ad the term "number of bedrooms" can be written about 25 different ways. The data extraction portion of the process is one that lends itself well to an ontologies-based approach, which is what we've done. However, we still had to handle the data discovery portion. We decided to use screen-scraper for that, and it's handling it just great. The basic process is that screen-scraper traverses the various pages of the site, pulling out raw chunks of data that constitute the classified ads. These ads then get passed to code we've written that uses ontologies in order to extract out the individual pieces we're after. Once the data has been extracted we then insert it into a database.

Source: http://ezinearticles.com/?Three-Common-Methods-For-Web-Data-Extraction&id=165416

Web Scraping Best Practices

Web Scraping Best Practices

Extracting data from the World Wide Web has several challenges as more webmasters are working day and night to lower cases of scraping and crawling of their data in order to survive in the competitive world. There are various other problems you may face when web scraping and most of them can be avoided by adapting and implementing certain web scraping best practices as discussed in this article.

Have knowledge of the scraping tools

Acquiring adequate knowledge of hurdles that may be encountered during web scraping, you will be able to have a smooth web scraping experience and be on the safe side of the law. Conduct a thorough research on the types of tools you will use for scraping and crawling. Firsthand knowledge on these tools will help you find the data you need without being blocked.

Proper proxy software that acts as the middle party works well when you know how to work around HTTP and HTML protocols. Use tools that can change crawling patterns, URLs and data retrieved even when you are crawling on one domain. This will help you abide to the rules and regulations that come with web scraping activities and escaping any legal issues.
Conduct your scraping activities during off-peak hours

You may opt to extract data during times that less people have access for instance over the weekends, during late night hours, public holidays among others. Visiting a website on several instances to retrieve the same type of data is a waste of bandwidth. It is always advisable to download the entire site content to your computer and thereafter you can access it whenever need arises.
Hide your scrapping activities

There is a thin line between ethical and unethical crawling hence you should completely evade being on the top user list of a particular website. Cover up your track as best as you can by making use of proxy IPs to avoid any legal problems. You may also use multiple IP addresses or VPN services to conceal your scrapping activities and lower chances of landing on a website’s blacklist.

Website owners today are very protective of their data and any other information existing under their unique url. Be keen when going through the terms and conditions indicated by websites as they may consider crawling as an infringement of their privacy. Simple etiquette goes a long way. Your web scraping efforts will be fruitful if the site owner supports the idea of sharing data.
Keep record of your activities

Web scraping involves large amount of data.Due to this you may not always remember each and every piece of information you have acquired, gathering statistics will help you monitor your activities.
Load data in phases

Web scraping demands a lot of patience from you when using the crawlers to get needed information. Take the process in a slow manner by loading data one piece at a time. Several parallel request to the same domain can crush the entire site or retrace the scrapping attempts back to your local machine.

Loading data small bits will save you the hustle of scrapping afresh in case that your activity has been interrupted because you will have already stored part of the data required. You can reduce the loading data on an individual domain through various techniques such as caching pages that you have scrapped to escape redundancy occurrences. Use auto throttling mechanisms to increase the amount of traffic to the website and pause for breaks between requests to prevent getting banned.
Conclusion

Through these few mentioned web scraping best practices you will be able to work around website and gather the data required as per clients’ request without major hurdles along the way. The ultimate goal of every web scraper is to be able to access vital information and at the same time remain on the good side of the law.

Source: http://nocodewebscraping.com/web-scraping-best-practices/

Data Discovery vs. Data Extraction

Data Discovery vs. Data Extraction

Looking at screen-scraping at a simplified level, there are two primary stages involved: data discovery and data extraction. Data discovery deals with navigating a web site to arrive at the pages containing the data you want, and data extraction deals with actually pulling that data off of those pages. Generally when people think of screen-scraping they focus on the data extraction portion of the process, but my experience has been that data discovery is often the more difficult of the two.

The data discovery step in screen-scraping might be as simple as requesting a single URL. For example, you might just need to go to the home page of a site and extract out the latest news headlines. On the other side of the spectrum, data discovery may involve logging in to a web site, traversing a series of pages in order to get needed cookies, submitting a POST request on a search form, traversing through search results pages, and finally following all of the "details" links within the search results pages to get to the data you're actually after. In cases of the former a simple Perl script would often work just fine. For anything much more complex than that, though, a commercial screen-scraping tool can be an incredible time-saver. Especially for sites that require logging in, writing code to handle screen-scraping can be a nightmare when it comes to dealing with cookies and such.

In the data extraction phase you've already arrived at the page containing the data you're interested in, and you now need to pull it out of the HTML. Traditionally this has typically involved creating a series of regular expressions that match the pieces of the page you want (e.g., URL's and link titles). Regular expressions can be a bit complex to deal with, so most screen-scraping applications will hide these details from you, even though they may use regular expressions behind the scenes.

As an addendum, I should probably mention a third phase that is often ignored, and that is, what do you do with the data once you've extracted it? Common examples include writing the data to a CSV or XML file, or saving it to a database. In the case of a live web site you might even scrape the information and display it in the user's web browser in real-time. When shopping around for a screen-scraping tool you should make sure that it gives you the flexibility you need to work with the data once it's been extracted.

Source: http://ezinearticles.com/?Data-Discovery-vs.-Data-Extraction&id=165396

Best Alternative For Linkedin Data Scraping

Best Alternative For Linkedin Data Scraping

When I started my career in sales, one of the things that my VP of sales told me is that ” In sales, assumptions are the mother of all f**k ups “. I know the F word sounds a bit inappropriate, but that is the exact word he used. He was trying to convey the simple point that every prospect is different, so don’t guess, use data to come up with decisions.

I joined Datahut and we are working on a product that helps sales people. I thought I should discuss it with you guys and take your feedback.

Let me tell you how the idea evolved itself. At Datahut, we get to hear a lot of problems customers want to solve. Almost 30 percent of all the inbound leads ask us to help them with lead generation.

Most of them simply ask, “Can you scrape Linkedin for me”?

Every time, we politely refused.

But not anymore, we figured out a way to solve their problem without scraping Linkedin.

This should raise some questions in your mind.

1) What problem is he trying to solve?– Most of the time their sales team does not have the accurate data about the prospects. This leads to a total chaos. It will end up in a waste of both time and money by selling the leads that are not sales qualified.

2) Why do they need data specifically from Linkedin? – LinkedIn is the world’s largest business network. In his view, there is no better place to find leads for his business than Linkedin. It is right in a way.

3) Ok, then what is wrong in scraping Linkedin? – Scraping Linkedin is against its terms and it can lead to legal issues. Linkedin has an excellent anti-scraping mechanism which can make the scraping costly.

4) How severe is the problem? – The problem has a direct impact on the revenues as the productivity of the sales team is too low. Without enough sales, the company is a joke.

5) Is there a better way? – Of course yes. The people with profiles in LinkedIn are in other sites too. eg. Google plus, CrunchBase etc. If we can mine and correlate the data, we can generate leads with rich information. It will have better quality than scraping LinkedIn.

6) What to do when the machine intelligence fails? – We have to use human intelligence. Period!

Datahut is working on a platform that can help you get leads that match your ideal buyer persona. It will be a complete Business intelligence platform powered by machine and human intelligence for an efficient lead research & discovery.We named it Leadintel. We’ve also established some partnerships that help to enrich the data and saves the trouble of lawsuits.

We are opening our platform for beta users. You can request an invitation using the contact form. What do you think about this? What are your suggestions?

Thanks for reading this blog post. Datahut offers affordable data extraction services (DaaS) . If you need help with your web scraping projects let us know and we will be glad to help.

Source:http://blog.datahut.co/best-alternative-for-linkedin-data-scraping/

Content Scrapers – How to Find Out Who is Stealing Your Content & What to Do About It

If you have been blogging for a while, chances are you are familiar with content scrapers. Content scrapers are websites that steal your content for their own blogs without your permission. Some content scrapers will just copy the content off of your blog, but most use automated software that takes the content from your RSS feed and posts your content to their site like it is a new post.

In this post, we are going to look at some potential link building benefits to content scrapers, how to find out what sites are scraping your content, and what you can do if you want to either benefit from the linking standpoint or have them take it down.

Linking Benefits of Content Scrapers

Last week, I was happy to see that I was listed in ProBlogger’s 20 Bloggers to Watch in 2012. Within 24 hours, I received a notification in my WordPress dashboard that a page on my blog had been linked to in the post on ProBlogger’s site.

After receiving the original notification from the ProBlogger post, I also received another 18 trackbacks from sites that had stolen the content in their post verbatim. Trackbacks are WordPress’ way of letting you know that another website has linked to a post on your blog. In this case, these 18 sites had posted the content exactly like the original post – with the links back to my blog still intact.

It was then that I started contemplating the potential link building benefits of content scrapers. These are not by any means quality links – the highest Google PageRank was a PR 2 domain, many were stealing content in a variety of languages, and one even had the nerve to use some kind of redirection script to take away the link juice of outgoing links! So while these links didn’t have the same authority that the original post had, they still count as links.

How to Catch Content Scrapers

Unfortunately, unless you want to continuously search for your post titles in Google, you’ll only be able to easily track down sites that keep your in-content links active. If you want to know what websites are scraping your content, here are a few tips to sniff them out.

Copyscape

Copyscape is a simple search engine that allows you to enter the URL of your content to find out if there are duplicates of it on the Internet. You can get a few results using their free search, or you can pay for a premium account to check up to 10,000 pages on your site and more.

Trackbacks

The first way is through your trackbacks in WordPress (as shown in the image above). Many of these will show up in the spam folder if you use Akismet. The key to getting trackbacks to appear from content scrapers is to always include links to other posts in your content. Be sure those links have great anchor text too, if you’re going for a little extra link juice. And even if you are not, internal linking with strong anchor text is good for your on-site optimization too!

Anyone thinking about link building benefits at this point is probably noting the sheer volume of links from these sites, some of which are content scrapers. Essentially any site that is linking to a lot of your posts that isn’t a social network, social bookmarking site, or a die-hard fan who just loves linking to you is potentially a content scraper. You’ll have to go to their website to be sure. To find your links on their site, click on one of the domains to see the details of what pages on your site they are linking to specifically.

You can see here that they are just blatantly copying my posts titles. When I visited one of the links, sure enough, they are copying my entire posts in their full glory onto their site.

Google Alerts

If you don’t post often or want to keep up with any mentions of your top blog posts on other websites, you can create a Google Alert using the exact match for your post’s title by putting the title in quotation marks.

I deliver all of my Google Alerts to an RSS feed so I can manage them in Google Reader, but you can also have them delivered regularly by email. You’ll even get an instant preview of the types of results you will get.

How to Get Credit for Scraped Posts

If you use WordPress, then you definitely want to try out the RSS footer plugin. This plugin allows you to place a custom piece of text at the top or bottom of your RSS feed content.
As you can see, even if you aren’t using it for the purpose of getting credit back to your posts when content thieves steal it, you can still use it for a little extra bit of advertising with the possible benefit of people who subscribe to your RSS feed clicking through to your website or social profiles. And when someone does scrape your content from your RSS feed, it shows up there too

So in the event that someone finds your scraped content, they will hopefully notice the credit before assuming it was created by the blog that stole it. If you don’t have WordPress, you can simply include a note at the top or bottom of your content that includes the same information.

How to Stop Content Scrapers

If you’re not interested in anyone copying your content, then you have a few options to choose from. You can start by contacting the site that is stealing your content and sending them a notice that you want all of your content removed immediately. You can do this through the site’s contact form, email address, or post it to any social accounts they list.

If there is no contact information on the website stealing your content, you can do a Whois Lookup to (hopefully) find out who owns the domain.

If it is not privately registered, you should find an administrative contact’s email address. If not, you should at least see the domain registrar which, in this case, is GoDaddy and/or the hosting company for the website which, in this case, is HostGator. You can try to contact both companies (HostGator has a DMCA form and GoDaddy has an email) and let them know that the domain in question is stealing copyrighted content in hopes that the website will be suspended or removed.

You can also visit the DMCA and use their takedown services to remove anyone who is copying your photos, video, audio, blog, or other content. They even offer a WordPress plugin to incorporate a DMCA protected badge on your site to warn potential thieves.

Have you ever dealt with content scrapers and thieves? Do you leave it alone for the link benefits, or do you fight back? What other tools, services, or other preventative tactics do you use to block content scrapers? Please share your thoughts and experiences in the comments!

Source URL : https://blog.kissmetrics.com/content-scrapers/

4 Web Scraping Tools To Save You Time On Data Extraction

Either you are working on a product website, struggling to add live data feed to your app or merely need to pull out a huge amount of online data for analysis, an accurate web scraping tool can save you loads of time and keep you sane. Here are four powerful web scraping tools to save you from copy-pasting or spending time on writing your own scripts.

Uipath  specializes in developing various process automation software including web scraping and screen scraping software for desktop and web. Uipath web scraper is perfect for non-coders and easily surpasses most common data extraction challenges including page navigation, digging through flash and even scraping PDF files. All you need to do is open the web scraping wizard and simply highlight the data you need to extract. The tool will scrape all the data following this pattern at all pages you’ve chosen and sort it accordingly. You can add as many items for scraping as you like and have them sorted in respective columns. As a result, you receive a neat Excel or CSV document with all the data eliminated from duplicates.

Moreover, Uipath isn’t just about scraping. This software can be used not only for extracting data, but to manipulate the interface of another app, thus establishing data transfers among the two of them. Basically, this tool could be used to conduct any repetitive task a human could do, yet much faster and with higher accuracy.

Pros: You can automate form filling, clicking buttons, navigation etc. Uipath scraper is impressively accurate, fast and simple to use. It “reads” all types of data on screen (JS, HTML, Silverlight and more), plus you can train the software to emulate human actions of various complexity.

Cons: Premium software runs at a premium price. Uipath is an affordable professional solution, but may be a bit too pricey for personal use.

 Import.io  offers you a free desktop app to help you scrap all the data you need from an unlimited amount of web pages. The service treats each page as a potential data source to generate API from. If the page you’ve submitted has been previously processed, you can access its API and get some of the data. In other case, Import.io will guide you through the process of creating the scraping matrix by building connectors (for navigation) or extractors (to pull out the needed data). Afterwards, you submit a request for extraction and it’s typically processed within 24 hours. All the data is private and you can schedule auto refreshments at any chosen period of time.

Pros: The service is easy-to-use with no tech skills needed. It can  pages with data (those that needed login/pass), plus it’s free. Minimalistic effective design and simple navigation comes along.

Cons: Improt.io has hard times navigating through combinations of javascript/POST and cannot navigate from one page to another (e.g. click next, second page etc).  Sometimes, it takes over 24 hours to receive the report.  Besides, it’s a browser-only app, non-compatible with other applications.

Kimono is a popular web scraper among app developers who prefer to power up their products with live data and no additional code. It saves you tons of time when you need to fill up your app with mashing data. Install Kimono Browser bookmarklet; highlight page elements you need to and provide some positive/negative examples to train the tool. After labeling all the data you can download it in CSV/JSON/a web endpoint format. The APIs created for your pages are stored in the cloud and you can run them on schedule. So far, Kimono is free to use with pro and enterprise solutions to be launched soon.

Pros: The tool works pretty fast and works great with scraping newsfeeds and prices. The data is rather accurate.

Cons: No page navigation available and you need to spend quite a lot of time to train Kimono before it starts to pull out the multi items data accurate enough. In general, I’d say Kimono is more of an app mash-ups creator than a full-scale web scraper.

 Screen Scraper  is pretty neat and tackles a lot of difficult tasks including navigation and precise data extractions, however it requires a bit of programming/tokenization skills if you’d like to run it super smooth. Launch the software, add a proxy, start recording the list of your actions and creating extracting patterns (some coding required). Works great with HTML and Javascript, however you should test it with Citrix and other platforms. Basically, screen scraper helps you writing simple web scraping scripts and lets you download the extracted data in txt/csv/excel format.

Pros: When set correctly, there’s no data extraction tasks Screen scraper fails to handle.
Cons: The tool is pricey and you’ll have to go through documentation and have basic coding skills to use it.

Source URL :  http://tech.co/4-web-scraping-tools-save-time-data-extraction-2015-03

Data Scraping - What Are Hand-Scraped Hardwood Floors and What Are the Benefits?

If you love the look of hardwood flooring with lots of character, then you may want to check out hand-scraped hardwood flooring. Hand-scraped wood provides a warm vintage look, providing the floor instant character. These types of scraped hardwoods are suitable for living rooms, dining rooms, hallways and bedrooms. But what exactly is hand-scraped hardwood flooring?

Well, it is literally what you think it is. Hand-scraped hardwood flooring is created by hand using specialized wood working tools to make each board unique and giving an overall "old worn" appearance.

At Innovation Builders we offer solid wood floors finished on site with an actual hand-scraping technique followed by stain and sealer. Solid wood floors are installed by an expert team of technicians who work each board with skilled craftsman-like attention to detail. Following the scraping procedure the floor is stained by hand with a customer selected stain color, and then protected with multiple coats of sealing and finishing polyurethane. This finishing process of staining, sealing and coating the wood floors contributes to providing the look and durability of an old reclaimed wood floor, but with today's tough, urethane finishes.

There are many, many benefits to hand-scraped wood flooring. Overall, these floors are extremely durable and hard wearing, providing years of trouble-free use. These wood floors remain looking newer for longer because the texture that the process provides hides the typical dents, dings and scratches that other floors can't hide so easily. That's great news for households with kids, dogs, and cats.

These types of wood flooring have another unique advantage as well. When you do scratch these floors during their lifetime, the scratches are easily repaired. As long as the scratch isn't too deep you can make them practically disappear without ever having to hire a professional. It's simple to hide the scratch by using a color-matched stain marker or repair kit that is readily available through local flooring distributors. These features make hand-scraped hardwood flooring a lot more durable and hassle-free to maintain than other types of wood flooring.

The expert processes utilized in the creation of these floors provides a custom look of worn wood with deep color and subtle highlights. When the light hits the wood at different times during the day, it provides an understated but powerful effect of depth and beauty. They instantly offer your rooms a rustic look full of character, allowing your home to become a warm and inviting environment. The rustic look of this wood provides a texture, style and rustic appeal that cannot be matched by any other type of flooring.

Hand-Scraped Hardwood Flooring is a floor that says welcome and adds a touch of elegance to any home. If you are looking to buy a new home and you haven't had the opportunity to see or feel hand scraped hardwoods, stop in any of the model homes at Innovation Builders in Keller, North Richland Hills or Grand Prairie, Texas and check it out!

Source URL :   http://yellowpagesdatascraping.blogspot.in/2015/06/data-scraping-what-are-hand-scraped.html