Which language is the most flexible for scraping websites?

3 down vote favorite

I'm new to programming. I know a little python and a little objective c, and I've been going through tutorials for each. Then it occurred to me, I need to know which language is more flexible (python, obj c, something else) for screen scraping a website for content.

What do I mean by "flexible"?

Well, ideally, I need something that will be easy to refactor and tweak for similar projects. I'm trying to avoid doing a lot of re-writing (well, re-coding) if I wanted to switch some of the variables in the program (i.e., the website to be scraped, the content to fetch, etc).

Anyways, if you could please give me your opinion, that would be great. Oh, and if you know any existing frameworks for the language you recommend, please share. (I know a little about Selenium and BeautifulSoup for python already).

4 Answers

I recently wrote a relatively complex web scraper to harvest a TON of data. It had to do some relatively complex parsing, I needed it to stuff it into a database, etc. I'm C# programmer now and formerly a Perl guy.

I wrote my original scraper using Python. I started on a Thursday and by Sunday morning I was harvesting over about a million scores from a show horse site. I used Python and SQLlite because they were fast.

HOWEVER, as I started putting together programs to regularly keep the data updated and to populate the SQL Server that would backend my MVC3 application, I kept hitting snags and gaps in my Python knowledge.

In the end, I completely rewrote the scraper/parser in C# using the HtmlAgilityPack and it works better than before (and just about as fast).

Because I KNEW THE LANGUAGE and the environment so much better I was able to add better database support, better logging, better error handling, etc. etc.

So... short answer.. Python was the fastest to market with a "good enough for now" solution, but the language I know best (C#) was the best long-term solution.

EDIT: I used BeautifulSoup for my original crawler written in Python.

5 down vote

The most flexible is the one that you're most familiar with.

Personally, I use Python for almost all of my utilities. For scraping, I find that its functionality specific to parsing and string manipulation requires little code, is fast and there are a ton of examples out there (strong community). Chances are that someone's already written whatever you're trying to do already, or there's at least something along the same lines that needs very little refactoring.

1 down vote

I think its safe to say that Python is a better place to start than Objective C. Honestly, just about any language meets the "flexible" requirement. All you need is well thought out configuration parameters. Also, a dynamic language like Python can go a long way in increasing flexibility, provided that you account for runtime type errors.

1 down vote

I recently wrote a very simple web-scraper; I chose Common Lisp as I'm learning the language.

On the basis of my experience - both of the language and the availability of help from experienced Lispers - I recommend investigating Common Lisp for your purpose.

There are excellent XML-parsing libraries available for CL, as well as libraries for parsing invalid HTML, which you'll need unless the sites you're parsing consist solely of valid XHTML.

Also, Common Lisp is a good language in which to implement DSLs; a DSL for web-scraping may be a solution to your requirement for flexibility & re-use.

Source: http://programmers.stackexchange.com/questions/74998/which-language-is-the-most-flexible-for-scraping-websites/75006#75006

Scraping Data: Site-specific Extractors vs. Generic Extractors

Scraping is becoming a rather mundane job with every other organization getting its feet wet with it for their own data gathering needs. There have been enough number of crawlers built – some open-sourced and others internal to organizations for in-house utilities. Although crawling might seem like a simple technique at the onset, doing this at a large-scale is the real deal. You need to have a distributed stack set up to take care of handling huge volumes of data, to provide data in a low-latency model and also to deal with fail-overs. This still is achievable after crossing the initial tech barrier and via continuous optimizations. (P.S. Not under-estimating this part because it still needs a team of Engineers monitoring the stats and scratching their heads at times).

Social Media Scraping

Focused crawls on a predefined list of sites

However, you bump into a completely new land if your goal is to generate clean and usable data sets from these crawls i.e. “extract” data in a format that your DB can process and aid in generating insights. There are 2 ways of tackling this:

a. site-specific extractors which give desired results

b. generic extractors that result in few surprises

Assuming you still do focused crawls on a predefined list of sites, let’s go over specific scenarios when you have to pick between the two-

1. Mass-scale crawls; high-level meta data – Use generic extractors when you have a large-scale crawling requirement on a continuous basis. Large-scale would mean having to crawl sites in the range of hundreds of thousands. Since the web is a jungle and no two sites share the same template, it would be impossible to write an extractor for each. However, you have to settle in with just the document-level information from such crawls like the URL, meta keywords, blog or news titles, author, date and article content which is still enough information to be happy with if your requirement is analyzing sentiment of the data.

cb1c0_one-size

A generic extractor case

Generic extractors don’t yield accurate results and often mess up the datasets deeming it unusable. Reason being

programatically distinguishing relevant data from irrelevant datasets is a challenge. For example, how would the extractor know to skip pages that have a list of blogs and only extract the ones with the complete article. Or delineating article content from the title on a blog page is not easy either.

To summarize, below is what to expect of a generic extractor.

Pros-

•    minimal manual intervention
•    low on effort and time
•    can work on any scale

Cons-

•    Data quality compromised
•    inaccurate and incomplete datasets
•    lesser details suited only for high-level analyses
•    Suited for gathering- blogs, forums, news
•    Uses- Sentiment Analysis, Brand Monitoring, Competitor Analysis, Social Media Monitoring.

2. Low/Mid scale crawls; detailed datasets – If precise extraction is the mandate, there’s no going away from site-specific extractors. But realistically this is do-able only if your scope of work is limited i.e. few hundred sites or less. Using site-specific extractors, you could extract as many number of fields from any nook or corner of the web pages. Most of the times, most pages on a website share similar templates. If not, they can still be accommodated for using site-specific extractors.

cutlery

Designing extractor for each website

Pros-

•    High data quality
•    Better data coverage on the site

Cons-

High on effort and time

Site structures keep changing from time to time and maintaining these requires a lot of monitoring and manual intervention

Only for limited scale

Suited for gathering – any data from any domain on any site be it product specifications and price details, reviews, blogs, forums, directories, ticket inventories, etc.

Uses- Data Analytics for E-commerce, Business Intelligence, Market Research, Sentiment Analysis

Conclusion

Quite obviously you need both such extractors handy to take care of various use cases. The only way generic extractors can work for detailed datasets is if everyone employs standard data formats on the web (Read our post on standard data formats here). However, given the internet penetration to the masses and the variety of things folks like to do on the web, this is being overly futuristic.

So while site-specific extractors are going to be around for quite some time, the challenge now is to tweak the generic ones to work better. At PromptCloud, we have added ML components to make them smarter and they have been working well for us so far.

What have your challenges been? Do drop in your comments.

Source: https://www.promptcloud.com/blog/scraping-data-site-specific-extractors-vs-generic-extractors/

The Features of the "Holographic Meridian Scraping Therapy"

1. Systematic nature: Brief introduction to the knowledge of viscera, meridians and points in traditional Chinese medicine, theory of holographic diagnosis and treatment; preliminary discussion of the treatment and health care mechanism of scraping therapy; systemat­ic introduction to the concrete methods of the holographic meridian scraping therapy; enumerating a host of therapeutic methods of scraping for disorders in both Chinese and Western medicine to em­body a combination of disease differentiation and syndrome differen­tiation; and summarizing the health care scraping methods. It is a practical handbook of gua sha.

2. Scientific: Applying the theories of Chinese and Western medicine to explain the health care and treatment mechanism and clinical applications of scraping therapy; introducing in detail the practical manipulations, items for attention, and indications and contraindications of the scraping therapy. Here are introduced repre­sentative diseases in different clinical departments, for which scrap­ing therapy has a better curative effect and the therapeutic methods of scraping for these diseases. Stress is placed on disease differentia­tion in Western medicine and syndrome differentiation in Chinese medicine, which should be combined in practical application.

Although there are more than 140,000 kinds of disease known to modem medicine, all diseases are related to dysfunction of the 14 meridians and internal organs, according to traditional Chinese med­icine. The object of scraping therapy is to correct the disharmony in the meridians and internal organs to recover the normal bodily func­tions. Thus, the scraping of a set of meridian points can be used to treat many diseases. In the section on clinical application only about 100 kinds of common diseases are discussed, although the actual number is much more than that. For easy reference the "Index of Diseases and Symptoms" is appended at the back of the book.

3. Practical: Using simple language and plenty of pictures and diagrams to guarantee that readers can easily leam, memorize and apply the principles of scraping therapy. As long as they master the methods explained in Chapter Three, readers without any medical knowledge can apply scraping therapy to themselves or others, with reference to the pictures in Chapters Four and Five. Besides scraping therapy, herbal treatment for each disease or syndrome is explained and may be used in combination with the scraping techniques.

Referring to the Holographic Meridian Hand Diagnosis and pic­tures at the back of the book will enhance accuracy of diagnosis and increase the effectiveness of scraping therapy.

Since the first publication and distribution of the Chinese edition of the book in July 1995, it has been welcomed by both medical specialists and lay people. In March 1996 this book was republished and adopted as a textbook by the School for Advanced Studies of Traditional Chinese Medicine affiliated to the Institute of the Acu­puncture and Moxibustion of the China Academy of Traditional Chi­nese Medicine.

In order to bring this health care method to more and more peo­ple and to make traditional Chinese medicine better appreciated They have modified and replenished this book in the spirit of constant im­provement. They hope that they may make a contribution to the health care of mankind with this natural therapy which has no side-effects and causes no pollution.

They hope that the Holographic Meridian Scraping Therapy can help the health and happiness of more and more families in the world.

Source: http://ezinearticles.com/?The-Features-of-the-Holographic-Meridian-Scraping-Therapy&id=5005031

Web Scraping Services Are Important Tools For Knowledge

Data extraction and web scraping techniques are important tools to find relevant data and information for personal or business use. Many companies, self-employed to copy and paste data from web pages. This process is very reliable, but very expensive as it is a waste of time and effort to get results. This is because the data collected and spent less resources and time required to collect these data are compared.

At present, several mining companies and their websites effective web scraping technique specifically for the thousands of pages of information developed culture can be traced. The information from a CSV file, database, XML file, or any other source with the required format is alameda. understanding of correlations and patterns in the data, so that policies can be designed to assist decision making. The information can also be stored for future reference.

The following are some common examples of data extraction process:

In order to rule through a government portal, citizens who are reliable for a given survey name removed.

Competitive pricing and data products include scraping websites

To access the web site or web design Stock download the videos and photos of scratching

Automatic Data Collection

It regularly collects data on a regular basis. Automated data collection techniques are very important because they find the company’s customer trends and market trends to help. By determining market trends, it is possible to understand customer behavior and predict the likelihood of the data will change.

The following are some examples of automated data collection:

Monitoring of special hourly rates for stocks

collects daily mortgage rates from various financial institutions

on a regular basis is necessary to check the weather

By using web scraping services, you can extract all data related to your business. Then analyzed the data to a spreadsheet or database can be downloaded and compared. Storing data in a database or in a required format and interpretation of the correlations to understand and makes it easier to identify hidden patterns.

Data extraction services, it is possible pricing, email, databases, profile data, and consistently to competitors for information about the data. Different techniques and processes designed to collect and analyze data, and has developed over time. Web Scraping for business processes that have beaten the market recently is one. It is a process from various sources such as websites and databases with large amounts of data provides.

Some of the most common methods used to scrape web crawling, text, fun, DOM analysis and include matching expression. After the process is only analyzers, HTML pages or meaning can be achieved through annotations. There are many different ways of scaling data, but more importantly is working toward the same goal. The main purpose of using web scraping service to retrieve and compile data in databases and web sites. In the business world is to remain relevant to the business process.

The central question about the relevance of web scraping contact. The process is relevant to the business world? The answer is yes. The fact that it is used by large companies in the world and many awards speaks derivatives.

Source: http://www.selfgrowth.com/articles/web-scraping-services-are-important-tools-for-knowledge

Scraping a website from a windows service

Question

Hi there.  I have a windows forms application that scrapes a website to retrieve some data.  I would like to implement the same functionality as a windows service.  The reason for this is to allow the program to run 24/7 without  having a user signed in. 

To that end, my current version of the program uses a web browser control (system.windows.forms.webbrowser) to navigate the pages, click the buttons, allow scripts to do their thing, etc.  I cannot figure out a way to do the same without the web browser control, but the web browser control cannot be instantiated in a windows service (because there is no user interface in a web service).

Does anyone have any brilliant ideas on how to get around this?

Thank you very much!

Answers

Hi Andy,

There is a tool which could let you manipulate anything you want on the website. This agile HTML parser builds a read/write DOM and supports plain XPATH or XSLT. It is a .NET code library that allows you to parse "out of the web" HTML files. The parser is very tolerant with "real world" malformed HTML. The object model is very similar to what proposes System.Xml, but for HTML documents (or streams). More information, please check:

http://htmlagilitypack.codeplex.com/

Have a nice day.

Best regards

All replies

You are not telling if you are using a .NET Express edition or not

You are not telling which Framework

You are not realy saying what data you are getting from the web site.

So

I made an example of service that work on any Studio edition (including the Express)

to install it, I supposed that you have at least the Framework2, so you will use something similar to:

    %SystemRoot%\Microsoft.NET\Framework\v2.0.50727\installutil /i C:\Test\MyWindowService\MyWindowService\bin\Release\MyWindowService.exe

In the example, I supposed that you are downloading some file from the site

You will need a reference to Windows.Form for the timer


Imports System.ServiceProcess

Imports System.Configuration.Install

Public Class WindowsService : Inherits ServiceBase

  Private Minute As Integer = 60000

  Private WithEvents Timer As New Timer With {.Interval = 30 * Minute, .Enabled = True}

  Public Sub New()

    Me.ServiceName = "MyService"

    Me.EventLog.Log = "Application"

    Me.CanHandlePowerEvent = True

    Me.CanHandleSessionChangeEvent = True

    Me.CanPauseAndContinue = True

    Me.CanShutdown = True

    Me.CanStop = True

  End Sub


  Private Sub Timer_Tick(ByVal sender As Object, ByVal e As System.EventArgs) Handles Timer.Tick

    If IO.File.Exists("C:\MyPath.Data") Then IO.File.Delete("C:\MyPath.Data")

    My.Computer.Network.DownloadFile("http://MyURL.com", "C:\MyPath.Data", "MyUserName", "MyPassword")

    'Do Something with the data downloaded

  End Sub

End Class

<Microsoft.VisualBasic.HideModuleName()> _

Module MainModule

  Public TheServiceName As String

  Public Sub main()

    Dim TheServiceApplication As New WindowsService

    TheServiceName = TheServiceApplication.ServiceName

    ServiceBase.Run(TheServiceApplication)

  End Sub

End Module

<System.ComponentModel.RunInstaller(True)> _

Public Class WindowsServiceInstaller : Inherits Installer

  Public Sub New()

    Dim serviceProcessInstaller As ServiceProcessInstaller = New ServiceProcessInstaller()

    Dim serviceInstaller As ServiceInstaller = New ServiceInstaller()

    serviceProcessInstaller.Account = ServiceAccount.LocalSystem

    serviceProcessInstaller.Username = Nothing

    serviceProcessInstaller.Password = Nothing

    serviceInstaller.DisplayName = "My Windows Service"

    serviceInstaller.StartType = ServiceStartMode.Automatic

    serviceInstaller.ServiceName = TheServiceName

    Me.Installers.Add(serviceProcessInstaller)

    Me.Installers.Add(serviceInstaller)

  End Sub

End Class



 Hello Andy,

Thanks for your post.

What do you want to scrape from the page? HttpWebRequest class ans WebClient class may be what you need. More information, please check:

The HttpWebRequest class provides support for the properties and methods defined in WebRequest and for additional properties and methods that enable the user to interact directly with servers using HTTP.

http://msdn.microsoft.com/en-us/library/system.net.httpwebrequest.aspx

The WebClient class provides common methods for sending data to or receiving data from any local, intranet, or Internet resource identified by a URI

http://msdn.microsoft.com/en-us/library/system.net.webclient.aspx

If you have any concenrs, please feel free to follow up.

Best regards



Hi Andy,

What about this problem on your side now? If you have any concerns, please feel free to follow up.

Have a nice day.

Best regards



Hi Andy,

When you come back, if you need further assistance about this issue, please feel free to let us know. We will continue to work with this issue.

Have a nice day.

Best regards



Thank you for the reply. Sorry it has taken me so long to respond.  I did not receive any notification that someone had replied!

I am using Visual Studio 2010 Ultimate Edition and the .NET framework 4.0.  Actually, I am upgrading some old code written in VB 6.0, but I can use the latest and greatest thats available.

The application uses a browser control to go to the page, fill in values, click on UI elements, read the HTML that returns, etc.  The purpose of the application is to collection useful information regularily/automatically.

I know how to create a web service, but using the web control in such a service is problematic because the web browser control was meant to be placed on a windows form.  I am not able to create a new instance of it in a project designated as a windows service.



Andy

Thank you for the reply. Sorry it has taken me so long to respond.  I did not receive any notification that someone had replied!

I thought a web request was for web services (retrieving information from them).  I am trying to retreive useful information from a website designed for interaction by a human, such as selecting items from lists and clicking buttons.   I currently use a web browser control to programmatically do what a person would do and get the pages back which in turn get parsed.

Andy



Hi Andy,

There is a tool which could let you manipulate anything you want on the website. This agile HTML parser builds a read/write DOM and supports plain XPATH or XSLT. It is a .NET code library that allows you to parse "out of the web" HTML files. The parser is very tolerant with "real world" malformed HTML. The object model is very similar to what proposes System.Xml, but for HTML documents (or streams). More information, please check:

http://htmlagilitypack.codeplex.com/

Have a nice day.

Best regards



Thanks for the suggestion.  I will go to that link and see if it will work.  I will update this post with what I find.

I am writing to check the status of the issue on your side. Would you mind letting us know the result of the suggestions? If you have any concerns, please feel free to follow up.

Have a nice day.



Best regards

Hi Liliane

Thank for the follow up reply.  I don't have an answer as of yet.  Implementing this is going to take time and I haven't been given the go-ahead by my boss to spend the time to pursue it.



Hi Andy,

Never minde. You could have a try when you feel free. If you have any further questions about this issue, please feel free to let us know. We will continue to work with you on this issue.

Have a nice day.

Best regards

Source: https://social.msdn.microsoft.com/Forums/vstudio/en-US/f5d565b1-236b-43c2-90c7-f5cc3b2c341b/scraping-a-website-from-a-windows-service

Scraping the Bottom of the Barrel - The Perils of Online Article Marketing

Many online article marketers so desperately wish to succeed, they want to dump corporate life and work for themselves out of their home. They decide they are going to create an online money making website. Therefore, they look around to see what everyone else is doing, and watch the methods others use to attract online buyers, and then they mimic their marketing, their strategies, and their business models.

Still, if you are copying what other people (less ethical people) are doing in online article marketing, those which are scraping the bottom of the barrel and using false advertising and misrepresentations, then all you are really doing is perpetuating distrust on the Internet. Therefore, you are hurting everyone, including people like me. You must realize that people like me don't appreciate that.

Let me give you a few examples of some of the things going on out there, thing that are being done by people who are ethically challenged. Far too many people write articles and then on their byline they send the Internet surfer or reader of the article to a website that has a squeeze page. The squeeze page has no real information on it, rather it asks for their name and e-mail address.

If the would-be Internet surfer is unwise enough to type in their name and email address they will be spammed by e-mail, receiving various hard-sell marketing pieces. Then, if the Internet Surfer does decide to put in their e-mail address, the website grants them access and then takes them to the page with information about what they are selling, or their online marketing "make you a millionaire" scheme.

Generally, these are five page sales letters, with tons of testimonials of people you've never heard of, and may not actually exist, and all sorts of unsubstantiated earnings claims of how much money you will make if you give them $39.35 by way of PayPal, for this limited offer "Now!" And they will send you an E-book with a strategic plan of how you can duplicate what they are doing. The reality is whatever they are doing is questionable to begin with.

If you are going to do online article marketing please don't scrape the bottom of the barrel, there's just too much competition down there from what I can see. Please consider all this.

Source: http://ezinearticles.com/?Scraping-the-Bottom-of-the-Barrel---The-Perils-of-Online-Article-Marketing&id=2710103

Hand Scraped Flooring For a Natural and Unique Look

An option in hardwood flooring that is being increasingly adopted by those looking for something new, innovative and unique for their homes is hand scraped flooring. This type of wood flooring helps one achieve a distinct natural look on one's floor and also has a couple of advantages.

There are three types of scraping that you can get done on your wooden flooring: light, medium and hard. Preferably, if you have a light colored woodwork, then you should go for light scraping and if your floor has a darker shade, then you should opt for hard scraping. But, irrespective of the type of scraping you go for, you must ensure that the laborers doing the scraping are very skilled and impeccable in their job as hand scraping floors is an art that demands patience, time, talent and hard work.

Nowadays, many people tend to go for machine scraping, attracted by the lower investment involved in it. But such people are unable to achieve the requisite natural effect on their floors as machines create patterns on the floors that are easily detectable. These patterns do not emerge with hand scraping and the consequent look is as random and unique as it gets.

Though such scraped flooring is a costly option in flooring, it demands little maintenance. While with perfectly smooth surfaces, you will be always on the edge ensuring that there are no scratches, with hand scraped floors, you will not have to be concerned about this as any new scratches will only add to the already distressed appearance of the flooring.

Prefinished hand scraped wood flooring is also available in the market nowadays. These eliminate the need of any on-site scraping. But this option is of course unsuitable for those who have already got their floors installed. As it is, if you get on-site scraping done, you will have more control over things as you would be able to see the scraping as it develops and would be therefore in a position to exercise your preferences more.

Source: http://ezinearticles.com/?Hand-Scraped-Flooring-For-a-Natural-and-Unique-Look&id=4581623