14 ms·

I Don’t Need No Stinking API: Web Scraping For Fun and Profit

• bdcravens 14y ago
  Another issue not covered: file downloads. Let's say you have a process that creates a dynamic image, or logs in and downloads dynamic PDFs. Even Selenium can't handle this (the download dialog is an OS-level feature). At one point I was able to get Chrome to auto-download in Selenium, but had zero control over filename and where it was saving. I ended up using iMacros (the pay version) to drive this (using Windows instances: their Linux version is very immature comparably).
  • dphase 14y ago
    I've done this successfully with Ruby Mechanize.
    • bdcravens 14y ago
      Awesome. I'd love some hints or links, as I'm always looking to refactor.
      • goostavos 14y ago
        In general, if you're going the mechanize route, .retrieve() is the function your looking for. e.g. br = mechanize.Browser() br.retrieve("https://www.google.com/images/srpr/logo3w.png, google_logo.png)[0] Mechanize doesn't really have a proper doc, but just about everything you'd need could be figured out from the very lengthy examples page on their site.
        • bdcravens 14y ago
          Playing with it now, and while it seems to hit my download need, I can't seem to get it to play nice with sites that are JavaScript dependent. Am I missing something, or is there a way to plugin an underlying WebKit engine?
          • bryogenic 14y ago
            PhantomJS is capable of downloading binary content from js dependent sites but it is a journey to get it working as it is not an out-of-the-box feature. Instead use CasperJS to drive Phantom and get a ton of snazzy features including simple binary downloads. Happy scraping!
• thisisnotatest 14y ago
  Craigslist, anyone?
  • marcamillion 14y ago
    I actually wrote a CL crawler in Ruby - https://github.com/marcamillion/craigslist-ruby-crawler https://github.com/marcamillion/craigslist-ruby-crawler I used it to crawl for freelance web dev gigs, but it can be re-purposed to do anything.
  • nishantbamb 14y ago
    Try http://www.leadscracker.com http://www.leadscracker.com
• joe_the_user 14y ago
  An important topic. The main caveat is that this may violate a site's terms of use and thus website owners may feel called upon to sue you. Depending on circumstances, the legal situation here can be a long story.
  • frabcus 14y ago
    Yes, it is complicated. That said, this is partly just because there aren't enough cases - and partly because the law hasn't stabilised (took a century to stabilise after invention of printing press). It isn't clear what rights society should grant yet, for maximising business. My take on it, from ScraperWiki's point of view: http://blog.scraperwiki.com/2012/04/02/is-scraping-legal/ http://blog.scraperwiki.com/2012/04/02/is-scraping-legal/
• mmastrac 14y ago
  I'm surprised that no one has attempted to write a Twitter client based solely on scraping to get around the token limits.
  • splatzone 14y ago
    Or an alternative API that uses the scraped data from Twitter to make requests... but that might be getting a bit ambitious (and legally dodgy)
    • jQueryIsAwesome 14y ago
      Create an script that scraps proxies and then use those to scrap twitter, use it in a Russian domain, claim 140 characters can't be copyrighted, claim that the tweets are being extracted from third party sites that use the twitter API but lack any kind of TOS and disclaimer; sell API access, profit!
  • level09 14y ago
    Perhaps they were afraid of legal issues ? scraping for fun is okay, but if you would like to build a business most people would prefer to abide by the terms of use and still use the API. remember the story of Pad Mapper ?
  • RBerenguel 14y ago
    I've written some in-browser JS to download all my tweets without needing to resort to the API and oAuth nightmare. It is indeed possible to write a client, but not recommended at all...
    • delgermurun 14y ago
      how did you send cross domain request?
  • thefreeman 14y ago
    if they really needed that much data they probably just requested access to the full phirehose
• toyg 14y ago
  And this is why we can't have nice things. Web scraping, as fun as it is (and btw, this title again abuses "Fun and Profit"), is not a practice we should encourage. Yes, it's the sort of dirty practice many people do, at one point or another, but it shouldn't be glorified.
  • baddox 14y ago
    Why? I would gladly encourage web scraping.
    • jswanson 14y ago
      Totally agree, scraping is great. I can see site operators being against the practice though, as it (usually): - generates no ad revenue - often enables someone else to use data that you struggled to put together, allowing others to profit with no gain for you - hit's edge cases that were never optimized for (as it does not follow real user access)
      • rizzom5000 14y ago
        Right, and this is why sites like Craigslist explicitly forbid scraping. If the site operators wanted, explicitly, to share their data with you, they would provide an API or give you permission to scrape. The reality of scraping was really known many years ago. If you're doing if for above-board reasons like for research etc., you'll probably get a pass - if you're doing it in order to profit from someone else's work because you are too lazy to do it yourself, it's probably unethical and you won't get a pass --- these concepts have been around for at least a thousand years or more. Full Disclosure: I have also scraped data - but only from government websites where the scraped data is explicitly public domain to begin with and APIs were not available.
        • freshhawk 14y ago
          1. That doesn't address search engines, which are doing it to profit from someone else's work. If you open the door for search engines then how many search engine like things do you give passes to? 2. What if I'm scraping it just for me, because I want a different interface? How many friends can I share that with? Can I open source the program? 3. What if I read a bunch of these sites to do research and write up a story on something about it? Not plagiarizing, just summarizing and providing analysis on craigslist rental prices? What if I do this every day? What if I automate that process? The data is transformed just as much as if I had read it myself and crunched the numbers myself, I made just as many requests to the site as my browser would have. Concepts that have been around a thousand years or more are not fully applicable. Like the printing press, some things alter the scarcity equation for ideas and data distribution and ownership. Considering how little we've agreed on about print after 500 years I have some doubts that this is as closed an issue as you say.
• kevinpfab 14y ago
  The issue with web scraping is that it relies on the scraper to keep up with changes made to the site. If a site owner changes the layout or implements a new feature, the programs depending on the scraper immediately fail. This is much less likely to happen when working with official APIs.
  • latchkey 14y ago
    In most cases, the site doesn't have an api... so we scrape and take the risk that the structure will change. One thing that helps is using tools which give you jquery-like selectors because they give a lot of freedom and are very easy to write/update.
    • lazyfunctor 14y ago
      I agree, CSS selectors in BeautifulSoup and pyquery make it less messy.
  • prezjordan 14y ago
    This should be stressed - sites like Facebook do exactly this. Constant changes mean constantly updating your scraper. When it comes to A/B testing? Your scraper needs to intelligent find the data, which might not always be in the same place. Sidenote: I wonder if any webapps use randomly generated IDs and class names (linked in the CSS) to prevent scraping. I guess this would be a caching nightmare, though.
    • freshhawk 14y ago
      I bet you would only need to randomly shuffle between a few alternatives for all of them. You'd need a dedicated effort to work that one out and the cache implications could be managed. No getting around the trade-off of possible page alternatives vs cache nightmare-ness though, and doing that to json apis would get ugly fast. At least it's easier to code these tricks than to patch a scraper to get around them.
    • level09 14y ago
      Yes, Facebook used to do that. I had to scrap it once and was surprised by randomly changing classes around input fields. but who cares, no one can beat Xpath :)
• mbustamante 14y ago
  when i need to scrap a webpage, i use phpQuery (http://code.google.com/p/phpquery/ http://code.google.com/p/phpquery/), it's dead simple if you have experience with jQuery and i get all the benefits of a server-side programming language.
  • zevyoura 14y ago
    A similar module for node.js: https://github.com/mape/node-scraper https://github.com/mape/node-scraper
    • latchkey 14y ago
      Better than that is http://node.io/ http://node.io/ Also, don't use jsdom (it is slow and strict), https://github.com/MatthewMueller/cheerio https://github.com/MatthewMueller/cheerio is much better.
  • lazyjones 14y ago
    For Perl you can use Web::Query (but don't use the default HTML::TreeBuilder::XPath with it, it's extremely slow - use http://search.cpan.org/dist/HTML-TreeBuilder-LibXML/ http://search.cpan.org/dist/HTML-TreeBuilder-LibXML/), or Mojo::DOM (part of Mojolicious: http://mojolicio.us/ http://mojolicio.us/). Both use the nowdays standard CSS selectors for comfortable handling. JavaScript can be scraped using WWW::Mechanize::Plugin::JavaScript or even WWW::Mechanize::Firefox).
• cynwoody 14y ago
  Great read! In the past, I have successfully used HtmlUnit to fulfill my admittedly limited scraping needs. It runs headless, but it has a virtual head designed to pretend it's a user visting a web application to be be tested for QA purposes. You just program it to go through the motions of a human visting a site to be tested (or scraped). E.g., click here, get some response. For each whatever in the response, click and aggregate the results in your output (to whatever granularity). Alas, it's in Java. But, if you use JRuby, you can avoid most of the nastiness that implies. (You do need to know Java, but at least you don't have to write Java.) Hartley, what is your recommended toolkit? I note you mentioned the problem of dynamically generated content. You develop your plan of attack using the browser plus Chrome Inspector or Firebug. So far, so good. But what if you want to be headless? Then you need something that will generate a DOM as if presenting a real user interface but instead simply returns a reference to the DOM tree that you are free to scan and react to.
  • bdcravens 14y ago
    Headless: Xvfb on Linux. (Virtual Framebuffer, let's you run apps that require a GUI) You can use one of the many options that include Webkit (like phantom.js, the capybara-webkit gem, or Selenium if you want a real browser like Firefox to do the work)
    • iamjustlooking 14y ago
      PhantomJS doesn't need Xvfb anymore it can run headless without this dependency.
      • catch23 14y ago
        well, it wasn't due to anything in phantomjs actually -- it was because qt introduced project lighthouse & their qt platform abstraction. project lighthouse was a fork that got integrated into qt 4.8 that phantomjs includes. (you can see the entire qt source tree if you git-clone phantomjs)
• treelovinhippie 14y ago
  Not every site. There is data I would really love to access on Facebook without having to gain specific authorization from the user. It's odd that for most user profiles the most you can extract via the graph API (with no access token) is their name and sex. Whereas I can visit their profile page in the browser, see all sorts of info and latest updates (and not even be friends with them) Tried scraping Facebook. They have IP blocks and the like.
  • RBerenguel 14y ago
    Do it in JS, client-side with 3 second delays. I have used this to get available data (location, name, status, etc) from the latest 500 available likes of a page I manage
• bdcravens 14y ago
  I've done a ton of scraping (mostly legal: on behalf of end users of an app on sites they have legit access to). This article misses something that affects several sites: JavaScript driven content. Faking headers and even setting cookies doesn't get around this. This is of course is easy to get around, using something like phantom.js or Selenium. Selenium is great because unlike all the whiz bang scraping techniques, you're driving a real browser and your requests look real (if you make 10000 requests to index.php and never pull down a single image, you might look a bit suspicious). There's a bit more overhead, but micro instances on EC2 can easily run 2 or 3 Selenium sessions at the same time, and at 0.3 cents per hour for spot instances, you can have 200-300 browsers going for 30-50 cents/hour.
  • joering2 14y ago
    +1. Thanks for the hints about Selenium. My 2c about scraping - when you try to obtain data from large websites, always go for javascript content. Pages like Newegg or Amazon * may change html outline very often even without a single alteration to the front-user and even your smartest regex can have a brain fart. In contrast, even when site gets major overhaul, most likely old javascript will be left in place with all up to date variables, because engineers will be concerned of removing that code not to break some functionality . * given you have rights to scrap. not that there are no tools to debug the site; but I found websites like mentioned plus youtube, and bunch others just not fiddling too much with js.
    • codewright 14y ago
      > even your smartest regex can have a brain fart If you're using regex to solve this sort of problem, your code deserves to break, I'm sorry.
      • bdcravens 14y ago
        I've found that regex is very brittle when you don't control what comes across. DOM traversal is far more reliable.
• RaSoJo 14y ago
  I love HTML scraping. But Javascript???...The juiciest data sets these days are increasingly in JS. For the love of me i can't get around scraping JS :( I do know that Selenium can be used for this...but am yet to see a decent example for the same. Does anyone have any good resources/examples on JS scraping that they could share?? I would be eternally grateful.
  • bdcravens 14y ago
    See my other comment :-) I've been doing this on a site that is 100% Javascript-driven for over a year, very successfully. It's really no different than hitting a static site with Selenium. Figuring out the proper XPath to use is often the biggest challenge: Chrome Developer tools help immensely. Also, you need to watch for delays in JS rendering, so put a lot of pauses in your scripts. It's of course slow, so if you want to distribute it across several machines, use Selenium Grid or a queue system (SQS, Resque, etc). Setup Xvfb to run on headless Linux instances.
  • level09 14y ago
    That is actually very simple, and you can even use a headless browser to execute javascript: first install Xvfb and pyvirtualdisplay then try this snippet https://gist.github.com/4243582 https://gist.github.com/4243582 selenium is great, it can even wait for ajax requests to finish (see WebDriverWait) ..
    • RaSoJo 14y ago
      Yippie...that worked. Thanks a ton for sharing that code snippet. Am unfortunately more of an analyst. Have only just started picking up coding for data analysis. JS scraping was one area that I always had difficulty with. Not anymore :D
    • kanzure 14y ago
      > first install Xvfb and pyvirtualdisplay You really don't need xvfb anymore. Use xserver-xorg-video-dummy.
  • freshhawk 14y ago
• derrida 14y ago
  (shameless plug) I can scrape asynchronously, anonymously, with JS wizardry, and feed it into your defined models in your MVC (e.g. Django). But! I need to get to a hacker conference on the other side of the world (29c3). Any other time of year, I'd just drop a tutorial. See profile if you'd like to help me with a consulting gig. EDIT: Knowledge isn't zero-sum. Here's an overview of a kick-ass way to spider/scrape: I use Scrapy to spider asynchronously. When I define the crawler bot as an object, if the site contains complicated stuff (stateful forms or javascript) I usually create methods that involve importing either Mechanize or QtWebKit. Xpath selectors are also useful for the ability to not have to specify the entire XML tree from trunk to leaf. I then import pre-existing Django models from a site I want the data to go into and write to the DB. At this point you usually have to convert some types. I find Scrapy cleaner and more like a pipeline so it seems to produce less 'side effect kludge' than other scraping methods (if anybody has seen a complex Beautiful Soup + Mechanize scraper you know what I mean by 'side effect kludge'). It can also act as a server to return json. Being asynchronous, you can do crazy req/s. I will leave out how to do all this through Tor because I don't want the Tor network being abused but am happy to talk about it one on one if your interest is beyond spamming the web. Through this + a couple of unmentioned tricks, it's possible to get insane data, so much so it crosses over into security research & could be used for pen-testing.
• jbranchaud 14y ago
  The title makes it sound as if there is going to be some discussion of how the OP has made web scraping profitable, but this seems to have been left to the reader's imagination. Otherwise, great article! I agree that BeautifulSoup is a great tool for this.
• deleted 14y ago
  [deleted]
• opminion 14y ago
  How about publicly available web scraping tools as a way to encourage sites to provide good APIs? Everybody wants efficiency, after all.
• kuhn 14y ago
  This is a shameless plug but I've created a service that aims to help with a lot of the issues that OP describes such as rate limiting, JS and scaling. It's a bit like Heroku for web scraping and automation. It's still in beta but if anyone is interested then check out http://tubes.io http://tubes.io.
• senthilnayagam 14y ago
  I have done a bit of scrapping with ruby mechanize, when we hit limits have circumvented by proxy and tor google as a search engine crawls most all sites, but offers very few usable stuff to other bots http://www.google.com/robots.txt http://www.google.com/robots.txt Disallow 247 Allow 41
• 6ren 14y ago
  This illustrates the significant difference between the use-cases of "web APIs" and conventional APIs, that the former are more like a database CRUD (including REST), rather than a request for computation. They (usually) are an alternative interface to a website (a GUI), and that's how most websites are used. e.g. an API for HN would allow story/comment retrieval, voting, submission, commenting. They could be used for computation, but (mostly) aren't.
• yayitswei 14y ago
  I've found diffbot to be quite useful for scraping.
• aleprok 14y ago
  There is just one major trouble with not needing stinking API. You can not POST as a possible client without requiring them to give their password to you, which actually would give you full access to their account instead of limited access with API.
  • Dylan16807 14y ago
    You seem to be talking about a specific site? Which one?
    • aleprok 14y ago
      Any social network where you can post messages for the user in the users message stream.
• alhenaadams 14y ago
  To all HN: All this being said, how do we prevent our sites from being scraped in this way? What can you not get around, and what are the potential uses for an 'unscrapeable' site to your mind.
  • zalew 14y ago
    if you don't want something to be scrapped, don't publish it on the internet. scrapping prevention reminds me of blocking right-click and other ridiculous solutions back in the day. hey, if I can view it, it means the data reached my end point.
• im3w1l 14y ago
  People seem to wonder how to handle ajax. The answer is HttpFox. It records all http-requests. 1. Start recording 2. Do some action that causes data to be fetched 3. Stop recording. You will find the url, the returned data, and a nice table of get and post-variables. https://addons.mozilla.org/en-us/firefox/addon/httpfox/ https://addons.mozilla.org/en-us/firefox/addon/httpfox/
  • mylittlepony 14y ago
    Isn't this the same as what the Net tab from Firebug does?
    • hartleybrody 14y ago
      Yah, I don't understand why people make things so complicated once Javascript gets involved. Just inspect the XHR traffic to your browser ("Network" tab in Web Inspector, Firebug, etc) as you update the information on the page. You'll quickly discover what are essentially undocumented APIs returning the data used to generate the page. You don't need to use or even read through the Javascript that's calling them, you just need to figure out what parameters and cookies are being sent, and tweak those as you wish. You might have to spoof the Referer header so that it thinks the request is still coming from their website.
  • kanzure 14y ago
    > The answer is HttpFox. It records all http-requests. http://mitmproxy.org/ http://mitmproxy.org/
  • thomasrambaud 14y ago
    Firebug is a lot better.
• clark-kent 14y ago
  The problem with scraping instead of using the API is that when the website makes even a slight change to their markup it breaks your code. I have had that experience and it's a living hell. I can say it's not worth it to scrap when there is an API available.
• thenomad 14y ago
  I had to do some scraping of a rather Javascript-heavy site last year - I found the entire process was made almost trivial using Ruby and Nokugiri. Particularly relevant for a non-uber-programmer like me, it's simple to use, as well as powerful.
• pknerd 14y ago
  If it's not automated and a fewer times, I will prefer IMacro to perform tasks on my behalf. The best part of it that you can integrate a Db to record your desired data.
• eranation 14y ago
  relevant: http://www.codinghorror.com/blog/2009/02/rate-limiting-and-velocity-checking.html http://www.codinghorror.com/blog/2009/02/rate-limiting-and-v...
• shocks 14y ago
  Node.js is excellent for web scaping, especially if you're scraping large amounts very often.
  • chadscira 14y ago
    I made this module for this exact reason: https://github.com/icodeforlove/node-requester https://github.com/icodeforlove/node-requester. Supports horrible things like proxy rotation.
    • kanzure 14y ago
      > Supports horrible things like proxy rotation. Do you have any plans to track which proxies are actually working, or how quickly each one is blocked? I want a reverse proxy on my outgoing requests that knows how to shift my traffic around properly so that I don't get banned. I don't want to be rate limited and I don't want to sit here for weeks trying to figure out wtf the rate limit is in the first place.
      • chadscira 14y ago
        interesting, im sure you can build this into it. you could hook onto the didRequestFail method and flag IPs (log this.proxy out to see what the proxy was). all i would need to do is add a method that makes it easier to add/remove proxies.
    • shocks 14y ago
      This looks great. I think I will incorporate this into some of my projects.
• SG- 14y ago
  When scraping HTML where data gets populated with js/ajax, you can get a web inspector to look at where that data is coming from and manually GET it and it will likely be in some nice JSON. Scraping used to be the way to get data back in the days, but websites also didn't change their layout/structure on a weekly basis too back then and were much more static when it came to the structure. Having recently written a small app that was forced to scrape HTML and having to update it every month to make it keep working, I can't imagine doing this for a larger project and maintaining it.
• buster 14y ago
  I so not agree with that article, it makes me sick. And this guy basically is some "marketer" so no wonder he gets quite some stuff wrong, imo. :p
  • namidark 14y ago
    What did he get wrong?
• kaffeinecoma 14y ago
  From the article: Since the third party service conducted rate-limiting based on IP address (stated in their docs), my solution was to put the code that hit their service into some client-side Javascript, and then send the results back to my server from each of the clients. This way, the requests would appear to come from thousands of different places, since each client would presumably have their own unique IP address, and none of them would individually be going over the rate limit. Pretty sure the browser Same Original Policy forbids this. Think about it- if this worked, you'd be able to scrape inside corporate firewalls simply by having users visit your website from behind the firewall.
  • kanzure 14y ago
    > Since the third party service conducted rate-limiting based on IP By the way, that's one of my projects. You can use a basic fibonacci-related algorithm to figure out (in the most minimal number of requests) what exactly the rate limit is. This way, you can scrape at just under the maximum limit. I am still working on this core library though. :|
    • hartleybrody 14y ago
      Sounds pretty interesting! Be sure to share it when it's ready.
  • hartleybrody 14y ago
    That's a great point, for most web services, this request would be blocked at the browser level by the Same Origin Policy. Fortunately for me, this site allowed client-side calls by returning a Access-Control-Allow-Origin: * header[1], specifically designed to allow this type of cross-domain access. [1]: http://en.wikipedia.org/wiki/Same_origin_policy#Cross-Origin_Resource_Sharing http://en.wikipedia.org/wiki/Same_origin_policy#Cross-Origin...
• jmgunn87 14y ago
  So bloody true. A web page is a resource just like an xml doc, there's no reason public facing urls and web content can't be treated as such and I regularly take advantage of that fact aswell. great post
• zarino 14y ago
  Related: If you fancy writing scrapers for fun and profit, ScraperWiki (a Liverpool, UK-based data startup) is currently hiring full-time data scientists. Check us out! http://scraperwiki.com/jobs/#swjob5 http://scraperwiki.com/jobs/#swjob5
  • hartleybrody 14y ago
    very well played :)
• ComputerGuru 14y ago
  What is it with all the headlines this week abusing the classic "for fun and profit" title?
• lazyjones 14y ago
  Scraping could be made a lot harder by website publishers, but they all depend on the biggest scraper accessing their content so it can bring traffic: Google ... The biggest downside of scraping is that it often takes a long time for very little content (e.g. scraping online stores with extremely bloated HTML and 10-25 products/per page).
  • JoeAltmaier 14y ago
    As a pioneer of scraping (NetProphet, the first interactive stock charting app with push-data) we initially scraped every quote we had in our database from other sites. The fundamental problem is, web pages can change a lot. We constantly had scraper scripts fail either because the web pages changed for some innocuous reason, or they noticed the scraping and blocked us. We resorted to a list of scrape targets and constantly-updating scrape-scripts to adapt continuously to the 'market'. We also pinged each target to find the least congested. Eventually we got our own stock feed (guy that did that is a research scientist at Adobe now) and stopped scraping altogether. But it was a wild ride.
    • lazyjones 14y ago
      We still need to scrape many (several 100) clients' websites because they are unable to give us product feeds (adequate ones or any at all) for their stores. But hey, it gives us a small edge because we try harder than the competition.
• bconway 14y ago
  No Rate-Limiting Clearly someone's never spent time diagnosing the fun that is scaping HN (yes, unofficial API is available).
• tectonic 14y ago
  Checkout http://selectorgadget.com http://selectorgadget.com as a useful tool for coming up with CSS selectors.
• reledi 14y ago
  Automated web testing tools, such as Watir and Selenium, are also pretty good options. I'm especially surprised Watir hasn't been mentioned yet in the comments.
  • stackthatcode 14y ago
    Indeed - or WatiN, the .NET port of WatiR. I've done some pretty heavy duty scraping and automation with WatiN, which included building a OO framework that trivialized writing scripts. Good stuff.
• SiVal 14y ago
  What I wish I could do is capture Flash audio (or any audio) streams with my Mac. All I want is to listen to the audio-only content with an audio player when I'm out driving or jogging, etc. Audio-only content that has to be played off a web page usually runs into the contradiction that if I'm in a position to click buttons on my web browser (not driving, for example), I'm in a position to do my REAL work and have no time to listen to the audio. I'll go to the web page, see whatever ads they may have, but then I'd like to be able to "scrape" the audio stream into a file so I don't have to sit there staring at a static web page the whole time I'm listening.
  • codewright 14y ago
    I used to work at a company where capturing flash video and audio streams was a regular part of our work. You're not going to like the answer. You basically have to proxy everything through a proxy that can be given a command or otherwise instructed to capture the top 3 or 4 streams from the website. From there you can either dumbly accept the largest one or start checking byte headers.
  • wslh 14y ago
    My company has an API to do that but it works on Windows: http://www.nektra.com/products/deviare-api-hook-windows/ http://www.nektra.com/products/deviare-api-hook-windows/
  • voltagex_ 14y ago
    Wireshark & RTMPDump may get you most of the way there.
• rsingel 14y ago
  There are some recent federal cases (Weev http://www.wired.com/opinion/2012/11/att-ipad-hacker-when-embarassment-becomes-a-crime/ http://www.wired.com/opinion/2012/11/att-ipad-hacker-when-em..., Aaron Swartzhttp://www.wired.com/threatlevel/2012/09/aaron-swartz-felony/ http://www.wired.com/threatlevel/2012/09/aaron-swartz-felony..., and a prosecution of scalpers http://www.wired.com/threatlevel/2010/07/ticketmaster/ http://www.wired.com/threatlevel/2010/07/ticketmaster/) that view scraping as a felony hacking offense. The feds think that an attempt to evade CAPTCHAS, IP and MAC blocks is a felony worthy of years in prison. In fact, the feds might think that clearing your cookies or switching browsers to get another 10 free articles from the NYTimes is also felony hacking. Which is to say, be careful what you admit to in this forum AND how you characterize what you are doing in your private conversations and e-mails. Weev now faces a decade or more in prison because he drummed up publicity by sending emails to journalists that used the verb "stole".
  • hartleybrody 14y ago
    Very good point, I've added the following disclaimer: While scraping can sometimes be used as a legitimate way to access all kinds of data on the internet, it’s also important to consider the legal implications. As was pointed out in the comments on HN[1], there are many cases where scraping data may be considered illegal, or open you to the possibility of being sued. Similar to using a firearm, some uses of web scraping techniques can be used for utility or sport, while others can land you in jail. I am not a lawyer, but you should be smart about how you use it. [1]: Linking to this (parent) comment
    • rsingel 14y ago
      Thanks for adding that and linking. The feds are nutter butter these days.
• mcgwiz 14y ago
  It's pointless to think of it as "wrong" for third-parties to web-scrape. Entities will do as they must to survive. The onus of mitigating web scraping, if in the interests of the publisher, is on the publisher. As a startup developer, third-party scraping is something I need to be aware of, that I need to defend against if doing so suits my interests. A little bit of research shows that this is not impractical. Dynamic IP restrictions (or slowbanning), rudimentary data watermarking, caching of anonymous request output all mitigate this. Spot-checking popular content by running it through Google Search requires all of five minutes per week. At that point, the specific situation can be addressed holistically (a simple attribution license might make everyone happy). With enough research, one might consider hellbanning the offender (serving bogus content to requests satisfying some certain heuristic) as a deterrent. A legal pursuit with its cost would likely be a last resort. Accept the possibility of being scraped and prepare accordingly.
• thomasrambaud 14y ago
  I think the author just completly missed the point with API vs Screen scraping. The API allows for accessing structured data. Even if the website changes once, the datas would be accessible the same way through the API. Whereas, the author, would have to rewrite his code each time an update his made to the front-office code of the website. A simple API providing simple json response with http basic auth is far more efficient than a screen scraping program where you have to parse the response using HTML / XML parsers.
  • frabcus 14y ago
    This isn't always the case - APIs often change. Facebook, for example, is (at least was, a few years ago) notoriously bad at changing in an unpredictable and buggy way, and I stopped using it for that reason. Some HTML scrapers are more reliable than that. As for efficiency, again not such an issue. HTML is very good these days, compared to 10 years ago, a simple CSS selector often does the job.
    • thomasrambaud 14y ago
      This is true, but APIs are often versionned. Concerning efficiency this is true CSS / XPath processors, at least, both offer very nice performances. But download 70KB of HTML each time you only need a single data, where the API request cost only a few (avg < 2KB), can be such a pain if you need to do this frequently. This can be handled by a scalable configuration but I find it a bit the overkill.
• kragen 14y ago
  Be careful. I got banned from Google for scraping. I did a few hundred thousand searches one day, and that night, they banned my office IP address for a week. This was in 2001, so I estimate I cost them a few hundred dollars, which is now impossible to repay. :(
• metalruler 14y ago
  From a site owner's perspective: if you have a LOT of data then scraping can be very disruptive. I've had someone scraping my site for literally months, using hundreds of different open proxies, plus multiple faked user-agents, in order to defeat scraping detection. At one point they were accessing my site over 300,000 times per day (3.5/sec), which exceeded the level of the next busiest (and welcome) agent... Googlebot. In total I estimate this person has made more than 30 million fetch attempts over the past few months. I eventually figured out a unique signature for their bot and blocked 95%+ of their attempts, but they still kept trying. I managed to find a contact for their network administrator and the constant door-knocking finally stopped today.