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POmostly finished reddit crawler is failing to crawl more than 9 or so pages
 

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  1. POmostly finished reddit crawler is failing to crawl more than 9 or so pages
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    <pre><code>import java.io.FileOutputStream; import java.io.IOException; import java.io.InputStream; import java.io.OutputStream; import java.net.MalformedURLException; import java.net.URL; import java.util.Scanner; import java.util.regex.Matcher; import java.util.regex.Pattern; import org.jsoup.Jsoup; import org.jsoup.nodes.Document; import org.jsoup.nodes.Element; import org.jsoup.select.Elements; public class Scraper { private String filePath = "c://reddit//"; private String url; private int count; private String after; private static String subreddit; public Scraper(String sr) { url = String.format("http://www.reddit.com/r/%s.xml?limit=100", sr); } public static void main(String[] args) { Scanner input = new Scanner(System.in); System.out.println("enter subreddit with pics only"); subreddit = input.next(); System.out.println("enter amount of pages to crawl"); int pages = input.nextInt(); Scraper scraper = new Scraper(subreddit); input.close(); int i = 0; while (i &lt; pages) { scraper.getNextPage(); scraper.getImgur(); scraper.getImgurA(); scraper.getImgurAddI(); i++; } } public void download(String _url, String name) { /* * setup streams.. write image as bytes to filePath */ InputStream is = null; OutputStream os = null; try { URL url = new URL(_url); is = url.openStream(); os = new FileOutputStream(filePath + name + ".jpg"); for (int b; (b = is.read()) != -1;) { os.write(b); } } catch (MalformedURLException mue) { System.out.println("invalid url"); } catch (IOException e) { System.out.println("no stream"); } finally { if (is != null) { try { is.close(); } catch (IOException e) { e.printStackTrace(); } } if (os != null) { try { os.close(); } catch (IOException e) { e.printStackTrace(); } } } } public void getImgur() { /* * grab all imgur's in the context of http://i.imgur.com/. The second * parameter to download() is the filename */ try { System.out.println("connecting to imgur"); Elements description = getSubreddit(); for (Element imgur : description) { Pattern pattern = Pattern .compile("http://i\\.imgur\\.com/\\w+"); Matcher matcher = pattern.matcher(imgur.text()); if (matcher.find()) { System.out.println("downloading image: " + " " + matcher.group()); download((matcher.group() + ".jpg"), matcher.group() .substring(18)); } } } catch (Exception e) { System.out.println("getImgur() failed"); } finally { System.out.println("grabbed all imgurs"); } } public void getImgurAddI() { /* * grab all imgur's in the context of http://imgur.com/, if it is an * album then skip otherwise add "i" to beginning of imgur in order to * get image */ try { System.out.println("finding imgurs without prefix i and adding i"); Elements description = getSubreddit(); for (Element imgur : description) { Pattern pattern = Pattern.compile("http://imgur\\.com/\\w+"); Matcher matcher = pattern.matcher(imgur.text()); if (matcher.find()) { if (!matcher.group().endsWith("a")) { // make imgur downloadable by adding 'i' before imgur String newUrl = matcher.group(); newUrl = "http://i." + newUrl.substring(7); download(newUrl + ".jpg", newUrl.substring(18)); } } } } catch (Exception e) { System.out.println("getImgurAddI() failed"); } finally { System.out.println("grabbed all imgurs by adding I"); } } private void getImgurA() { /* * grab all albums then call extract() to get each individual image */ try { System.out.println("connecting to imgur album"); Elements description = getSubreddit(); for (Element imgur : description) { Pattern pattern = Pattern.compile("http://imgur.com/a/\\w+"); Matcher matcher = pattern.matcher(imgur.text()); if (matcher.find()) { System.out.println("Downloading image album...." + " " + matcher.group()); extract(matcher.group()); } } } catch (Exception e) { System.out.println("getImgurA() failed"); } finally { System.out.println("extracted all imgur albums"); } } private void extract(String album) { /* * open connection to imgur album and download each individual image, * validate imgur..if it ends with "s" most likely a thumbnail duplicate * so skip it */ try { Document doc = Jsoup.connect(album).get(); Elements pics = doc.getElementsByTag("img"); String image = null; for (Element pic : pics) { /* * get all image's inside the data-src attribute, make sure url * is valid first */ image = pic.attr("data-src"); if (image != "" &amp;&amp; (!image.substring(0, image.length() - 4).endsWith( "s"))) { if (image.endsWith(".jpg?1") || image.endsWith(".jpg?2")) { if (image.substring(2, image.length() - 6) .endsWith("s")) { System.out .println("skipping download of thumbnail/duplicate"); } else { System.out.println("extracting jpg1/jpg2..... " + image.substring(2)); download( "http://" + image.substring(2, image.length() - 2), image.substring(14, image.length() - 6)); } } else { System.out.println("extracting..... " + image.substring(2)); download("http://" + image.substring(2), image.substring(14)); } } } } catch (IOException e) { System.out.println("extract() failed"); } } public Elements getSubreddit() { /* * return an Elements with the information to be scraped * to caller method, setup user agent */ Document doc; Elements description = null; try { doc = Jsoup .connect(url) .userAgent( "Mozilla/5.0 (Windows; U; WindowsNT 5.1; en-US; rv1.8.1.6) Gecko/20070725 Firefox/2.0.0.6") .referrer("http://www.google.com").get(); description = doc.getElementsByTag("description"); } catch (IOException e) { System.out.println("getSubreddit() failed"); } return description; } public void getNextPage() { /* * crawls current url to get next url */ System.out.println("Crawling next page.............."); Document doc; try { url = url.replace(".xml", ""); doc = Jsoup.connect(url).get(); Elements next = doc.getElementsByTag("span"); for (Element n : next) { if (n.className().equals("nextprev")) { Pattern pattern = Pattern.compile("after=\\w+"); Matcher matcher = pattern.matcher(n.toString()); if (matcher.find()) { after = matcher.group().substring(6); count += 100; url = String .format("http://www.reddit.com/r/%s.xml?limit=100&amp;count=%d&amp;after=%s", subreddit, count, after); System.out.println("Crawling page.........: " + url); } } } } catch (IOException e) { System.out.println("getNextPage() failed"); } } } </code></pre> <p>Sorry this is probably hard to read I have not broken it up yet because I am still working out the kinks. It seems to crawl 9 pages without a single error than every page after that just fails, the issue is "socket timed out" or "connection timed out". Here is an example output of trying to crawl 25 pages <code>http://pastebin.com/sP9UwGk9</code>. The bigger issue is that I had it actually be a multi threaded crawler, but it failed 50x more so I made it slower. I added in bunch of Thread.sleep every time the website connected or started a download but I still kept getting errors. Is there something I am doing wrong? I know reddit has some type of limiter but I am not sure whats wrong because this program is pretty slow in the first place(unless I use the threads). </p> <p>edit: console log <a href="http://pastebin.com/fhrjSeKx" rel="nofollow">http://pastebin.com/fhrjSeKx</a></p>
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    1. PTQuestion
    1. USgallly
    1. USgallly
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    1. COWork out the kinks and then ask about a specific problem.
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      1. POmostly finished reddit crawler is failing to crawl more than 9 or so pages
      1. USSotirios Delimanolis
    2. COWhen I said kinks I meant fix the timeout issue, but I am not sure what is causing it. The error log shows that it downloads fine for a while, but towards the end every one fails.
      singulars
      1. POmostly finished reddit crawler is failing to crawl more than 9 or so pages
      1. USgallly
    3. COWhat error are you getting? What URL is it failing on?
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      1. POmostly finished reddit crawler is failing to crawl more than 9 or so pages
      1. USJeanne Boyarsky
 

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