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Diffstat (limited to 'app/src/main/java/de/danoeh/antennapod/ui/cleaner/HtmlToPlainText.java')
-rw-r--r-- | app/src/main/java/de/danoeh/antennapod/ui/cleaner/HtmlToPlainText.java | 123 |
1 files changed, 123 insertions, 0 deletions
diff --git a/app/src/main/java/de/danoeh/antennapod/ui/cleaner/HtmlToPlainText.java b/app/src/main/java/de/danoeh/antennapod/ui/cleaner/HtmlToPlainText.java new file mode 100644 index 000000000..29099c1fd --- /dev/null +++ b/app/src/main/java/de/danoeh/antennapod/ui/cleaner/HtmlToPlainText.java @@ -0,0 +1,123 @@ +package de.danoeh.antennapod.ui.cleaner; + +import android.text.TextUtils; + +import org.apache.commons.lang3.StringUtils; +import org.jsoup.Jsoup; +import org.jsoup.internal.StringUtil; +import org.jsoup.nodes.Document; +import org.jsoup.nodes.Element; +import org.jsoup.nodes.Node; +import org.jsoup.nodes.TextNode; +import org.jsoup.select.NodeTraversor; +import org.jsoup.select.NodeVisitor; + +import java.util.regex.Pattern; + +/** + * This class is based on <code>HtmlToPlainText</code> from jsoup's examples package. + * + * HTML to plain-text. This example program demonstrates the use of jsoup to convert HTML input to lightly-formatted + * plain-text. That is divergent from the general goal of jsoup's .text() methods, which is to get clean data from a + * scrape. + * <p> + * Note that this is a fairly simplistic formatter -- for real world use you'll want to embrace and extend. + * </p> + * <p> + * To invoke from the command line, assuming you've downloaded the jsoup jar to your current directory:</p> + * <p><code>java -cp jsoup.jar org.jsoup.examples.HtmlToPlainText url [selector]</code></p> + * where <i>url</i> is the URL to fetch, and <i>selector</i> is an optional CSS selector. + * + * @author Jonathan Hedley, jonathan@hedley.net + * @author AntennaPod open source community + */ +public class HtmlToPlainText { + + /** + * Use this method to strip off HTML encoding from given text. + * Replaces bullet points with *, ignores colors/bold/... + * + * @param str String with any encoding + * @return Human readable text with minimal HTML formatting + */ + public static String getPlainText(String str) { + if (!TextUtils.isEmpty(str) && isHtml(str)) { + HtmlToPlainText formatter = new HtmlToPlainText(); + Document feedDescription = Jsoup.parse(str); + str = StringUtils.trim(formatter.getPlainText(feedDescription)); + } else if (TextUtils.isEmpty(str)) { + str = ""; + } + + return str; + } + + /** + * Use this method to determine if a given text has any HTML tag + * + * @param str String to be tested for presence of HTML content + * @return <b>True</b> if text contains any HTML tags<br /><b>False</b> is no HTML tag is found + */ + private static boolean isHtml(String str) { + final String htmlTagPattern = "<(\"[^\"]*\"|'[^']*'|[^'\">])*>"; + return Pattern.compile(htmlTagPattern).matcher(str).find(); + } + + /** + * Format an Element to plain-text + * @param element the root element to format + * @return formatted text + */ + public String getPlainText(Element element) { + FormattingVisitor formatter = new FormattingVisitor(); + // walk the DOM, and call .head() and .tail() for each node + NodeTraversor.traverse(formatter, element); + + return formatter.toString(); + } + + // the formatting rules, implemented in a breadth-first DOM traverse + private static class FormattingVisitor implements NodeVisitor { + + private final StringBuilder accum = new StringBuilder(); // holds the accumulated text + + // hit when the node is first seen + public void head(Node node, int depth) { + String name = node.nodeName(); + if (node instanceof TextNode) { + append(((TextNode) node).text()); // TextNodes carry all user-readable text in the DOM. + } else if (name.equals("li")) { + append("\n * "); + } else if (name.equals("dt")) { + append(" "); + } else if (StringUtil.in(name, "p", "h1", "h2", "h3", "h4", "h5", "tr")) { + append("\n"); + } + } + + // hit when all of the node's children (if any) have been visited + public void tail(Node node, int depth) { + String name = node.nodeName(); + if (StringUtil.in(name, "br", "dd", "dt", "p", "h1", "h2", "h3", "h4", "h5")) { + append("\n"); + } else if (name.equals("a")) { + append(String.format(" <%s>", node.absUrl("href"))); + } + } + + // appends text to the string builder with a simple word wrap method + private void append(String text) { + if (text.equals(" ") && + (accum.length() == 0 || StringUtil.in(accum.substring(accum.length() - 1), " ", "\n"))) { + return; // don't accumulate long runs of empty spaces + } + + accum.append(text); + } + + @Override + public String toString() { + return accum.toString(); + } + } +} |