Merge pull request #2138 from mfietz/2126-atom-html

Sanitize HTML from Atom feed descriptions/subtitles

1 files changed, 89 insertions, 0 deletions

diff --git a/core/src/main/java/de/danoeh/antennapod/core/util/syndication/HtmlToPlainText.java b/core/src/main/java/de/danoeh/antennapod/core/util/syndication/HtmlToPlainText.java
new file mode 100644
index 000000000..bd40f398d
--- /dev/null
+++ b/core/src/main/java/de/danoeh/antennapod/core/util/syndication/HtmlToPlainText.java
@@ -0,0 +1,89 @@
+package de.danoeh.antennapod.core.util.syndication;
+
+import org.jsoup.helper.StringUtil;
+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;
+
+/**
+ * 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 {
+
+    /**
+     * 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();
+        NodeTraversor traversor = new NodeTraversor(formatter);
+        traversor.traverse(element); // walk the DOM, and call .head() and .tail() for each node
+
+        return formatter.toString();
+    }
+
+    // the formatting rules, implemented in a breadth-first DOM traverse
+    private class FormattingVisitor implements NodeVisitor {
+
+        private 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();
+        }
+    }
+}