HADOOP-7531. Add servlet util methods for handling paths in requests. Contributed by Eli Collins

git-svn-id: https://svn.apache.org/repos/asf/hadoop/common/trunk@1156947 13f79535-47bb-0310-9956-ffa450edef68

hadoop-common/CHANGES.txt

@@ -322,6 +322,8 @@ Trunk (unreleased changes)
     HADOOP-7526. Add TestPath tests for URI conversion and reserved
     characters. (eli)
 
+    HADOOP-7531. Add servlet util methods for handling paths in requests. (eli)
+
   OPTIMIZATIONS
   
     HADOOP-7333. Performance improvement in PureJavaCrc32. (Eric Caspole

hadoop-common/src/main/java/org/apache/hadoop/util/ServletUtil.java

@@ -21,10 +21,15 @@ import java.io.*;
 import java.util.Calendar;
 
 import javax.servlet.*;
+import javax.servlet.http.HttpServletRequest;
 
+import org.apache.commons.httpclient.URIException;
+import org.apache.commons.httpclient.util.URIUtil;
 import org.apache.hadoop.classification.InterfaceAudience;
 import org.apache.hadoop.classification.InterfaceStability;
 
+import com.google.common.base.Preconditions;
+
 @InterfaceAudience.Private
 @InterfaceStability.Unstable
 public class ServletUtil {
@@ -107,4 +112,55 @@ public class ServletUtil {
   public static String percentageGraph(float perc, int width) throws IOException {
     return percentageGraph((int)perc, width);
   }
-}
+
+  /**
+   * Escape and encode a string regarded as within the query component of an URI.
+   * @param value the value to encode
+   * @return encoded query, null if the default charset is not supported
+   */
+  public static String encodeQueryValue(final String value) {
+    try {
+      return URIUtil.encodeWithinQuery(value, "UTF-8");
+    } catch (URIException e) {
+      throw new AssertionError("JVM does not support UTF-8"); // should never happen!
+    }
+  }
+
+  /**
+   * Escape and encode a string regarded as the path component of an URI.
+   * @param path the path component to encode
+   * @return encoded path, null if UTF-8 is not supported
+   */
+  public static String encodePath(final String path) {
+    try {
+      return URIUtil.encodePath(path, "UTF-8");
+    } catch (URIException e) {
+      throw new AssertionError("JVM does not support UTF-8"); // should never happen!
+    }
+  }
+
+  /**
+   * Parse and decode the path component from the given request.
+   * @param request Http request to parse
+   * @param servletName the name of servlet that precedes the path
+   * @return decoded path component, null if UTF-8 is not supported
+   */
+  public static String getDecodedPath(final HttpServletRequest request, String servletName) {
+    try {
+      return URIUtil.decode(getRawPath(request, servletName), "UTF-8");
+    } catch (URIException e) {
+      throw new AssertionError("JVM does not support UTF-8"); // should never happen!
+    }
+  }
+
+  /**
+   * Parse the path component from the given request and return w/o decoding.
+   * @param request Http request to parse
+   * @param servletName the name of servlet that precedes the path
+   * @return path component, null if the default charset is not supported
+   */
+  public static String getRawPath(final HttpServletRequest request, String servletName) {
+    Preconditions.checkArgument(request.getRequestURI().startsWith(servletName+"/"));
+    return request.getRequestURI().substring(servletName.length());
+  }
+}