Added preliminary code for registerPrefix.
diff --git a/ndn-cpp/face.hpp b/ndn-cpp/face.hpp
index 2b1a41a..0b7aa54 100644
--- a/ndn-cpp/face.hpp
+++ b/ndn-cpp/face.hpp
@@ -26,7 +26,7 @@
   }
   
   /**
-   * Create a new Face for communication with an NDN hub at host:port using the default UdpTransport.
+   * Create a new Face for communication with an NDN hub at host:port using the default TcpTransport.
    * @param host The host of the NDN hub.
    * @param port The port of the NDN hub.
    */
@@ -36,7 +36,7 @@
   }
   
   /**
-   * Create a new Face for communication with an NDN hub at host with the default port 9695 and using the default UdpTransport.
+   * Create a new Face for communication with an NDN hub at host with the default port 9695 and using the default TcpTransport.
    * @param host The host of the NDN hub.
    */
   Face(const char *host)
@@ -122,6 +122,29 @@
   }
   
   /**
+   * Register prefix with the connected NDN hub and call onInterest when a matching interest is received.
+   * @param prefix A reference to a Name for the prefix to register.  This copies the Name.
+   * @param onInterest A function object to call when a matching interest is received.  This copies the function object, so you may need to
+   * use func_lib::ref() as appropriate.
+   * @param flags The flags for finer control of which interests are forward to the application.
+   */
+  void registerPrefix(const Name &prefix, const OnInterest &onInterest, int flags)
+  {
+    node_.registerPrefix(prefix, onInterest, flags);
+  }
+
+  /**
+   * Register prefix with the connected NDN hub and call onInterest when a matching interest is received.
+   * @param prefix A reference to a Name for the prefix to register.  This copies the Name.
+   * @param onInterest A function object to call when a matching interest is received.  This copies the function object, so you may need to
+   * use func_lib::ref() as appropriate.
+   */
+  void registerPrefix(const Name &prefix, const OnInterest &onInterest)
+  {
+    node_.registerPrefix(prefix, onInterest);
+  }
+  
+  /**
    * Process any data to receive or call timeout callbacks.
    * This is non-blocking and will return immediately if there is no data to receive.
    * You should repeatedly call this from an event loop, with calls to sleep as needed so that the loop doesn't use 100% of the CPU.
diff --git a/ndn-cpp/node.cpp b/ndn-cpp/node.cpp
index 5bee365..1461dbf 100644
--- a/ndn-cpp/node.cpp
+++ b/ndn-cpp/node.cpp
@@ -6,7 +6,6 @@
 #include <sys/time.h>
 #include "encoding/binary-xml-decoder.hpp"
 #include "c/encoding/binary-xml.h"
-#include "data.hpp"
 #include "node.hpp"
 
 using namespace std;
@@ -21,54 +20,23 @@
   gettimeofday(&t, NULL);
   return t.tv_sec * 1000.0 + t.tv_usec / 1000.0;
 }
-  
-Node::PitEntry::PitEntry(const ptr_lib::shared_ptr<const Interest> &interest, const OnData &onData, const OnTimeout &onTimeout)
-: interest_(interest), onData_(onData), onTimeout_(onTimeout)
-{
-  // Set up timeoutTime_.
-  if (interest_->getInterestLifetimeMilliseconds() >= 0.0)
-    timeoutTimeMilliseconds_ = getNowMilliseconds() + interest_->getInterestLifetimeMilliseconds();
-  else
-    // No timeout.
-    timeoutTimeMilliseconds_ = -1.0;
-  
-  // Set up interestStruct_.
-  // TODO: Doesn't this belong in the Interest class?
-  nameComponents_.reserve(interest_->getName().getComponentCount());
-  excludeEntries_.reserve(interest_->getExclude().getEntryCount());
-  ndn_Interest_init
-    (&interestStruct_, &nameComponents_[0], nameComponents_.capacity(), &excludeEntries_[0], excludeEntries_.capacity());
-  interest_->get(interestStruct_);  
-}
 
-bool Node::PitEntry::checkTimeout(Node *parent, double nowMilliseconds)
+void Node::construct()
 {
-  if (timeoutTimeMilliseconds_ >= 0.0 && nowMilliseconds >= timeoutTimeMilliseconds_) {
-    if (onTimeout_) {
-      // Ignore all exceptions.
-      try {
-        onTimeout_(interest_);
-      }
-      catch (...) { }
-    }
-    
-    return true;
-  }
-  else
-    return false;
+  ndndIdFetcherInterest_ = Interest(Name("/%C1.M.S.localhost/%C1.M.SRV/ndnd/KEY"), 4000.0);
 }
 
 void Node::expressInterest(const Interest &interest, const OnData &onData, const OnTimeout &onTimeout)
 {
+  // TODO: Properly check if we are already connected to the expected host.
+  if (!transport_->getIsConnected())
+    transport_->connect(*connectionInfo_, *this);
+  
   shared_ptr<PitEntry> pitEntry(new PitEntry(shared_ptr<const Interest>(new Interest(interest)), onData, onTimeout));
   pit_.push_back(pitEntry);
   
   shared_ptr<vector<unsigned char> > encoding = pitEntry->getInterest()->wireEncode();  
   
-  // TODO: Properly check if we are already connected to the expected host.
-  if (!transport_->getIsConnected())
-    transport_->connect(*connectionInfo_, *this);
-  
   transport_->send(*encoding);
 }
 
@@ -84,6 +52,38 @@
     expressInterest(Interest(name, 4000.0), onData, onTimeout);
 }
 
+void Node::registerPrefix(const Name &prefix, const OnInterest &onInterest, int flags)
+{
+  if (ndndId_.size() == 0) {
+    // First fetch the ndndId of the connected hub.
+    NdndIdFetcher fetcher(make_shared<NdndIdFetcher::Info>(this, prefix, onInterest, flags));
+    // It is OK for func_lib::function make a copy of the function object because the Info is in a shared_ptr.
+    expressInterest(ndndIdFetcherInterest_, fetcher, fetcher);
+  }
+  else
+    registerPrefixHelper(prefix, onInterest, flags);
+}
+
+void Node::NdndIdFetcher::operator()(const ptr_lib::shared_ptr<const Interest> &interest, const ptr_lib::shared_ptr<Data> &ndndIdData)
+{
+  if (ndndIdData->getSignedInfo().getPublisherPublicKeyDigest().getPublisherPublicKeyDigest().size() > 0) {
+    // Set the ndndId_ and continue.
+    info_->node_.ndndId_ = ndndIdData->getSignedInfo().getPublisherPublicKeyDigest().getPublisherPublicKeyDigest();
+    info_->node_.registerPrefixHelper(info_->prefix_, info_->onInterest_, info_->flags_);
+  }
+  // TODO: else need to log not getting the ndndId.
+}
+
+void Node::NdndIdFetcher::operator()(const ptr_lib::shared_ptr<const Interest> &timedOutInterest)
+{
+  // TODO: Log the timeout.
+}
+
+void Node::registerPrefixHelper(const Name &prefix, const OnInterest &onInterest, int flags)
+{
+  throw logic_error("need to finish implementing registerPrefix");
+}
+
 void Node::processEvents()
 {
   transport_->processEvents();
@@ -146,5 +146,41 @@
     
 	return iResult;
 }
+  
+Node::PitEntry::PitEntry(const ptr_lib::shared_ptr<const Interest> &interest, const OnData &onData, const OnTimeout &onTimeout)
+: interest_(interest), onData_(onData), onTimeout_(onTimeout)
+{
+  // Set up timeoutTime_.
+  if (interest_->getInterestLifetimeMilliseconds() >= 0.0)
+    timeoutTimeMilliseconds_ = getNowMilliseconds() + interest_->getInterestLifetimeMilliseconds();
+  else
+    // No timeout.
+    timeoutTimeMilliseconds_ = -1.0;
+  
+  // Set up interestStruct_.
+  // TODO: Doesn't this belong in the Interest class?
+  nameComponents_.reserve(interest_->getName().getComponentCount());
+  excludeEntries_.reserve(interest_->getExclude().getEntryCount());
+  ndn_Interest_init
+    (&interestStruct_, &nameComponents_[0], nameComponents_.capacity(), &excludeEntries_[0], excludeEntries_.capacity());
+  interest_->get(interestStruct_);  
+}
+
+bool Node::PitEntry::checkTimeout(Node *parent, double nowMilliseconds)
+{
+  if (timeoutTimeMilliseconds_ >= 0.0 && nowMilliseconds >= timeoutTimeMilliseconds_) {
+    if (onTimeout_) {
+      // Ignore all exceptions.
+      try {
+        onTimeout_(interest_);
+      }
+      catch (...) { }
+    }
+    
+    return true;
+  }
+  else
+    return false;
+}
 
 }
diff --git a/ndn-cpp/node.hpp b/ndn-cpp/node.hpp
index 277628f..54a9a16 100644
--- a/ndn-cpp/node.hpp
+++ b/ndn-cpp/node.hpp
@@ -8,7 +8,8 @@
 
 #include "common.hpp"
 #include "interest.hpp"
-#include "transport/udp-transport.hpp"
+#include "data.hpp"
+#include "transport/tcp-transport.hpp"
 #include "encoding/binary-xml-element-reader.hpp"
 
 namespace ndn {
@@ -23,6 +24,11 @@
  */
 typedef func_lib::function<void(const ptr_lib::shared_ptr<const Interest> &)> OnTimeout;
 
+/**
+ * An OnInterest function object is used to pass a callback to registerPrefix.
+ */
+typedef func_lib::function<void(const ptr_lib::shared_ptr<const Name> &, const ptr_lib::shared_ptr<const Interest> &)> OnInterest;
+
 class Face;
   
 class Node : public ElementListener {
@@ -35,25 +41,28 @@
   Node(const ptr_lib::shared_ptr<Transport> &transport, const ptr_lib::shared_ptr<const Transport::ConnectionInfo> &connectionInfo)
   : transport_(transport), connectionInfo_(connectionInfo)
   {
+    construct();
   }
   
   /**
-   * Create a new Node for communication with an NDN hub at host:port using the default UdpTransport.
+   * Create a new Node for communication with an NDN hub at host:port using the default TcpTransport.
    * @param host The host of the NDN hub.
    * @param port The port of the NDN hub.
    */
   Node(const char *host, unsigned short port)
-  : transport_(new UdpTransport()), connectionInfo_(new UdpTransport::ConnectionInfo(host, port))
+  : transport_(new TcpTransport()), connectionInfo_(new TcpTransport::ConnectionInfo(host, port))
   {
+    construct();
   }
   
   /**
-   * Create a new Node for communication with an NDN hub at host with the default port 9695 and using the default UdpTransport.
+   * Create a new Node for communication with an NDN hub at host with the default port 9695 and using the default TcpTransport.
    * @param host The host of the NDN hub.
    */
   Node(const char *host)
-  : transport_(new UdpTransport()), connectionInfo_(new UdpTransport::ConnectionInfo(host, 9695))
+  : transport_(new TcpTransport()), connectionInfo_(new TcpTransport::ConnectionInfo(host, 9695))
   {
+    construct();
   }
 
   /**
@@ -128,6 +137,26 @@
   }
 
   /**
+   * Register prefix with the connected NDN hub and call onInterest when a matching interest is received.
+   * @param prefix A reference to a Name for the prefix to register.  This copies the Name.
+   * @param onInterest A function object to call when a matching interest is received.  This copies the function object, so you may need to
+   * use func_lib::ref() as appropriate.
+   * @param flags The flags for finer control of which interests are forward to the application.
+   */
+  void registerPrefix(const Name &prefix, const OnInterest &onInterest, int flags);
+
+  /**
+   * Register prefix with the connected NDN hub and call onInterest when a matching interest is received.
+   * @param prefix A reference to a Name for the prefix to register.  This copies the Name.
+   * @param onInterest A function object to call when a matching interest is received.  This copies the function object, so you may need to
+   * use func_lib::ref() as appropriate.
+   */
+  void registerPrefix(const Name &prefix, const OnInterest &onInterest)
+  {
+    registerPrefix(prefix, onInterest, 0);
+  }
+  
+  /**
    * Process any data to receive.  For each element received, call onReceivedElement.
    * This is non-blocking and will return immediately if there is no data to receive.
    * You should repeatedly call this from an event loop, with calls to sleep as needed so that the loop doesn't use 100% of the CPU.
@@ -194,6 +223,53 @@
   };
   
   /**
+   * An NdndIdFetcher receives the Data packet with the publisher public key digest for the connected NDN hub.
+   * This class is a function object for the callbacks. It only holds a pointer to an Info object, so it is OK to copy the pointer.
+   */
+  class NdndIdFetcher {
+  public:
+    class Info;
+    NdndIdFetcher(ptr_lib::shared_ptr<NdndIdFetcher::Info> info)
+    : info_(info)
+    {      
+    }
+    
+    /**
+     * We received the ndnd ID.
+     * @param interest
+     * @param data
+     */
+    void operator()(const ptr_lib::shared_ptr<const Interest> &interest, const ptr_lib::shared_ptr<Data> &ndndIdData);
+
+    /**
+     * We timed out fetching the ndnd ID.
+     * @param interest
+     */
+    void operator()(const ptr_lib::shared_ptr<const Interest> &timedOutInterest);
+    
+    class Info {
+    public:
+      Info(Node *node, const Name &prefix, const OnInterest &onInterest, int flags)
+      : node_(*node), prefix_(prefix), onInterest_(onInterest), flags_(flags)
+      {      
+      }
+      
+      Node &node_;
+      Name prefix_;
+      const OnInterest onInterest_;
+      int flags_;
+    };
+    
+  private:
+    ptr_lib::shared_ptr<Info> info_;
+  };
+  
+  /**
+   * Finish constructing this object.
+   */
+  void construct();
+  
+  /**
    * Find the entry from the pit_ where the name conforms to the entry's interest selectors, and
    * the entry interest name is the longest that matches name.
    * @param name The name to find the interest for (from the incoming data packet).
@@ -201,9 +277,19 @@
    */
   int getEntryIndexForExpressedInterest(const Name &name);
   
+  /**
+   * Do the work of registerPrefix once we know we are connected with an ndndId_.
+   * @param prefix
+   * @param onInterest
+   * @param flags
+   */
+  void registerPrefixHelper(const Name &prefix, const OnInterest &onInterest, int flags);
+  
   ptr_lib::shared_ptr<Transport> transport_;
   ptr_lib::shared_ptr<const Transport::ConnectionInfo> connectionInfo_;
   std::vector<ptr_lib::shared_ptr<PitEntry> > pit_;
+  Interest ndndIdFetcherInterest_;
+  std::vector<unsigned char> ndndId_;
 };
 
 }