Add MetadataObject class to encode/decode RDR-style metadata
Change-Id: I6688b630a4889614e7df5c1f91b91be370a350cd
Refs: #4707
diff --git a/AUTHORS.md b/AUTHORS.md
index 59e7e77..38fc19c 100644
--- a/AUTHORS.md
+++ b/AUTHORS.md
@@ -40,3 +40,4 @@
* Susmit Shannigrahi <https://www.linkedin.com/in/susmit-shannigrahi-90433b8>
* José Quevedo <http://atnog.av.it.pt/members/jquevedo>
* Zhiyi Zhang <http://irl.cs.ucla.edu/~zhiyi/>
+* Chavoosh Ghasemi <https://www.linkedin.com/in/chavoosh-ghasemi-421327117/>
diff --git a/ndn-cxx/metadata-object.cpp b/ndn-cxx/metadata-object.cpp
new file mode 100644
index 0000000..78ad7f4
--- /dev/null
+++ b/ndn-cxx/metadata-object.cpp
@@ -0,0 +1,97 @@
+/* -*- Mode:C++; c-file-style:"gnu"; indent-tabs-mode:nil; -*- */
+/*
+ * Copyright (c) 2013-2019 Regents of the University of California.
+ *
+ * This file is part of ndn-cxx library (NDN C++ library with eXperimental eXtensions).
+ *
+ * ndn-cxx library is free software: you can redistribute it and/or modify it under the
+ * terms of the GNU Lesser General Public License as published by the Free Software
+ * Foundation, either version 3 of the License, or (at your option) any later version.
+ *
+ * ndn-cxx library is distributed in the hope that it will be useful, but WITHOUT ANY
+ * WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A
+ * PARTICULAR PURPOSE. See the GNU Lesser General Public License for more details.
+ *
+ * You should have received copies of the GNU General Public License and GNU Lesser
+ * General Public License along with ndn-cxx, e.g., in COPYING.md file. If not, see
+ * <http://www.gnu.org/licenses/>.
+ *
+ * @author Chavoosh Ghasemi <chghasemi@cs.arizona.edu>
+ */
+
+#include "ndn-cxx/metadata-object.hpp"
+
+#include <boost/lexical_cast.hpp>
+
+namespace ndn {
+
+static_assert(std::is_base_of<tlv::Error, MetadataObject::Error>::value,
+ "MetadataObject::Error must inherit from tlv::Error");
+
+const name::Component KEYWORD_METADATA_COMP = "20 08 6D65746164617461"_block; // 32=metadata
+
+MetadataObject::MetadataObject() = default;
+
+MetadataObject::MetadataObject(const Data& data)
+{
+ if (data.getContentType() != tlv::ContentType_Blob) {
+ BOOST_THROW_EXCEPTION(Error("Expected ContentType to be BLOB but " +
+ boost::lexical_cast<std::string>(data.getContentType()) +
+ " is provided"));
+ }
+
+ if (!isValidName(data.getName())) {
+ BOOST_THROW_EXCEPTION(Error("Name " + data.getName().toUri() +
+ " is not a valid MetadataObject name"));
+ }
+
+ data.getContent().parse();
+ // ignore non-Name elements before the first one
+ m_versionedName.wireDecode(data.getContent().get(tlv::Name));
+}
+
+Data
+MetadataObject::makeData(Name discoveryInterestName,
+ KeyChain& keyChain,
+ const ndn::security::SigningInfo& si,
+ optional<uint64_t> version,
+ time::milliseconds freshnessPeriod) const
+{
+ if (discoveryInterestName.empty() || discoveryInterestName[-1] != KEYWORD_METADATA_COMP) {
+ BOOST_THROW_EXCEPTION(Error("Name " + discoveryInterestName.toUri() +
+ " is not a valid discovery Interest name"));
+ }
+ discoveryInterestName.appendVersion(version);
+ discoveryInterestName.appendSegment(0);
+
+ Data data(discoveryInterestName);
+ data.setContent(m_versionedName.wireEncode());
+ data.setFreshnessPeriod(freshnessPeriod);
+ keyChain.sign(data, si);
+
+ return data;
+}
+
+MetadataObject&
+MetadataObject::setVersionedName(const Name& name)
+{
+ m_versionedName = name;
+ return *this;
+}
+
+bool
+MetadataObject::isValidName(const Name& name)
+{
+ return name.size() >= 3 && name[-3] == KEYWORD_METADATA_COMP &&
+ name[-2].isVersion() && name[-1].isSegment();
+}
+
+Interest
+MetadataObject::makeDiscoveryInterest(Name name)
+{
+ return Interest(name.append(KEYWORD_METADATA_COMP))
+ .setCanBePrefix(true)
+ .setMustBeFresh(true);
+}
+
+} // namespace ndn
diff --git a/ndn-cxx/metadata-object.hpp b/ndn-cxx/metadata-object.hpp
new file mode 100644
index 0000000..3639b8e
--- /dev/null
+++ b/ndn-cxx/metadata-object.hpp
@@ -0,0 +1,126 @@
+/* -*- Mode:C++; c-file-style:"gnu"; indent-tabs-mode:nil; -*- */
+/*
+ * Copyright (c) 2013-2019 Regents of the University of California.
+ *
+ * This file is part of ndn-cxx library (NDN C++ library with eXperimental eXtensions).
+ *
+ * ndn-cxx library is free software: you can redistribute it and/or modify it under the
+ * terms of the GNU Lesser General Public License as published by the Free Software
+ * Foundation, either version 3 of the License, or (at your option) any later version.
+ *
+ * ndn-cxx library is distributed in the hope that it will be useful, but WITHOUT ANY
+ * WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A
+ * PARTICULAR PURPOSE. See the GNU Lesser General Public License for more details.
+ *
+ * You should have received copies of the GNU General Public License and GNU Lesser
+ * General Public License along with ndn-cxx, e.g., in COPYING.md file. If not, see
+ * <http://www.gnu.org/licenses/>.
+ *
+ * @author Chavoosh Ghasemi <chghasemi@cs.arizona.edu>
+ */
+
+#ifndef NDN_METADATA_OBJECT_HPP
+#define NDN_METADATA_OBJECT_HPP
+
+#include "ndn-cxx/data.hpp"
+#include "ndn-cxx/interest.hpp"
+#include "ndn-cxx/security/v2/key-chain.hpp"
+
+namespace ndn {
+
+/**
+ * @brief Class for RDR-style metadata encoding/decoding.
+ *
+ * The interest and data packets dealing with metadata (called "discovery interest"
+ * and "metadata", respectively) follow a specific format.
+ * @see https://redmine.named-data.net/projects/ndn-tlv/wiki/RDR
+ *
+ * Realtime Data Retrieval (RDR) is a protocol for discovering the latest version number
+ * of a given data collection. There are two names in an RDR metadata object:
+ * @li the **versioned name** is a prefix of the data collection, and generally
+ * contains a version component. It appears in the Content element of the metadata object.
+ * @li the **metadata name** is the name of the metadata object itself, and includes
+ * a keyword name component `32=metadata`, as well as version and segment components.
+ */
+class MetadataObject
+{
+public:
+ class Error : public tlv::Error
+ {
+ public:
+ using tlv::Error::Error;
+ };
+
+ /**
+ * @brief Create an empty metadata object
+ */
+ MetadataObject();
+
+ /**
+ * @brief Construct a metadata object by decoding of the given Data packet
+ * @throw tlv::Error the Data is not a valid metadata packet
+ */
+ explicit
+ MetadataObject(const Data& data);
+
+ /**
+ * @brief Create a Data packet representing this metadata object
+ *
+ * @param discoveryInterestName the discovery Interest's name, which must end with
+ * a keyword name component `32=metadata`
+ * @param keyChain KeyChain to sign the Data
+ * @param si signing parameters
+ * @param version version number of metadata packet; if nullopt, use current Unix
+ * timestamp (in milliseconds) as the version number
+ * @param freshnessPeriod freshness period of metadata packet
+ *
+ * @throw tlv::Error @p discoveryInterestName is not valid
+ */
+ Data
+ makeData(Name discoveryInterestName,
+ KeyChain& keyChain,
+ const ndn::security::SigningInfo& si = KeyChain::getDefaultSigningInfo(),
+ optional<uint64_t> version = nullopt,
+ time::milliseconds freshnessPeriod = 10_ms) const;
+
+ /**
+ * @brief Return the versioned name (i.e., the name inside the content)
+ */
+ const Name&
+ getVersionedName() const
+ {
+ return m_versionedName;
+ }
+
+ /**
+ * @brief Set the versioned name
+ *
+ * Any metadata packet carries a versioned name in its payload where it shows the name
+ * and the latest version of a data stream. For instance, `/ndn/test/%FD%97%47%1E%6C` is
+ * a versioned name that shows the latest version of `/ndn/test`.
+ */
+ MetadataObject&
+ setVersionedName(const Name& name);
+
+public: // static methods
+ /**
+ * @brief Check whether @p name can be a valid metadata name
+ */
+ static bool
+ isValidName(const Name& name);
+
+ /**
+ * @brief Generate a discovery interest packet based on @p name
+ *
+ * @param name prefix of data collection
+ */
+ static Interest
+ makeDiscoveryInterest(Name name);
+
+private:
+ Name m_versionedName;
+};
+
+} // namespace ndn
+
+#endif // NDN_METADATA_OBJECT_HPP
diff --git a/ndn-cxx/name.cpp b/ndn-cxx/name.cpp
index 4b63334..da6755f 100644
--- a/ndn-cxx/name.cpp
+++ b/ndn-cxx/name.cpp
@@ -1,6 +1,6 @@
/* -*- Mode:C++; c-file-style:"gnu"; indent-tabs-mode:nil; -*- */
/*
- * Copyright (c) 2013-2018 Regents of the University of California.
+ * Copyright (c) 2013-2019 Regents of the University of California.
*
* This file is part of ndn-cxx library (NDN C++ library with eXperimental eXtensions).
*
@@ -211,15 +211,15 @@
// ---- modifiers ----
Name&
-Name::appendVersion()
+Name::appendVersion(optional<uint64_t> version)
{
- return appendVersion(time::toUnixTimestamp(time::system_clock::now()).count());
+ return append(Component::fromVersion(version.value_or(time::toUnixTimestamp(time::system_clock::now()).count())));
}
Name&
-Name::appendTimestamp()
+Name::appendTimestamp(optional<time::system_clock::TimePoint> timestamp)
{
- return appendTimestamp(time::system_clock::now());
+ return append(Component::fromTimestamp(timestamp.value_or(time::system_clock::now())));
}
Name&
diff --git a/ndn-cxx/name.hpp b/ndn-cxx/name.hpp
index 9fa1343..ebd850c 100644
--- a/ndn-cxx/name.hpp
+++ b/ndn-cxx/name.hpp
@@ -1,6 +1,6 @@
/* -*- Mode:C++; c-file-style:"gnu"; indent-tabs-mode:nil; -*- */
/*
- * Copyright (c) 2013-2018 Regents of the University of California.
+ * Copyright (c) 2013-2019 Regents of the University of California.
*
* This file is part of ndn-cxx library (NDN C++ library with eXperimental eXtensions).
*
@@ -355,24 +355,13 @@
}
/** @brief Append a version component
+ * @param version the version number to append; if nullopt, the current UNIX time
+ * in milliseconds is used
* @return a reference to this name, to allow chaining
* @sa NDN Naming Conventions https://named-data.net/doc/tech-memos/naming-conventions.pdf
*/
Name&
- appendVersion(uint64_t version)
- {
- return append(Component::fromVersion(version));
- }
-
- /** @brief Append a version component based on current time
- *
- * The version number is the current UNIX timestamp in milliseconds
- *
- * @return a reference to this name, to allow chaining
- * @sa NDN Naming Conventions https://named-data.net/doc/tech-memos/naming-conventions.pdf
- */
- Name&
- appendVersion();
+ appendVersion(optional<uint64_t> version = nullopt);
/** @brief Append a segment number (sequential) component
* @return a reference to this name, to allow chaining
@@ -395,21 +384,12 @@
}
/** @brief Append a timestamp component
+ * @param timestamp the timestamp to append; if nullopt, the current system time is used
* @return a reference to this name, to allow chaining
* @sa NDN Naming Conventions https://named-data.net/doc/tech-memos/naming-conventions.pdf
*/
Name&
- appendTimestamp(const time::system_clock::TimePoint& timePoint)
- {
- return append(Component::fromTimestamp(timePoint));
- }
-
- /** @brief Append a timestamp component based on current time
- * @return a reference to this name, to allow chaining
- * @sa NDN Naming Conventions https://named-data.net/doc/tech-memos/naming-conventions.pdf
- */
- Name&
- appendTimestamp();
+ appendTimestamp(optional<time::system_clock::TimePoint> timestamp = nullopt);
/** @brief Append a sequence number component
* @return a reference to this name, to allow chaining
diff --git a/tests/unit/metadata-object.t.cpp b/tests/unit/metadata-object.t.cpp
new file mode 100644
index 0000000..6074c59
--- /dev/null
+++ b/tests/unit/metadata-object.t.cpp
@@ -0,0 +1,152 @@
+/* -*- Mode:C++; c-file-style:"gnu"; indent-tabs-mode:nil; -*- */
+/*
+ * Copyright (c) 2013-2019 Regents of the University of California.
+ *
+ * This file is part of ndn-cxx library (NDN C++ library with eXperimental eXtensions).
+ *
+ * ndn-cxx library is free software: you can redistribute it and/or modify it under the
+ * terms of the GNU Lesser General Public License as published by the Free Software
+ * Foundation, either version 3 of the License, or (at your option) any later version.
+ *
+ * ndn-cxx library is distributed in the hope that it will be useful, but WITHOUT ANY
+ * WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A
+ * PARTICULAR PURPOSE. See the GNU Lesser General Public License for more details.
+ *
+ * You should have received copies of the GNU General Public License and GNU Lesser
+ * General Public License along with ndn-cxx, e.g., in COPYING.md file. If not, see
+ * <http://www.gnu.org/licenses/>.
+ *
+ * @author Chavoosh Ghasemi <chghasemi@cs.arizona.edu>
+ */
+
+#include "ndn-cxx/metadata-object.hpp"
+
+#include "tests/boost-test.hpp"
+#include "tests/identity-management-fixture.hpp"
+
+namespace ndn {
+namespace tests {
+
+class MetadataObjectFixture : public IdentityManagementFixture
+{
+public:
+ MetadataObjectFixture()
+ : metadataComponent(32, reinterpret_cast<const uint8_t*>("metadata"), std::strlen("metadata"))
+ , versionedContentName(Name(baseContentName)
+ .appendVersion(342092199154ULL))
+ , metadataFullName(Name(baseContentName)
+ .append(metadataComponent)
+ .appendVersion(metadataVerNo)
+ .appendSegment(0))
+ {
+ }
+
+protected:
+ const name::Component metadataComponent;
+
+ // content prefix
+ const Name baseContentName = "/ndn/unit/tests";
+ const Name versionedContentName;
+
+ // metadata prefix
+ const uint64_t metadataVerNo = 89400192181ULL;
+ const Name metadataFullName;
+};
+
+BOOST_FIXTURE_TEST_SUITE(TestMetadataObject, MetadataObjectFixture)
+
+BOOST_AUTO_TEST_CASE(EncodeDecode)
+{
+ MetadataObject metadata1;
+ metadata1.setVersionedName(versionedContentName);
+
+ // pass metadata version number
+ const Data data1 = metadata1.makeData(metadataFullName.getPrefix(-2), m_keyChain,
+ KeyChain::getDefaultSigningInfo(), metadataVerNo);
+
+ BOOST_CHECK_EQUAL(metadata1.getVersionedName(), versionedContentName);
+ BOOST_CHECK_EQUAL(data1.getName(), metadataFullName);
+ BOOST_CHECK_EQUAL(data1.getFreshnessPeriod(), 10_ms);
+
+ // do not pass metadata version number
+ metadata1.setVersionedName(versionedContentName);
+ const Data data2 = metadata1.makeData(metadataFullName.getPrefix(-2), m_keyChain);
+ BOOST_CHECK_NE(data2.getName()[-2].toVersion(), metadataVerNo);
+
+ // construct a metadata object based on a valid metadata packet
+ MetadataObject metadata2(data1);
+
+ BOOST_CHECK_EQUAL(metadata2.getVersionedName(), versionedContentName);
+ BOOST_CHECK(baseContentName.isPrefixOf(metadata2.makeData(metadataFullName.getPrefix(-2),
+ m_keyChain).getName()));
+}
+
+BOOST_AUTO_TEST_CASE(InvalidFormat)
+{
+ Data data;
+
+ // invalid content type
+ data.setName(Name("/ndn/unit/test").append(metadataComponent));
+ data.setContentType(tlv::ContentType_Key);
+ BOOST_CHECK_THROW(MetadataObject metadata(data), tlv::Error);
+
+ // invalid metadata name
+ data.setName("/ndn/unit/test");
+ data.setContentType(tlv::ContentType_Blob);
+ BOOST_CHECK_THROW(MetadataObject metadata(data), tlv::Error);
+
+ // empty content
+ data.setName(Name("ndn/unit/test").append(metadataComponent));
+ BOOST_CHECK_THROW(MetadataObject metadata(data), tlv::Error);
+
+ // non-empty content with no name element
+ data.setContent("F000"_block);
+ BOOST_CHECK_THROW(MetadataObject metadata(data), tlv::Error);
+}
+
+BOOST_AUTO_TEST_CASE(IsValidName)
+{
+ // valid name
+ Name name = Name("/ndn/unit/test")
+ .append(metadataComponent)
+ .appendVersion()
+ .appendSegment(0);
+ BOOST_CHECK(MetadataObject::isValidName(name));
+
+ // invalid names
+ // segment component is missing
+ BOOST_CHECK_EQUAL(MetadataObject::isValidName(name.getPrefix(-1)), false);
+
+ // version component is missing
+ BOOST_CHECK_EQUAL(MetadataObject::isValidName(name.getPrefix(-2)), false);
+
+ // keyword name component `32=keyword` is missing
+ BOOST_CHECK_EQUAL(MetadataObject::isValidName(name.getPrefix(-3)), false);
+
+ // too short name
+ BOOST_CHECK_EQUAL(MetadataObject::isValidName(name.getPrefix(-4)), false);
+
+ // out-of-order segment and version components
+ name = name.getPrefix(-2).appendSegment(0).appendVersion();
+ BOOST_CHECK_EQUAL(MetadataObject::isValidName(name), false);
+
+ // invalid name component keyword
+ name = name.getPrefix(-3)
+ .append(32, reinterpret_cast<const uint8_t*>("foo"), std::strlen("foo"))
+ .appendVersion()
+ .appendSegment(0);
+ BOOST_CHECK_EQUAL(MetadataObject::isValidName(name), false);
+}
+
+BOOST_AUTO_TEST_CASE(MakeDiscoveryInterest)
+{
+ Interest interest = MetadataObject::makeDiscoveryInterest(baseContentName);
+ BOOST_CHECK_EQUAL(interest.getName(), Name(baseContentName).append(metadataComponent));
+ BOOST_CHECK(interest.getCanBePrefix());
+ BOOST_CHECK(interest.getMustBeFresh());
+}
+
+BOOST_AUTO_TEST_SUITE_END() // TestMetadataObject
+
+} // namespace tests
+} // namespace ndn