Building DCore

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Installing prerequisites in Linux

For Debian 10/Ubuntu 18.04 LTS or later, execute in console:

sudo apt-get install apt-transport-https curl gnupg lsb-release software-properties-common
curl https://bintray.com/user/downloadSubjectPublicKey?username=decentfoundation | sudo apt-key add -
sudo add-apt-repository "deb [arch=amd64] https://dl.bintray.com/decentfoundation/$(lsb_release -is | tr "[:upper:]" "[:lower:]") $(lsb_release -cs) libpbc"
sudo apt-get install build-essential make cmake g++ doxygen git libreadline-dev libcrypto++-dev libgmp-dev libpbc-dev libssl-dev libcurl4-openssl-dev libboost-all-dev zlib1g-dev
mkdir ~/dev

# Download and build JSON 3.7.3
curl -LO https://github.com/nlohmann/json/archive/v3.7.3.tar.gz
tar xf v3.7.3.tar.gz
cd json-3.7.3
cmake .
sudo make -j$(nproc) install
cd ..
rm -rf json-3.7.3 v3.7.3.tar.gz

Note for Debian 9/Ubuntu 16.04 LTS legacy systems, the default versions of Boost and CMake installed are too old and not supported. In order to install a supported ones, in addition to the common commands above, execute the following in console (in the same shell session, where you are going to build DCore itself):

# Download and build Boost 1.65.1
 curl -LO https://sourceforge.net/projects/boost/files/boost/1.65.1/boost_1_65_1.tar.gz
 tar xf boost_1_65_1.tar.gz
 mkdir boost
 cd boost_1_65_1
 export BOOST_ROOT=$(realpath ../boost)
 ./bootstrap.sh --prefix=$BOOST_ROOT
 ./b2 -j$(nproc) install
 cd ..
 rm -rf boost_1_65_1 boost_1_65_1.tar.gz

# Download and build CMake 3.13.4
 curl -LO https://cmake.org/files/v3.13/cmake-3.13.4.tar.gz
 tar xf cmake-3.13.4.tar.gz
 mkdir cmake
 cd cmake-3.13.4
 export CMAKE_ROOT=$(realpath ../cmake)
 ./configure --prefix=$CMAKE_ROOT
 make -j$(nproc) install
 export PATH=$CMAKE_ROOT/bin:$PATH
 cd ..
 rm -rf cmake-3.13.4 cmake-3.13.4.tar.gz

For Fedora 30 or later, execute in console:

sudo dnf install curl
sudo curl https://bintray.com/user/downloadSubjectPublicKey?username=decentfoundation -o /etc/pki/rpm-gpg/RPM-GPG-KEY-decentfoundation
sudo curl https://docs.decent.ch/assets/bintray-decentfoundation-fedora.repo -o /etc/yum.repos.d/bintray-decentfoundation.repo
sudo dnf install make cmake gcc-c++ doxygen git readline-devel cryptopp-devel openssl-devel gmp-devel libpbc-devel libcurl-devel json-devel zlib-devel boost-devel boost-static
mkdir ~/dev

For CentOS 8, execute in console:

sudo dnf install curl
sudo curl https://bintray.com/user/downloadSubjectPublicKey?username=decentfoundation -o /etc/pki/rpm-gpg/RPM-GPG-KEY-decentfoundation
sudo curl https://docs.decent.ch/assets/bintray-decentfoundation-centos.repo -o /etc/yum.repos.d/bintray-decentfoundation.repo
sudo dnf install https://dl.fedoraproject.org/pub/epel/epel-release-latest-8.noarch.rpm
sudo dnf install --enablerepo PowerTools make cmake gcc-c++ doxygen git readline-devel cryptopp-devel openssl-devel gmp-devel libpbc-devel libcurl-devel json-devel zlib-devel boost-devel boost-static
mkdir ~/dev

Installing prerequisites in MacOS

• Install Xcode and Command Line Tools as described in http://railsapps.github.io/xcode-command-line-tools.html
• Install Homebrew, see http://brew.sh

Then, execute in console:

$ brew install cmake boost cryptopp openssl@1.1 pbc nlohmann-json readline doxygen git ipfs
$ brew link --force readline
$ mkdir ~/dev

Installing prerequisites in Windows

• Install Git for Windows (https://gitforwindows.org)
• Install CMake tools (https://cmake.org/download)
• Install Visual Studio 2017 Community (https://visualstudio.microsoft.com/downloads)
• Install Doxygen (http://www.doxygen.org) (choose C:\Doxygen as installation prefix)
• Install Perl (http://strawberryperl.com) (choose C:\Strawberry as installation prefix)

Then, start Visual Studio 2017 x64 Native Tools Command Prompt and execute:

mkdir \Projects
cd \Projects
git clone https://github.com/Microsoft/vcpkg.git
cd vcpkg
bootstrap-vcpkg.bat
vcpkg --triplet x64-windows-static install cryptopp curl openssl pbc nlohmann-json

Obtaining the sources

After all the prerequisites are installed, execute in console (change current path to ~/dev in Linux/MacOS or to \Projects in Windows):

git clone https://github.com/DECENTfoundation/DECENT-Network.git
cd DECENT-Network
git submodule update --init --recursive

Building and installing DCore in Linux or MacOS

In order to build and install DCore, execute in console:

mkdir -p ~/dev/DECENT-Network-build
cd ~/dev/DECENT-Network-build
cmake -G "Unix Makefiles" -DCMAKE_BUILD_TYPE=Release ~/dev/DECENT-Network
cmake --build . --target all -- -j -l 3.0
cmake --build . --target install

Note that, in case of "Unix Makefiles" CMake generator, the last two commands are equivalent to:

$ make -j -l 3.0 install

DCore artifacts are installed at /usr/local directory by default. You can specify any other custom install prefix for cmake during the initial configuration, for example, by adding -DCMAKE_INSTALL_PREFIX=~/dev/DECENT-Network-prefix to the command line.

You can use any path instead of ~/dev in the steps above.

You can use Xcode, or any other CMake generator, and then, if it is an IDE generator, instead of building and installing via cmake in terminal, open the generated project/solution file in the corresponding IDE and perform ALL_BUILD and INSTALL (or install) actions from there.

Building and installing DCore in Windows

In order to build and install DCore follow the steps:

• start Visual Studio 2017, navigate to File > Open > Folder and choose C:\Projects\DECENT-Network
• navigate to CMake > Change CMake Settings > DCore and adjust installation prefix and paths to Doxygen, Perl and vcpkg (if needed)
• build and install artifacts using CMake > Install > DCore

You can use CMake generator to create a Visual Studio 2017 project files and perform Build > Build solution action from there, just start the Visual Studio 2017 x64 Native Tools Command Prompt and execute:

cd \Projects\DECENT-Network
cmake -DCMAKE_TOOLCHAIN_FILE=C:\Projects\vcpkg\scripts\buildsystems\vcpkg.cmake -DVCPKG_TARGET_TRIPLET=x64-windows-static -DCMAKE_BUILD_TYPE=Release -DCMAKE_PREFIX_PATH=C:\Doxygen;C:\Strawberry\perl -G "Visual Studio 15 2017 Win64" .

You can specify any other custom install prefix for cmake during the initial configuration, for example, by adding -DCMAKE_INSTALL_PREFIX=C:\Projects\DECENT-Network-prefix to the command line.

You can use any path instead of C:\Projects in the steps above.

Building DCore in Docker

You can also build Docker image which will run as DCore network node. Image will be based on either Ubuntu, Debian, Fedora or CentOS Linux, for the details go to Docker repository.

Starting DCore

In the commands below, change /usr/local to ~/dev/DECENT-Network-prefix or to any other install location, that you specified during initial configuration.

On first run decentd will create .decent in the home directory, if doesn't exist already.

$ /usr/local/bin/decentd

Optionally, now press Ctrl-C to stop decentd. You can edit configuration in ~/.decent/data/decentd/config.ini.

Then, run the DCore daemon again:

$ /usr/local/bin/decentd

This will launch the DCore daemon node with the default genesis.

Then, in a separate console, start the command-line wallet by executing:

$ cd ~/dev/DECENT-Network-working-dir
$ /usr/local/bin/cli_wallet

To set your initial password to mypassword, execute:

>>> set_password mypassword
>>> unlock mypassword

To import your account keys, execute:

>>> import_key [name] [private_wif_key]

DCore daemon

The role of the DCore daemon is to broadcast transactions, download blocks, and optionally sign them.

$ /usr/local/bin/decentd --rpc-endpoint 127.0.0.1:8090 --enable-stale-production -w 1.4.0

Testing DCore

Seeder plugin is responsible for automatically announce seeder's capablity, downloading content, seeding it and distributing keys. In order to enable it follow these steps:

1. Generarate El-Gamal keys using cli_wallet command (first one is private, second one is public)

    generate_el_gamal_keys
   

2. Add parameters to the DCore daemon

    --seeder [account-id] --seeder-private-key [private_wif_key] --content-private-key [el_gamal_private_key] --packages-path [path] --seeding-price [price] --free-space [free-space]
   

   where [account-id] is one of your accounts, [private_wif_key] corresponding active key, [el_gamal_private_key] is the generated El-Gamal key, [path] is a filesystem location with at least [space] Megabytes available, and [price] is publishing price per MB per day, in satoshis.

Using the API

We provide several different API's. Each API has its own ID. When running decentd, initially two API's are available: API 0 provides read-only access to the database, while API 1 is used to login and gain access to additional, restricted API's.

Here is an example using wscat package from npm for websockets:

$ npm install -g wscat
$ wscat -c ws://127.0.0.1:8090
> {"id":1, "method":"call", "params":[0,"get_accounts",[["1.2.0"]]]}
< {"id":1,"result":[{"id":"1.2.0","annotations":[],"membership_expiration_date":"1969-12-31T23:59:59","registrar":"1.2.0","referrer":"1.2.0","lifetime_referrer":"1.2.0","network_fee_percentage":2000,"lifetime_referrer_fee_percentage":8000,"referrer_rewards_percentage":0,"name":"committee-account","owner":{"weight_threshold":1,"account_auths":[],"key_auths":[],"address_auths":[]},"active":{"weight_threshold":6,"account_auths":[["1.2.5",1],["1.2.6",1],["1.2.7",1],["1.2.8",1],["1.2.9",1],["1.2.10",1],["1.2.11",1],["1.2.12",1],["1.2.13",1],["1.2.14",1]],"key_auths":[],"address_auths":[]},"options":{"memo_key":"GPH1111111111111111111111111111111114T1Anm","voting_account":"1.2.0","num_miner":0,"num_committee":0,"votes":[],"extensions":[]},"statistics":"2.7.0","whitelisting_accounts":[],"blacklisting_accounts":[]}]}

We can do the same thing using an HTTP client such as curl for API's which do not require login or other session state:

$ curl --data '{"jsonrpc": "2.0", "method": "call", "params": [0, "get_accounts", [["1.2.0"]]], "id": 1}' http://127.0.0.1:8090/rpc
{"id":1,"result":[{"id":"1.2.0","annotations":[],"membership_expiration_date":"1969-12-31T23:59:59","registrar":"1.2.0","referrer":"1.2.0","lifetime_referrer":"1.2.0","network_fee_percentage":2000,"lifetime_referrer_fee_percentage":8000,"referrer_rewards_percentage":0,"name":"committee-account","owner":{"weight_threshold":1,"account_auths":[],"key_auths":[],"address_auths":[]},"active":{"weight_threshold":6,"account_auths":[["1.2.5",1],["1.2.6",1],["1.2.7",1],["1.2.8",1],["1.2.9",1],["1.2.10",1],["1.2.11",1],["1.2.12",1],["1.2.13",1],["1.2.14",1]],"key_auths":[],"address_auths":[]},"options":{"memo_key":"GPH1111111111111111111111111111111114T1Anm","voting_account":"1.2.0","num_miner":0,"num_committee":0,"votes":[],"extensions":[]},"statistics":"2.7.0","whitelisting_accounts":[],"blacklisting_accounts":[]}]}

API 0 is accessible using regular JSON-RPC:

$ curl --data '{"jsonrpc": "2.0", "method": "get_accounts", "params": [["1.2.0"]], "id": 1}' http://127.0.0.1:8090/rpc

Accessing restricted API's

You can restrict API's to particular users by specifying an api-access file in config.ini. Here is an example apiaccess file which allows user decent with password pwd to access four different API's, while allowing any other user to access the three public API's necessary to use the wallet:

{
   "permission_map" :
   [
      [
         "decent",
         {
            "password_hash_b64" : "W/wGhp3F9QOPwyCCpAPSQTrRnoQJi7IrI98ttwCJwCE=",
            "password_salt_b64" : "8Bd7FkJHI/8=",
            "allowed_apis" : ["database_api", "network_broadcast_api", "history_api", "network_node_api"]
         }
      ],
      [
         "*",
         {
            "password_hash_b64" : "*",
            "password_salt_b64" : "*",
            "allowed_apis" : ["database_api", "network_broadcast_api", "history_api"]
         }
      ]
   ]
}

Passwords are stored in base64 as salted sha256 hashes. A simple Python script, saltpass.py is avaliable to obtain hash and salt values from a password. A single asterisk "*" may be specified as username or password hash to accept any value.

With the above configuration, here is an example of how to call add_node from the network_node API:

{"id":1, "method":"call", "params":[1,"login",["bytemaster", "supersecret"]]}
{"id":2, "method":"call", "params":[1,"network_node",[]]}
{"id":3, "method":"call", "params":[2,"add_node",["127.0.0.1:9090"]]}

Note, the call to network_node is necessary to obtain the correct API identifier for the network API. It is not guaranteed that the network API identifier will always be 2.

Questions

• Is there a way to generate help with parameter names and method descriptions?

  Yes. Documentation of the code base, including APIs, can be generated using Doxygen. Simply run doxygen in this directory.

  If both Doxygen and perl are available in your build environment, the CLI wallet's help and gethelp commands will display help generated from the doxygen documentation.

  If your CLI wallet's help command displays descriptions without parameter names like signed_transaction transfer(string, string, string, string, string, bool) it means CMake was unable to find Doxygen or perl during configuration. If found, the output should look like this: signed_transaction transfer(string from, string to, string amount, string asset_symbol, string memo, bool broadcast)

• Is there a way to allow external program to drive cli_wallet via websocket, JSONRPC, or HTTP?

  Yes. External programs may connect to the CLI wallet and make its calls over a websockets API. To do this, run the wallet in server mode, i.e. cli_wallet -s "127.0.0.1:9999" and then have the external program connect to it over the specified port (in this example, port 9999).

• Is there a way to access methods which require login over HTTP?

  No. Login is inherently a stateful process (logging in changes what the server will do for certain requests, that's kind of the point of having it). If you need to track state across HTTP RPC calls, you must maintain a session across multiple connections. This is a famous source of security vulnerabilities for HTTP applications. Additionally, HTTP is not really designed for "server push" notifications, and we would have to figure out a way to queue notifications for a polling client.

  Websockets solves all these problems. If you need to access DCore's stateful methods, you need to use Websockets.

• What is the meaning of a.b.c numbers?

  The first number specifies the space. Space 1 is for protocol objects, 2 is for implementation objects. Protocol space objects can appear on the wire, for example in the binary form of transactions. Implementation space objects cannot appear on the wire and solely exist for implementation purposes, such as optimization or internal bookkeeping.

  The second number specifies the type. The type of the object determines what fields it has. For a complete list of type ID's, see enum local_object_type, enum protocol_object_type and enum impl_object_type in types.hpp.

  The third number specifies the instance. The instance of the object is different for each individual object.

• The answer to the previous question was really confusing. Can you make it clearer?

  All account ID's are of the form 1.2.x. If you were the 9735th account to be registered, your account's ID will be 1.2.9735. Account 0 is special (it's the "committee account," which is controlled by the committee members and has a few abilities and restrictions other accounts do not).

  All asset ID's are of the form 1.3.x. If you were the 29th asset to be registered, your asset's ID will be 1.3.29. Asset 0 is special (it's DCT, which is considered the "core asset").

  The first and second number together identify the kind of thing you're talking about (1.2 for accounts, 1.3 for assets). The third number identifies the particular thing.

• How do I get the network_add_nodes command to work? Why is it so complicated?

  You need to follow the instructions in the "Accessing restricted API's" section to allow a username/password access to the network_node API. Then you need to pass the username/password to the cli_wallet on the command line or in a config file.

  It's set up this way so that the default configuration is secure even if the RPC port is publicly accessible. It's fine if your decentd allows the general public to query the database or broadcast transactions (in fact, this is how the hosted web UI works). It's less fine if your decent allows the general public to control which p2p nodes it's connecting to. Therefore the API to add p2p connections needs to be set up with proper access controls.