Onion Monero Blockchain Explorer

Curently available Monero blockchain explorer websites have several limitations which are of special importance to privacy-oriented users:

• they use JavaScript,
• have images which might be used for cookieless tracking,
• track users activates through google analytics,
• are closed sourced,
• are not available as hidden services,
• provide only basic search capabilities,
• can't identify users outputs based on provided Monero address and viewkey.

In this example, these limitations are addressed by development of an Onion Monero Blockchain Explorer. The example not only shows how to use Monero C++ libraries, but also demonstrates how to use:

• crow - C++ micro web framework
• lmdb++ - C++ wrapper for the LMDB
• mstch - C++ {{mustache}} templates
• rapidjson - C++ JSON parser/generator

Address

Tor users:

• http://xmrblocksvckbwvx.onion

Non tor users, can use its clearnet version (thanks to Gingeropolous):

• http://explore.MoneroWorld.com

Onion Monero Blockchain Explorer features

The key features of the Onion Monero Blockchain Explorer are

• available as a hidden service,
• no javascript, no cookies, no web analytics trackers, no images,
• open sourced,
• made fully in C++,
• the only explorer showing encrypted payments ID,
• the only explorer with the ability to search by encrypted payments ID, tx public keys, stealth addresses, input key images, output amount index and its amount,
• the only explorer showing ring signatures,
• the only explorer showing transaction extra field,
• the only explorer showing public components of Monero addresses,
• the only explorer that can show which outputs belong to the given Monero address and viewkey,
• the only explorer showing detailed information about mixins, such as, mixins' age, timescale, mixin of mixins,
• the only explorer showing number of amount output indices.

Prerequisite

Everything here was done and tested using Monero 0.9.4 on Ubuntu 16.04 x86_64.

Instruction for Monero 0.9 compilation and Monero headers and libraries setup are as shown here:

• Compile Monero 0.9 on Ubuntu 16.04 x64
• lmdbcpp-monero

C++ code

int main(int ac, const char* av[]) {

    // get command line options
    xmreg::CmdLineOptions opts {ac, av};

    auto help_opt = opts.get_option<bool>("help");

    // if help was chosen, display help text and finish
    if (*help_opt)
    {
        return EXIT_SUCCESS;
    }

    auto port_opt           = opts.get_option<string>("port");
    auto bc_path_opt        = opts.get_option<string>("bc-path");
    auto custom_db_path_opt = opts.get_option<string>("custom-db-path");
    auto deamon_url_opt     = opts.get_option<string>("deamon-url");

    //cast port number in string to uint16
    uint16_t app_port = boost::lexical_cast<uint16_t>(*port_opt);

    // get blockchain path
    path blockchain_path;

    if (!xmreg::get_blockchain_path(bc_path_opt, blockchain_path))
    {
        cerr << "Error getting blockchain path." << endl;
        return EXIT_FAILURE;
    }

     // enable basic monero log output
    xmreg::enable_monero_log();

    // create instance of our MicroCore
    // and make pointer to the Blockchain
    xmreg::MicroCore mcore;
    cryptonote::Blockchain* core_storage;

    // initialize mcore and core_storage
    if (!xmreg::init_blockchain(blockchain_path.string(),
                               mcore, core_storage))
    {
        cerr << "Error accessing blockchain." << endl;
        return EXIT_FAILURE;
    }

    // create instance of page class which
    // contains logic for the website
    xmreg::page xmrblocks(&mcore, core_storage, *deamon_url_opt);

    // crow instance
    crow::SimpleApp app;

    CROW_ROUTE(app, "/")
    ([&]() {
        return xmrblocks.index2();
    });

    CROW_ROUTE(app, "/page/<uint>")
    ([&](size_t page_no) {
        return xmrblocks.index2(page_no);
    });

    CROW_ROUTE(app, "/block/<uint>")
    ([&](size_t block_height) {
        return xmrblocks.show_block(block_height);
    });

    CROW_ROUTE(app, "/block/<string>")
    ([&](string block_hash) {
        return xmrblocks.show_block(block_hash);
    });

    CROW_ROUTE(app, "/tx/<string>")
    ([&](string tx_hash) {
        return xmrblocks.show_tx(tx_hash);
    });

    CROW_ROUTE(app, "/tx/<string>/<uint>")
    ([&](string tx_hash, uint with_ring_signatures) {
        return xmrblocks.show_tx(tx_hash, with_ring_signatures);
    });

    CROW_ROUTE(app, "/myoutputs").methods("GET"_method)
    ([&](const crow::request& req) {

        string tx_hash     = string(req.url_params.get("tx_hash"));
        string xmr_address = string(req.url_params.get("xmr_address"));
        string viewkey     = string(req.url_params.get("viewkey"));

        return xmrblocks.show_my_outputs(tx_hash, xmr_address, viewkey);
    });

    CROW_ROUTE(app, "/search").methods("GET"_method)
    ([&](const crow::request& req) {
        return xmrblocks.search(string(req.url_params.get("value")));
    });

    CROW_ROUTE(app, "/autorefresh")
    ([&]() {
        uint64_t page_no {0};
        bool refresh_page {true};
        return xmrblocks.index2(page_no, refresh_page);
    });

    // run the crow http server
    app.port(app_port).multithreaded().run();

    return EXIT_SUCCESS;
}

Example screenshot

Compile and run the explorer

Monero headers and libraries setup

The Onion Explorer uses Monero C++ libraries and headers. Also some functionality in the Explorer for mempool is achieved through patching the Monero deamon. Instructions how to download Monero source files, apply a patch, compile Monero, setup header and library files are presented here:

• https://github.com/moneroexamples/compile-monero-09-on-ubuntu-16-04 (Ubuntu 16.04)
• https://github.com/moneroexamples/compile-monero-09-on-arch-linux (Arch Linux)

Custom lmdb database (optional)

Most unique search abilities of the Onion Explorer are achieved through using a custom lmdb database constructed based on the Monero blockchain. The reason for the custom database is that Monero's own lmdb database has limited search abilities. For example, its not possible to search for a tx having a given key image, except by performing an exhaustive search on the blockchain which is very time consuming.

Instruction how to compile the lmdbcpp-monero are provided here:

• https://github.com/moneroexamples/lmdbcpp-monero.git

The custom database is rather big, 12GB now, and it must be running alongside Monero deamon so that it keeps updating itself with new information from new blocks as they are added to the blockchain.

For these reasons, its use is optional. However, without it, some searches wont be possible, e.g., searching for key images, output and tx public keys, encrypted payments id.

Compile and run the explorer

Once the Monero is compiled and setup, the explorer can be downloaded and compiled as follows:

# download the source code
git clone https://github.com/moneroexamples/onion-monero-blockchain-explorer.git

# enter the downloaded sourced code folder
cd onion-monero-blockchain-explorer

# create the makefile
cmake .

# compile
make

When compilation finishes executable xmrblocks should be created.

To run it:

./xmrblocks

Example output:

[mwo@arch onion-monero-blockchain-explorer]$ ./xmrblocks
2016-May-28 10:04:49.160280 Blockchain initialized. last block: 1056761, d0.h0.m12.s47 time ago, current difficulty: 1517857750
(2016-05-28 02:04:49) [INFO    ] Crow/0.1 server is running, local port 8081

Go to your browser: http://127.0.0.1:8081

Other examples

Other examples can be found on github. Please know that some of the examples/repositories are not finished and may not work as intended.

How can you help?

Constructive criticism, code and website edits are always good. They can be made through github.

Some Monero are also welcome:

48daf1rG3hE1Txapcsxh6WXNe9MLNKtu7W7tKTivtSoVLHErYzvdcpea2nSTgGkz66RFP4GKVAsTV14v6G3oddBTHfxP6tU