Onion Monero Blockchain Explorer

Currently available Monero blockchain explorers 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,
• do not support Monero testnet,
• have limited JSON API.

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
• mstch - C++ {{mustache}} templates
• json - JSON for Modern C++
• fmt - Small, safe and fast string formatting library

Addresses

Tor users:

• http://dvwae436pd7nt4bc.onion

Clearnet versions:

• http://139.162.32.245:8081/ - bleeding edge version, no https.
• https://xmrchain.net/ - https enabled, most popular and very stable.
• https://monerohash.com/explorer/ - nice looking one, https enabled.
• http://explore.MoneroWorld.com - same as the second one.
• https://explorer.xmr.my/ - nice looking one, https enabled.
• https://explorer.monero-otc.com/ - https enabled.
• http://monerochain.com/ - JSON API based, multiple nodes.
• http://66.85.74.134:8081/ - fluffynet subnet explorer.

Clearnet testnet Monero version:

• http://139.162.32.245:8082/ - bleeding edge version, no https.
• https://testnet.xmrchain.com/ - https enabled.

i2p users (main Monero network) - down for now:

• http://monerotools.i2p

Alternative block explorers:

• http://moneroblocks.info
• https://monerobase.com
• http://chainradar.com

Onion Monero Blockchain Explorer features

The key features of the Onion Monero Blockchain Explorer are:

• 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 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 and mixins belong to the given Monero address and viewkey,
• the only explorer that can be used to prove that you send Monero to someone,
• 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,
• the only explorer supporting Monero testnet network,
• the only explorer providing tx checker and pusher for online pushing of transactions,
• the only explorer able to estimate possible spendings based on address and viewkey,
• the only explorer that can provide total amount of all miner fees.

Compilation on Ubuntu 16.04

Compile latest Monero

Download and compile recent Monero release into your home folder:

# first install monero dependecines
sudo apt update

sudo apt install git build-essential cmake libboost-all-dev miniupnpc libunbound-dev graphviz doxygen libunwind8-dev pkg-config libssl-dev libcurl4-openssl-dev libgtest-dev

# go to home folder 
cd ~

git clone https://github.com/monero-project/monero

cd monero/

# checkout last monero version
git checkout -b last_release v0.10.3.1

make

Compile and run the explorer

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

# go to home folder if still in ~/monero
cd ~

# 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

# make a build folder and enter it
mkdir build && cd build

# create the makefile
cmake ..

# altearnatively can use: cmake -DMONERO_DIR=/path/to/monero_folder .. 
# if monero is not in ~/monero

# compile
make

When compilation finishes executable xmrblocks should be created. Before running please make sure that ~/Downloads folder exists and is writable. Time zone library that explorer is using, puts there its database of time zone offsets

To run it:

./xmrblocks

By default it will look for blockchain in its default location i.e., ~/.bitmonero/lmdb. You can use --bc-path option if its in different location. 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

The explorer's command line options

xmrblocks, Onion Monero Blockchain Explorer:
  -h [ --help ] [=arg(=1)] (=0)         produce help message
  -t [ --testnet ] [=arg(=1)] (=0)      use testnet blockchain
  --enable-pusher [=arg(=1)] (=0)       enable signed transaction pusher
  --enable-mixin-details [=arg(=1)] (=0)
                                        enable mixin details for key images, 
                                        e.g., timescale, mixin of mixins, in tx
                                        context
  --enable-key-image-checker [=arg(=1)] (=0)
                                        enable key images file checker
  --enable-output-key-checker [=arg(=1)] (=0)
                                        enable outputs key file checker
  --enable-json-api arg (=1)            enable JSON REST api
  --enable-tx-cache [=arg(=1)] (=0)     enable caching of transaction details
  --show-cache-times [=arg(=1)] (=0)    show times of getting data from cache 
                                        vs no cache
  --enable-block-cache [=arg(=1)] (=0)  enable caching of block details
  --enable-autorefresh-option [=arg(=1)] (=0)
                                        enable users to have the index page on 
                                        autorefresh
  --enable-emission-monitor [=arg(=1)] (=0)
                                        enable Monero total emission monitoring
                                        thread
  -p [ --port ] arg (=8081)             default explorer port
  --testnet-url arg                     you can specify testnet url, if you run
                                        it on mainnet. link will show on front 
                                        page to testnet explorer
  --mainnet-url arg                     you can specify mainnet url, if you run
                                        it on testnet. link will show on front 
                                        page to mainnet explorer
  --no-blocks-on-index arg (=10)        number of last blocks to be shown on 
                                        index page
  --network-info-timeout arg (=1000)    maximum time, in milliseconds, to wait 
                                        for network info availability
  --mempool-info-timeout arg (=5000)    maximum time, in milliseconds, to wait 
                                        for mempool data for the front page
  --mempool-refresh-time arg (=10)      time, in seconds, for each refresh of 
                                        mempool state
  -b [ --bc-path ] arg                  path to lmdb folder of the blockchain, 
                                        e.g., ~/.bitmonero/lmdb
  --ssl-crt-file arg                    path to crt file for ssl (https) 
                                        functionality
  --ssl-key-file arg                    path to key file for ssl (https) 
                                        functionality
  -d [ --deamon-url ] arg (=http:://127.0.0.1:18081)
                                        Monero deamon url

Example usage, defined as bash aliases.

# for mainnet explorer
alias xmrblocksmainnet='~/onion-monero-blockchain-explorer/build/xmrblocks    --port 8081 --no-blocks-on-index 24 --testnet-url "http://139.162.32.245:8082" --enable-pusher --enable-emission-monitor'

# for testnet explorer
alias xmrblockstestnet='~/onion-monero-blockchain-explorer/build/xmrblocks -t --port 8082 --no-blocks-on-index 24 --mainnet-url "http://139.162.32.245:8081" --enable-pusher --enable-emission-monitor'

These are aliases similar to those used for http://139.162.32.245:8081/ and http://139.162.32.245:8082/, respectively.

Enable Monero emission

Obtaining current Monero emission amount is not straight forward. Thus, by default it is disabled. To enable it use --enable-emission-monitor flag, e.g.,

xmrblocks --enable-emission-monitor 

This flag will enable emission monitoring thread. When started, the thread will initially scan the entire blockchain, and calculate the cumulative emission based on each block. Since it is a separate thread, the explorer will work as usual during this time. Every 10000 blocks, the thread will save current emission in a file, by default, in ~/.bitmonero/lmdb/emission_amount.txt. For testnet network, it is ~/.bitmonero/testnet/lmdb/emission_amount.txt. This file is used so that we don't need to rescan entire blockchain whenever the explorer is restarted. When the explorer restarts, the thread will first check if ~/.bitmonero/lmdb/emission_amount.txt is present, read its values, and continue from there if possible. Subsequently, only the initial use of the tread is time consuming. Once the thread scans the entire blockchain, it updates the emission amount using new blocks as they come. Since the explorer writes this file, there can be only one instance of it running for mainnet and testnet. Thus, for example, you cant have two explorers for mainnet running at the same time, as they will be trying to write and read the same file at the same time, leading to unexpected results. Off course having one instance for mainnet and one instance for testnet is fine, as they write to different files.

When the emission monitor is enabled, information about current emission of coinbase and fees is displayed on the front page, e.g., :

Monero emission (fees) is 14485540.430 (52545.373) as of 1313448 block

The values given, can be checked using Monero daemon's print_coinbase_tx_sum command. For example, for the above example: print_coinbase_tx_sum 0 1313449.

To disable the monitor, simply restart the explorer without --enable-emission-monitor flag.

Enable SSL (https)

By default, the explorer does not use ssl. But it has such a functionality.

As an example, you can generate your own ssl certificates as follows:

cd /tmp # example folder
openssl genrsa -out server.key 1024
openssl req -new -key server.key -out server.csr
openssl x509 -req -days 3650 -in server.csr -signkey server.key -out server.crt

Having the crt and key files, run xmrblocks in the following way:

./xmrblocks --ssl-crt-file=/tmp/server.crt --ssl-key-file=/tmp/server.key 

Note: Because we generated our own certificate, modern browsers will complain about it as they cant verify the signatures against any third party. So probably for any practical use need to have properly issued ssl certificates.

JSON API

The explorer has JSON api. For the API, it uses conventions defined by JSend.

api/transaction/<tx_hash>

curl  -w "\n" -X GET "http://139.162.32.245:8081/api/transaction/6093260dbe79fd6277694d14789dc8718f1bd54457df8bab338c2efa3bb0f03d"

Partial results shown:

{
  "data": {
    "block_height": 1268252,
    "coinbase": false,
    "confirmations": 1,
    "current_height": 1268253,
    "extra": "01be23e277aed6b5f41f66b05244bf994c13108347366ec678ae16657f0fc3a22b",
    "inputs": [
      {
        "amount": 0,
        "key_image": "67838fd0ffd79f13e735830d3ec60412aed59e53e1f997feb6f73d088b949611",
        "mixins": [
          {
            "block_no": 1238623,
            "public_key": "0a5b853c55303c10e1326acfb085b9e246e088b1ccac7e37f7a810d46a28a914"
          },
          {
            "block_no": 1246942,
            "public_key": "527cf86f5abbfb006c970f7c6eb40493786d4751306f8985c6a43f98a88c0dff"
          }
        ]
      }
    ],
    "mixin": 9,
    "outputs": [
      {
        "amount": 0,
        "public_key": "525779873776e4a42f517fd79b72e7c31c3ba03e730fc32287f6414fb702c1d7"
      },
      {
        "amount": 0,
        "public_key": "e25f00fceb77af841d780b68647618812695b4ca6ebe338faba6e077f758ac30"
      }
    ],
    "payment_id": "",
    "payment_id8": "",
    "rct_type": 1,
    "timestamp": 1489753456,
    "timestamp_utc": "2017-03-17 12:24:16",
    "tx_fee": 12517785574,
    "tx_hash": "6093260dbe79fd6277694d14789dc8718f1bd54457df8bab338c2efa3bb0f03d",
    "tx_size": 13323,
    "tx_version": 2,
    "xmr_inputs": 0,
    "xmr_outputs": 0
  },
  "status": "success"
}

api/transactions

Transactions in last 25 blocks

curl  -w "\n" -X GET "http://139.162.32.245:8081/api/transactions"

Partial results shown:

{
  "data": {
    "blocks": [
      {
        "age": "33:16:49:53",
        "height": 1268252,
        "size": 105390000000000000,
        "timestamp": 1489753456,
        "timestamp_utc": "2017-03-17 12:24:16",
        "txs": [
          {
            "coinbase": true,
            "mixin": 0,
            "outputs": 8491554678365,
            "rct_type": 0,
            "tx_fee": 0,
            "tx_hash": "7c4286f64544568265bb5418df84ae69afaa3567749210e46f8340c247f4803f",
            "tx_size": 151000000000000,
            "tx_version": 2
          },
          {
            "coinbase": false,
            "mixin": 5,
            "outputs": 0,
            "rct_type": 2,
            "tx_fee": 17882516700,
            "tx_hash": "2bfbccb918ee5f050808dd040ce03943b7315b81788e9cdee59cf86b557ba48c",
            "tx_size": 19586000000000000,
            "tx_version": 2
          }
        ]
      }
    ],
    "limit": 25,
    "page": 0
  },
  "status": "success"
}

api/transactions?page=<page_no>&limit=<tx_per_page>

curl  -w "\n" -X GET "http://139.162.32.245:8081/api/transactions?page=2&limit=10"

Result analogical to the one above.

api/block/<block_number|block_hash>

curl  -w "\n" -X GET "http://139.162.32.245:8081/api/block/1293257"

Partial results shown:

{
  "data": {
    "block_height": 1293257,
    "block_reward": 0,
    "current_height": 1293264,
    "hash": "9ef6bb8f9b8bd253fc6390e5c2cdc45c8ee99fad16447437108bf301fe6bd6e1",
    "size": 141244,
    "timestamp": 1492761974,
    "timestamp_utc": "2017-04-21 08:06:14",
    "txs": [
      {
        "coinbase": true,
        "extra": "018ae9560eb85d5ebd22d3beaed55c21d469eab430c5e3cac61b3fe2f5ad156770020800000001a9030800",
        "mixin": 0,
        "payment_id": "",
        "payment_id8": "",
        "rct_type": 0,
        "tx_fee": 0,
        "tx_hash": "3ff71b65bec34c9261e01a856e6a03594cf0472acf6b77db3f17ebd18eaa30bf",
        "tx_size": 95,
        "tx_version": 2,
        "xmr_inputs": 0,
        "xmr_outputs": 8025365394426
      }
    ]
  },
  "status": "success"
}

api/mempool

Return all txs in the mempool.

curl  -w "\n" -X GET "http://139.162.32.245:8081/api/mempool"

Partial results shown:

{
  "data": {
    "limit": 100000000,
    "page": 0,
    "total_page_no": 0,
    "txs": [
      {
        "coinbase": false,
        "extra": "022100325f677d96f94155a4840a84d8e0c905f7a4697a25744633bcb438feb1e51fb2012eda81bf552c53c2168f4130dbe0265c3a7898f3a7eee7c1fed955a778167b5d",
        "mixin": 3,
        "payment_id": "325f677d96f94155a4840a84d8e0c905f7a4697a25744633bcb438feb1e51fb2",
        "payment_id8": "",
        "rct_type": 2,
        "timestamp": 1494470894,
        "timestamp_utc": "2017-05-11 02:48:14",
        "tx_fee": 15894840000,
        "tx_hash": "9f3374f8ac67febaab153eab297937a3d0d2c706601e496bf5028146da0c9aef",
        "tx_size": 13291,
        "tx_version": 2,
        "xmr_inputs": 0,
        "xmr_outputs": 0
      }
    ],
    "txs_no": 7
  },
  "status": "success"
}

Limit of 100000000 is just default value above to ensure that all mempool txs are fetched if no specific limit given.

api/mempool?limit=<no_of_top_txs>

Return number of newest mempool txs, e.g., only 10.

curl  -w "\n" -X GET "http://139.162.32.245:8081/api/mempool?limit=10"

Result analogical to the one above.

api/search/<block_number|tx_hash|block_hash>

curl  -w "\n" -X GET "http://139.162.32.245:8081/api/search/1293669"

Partial results shown:

{
  "data": {
    "block_height": 1293669,
    "current_height": 1293670,
    "hash": "5d55b8fabf85b0b4c959d66ad509eb92ddfe5c2b0e84e1760abcb090195c1913",
    "size": 118026,
    "timestamp": 1492815321,
    "timestamp_utc": "2017-04-21 22:55:21",
    "title": "block",
    "txs": [
      {
        "coinbase": true,
        "extra": "01cb7fda09033a5fa06dc601b9295ef3790397cf3c645e958e34cf7ab699d2f5230208000000027f030200",
        "mixin": 0,
        "payment_id": "",
        "payment_id8": "",
        "rct_type": 0,
        "tx_fee": 0,
        "tx_hash": "479ba432f5c88736b438dd4446a11a13046a752d469f7828151f5c5b86be4e9a",
        "tx_size": 95,
        "tx_version": 2,
        "xmr_inputs": 0,
        "xmr_outputs": 7992697599717
      }
    ]
  },
  "status": "success"
}

api/outputs?txhash=<tx_hash>&address=&viewkey=&txprove=<0|1>

For txprove=0 we check which outputs belong to given address and corresponding viewkey. For txprove=1 we use to prove to the recipient that we sent them founds. For this, we use recipient's address and our tx private key as a viewkey value, i.e., viewkey=<tx_private_key>

Checking outputs:

# we use here official Monero project's donation address as an example
curl  -w "\n" -X GET "http://139.162.32.245:8081/api/outputs?txhash=17049bc5f2d9fbca1ce8dae443bbbbed2fc02f1ee003ffdd0571996905faa831&address=44AFFq5kSiGBoZ4NMDwYtN18obc8AemS33DBLWs3H7otXft3XjrpDtQGv7SqSsaBYBb98uNbr2VBBEt7f2wfn3RVGQBEP3A&viewkey=f359631075708155cc3d92a32b75a7d02a5dcf27756707b47a2b31b21c389501&txprove=0"

{
  "data": {
    "address": "42f18fc61586554095b0799b5c4b6f00cdeb26a93b20540d366932c6001617b75db35109fbba7d5f275fef4b9c49e0cc1c84b219ec6ff652fda54f89f7f63c88",
    "outputs": [
      {
        "amount": 34980000000000,
        "match": true,
        "output_idx": 0,
        "output_pubkey": "35d7200229e725c2bce0da3a2f20ef0720d242ecf88bfcb71eff2025c2501fdb"
      },
      {
        "amount": 0,
        "match": false,
        "output_idx": 1,
        "output_pubkey": "44efccab9f9b42e83c12da7988785d6c4eb3ec6e7aa2ae1234e2f0f7cb9ed6dd"
      }
    ],
    "tx_hash": "17049bc5f2d9fbca1ce8dae443bbbbed2fc02f1ee003ffdd0571996905faa831",
    "tx_prove": false,
    "viewkey": "f359631075708155cc3d92a32b75a7d02a5dcf27756707b47a2b31b21c389501"
  },
  "status": "success"
}

Proving transfer:

We use recipient's address (i.e. not our address from which we sent xmr to recipient). For the viewkey, we use tx_private_key (although the GET variable is still called viewkey) that we obtained by sending this txs.

# this is for testnet transaction 
curl  -w "\n" -X GET "http://139.162.32.245:8082/api/outputs?txhash=94782a8c0aa8d8768afa0c040ef0544b63eb5148ca971a024ac402cad313d3b3&address=9wUf8UcPUtb2huK7RphBw5PFCyKosKxqtGxbcKBDnzTCPrdNfJjLjtuht87zhTgsffCB21qmjxjj18Pw7cBnRctcKHrUB7N&viewkey=e94b5bfc599d2f741d6f07e3ab2a83f915e96fb374dfb2cd3dbe730e34ecb40b&txprove=1"

{
  "data": {
    "address": "71bef5945b70bc0a31dbbe6cd0bd5884fe694bbfd18fff5f68f709438554fb88a51b1291e378e2f46a0155108782c242cc1be78af229242c36d4f4d1c4f72da2",
    "outputs": [
      {
        "amount": 1000000000000,
        "match": true,
        "output_idx": 0,
        "output_pubkey": "c1bf4dd020b5f0ab70bd672d2f9e800ea7b8ab108b080825c1d6cfc0b7f7ee00"
      },
      {
        "amount": 0,
        "match": false,
        "output_idx": 1,
        "output_pubkey": "8c61fae6ada2a103565dfdd307c7145b2479ddb1dab1eaadfa6c34db65d189d5"
      }
    ],
    "tx_hash": "94782a8c0aa8d8768afa0c040ef0544b63eb5148ca971a024ac402cad313d3b3",
    "tx_prove": true,
    "viewkey": "e94b5bfc599d2f741d6f07e3ab2a83f915e96fb374dfb2cd3dbe730e34ecb40b"
  },
  "status": "success"
}

Result analogical to the one above.

api/networkinfo

curl  -w "\n" -X GET "http://139.162.32.245:8081/api/networkinfo"

{
  "data": {
    "alt_blocks_count": 0,
    "block_size_limit": 600000,
    "cumulative_difficulty": 2091549555696348,
    "difficulty": 7941560081,
    "fee_per_kb": 303970000,
    "grey_peerlist_size": 4991,
    "hash_rate": 66179667,
    "height": 1310423,
    "incoming_connections_count": 0,
    "outgoing_connections_count": 5,
    "start_time": 1494822692,
    "status": "OK",
    "target": 120,
    "target_height": 0,
    "testnet": false,
    "top_block_hash": "76f9e85d62415312758bc09e0b9b48fd2b005231ad1eee435a8081e551203f82",
    "tx_count": 1219048,
    "tx_pool_size": 2,
    "white_peerlist_size": 1000
  },
  "status": "success"
}

api/emission

curl  -w "\n" -X GET "http://139.162.32.245:8081/api/emission"

{
  "data": {
    "blk_no": 1313969,
    "coinbase": 14489473877253413000,
    "fee": 52601974988641130
  },
  "status": "success"
}

Emission only works when the emission monitoring thread is enabled.

api/rawblock/<block_number|block_hash>

Return raw json block data, as represented in Monero.

curl  -w "\n" -X GET "http://139.162.32.245:8081/api/rawblock/1293257"

Example result not shown.

api/rawtransaction/<tx_hash>

Return raw json tx data, as represented in Monero.

curl  -w "\n" -X GET "http://139.162.32.245:8081/api/rawtransaction/6093260dbe79fd6277694d14789dc8718f1bd54457df8bab338c2efa3bb0f03d"

Example result not shown.

Other monero 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.