feat: add data requests post and read functions

.eslintrc

@@ -0,0 +1,32 @@
+{
+  "extends": ["standard"],
+  "env": {
+    "browser": false,
+    "node": true,
+    "jest": true,
+    "mocha": true
+  },
+  "globals" : {
+    "artifacts": false,
+    "contract": false,
+    "assert": false,
+    "web3": false
+  },
+  "rules": {
+    "comma-dangle": ["error", {
+      "arrays": "always-multiline",
+      "objects": "always-multiline",
+      "imports": "always-multiline",
+      "exports": "always-multiline",
+      "functions": "ignore"
+    }],
+    "indent": ["error", 2, {"SwitchCase": 1 }],
+    "jsx-quotes": [2, "prefer-double"],
+    "prefer-promise-reject-errors": 0,
+    "quotes": [2, "double"],
+    "import/export": 0,
+    "no-useless-constructor": 1,
+    "handle-callback-err": 1,
+    "max-len" : ["error", { "code": 120 }]
+  }
+}

.gitignore

@@ -0,0 +1,7 @@
+node_modules/
+build/
+coverage/
+coverage.json
+
+.idea
+.vscode

.soliumignore

@@ -0,0 +1 @@
+node_modules

.soliumrc.json

@@ -0,0 +1,10 @@
+{
+    "extends": "solium:recommended",
+    "plugins": ["security"],
+    "rules": {
+      "quotes": ["error", "double"],
+      "indentation": ["error", 2],
+      "linebreak-style": ["error", "unix"],
+      "error-reason": "off"
+    }
+  }

contracts/Migrations.sol

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+pragma solidity >=0.4.21 <0.6.0;
+
+contract Migrations {
+  address public owner;
+  uint public last_completed_migration;
+
+  constructor() public {
+    owner = msg.sender;
+  }
+
+  modifier restricted() {
+    if (msg.sender == owner) _;
+  }
+
+  function setCompleted(uint completed) public restricted {
+    last_completed_migration = completed;
+  }
+
+  function upgrade(address new_address) public restricted {
+    Migrations upgraded = Migrations(new_address);
+    upgraded.setCompleted(last_completed_migration);
+  }
+}

contracts/WitnetBridgeInterface.sol

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+pragma solidity ^0.5.0;
+
+contract WitnetBridgeInterface {
+
+  struct DataRequest {
+    bytes script;
+    bytes result;
+    uint256 reward;
+  }
+
+  uint256 counter;
+  mapping (uint256 => DataRequest) public requests;
+
+  event PostDataRequest(address indexed _from, uint256 id);
+  event PostResult(address indexed _from, uint256 id);
+
+  constructor () public
+  {
+    counter = 0;
+  }
+
+  function post_dr(bytes memory dr) public payable returns(uint256 id) {
+    id = counter++;
+    requests[id].script = dr;
+    requests[id].result = "";
+    requests[id].reward = msg.value;
+    emit PostDataRequest(msg.sender, id);
+    return id;
+  }
+
+  function read_dr(uint256 id) public view returns(bytes memory dr) {
+    return requests[id].script;
+  }
+
+  function report_result (uint256 id, bytes memory result) public {
+    requests[id].result = result;
+    msg.sender.transfer(requests[id].reward);
+    emit PostResult(msg.sender, id);
+  }
+
+  function read_result (uint256 id) public view returns(bytes memory result){
+    return requests[id].result;
+  }
+}

migrations/1_initial_migration.js

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+const Migrations = artifacts.require("Migrations");
+
+module.exports = function(deployer) {
+  deployer.deploy(Migrations);
+};

migrations/2_deploy_contracts.js

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+var WBI = artifacts.require("./WitnetBridgeInterface.sol")
+
+module.exports = function (deployer, network, accounts) {
+  console.log("Network:", network)
+  deployer.deploy(WBI)
+}

package.json

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+{
+  "name": "witnet-ethereum-bridge",
+  "version": "0.1.0",
+  "description": "Witnet-Ethereum Bridge Interface",
+  "main": "",
+  "scripts": {
+    "test": "truffle test",
+    "console": "truffle console",
+    "postinstall": "npm run compile-contracts",
+    "compile-contracts": "truffle compile --all",
+    "fmt": "solium -d contracts && eslint ./test",
+    "fmt!": "solium -d contracts --fix && eslint ./test --fix",
+    "solium": "solium -d contracts",
+    "solium:fix": "solium -d contracts --fix",
+    "lint": "eslint ./test",
+    "lint:fix": "eslint ./test --fix",
+    "coverage": "solidity-coverage"
+  },
+  "author": "Witnet Foundation <[email protected]>",
+  "repository": {
+    "type": "git",
+    "url": "https://github.com/witnet/witnet-ethereum-bridge.git"
+  },
+  "keywords": [
+    "bridge",
+    "witnet",
+    "ethereum"
+  ],
+  "license": "GPL-3.0",
+  "dependencies": {
+    "truffle-hdwallet-provider": "^1.0.7"
+  },
+  "devDependencies": {
+    "eslint": "^5.16.0",
+    "eslint-config-standard": "^12.0.0",
+    "eslint-plugin-import": "^2.16.0",
+    "eslint-plugin-node": "^8.0.1",
+    "eslint-plugin-promise": "^4.1.1",
+    "eslint-plugin-standard": "^4.0.0",
+    "ethlint": "^1.2.4",
+    "ganache-cli": "^6.4.3",
+    "solidity-coverage": "^0.5.11",
+    "truffle": "^5.0.20",
+    "truffle-assertions": "^0.9.0"
+  }
+}