├── abi.json
├── Faucet.sol
├── .gitignore
├── README.md
└── index.html


/abi.json:
--------------------------------------------------------------------------------
 1 | [
 2 | 	{
 3 | 		"anonymous": false,
 4 | 		"inputs": [
 5 | 			{
 6 | 				"indexed": true,
 7 | 				"internalType": "address",
 8 | 				"name": "from",
 9 | 				"type": "address"
10 | 			},
11 | 			{
12 | 				"indexed": false,
13 | 				"internalType": "uint256",
14 | 				"name": "amount",
15 | 				"type": "uint256"
16 | 			}
17 | 		],
18 | 		"name": "Deposit",
19 | 		"type": "event"
20 | 	},
21 | 	{
22 | 		"anonymous": false,
23 | 		"inputs": [
24 | 			{
25 | 				"indexed": true,
26 | 				"internalType": "address",
27 | 				"name": "to",
28 | 				"type": "address"
29 | 			}
30 | 		],
31 | 		"name": "Withdrawal",
32 | 		"type": "event"
33 | 	},
34 | 	{
35 | 		"inputs": [],
36 | 		"name": "destroy",
37 | 		"outputs": [],
38 | 		"stateMutability": "nonpayable",
39 | 		"type": "function"
40 | 	},
41 | 	{
42 | 		"stateMutability": "payable",
43 | 		"type": "receive"
44 | 	},
45 | 	{
46 | 		"inputs": [],
47 | 		"name": "withdraw",
48 | 		"outputs": [],
49 | 		"stateMutability": "nonpayable",
50 | 		"type": "function"
51 | 	},
52 | 	{
53 | 		"inputs": [],
54 | 		"stateMutability": "nonpayable",
55 | 		"type": "constructor"
56 | 	}
57 | ]


--------------------------------------------------------------------------------
/Faucet.sol:
--------------------------------------------------------------------------------
 1 | // SPDX-License-Identifier: MIT
 2 | // Author: Jacob Suchorabski
 3 | pragma solidity >= 0.7.0 <= 0.7.4;
 4 | 
 5 | contract Faucet{
 6 |     
 7 |     address owner;
 8 |     mapping (address => uint) timeouts;
 9 |     
10 |     event Withdrawal(address indexed to);
11 |     event Deposit(address indexed from, uint amount);
12 |     
13 |     constructor() {
14 |         //Will be called on creation of the smart contract.
15 |         owner = msg.sender;
16 |     }
17 |     
18 |     //  Sends 0.1 ETH to the sender when the faucet has enough funds
19 |     //  Only allows one withdrawal every 30 mintues
20 |     function withdraw() external{
21 |         
22 |         require(address(this).balance >= 0.1 ether, "This faucet is empty. Please check back later.");
23 |         require(timeouts[msg.sender] <= block.timestamp - 30 minutes, "You can only withdraw once every 30 minutes. Please check back later.");
24 |         
25 |         msg.sender.transfer(0.1 ether);
26 |         timeouts[msg.sender] = block.timestamp;
27 |         
28 |         emit Withdrawal(msg.sender);
29 |     }
30 |     
31 |     //  Sending Tokens to this faucet fills it up
32 |     receive() external payable {
33 |         emit Deposit(msg.sender, msg.value); 
34 |     } 
35 |     
36 |     
37 |     //  Destroys this smart contract and sends all remaining funds to the owner
38 |     function destroy() public{
39 |         require(msg.sender == owner, "Only the owner of this faucet can destroy it.");
40 |         selfdestruct(msg.sender);
41 |     }
42 | }
43 | 


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/.gitignore:
--------------------------------------------------------------------------------
  1 | 
  2 | # Created by https://www.toptal.com/developers/gitignore/api/solidity,macos
  3 | # Edit at https://www.toptal.com/developers/gitignore?templates=solidity,macos
  4 | 
  5 | ### macOS ###
  6 | # General
  7 | .DS_Store
  8 | .AppleDouble
  9 | .LSOverride
 10 | 
 11 | # Icon must end with two \r
 12 | Icon
 13 | 
 14 | 
 15 | # Thumbnails
 16 | ._*
 17 | 
 18 | # Files that might appear in the root of a volume
 19 | .DocumentRevisions-V100
 20 | .fseventsd
 21 | .Spotlight-V100
 22 | .TemporaryItems
 23 | .Trashes
 24 | .VolumeIcon.icns
 25 | .com.apple.timemachine.donotpresent
 26 | 
 27 | # Directories potentially created on remote AFP share
 28 | .AppleDB
 29 | .AppleDesktop
 30 | Network Trash Folder
 31 | Temporary Items
 32 | .apdisk
 33 | 
 34 | ### Solidity ###
 35 | # Logs
 36 | logs
 37 | *.log
 38 | npm-debug.log*
 39 | yarn-debug.log*
 40 | yarn-error.log*
 41 | lerna-debug.log*
 42 | 
 43 | # Diagnostic reports (https://nodejs.org/api/report.html)
 44 | report.[0-9]*.[0-9]*.[0-9]*.[0-9]*.json
 45 | 
 46 | # Runtime data
 47 | pids
 48 | *.pid
 49 | *.seed
 50 | *.pid.lock
 51 | 
 52 | # Directory for instrumented libs generated by jscoverage/JSCover
 53 | lib-cov
 54 | 
 55 | # Coverage directory used by tools like istanbul
 56 | coverage
 57 | *.lcov
 58 | 
 59 | # nyc test coverage
 60 | .nyc_output
 61 | 
 62 | # Grunt intermediate storage (https://gruntjs.com/creating-plugins#storing-task-files)
 63 | .grunt
 64 | 
 65 | # Bower dependency directory (https://bower.io/)
 66 | bower_components
 67 | 
 68 | # node-waf configuration
 69 | .lock-wscript
 70 | 
 71 | # Compiled binary addons (https://nodejs.org/api/addons.html)
 72 | build/Release
 73 | 
 74 | # Dependency directories
 75 | node_modules/
 76 | jspm_packages/
 77 | 
 78 | # TypeScript v1 declaration files
 79 | typings/
 80 | 
 81 | # TypeScript cache
 82 | *.tsbuildinfo
 83 | 
 84 | # Optional npm cache directory
 85 | .npm
 86 | 
 87 | # Optional eslint cache
 88 | .eslintcache
 89 | 
 90 | # Microbundle cache
 91 | .rpt2_cache/
 92 | .rts2_cache_cjs/
 93 | .rts2_cache_es/
 94 | .rts2_cache_umd/
 95 | 
 96 | # Optional REPL history
 97 | .node_repl_history
 98 | 
 99 | # Output of 'npm pack'
100 | *.tgz
101 | 
102 | # Yarn Integrity file
103 | .yarn-integrity
104 | 
105 | # dotenv environment variables file
106 | .env
107 | .env.test
108 | .env*.local
109 | 
110 | # parcel-bundler cache (https://parceljs.org/)
111 | .cache
112 | .parcel-cache
113 | 
114 | # Next.js build output
115 | .next
116 | 
117 | # Nuxt.js build / generate output
118 | .nuxt
119 | dist
120 | 
121 | # Gatsby files
122 | .cache/
123 | # Comment in the public line in if your project uses Gatsby and not Next.js
124 | # https://nextjs.org/blog/next-9-1#public-directory-support
125 | # public
126 | 
127 | # vuepress build output
128 | .vuepress/dist
129 | 
130 | # Serverless directories
131 | .serverless/
132 | 
133 | # FuseBox cache
134 | .fusebox/
135 | 
136 | # DynamoDB Local files
137 | .dynamodb/
138 | 
139 | # TernJS port file
140 | .tern-port
141 | 
142 | # Stores VSCode versions used for testing VSCode extensions
143 | .vscode-test
144 | 
145 | # End of https://www.toptal.com/developers/gitignore/api/solidity,macos
146 | 
147 | 


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/README.md:
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 1 | # Ethereum Faucet
 2 | 
 3 | ## Description
 4 | 
 5 | This project is a basic Ethereum faucet that enables anyone to send Ether to the smart contract to fill it up with funds and you can interact with it through the withdraw function to request 0.1 ETH from the faucet.
 6 | 
 7 | If the faucet has enough funds you will receive 0.1 ETH to your Ethereum address. There is a simple timeout filter built in to only allow one request per 30 minutes.
 8 | 
 9 | ## Key Facts
10 | 
11 | * This code is published under the MIT License
12 | * This code has been deveoped by Jacob Suchorabski
13 | * Solidity (v. 0.7.4) has been used to develop and test the faucet
14 | * You can find the frontend implementation in the `index.html` file which you can use to interface with the smart contract [here](https://svcho.github.io/Ethereum-Faucet/).
15 | 
16 | ## Requirements & Demo
17 | 
18 | This version of the smart contract is deployed on the [Ropsten Testnetwork](https://ropsten.etherscan.io/) and you can find it with the following address:
19 | 
20 | [0x5194d3D2D77585ff89a2823F77C191a93d2F6416](https://ropsten.etherscan.io/address/0x5194d3D2D77585ff89a2823F77C191a93d2F6416)
21 | 
22 | If you want to use the smart contract you will need an Ethereum Wallet that can interact with smart contracts and switch to the Ropsten Testnetwork (Example: [MetaMask](https://metamask.io/)).
23 | 
24 | ## Features
25 | 
26 | ### Variables & Events
27 | 
28 | ```Solidity
29 | address owner;
30 | mapping (address => uint) timeouts;
31 |     
32 | event Withdrawal(address indexed to);
33 | event Deposit(address indexed from, uint amount);
34 |     
35 | constructor() {
36 |     owner = msg.sender;
37 | }
38 | 
39 | function destroy() public{
40 | 		require(msg.sender == owner, "Only the owner of this faucet can destroy it.");
41 | 		selfdestruct(msg.sender);
42 | }
43 | ```
44 | 
45 | * When creating the smart contract the owner will be saved in order to protect the `selfdestruct` method which destroys this smart contract and sends all remaining funds of the contract to the sender.
46 | * The `timeouts` hash map is used to track which address already used this faucet at which timestamp.
47 | * `Withdrawal` and `Deposit` are events that will be called in the functions described below to make sure that we store our transactions in the transaction log which can be accessed through the blockchain.
48 | 
49 | ### Withdrawing Ether
50 | 
51 | ```Solidity
52 | function withdraw() external{
53 | 
54 |     require(address(this).balance >= 0.1 ether, "This faucet is empty. Please check back later.");
55 |     require(timeouts[msg.sender] <= block.timestamp - 30 minutes, "You can only withdraw once every 30 minutes. Please check back later.");
56 | 
57 |     msg.sender.transfer(0.1 ether);
58 |     timeouts[msg.sender] = block.timestamp;
59 | 
60 |     emit Withdrawal(msg.sender);
61 |     
62 | }
63 | ```
64 | 
65 | * We are checking for two simple requirements in this project
66 |   * Does this smart contract have enough funds? (This smart contract always sends exactly 0.1 ETH)
67 |   * Did the sender already request a withdrawal in the last 30 minutes? (Checked using the timestamp of the current block of the transaction)
68 | * If those conditions are met 0.1 ETH are sent to the `msg.sender` which is the entity calling the smart contract
69 | * Finally the current timestamp is added to our `timeouts` hashmap
70 | 
71 | ### Donating Ether
72 | 
73 | ```Solidity
74 | receive() external payable {
75 | 		emit Deposit(msg.sender, msg.value); 
76 | } 
77 | ```
78 | 
79 | * Ether can be donated by anyone by simply sending Ether to the smart contract
80 | * The `receive()` function is a default function that is payable so it can receive funds. You could also leave this function empty but since we want donations to be visible in the transaction log we are emitting our defined event.
81 | 


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/index.html:
--------------------------------------------------------------------------------
  1 | <!DOCTYPE html>
  2 | <html lang="en">
  3 | <head>
  4 |     <meta charset="utf-8">
  5 |     <meta http-equiv="X-UA-Compatible" content="IE=edge">
  6 |     <meta name="viewport" content="width=device-width, initial-scale=1">
  7 |     <meta name="description" content="Ropsten Testnet Faucet for Ethereum">
  8 |     <meta name="author" content="Jacob Suchorabski">
  9 |     <link rel="canonical" href="https://getbootstrap.com/docs/3.3/examples/navbar/">
 10 | 
 11 |     <title>Ropsten Faucet</title>
 12 | 
 13 |     <!-- Latest compiled and minified CSS -->
 14 |     <link rel="stylesheet" href="https://maxcdn.bootstrapcdn.com/bootstrap/3.3.7/css/bootstrap.min.css" integrity="sha384-BVYiiSIFeK1dGmJRAkycuHAHRg32OmUcww7on3RYdg4Va+PmSTsz/K68vbdEjh4u" crossorigin="anonymous">
 15 | 
 16 |     <style>
 17 |         body {
 18 |             padding-top: 70px;
 19 |             padding-bottom: 30px;
 20 |         }
 21 |         .theme-dropdown .dropdown-menu {
 22 |             position: static;
 23 |             display: block;
 24 |             margin-bottom: 20px;
 25 |         }
 26 | 
 27 |         .theme-showcase > p > .btn {
 28 |             margin: 5px 0;
 29 |         }
 30 | 
 31 |         .theme-showcase .navbar .container {
 32 |             width: auto;
 33 |         }
 34 |     </style>
 35 | </head>
 36 | 
 37 | <body>
 38 |     <div class="container theme-showcase" role="main">
 39 |     <div class="jumbotron">
 40 |         <h1>Ethereum Faucet</h1>
 41 |         <p>You can withdraw Ether from this Ropsten Faucet. Make sure to connect your wallet and switch to the Ropsten Testnet.</p>
 42 |         <p>
 43 |             <a class="btn btn-lg btn-primary" role="button" onclick="requestEther()">Request Ether</a>
 44 |             <a class="btn btn-lg btn-success" role="button" onclick="donateEther()">Donate Ether</a>
 45 |         </p>
 46 |     </div>
 47 | 
 48 |     <div class="page-header"><h2>Faucet Data</h2></div>
 49 |     <div>
 50 |         <h3>Contract Address: <a href="https://ropsten.etherscan.io/address/0x5194d3d2d77585ff89a2823f77c191a93d2f6416" target="_blank">0x5194d3D2D77585ff89a2823F77C191a93d2F6416</a></h3>
 51 |         <h3 id="balance">Available Funds: (loading ...)</h3>
 52 |         <h3 id="tx_result" class="text-info"></h3>
 53 |     </div>
 54 | </div>
 55 | 
 56 |     <script src="https://ajax.googleapis.com/ajax/libs/jquery/1.12.4/jquery.min.js"></script>
 57 |     <script src="https://maxcdn.bootstrapcdn.com/bootstrap/3.3.7/js/bootstrap.min.js" integrity="sha384-Tc5IQib027qvyjSMfHjOMaLkfuWVxZxUPnCJA7l2mCWNIpG9mGCD8wGNIcPD7Txa" crossorigin="anonymous"></script>
 58 |     <script src="https://cdn.jsdelivr.net/npm/web3@1.3.1/dist/web3.min.js" crossorigin="anonymous"></script>
 59 | 
 60 |     <script>
 61 |         const contract_address = '0x5194d3D2D77585ff89a2823F77C191a93d2F6416'
 62 |         const contract_abi = [
 63 |             {
 64 |                 "anonymous": false,
 65 |                 "inputs": [
 66 |                     {
 67 |                         "indexed": true,
 68 |                         "internalType": "address",
 69 |                         "name": "from",
 70 |                         "type": "address"
 71 |                     },
 72 |                     {
 73 |                         "indexed": false,
 74 |                         "internalType": "uint256",
 75 |                         "name": "amount",
 76 |                         "type": "uint256"
 77 |                     }
 78 |                 ],
 79 |                 "name": "Deposit",
 80 |                 "type": "event"
 81 |             },
 82 |             {
 83 |                 "anonymous": false,
 84 |                 "inputs": [
 85 |                     {
 86 |                         "indexed": true,
 87 |                         "internalType": "address",
 88 |                         "name": "to",
 89 |                         "type": "address"
 90 |                     }
 91 |                 ],
 92 |                 "name": "Withdrawal",
 93 |                 "type": "event"
 94 |             },
 95 |             {
 96 |                 "inputs": [],
 97 |                 "name": "destroy",
 98 |                 "outputs": [],
 99 |                 "stateMutability": "nonpayable",
100 |                 "type": "function"
101 |             },
102 |             {
103 |                 "stateMutability": "payable",
104 |                 "type": "receive"
105 |             },
106 |             {
107 |                 "inputs": [],
108 |                 "name": "withdraw",
109 |                 "outputs": [],
110 |                 "stateMutability": "nonpayable",
111 |                 "type": "function"
112 |             },
113 |             {
114 |                 "inputs": [],
115 |                 "stateMutability": "nonpayable",
116 |                 "type": "constructor"
117 |             }
118 |         ]
119 | 
120 |         window.addEventListener('load', function () {
121 |             if (typeof web3 !== 'undefined') {
122 |                 web3 = new Web3(window.ethereum)
123 |             } else {
124 |                 web3 = new Web3(new Web3.providers.HttpProvider('http://localhost:8545'));
125 |             }
126 | 
127 |             new Promise((resolve, reject) => {
128 |                 window.ethereum.enable();
129 |                 resolve();
130 |             }).then(() =>{
131 |                 getBalance();
132 |             });
133 |         })
134 | 
135 |         function requestEther(){
136 |             new Promise((resolve, reject) => {
137 |                 getAccounts(function(result) {
138 |                     const Faucet = new web3.eth.Contract(contract_abi, contract_address);
139 |                     Faucet.methods.withdraw().send({from:result[0]},function (error, result){
140 |                         if(!error){
141 |                             document.getElementById("tx_result").innerHTML = "TX created successfully with the hash: " + result;
142 |                         }else{
143 |                             document.getElementById("tx_result").innerHTML = error;
144 |                         }
145 |                     });
146 |                 });
147 |                 resolve();
148 |             });
149 |         }
150 |         function donateEther(){
151 |             var amount = prompt("How much Ether do you want to donate?", "0.5");
152 |             if(isNaN(parseInt(amount))){
153 |                 document.getElementById("tx_result").innerHTML = "Error: Please input a valid number";
154 |             }else{
155 |                 new Promise((resolve) => {
156 |                     getAccounts(function (result) {
157 |                         web3.eth.sendTransaction(
158 |                             {
159 |                                 from: result[0],
160 |                                 to: contract_address,
161 |                                 value: web3.utils.toWei(amount, 'ether')
162 |                             }, function(err, transactionHash) {
163 |                                 if (!err)
164 |                                     document.getElementById("tx_result").innerHTML = "TX created successfully with the hash: " + transactionHash;
165 |                             });
166 |                     });
167 |                 });
168 |             }
169 |         }
170 | 
171 |         function getAccounts(callback) {
172 |             web3.eth.getAccounts((error,result) => {
173 |                 if (error) {
174 |                     console.log(error);
175 |                 } else {
176 |                     callback(result);
177 |                 }
178 |             });
179 |         }
180 |         function getBalance() {
181 |             try {
182 |                 web3.eth.getBalance(contract_address, function (error, wei) {
183 |                     if (!error) {
184 |                         var balance = web3.utils.fromWei(wei, 'ether');
185 |                         document.getElementById("balance").innerHTML = "Available Funds: " + balance + " Ether";
186 |                     }
187 |                 });
188 |             } catch (err) {
189 |                 document.getElementById("balance").innerHTML = err;
190 |             }
191 |         }
192 |     </script>
193 | </body>
194 | </html>
195 | 


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