This project implements an Exchage for trading different cryptocurrencies.

Overview of the webpage

The first webpage is hosted at Github Pages [https://artoriaren.github.io/ExchageSmartContract/](https://artoriaren.github.io/ExchageSmartContract/).

Dependencies

testrpc v6.0.3, truffle 4.1.7, npm, Metamask. This project is developed with Remix, the online Solidity IDE.

Install truffle

npm install -g truffle@4.1.7

In case you need to uninstall truffle, use the following command:

npm uninstall -g truffle

Install testrpc

npm install -g ethereumjs-testrpc --no-optional

How to Run Test

1. In one terminal, run the following command:

   testrpc

2. In another terminal, run the following command:

   truffle test

   This command runs all test files under the /test folder. You should see ouptut like the following figure.

3. To run a particular test file, e.g. 03_trading_simple.js , use the following command:

   truffle test ./test/03_trading_simple.js

How to Run Web Application

Open a terminal and change directory to the root of this project. Use the following command to install all the dependencies in the package.json file.

npm install

If you run into some errors, try npm cache clean and then install again use the above command.

1. In one terminal window, run the following command:

   testrpc

   This project use web3 in Metamask. Please enable Metamask extension and import accounts returned by the above command. Alternatively, you can run testrpc with mnemonics so that you do not have to import new accounts every time.

   testrpc -m '<mnemonics>'

2. To deploy all smart contracts under the /contracts folder, open a second terminal window, change directory to the root of this repo, and run the following commmand:

   truffle migrate

3. To start the web server, open a third terminal window, run the following command:

   npm run dev

   This command will run the scriptdev in the package.json file. It starts the webpack server.

4. Open a web browser and connect to localhost:8080. You will see the webpage displayed.

Test via Browser

Before testing the front-end, make sure to import the first and second accounts to Metamask. Since the first account has been used to deploy smart contracts, its Ether balance will be less than 100. All "FIXED" tokens, 1M, belong to the first accounts. And She is also the owner of the two smart contracts---FixedSupplyToken and Exchange.

Manage Token Tab

1. Send Token

   Fill in "Amount in Token" with 50, "To (Address)" with the second account address. Then click on "Send Token" button. Metamask will pop up a page asking for confirmation. Click on "Confirm".

   You should see an "New Event: Transfer" under the "Events from the Token Contract" label and the "Status from Javascript" displays "Transaction Complete!" on the log panel.

2. Add Token to Exchange

   In the terminal window where you execute truffle migrate previously, copy the address following "FixedSupplyToken:" and paste it to "Address of Token". "Name of the Token" must be given, otherwise it will be an empty string. Then click on "Add Token to Exchange" button. Metamask will pop up a page asking for confirmation. Click on "Confirm".

   You should see an "New Event: TokenAddedToSystem" under the "Events from the Exchange Contract" label on the log panel.

Exchange Overview Tab

1. Display Token and Ether balance

   Token is hard coded to "FIXED", so its balance can only be displayed after you add "FIXED" token to the Exchange on the "Manage Token Tab".

2. Deposit Token

   Step 1. In the "Manage Token" tab, approve the Exchange can spend a certain amount of tokens in our name by filling out the "Approve Token Allowance" table with the Exchange address as "To (address)".

   Step 2. Go to the "Exchange Overview" tab and fill out the "Deposit Token" tab. Notes that the amount should not exceed that filled in Step 1. This will credit the amount of tokens inside the Exchange to our address.

3. Withdraw Token

   Fill the "Withdraw Token" table. You should see token balance displayed at the top of the webpage changes.

If Ether or Token balance is not updated automatically, please refresh the webpage manually.

Fixed Token Trading Tab

Prior to buying and selling any tokens, add the token to the Exchange in the "Manage Token" tab and depoist both token and ether to the Exchange in the "Exchange Overview" tab.

1. Sell Token

Fill the "Sell Token" form in the "Fixed Token Trading" tab. Click on "Sell Token" button.
Metamask will pop up a page asking for confirmation. Click on "Confirm". You should see both update in the "Order Book - Ask" and "Limit orders" event on the log panel.

2. Buy Token

Fill the "Buy Token" form in the "Fixed Token Trading" tab. Click on "Buy Token" button.
Metamask will pop up a page asking for confirmation. Click on "Confirm". Depending on the price of this buy order, it may be fulfilled directly or added to buyOrderBook as a limit order. If it can be fulfilled, you should see "Fulfilled orders" event on the log panel; otherwise, you should see both update in the "Order Book - Bid" and "Limit orders" event on the log panel.

Note

1. Whenever you restart testrpc, run truffle migrate again.
2. Refresh the webpage each time you switch account in Metamask, restart testrpc, or re-run truffle migtrate.
3. The first account created by testrpc is the account used for deploying contracts.
4. Token with the same name cannot be added to our Exchange twice. When testing the addTokenToExchange function, you may need to use truffle migrate --reset to re-deploy the two contracts so that the Exchange has a fresh state.