Parking: Front-end

See the project in action at this website. The contract is deployed on the Rinkeby test network, so you can use test ethers when you check it out. If you don't have any, you can get some free Rinkeby ethers here.

The idea

A distributed webapplication (or dapp) for a new parking system using the Ethereum network. More specifically, we want a smart contract on the Etherium blockchain on which anyone can register their car when they park. Secondly we want to create a user-friendly interface to interact with that contract and simplify the registration process. It brings parking your car to the twenty first century!

Using this online user interface anyone can easily register their parked car on their phone and pay with parking tokens. Those parking tokens can even be bought beforehand with ether.

The implementation

The application was made by lab9k especially for the city of Ghent.

Registrations of the 'Park' event on the ethereum contract are automatically caught by the REST api. A simple GET request to this api will return all the registered timestamps for each region for a given license plate. Discover more at our other repository: lab9k/ParkingREST.

The contract

The backbone of our dapp is our smart contract, via which anyone can buy parking tokens and paying for parking with those.

Our smart contract contains the following methods:

For admin:
- kill() - selfdestructs the contract
- updateRegio(uint regio, uint price) - changes the tariff of a zone
- setPrices(uint256 newBuyPrice) - change the price of a park token by given the amount of tokens you get for 1 ether
For anyone:
- isOwner(address toCheck) returns (bool) - return true if the supplied address is the owner of the contract, otherwise false
- park(string nummerplaatEncrypted, uint regio, uint tokens) returns (bool succes) - allows someone to park their car in a zone if they have enough tokens and have encrypted their license plate with the public key
- transfer(address to, uint256 amount) returns (bool) - transfer tokens to another address, return true if successful
- buy() payable returns (bool succes) - send ether to the contract to buy parking tokens

and following public fields:

string public name;
string public symbol;
uint8 public decimals;
uint256 public totalSupply;
uint public buyPrice;
mapping(address => uint) public balances;
mapping(uint => uint) public regios;
mapping(uint => mapping(bytes32 => uint)) public tickets;

and lastly these events that anyone can listen to:

event Transfer(address indexed _from, address indexed _to, uint256 _value);
event Buy(address who, uint tokens);
event Park(string nummerplaatEncrypted, bytes32 key);

MapIt

The front-end strives to make everything as easy as possible for everyone. One way to achieve this is by automatically detecting the parking zone of the location specified by the user, using our own MapIt deployment. Ofcourse the user can also let our dapp calculate their location automatically if the give their permission. Aside from all the current parking zones the server also has information on the bounderies of the 25 official districts of Ghent.

Interaction with MapIt goes via http get requests and returns json by default. The most common query is a lookup by point. With the following format: https://mapit.lab9k.gent/point/[SRID]/[x],[y], where SRID is a unique number referring to a particular co-ordinate system; the one you probably are interested in is 4326 for WGS84 normal lon/lat. x and y are the co-ordinates of the point in the co-ordinate system. Note that Mapit works with longitude, latitude in contrast to many other services like google maps where they use latitude, longitude. So x is longitude and y is latitude!

Here is an example URL:

https://mapit.lab9k.gent/point/4326/3.735406,51.048912

This returns the following json:

{
    "26": {
        "parent_area": null,
        "generation_high": 1,
        "all_names": {},
        "id": 26,
        "codes": {},
        "name": "Binnenstad",
        "country": "BE",
        "type_name": "Wijken",
        "generation_low": 1,
        "country_name": "België",
        "type": "WIJK"
    },
    "51": {
        "parent_area": null,
        "generation_high": 1,
        "all_names": {},
        "id": 51,
        "codes": {},
        "name": "zone11",
        "country": "BE",
        "type_name": "rood",
        "generation_low": 1,
        "country_name": "België",
        "type": "RED"
    }
}

From the json we can extrapolate that the coordinate is situated in distric (WIJK) "Binnenstad" and parking zone RED. With that last bit of information we can ask the contract for the tariff that applies within the RED zone.

More specifics about the MapIt API can be found at the official website of Global MapIt.

Technologies

Node.js - Platform for API & Server
Express.js - Regulates exchange between API and DB
Jsencypt.js - Encryption of license plates
Node-rsa.js - Decryption of license plates
Web3.js - Regulates exchange between API and Ethereum contracts
MongoDB - Stores all the license plates

Architecture

Authors

Hans Fraiponts
Ruben Alliet
Wannes Vereecken
Jef Willems
Pieter-jan Philips
Tom Lauwaerts
Michiel Derveeuw

License

This project is licensed under the MIT License

lab9k/ParkCoin