Create ServiceDiscovery mechanism

[ChristianKniep]

Develop mechanism to add/list services to blockchain and reference to IPFS

[ChristianKniep]

[ravs1]

A very basic POC on user perspective of services offered.

Scope

1. Service provided by the service provider.

2. User subscribe the service.

3. Service provider charge for the service.

4. User sees how much to pay.

5. User can unsubscribe the service if there are no dues to be paid .

I used mist wallet to push contracts to the blockchain and atom to write the solidity contracts.

No connectivity with IPFS

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Contract

pragma solidity ^0.4.2;

contract mortal{ // address is a pre defined variable in solidity

address public owner;

//constructor without any arguments

function mortal(){

__//msg is predefined object in solidity__
__//compiler takes address of the sender of contract__
__//and place it in the owner.__

owner = msg.sender;
}

__//modifier will put restrictions__
__//only owner can access the kill function__
__//not the contracts that are inheriting this contract.__

  modifier onlyOwner{
  if(msg.sender != owner){
    throw;
  }
  else{
    _ ; __// this means that modifier will pass to function kill.__
  }
}

__//cant delete something which is in the blockchain__
__//but can surely stop it and this is done by kill().__
__//onlyOwner modifier is used which makes the function kill__
__//executed by only the owner.__

function kill() onlyOwner{

  __//it is a predefined function .__
  __//will return the leftover ether to the owner.__

  suicide(owner);
}

}

// User Contract //this exhibits inheritence //contract User now has all the functionlity of mortal

contract User is mortal { string public userName;

//mapping services corresponds to address

mapping(address => Service) public services;

//user need to be associated with different services //service can be anything offered

struct Service{
bool active; __// whether subscribed a service or not__
uint lastUpdate; __// when did the user last time interacted with the service.__
uint256 debt; __// ether transfer__

} function User(string _name){ userName = _name; }

//function making user to register with the provider who is providing the service //only the user contract owner will be able to register with the service provider.

function registerToProvider(address _providerAddress) onlyOwner{

__//array of services for that provider address and the things that it should exhibit.__
services[_providerAddress] = Service({
   active:true,
   lastUpdate:now,
   debt:0
  });

}

//setting up the cost of services

  function setDebt(uint256 _debt){

__//it will find the address of the service provider and will check whether__
__//the service is active or not.__
__//msg.sender is the address of the provider__
__//user cannot use this function__

if(services[msg.sender].active){
  services[msg.sender].lastUpdate = now;
  services[msg.sender].debt       = _debt;

}
else{
  throw;
}

}

//paying the fee

function payToProvider(address _providerAddress){ _providerAddress.send(services[_providerAddress].debt);

}

//unsubscribing from the service

function unSubscribe(address _providerAddress){
if(services[_providerAddress.debt == 0]){
  services[_providerAddress].active = false;
}
else{
  throw;
}

} }

//Service Provider Contract

contract Provider is mortal{ string public providerName; string public description;

function Provider(string _name,string _description){ providerName = _name; description = _description; }

//providing the provider the prevelidge to access setDebt function. //provider is setting up the debt of the specific user address

function setDebt(uint256 _debt, address _userAddress){

__//creating the object of User contract__

User person = User(_userAddress);
person.setDebt(_debt);

} }