GitHub Link: https://github.com/henning70/b9lab-final_project_dapp
NOTE: Please ignore the enyojs stuff. I wanted to build my DAPP frontend using the enyojs javascript framework but due to time constraints I did not get too far with it. This is still a full-on truffle project.
Using browser-solidity the contracts worked as expected. From the DAPP most features work as expected but sometimes not quite.
Still to add / issues / vulnerabilities:
- Balance checking of contributors
- Unlocking accounts not included in code yet (for dev/test i unlock all accounts upon geth startup)
- Some erratic behaviour with my if statements in Projects.sol
I'm sure that there are easier more effective ways in coding a funding hub DAPP but I implemented the required functions as explained for the final project.
The contracts:
FundingHub.sol
In addition to the required createProject() function and contribute() function I added a number of other functions.
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createProject(uint256 funding_project_goal, uint funding_project_deadline)
This function will create (deploy) a new Project contract
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contribute(uint _funding_project_id, address _contributor, uint256 _contribution)
This function will call the fund() function of the Project contract for which the contribution is targeted at.
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getProjectCount()
This function will get the number of deployed Project contracts
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getProjectDetails(uint funding_project_id)
This function will get information about a specific Project contract
The contract also has a struct to store information about created projects to keep track of for instance a projects address. I only later realised/remembered that the Project contract should keep track of the projects owner, goal, deadline etc. and updated the Project contract to do so. I have not yet removed this functionality from the FundingHub contract as I found it handy during my development.
The contract also has a number of defined events and a modifier to ensure only the owner can call suicide on the contract.
Project.sol
In addition to the required fund(), payout and refund functions the contract also contains some other functions.
This contracts constructore contains all needed information to keep track of the owner, goal, balance, deadline and status of the project.
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fund(address contributor_address, uint256 contribution_amount)
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payout(address proj_owner, uint256 proj_raised) doPayout
This function will ensure that the raised funds get paid to the owner of the project
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refund(address contributor_address, uint256 contribution_amount) doRefund
This function will ensure refunds are done when the deadline has been reached or goal has been reached
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getContributions(address contributor)
This function will get information about a specific contributor. (not used anymore)
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getProject()
This function will retrieve all information of the project. This information include: owner, goal, raised, deadline and status
The status is used to check if the project is active or not. The project gets a status of Ended if either the deadline has been passed or the goal has been reached.
The contract also has a number of defined events and modifiers.
The contract is far from perfect but does seem to do what it is suppose to do.
The migration script:
2_deploy_contracts.js
I could have opted for a seperate migrations script but decided to modify this script too suit my needs. The migration script, will first deploy the Projects contract. It will then deploy the FundingHub contract and once completed create a new Project contract using the createProject() function from the deployed FundingHub. Once the new Project contract has been deployed, the getProjectDetails() function from the deployed FundingHub will be called to retrieve information of the newly deployed Project contract and then send some wei to the Project contract.
The test
test_refund.js
I wrote a test which is not 100% completed due to time constraints. I was also hampered by timeouts on testnet. Using testrpc did not help either as it continuously gave me out of gas errors. Using my private net I had more luck with the test but just ran out of time to get the refund check done.
The interface:
The inerface consists of three parts, Create project; Contribute and Project details.
Create project:
Consists of 4 fields and a button.
The Project owner field is a drop down list of all accounts discovered from the local running geth instance. Handy for dev/test, but for production use will be a input field.
The Balance field is an input field which will automatically be populated with the selected project owner's account balance.
The Goal field is an input field where the amount of wei can be entered which will represent the amount of funds the project is required to raise.
The Deadline field is an input field where the date/time by which the goal should have been reached can be entered in the format, yyyy-mm-dd HH:MM:SS.sss. The DAPP app.js will convert the value to epoch which is required to compare against the current block timestamp (now) to see if the deadline of the project has passed or not.
The Create project button will initiate project creation.
Contribute:
Consists of 4 fields and a button.
The From field is a drop down list of all accounts discovered from the local running geth instance. Handy for dev/test, but for production use will be a input field. This will be the contributors address.
The Balance field is an input field which will automatically be populated with the selected contributors account balance.
The To field is the address of the project the contributor wants to send his contribution to. The Project details field contains the address of the available projects and can for now be copied from there into this field.
The Amount field is an input field where the amount of wei can be entered which will represent the amount the contributor wants to contribute to the project.
The Contribute button will initiate the contribution.
Project details:
This section contains all information about a specific project. The ID drop down list can be used to select a project. A proper web interface will display the available projects in for instance a grid format for easy selection.
This section displays the following information about a selected project: Owner, Address, Balance, Goal, Raised, Deadline and Status
Selecting an ID will automaticall populate all the fields by calling the _getProject() function in the DAPP app.js.
The Project details button can also be used to retrieve updated information about the selected project. Not really required as the fields are updated automatically after doing a contribution for instance.