This repository contains a very simple registry smart contract which is used in the Drupal Ethereum module.
It allows the PHP Application (Drupal) to verify a visitors Blockchain address.
Summing up the flow
- Drupal creates a 32 bit hash
- The visitor "submits" this hash to the registry (this contract) using Metamask as a transaction signer
newUser(bytes32 drupalUserHash). Drupal will also save the Ethereum address the user claims to own. - Drupal can now call
validateUserByHash (bytes32 drupalUserHash). If the If the hash has been submitted with the users claimed address Drupal has a proof that the user actually owns the private key to sign this transaction.
You might easily turn this into a simple paywall contract.
Development with truffle
Requires truffle 4.X
Next to this contract there is a simple app to interact with the contract or modify it.
See quickstart below or https://truffleframework.com
contains a simple registry mapping a hash to a Ethereum Address A CMS like Drupal generates a hash for their users to approve an blockchain account.
The user is required to sign the "Registry transaction" with his blockchain key. The signing process can take place in web browsers or on mobile devices.
To sign a transaction in the browser you need a transaction signer like the Metamask Chrome/Firefox plug-in.
contracts/RegisterDrupal.sol
The Contract language is Solidity.
Solidity has a great tool you may use to develop and deploy out of the browser called REMIX. You will also need Metamask to do so.
Install NPM https://docs.npmjs.com/getting-started/installing-node
Install Truffle https://truffleframework.com/docs/getting_started/installation
npm install -g truffle
Install dependencies
npm install
Start truffle console (previously testrpc)
truffle develop
Truffle Develop started at https://localhost:9545/
Accounts:
(0) 0x627306090abab3a6e1400e9345bc60c78a8bef57
[ .... ]
Private Keys:
(0) c87509a1c067bbde78beb793e6fa76530b6382a4c0241e5e4a9ec0a0f44dc0d3
[ .... ]
This will start a local blockchain running at https://localhost:9545 Make sure to you set the Network in Metamask to this custom network address.
In truffle you can now build and deploy the contract:
truffle(develop)> compile
and migrate the Contracts. This will save the Contract meta information (artifacts) into build/contracts too.
truffle(develop)> migrate
Using network 'develop'.
Running migration: 1_initial_migration.js
Replacing Migrations...
... 0xd045bbc33fecb5352b5c01f9443d87df21287734abb499492e4dffb3be74bd62
Migrations: 0x8cdaf0cd259887258bc13a92c0a6da92698644c0
Saving successful migration to network...
... 0xd7bc86d31bee32fa3988f1c1eabce403a1b5d570340a3a9cdba53a472ee8c956
Saving artifacts...
Running migration: 2_deploy_contracts.js
Replacing RegisterDrupal...
... 0x992b104ddf616b5debce348d50f50193f76db94c00044f3c2c201bb51fffeece
RegisterDrupal: 0x345ca3e014aaf5dca488057592ee47305d9b3e10
Saving successful migration to network...
... 0xf36163615f41ef7ed8f4a8f192149a0bf633fe1a2398ce001bf44c43dc7bdda0
Saving artifacts...
Note:
- If your get an Error
Error: Attempting to run transaction which calls a contract function, but recipient address 0x8cdaf0cd259887258bc13a92c0a6da92698644c0 is not a contract addressyou might need to deletebuild/contracts/*.json - After restarting the development network you might get a nounce related error. Metamask tracks the TX on your account, if you reset the network you also need to reset the account in Metamask (settings Reset account).
Now keep the truffle console open (it's your local blockchain) and start the app
npm run dev
> [email protected] dev /Users/tho/htdocs/register_drupal_ethereum/register_drupal_update
> webpack-dev-server
Project is running at https://localhost:8081/
webpack output is served from /
Hash: f36739e2f122fef70704
Version: webpack 2.7.0
Time: 1466ms
Asset Size Chunks Chunk Names
app.js 1.67 MB 0 [emitted] [big] main
index.html 1.16 kB [emitted]
app.css 595 bytes [emitted]
images/drupal-8-logo.svg 1.24 kB [emitted]
chunk {0} app.js (main) 1.65 MB [entry] [rendered]
[71] ./app/javascripts/app.js 4.86 kB {0} [built]
[72] (webpack)-dev-server/client?https://localhost:8081 7.91 kB {0} [built]
[73] ./build/contracts/RegisterDrupal.json 51.3 kB {0} [built]
[109] ./~/loglevel/lib/loglevel.js 7.86 kB {0} [built]
[117] ./~/strip-ansi/index.js 161 bytes {0} [built]
[154] ./~/truffle-contract-schema/index.js 5.4 kB {0} [built]
[159] ./~/truffle-contract/index.js 2.64 kB {0} [built]
[193] ./~/url/url.js 23.3 kB {0} [built]
[194] ./~/url/util.js 314 bytes {0} [built]
[195] ./~/web3/index.js 193 bytes {0} [built]
[229] (webpack)-dev-server/client/overlay.js 3.67 kB {0} [built]
[230] (webpack)-dev-server/client/socket.js 1.08 kB {0} [built]
[231] (webpack)/hot nonrecursive ^\.\/log$ 160 bytes {0} [built]
[232] (webpack)/hot/emitter.js 77 bytes {0} [built]
[233] multi (webpack)-dev-server/client?https://localhost:8081 ./app/javascripts/app.js 40 bytes {0} [built]
+ 219 hidden modules
webpack: Compiled successfully.
This will start a local webserver at https://localhost:8081.