The sample contract serves as a demonstration of general QVM logic.
It is capable of:
registering users into the database
storing the last registered user's name in the database
echoing the previous user's name to STDOUT
incrementing the total registered user count
storing above counter in the database
Sample code
function contract(args: string[]) {
// THIS SAMPLE ONLY SUPPORTS THE "register" FUNCTION
if (args && args.length === 2 && args[0] === "register") {
// GET THE CURRENT USER'S NAME OR DEFAULT TO "unknown" IF THIS IS THE FIRST CALL
const previous_name: string = process.env.DB_USER_CURRENT || "unknown";
// GET THE TOTAL USER COUNT
const total_user_count: number = parseInt(process.env.DB_TOTALUSERS || "0");
// WRITE PREVIOUS USER NAME TO STDOUT
process.stdout.write(`OUT=prevname: ${previous_name}\n`);
// UPDATE CURRENT USER NAME BY WRITING IT TO DB
process.stdout.write(`DBW=USER_CURRENT=${args[1]}\n`);
// STORE USER NAME UNDER A STORAGE SLOT FOR PERSISTENCE (CURRENT GETS OVERWRITTEN ON EACH CALL)
process.stdout.write(`DBW=USER_${total_user_count}=${args[1]}\n`);
// INCREMENT THE TOTAL USER COUNT
process.stdout.write(`DBW=TOTALUSERS=${(total_user_count + 1)}\n`);
process.exit(0);
}
if (args.length >= 1) {
process.stderr.write(`Wrong CMD: ${args[0]}\n`);
process.exit(1);
}
process.stderr.write("Wrong args!\n");
process.exit(1);
}
contract(process.argv.slice(2));
Save the contract
Open a text editor and save above sample contract as main.ts file.
