Complete the example

Let's add the remaining parts of our client to test different functions.

We start by defining the rest of our Book Review and Transaction (Tx) model:

type BookReview = {
  book: Book;
  reviewer_name: string;
};

type TxOp = {
  op_name: string;
  op_args: any[];
};

type TxBody = {
  tx_rid: Buffer;
  ops: TxOp[];
  signers: Buffer[];
};

type Tx = {
  tx_body: TxBody;
  signatures: Buffer[];
};

We define functions to query for entities and some helper functions to read input from user:

const rl = readline.createInterface({
  input: process.stdin,
  output: process.stdout,
});

function getInput(query: string): Promise<string> {
  return new Promise((resolve) => {
    rl.question(query, (answer) => {
      resolve(answer);
    });
  });
}

const getReviewsForBook = async (isbn: string) => {
  const bookList = await client.query<BookReview[]>("get_all_reviews_for_book", { isbn: isbn });
  console.log("Book review list\n", bookList);
};

const getAllTransactions = async () => {
  await client.query<Tx[]>("get_transactions", {}).then((transactions) => {
    transactions.forEach((tx) => {
      console.log("TxRID:", tx.tx_body.tx_rid.toString("hex"));
      tx.tx_body.ops.forEach((op) => {
        console.log("OpName:", op.op_name);
        console.log("OpArgs:", op.op_args);
      });
    });
  });

  const transactions = (await client.query("get_transactions", {})) as Tx[];
  transactions.forEach((tx) => {
    console.log("TxRID:", tx.tx_body.tx_rid.toString("hex"));
    tx.tx_body.ops.forEach((op) => {
      console.log("OpName:", op.op_name);
      console.log("OpArgs:", op.op_args);
    });
  });
};

and finally our complete main function where we in this code example have added some more functions to show queries and transactions:

async function main() {
  client = await createClient({
    nodeUrlPool: "http://localhost:7740",
    blockchainRid: blockchainRID,
  });

  console.log("Creating a new book transactions");
  await client.signAndSendUniqueTransaction(
    { name: "create_book", args: ["ISBN1", "Chromia 101", "John Doe"] },
    bookKeeperSignatureProvider
  );
  await getInput("Transaction comitted!\npress any key to continue...");

  console.log("Let's fetch and view all books currently in the node");
  await getAllBooks();
  await getInput("Press any key to continue...");

  console.log("We can now add a second book");
  await client.signAndSendUniqueTransaction(
    { name: "create_book", args: ["ISBN2", "Rell 101", "Jane Doe"] },
    bookKeeperSignatureProvider
  );
  await getInput("Transaction comitted, press any key to continue...");

  console.log("Let's fetch and view all books currently in the node");
  await getAllBooks();
  await getInput("Press any key to continue...");

  console.log("We can now add two reviews for the book with ISBN = ISBN2");

  await client.signAndSendUniqueTransaction(
    {
      name: "create_book_review",
      args: ["ISBN2", "Bob Doe", "This is a great book!", 5],
    },
    bookKeeperSignatureProvider
  );
  await client.signAndSendUniqueTransaction(
    {
      name: "create_book_review",
      args: ["ISBN2", "Charlie Doe", "It was ok!", 3],
    },
    bookKeeperSignatureProvider
  );
  await getInput("Transaction comitted, press any key to continue...");

  console.log("Let's fetch and view all books currently in the node");
  await getReviewsForBook("ISBN2");
  await getInput("Press any key to continue...");

  console.log("Now lets look at all transaction that have been commited to the blockchain");
  await getAllTransactions();
  await getInput("Press any key to continue...");
}

Now, we have a fully functional example to showcase how straightforward it is to implement a front-end client using Chromia and Postchain-client.