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Query Worker Tutorial

This tutorial is about using C8QL queries as API (aka Query Workers) in Macrometa GDN with low latencies across the globe.

Installation​

With Yarn or NPM

    yarn add jsc8
    (or)
    npm install jsc8

If you want to use the SDK outside of the current directory, you can also install it globally using the `--global` flag:

    npm install --global jsc8

From source,

    git clone https://github.com/macrometacorp/jsc8.git
    cd jsC8
    npm install
    npm run dist

Code Sample​

const jsc8 = require("jsc8");

const globalUrl = "https://play.paas.macrometa.io";

/*
// Create auth instance with token
const client = new jsc8({
    url: gdnUrl,
    token: "XXXX",
    fabricName: '_system'
});

// ----- OR -----
// Create an auth instance with an API key
const client = new jsc8({
    url: gdnUrl,
    apiKey: "XXXX",
    fabricName: '_system'
});

// ----- OR -----
// Create an auth instance using an email and password
const client = new jsc8(gdnUrl);
await client.login("nemo@nautilus.com", "xxxxx");
*/

// Connect to GDN
const client = new jsc8({ url: globalUrl, apiKey: "XXXXX", fabricName: "_system" });

// Variables
const collectionName = "address";

// Variables - Query Workers
const parameter = { firstname: "", lastname: "", email: "", zipcode: "" };

const insertDataValue = {
  query: {
    name: "insertRecord",
    value: `INSERT {'firstname':@firstname, 'lastname':@lastname, 'email':@email, 'zipcode':@zipcode, '_key': 'abc'} 
      IN ${collectionName}`,
    parameter
  }
};

const getDataValue = {
  query: {
    name: "getRecords",
    value: `FOR doc IN ${collectionName} RETURN doc`
  }
};

const updateDataValue = {
  query: {
    name: "updateRecord",
    value: `UPDATE 'abc' WITH { "lastname": "cena" } IN ${collectionName}`
  }
};

const deleteDataValue = {
  query: {
    name: "deleteRecord",
    value: `REMOVE 'abc' IN ${collectionName}`
  }
};

const getCountValue = {
  query: {
    name: "countRecords",
    value: `RETURN COUNT(FOR doc IN ${collectionName} RETURN 1)`
  }
};

// Step 1: Open connection to GDN. You will be routed to the closest region.
console.log(`\n1. Connecting to federation: ${globalUrl}`);

async function createCollection () {
  console.log("\n2. Creating collection.");

  try {
    console.log(`Creating the collection ${collectionName}...`);
    const existsColl = await client.hasCollection(collectionName);
    if (existsColl === false) {
      await client.createCollection(collectionName);
      console.log(`Collection ${collectionName} has been created successfully.`);
    } else {
      console.log(`Collection ${collectionName} already exists.`);
    }
  } catch (e) {
    console.log("Collection creation did not succeed due to " + e);
  }
}

// This function creates the needed collection or displays a message if it already exists.
async function insertQueryWorker (nameToCheck, value, parameterToCheck) {
  let queryAlreadyExists = false;
  const queryList = await client.getRestqls();
  try {
    for (let i = 0; i < queryList.result.length; i++) {
      if (queryList.result[i].name === nameToCheck) {
        queryAlreadyExists = true;
        break;
      }
    }

    if (queryAlreadyExists) {
      console.log(`Query worker ${nameToCheck} already exists.`);
    } else {
      await client.createRestql(nameToCheck, value, parameterToCheck);
      console.log(`Query worker ${nameToCheck} created successfully.`);
    }
  } catch (e) {
    console.log("Could not check the list of query workers due to " + e);
  }
}

async function createRestQL () {
  console.log("\n3. Creating query workers.");

  try {
    await insertQueryWorker(insertDataValue.query.name.toString(), insertDataValue.query.value.toString(), insertDataValue.query.parameter);
    await insertQueryWorker(getDataValue.query.name.toString(), getDataValue.query.value.toString(), {});
    await insertQueryWorker(updateDataValue.query.name.toString(), updateDataValue.query.value.toString(), {});
    await insertQueryWorker(deleteDataValue.query.name.toString(), deleteDataValue.query.value.toString(), {});
    await insertQueryWorker(getCountValue.query.name.toString(), getCountValue.query.value.toString(), {});

    console.log("All query workers are now in the system.");
  } catch (e) {
    console.log("Query workers could not be created due to " + e);
  }
}

async function executeRestQL () {
  console.log("\n4. Running query workers");
  console.log("\n a. Insert data");

  let resp = await client.executeRestql(insertDataValue.query.name.toString(), {
    firstname: "john",
    lastname: "doe",
    email: "john.doe@macrometa.io",
    zipcode: "511037"
  }).catch(e => console.log(console.error(e)));
  console.log(resp.result);

  console.log("\n b. Get data");
  resp = await client.executeRestql(getDataValue.query.name.toString(), {});
  console.log(resp.result);

  console.log("\n c. Update data");
  resp = await client.executeRestql(updateDataValue.query.name.toString(), {});
  console.log(resp.result);

  console.log("\n d. Get data");
  resp = await client.executeRestql(getDataValue.query.name.toString(), {});
  console.log(resp.result);

  console.log("\n e. Count records");
  resp = await client.executeRestql(getCountValue.query.name.toString(), {});
  console.log(resp.result);

  console.log("\n f. Delete record");
  resp = await client.executeRestql(deleteDataValue.query.name.toString(), {});
  console.log(resp.result);
}

async function deleteRestQL () {
  console.log("\n5a. Deleting query workers.");

  try {
    await client.deleteRestql(insertDataValue.query.name.toString());
    await client.deleteRestql(getDataValue.query.name.toString());
    await client.deleteRestql(updateDataValue.query.name.toString());
    await client.deleteRestql(getCountValue.query.name.toString());
    await client.deleteRestql(deleteDataValue.query.name.toString());

    console.log("All query workers deleted.");
  } catch (e) {
    console.log("Could not delete query workers due to " + e);
  }
}

async function deleteCollection () {
  console.log("\n5b. Deleting the collection.");

  try {
    console.log(`Removing the collection ${collectionName}...`);
    const existsColl = await client.hasCollection(collectionName);
    if (existsColl === false) {
      console.log(`Can't remove non-existent collection: ${collectionName}.`);
    } else {
      await client.deleteCollection(collectionName);
      console.log(`Collection ${collectionName} has been deleted successfully.`);
    }
  } catch (e) {
    console.log("Collection creation did not succeed due to " + e);
  }
}

(async function () {
  await createCollection();
  await createRestQL();
  await executeRestQL();
  await deleteRestQL();
  await deleteCollection();
})();