Use Azure Table Storage

This How to is based on the Medium article by Andrew Varnon

The implementation is done using a Smart Collection and a CRUD service that will wrap the Azure Table Storage API.

The Table Storage Definition

You can use the new Azure Data Explorer to create and populate a Table Storage in your Azure Storage account.

In our example, we are going to use the Table Customers with the fields:

• Id: PartitionKey + RowKey

• Timestamp (updated at)

• Email as String

• FirstName as String

• LastName as String

Install Azure data-tables package

npm install @azure/data-tables --save

Smart Collection definition

const { collection } = require('forest-express-sequelize');

collection('customers', {
  fields: [{
    field: 'id',
    type: 'String',
    get: (customer) => `${customer.partitionKey}|${customer.rowKey}`,
  }, {
    field: 'partitionKey',
    type: 'String',
  }, {
    field: 'rowKey',
    type: 'String',
  }, {
    field: 'timestamp',
    type: 'Date',
  }, {
    field: 'Email',
    type: 'String',
  }, {
  field: 'LastName',
  type: 'String',
  }, {
    field: 'FirstName',
    type: 'String',
  }, ],
});

The Azure Data Tables Service Wrapper

const { TableClient } = require('@azure/data-tables');

const getClient = (tableName) => {
  const client = TableClient.fromConnectionString(
    process.env.AZURE_STORAGE_CONNECTION_STRING,
    tableName);
  return client;
}

const azureTableStorageService = {
  deleteEntityAsync: async (tableName, partitionKey, rowKey) => {
    const client = getClient(tableName);
    await client.deleteEntity(partitionKey, rowKey);
  },

  getEntityAsync: async (tableName, partitionKey, rowKey) => {
    const client = getClient(tableName);
    return client.getEntity(partitionKey, rowKey);
  },

  listEntitiesAsync: async (tableName, options) => {
    const client = getClient(tableName);
    var azureResponse = await client.listEntities();

    let iterator = await azureResponse.byPage({maxPageSize: options.pageSize});

    for (let i = 1; i < options.pageNumber; i++) iterator.next(); // Skip pages

    let entities = await iterator.next();
    let records = entities.value.filter(entity => entity.etag);

    // Load an extra page if we need to allow (Next Page)
    const entitiesNextPage = await iterator.next();
    let nbNextPage = 0;
    if (entitiesNextPage && entitiesNextPage.value) {
      nbNextPage = entitiesNextPage.value.filter(entity => entity.etag).length;
    }

    // Azure Data Tables does not provide a row count. 
    // We just inform the user there is a new page with at least x items
    const minimumRowEstimated = (options.pageNumber-1) * options.pageSize + records.length + nbNextPage;

    return {records, count: minimumRowEstimated};
  },

  createEntityAsync: async (tableName, entity) => {
    const client = getClient(tableName);
    delete entity['__meta__'];
    await client.createEntity(entity);
    return client.getEntity(entity.partitionKey, entity.rowKey);
  },

  udpateEntityAsync: async (tableName, entity) => {
    const client = getClient(tableName);
    await client.updateEntity(entity, "Replace");
    return client.getEntity(entity.partitionKey, entity.rowKey);
  },

};

module.exports = azureTableStorageService;

Routes definition

const express = require('express');
const { PermissionMiddlewareCreator, RecordCreator, RecordUpdater } = require('forest-express');
const { RecordSerializer } = require('forest-express');

const router = express.Router();

const COLLECTION_NAME = 'customers';
const permissionMiddlewareCreator = new PermissionMiddlewareCreator(COLLECTION_NAME);
const recordSerializer = new RecordSerializer({ name: COLLECTION_NAME });

const azureTableStorageService = require("../services/azure-table-storage-service");

// Get a list of Customers
router.get(`/${COLLECTION_NAME}`, permissionMiddlewareCreator.list(), async (request, response, next) => {
  const pageSize = parseInt(request.query.page.size) || 15;
  const pageNumber = parseInt(request.query.page.number);

  azureTableStorageService.listEntitiesAsync(COLLECTION_NAME, {pageSize, pageNumber})
  .then( async ({records, count}) => {
    const recordsSerialized = await recordSerializer.serialize(records);
    response.send({ ...recordsSerialized, meta: { count }});
  })
  .catch ( (e) => {
    console.error(e);
    next(e);

  });
});

// Get a Customer
router.get(`/${COLLECTION_NAME}/:recordId`, permissionMiddlewareCreator.details(), async (request, response, next) => {
  const parts = request.params.recordId.split('|');
  azureTableStorageService.getEntityAsync(COLLECTION_NAME, parts[0], parts[1])
  .then( (record) => recordSerializer.serialize(record))
  .then( (recordSerialized) => response.send(recordSerialized))
  .catch ( (e) => {
    console.error(e);
    next(e);  
  });
});

// Create a Customer
router.post(`/${COLLECTION_NAME}`, permissionMiddlewareCreator.create(), async (request, response, next) => {      
  const recordCreator = new RecordCreator({name: COLLECTION_NAME}, request.user, request.query);
  recordCreator.deserialize(request.body)
  .then( (recordToCreate) => {
    return azureTableStorageService.createEntityAsync(COLLECTION_NAME, recordToCreate);
  })
  .then((record) => recordSerializer.serialize(record))
  .then((recordSerialized) => response.send(recordSerialized))
  .catch ( (e) => {
    console.error(e);
    next(e);
  });
});

// Update a Customer
router.put(`/${COLLECTION_NAME}/:recordId`, permissionMiddlewareCreator.update(), async (request, response, next) => {
  const parts = request.params.recordId.split('|');
  const recordUpdater = new RecordUpdater({name: COLLECTION_NAME}, request.user, request.query);
  recordUpdater.deserialize(request.body)
  .then( (recordToUpdate) => {
    recordToUpdate.partitionKey = parts[0];
    recordToUpdate.rowKey = parts[1];
    return azureTableStorageService.udpateEntityAsync(COLLECTION_NAME, recordToUpdate);
  })
  .then( (record) => recordSerializer.serialize(record) )
  .then( (recordSerialized) => response.send(recordSerialized) )
  .catch ( (e) => {
    console.error(e);
    next(e);
  });

});

// Delete a list of Customers
router.delete(`/${COLLECTION_NAME}`, permissionMiddlewareCreator.delete(), async (request, response, next) => {
  try {
    for (const key of request.body.data.attributes.ids) {
      const parts = key.split('|');
      await azureTableStorageService.deleteEntityAsync(COLLECTION_NAME, parts[0], parts[1]);
    }
    response.status(204).send()
  } catch (e) {
    console.error(e);
    next(e);
  }
});

module.exports = router;

Result