Upload and Download / Blob Adapters

  Amazon Simple Storage Service (Amazon S3)

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Upload and Download / Blob AdaptersPrint||
Amazon Simple Storage Service (Amazon S3)

Amazon Simple Storage Service (Amazon S3) is a cloud-based data storage solution. Let’s add fields to the Suppliers table in the Northwind database in order to store company logos. The picture file name, size, and content type will be saved in the database, while the files will be uploaded to S3.

Setting Up S3

Navigate to http://aws.amazon.com/s3 and log in to your account. If you do not have an active account for Amazon S3, sign up for AWS Free Usage Tier.

When logged into the AWS Management Console, select S3 under Storage & Content Delivery section. Click on Create Bucket.

Creating a bucket in Amazon S3.

Enter a bucket name and press Create.

Naming and creating the bucket.

When complete, click on the account name in the top right corner and select Security Credentials. Scroll down to Access Keys section. If necessary, create a new access key. Click on Show under Secret Access Key and save both the Secret Access Key and Access Key ID for later use.

Getting the access key for Amazon S3.

Adding Utility Fields to the Database

Start SQL Server Management Studio. In the Object Explorer, right-click on Databases / Northwind / Tables / dbo.Suppliers, and press Design.

Designing the Suppliers table.

Add the following columns:

Column Name Data Type Allow Nulls
LogoFileName nvarchar(250) yes
LogoLength int yes
LogoContentType nvarchar(50) yes

Save the changes. Switch to the generator and click on the project name. Select Refresh, check the box next to Suppliers controller, and proceed to refresh the web app.

Refreshing the Suppliers controller.

Configuring BLOB Field

Start the Project Designer. In the Project Explorer, switch to the Controllers tab. Right-click on Suppliers / Fields node, and press New Field.

Creating a new field for Suppliers controller.

Assign the following properties:

Property Value
Name Logo
Type Byte[]
Allow Null Values yes
Value is retrieved on demand yes
Source Fields SupplierID
On Demand Handler LogoBlobHandler
On Demand Style Thumbnail
Label Logo

Save the field. Drag the new field node and drop it onto Suppliers/ Views / editForm1 to instantiate the field as a data field in the editForm1 view.

Adding a data field of Logo to view 'editForm1'.     Logo data field added.

Drag the field onto view grid1 to display the picture in the list of products.

Next, double-click on the Suppliers controller node. Enter the following in BLOB Adapter Configuration.

BLOB Adapter Configuration

Field: Logo
Storage-System: S3
Secret-Access-Key: lNFaASDFyosrjY3j77ASDFCUTHj408Pgz5yoCci
Bucket: northwind
Path-Template: {SupplierID}-{LogoFileName}

Note that the values above are not functional. Replace the highlighted parts with your own settings.

Make sure to save the controller.

Viewing the Results

On the toolbar, press Browse. Navigate to the Suppliers page and start editing a record. The new Logo field will accept file uploads. Click on the link and upload a file. The bar at the top of the screen will show a confirmation of upload and a thumbnail of the picture will be displayed. The File Name, Length, and Content Type utility fields will be updated accordingly.

Image uploaded to Amazon S3 and thumbnail is displayed.

The files can be seen in AWS Management Console.

Files uploaded to Amazon S3.

To upload files larger than 4 MB, you will need to increase the application upload size limit.