This example Sinatra application implements a basic photo gallery to demonstrate how file uploading and processing works.
Rather than storing the files in the public directory, this application integrates with Amazon's Simple Storage Service (aka Amazon S3). This application will need information about your Amazon Web Services (AWS) account in order to upload files successfully. See below for how to do this.
We use the MiniMagick gem to resize, crop, etc. our uploaded photos which uses the ImageMagick program to do its work. That means we need to make sure we have ImageMagick installed.
To install ImageMagick on Cloud9, run
$ sudo apt-get install ImageMagick
To install ImageMagick on OS X using homebrew, run
$ brew install ImageMagick
Make sure you're in the public-file-upload directory. Once there, run the following two commands to configure your application correctly:
$ bundle install --without production
$ rake setup:dotenv
Before we can run our application, we need to set up our Amazon Web Services (aka AWS) account. AWS encompasses dozens of Amazon "cloud services," including Amazon's Simple Storage Service (aka S3), which is where we'll be sending our user-uploaded images. This is necessary on services like Heroku which don't allow us to save user-uploaded files directly in our web application's public directory.
To use Amazon's Simple Storage Service (aka S3), you'll first need to create an AWS account.
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Sign up for Amazon AWS.
When you've successfully signed up, you'll see what's called the AWS Management Console — a big list of Amazon services you can sign up for.
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Once you've signed up, we need to create what Amazon calls Access Keys in order to interact with AWS programmatically.
To do this, click on your account name in the upper right-hand corner. A dropdown should appear which contains a link to the Security Credentials page.
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On the security credentials page, click the Access Keys section. You should see a button labeled Create New Access Key. When you click this button you should see a small popup that contains two pieces of information: an Access Key ID and a Secret Access Key.
These act as a kind of username/password combination for your AWS account, so don't publish them anywhere public!
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Inside the
.envfile, edit the lines that readAWS_ACCESS_KEY_ID="fill-me-in" AWS_SECRET_ACCESS_KEY="fill-me-in"and replace
"fill-me-in"with the Access Key ID and Secret Access Key that Amazon gave you. Here are two example values, so you can see what they look like.# These are just examples and won't actually work. Use the values # that Amazon gave you. AWS_ACCESS_KEY_ID="AKIAIBU4G7ZPNSEXSVFQ" AWS_SECRET_ACCESS_KEY="Pg+j/VKlpSENGyEOidEKHHQ3Ox9Nxs0T35VcyCAK"
This Access Key ID and Secret Access Key will allow us to interact with any Amazon web service, including S3.
Now that we have an AWS account, we need to enable and configure Amazon's Simple Storage Service (aka S3) for our account.
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Navigate to the Amazon S3 section in the Management Console.
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Create a new bucket by clicking the Create Bucket button.
Note: This name has to be unique across all bucket names on S3, so pick something likely to be unique, e.g.,
myname-s3-upload-demo. -
In your
.envfile, replace
```text
AWS_S3_BUCKET_NAME="fill-me-in"
```
with the actual name of your S3 bucket. For exampe,
```text
# This is just an example - use your own bucket name.
AWS_S3_BUCKET_NAME="myname-s3-upload-demo"
```
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By default, any file you upload to S3 will be available at https://my-bucket-name.s3.amazonaws.com/example-file.jpg.
We'll need this host name — called the asset host — so that we can link to the correct image. The
.envfile is set up to work this way out of the box so long as you correctly set theAWS_S3_BUCKET_NAMEenvironmenet variable.
If you're using Cloud9, run the application with
$ ruby app.rb -p $PORT -o $IP
If you're on your own computer, run the application with
$ ruby app.rb
If everything runs successfully, you should be able to visit http://localhost:4567 and see the web application.