Uses Lambda@Edge to process the web request of a user and provide a 301 response redirecting the user to a new location. This functionality is helpful for public web hosting, specifically for advertising campaigns that need to be tracked and redirect users to a sign-up page.
This solution is a Lambda@Edge function that checks the URI the user is requesting on the CloudFront distribution, checks an internal JSON object for a redirect, and then responds to the requestor with a 301 response to the new document.
This solution requires:
- An empty S3 web hosting bucket
- An S3 web hosting bucket to host web assets for a landing zone
- A Lambda@Edge function, written in Node.js 6.10
- A CloudFront distribution in front of the empty bucket
- An optional S3 bucket for CloudFront logging
This version has been written to only use Edge technologies. Data is included in a JSON document variable to reduce the need for any regional network calls.
- Create the S3 Buckets
This solution requires 2 S3 buckets, as described above. If you have Python and
the Python SDK installed, you can simply run the command:
python setupbuckets.py <webbucket> <emptybucket>
This script will create both buckets, turn on encryption, turn on web hosting, and also copy some sample public files to the webbucket.
You can also create these buckets manually. If you do, make sure that they have web hosting turned on. Also, make sure to mark the files in your webbucket as public so they can be served to the requestor.
As an optional step, you can also create a bucket to store your CloudFront logs in. This bucket will be used to provide logging for the initial requests, which is important for the use case value proposition.
- Create an IAM role for Lambda@Edge Create a new role with trust relationships for: a. lambda.amazonaws.com b. edgelambda.amazonaws.com
Attach the policy listed below: a. AWSLambdaExecute
- Create the Lambda@Edge function Create a new Lambda function from scratch, using Node.js 6.10 as the runtime, and use the role you created in step 2 for execution. Paste in the code from rewriteurledge.js.
a. Data for your web site host is provided in the config section of the JSON document variable. The values are: i. host - the host address of the website you want to redirect users to ii. error_page - the error page to use on your host iii. campaign_over_page - page to show when a campaign is expired or not active.
b. Data for the redirects is provided in the rules section of the JSON document variable. The values are: i. object name - the URI to redirect from ii. rewrite - the URI to redirect to on your host iii. startdate - the starting date of the campaign (when it should start redirecting) iv. enddate - the ending date of the campaign (when it should stop redirecting)
Please see step 5 for information about the use cases.
You can also create testing events for the Lambda function, which are included in the repository as .json files. Test the function to make sure that it works.
You must publish this function before the final step. Click on Actions -> Publish
New Version and validate the Lambda function was published. You should see an ARN
at the top of the page that looks like: arn:aws:lambda:us-east-1:1234567890:function:URLrewrite2:22
Copy the ARN plus the version number (:22, in this case), as you will need it for
the CloudFront distribution. CloudFront cannot use $latest as a version at this time.
- Create the CloudFront Distribution Create a new Web CloudFront Distribution. The origin name is your empty bucket from step 1. Values that you should change are: a. Restrict Bucket Access - Yes b. Lambda Function Association -> Event Type - Viewer Request c. Lambda Function Association -> Lambda Function ARN - your full ARN from step 3
You can enable logging, if you choose, by using the following settings: a. Logging - On b. Bucket for Logs - your logging bucket from step 1 c. Log Prefix - choose a prefix to use for this distribution
Once you set these values, click on Create Distribution. Once your distribution is complete, you will have a URL rewriter, using HTTP 301, functioning at the edge.
- Test Cases / Test Data The test cases that are included in the JSON document variable are date dependent and all testing will result in an error or campaign over response as of 1/12/2018.
You can test the distribution with the following tests, no matter what the current date is: a. /test1 - will either redirect to /testpage1.html or /campaignover.html depending on the date. b. /test4 - will redirect to /error.html
If you change the dates in the Lambda function after you have published it, you will need to republish the function and update the CloudFront Distribution to point to the new version of the Lambda function.