API Proxy for Ex Libris Cloud Apps

This Lambda function provides an API proxy for use by Ex Libris Cloud Apps to access data in other institutions (for example, in a corsortial topology). The API can be hosted on AWS infrastructure

• CORS support
• Validation of Cloud App authentication token
• Ability to limit allowed Cloud Apps and institutions (see Configuration below)
• Retrieval of API key from an AWS Secret Manager secret based on the institution code pased in an X-For-InstCode header
• Proxy of API request and response to Alma

To deploy to AWS, follow the steps below. (These instructions assume you have an AWS account, and that the AWS CLI is installed and configured.

1. Clone repository

$ git clone https://github.com/jweisman/exl-cloudapp-api-proxy

2. Install dependencies

$ cd exl-cloudapp-api-proxy/dependencies/nodejs/ && npm install && cd ../../

3. Create a .npmrc file with the following content:

s3_bucket_name = BUCKET_NAME # Name of bucket in your AWS account to upload the assets to
region = eu-central-1 # Region to deploy to
cloud_formation_stack_name = ExlApiProxy # Stack name
allowed_apps =  # Optional list of allowed apps
allowed_inst_codes =  # Optional list of allowed institution codes

4. Run the following to deploy the CloudFormation template. The output will include the URL of the proxy and the identifier of the API keys secret.

$ npm run deploy

5. Update the secret by creating a JSON file with the institution codes and API keys as name/value pairs, and then running the following command, for example:

$ echo '{"01_MYINST":"l7xx......"}' > apikeys.json
$ npm run update-keys --file=apikeys.json

The Angular component in this Gist can be added to a Cloud App and used to test the proxy. Don't forget to add the proxy URL to the contentSecurity section of the manifest.

The following optional environment variables are supported in the Lambda function. They can also be set in the .npmrc file as described above.

• CLOUDAPP_AUTHORIZER_ALLOWED_APPS: Comma separated list of allowed Cloud App IDs (Github username/repository name, e.g. ExLibrisGroup/alma-hathitrust-availability)
• CLOUDAPP_AUTHORIZER_ALLOWED_INST_CODES: Comma separated list of allowed institution codes (e.g. 01MYUNI_INST1, 01MYUNI_INST2)
• API_KEYS_SECRET_NAME: The name of the Secret Manager secret which stores API keys in name/value pairs