Connections

Overview

Some third party APIs are exposed as multiple instances or environments. For example, in addition to the regular "production" environment, they may expose a "sandbox" environment. The API contract is exactly the same, and the authorization process is exactly the same, but a part of the request (often, the hostname) is different. It can be useful to allow access to all of the environments (called "Connections" in this documentation) through the same ShipEngine Connect App, since most of the code should be exactly the same.

In order to support multiple environments, your AuthProcess definition must include a connections section. It requires two attributes: connection_names and default_connection_name.

The default_connection_name must define the connection to use when one is not specified by the end user. In some situations, the end user will not have a choice, so the connection they use is driven by the default_connection_name.

The value of connection_names is an object keyed by the names (strings) of the available connections (ex: "production" and "sandbox"). The value of each entry is a JSON object containing all of the configuration that needs to vary by connection. Each configuration object should have the same shape for each connection, but with different values. For example, if you need to vary the authorization URL by connection, each connection object might have an authorization_url entry with a different value. The JSON object can take any shape and be as deep as you need, as long as you can reference the values you need to extract using JSONPath.

The data in the connection_names section is available to the AuthProcess definition via the connection_name: template resolver. It can access individual parts of the configuration object via a JSONPath query. This allows you to vary the OAuth process based on the environment.

The module itself can also vary its logic based on the connection. For apps that define connection_names, each incoming request to their functions will include a request.auth.connection_name property indicating which environment to use for the given request.

Example

Consider this example (partial) AuthProcess definition:

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authorization: {
  url_template: '{connection_name:$.url}/oauth2/auth',
},

// ... elided irrelevant sections

connections: {
  default_connection_name: 'production',
  connection_names: {
    sandbox: {
      url: https://api-sandbox.example.com
    },
    production: {
      url: https://api.example.com
    },
  }
}

For this 3rd party, the URL that will be used during the authorization phase needs to be different, depending on if you are accessing their production environment, or their sandbox environment. Therefore, the url_template makes use of the connection_name resolver to substitute in a value from the connections section. The connection_name resolver will automatically scope to the connection_names section based on the connection chosen for the current process. It will then apply the $.url JSONPath to pull out the value it needs. So if a user starts the OAuth flow and indicates they want the sandbox environment, the {connection_name:$.url} template value will resolve to https://api-sandbox.example.com.

After the connection is established and a request is made to the app's functions, the app can vary its logic based on the connection:

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const baseUrl = (request.auth.connection_name==='sandbox') ?
  "https://api-sandbox.example.com" :
  "https://sandbox.example.com";