Spring 5.0 Microservices - Second Edition

Use of API gateways in microservices

With the advancement of client-side JavaScript frameworks, such as Angular JS, the server is expected to expose RESTful services. This could lead to two issues. The first issue is the mismatch in contract expectations. The second issue is the multiple calls to the server to render a page.

We start with the contract mismatch case. For example, GetCustomer may return a JSON with many fields, as follows:

    Customer {      Name:      Address:      Contact :    }

In the preceding example, Name, Address, and Contact are nested JSON objects. But a mobile client may expect only basic information, such as the first name and last name. In the SOA world, an ESB or mobile middleware did this job of transformation of data for the client. ...