For up-to-date product documentation, see the IBM MobileFirst Foundation Developer Center.

MobileFirst JavaScript adapters

With IBM MobileFirst™ Platform Foundation, we can create, test, and deploy adapters that are written in JavaScript.

For more general information about MobileFirst adapters, see Adapters overview.

Benefits of MobileFirst JavaScript adapters

In addition to benefits that adapters provide in general, JavaScript adapters also provide these:

• Fast development: Adapters are developed in JavaScript and XSL. Developers employ flexible and powerful server-side JavaScript to produce succinct and readable code for integrating with back-end applications and processing data. Developers can also use XSL to transform hierarchical back-end data to JSON.
• REST Interface: With the REST interface, we can benefit from the OAuth 2.0 security framework. For more information, see Client access to adapters.

JavaScript adapter types

IBM MobileFirst Platform Foundation V8.0.0 supports HTTP and SQL adapters:

• With a HTTP adapter, we can send GET or POST HTTP requests and retrieve data from the response headers and body. HTTP adapters work with RESTful and SOAP-based services, and can read structured HTTP sources such as RSS feeds.
• With an SQL adapter, we can communicate with any SQL data source. We can use plain SQL queries or stored procedures.

The JavaScript adapter framework

The adapter framework mediates between the mobile apps and the enterprise. A typical flow is depicted in the following diagram.

• The connectivity and auto-conversions are facilities that are provided with IBM MobileFirst Platform Foundation.
• The back-end application, JavaScript code and XSLT components in the MobileFirst Server are supplied by the adapter or app developer.

Figure 1. The JavaScript adapter framework

• An adapter provides a set of services, called procedures. Mobile apps invoke procedures by issuing Ajax requests.
• The procedure retrieves information from the back-end application.
• The back-end application then returns data in some format:
  • If this format is JSON, the MobileFirst Server keeps the data intact.
  • If this format is not JSON, the MobileFirst Server automatically converts it to JSON. Alternatively, we can provide an XSL transformation (XSLT) to convert the data to JSON. In this case, the returned content type from the back end must be XML. Then, we can use an XSLT to filter the data.

• The JavaScript implementation of the procedure receives the JSON data, performs any additional processing, and returns it to the calling app.

Note:

• Writing an adapter that pulls large amounts of data and transfers it to the client application is discouraged because the data must be processed twice: once at the adapter and once again at the client application.
• HTTP POST requests are used for client-server communications between the MobileFirst application and the MobileFirst Server. Parameters must be supplied in a plain text or numeric format. To transfer images (or any other type of file data), they must first be encoded in Base64 format.

• The JavaScript adapter-descriptor file
  Learn about the function and structure of the Java adapter-descriptor file.
• Work with JavaScript adapters
  Learn how to develop, build, deploy, push, and pull Java adapters.
• Develop JavaScript adapter code
  Learn about implementing JavaScript adapters.

Parent topic: Develop the server side of a MobileFirst application