Step 10: Descriptor for Applications

All application-specific configuration settings will now further be put in a separate descriptor file called manifest.json. This clearly separates the application coding from the configuration settings and makes our app even more flexible. For example, all SAP Fiori applications are realized as components and come with a descriptor file in order to be hosted in the SAP Fiori launchpad.

The SAP Fiori launchpad acts as an application container and instantiates the app without having a local HTML file for the bootstrap. Instead, the descriptor file will be parsed and the component is loaded into the current HTML page. This allows several apps to be displayed in the same context. Each app can define local settings, such as language properties, supported devices, and more. And we can also use the descriptor file to load additional resources and instantiate models like our i18n resource bundle.

Preview

Figure 1: An input field and a description displaying the value of the input field (No visual changes to last step)

Coding

You can view and download all files in the Explored app in the Demo Kit under Walkthrough - Step 10.

Caution

Automatic model instantiation is only available as of SAPUI5 version 1.30. If you are using an older version, you can manually instantiate the resource bundle and other models of the app in the init method of the Component.js file as we did in Step 9: Component Configuration.

webapp/manifest.json (New)

{
  "_version": "1.1.0",
  "sap.app": {
	"_version": "1.1.0",
	"id": "sap.ui.demo.wt",
	"type": "application",
	"i18n": "i18n/i18n.properties",
	"title": "{{appTitle}}",
	"description": "{{appDescription}}",
	"applicationVersion": {
	  "version": "1.0.0"
	}
  },
  "sap.ui": {
	"_version": "1.1.0",
	"technology": "UI5",
	"deviceTypes": {
	  "desktop": true,
	  "tablet": true,
	  "phone": true
	},
	"supportedThemes": [
	  "sap_bluecrystal"
	]
  },
  "sap.ui5": {
	"_version": "1.1.0",
	"rootView": "sap.ui.demo.wt.view.App",
	"dependencies": {
	  "minUI5Version": "1.30",
	  "libs": {
		"sap.m": {}
	  }
	},
	"models": {
	  "i18n": {
		"type": "sap.ui.model.resource.ResourceModel",
		"settings": {
		  "bundleName": "sap.ui.demo.wt.i18n.i18n"
		}
	  }
	}
  }
}

The content of the manifest.json file is a configuration object in JSON format that contains all global application settings and parameters. The manifest file is called the descriptor for applications, components, and libraries and is also referred to as “descriptor” or “app descriptor” when used for applications. It is stored in the webapp folder and read by SAPUI5 to instantiate the component. There are three important sections defined by namespaces in the manifest.json file:

sap.app
The sap.app namespace contains the following application-specific attributes:
- id (mandatory): The namespace of our application component
  
  The ID must not exceed 70 characters. It must be unique and must correspond to the component ID/namespace.
- type: Defines what we want to configure, here: an application
- i18n: Defines the path to the resource bundle file
- title: Title of the application in handlebars syntax referenced from the app's resource bundle
- description: Short description text what the application does in handlebars syntax referenced from the app's resource bundle
- applicationVersion: The version of the application to be able to easily update the application later on
sap.ui
The sap.ui namespace contributes the following UI-specific attributes:
- technology: This value specifies the UI technology; in our case we use SAPUI5
- deviceTypes: Tells what devices are supported by the app: desktop, tablet, phone (all true by default)
- supportedThemes: An array containing a list of SAP themes supported by the app, for example sap_bluecrystal
sap.ui5
The sap.ui5 namespace adds SAPUI5-specific configuration parameters that are automatically processed by SAPUI5. The most important parameters are:
- rootView: If you specify this parameter, the component will automatically instantiate the view and use it as the root for this component
- dependencies: Here we declare the UI libraries used in the application
- models: In this section of the descriptor we can define models that will be automatically instantiated by SAPUI5 when the app starts. Here we can now define the local resource bundle. We define the name of the model "i18n" as key and specify the bundle file by namespace. As in the previous steps, the file with our translated texts is stored in the i18n folder and named i18n.properties. We simply prefix the path to the file with the namespace of our app. The manual instantiation in the app component's init method will be removed later in this step.
For compatibility reasons the root object and each of the sections state the descriptor version number 1.1.0 under the internal property _version. Features might be added or changed in future versions of the descriptor and the version number helps to identify the application settings by tools that read the descriptor.

Note

Properties of the resource bundle are enclosed in two curly brackets in the descriptor. This is not a SAPUI5 data binding syntax, but a variable reference to the resource bundle in the descriptor in handlebars syntax. The referred texts are not visible in the app built in this tutorial but can be read by an application container like the SAP Fiori launchpad.

webapp/i18n/i18n.properties

# App Descriptor
appTitle=Hello World
appDescription=A simple walkthrough app that explains the most important concepts of SAPUI5

# Hello Panel
showHelloButtonText=Say Hello
helloMsg=Hello {0}

In the resource bundle we simply add the texts for the app and add comments to separate the bundle texts semantically.

webapp/Component.js

sap.ui.define([
   "sap/ui/core/UIComponent",
   "sap/ui/model/json/JSONModel"
], function (UIComponent, JSONModel) {
   "use strict";
   return UIComponent.extend("sap.ui.demo.wt.Component", {
      metadata : {
            manifest: "json"
      },
      init : function () {
         // call the init function of the parent
         UIComponent.prototype.init.apply(this, arguments);
         // set data model
         var oData = {
            recipient : {
               name : "World"
            }
         };
         var oModel = new JSONModel(oData);
         this.setModel(oModel);
      }
   });
});

In the component's metadata section, we now replace the rootView property with the property key manifest and the value json. This defines a reference to the descriptor that will be loaded and parsed automatically when the component is instantiated. We can now completely remove the lines of code containing the model instantiation for our resource bundle. It is done automatically by SAPUI5 with the help of the configuration entries in the descriptor. We can also remove the dependency to sap/ui/model/resource/ResourceModel and the corresponding formal parameter ResourceModel because we will not use this inside our anonymous callback function.

Tip

In previous versions of SAPUI5, additional configuration settings for the app, like the service configuration, the root view, and the routing configuration, had to be added to the metadata section of the Component.js file. As of SAPUI5 version 1.30, we recommend that you define these settings in the manifest.json descriptor file. Apps and examples that were created based on an older SAPUI5 version still use the Component.js file for this purpose - so it is still supported, but not recommended.

Conventions

The descriptor file is named manifest.json and located in the webapp folder.
Use translatable strings for the title and the description of the app.