alfresco-ng2-components/docs/core/app-config.service.md

Added, Status

Added	Status
v2.0.0	Active

App Config service

Supports app configuration settings, stored server side.

Class members

Methods

• get(key: string = null, defaultValue?: T = null): T
  Gets the value of a named property.
  • key: string - Name of the property
  • defaultValue: T - (Optional) Value to return if the key is not found
  • Returns T - Value of the property
• getLocationHostname(): string
  Gets the location.hostname property.
  • Returns string - Value of the property
• getLocationPort(prefix: string = ""): string
  Gets the location.port property.
  • prefix: string - Text added before port value
  • Returns string - Port with prefix
• getLocationProtocol(): string
  Gets the location.protocol value.
  • Returns string -
• load(): Promise<any>
  Loads the config file.
  • Returns Promise<any> - Notification when loading is complete
• select(property: string = null): Observable<any>
  Requests notification of a property value when it is loaded.
  • property: string - The desired property value
  • Returns Observable<any> - Property value, when loaded

Details

The AppConfigService service provides support for loading and accessing global application configuration settings that you store on the server side in the form of a JSON file.

You may need this service when deploying your ADF-based application to production servers.

There can be more than one server running web apps with different settings, like different addresses for Alfresco Content/Process services.

Or there is a need to change global settings for all the clients.

The service is already pre-configured to look for the "app.config.json" file in the application root address.

That allows deploying ADF-based web applications to multiple servers together with different settings files, for example having development, staging or production environments.

Example of the default settings file content:

app.config.json

{
    "ecmHost": "http://localhost:3000/ecm",
    "bpmHost": "http://localhost:3000/bpm",
    "application": {
        "name": "Alfresco"
    }
}

Please note that settings above are default ones coming with the server. You can override the values in your custom app.config.json file if needed.

You can also change the path or name of the configuration file when importing the CoreModule in your main application.

...
@NgModule({
    imports: [
        ...
        CoreModule.forRoot({
            appConfigFile: 'app.production.config.json'
        })
    ],
    ...
}
export class AppModule { }

Below is a simple example of using the AppConfigService in practice.

app.component.ts

import { AppConfigService } from '@alfresco/adf-core';

@Component({...})
export class AppComponent {

    constructor(appConfig: AppConfigService) {

        // get nested properties by the path
        console.log(appConfig.get('application.name'));

        // use generics for type safety 
        let version: number = appConfig.get<number>('version');
        console.log(version);
    }
}

Your custom components can also benefit from the AppConfigService, you can put an unlimited number of settings and optionally a nested JSON hierarchy.

Variable substitution in configuration strings

The AppConfigService also supports a limited set of variable substitutions to greatly simplify certain scenarios.

{
    "ecmHost": "{protocol}//{hostname}:{port}/ecm",
    "bpmHost": "{protocol}//{hostname}:{port}/bpm",
    "application": {
        "name": "Alfresco"
    }
}

The supported variables are:

Variable name	Runtime value
protocol	location.protocol
hostname	location.hostname
port	location.port

App Config onLoad Stream

When the app config is loaded correctly an onChange event is sent with the whole set app config properties. This comes in handy when a component wants to react to some property change or interact with the app config when it's correctly loaded.

    appConfig.onLoad.subscribe((appConfig) => {
        console.log(appConfig); //this is the representation of the app-config
    });

We have added also the select method where the user can give the property name which wants to be notified the when the app config is loaded and get the value.

    appconfig : {
        logLevel : 'trace'
    }

    
    appConfig.select('logLevel').subscribe((logLevelValue) => {
        console.log(logLevelValue); //this will be 'trace';
    });