OpenSlides/client/src/app/core/ui-services/config.service.ts

75 lines
2.2 KiB
TypeScript

import { Injectable } from '@angular/core';
import { Observable, BehaviorSubject } from 'rxjs';
import { Config } from '../../shared/models/core/config';
import { DataStoreService } from '../core-services/data-store.service';
/**
* Handler for config variables.
*
* @example
* ```ts
* this.configService.get('general_event_name').subscribe(value => {
* console.log(value);
* });
* ```
*
* @example
* ```ts
* const value = this.configService.instant('general_event_name');
* ```
*/
@Injectable({
providedIn: 'root'
})
export class ConfigService {
/**
* Stores a subject per key. Values are published, if the DataStore gets an update.
*/
private configSubjects: { [key: string]: BehaviorSubject<any> } = {};
/**
* Listen for changes of config variables.
*/
public constructor(private DS: DataStoreService) {
this.DS.getChangeObservable(Config).subscribe(data => {
// on changes notify the observers for specific keys.
if (this.configSubjects[data.key]) {
this.configSubjects[data.key].next(data.value);
}
});
}
/**
* Get the constant named by key from the DataStore. If the DataStore isn't up to date or
* not filled via autoupdates the results may be wrong/empty. Use this with caution.
*
* Usefull for synchronos code, e.g. during generation of PDFs, when the DataStore is filled.
*
* @param key The config value to get from.
*/
public instant<T>(key: string): T {
const values = this.DS.filter<Config>('core/config', value => value.key === key);
if (values.length > 1) {
throw new Error('More keys found then expected');
} else if (values.length === 1) {
return values[0].value as T;
} else {
return;
}
}
/**
* Get an observer for the config value given by the key.
*
* @param key The config value to get from.
*/
public get<T>(key: string): Observable<T> {
if (!this.configSubjects[key]) {
this.configSubjects[key] = new BehaviorSubject<any>(this.instant(key));
}
return this.configSubjects[key].asObservable() as Observable<T>;
}
}