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105 lines
3.8 KiB
105 lines
3.8 KiB
import {Model} from './Model'
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import {AbstractResultIterable} from '../builder/result/AbstractResultIterable'
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import {Connection} from '../connection/Connection'
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import {ModelBuilder} from './ModelBuilder'
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import {Instantiable} from '../../di'
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import {QueryRow} from '../types'
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import {collect, Collection} from '../../util'
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import {getFieldsMeta} from './Field'
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/**
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* Implementation of the result iterable that returns query results as instances of the defined model.
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*/
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export class ModelResultIterable<T extends Model<T>> extends AbstractResultIterable<T> {
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constructor(
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public readonly builder: ModelBuilder<T>,
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public readonly connection: Connection,
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/** The model that should be instantiated for each row. */
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protected readonly ModelClass: Instantiable<T>,
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) {
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super(builder, connection)
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}
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public get selectSQL(): string {
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return this.connection.dialect().renderSelect(this.builder)
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}
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async at(i: number): Promise<T | undefined> {
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const query = this.connection.dialect().renderRangedSelect(this.selectSQL, i, i + 1)
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const row = (await this.connection.query(query)).rows.first()
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if ( row ) {
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const inflated = await this.inflateRow(row)
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await this.processEagerLoads(collect([inflated]))
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return inflated
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}
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}
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async range(start: number, end: number): Promise<Collection<T>> {
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const query = this.connection.dialect().renderRangedSelect(this.selectSQL, start, end)
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const inflated = await (await this.connection.query(query)).rows.promiseMap<T>(row => this.inflateRow(row))
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await this.processEagerLoads(inflated)
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return inflated
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}
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async count(): Promise<number> {
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const query = this.connection.dialect().renderCount(this.selectSQL)
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const result = (await this.connection.query(query)).rows.first()
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return result?.extollo_render_count ?? 0
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}
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async all(): Promise<Collection<T>> {
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const result = await this.connection.query(this.selectSQL)
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const inflated = await result.rows.promiseMap<T>(row => this.inflateRow(row))
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await this.processEagerLoads(inflated)
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return inflated
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}
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/**
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* Given a query row, create an instance of the configured model class from it.
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* @param row
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* @protected
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*/
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protected async inflateRow(row: QueryRow): Promise<T> {
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const model = this.make<T>(this.ModelClass)
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const fields = getFieldsMeta(model)
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return model.assumeFromSource(
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this.connection.normalizeRow(row, fields),
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)
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}
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/**
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* Eager-load eager-loaded relations for the models in the query result.
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* @param results
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* @protected
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*/
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protected async processEagerLoads(results: Collection<T>): Promise<void> {
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if ( results.isEmpty() ) {
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// Nothing to load relations for, so no reason to perform more queries
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return
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}
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const eagers = this.builder.getEagerLoadedRelations()
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const model = this.make<T>(this.ModelClass)
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for ( const name of eagers ) {
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// TODO support nested eager loads?
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const relation = model.getRelation(name)
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const select = relation.buildEagerQuery(this.builder, results)
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const resultCount = await select.get().count()
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const allRelated = resultCount ? await select.get().collect() : collect()
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results.each(result => {
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const resultRelation = result.getRelation(name as any)
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const resultRelated = resultRelation.matchResults(allRelated as any)
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resultRelation.setValue(resultRelated as any)
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})
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}
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}
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clone(): ModelResultIterable<T> {
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return new ModelResultIterable(this.builder, this.connection, this.ModelClass)
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}
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}
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