iceshrimp/packages/backend/src/server/api/mastodon/helpers/pagination.ts
2023-10-04 23:07:37 +02:00

84 lines
3.1 KiB
TypeScript

import { ObjectLiteral, SelectQueryBuilder } from "typeorm";
import config from "@/config/index.js";
import { convertId, IdType } from "../../index.js";
export class PaginationHelpers {
public static makePaginationQuery<T extends ObjectLiteral>(
q: SelectQueryBuilder<T>,
sinceId?: string,
maxId?: string,
minId?: string,
idField: string = `${q.alias}.id`,
) {
if (sinceId && minId) throw new Error("Can't user both sinceId and minId params");
if (sinceId && maxId) {
q.andWhere(`${idField} > :sinceId`, {sinceId: sinceId});
q.andWhere(`${idField} < :maxId`, {maxId: maxId});
q.orderBy(`${idField}`, "DESC");
}
if (minId && maxId) {
q.andWhere(`${idField} > :minId`, {minId: minId});
q.andWhere(`${idField} < :maxId`, {maxId: maxId});
q.orderBy(`${idField}`, "ASC");
} else if (sinceId) {
q.andWhere(`${idField} > :sinceId`, {sinceId: sinceId});
q.orderBy(`${idField}`, "DESC");
} else if (minId) {
q.andWhere(`${idField} > :minId`, {minId: minId});
q.orderBy(`${idField}`, "ASC");
} else if (maxId) {
q.andWhere(`${idField} < :maxId`, {maxId: maxId});
q.orderBy(`${idField}`, "DESC");
} else {
q.orderBy(`${idField}`, "DESC");
}
return q;
}
/**
*
* @param query
* @param limit
* @param reverse whether the result needs to be .reverse()'d. Set this to true when the parameter minId is not undefined in the original request.
*/
public static async execQuery<T extends ObjectLiteral>(query: SelectQueryBuilder<T>, limit: number, reverse: boolean): Promise<T[]> {
// We fetch more than requested because some may be filtered out, and if there's less than
// requested, the pagination stops.
const found = [];
const take = Math.floor(limit * 1.5);
let skip = 0;
try {
while (found.length < limit) {
const notes = await query.take(take).skip(skip).getMany();
found.push(...notes);
skip += take;
if (notes.length < take) break;
}
} catch (error) {
return [];
}
if (found.length > limit) {
found.length = limit;
}
return reverse ? found.reverse() : found;
}
public static appendLinkPaginationHeader(args: any, ctx: any, res: any, defaultLimit: number): void {
const link: string[] = [];
const limit = args.limit ?? defaultLimit;
if (res.maxId) {
const l = `<${config.url}/api${ctx.path}?limit=${limit}&max_id=${convertId(res.maxId, IdType.MastodonId)}>; rel="next"`;
link.push(l);
}
if (res.minId) {
const l = `<${config.url}/api${ctx.path}?limit=${limit}&min_id=${convertId(res.minId, IdType.MastodonId)}>; rel="prev"`;
link.push(l);
}
if (link.length > 0) {
ctx.response.append('Link', link.join(', '));
}
}
}