63 lines
1.6 KiB
JavaScript
63 lines
1.6 KiB
JavaScript
// @flow
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import querystring from 'querystring';
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import { InvalidRequestError } from '../../errors';
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import { type Context } from 'koa';
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export default function pagination(options?: Object) {
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return async function paginationMiddleware(
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ctx: Context,
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next: () => Promise<*>
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) {
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const opts = {
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defaultLimit: 15,
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defaultOffset: 0,
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maxLimit: 100,
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...options,
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};
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let query = ctx.request.query;
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let body: Object = ctx.request.body;
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let limit = query.limit || body.limit;
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let offset = query.offset || body.offset;
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if (limit && isNaN(limit)) {
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throw new InvalidRequestError(`Pagination limit must be a valid number`);
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}
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if (offset && isNaN(offset)) {
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throw new InvalidRequestError(`Pagination offset must be a valid number`);
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}
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limit = parseInt(limit || opts.defaultLimit, 10);
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offset = parseInt(offset || opts.defaultOffset, 10);
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if (limit > opts.maxLimit) {
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throw new InvalidRequestError(
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`Pagination limit is too large (max ${opts.maxLimit})`
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);
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}
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if (limit <= 0) {
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throw new InvalidRequestError(`Pagination limit must be greater than 0`);
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}
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if (offset < 0) {
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throw new InvalidRequestError(
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`Pagination offset must be greater than or equal to 0`
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);
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}
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ctx.state.pagination = {
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limit: limit,
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offset: offset,
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};
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// $FlowFixMe
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query.limit = ctx.state.pagination.limit;
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// $FlowFixMe
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query.offset = ctx.state.pagination.offset + query.limit;
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ctx.state.pagination.nextPath = `/api${
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ctx.request.path
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}?${querystring.stringify(query)}`;
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return next();
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};
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}
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