103 lines
3.1 KiB
JavaScript
103 lines
3.1 KiB
JavaScript
const http = require('http');
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const Router = require('trouter');
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const { parse } = require('querystring');
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const parser = require('@polka/url');
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function lead(x) {
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return x.charCodeAt(0) === 47 ? x : ('/' + x);
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}
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function value(x) {
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let y = x.indexOf('/', 1);
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return y > 1 ? x.substring(0, y) : x;
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}
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function mutate(str, req) {
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req.url = req.url.substring(str.length) || '/';
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req.path = req.path.substring(str.length) || '/';
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}
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function onError(err, req, res, next) {
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let code = (res.statusCode = err.code || err.status || 500);
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res.end(err.length && err || err.message || http.STATUS_CODES[code]);
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}
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class Polka extends Router {
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constructor(opts={}) {
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super(opts);
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this.apps = {};
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this.wares = [];
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this.bwares = {};
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this.parse = parser;
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this.server = opts.server;
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this.handler = this.handler.bind(this);
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this.onError = opts.onError || onError; // catch-all handler
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this.onNoMatch = opts.onNoMatch || this.onError.bind(null, { code:404 });
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}
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add(method, pattern, ...fns) {
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let base = lead(value(pattern));
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if (this.apps[base] !== void 0) throw new Error(`Cannot mount ".${method.toLowerCase()}('${lead(pattern)}')" because a Polka application at ".use('${base}')" already exists! You should move this handler into your Polka application instead.`);
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return super.add(method, pattern, ...fns);
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}
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use(base, ...fns) {
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if (typeof base === 'function') {
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this.wares = this.wares.concat(base, fns);
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} else if (base === '/') {
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this.wares = this.wares.concat(fns);
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} else {
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base = lead(base);
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fns.forEach(fn => {
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if (fn instanceof Polka) {
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this.apps[base] = fn;
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} else {
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let arr = this.bwares[base] || [];
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arr.length > 0 || arr.push((r, _, nxt) => (mutate(base, r),nxt()));
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this.bwares[base] = arr.concat(fn);
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}
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});
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}
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return this; // chainable
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}
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listen() {
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(this.server = this.server || http.createServer()).on('request', this.handler);
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this.server.listen.apply(this.server, arguments);
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return this;
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}
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handler(req, res, info) {
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info = info || this.parse(req);
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let fns=[], arr=this.wares, obj=this.find(req.method, info.pathname);
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req.originalUrl = req.originalUrl || req.url;
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let base = value(req.path = info.pathname);
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if (this.bwares[base] !== void 0) {
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arr = arr.concat(this.bwares[base]);
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}
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if (obj) {
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fns = obj.handlers;
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req.params = obj.params;
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} else if (this.apps[base] !== void 0) {
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mutate(base, req); info.pathname=req.path; //=> updates
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fns.push(this.apps[base].handler.bind(null, req, res, info));
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} else if (fns.length === 0) {
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fns.push(this.onNoMatch);
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}
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// Grab addl values from `info`
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req.search = info.search;
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req.query = parse(info.query);
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// Exit if only a single function
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let i=0, len=arr.length, num=fns.length;
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if (len === i && num === 1) return fns[0](req, res);
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// Otherwise loop thru all middlware
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let next = err => err ? this.onError(err, req, res, next) : loop();
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let loop = _ => res.finished || (i < len) && arr[i++](req, res, next);
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arr = arr.concat(fns);
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len += num;
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loop(); // init
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}
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}
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module.exports = opts => new Polka(opts);
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