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/**
* Code from:
* https://github.com/expressjs/express/pull/2809
*
* Target Express version: { "express": "^4.14.0 <5.0.0" }
*
* This monkey patch allows to return Promises from middleware and route handlers, rejections will be handled automaticaly.
*
* Please note:
* If you return something from `(...) -> void` callbacks - you shoot your own leg.
* This could lead to double error handling if your callback handles error and returns Promise same time.
* So, please check your middlewares and routes for abnormal `Promise` returns before applying patch.
*
*/
var PACKAGE = require('express/package.json');
if (parseInt(PACKAGE.version.match(/^\d+/)[0]) !== 4) {
throw new Error("This patch could be applied only for Express 4. " +
"Express 5 will get it's own Promise handling.");
}
var Layer = require("express/lib/router/layer");
/*
// https://github.com/expressjs/express/blob/9302acc5e449768b3ca2b03701d5379d86453af5/lib/router/layer.js
// Target Function:
Layer.prototype.handle_request = function handle(req, res, next) {
var fn = this.handle;
if (fn.length > 3) {
// not a standard request handler
return next();
}
try {
fn(req, res, next);
} catch (err) {
next(err);
}
};
*/
if (!Layer.prototype.handle_request) {
throw new Error("Something terribly wrong just happened, " +
"there are no `Layer.prototype.handle_request` to apply patch to.");
}
Layer.prototype.handle_request = function handle(req, res, next) {
var fn = this.handle;
if (fn.length > 3) {
// not a standard request handler
return next();
}
try {
var maybe_promise = fn(req, res, next);
if (maybe_promise && maybe_promise.catch && typeof maybe_promise.catch === "function") {
maybe_promise.catch(next);
}
} catch (err) {
next(err);
}
};
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