polyserve
Version:
A simple dev server for bower components
82 lines • 3.18 kB
JavaScript
;
/**
* @license
* Copyright (c) 2016 The Polymer Project Authors. All rights reserved.
* This code may only be used under the BSD style license found at
* http://polymer.github.io/LICENSE.txt
* The complete set of authors may be found at
* http://polymer.github.io/AUTHORS.txt
* The complete set of contributors may be found at
* http://polymer.github.io/CONTRIBUTORS.txt
* Code distributed by Google as part of the polymer project is also
* subject to an additional IP rights grant found at
* http://polymer.github.io/PATENTS.txt
*/
Object.defineProperty(exports, "__esModule", { value: true });
function transformResponse(transformer) {
return (req, res, next) => {
let ended = false;
const chunks = [];
let _shouldTransform = null;
// Note: this function memoizes its result.
function shouldTransform() {
if (_shouldTransform == null) {
const successful = res.statusCode >= 200 && res.statusCode < 300;
_shouldTransform =
successful && !!transformer.shouldTransform(req, res);
}
return _shouldTransform;
}
const _write = res.write;
res.write = function (chunk, cbOrEncoding, cbOrFd) {
if (ended) {
_write.call(this, chunk, cbOrEncoding, cbOrFd);
return false;
}
if (shouldTransform()) {
const buffer = (typeof chunk === 'string') ?
new Buffer(chunk, cbOrEncoding) :
chunk;
chunks.push(buffer);
return true;
}
else {
return _write.call(this, chunk, cbOrEncoding, cbOrFd);
}
};
const _end = res.end;
res.end = function (chunk, cbOrEncoding, cbOrFd) {
if (ended)
return false;
ended = true;
if (shouldTransform()) {
if (chunk) {
const buffer = (typeof chunk === 'string') ?
new Buffer(chunk, cbOrEncoding) :
chunk;
chunks.push(buffer);
}
const body = Buffer.concat(chunks).toString('utf8');
let newBody = body;
try {
newBody = transformer.transform(req, res, body);
}
catch (e) {
console.warn('Error', e);
}
// TODO(justinfagnani): re-enable setting of content-length when we know
// why it was causing truncated files. Could be multi-byte characters.
// Assumes single-byte code points!
// res.setHeader('Content-Length', `${newBody.length}`);
res.removeHeader('Content-Length');
return _end.call(this, newBody);
}
else {
return _end.call(this, chunk, cbOrEncoding, cbOrFd);
}
};
next();
};
}
exports.transformResponse = transformResponse;
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