vapr-compress
v0.6.1
Published
A compression plugin for Vapr
Downloads
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Maintainers
Readme
vapr-compress ![Build Status](https://travis-ci.org/JoshuaWise/vapr-compress.svg?branch=master)
Installation
npm install --save vapr
npm install --save vapr-compress
Usage
This plugin applies standard compression to Vapr responses.
const compress = require('vapr-compress');
const app = require('vapr')();
const route = app.get('/foo');
route.use(compress());
route.use((req) => {
return [['hello world']]; // This will be gzipped
});
Details
This plugin utilizes content negotiation to decide when to compress a response. It will try to use the Transfer-Encoding header if supported by the client (as indicated by the TE header), but will fallback to the Content-Encoding/Accept-Encoding headers when necessary. Both the gzip and deflate encodings are supported, but gzip will be prioritized when the client has not indicated a preference.
If the response body is null
or undefined
, compression will be skipped. However, empty strings and buffers are still considered eligible (for the sake of cache coherence, response size is not taken into consideration by default). Compression is also skipped for HEAD
requests, but headers are still set as if it were a GET
request.
Unless the forced
option is used or the only
option is set to "transfer-encoding"
, the Vary header will be automatically updated to make caches aware of the content negotiation.
Options
Any options passed to the plugin are forwarded to the zlib core module. In addition, the behavior of the plugin can be customized with the options below.
options.only = null
This option is used to restrict compression to either "content-encoding"
or "transfer-encoding"
, disabling the opposite style.
route.use(compress({ only: 'transfer-encoding' }));
options.aggressive = false
By default, if the client doesn't provide any content negotiation headers, compression will be skipped. However, if aggressive
is true
, compression (Content-Encoding) will be used in such cases.
route.use(compress({ aggressive: true }));
Since the
aggressive
option modifies the behavior of Content-Encoding compression, it cannot be used when theonly
option is set to"transfer-encoding"
.
options.forced = null
This option is used to bypass content negotiation. It can be set to either "content-encoding"
or "transfer-encoding"
, indicating which style of compression to use.
route.use(compress({ forced: 'content-encoding' }));
Since the
aggressive
andonly
options modify the behavior of content negotiation but theforced
option turns off content negotiation entirely, the neither of the former options can be used in combination withforced
.
options.anyStatus = false
The default behavior is to skip responses that have a status code of 300
or higher. If this option is set to true
, however, responses of any status code will be eligible for compression.
route.use(compress({ anyStatus: true }));
options.condition = null
Optionally, a condition
function can be provided to bypass compression on a per-request basis. For each eligible request, the function will be invoked with request
and response
as arguments. If the function does not return true
, compression will be skipped for that request.
route.use(compress({
anyStatus: true,
condition: (req, res) => res.code < 500,
}));