HTTP is amazing, it has amazing features that most of us aren't using. One of
these features are trailing headers. These are headers that can be send after
you've already written your initial HTTP headers. The only caveat is that they
only work with transfer-encoding: chunked, luckly, this is enabled by default
in Nodejs.
The module can be downloaded from the npm registry:
npm install --save trailers
The --save tells npm to automatically add the installed version to your
package.json
When using this module, nothing changes how you and program your Node.js
applications. The only difference is that you can write headers AFTER you've
written the headers of your response. You can still use res.setHeaders just
like you would normally do.
To run this module simply include it in your application:
require('trailers');That's it. Everything is magically fixed.
The module overrides the prototypes of the OutgoingMessage class in Node.js
which is what you get a Response object in a HTTP server. The setHeader
method is overridden method to check if the headers are already flushed to the
client and queues the headers in a new trailers object when they are already
written. We override the end method so we can flush these headers using the
addTrailers method.
MIT