Express content negotiation functions
Express content negotiation functions.
$ npm install express-negotiate
Require the module to add the request.negotiate method:
var express =negotiate = ;
Then use in the route handler:
Each handler key is either a full mimetype string, or a file extension string.
To prioritise handlers, simply append a quality in the same notation as the client uses when specifying an Accept header:
Note that the handler priority is only used after the priorities specified by any Accept header in the request have been considered. A priority cannot be specified on the 'default' handler.
When the same handler can be used for multiple types, then they can be combined in the string:
If there are no acceptable handlers, and no 'default' handler is specified, then req.negotiate will throw a negotiate.NotAcceptable error. This can be caught and handled using express error handling:
In some cases, it is preferable to call next(err) rather than throw an error. If negotiate is passed the 'next' callback function, it will call that instead:
By parsing out any filename extension on the route, and passing this to req.negotiate, the client can force a particular Content-Type regardless of the Accept header.
Picking up the filename extension on a "catch-all" route is a little trickier. The following example uses a regex to achieve this:
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