Versioning

Violetear handle versions by using the Accept: application/vnd.* header.

This means that the URL won’t change, therefore instead of specifying the version on the URL something like this:

https://acme.tld/api/v2/foo

It can always be:

https://acme.tld/api/foo

But based on the request Accept: application/vnd.* header the corresponding version will be served:

https://acme.tld/api/foo
===>
GET /api/foo HTTP/1.1
Accept: application/vnd.acme.v2

Using the Fragment identifier #

To define what version to use, the # fragment identifier is used when declaring the routes.

The versionHeader constant is set to:

application/vnd.

This means that when defining a version only the string after application/vnd. is required:

application/vnd.[version]

Example:

package main

import (
	"fmt"
	"log"
	"net/http"

	"github.com/nbari/violetear"
)

func handleHello(w http.ResponseWriter, r *http.Request) {
	fmt.Fprintf(w, "Hi,  %s!", r.URL.Path[1:])
}
func handleHelloV2(w http.ResponseWriter, r *http.Request) {
	fmt.Fprintf(w, "version 2")
}

func main() {
	router := violetear.New()

	router.HandleFunc("/hello", handleHello, "GET, HEAD")
	router.HandleFunc("/hello#violetear.v2", handleHelloV2, "GET, HEAD, POST")

	log.Fatal(http.ListenAndServe(":8000", router))
}

In this example, there are 2 different handlers for the /hello/ request handleHello and handeHelloV2:

router.HandleFunc("/hello", handleHello, "GET, HEAD")
router.HandleFunc("/hello#violetear.v2", handleHelloV2, "GET, HEAD, POST")

To serve using the handleHelloV2, the request needs to contain the header:

Accept: application/vnd.violetear.v2

if not, will take as default the handler handleHello

Example of how to send the header using http or curl

Using the http client:

$ http 0:8000/hello "Accept: application/vnd.violetear.v2"

Using curl:

$ curl 0:8000/hello -H "Accept: application/vnd.violetear.v2"