v1.1.0
min is a BYO*, minimalistic web framework that builds on top of your router
of choice and adds some additional functionality—namely, middleware chaining
and route grouping. It's meant to be used on projects large and small that
require flexibility, and varying degrees of custom code and architecture.
This version of min integrates some of the lessons I've learned recently. For
this release, I decided to focus on orthogonality and composability, and took a
"pure" TDD approach to the API rewrite. The result is a much smaller library
with the same functionality, minus some unnecessary abstractions.
This package takes some inspiration from design decisions in
chi and
gin.
You can initialize a new instance of the Min type with whichever type that
implements min.Handler. An adapter for
httprouter is included.
package main
import (
"fmt"
"net/http"
"github.com/julienschmidt/httprouter"
"github.com/arturovm/min"
"github.com/arturovm/min/adapter"
)
func main() {
a := &adapter.Httprouter{Router: httprouter.New()}
m := min.New(a)
m.Get("/", http.HandlerFunc(helloWorld))
http.ListenAndServe(":8080", m)
}
func helloWorld(w http.ResponseWriter, r *http.Request) {
fmt.Fprintln(w, "hello world!")
}min supports all the syntax variations for defining route parameters that
the underlying router does. For instance, in the case of httprouter:
package main
import (
"fmt"
"net/http"
"github.com/julienschmidt/httprouter"
"github.com/arturovm/min"
"github.com/arturovm/min/adapter"
)
func main() {
a := &adapter.Httprouter{Router: httprouter.New()}
m := min.New(a)
m.Get("/:name", http.HandlerFunc(greet))
http.ListenAndServe(":8080", m)
}
func greet(w http.ResponseWriter, r *http.Request) {
name := httprouter.ParamsFromContext(r.Context()).ByName("name")
fmt.Fprintf(w, "hello %s!", name)
}package main
import (
"fmt"
"net/http"
"github.com/julienschmidt/httprouter"
"github.com/arturovm/min"
"github.com/arturovm/min/adapter"
)
func main() {
a := &adapter.Httprouter{Router: httprouter.New()}
m := min.New(a)
apiRouter := m.NewGroup("/api")
{
// GET /api
apiRouter.Get("/", http.HandlerFunc(apiRoot))
// GET /api/ignacio
apiRouter.Get("/:name", http.HandlerFunc(greet))
}
http.ListenAndServe(":8080", m)
}
func apiRoot(w http.ResponseWriter, r *http.Request) {
fmt.Fprintln(w, "api root")
}
func greet(w http.ResponseWriter, r *http.Request) {
name := httprouter.ParamsFromContext(r.Context()).ByName("name")
fmt.Fprintf(w, "hello %s!", name)
}Middleware in min are simply functions that take an http.Handler (the one
next in the chain) and return another one. They are resolved in the order that
they are chained. You can chain them together with the Middleware.Then
method.
Entry middleware is executed from the start of the request and hands off to the
handler at the end of the chain. Exit middleware is executed from after the
handler has returned onwards. You are free to keep using the Group.Use API,
which has become synonymous with Group.Entry.
min users are meant to take advantage of context to make better use of
middleware.
package main
import (
"context"
"encoding/json"
"fmt"
"log"
"net/http"
"github.com/julienschmidt/httprouter"
"github.com/arturovm/min"
"github.com/arturovm/min/adapter"
)
type whiplashRequest struct {
Whip string `json:"whip"`
Lash string `json:"lash"`
}
func main() {
a := &adapter.Httprouter{Router: httprouter.New()}
m := min.New(a)
chain := min.Middleware(logger).Then(printer)
m.Use(chain)
apiRouter := m.NewGroup("/api")
{
apiRouter.Get("/", http.HandlerFunc(apiRoot))
nameRouter := apiRouter.NewGroup("/:name")
{
// Every request sent to routes defined on this sub-router will now
// have a reference to a name in its context.
// Useful for RESTful design.
nameRouter.Use(nameExtractor)
// GET /api/ignacio
nameRouter.Get("/", http.HandlerFunc(greet))
// GET /api/ignacio/goodbye
nameRouter.Get("/goodbye", http.HandlerFunc(goodbye))
whiplashRouter := nameRouter.NewGroup("/whiplash")
{
// We can take advantage of generics and deserialize JSON data
// on every reqest sent to this sub-router.
whiplashRouter.Entry(deserializer[whiplashRequest])
whiplashRouter.Post("/", http.HandlerFunc(createWhiplash))
}
}
}
http.ListenAndServe(":8080", m)
}
// -- Middleware --
// a simple logger
func logger(next http.Handler) http.Handler {
return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
log.Printf("| %s %s", r.Method, r.URL)
next.ServeHTTP(w, r)
})
}
// a useless middleware that prints text
func printer(next http.Handler) http.Handler {
return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
log.Println("this prints some text")
next.ServeHTTP(w, r)
})
}
// extracts a name from the URL and injects it into the request's context
func nameExtractor(next http.Handler) http.Handler {
return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
name := httprouter.ParamsFromContext(r.Context()).ByName("name")
ctx := context.WithValue(r.Context(), "name", name)
next.ServeHTTP(w, r.WithContext(ctx))
})
}
func deserializer[T any](next http.Handler) http.Handler {
return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
var dst T
err := json.NewDecoder(r.Body).Decode(&dst)
if err != nil {
w.WriteHeader(http.StatusBadRequest)
return
}
ctx := context.WithValue(r.Context(), "data", dst)
next.ServeHTTP(w, r.WithContext(ctx))
})
}
// -- Handlers --
func apiRoot(w http.ResponseWriter, r *http.Request) {
fmt.Fprintln(w, "api root")
}
// greets the user with :name
func greet(w http.ResponseWriter, r *http.Request) {
name := r.Context().Value("name").(string)
fmt.Fprintf(w, "hello %s!", name)
}
// says "bye" to the user with :name
func goodbye(w http.ResponseWriter, r *http.Request) {
name := r.Context().Value("name").(string)
fmt.Fprintf(w, "bye %s!", name)
}
// creates a whiplash thingamabob
func createWhiplash(w http.ResponseWriter, r *http.Request) {
data := r.Context().Value("data").(whiplashRequest)
fmt.Fprintf(w, "whip: %s, lash: %s", data.Whip, data.Lash)
}