min

v1.0.0

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.

Usage

Hello World

You can initialize a new instance of the Min type with whichever type that implements min.Handler. An adapter for httprouter is included.

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("/", helloWorld)

    http.ListenAndServe(":8080", m)
}

func helloWorld(w http.ResponseWriter, r *http.Request) {
    fmt.Fprintln(w, "hello world!")
}

Route Parameters

min supports all the syntax variations for defining route parameters that the underlying router does. For instance, in the case of httprouter:

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", 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)
}

Route Grouping

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("/", apiRoot)
        // GET /api/ignacio
        apiRouter.Get("/:name", 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

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.

min users are meant to take advantage of context to make better use of middleware.

import (
    "context"
    "fmt"
    "log"
    "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)

    chain := min.Middleware(logger).Then(printer)
    m.Use(chain)

    apiRouter := m.NewGroup("/api")
    {
        apiRouter.Get("/", 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("/", greet)
            // GET /api/ignacio/goodbye
            nameRouter.Get("/goodbye", goodbye)
        }
    }

    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))
    })
}

// -- 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)
}