Seatbelt

type seatbelt.App

A *seatbelt.App is the core of your application. It contains routing and middleware information, stores templates and internationalization data, and manages sessions and flashes.

It is not an HTTP server. While it does provide a Start() method for convenience, it is not intended for production use. Instead, you should create an instance of a *http.Server, and pass the *seatbelt.App as its Handler.

package main

import (
    "net/http"

    "github.com/go-seatbelt/seatbelt"
)

func main() {
    app := seatbelt.New()

    srv := &http.Server{
		    Addr:         ":3000",
		    Handler:      app,
		    ReadTimeout:  30 * time.Second,
		    WriteTimeout: 20 * time.Second,
    }

    log.Fatalln(srv.ListenAndServe())
}

func seatbelt.New(opts ...seatbelt.Opts) *seatbelt.App

Use seatbelt.New to create and configure a new instance of a *seatbelt.App using the given seabelt.Opts to configure it. The following options are available:

TemplateDir string The directory containing your HTML templates. Defaults to "templates".
LocaleDir string The directory containing your translation files. Defaults to an empty string, which disables translation support in your application.
SigningKey string The secret key used to sign the session cookie. Defaults to an empty string. Setting an empty string will cause Seatbelt to generate a master.key file at the root of your application, which Seatbelt picks up and uses to sign sessions. This generated secret is used for convenience in development only. Do not put this secret under source control, and set this value automatically by setting the SECRET environment variable in production.
SessionName string The name of the session cookie. Defaults to "_session".
SessionMaxAge int The max age that the session cookie is valid. Defaults to 365 days. Pass -1 if you want the session to never expire.
Reload bool Whether to reload the HTML templates and translation data from the filesystem on each request. Defaults to false. This is provided as a convenience in development, but significantly impacts performance. Do not enable this in production.
SkipServeFiles bool When true, this stops Seatbelt from serving static files from the public folder. Defaults to false, meaning that static files are served by default.
Funcs func(w http.ResponseWriter, r *http.Request) template.FuncMap HTML template functions to call from your templates. Defaults to nil, but please see the list of default functions.

package main

import (
    "html/template"
    "net/http"
    "os"

    "github.com/go-seatbelt/seatbelt"
)

func main() {
    app := seatbelt.New(seatbelt.Option{
        TemplateDir:    "templates",
        LocaleDir:      "locales",
        SigningKey:     os.Getenv("SECRET"),
        SessionName:    "_seatbelt",
        SessionMaxAge:  int(30 * 24 * time.Hour),
        Reload:         false,
        SkipServeFiles: false,
        Funcs: func(w http.ResponseWriter, r *http.Request) template.FuncMap {
            return template.FuncMap{
                "CurrentPath": func(path string) bool {
                    return r.URL.Path == path
                },
            }
        },
    })
}

func (app *seatbelt.App) Start(port string) error

The method Start() is a convenience method for starting an HTTP server that runs your application.

The started HTTP server is not suited for production use. Instead, you should create an instance of an *http.Server, and pass the *seatbelt.App as its Handler.

package main

import "github.com/go-seatbelt/seatbelt"

func main() {
    app := seatbelt.New()
    // Starts an HTTP server on http://localhost:3000
    app.Start(":3000")
}

func (app *seatbelt.App) Use(middleware ...seatbelt.MiddlewareFunc)

Registers HTTP middleware on the application.

package main

import (
	"log"

	"github.com/go-seatbelt/seatbelt"
)

// logger is HTTP middleware that logs the path of the current request.
func logger(fn func(c *seatbelt.Context) error) func(*seatbelt.Context) error {
	return func(c *seatbelt.Context) error {
		log.Println("received request:", c.Request().URL.Path)
		return fn(c)
	}
}

func main() {
	app := seatbelt.New()
	app.Use(logger)
}

func (app *seatbelt.App) UseStd(middleware ...func(http.Handler) http.Handler)

Registers standard library compatible HTTP middleware on the application.

package main

import (
    "log"
    "net/http"

    "github.com/go-seatbelt/seatbelt"
)

func logger(h http.Handler) http.Handler {
    return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
        log.Printf("received request: %s\n", r.URL.Path)
        h.ServeHTTP(w, r)
    })
}

func main() {
    app := seatbelt.New()
    app.UseStd(logger)
}

func (a seatbelt.App) SetErrorHandler(fn func(c seatbelt.Context, err error))

Sets the given function as the application-wide error handler. When this handler isn't set, the default behaviour is to log the error, and either reply with the error (for idempotent request) or redirect to the referrer with a flash message containing the error (for all other requests).

package main

import (
    "log"
    "net/http"
    "strings"

    "github.com/go-seatbelt/seatbelt"
)

func handleErr(c *seatbelt.Context, err error) {
    accept := c.Request().Header.Get("Accept")

    if strings.Contains(accept, "application/json") {
        c.JSON(500, map[string]string{
            "Error": err.Error(),
        })
        return
    }

    if strings.Contains(accept, "text/html") {
        c.Render("error", map[string]any{
            "Error": error
        }, seatbelt.RenderOptions{
            StatusCode: 500,
        })
        return
    }

    return c.String(500, "Error: " + err.Error())
}

func main() {
    app := seatbelt.New()
    app.SetErrorHandler(handleErr)
}

func (app seatbelt.App) Get(pattern string, func(c seatbelt.Context) error

Registers the given function as an HTTP handler, responding to GET requests at the given path.

Path parameters can be registered on the given URL handler, and accessed in the handler by using c.PathParam.

package main

import (
    "log"
    "net/http"
    "strings"

    "github.com/go-seatbelt/seatbelt"
)

func main() {
    app := seatbelt.New()
    app.Get("/", func(c *seatbelt.Context) error {
        return c.String(200, "Hello, world!")
    })
    app.Get("/users/{id}", func(c *seatbelt.Context) error {
        // Returns the ID provided in the path.
        return c.String(200, c.PathParam("id"))
    })
    app.Start(":3000")
}

package main

import "github.com/go-seatbelt/seatbelt"

// Creates a server that registers a handler on the path "/", and replies with
// "Hello, world!".
func main() {
    app := seatbelt.New()

    app.Get("/", func (c *seatbelt.Context) error {
        return c.String(200, "Hello, world!")
    })

    app.Start(":3000")
}

seatbelt.App

seatbelt.Context

API Reference