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gomponents/http/handler.go
Markus Wüstenberg 0001b1d609
Add http.Adapt function (#92)
In the new package `http`, an `Adapt` function converts a `Handler` into a `http.HandlerFunc` from the `http` stdlib package.
2021-10-08 15:00:20 +02:00

43 lines
1.2 KiB
Go

// Package http provides adapters to render gomponents in http handlers.
package http
import (
"net/http"
g "github.com/maragudk/gomponents"
)
// Handler is like http.Handler but returns a Node and an error.
// See Adapt for how errors are translated to HTTP responses.
type Handler = func(http.ResponseWriter, *http.Request) (g.Node, error)
type errorWithStatusCode interface {
StatusCode() int
}
// Adapt a Handler to a http.Handlerfunc.
// The returned Node is rendered to the ResponseWriter, in both normal and error cases.
// If the Handler returns an error, and it implements a "StatusCode() int" method, that HTTP status code is sent
// in the response header. Otherwise, the status code http.StatusInternalServerError (500) is used.
func Adapt(h Handler) http.HandlerFunc {
return func(w http.ResponseWriter, r *http.Request) {
n, err := h(w, r)
if err != nil {
switch v := err.(type) {
case errorWithStatusCode:
w.WriteHeader(v.StatusCode())
default:
w.WriteHeader(http.StatusInternalServerError)
}
}
if n == nil {
return
}
if err := n.Render(w); err != nil {
http.Error(w, "error rendering node: "+err.Error(), http.StatusInternalServerError)
}
}
}