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// Package http provides adapters to render gomponents in http handlers.
package http
import (
"net/http"
g "go.alanpearce.eu/gomponents"
)
// Handler is like [http.Handler] but returns a [g.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 [g.Node] is rendered to the [http.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)
}
}
}
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