Initial Commit

webfinger/handler.go

@@ -0,0 +1,46 @@
+package webfinger
+
+import (
+	"encoding/json"
+	"net/http"
+)
+
+// Handler handles WebFinger requests to an HTTP server
+type Handler struct {
+	// DescriptorFunc is the function used to resolve resource strings
+	// to WebFinger descriptors. It's called on every request to the
+	// WebFinger endpoint. The errors it returns are handled by ErrorHandler.
+	DescriptorFunc func(resource string) (*Descriptor, error)
+
+	// ErrorHandler handles any errors that occur in the process of performing
+	// a WebFinger lookup. If not provided, a simple default handler is used.
+	ErrorHandler func(err error, res http.ResponseWriter)
+}
+
+// ServeHTTP implements the http.Handler interface
+func (h Handler) ServeHTTP(res http.ResponseWriter, req *http.Request) {
+	if h.ErrorHandler == nil {
+		h.ErrorHandler = func(err error, res http.ResponseWriter) {
+			http.Error(res, err.Error(), http.StatusInternalServerError)
+		}
+	}
+
+	descriptor, err := h.DescriptorFunc(req.URL.Query().Get("resource"))
+	if err != nil {
+		h.ErrorHandler(err, res)
+		return
+	}
+
+	data, err := json.Marshal(descriptor)
+	if err != nil {
+		h.ErrorHandler(err, res)
+		return
+	}
+
+	res.Header().Set("Content-Type", "application/jrd+json")
+	_, err = res.Write(data)
+	if err != nil {
+		h.ErrorHandler(err, res)
+		return
+	}
+}