asxpo - backend.go

  package backend
  
  import (
  	"encoding/json"
  	"errors"
  	"io"
  	"net/http"
  	"strings"
  
  	"vimagination.zapto.org/httpbuffer"
  )
  
  type backend struct {
  	path string
  	http.ServeMux
  }
  
  func New(path string) http.Handler {
  	b := &backend{
  		path: path,
  	}
  
  	var mux http.ServeMux
  
  	mux.Handle("GET /modules", handler(b.listModules))
  	mux.Handle("GET /modules/{module}", handler(b.getModule))
  	mux.Handle("PUT /modules/{module}", handler(b.setModule))
  	mux.Handle("POST /modules/{module}/{name}", handler(b.renameModule))
  	mux.Handle("DELETE /modules/{module}", handler(b.deleteModule))
  
  	mux.Handle("GET /modules/{module}/{type}", handler(b.getType))
  	mux.Handle("PUT /modules/{module}/{type}", handler(b.setType))
  	mux.Handle("PATCH /modules/{module}/{type}", handler(b.updateType))
  	mux.Handle("POST /modules/{module}/{type}/{name}", handler(b.renameType))
  	mux.Handle("DELETE /modules/{module}/{type}", handler(b.deleteType))
  
  	return &mux
  }
  
  type handler func(w http.ResponseWriter, r *http.Request) error
  
  func (h handler) ServeHTTP(w http.ResponseWriter, r *http.Request) {
  	httpbuffer.Handler{
  		Handler: http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
  			if err := h(w, r); err != nil {
  				http.Error(w, err.Error(), responseCode(err))
  			}
  		}),
  	}.ServeHTTP(w, r)
  }
  
  var httpErrors = map[error]int{
  	ErrDuplicateName: http.StatusConflict,
  	ErrInvalidName:   http.StatusUnprocessableEntity,
  	ErrNoModule:      http.StatusNotFound,
  	ErrNoType:        http.StatusNotFound,
  	ErrNoPatch:       http.StatusUnprocessableEntity,
  	io.EOF:           http.StatusBadRequest,
  }
  
  func responseCode(err error) int {
  	for e, resp := range httpErrors {
  		if errors.Is(err, e) {
  			return resp
  		}
  	}
  
  	if _, ok := errors.AsType[*json.SyntaxError](err); ok {
  		return http.StatusBadRequest
  	}
  
  	return http.StatusInternalServerError
  }
  
  func validatePaths(paths ...string) bool {
  	for _, path := range paths {
  		if strings.ContainsAny(path, "/\x00") {
  			return false
  		}
  	}
  
  	return true
  }