Abstract storage.

cmd/spaceapi-server/main.go

@@ -6,9 +6,8 @@ import (
 	"fmt"
 	"log"
 	"net/http"
-	"os"
 
-	"git.hacknology.de/projekte/spaceapi.git"
+	"git.hacknology.de/projekte/spaceapi"
 )
 
 var (
@@ -23,43 +22,30 @@ func main() {
 	flag.StringVar(&statusFile, "status-file", statusFile, "Status file to modify.")
 	flag.Parse()
 
-	status, err := readCurrentState(statusFile)
+	storage, err := spaceapi.Open(statusFile, false)
 	if err != nil {
-		log.Fatalf("Error reading state: %s", err)
+		log.Fatalf("Error opening data file: %s", err)
 	}
 
-	http.Handle("/spaceapi/status.json", handleReadStatus(status))
-	http.Handle("/spaceapi/status/state", handleSetState(status))
+	http.Handle("/spaceapi/status.json", handleReadStatus(storage.Status))
+	http.Handle("/spaceapi/status/state", handleSetState(storage))
 	http.Handle("/", http.RedirectHandler("/spaceapi/status.json", http.StatusFound))
 
 	log.Printf("Listening on %s...", addr)
 	log.Fatal(http.ListenAndServe(addr, nil))
 }
 
-func readCurrentState(fileName string) (*spaceapi.SpaceStatus, error) {
-	file, err := os.Open(fileName)
-	if err != nil {
-		return nil, fmt.Errorf("error opening file: %s", err)
-	}
-	defer file.Close()
-
-	var status spaceapi.SpaceStatus
-	if err := json.NewDecoder(file).Decode(&status); err != nil {
-		return nil, fmt.Errorf("error decoding state: %s", err)
-	}
-
-	return &status, nil
-}
-
-func handleReadStatus(status *spaceapi.SpaceStatus) http.Handler {
+func handleReadStatus(statusFunc func() spaceapi.SpaceStatus) http.Handler {
 	return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+		status := statusFunc()
+
 		if err := json.NewEncoder(w).Encode(status); err != nil {
 			http.Error(w, fmt.Sprintf("Error encoding JSON: %s", err), http.StatusInternalServerError)
 		}
 	})
 }
 
-func handleSetState(status *spaceapi.SpaceStatus) http.Handler {
+func handleSetState(storage *spaceapi.Storage) http.Handler {
 	return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
 		if r.Method != http.MethodPost {
 			http.Error(w, fmt.Sprintf("Invalid method: %s", r.Method), http.StatusMethodNotAllowed)
@@ -73,7 +59,11 @@ func handleSetState(status *spaceapi.SpaceStatus) http.Handler {
 			return
 		}
 
-		status.State = newState
+		storage.Modify(func(status *spaceapi.SpaceStatus) {
+			status.State = newState
+		})
+
+		status := storage.Status()
 
 		if err := json.NewEncoder(w).Encode(status); err != nil {
 			http.Error(w, fmt.Sprintf("Error encoding JSON: %s", err), http.StatusInternalServerError)

spaceapi.go

@@ -1,4 +1,4 @@
-package spaceapi
+package spaceapi // import "git.hacknology.de/projekte/spaceapi"
 
 type SpaceStatus struct {
 	APIVersion          string          `json:"api,omitempty"`

storage.go

@@ -0,0 +1,53 @@
+package spaceapi
+
+import (
+	"encoding/json"
+	"fmt"
+	"os"
+)
+
+type Listener func(status SpaceStatus)
+
+type Storage struct {
+	filePath   string
+	persistent bool
+	status     SpaceStatus
+}
+
+func Open(filePath string, persistent bool) (*Storage, error) {
+	status, err := readFile(filePath)
+	if err != nil {
+		return nil, fmt.Errorf("error reading status: %s", err)
+	}
+
+	return &Storage{
+		filePath:   filePath,
+		persistent: persistent,
+		status:     *status,
+	}, nil
+}
+
+func (s *Storage) Status() SpaceStatus {
+	return s.status
+}
+
+func (s *Storage) Modify(modifiers ...func(*SpaceStatus)) {
+	for _, m := range modifiers {
+		m(&s.status)
+	}
+}
+
+func readFile(fileName string) (*SpaceStatus, error) {
+	file, err := os.Open(fileName)
+	if err != nil {
+		return nil, fmt.Errorf("error opening file: %s", err)
+	}
+	defer file.Close()
+
+	var status SpaceStatus
+	if err := json.NewDecoder(file).Decode(&status); err != nil {
+		return nil, fmt.Errorf("error decoding state: %s", err)
+	}
+
+	return &status, nil
+}