feat: add books APIs

pkg/response/response.go

@@ -0,0 +1,67 @@
+package response
+
+import (
+	"encoding/json"
+	"net/http"
+)
+
+// Envelope wraps API responses in a consistent structure.
+type Envelope struct {
+	Success bool        `json:"success"`
+	Data    interface{} `json:"data,omitempty"`
+	Error   *ErrorBody  `json:"error,omitempty"`
+	Meta    *Meta       `json:"meta,omitempty"`
+}
+
+// ErrorBody represents an error response.
+type ErrorBody struct {
+	Code    int    `json:"code"`
+	Message string `json:"message"`
+}
+
+// Meta holds pagination and other metadata.
+type Meta struct {
+	Page       int   `json:"page,omitempty"`
+	Limit      int   `json:"limit,omitempty"`
+	Total      int64 `json:"total,omitempty"`
+	TotalPages int   `json:"total_pages,omitempty"`
+}
+
+// JSON sends a success response with the given data.
+func JSON(w http.ResponseWriter, status int, data interface{}) {
+	w.Header().Set("Content-Type", "application/json")
+	w.WriteHeader(status)
+	json.NewEncoder(w).Encode(Envelope{
+		Success: true,
+		Data:    data,
+	})
+}
+
+// JSONWithMeta sends a success response with data and pagination metadata.
+func JSONWithMeta(w http.ResponseWriter, status int, data interface{}, meta *Meta) {
+	w.Header().Set("Content-Type", "application/json")
+	w.WriteHeader(status)
+	json.NewEncoder(w).Encode(Envelope{
+		Success: true,
+		Data:    data,
+		Meta:    meta,
+	})
+}
+
+// Error sends an error response.
+func Error(w http.ResponseWriter, status int, message string) {
+	w.Header().Set("Content-Type", "application/json")
+	w.WriteHeader(status)
+	json.NewEncoder(w).Encode(Envelope{
+		Success: false,
+		Error: &ErrorBody{
+			Code:    status,
+			Message: message,
+		},
+	})
+}
+
+// NoContent sends a 204 No Content response.
+func NoContent(w http.ResponseWriter) {
+	w.WriteHeader(http.StatusNoContent)
+}