implemented mongo gridFS for file upload

pkg/filestore/errors.go

@@ -0,0 +1,89 @@
+package filestore
+
+import "errors"
+
+// Error codes for file store operations
+const (
+	ErrCodeNotFound       = "FILE_NOT_FOUND"
+	ErrCodeUploadFailed   = "UPLOAD_FAILED"
+	ErrCodeDownloadFailed = "DOWNLOAD_FAILED"
+	ErrCodeDeleteFailed   = "DELETE_FAILED"
+	ErrCodeInvalidInput   = "INVALID_INPUT"
+	ErrCodeFileTooLarge   = "FILE_TOO_LARGE"
+	ErrCodeUnsupported    = "UNSUPPORTED_FILE_TYPE"
+	ErrCodeDuplicate      = "DUPLICATE_FILE"
+	ErrCodeAccessDenied   = "ACCESS_DENIED"
+)
+
+// FileStoreError represents a file store operation error
+type FileStoreError struct {
+	Code    string
+	Message string
+	Cause   error
+}
+
+// Error implements the error interface
+func (e *FileStoreError) Error() string {
+	if e.Cause != nil {
+		return e.Message + ": " + e.Cause.Error()
+	}
+	return e.Message
+}
+
+// NewError creates a new FileStoreError
+func NewError(code, message string) *FileStoreError {
+	return &FileStoreError{
+		Code:    code,
+		Message: message,
+		Cause:   nil,
+	}
+}
+
+// NewErrorWithCause creates a new FileStoreError with an underlying cause
+func NewErrorWithCause(code, message string, cause error) *FileStoreError {
+	return &FileStoreError{
+		Code:    code,
+		Message: message,
+		Cause:   cause,
+	}
+}
+
+// Predefined errors
+var (
+	ErrFileNotFound    = NewError(ErrCodeNotFound, "file not found")
+	ErrUploadFailed    = NewError(ErrCodeUploadFailed, "file upload failed")
+	ErrDownloadFailed  = NewError(ErrCodeDownloadFailed, "file download failed")
+	ErrDeleteFailed    = NewError(ErrCodeDeleteFailed, "file deletion failed")
+	ErrInvalidInput    = NewError(ErrCodeInvalidInput, "invalid input")
+	ErrFileTooLarge    = NewError(ErrCodeFileTooLarge, "file size exceeds maximum limit")
+	ErrUnsupportedType = NewError(ErrCodeUnsupported, "unsupported file type")
+	ErrDuplicateFile   = NewError(ErrCodeDuplicate, "file already exists")
+	ErrAccessDenied    = NewError(ErrCodeAccessDenied, "access denied")
+)
+
+// IsNotFound checks if an error is a not found error
+func IsNotFound(err error) bool {
+	var fse *FileStoreError
+	if errors.As(err, &fse) {
+		return fse.Code == ErrCodeNotFound
+	}
+	return false
+}
+
+// IsFileTooLarge checks if an error is a file too large error
+func IsFileTooLarge(err error) bool {
+	var fse *FileStoreError
+	if errors.As(err, &fse) {
+		return fse.Code == ErrCodeFileTooLarge
+	}
+	return false
+}
+
+// IsUnsupportedType checks if an error is an unsupported type error
+func IsUnsupportedType(err error) bool {
+	var fse *FileStoreError
+	if errors.As(err, &fse) {
+		return fse.Code == ErrCodeUnsupported
+	}
+	return false
+}