---
title: "PreFlightCheck"
slug: "preflightcheck"
updated: 2023-11-13T14:24:43Z
published: 2023-11-13T14:24:44Z
canonical: "docs.datajet.app/preflightcheck"
---

> ## Documentation Index
> Fetch the complete documentation index at: https://docs.datajet.app/llms.txt
> Use this file to discover all available pages before exploring further.

# PreFlightCheck

Verifies that files and directories exist, and whether files can be opened. Used at the start of a script to verify inputs.

| Key | Value(s) | Description |
| --- | --- | --- |
| method | "PreFlightCheck" | Tests to see whether specified files and directories exist and can be opened/accessed |
| project | "projectname" | Current Project name |
| filesExist[] | [ "file1", "file2" ] | Optional. If any file in the list does not exist, method will fail |
| directoriesExist[] | [ "directory1", "directory2" ] | Optional. If any directory in the list does not exist, method will fail |
| filesOpenable[] | [ "file1", "file2" ] | Optional. If any file in the list cannot be opened, method will fail. |
| allowEmptyFiles | true/false | Optional. Default = false. If true, an empty file will not cause the method to raise an error |

```json
{
  "method": "PreFlightCheck",
  "directoriesExist": [
    "%DATAPATH%RegressionTest/SalesDirectory"
  ],
  "filesExist": [
    "%DATAPATH%RegressionTest/d3-product.dat",
    "%DATAPATH%RegressionTest/d3-customer.dat"
  ],
  "filesOpenable": [
    "%DATAPATH%RegressionTest/FieldPropertiesWorkbook.xlsx"
  ],
  "project": "RegressionDB"
}
```