Check the integrity of a .env file before loading environment variables

Validates a .env file to ensure it is properly formatted for loading environment variables.

Usage

check_env_file(env_file = ".env", warning = TRUE)

Arguments

env_file

Path to the .env file (default: ".env")

warning

Logical; if TRUE, prints warnings for errors (default: TRUE)

Value

Logical: TRUE if valid, FALSE otherwise

Details

The function performs the following checks:

• Verifies file exists and is readable

• Confirms .env extension

• Ensures file is not empty

• Checks for at least one valid variable definition

• Validates non-comment, non-empty lines follow KEY=VALUE format (allowing optional whitespace around KEY, '=', and VALUE)

• Ensures variable names start with letter/underscore, followed by letters/digits/underscores

• Checks for duplicate variable names (case-sensitive)

• Ignores comment lines (starting with #) and empty lines

• Validates no unclosed quotes in values

• Checks for unquoted special characters in values

Author

Ahmed El-Gabbas

Examples

# Save a valid .env file to temp file
valid_env <- fs::file_temp(ext = ".env")
writeLines(
  c("DB_HOST=localhost", "DB_PORT=5432", "# Comment", "API_KEY='abc123'"),
  valid_env)
check_env_file(valid_env)  # Returns TRUE
#> [1] TRUE

# Invalid .env file
invalid_env <- fs::file_temp(ext = ".env")

writeLines(
  c(
   "DB_HOST=localhost", "INVALID KEY=value",
   "DB_HOST=duplicate"),
 invalid_env)
check_env_file(invalid_env)  # Returns FALSE
#> Warning: Invalid variable definition(s): INVALID KEY=value
#> Warning: Duplicate variable names: DB_HOST
#> [1] FALSE