CSV Validator

.NET Core CSV text file validator. Enables the quick verification of column separated data files. Columns can be checked against multiple requirements for correctness.

This application is provided via a CLI and a NuGet package. Details for using both are provided below.

CLI Usage

The application is command line based, and has two arguments:

validate --file "input-datafile.csv" --with "configuration.json"

Configuration

To configure the verification a JSON file is used with the following format:

{
	"rowSeperator": "\r\n",
	"columnSeperator": ",",
	"hasHeaderRow": true,
	"columns": {
		"1": {
			"name": "ID",
			"isRequired": true,
			"unique": true
		},
		"2": {
			"name": "DOB",
			"pattern": "^\\d\\d\\d\\d-\\d\\d-\\d\\d$"
		},
		"3": {
			"name": "NOTES",
			"maxLength": "250"
		}
	}
}

The pattern property uses regular expressions but it is important to escape the characters else the application will fail when reading the configuration file.

rowSeperator can be any number of characters, rows can also be separated by characters and do not need the new line characters to be available in the input file.

columnSeperator can be one or more characters.

The columns require the number, which is the ordinal of the column in the input file, you do not need to specify all columns, only those that are to be validated.

Supported validation

{
    // validates the column has content
    "isRequired": true|false,
    // validates the content is unique in this column across the full file
    "unique": true|false,
    // validates a string against a regular expression
    "pattern": "regular expression string",
    // Maximum allowable length for a column
    "maxLength": "int",
    // Check if content is numerical
    "isNumeric": true|false
}

API Usage

CSV Validator is also available as a NuGet package, to enable in application validation of text files. The API conforms to netstandard 2.0.

Installation

dotnet add package csvvalidator

<ItemGroup>
  <PackageReference Include="csvvalidator" Version="1.0.1" />
</ItemGroup>

Usage

Validator validator = Validator.FromJson(config);
RowValidationError[] errors = validator.Validate(inputStream);

Dealing with validation errors.

Errors are reported heirarchicly, by row and then columns.

foreach(RowValidationError current in errors) 
{
	// row errors provides details of the row number and the content
	Console.WriteLine($"Errors in row[{current.Row}]: {current.Content}");
	foreach(ValidationError error in current.Errors)
	{
		// all errors then that occur on that row are reported in the error collection
		Console.WriteLine($"{error.Message} at {error.AtCharacter}");
	}
}