Data providers

A data provider reads data from a data source and returns it as an IDataReader. CMSImport uses that reader to import the records.

A data provider has two classes:

• the provider, which reads the data, and
• an options class, which defines the UI where the user selects the data source.

The example on this page reads an RSS feed. It is the same code as the CMSImport.DataProviders.RSS package.

Provider

Derive from DataProvider and add the [DataProvider] attribute.

Member	Description
GetData	Returns an IDataReader for the options the user entered. onlyFirstRow is true when CMSImport only needs the column names.
Validate	Validates the options and returns a ValidationResult with error messages.
GetDataProviderOptions	Returns a new instance of your options class.
SupportRecursiveImports	Optional. Return false when the data source can't be used for recursive imports.

using System;
using System.Data;
using CMSImport.Core.Helpers;
using CMSImport.Core.Models.Validation;
using CMSImport.Core.Providers;
using CMSImport.Core.Providers.DataProviders;

[DataProvider(Alias = "Rss File", Name = "RSS File", ContentType = "Content",
    Title = "RSS Demo", Intro = "Demo provider for RSS feeds")]
public class RssFeedDataProvider : DataProvider
{
    private readonly IFileOrUrlModelHelper _fileOrUrlModelHelper;

    public RssFeedDataProvider(IFileOrUrlModelHelper fileOrUrlModelHelper)
    {
        _fileOrUrlModelHelper = fileOrUrlModelHelper;
    }

    public override IDataReader GetData(IProviderOptions dataProviderOptions, bool onlyFirstRow = false)
    {
        var options = dataProviderOptions as RssFeedDataProviderOptions;
        var xml = _fileOrUrlModelHelper.GetDataFromFileOrUrl(options.Datasource);
        return XmlDataHelper.XmlToDataReader(xml, false, "//item");
    }

    public override ValidationResult Validate(IProviderOptions providerOptions)
    {
        var result = new ValidationResult();
        try
        {
            using var dataReader = GetData(providerOptions);
            if (!dataReader.Read())
            {
                result.ErrorMessages.Add("No data in file");
            }
        }
        catch (Exception ex)
        {
            result.ErrorMessages.Add($"Error validating the RSS feed: {ex.Message}");
        }
        return result;
    }

    public override IProviderOptions GetDataProviderOptions() => new RssFeedDataProviderOptions();

    public override bool SupportRecursiveImports => false;
}

Options class

Implement IProviderOptions:

• Alias links the options to the provider. Use the same alias as in the [DataProvider] attribute.
• RenderField lets you hide fields. fieldAlias is the property name in lowercase.
• Decorate each property with a UI field attribute. Here [DatasourcePicker] lets the user upload a file or enter a URL, and [FileModelValidation] checks that they did.

using System.Collections.Generic;
using CMSImport.Common.ValueConverters;
using CMSImport.Core.Attributes.EditorFields;
using CMSImport.Core.Attributes.ValidationAttributes;
using CMSImport.Core.Models.ProviderModels;
using CMSImport.Core.Providers;

public class RssFeedDataProviderOptions : IProviderOptions
{
    [DatasourcePicker(Name = "Select RSS file", FieldValueConverter = typeof(FileOrUrlPickerValueConverter))]
    [FileModelValidation]
    public FileOrUrlPickerModel Datasource { get; set; } = new();

    public string Alias => "Rss File";

    public bool RenderField(string fieldAlias) => true;

    public List<AliasValue> PropertyValues { get; set; } = [];
}

Note

FileOrUrlPickerValueConverter lives in CMSImport.Common. Install the CMSImport.Common package (or the full CMSImport package) when you use it.