/// <summary>
/// Inspects the data and mapping and loads all related entities from the API, that are referenced by custom use keys like Code and Name.
/// The purpose is to use the Ids of these entities in the constructed Entity objects that are being imported.
/// </summary>
private async Task <RelatedEntities> LoadRelatedEntities(IEnumerable <string[]> dataWithoutHeader, MappingInfo mapping, ImportErrors errors)
{
if (errors is null)
{
throw new ArgumentNullException(nameof(errors));
}
// Each set of foreign keys will result in an API query to retrieve the corresponding Ids for FK hydration
// So we group foreign keys by the target type, the target definition Id and the key property (e.g. Code or Name)
var queryInfos = new List <(Type navType, int?navDefId, PropertyDescriptor keyPropMeta, HashSet <object> keysSet)>();
foreach (var g in mapping.GetForeignKeys().Where(p => p.NotUsingIdAsKey)
.GroupBy(fk => (fk.TargetType, fk.TargetDefId, fk.KeyPropertyMetadata.Descriptor)))
{
var(navType, navDefId, keyPropDesc) = g.Key;
var keysSet = new HashSet <object>();
foreach (var fkMapping in g)
{
int rowNumber = 2;
foreach (var row in dataWithoutHeader)
{
string stringKey = row[fkMapping.Index];
if (string.IsNullOrEmpty(stringKey))
{
continue;
}
switch (fkMapping.KeyType)
{
case KeyType.String:
keysSet.Add(stringKey);
break;
case KeyType.Int:
if (int.TryParse(stringKey, out int intKey))
{
keysSet.Add(intKey);
}
else if (!errors.AddImportError(rowNumber, fkMapping.ColumnNumber, _localizer[$"Error_TheValue0IsNotAValidInteger", stringKey]))
{
// This means the validation errors are at maximum capacity, pointless to keep going.
return(null);
}
break;
default:
throw new InvalidOperationException("Bug: Only int and string Ids are supported.");
}
rowNumber++;
}
}
if (keysSet.Any())
{
// Actual API calls are delayed till the end in case there are any errors
queryInfos.Add((navType, navDefId, keyPropDesc, keysSet));
}
}
if (!errors.IsValid)
{
return(null);
}
var result = new RelatedEntities();
if (queryInfos.Any())
{
// Load all related entities in parallel
await Task.WhenAll(queryInfos.Select(async queryInfo =>
{
var(navType, navDefId, keyPropDesc, keysSet) = queryInfo; // Deconstruct the queryInfo
var keyPropName = keyPropDesc.Name;
var data = await _client.GetEntitiesByPropertyValues(
collection: navType.Name,
definitionId: navDefId,
propName: keyPropName,
values: keysSet,
cancellation: default);
/// <summary>
/// Takes an <see cref="IEnumerable{T}"/> of string arrays representing the raw data of the imported file.
/// Then using the specifications in the <see cref="MappingInfo"/> it translates this raw data into an
/// <see cref="IEnumerable{T}"/> of entities. Any problems will be added in the <see cref="ImportErrors"/> dictionary.
/// This function is the opposite of <see cref="DataComposer.Compose{TEntityForSave}"/>.
/// </summary>
public async Task <IEnumerable <TEntityForSave> > ParseAsync <TEntityForSave>(IEnumerable <string[]> dataWithoutHeader, MappingInfo mapping, ImportErrors errors)
where TEntityForSave : Entity
{
// Load related entities from API
var relatedEntities = await LoadRelatedEntities(dataWithoutHeader, mapping, errors);
if (!errors.IsValid)
{
return(null);
}
// Clear all cached entities and lists, and create the root list
mapping.ClearEntitiesAndLists();
mapping.List = new List <TEntityForSave>(); // This root list will contain the final result
// Set some values on the root mapping for for handling self referencing FKs
mapping.IsRoot = true;
int matchesIndex = 0;
foreach (var prop in mapping.SimpleProperties.OfType <ForeignKeyMappingInfo>().Where(p => p.IsSelfReferencing))
{
prop.EntityMetadataMatchesIndex = matchesIndex++;
}
int rowNumber = 2;
foreach (var dataRow in dataWithoutHeader) // Foreach row
{
bool keepGoing = ParseRow(dataRow, rowNumber, mapping, relatedEntities, errors, matchesIndex); // Recursive function
if (!keepGoing)
{
// This means the errors collection is full, no need to keep going
break;
}
rowNumber++;
}
// Grab the result from the root mapping
var result = mapping.List.Cast <TEntityForSave>();
// Hydrate self referencing FKs if any, these properties are not hydrated in ParseRow()
// Since they requires all the imported entities to be created and all their other
// properties already hydrated
HydrateSelfReferencingForeignKeys(result, mapping, errors);
// Return the result
return(result);
}