/// <summary>
/// Gets an EF query and returns its hashed key to store in the cache.
/// </summary>
/// <param name="query">The EF query.</param>
/// <param name="expression">An expression tree that represents a LINQ query.</param>
/// <param name="saltKey">If you think the computed hash of the query is not enough, set this value.</param>
/// <returns>Information of the computed key of the input LINQ query.</returns>
public EFCacheKey GetEFCacheKey(IQueryable query, Expression expression, string saltKey = "")
{
var queryCompiler = (QueryCompiler)_queryCompilerField.GetValue(query.Provider);
var(expressionKeyHash, modifiedExpression) = getExpressionKeyHash(queryCompiler, _cacheKeyHashProvider, expression);
var cachedKey = _keysCacheManager.Get <EFCacheKey>(expressionKeyHash);
if (cachedKey != null)
{
return(cachedKey);
}
var expressionPrinter = new ExpressionPrinter();
var sql = expressionPrinter.PrintDebug(modifiedExpression);
var expressionVisitorResult = EFQueryExpressionVisitor.GetDebugView(expression);
var key = $"{sql};{expressionVisitorResult.DebugView};{saltKey}";
var keyHash = _cacheKeyHashProvider.ComputeHash(key);
var cacheKey = new EFCacheKey
{
Key = key,
KeyHash = keyHash,
CacheDependencies = expressionVisitorResult.Types
};
setCache(expressionKeyHash, cacheKey);
return(cacheKey);
}
/// <summary>
/// Write out the given AST
/// </summary>
public static EFQueryDebugView GetDebugView(Expression node)
{
using (var writer = new StringWriter(CultureInfo.CurrentCulture))
{
var efQueryExpressionVisitor = new EFQueryExpressionVisitor(writer);
efQueryExpressionVisitor.writeTo(node);
var types = efQueryExpressionVisitor._types;
return(new EFQueryDebugView {
DebugView = writer.ToString(), Types = types
});
}
}