I've implemented a search-query. It replaces special chars with "normalized" ones. I've apply this rule on different fields. Actually, the query looks very ugly and is full of DRY-violations.
But refacotring this, doesn't seem to be an easy thing (for me). Of course, I just tried to refactor the whole Replace-Stuff into a separate method, but this resulted in an error like
LINQ to Entities does not recognize the method 'System.String Help(System.String)' method, and this method cannot be translated into a store expressio...
The code below shows a part of the query, there are even more statements like this in it. If somebody would have an idea, to make this nicer, it would be great!
qry = qry.Where(guest =>
(guest.FirstName
.Replace("ü", "u").Replace("ue", "u").Replace("û", "u").Replace("ù", "u").Replace("ú", "u")
.Replace("ä", "a").Replace("ae", "a").Replace("â", "a").Replace("à", "a").Replace("á", "a")
.Replace("ë", "e").Replace("ê", "e").Replace("è", "e").Replace("é", "e")
.Replace("ö", "o").Replace("oe", "o").Replace("ô", "o").Replace("ò", "o").Replace("ó", "o")
.Replace("ï", "i").Replace("ì", "i").Replace("ì", "i").Replace("í", "i")
.Replace("ç", "c")
.Replace(".", "").Replace("-", "").Replace("_", "").Replace("´", "").Replace("'", "").Replace("\"", "")
.Replace("(", "").Replace(")", "").Replace("[", "").Replace("]", "").Replace("{", "").Replace("}", "")
.Replace("$", "").Replace("+", "").Replace("*", "").Replace("@", "")
.Replace("|", "").Replace("\\", "").Replace("/", "").Replace("<", "").Replace(">", "")
.Replace(".", "").Replace(",", "").Replace(";", "").Replace(":", "")
.Replace("=", "").Replace("%", "").Replace("^", "").Replace("?", "").Replace("!", "")
.StartsWith(firstName)
&& (guest.LastName
.Replace("ü", "u").Replace("ue", "u").Replace("û", "u").Replace("ù", "u").Replace("ú", "u")
.Replace("ä", "a").Replace("ae", "a").Replace("â", "a").Replace("à", "a").Replace("á", "a")
.Replace("ë", "e").Replace("ê", "e").Replace("è", "e").Replace("é", "e")
.Replace("ö", "o").Replace("oe", "o").Replace("ô", "o").Replace("ò", "o").Replace("ó", "o")
.Replace("ï", "i").Replace("ì", "i").Replace("ì", "i").Replace("í", "i")
.Replace("ç", "c")
.Replace(".", "").Replace("-", "").Replace("_", "").Replace("´", "").Replace("'", "").Replace("\"", "")
.Replace("(", "").Replace(")", "").Replace("[", "").Replace("]", "").Replace("{", "").Replace("}", "")
.Replace("$", "").Replace("+", "").Replace("*", "").Replace("@", "")
.Replace("|", "").Replace("\\", "").Replace("/", "").Replace("<", "").Replace(">", "")
.Replace(".", "").Replace(",", "").Replace(";", "").Replace(":", "")
.Replace("=", "").Replace("%", "").Replace("^", "").Replace("?", "").Replace("!", "")
.StartsWith(lastName)
||
guest.LastName
.Replace("ü", "u").Replace("ue", "u").Replace("û", "u").Replace("ù", "u").Replace("ú", "u")
.Replace("ä", "a").Replace("ae", "a").Replace("â", "a").Replace("à", "a").Replace("á", "a")
.Replace("ë", "e").Replace("ê", "e").Replace("è", "e").Replace("é", "e")
.Replace("ö", "o").Replace("oe", "o").Replace("ô", "o").Replace("ò", "o").Replace("ó", "o")
.Replace("ï", "i").Replace("ì", "i").Replace("ì", "i").Replace("í", "i")
.Replace("ç", "c")
.Replace(".", "").Replace("-", "").Replace("_", "").Replace("´", "").Replace("'", "").Replace("\"", "")
.Replace("(", "").Replace(")", "").Replace("[", "").Replace("]", "").Replace("{", "").Replace("}", "")
.Replace("$", "").Replace("+", "").Replace("*", "").Replace("@", "")
.Replace("|", "").Replace("\\", "").Replace("/", "").Replace("<", "").Replace(">", "")
.Replace(".", "").Replace(",", "").Replace(";", "").Replace(":", "")
.Replace("=", "").Replace("%", "").Replace("^", "").Replace("?", "").Replace("!", "")
.Contains(" " + lastName)
||
guest.LastName.Replace(" ", "")
.Replace("ü", "u").Replace("ue", "u").Replace("û", "u").Replace("ù", "u").Replace("ú", "u")
.Replace("ä", "a").Replace("ae", "a").Replace("â", "a").Replace("à", "a").Replace("á", "a")
.Replace("ë", "e").Replace("ê", "e").Replace("è", "e").Replace("é", "e")
.Replace("ö", "o").Replace("oe", "o").Replace("ô", "o").Replace("ò", "o").Replace("ó", "o")
.Replace("ï", "i").Replace("ì", "i").Replace("ì", "i").Replace("í", "i")
.Replace("ç", "c")
.Replace(".", "").Replace("-", "").Replace("_", "").Replace("´", "").Replace("'", "").Replace("\"", "")
.Replace("(", "").Replace(")", "").Replace("[", "").Replace("]", "").Replace("{", "").Replace("}", "")
.Replace("$", "").Replace("+", "").Replace("*", "").Replace("@", "")
.Replace("|", "").Replace("\\", "").Replace("/", "").Replace("<", "").Replace(">", "")
.Replace(".", "").Replace(",", "").Replace(";", "").Replace(":", "")
.Replace("=", "").Replace("%", "").Replace("^", "").Replace("?", "").Replace("!", "")
.StartsWith(lastName))
) || (
guest.FirstName
.Replace("ü", "u").Replace("ue", "u").Replace("û", "u").Replace("ù", "u").Replace("ú", "u")
.Replace("ä", "a").Replace("ae", "a").Replace("â", "a").Replace("à", "a").Replace("á", "a")
.Replace("ë", "e").Replace("ê", "e").Replace("è", "e").Replace("é", "e")
.Replace("ö", "o").Replace("oe", "o").Replace("ô", "o").Replace("ò", "o").Replace("ó", "o")
.Replace("ï", "i").Replace("ì", "i").Replace("ì", "i").Replace("í", "i")
.Replace("ç", "c")
.StartsWith(lastName)
&& (guest.LastName
.Replace("ü", "u").Replace("ue", "u").Replace("û", "u").Replace("ù", "u").Replace("ú", "u")
.Replace("ä", "a").Replace("ae", "a").Replace("â", "a").Replace("à", "a").Replace("á", "a")
.Replace("ë", "e").Replace("ê", "e").Replace("è", "e").Replace("é", "e")
.Replace("ö", "o").Replace("oe", "o").Replace("ô", "o").Replace("ò", "o").Replace("ó", "o")
.Replace("ï", "i").Replace("ì", "i").Replace("ì", "i").Replace("í", "i")
.Replace("ç", "c")
.Replace(".", "").Replace("-", "").Replace("_", "").Replace("´", "").Replace("'", "").Replace("\"", "")
.Replace("(", "").Replace(")", "").Replace("[", "").Replace("]", "").Replace("{", "").Replace("}", "")
.Replace("$", "").Replace("+", "").Replace("*", "").Replace("@", "")
.Replace("|", "").Replace("\\", "").Replace("/", "").Replace("<", "").Replace(">", "")
.Replace(".", "").Replace(",", "").Replace(";", "").Replace(":", "")
.Replace("=", "").Replace("%", "").Replace("^", "").Replace("?", "").Replace("!", "")
.StartsWith(firstName)
||
guest.LastName
.Replace("ü", "u").Replace("ue", "u").Replace("û", "u").Replace("ù", "u").Replace("ú", "u")
.Replace("ä", "a").Replace("ae", "a").Replace("â", "a").Replace("à", "a").Replace("á", "a")
.Replace("ë", "e").Replace("ê", "e").Replace("è", "e").Replace("é", "e")
.Replace("ö", "o").Replace("oe", "o").Replace("ô", "o").Replace("ò", "o").Replace("ó", "o")
.Replace("ï", "i").Replace("ì", "i").Replace("ì", "i").Replace("í", "i")
.Replace("ç", "c")
.Replace(".", "").Replace("-", "").Replace("_", "").Replace("´", "").Replace("'", "").Replace("\"", "")
.Replace("(", "").Replace(")", "").Replace("[", "").Replace("]", "").Replace("{", "").Replace("}", "")
.Replace("$", "").Replace("+", "").Replace("*", "").Replace("@", "")
.Replace("|", "").Replace("\\", "").Replace("/", "").Replace("<", "").Replace(">", "")
.Replace(".", "").Replace(",", "").Replace(";", "").Replace(":", "")
.Replace("=", "").Replace("%", "").Replace("^", "").Replace("?", "").Replace("!", "")
.Contains(" " + firstName)
||
guest.LastName.Replace(" ", "")
.Replace("ü", "u").Replace("ue", "u").Replace("û", "u").Replace("ù", "u").Replace("ú", "u")
.Replace("ä", "a").Replace("ae", "a").Replace("â", "a").Replace("à", "a").Replace("á", "a")
.Replace("ë", "e").Replace("ê", "e").Replace("è", "e").Replace("é", "e")
.Replace("ö", "o").Replace("oe", "o").Replace("ô", "o").Replace("ò", "o").Replace("ó", "o")
.Replace("ï", "i").Replace("ì", "i").Replace("ì", "i").Replace("í", "i")
.Replace("ç", "c")
.Replace(".", "").Replace("-", "").Replace("_", "").Replace("´", "").Replace("'", "").Replace("\"", "")
.Replace("(", "").Replace(")", "").Replace("[", "").Replace("]", "").Replace("{", "").Replace("}", "")
.Replace("$", "").Replace("+", "").Replace("*", "").Replace("@", "")
.Replace("|", "").Replace("\\", "").Replace("/", "").Replace("<", "").Replace(">", "")
.Replace(".", "").Replace(",", "").Replace(";", "").Replace(":", "")
.Replace("=", "").Replace("%", "").Replace("^", "").Replace("?", "").Replace("!", "")
.StartsWith(firstName))
));
You can indeed refactor the code into another function that returns an expression tree (as Jon stated).
I've put together a solution for you, although it is a little lengthy. Unfortunately working with expressions is pretty complicated, I do hope you find this useful though.
Note: to make this solution work you'll need to also use LinqKit (it's very useful when you're using LINQ with an ORM)
I'll start with how you use the code, and then show you the methods that make it work.
I created a function called TestCleanString. You need to give it a selector to select the property you want to test, and you also need to give it a predicate to test the string with.
For example; here we want to test the FirstName property, and we want to test if it starts with firstName. It will select the FirstName property, then clean it using your cleaning rules, and then test the result against the predicate.
TestCleanString<Guest>(g => g.FirstName, s => s.StartsWith(firstName));
Here it is in action:
//make an expression tree to check the first name
var firstnameOk = TestCleanString<Guest>(g => g.FirstName, s => s.StartsWith(firstName));
//make an expression tree to check the last name
var lastnameOk = TestCleanString<Guest>(g => g.LastName, s => s.StartsWith(lastName));
//make your additional filter expressions here ...
//...
//combine the expression trees together using the "And" and "Or" methods from LinqKit
var filter = firstnameOk.And(lastnameOk);
//pass the filter into the where method
qry = qry.Where(filter);
I placed your string cleaning code into the following function that returns an expression tree.
//returns an expression that will clean the string
private static Expression<Func<string, string>> CleanString()
{
return s => s.Replace("ü", "u").Replace("ue", "u").Replace("û", "u").Replace("ù", "u").Replace("ú", "u")
.Replace("ä", "a").Replace("ae", "a").Replace("â", "a").Replace("à", "a").Replace("á", "a")
.Replace("ë", "e").Replace("ê", "e").Replace("è", "e").Replace("é", "e")
.Replace("ö", "o").Replace("oe", "o").Replace("ô", "o").Replace("ò", "o").Replace("ó", "o")
.Replace("ï", "i").Replace("ì", "i").Replace("ì", "i").Replace("í", "i")
.Replace("ç", "c")
.Replace(".", "").Replace("-", "").Replace("_", "").Replace("´", "").Replace("'", "").Replace("\"", "")
.Replace("(", "").Replace(")", "").Replace("[", "").Replace("]", "").Replace("{", "").Replace("}", "")
.Replace("$", "").Replace("+", "").Replace("*", "").Replace("@", "")
.Replace("|", "").Replace("\\", "").Replace("/", "").Replace("<", "").Replace(">", "")
.Replace(".", "").Replace(",", "").Replace(";", "").Replace(":", "")
.Replace("=", "").Replace("%", "").Replace("^", "").Replace("?", "").Replace("!", "");
}
Lastly, lets look at the TestCleanString function. It builds an expression tree that performs the following 3 steps; select the property that you want to test, clean the resulting string, test the string against the specified conditional expression.
public static Expression<Func<TElement, bool>> TestCleanString<TElement>(Expression<Func<TElement, string>> stringSelector, Expression<Func<string, bool>> conditionalExpression)
{
//declare the parameter: e =>
var param = new[] { Expression.Parameter(typeof(TElement), "e") };
//pass the parameter into the selector to get the string property
var invokedStringSelector = Expression.Invoke(stringSelector, param.Cast<Expression>());
//pass the string property to the clean expression
var invokedCleanString = Expression.Invoke(CleanString(), invokedStringSelector.Expand());
//pass the cleaned string to the conditional expression
var invokedConditionalExpression = Expression.Invoke(conditionalExpression, invokedCleanString.Expand());
//rebuild the expression tree so the provider can understand it
return Expression.Lambda<Func<TElement, bool>>(invokedConditionalExpression.Expand(), param);
}
Incase you're interested, it generates SQL that will look a bit like this (i ran it against my own model so the names are different):
SELECT
1 AS [C1],
[Extent1].[EmailRecipientId] AS [EmailRecipientId],
[Extent1].[Address] AS [Address],
[Extent1].[SentOn] AS [SentOn],
[Extent1].[FailedOn] AS [FailedOn],
[Extent1].[FailReason] AS [FailReason],
[Extent1].[IsTo] AS [IsTo],
[Extent1].[IsCC] AS [IsCC],
[Extent1].[IsBCC] AS [IsBCC],
[Extent1].[EmailId] AS [EmailId]
FROM [dbo].[EmailRecipients] AS [Extent1]
INNER JOIN [dbo].[Emails] AS [Extent2] ON [Extent1].[EmailId] = [Extent2].[EmailId]
WHERE ( CAST(LEN(REPLACE(REPLACE(REPLACE(REPLACE(REPLACE(REPLACE(REPLACE(REPLACE(REPLACE(REPLACE(REPLACE(REPLACE(REPLACE(REPLACE(REPLACE(REPLACE(REPLACE(REPLACE(REPLACE(REPLACE(REPLACE(REPLACE(REPLACE(REPLACE(REPLACE(REPLACE(REPLACE(REPLACE(REPLACE(REPLACE(REPLACE(REPLACE(REPLACE(REPLACE(REPLACE(REPLACE(REPLACE(REPLACE(REPLACE(REPLACE(REPLACE(REPLACE(REPLACE(REPLACE(REPLACE(REPLACE(REPLACE(REPLACE(REPLACE(REPLACE(REPLACE(REPLACE(REPLACE(REPLACE([Extent2].[Subject], N'ü', N'u'), N'ue', N'u'), N'û', N'u'), N'ù', N'u'), N'ú', N'u'), N'ä', N'a'), N'ae', N'a'), N'â', N'a'), N'à', N'a'), N'á', N'a'), N'ë', N'e'), N'ê', N'e'), N'è', N'e'), N'é', N'e'), N'ö', N'o'), N'oe', N'o'), N'ô', N'o'), N'ò', N'o'), N'ó', N'o'), N'ï', N'i'), N'ì', N'i'), N'ì', N'i'), N'í', N'i'), N'ç', N'c'), N'.', N''), N'-', N''), N'_', N''), N'´', N''), N'''', N''), N'"', N''), N'(', N''), N')', N''), N'[', N''), N']', N''), N'{', N''), N'}', N''), N'$', N''), N'+', N''), N'*', N''), N'@', N''), N'|', N''), N'\', N''), N'/', N''), N'<', N''), N'>', N''), N'.', N''), N',', N''), N';', N''), N':', N''), N'=', N''), N'%', N''), N'^', N''), N'?', N''), N'!', N'')) AS int)) > 0