How to write regular expression to get parts from connection string?

Question

how to write regular expression to extract content of metadata, provider, provider connection string from

 metadata=res://*/ent.csdl|res://*/ent.ssdl|res://*/ent.msl;provider=System.Data.SqlClient;provider connection string="Data Source=1.1.1.1;Initial Catalog={0};Persist Security Info=True;User ID=user;Password=pass;MultipleActiveResultSets=True"

I mean, I want to get

Metadata: res://*/ent.csdl|res://*/ent.ssdl|res://*/ent.msl

Provider: System.Data.SqlClient

provider connection string: Data Source=1.1.1.1;Initial Catalog={0};Persist Security Info=True;User ID=user;Password=pass;MultipleActiveResultSets=True

Answer 1

Without assuming any specific order of the ConnString:

var connString = @"metadata=res://*/ent.csdl|res://*/ent.ssdl|res://*/ent.msl;provider=System.Data.SqlClient;provider connection string=""Data Source=1.1.1.1;Initial Catalog={0};Persist Security Info=True;User ID=user;Password=pass;MultipleActiveResultSets=True""";
Regex metaRegex = new Regex(@"metadata=(?<metadata>[^;]+)");
Regex connRegex = new Regex(@"provider\sconnection\sstring=""(?<conn>[^""]+)");
Regex providerRegex = new Regex(@"provider=(?<provider>[^;]+)");
Console.WriteLine("MetaData: " + metaRegex.Match(connString).Groups["metadata"]);
Console.WriteLine("Connection String: " + connRegex.Match(connString).Groups["conn"]);
Console.WriteLine("Provider: " + providerRegex.Match(connString).Groups["provider"]);

Answer 2

A regex such as:

^(res:[^;]+);provider=([^;]+);provider\sconnection\sstring=\"(.+)\"$

Gives you 3 capture groups, providing the parts you need.

Live example: http://rextester.com/rundotnet?code=JRGSO74516

Answer 3

You can use named capture groups to define patterns for each category, which is supported by .Net RegEx matching. See here for an explanation on named capture groups.