Develop Reference

Get connection string value from Microsoft.AspNetCore.TestHost.TestServer

I have a test project, i need to get the connection string value in a test class
public class EmplyeesScenarios
{
private readonly TestServer _testServer;
private readonly AppDbContext _testService;
public EmplyeesScenarios()
{
_testServer = TestServerFactory.CreateServer<TestsStartup>();
var dbOption = new DbContextOptionsBuilder<AppDbContext>()
.UseSqlServer("//here i need to put the same connection string of _testServer")
.Options;
_testService = new AppDbContext(dbOption);
}
}

You can use the service collection on your test host. For example:
var config = _testServer.Host.Services.GetRequiredService<IConfigurationRoot>();
var connectionString = config.GetConnectionString("Foo");
However, you should actually be using this for all your services, so instead of trying to new up your context at all, just do:
var context = _testServer.Host.Services.GetRequiredService<AppDbContext>();
No connection string needed.

Assuming that your test server is set up properly, you should just resolve your database context from the server instance directly. Like this:
_testServer = TestServerFactory.CreateServer<TestsStartup>();
// create service scope and retrieve database context
using (var scope = _testServer.Host.Services.CreateScope())
{
var db = scope.ServiceProvider.GetService<AppDbContext>();
// ensure that the db is created for example
await db.Database.EnsureCreatedAsync();
// add test fixtures or whatever
}
Technically, you could also resolve the configuration from the test host and the read the connection string out of it but since you are doing an integration test, you should actually test the full integration and not deviate from the existing setup by creating your database context manually.

Modify connectionString in WCF Data Services 5.6

I'm using Oracle DataAccess (the last one), I have many Database users inside it. So, I want to create the connectionString in my client application (WPF) and pass it to the server. I'm doing the following in my server:
protected override POSContext CreateDataSource()
{
HttpRequest req = HttpContext.Current.Request;
if (req.Headers != null && Array.FindIndex(req.Headers.AllKeys, c=>c.Equals("db", StringComparison.OrdinalIgnoreCase)) > 0)
{
string database = req.Headers["db"];
string user = req.Headers["user"];
string pass = req.Headers["pass"];
StringBuilder conexion = new StringBuilder();
conexion.Append("DATA SOURCE=");
conexion.Append(database);
conexion.Append(";USER ID=");
conexion.Append(user);
conexion.Append(";PASSWORD=");
conexion.Append(pass);
if (!string.IsNullOrEmpty(conexion.ToString()))
return new POSContext(conexion.ToString());
}
return null;//new POSContext();
}
In the client, I have the following code:
var context = new POS.DataServices.POSContext(new Uri(Storage.Current.UrlService)); // Something like this http://localhost/POService.svc
context.BuildingRequest += (s, args) => //Or SendingRequest2 produces the same result
{
args.Headers.Add("db", Storage.Current.Configuraciones.DB);
args.Headers.Add("user", Storage.Current.Configuraciones.UserName);
args.Headers.Add("pass", Storage.Current.Configuraciones.Password);
};
MessageBox.Show(proxy.POS_CIUDAD.ToList().FirstOrDefault().CIU_DESC); //Alert the city name
When I debug my application I have an error (request error). My client code is trying to Show the message first and then go to the BuildingRequest. How can I pass the connectionString before Entity calls?

CreateDataSource is called once when the service starts, that's why you get the error there.
I think you can try the following:
Add a connection string a property on POSContext, and give POSContext a parameterless constructor. That is the connection string could be set later. And maybe you need to make sure the connection is only set when the connection string is ready.
Override OnStartProcessingRequest method, and change the connection string on CurrentDataSource (POSContext class)

How to use a dynamic connection string using a Model First approach but still use the data model in the EDMX?

I have created an EDMX using EF 5 with the Model First approach, i.e. I started with a blank designer and modeled my entities. Now I want to be able to use this model defined in the EDMX but supply runtime SQL Server connection strings without modyfing the config file.
I know how to pass a connection string to the DbContext but the issue is locating the metadata for the mappings within the assembly.
For example, my EDMX has this connection string in the app.config
<add name="MesSystemEntities" connectionString="metadata=res://*/Data.DataContext.EntityFramework.MesSystem.csdl|res://*/Data.DataContext.EntityFramework.MesSystem.ssdl|res://*/Data.DataContext.EntityFramework.MesSystem.msl;provider=System.Data.SqlClient;provider connection string="data source=MyMachine;initial catalog=MesSystem;integrated security=True;MultipleActiveResultSets=True;App=EntityFramework"" providerName="System.Data.EntityClient" />
The part that I am missing is the "metadata=res://*/Data.DataContext.EntityFramework.MesSystem.csdl|res://*/Data.DataContext.EntityFramework.MesSystem.ssdl|res://*/Data.DataContext.EntityFramework.MesSystem.msl;"
I want to be able to create a DbContext programmatically passing in a SQL Server connection string but "add on" the metadata portion.
This is what I would like to be generated by the T4 file...
public partial class MesSystemEntities : DbContext
{
public MesSystemEntities()
: base("name=MesSystemEntities")
{
}
public MesSystemEntities(string sqlServerConnectionString)
: base(GetEfConnectionString(sqlServerConnectionString))
{
}
private string GetEfConnectionString(string sqlServerConnectionString)
{
// values added by T4 generation
string format = "metadata=res://*/Data.DataContext.EntityFramework.MesSystem.csdl|res://*/Data.DataContext.EntityFramework.MesSystem.ssdl|res://*/Data.DataContext.EntityFramework.MesSystem.msl;;provider=System.Data.SqlClient;provider connection string=\"{0}\"";
return String.Format(format, sqlServerConnectionString);
}
...
}
My question is how can I get the metadata I need in the T4 generation file to create the Entity Framework connection without hardcoding it for each EDMX file
OR
is there an easier way to load the metadata from the assembly programmatically?

I had the same issue, so instead of relying on all the meta data in the connection string (which I think is not a good idea) I wrote a method to create it from a standard connection string. (I should probably refactor it into an Extension method for DbContext, but this should do)
internal static class ContextConnectionStringBuilder
{
// Modified Version of http://stackoverflow.com/a/2294308/209259
public static string GetEntityConnectionString(string ConnectionString,
Type ContextType)
{
string result = string.Empty;
string prefix = ContextType.Namespace
.Replace(ContextType.Assembly.GetName().Name, "");
if (prefix.Length > 0
&& prefix.StartsWith("."))
{
prefix = prefix.Substring(1, prefix.Length - 1);
}
if (prefix.Length > 1
&& !prefix.EndsWith("."))
{
prefix += ".";
}
EntityConnectionStringBuilder csBuilder =
new EntityConnectionStringBuilder();
csBuilder.Provider = "System.Data.SqlClient";
csBuilder.ProviderConnectionString = ConnectionString.ToString();
csBuilder.Metadata = string.Format("res://{0}/{1}.csdl|"
+ "res://{0}/{1}.ssdl|"
+ "res://{0}/{1}.msl"
, ContextType.Assembly.FullName
, prefix + ContextType.Name);
result = csBuilder.ToString();
return result;
}
}
Basic usage is something like:
string connString =
ConfigurationMananager.ConnectionStrings["name"].ConnectionString;
string dbConnectionString = ContextConnectionStringBuilder(connString,
typeof(MyDbContext));
var dbContext = new MyDbContext(dbConnectionString);

How to in-code supply the password to a connection string in an ADO.Net Entity Data Model

I've been following this tutorial on how to create an OData service.
http://www.hanselman.com/blog/CreatingAnODataAPIForStackOverflowIncludingXMLAndJSONIn30Minutes.aspx
And it works flawlessly ... but, in the Entity Data Model Wizard, when it asks you to "Choose Your Data Connection" it gives you this warning.
"This connection string appears to contain sensitive data (for example, a password) that is required to connect to the database. Storing sensitive data in the connection string can be a security risk. Do you want to include this sensitive data in the connection string?"
If I choose: "No, exclude sensitive data from the connection string. I will set it in my application code."
I do not see where I can, "in my application code" insert the password. (My company stores them encrypted in the registry)
Plus, I have multiple DBs that I need to connect to, depending on the environment (Dev, CA, or Prod) and I need to know what DB is referenced in the connection string to get the correct password.
Thanks.

When you create your context, you can set a connection string. To build this connection string, you can parse the connection string without the password with an EntityConnectionStringBuilder and then parse the inner connection string with an other ConnectionStringBuilder, depending on your browser. Then you can set the password and pass it to the constructor.
var originalConnectionString = ConfigurationManager.ConnectionStrings["your_connection_string"].ConnectionString;
var entityBuilder = new EntityConnectionStringBuilder(originalConnectionString);
var factory = DbProviderFactories.GetFactory(entityBuilder.Provider);
var providerBuilder = factory.CreateConnectionStringBuilder();
providerBuilder.ConnectionString = entityBuilder.ProviderConnectionString;
providerBuilder.Add("Password", "Password123");
entityBuilder.ProviderConnectionString = providerBuilder.ToString();
using (var context = new YourContext(entityBuilder.ToString()))
{
// TODO
}

I added a "dummy" password in the configuration file ("XXXXX"), then replaced that value with the real password in the entity constructor
public MyDatabaseContainer() : base("name=MyDatabaseContainer")
{
Database.Connection.ConnectionString = Database.Connection.ConnectionString.Replace("XXXXX","realpwd");
}

Modify the constructor of the entities
public sampleDBEntities() : base("name=sampleDBEntities")
{
this.Database.Connection.ConnectionString = #"Data Source=.\;Initial Catalog=sampleDB;Persist Security Info=True;User ID=sa;Password=Password123"; ;
}

My sample application was written in "Database First" mode and the "CreateNewConnectionString" method below works just fine (though it doesn't look all that elegant.)
The "CreateNewConnectionString2" method looks really elegant, BUT causes an exception telling me it's only valid in "Code First" mode.
So I'm providing both methods along with the constructor I modified to use my methods. NOTE AND BEWARE, I've modified code generated by a template and that is subject to being overwritten if the code is regenerated. To me it seems like the right place to put it.
If your application was generated in "Code First" mode, you may need to use "CreateNewConnectionString2" (I have not yet tested this option.)
I hasten to admit that I copied both code blocs from other postings as I don't yet know nearly enough about all this to write my own code.
private static string CreateNewConnectionString(string connectionName, string password)
{
var config = System.Web.Configuration.WebConfigurationManager.OpenWebConfiguration("~").ConnectionStrings.ConnectionStrings[connectionName];
//or:
//var config = ConfigurationManager.ConnectionStrings[connectionName];
var split = config.ConnectionString.Split(Convert.ToChar(";"));
var sb = new System.Text.StringBuilder();
for (var i = 0; i <= (split.Length - 1); i++)
{
if (split[i].ToLower().Contains("user id"))
{
split[i] += ";Password=" + password;
}
if (i < (split.Length - 1))
{
sb.AppendFormat("{0};", split[i]);
}
else
{
sb.Append(split[i]);
}
}
return sb.ToString();
}
private static string CreateNewConnectionString2(string connectionName, string password)
{
var originalConnectionString = ConfigurationManager.ConnectionStrings[connectionName].ConnectionString;
var entityBuilder = new EntityConnectionStringBuilder(originalConnectionString);
var factory = DbProviderFactories.GetFactory(entityBuilder.Provider);
var providerBuilder = factory.CreateConnectionStringBuilder();
providerBuilder.ConnectionString = entityBuilder.ProviderConnectionString;
providerBuilder.Add("Password", password);
entityBuilder.ProviderConnectionString = providerBuilder.ToString();
return entityBuilder.ProviderConnectionString;
}
public ChineseStudyEntities()
: base(CreateNewConnectionString("ChineseStudyEntities", "put YOUR password here")) // base("name=ChineseStudyEntities")
{
}

LINQ to SQL connectionstring

I have an application that I want to be able to configure the connection string for my LINQ to SQL. I've tried so many different ways but cannot seem to get it working. I want to do this dynamically in the code when the app is run, the reason for this is that the user can change the connection settings.
If I delete the connectionString out of app.config the application still works OK (communicating) which makes me wonder where I should be changing the connection string?

I think that the best way to do it is a combination of Albin's and Rup's answers. Have a value in the config file, and then read it at run time and feed it to the context constructor, something like this:
WEB.CONFIG:
<appSettings>
<add key="ConString" Value="The connection string" />
CODE:
//read value from config
var DBConnString = System.Configuration.ConfigurationManager.AppSettings("ConString");
//open connection
var dataContext= new MyDataContext(sDBConnString)
this way you can change the connection string even at runtime and it will work and change on the running program.

You can pass an override connection string into the DataContext constructor:
var db = new MyDataContext("Data Source=Something Else;")

The DBML class (YourDataContext) has an overloaded constructor which takes ConnectionString, so try instantiating that instead of the default one.Get the connection string from app.config and use that to create the instance.
YourDataContext context = new YourDataContext (ConfigurationManager.ConnectionStrings["ConnStringInAppConfig"].ConnectionString)

You should change it in app.config. The reason it works without is that the LINQ2SQL designer creates a fallback to the connection string used when designing the DBML. If you define a connection string in app.config that is used instead.

By Default your constructor look like this
public dbDataContext() :
base(global::invdb.Properties.Settings.Default.Enventory_4_0ConnectionString, mappingSource)
{
OnCreated();
}
You can change return value Instead of
//Original
public string Enventory_4_0ConnectionString {
get {
return ((string)(this["Enventory_4_0ConnectionString"]));
}
}
this
//Modified code
public string Enventory_4_0ConnectionString {
get {
return (System.Configuration.ConfigurationManager.ConnectionStrings["Enventory_4_0ConnectionString"].ConnectionString);
}
}

Inside your dbml file designer.cs add this dynamic call to base class constructor. It will work for local, dev and prod automatically pulling from current web.config without need to pass connection every time;
public HallLockerDataContext() :
base(ConfigurationManager.ConnectionStrings["MYDB1"].ConnectionString, mappingSource)
{
OnCreated();
}
Usage:
using (var db = new HallLockerDataContext())
{
}