WebAPI Core 2 Multiple connection string with same context

Question

I am developing webapi with some knowledge of Core 2.0 I need to create two link to produce different result from different database both database schema are the same.

Like https://localhost:5000/m/University
or https://localhost:5000/v/University
They both fire in different database with same webapi application and give result it. I can produced result but I have to either create two webapi project or change connection string ("MConn") in Start up class.

  public void ConfigureServices(IServiceCollection services)
    {
        services.Configure<IISOptions>(options => { options.AutomaticAuthentication = true; });
        services.AddDbContext<PIDBContext>(opt => opt.UseSqlServer(Configuration.GetConnectionString("MConn")));
        services.AddMvc();
    }

Could you help me how to use same Webapi project with different connection string based on Https request?

Thanks

See my question, how to dynamically change connection string, might be helpful. — Yurii N.
– Yurii N., Commented Nov 30, 2017 at 17:15
Thanks for reply but I have at least 50 controller with different result produce with those controller route. That means need to change lot. — PantherUSA
– PantherUSA, Commented Nov 30, 2017 at 17:43

Georg Plaz · Accepted Answer · 2018-05-24 11:33:19Z

Found the solution:

Create DbContextFactory

public static class DbContextFactory
{
    public static Dictionary<string, string> ConnectionStrings { get; set; }

    public static void SetConnectionString(Dictionary<string, string> connStrs)
    {
        ConnectionStrings = connStrs;
    }

    public static AppContext Create(string connid)
    {
        if (!string.IsNullOrEmpty(connid))
        {
            var connStr = ConnectionStrings[connid];
            var optionsBuilder = new DbContextOptionsBuilder<AppContext >();
            optionsBuilder.UseSqlServer(connStr);
            var db = new AppContext (optionsBuilder.Options);
            return db;
        }
        else
        {
            throw new ArgumentNullException("Connection failed becuase of no Connection ID");
        }
   } 
}

Project Json file:

{
    "ConnectionStrings": {
    "Sample1con": "your 1st connection string",
    "Sample2con": "your 2nd connection string"
    }
}

In Configure method in Startup class declare Dictionary

Dictionary<string, string> connStrs = new Dictionary<string, string>();
connStrs.Add("p", Configuration.GetConnectionString("Sample1con"));
connStrs.Add("m", Configuration.GetConnectionString("Sample2con"));
DbContextFactory.SetConnectionString(connStrs);

In action usage

var _context = DbContextFactory.Create(db); ///Db would be your URL string.

Nishith Shah · Accepted Answer · 2017-11-30 18:27:16Z

1

Do you have to have two links? If not, can't you achieve that by doing following.

Pass a parameter to your route, and use that route to decide which context to use.
So for https://localhost:5000/University/m you will use one context and for https://localhost:5000/University/v you will use another context.
As both the databases have same schema there wouldn't be any problem parsing the results to same object models.

answered Nov 30, 2017 at 18:27

Nishith Shah

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1 Comment

PantherUSA Over a year ago

This is nice way to approach if only small change in few controller. I have 50 or more controller and multiple method as well. So There would be lots of duplicate code. Is this only option?

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