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](https://stackoverflow.com/questions/36816215/dynamically-change-connection-string-in-asp-net-core), might be helpful. — Yurii N., Nov 30 '17 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, Nov 30 '17 at 17:43

score 3 · Answer 1 · edited May 24 '18 at 11:33

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.

score 1 · Answer 2 · answered Nov 30 '17 at 18:27

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 '17 at 18:27

Nishith Shah

313
1
3
11

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? – PantherUSA Nov 30 '17 at 20:12

WebAPI Core 2 Multiple connection string with same context

2 Answers2