Entity Framework - How to get relative file path in seed method

Question

Why is filePath null? Any ideas on how to get the relative filePath?

internal sealed class Configuration : DbMigrationsConfiguration<MvcProject.Models.FileDb>
{
    public Configuration()
    {
        // code here is not relevant to question
    }
    protected override void Seed(MvcProject.Models.FileDb context)
    {    
        string filePath = System.Web.HttpContext.Current.Server.MapPath("~/Content/File.txt");

        // read File.txt using filePath and update the database
    }
}

I have the above code in Configuration.cs file in Migrations folder created when entity framework is set up on an ASP .NET MVC project

When I run "Update-Database -Verbose" in Package Manager Console I get an error that filePath is null.

If I manually set filePath with an absolute URL to the file:

string filePath = "C:/Users/User1/My Documents/Visual Studio 2012/Projects/MvcProject/Content/File.txt";

Everything works fine.

Obviously the goal is to have a relative path to enable work with different developers on different setups.

Truth be told all I need is the file - not necessarily the path. Any help will be appreciated.

the filepath is null, or the `System.Web.HttpContext.Current` and you have an exception ? — Aristos, Apr 28 '13 at 08:23
Aristos, I know filePath is null (or System.Web.HttpContext.Current is). What I don't know is why nor a way to get the filePath in the seed method — S.A., Apr 28 '13 at 08:49
If you do not know what is null, then you probably not found how to solve it. I think that you call that not from a page and the `HttpContext` is null and that the issue here. At the end your question must be accurate and not let us imaging the real problems - of course you can follow that only is you seek for solutions. — Aristos, Apr 28 '13 at 08:54
I posted an answer to your question here: http://stackoverflow.com/questions/19323437/how-to-get-file-path-in-entity-framework-seed-method-without-httpcontext-execut/20070329#20070329 — Wiebe Tijsma, Nov 19 '13 at 11:31

Wiebe Tijsma · Accepted Answer · 2017-09-10T18:26:27.220

25

I use this function to map paths inside the Seed method, not very clean but it works:

private string MapPath(string seedFile)
{
    if(HttpContext.Current!=null)
        return HostingEnvironment.MapPath(seedFile);

    var absolutePath = new Uri(Assembly.GetExecutingAssembly().CodeBase).LocalPath; //was AbsolutePath but didn't work with spaces according to comments
    var directoryName = Path.GetDirectoryName(absolutePath);
    var path = Path.Combine(directoryName, ".." + seedFile.TrimStart('~').Replace('/','\\'));

    return path;
}

then just call it using:

   using (var streamReader = new StreamReader(MapPath("~/Data/MyFile.csv")))

edited Sep 10 '17 at 18:26

answered Nov 19 '13 at 11:35

Wiebe Tijsma

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2

On my dev machine, this puts %20s in the path, so if you have spaces in your folder names it fails. – John Shedletsky Feb 19 '15 at 02:04
1

You, are a beautiful person... My goodness I've been looking left right and centre for this bloodpepfoefoisjk;gfiorjeogjersgio. THANKYOU! – Jimmyt1988 Apr 14 '15 at 10:30
1

@Jimmyt1988 *blush* :) – Wiebe Tijsma Apr 14 '15 at 10:40
4

You can use .LocalPath insted of .AbsolutePath to get spaces instead of %20 – David Aug 18 '15 at 07:04
1

@WiebeTijsma, you are my savior ! Thank you! – Dimitri Oct 03 '18 at 08:19

score 0 · Answer 2 · edited May 23 '17 at 12:34

As I say , I belive that you call it from a page and the System.Web.HttpContext.Current is null, because MapPath function never return null with a not null input - so you get an exception there.

Try that alternative:

string filePath = HttpRuntime.AppDomainAppPath + "/Content/File.txt";

or

string filePath = HostingEnvironment.MapPath("~/Content/File.txt");

Related question: How to access the HttpServerUtility.MapPath method in a Thread or Timer?

Entity Framework - How to get relative file path in seed method

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