Web (EmptyWeb) F# version

Should F# version of web project (Web/Empty) be added? We provide one with generator-aspnet and I’m rewriting it for RC: https://github.com/OmniSharp/generator-aspnet/tree/master/templates/projects/fsharp_emptyweb https://github.com/OmniSharp/generator-aspnet/issues/881 Maybe not now, but do you want a PR?

Thanks!

[seancpeters]

It’s probably easiest if I discuss here what needs to be done.

Let’s use the C# empty web template as an example: https://github.com/dotnet/templating/tree/master/template_feed/Microsoft.DotNet.Web.ProjectTemplates/content/EmptyWeb-CSharp

For an F# empty web template, you’ll want to make a directory /EmptyWeb-FSharp/ at the same level as the /EmptyWeb-CSharp/ directory. Everything for the F# template will go under /EmptyWeb-FSharp/ It’s probably easiest to name the files similar to how they’re named in the C# template - you’ll want:

• Company.WebApplication1.fsproj
• Program.fs
• Startup.fs

We also need to look at the template.json file for the C# emptyweb project: https://github.com/dotnet/templating/blob/master/template_feed/Microsoft.DotNet.Web.ProjectTemplates/content/EmptyWeb-CSharp/.template.config/template.json

You’ll need to make a /EmptyWeb-FSharp/.template.config/template.json file for the F# emptyweb project. You can copy the C# one, and just make a few changes. Here’s the start of the file, it’s the only place changes will need to be made:

{
  "author": "Microsoft",
  "classifications": ["Web", "Empty"],
  "name": "Empty ASP.NET Core Web Application",
  "groupIdentity": "Microsoft.Web.Empty",
  "identity": "Microsoft.Web.Empty.CSharp",
  "shortName": "web",
  "tags": {
    "language": "C#",
    "type": "project"
  },
  "sourceName": "Company.WebApplication1",
  "preferNameDirectory": true,
  "symbols": {
    "IncludeApplicationInsights": {
      "type": "parameter",
      "datatype": "bool",
      "defaultValue": "false",
      "description": "Whether or not to include Application Insights in the project"
    },
    "Framework": {
      "type": "parameter",
      "datatype": "choice",
      "choices": [
        {
          "choice": "netcoreapp1.0",
          "description": "Target netcoreapp1.0"
        },
        {
          "choice": "netcoreapp1.1",
          "description": "Target netcoreapp1.1"
        }
      ],
      "defaultValue": "netcoreapp1.0"
    },

I don’t think your F# template has Application Insights built in, so we can remove the IncludeApplicationInsights section under the “symbols”. You’ll want to change “language”: “C#” … to be “language”: “F#” And change the “identity”: “Microsoft.Web.Empty.CSharp” … to be “identity”: “Microsoft.Web.Empty.FSharp”, No other changes should be necessary in the template.json file (copy)

This part doens’t need to be changed. But it is important for the changes we’ll need to make in the .fs files: “sourceName”: “Company.WebApplication1”, When you create a template, the engine determines a string value for “sourceName”.

Sidenote: How the sourceName is determined with the command “dotnet new”: - if you provide "-n Name"option, then sourceName = Name - if you do not provide “-n Name”, but provide a “-o DirectoryName” option, then the sourceName = DirectoryName - if you specify both “-o DirectoryName” and “-n Name”, then sourceName = Name - if you don’t specify either option, then sourceName = the name of the current directory

That value will replace the string literal “Company.WebApplication1” in all the filenames, and in all the file content in the template. For example, if I create a template with: dotnet new web -n MyWebProject all instances of “Company.WebApplication1” will be replaced with “MyWebProject”.

Since we are naming the proj file “Company.WebApplication1.fsproj” in the template, the output file name will become “MyWebProject.fsproj”

The same idea should be used for the namespace value in the .fs files. In the Program.fs & Startup.fs files, you have the line: open <%= namespace %>

For the dotnet template, this will become: open Company.WebApplication1

… and when the template is generated, the output .fs files will contain the line: open MyWebProject

The .fsproj file contains this line: <TargetFramework><%= dotnet.targetFramework %></TargetFramework> For dotnet templates, we do this differently. Under the “symbols” section of the template.json file, there is a “Framework” section. Since it has “type”: “parameter”, it’s something the user can specify. We use the specified value to format the TargetFramework. You can copy exactly what is in the existing C# template, specifically:

  <PropertyGroup>
    <TargetFramework Condition="'$(Framework)' != 'netcoreapp1.1'">netcoreapp1.0</TargetFramework>
    <TargetFramework Condition="'$(Framework)' == 'netcoreapp1.1'">netcoreapp1.1</TargetFramework>

The template engine evaluates the Condition statements, the ones that are true are written to the target, others are not.

There is one more extra file to add to your template. It should be: /EmptyWeb-FSharp/.template.config/dotnetcli.host.json and can contain exactly this:

{
  "symbolInfo": {
    "Framework": {
      "longName": "framework"
    }
  }
}

Everything else in the template is general-purpose. This file will only be used by the command line “dotnet new”. It’s just saying that for the parameter “Framework”, we want the parameter to be specified with “framework” instead.

I think I covered everything your template already does. If I missed anything, or if anything is unclear, please let me know.

[mlorbetske]

Yep, it needs the nightly of the 2.0 cli unfortunately. I believe that’s the total set of differences, @glennc can probably point out any changes that are coming.