How to Determine the ASP.NET Core Environment in my Gulpfile.js

Question

I am using ASP.NET Core MVC 6 using Visual Studio 2015. In my gulpfile.js script I want to know if the hosting environment is Development, Staging or Production so that I can add or remove source maps (.map files) and do other things. Is this possible?

UPDATE

Relevant issue on GitHub.

Answer 1

You can use the ASPNETCORE_ENVIRONMENT (Was formerly ASPNET_ENV in RC1) environment variable to get the environment. This can be done in your gulpfile using process.env.ASPNETCORE_ENVIRONMENT.

If the environment variable does not exist, you can fallback to reading the launchSettings.json file which Visual Studio uses to start your application. If that also does not exist, then fallback to using the Development environment.

I wrote the following JavaScript object to make dealing with the environment in gulpfile.js easier. You can find the full gulpfile.js source code here.

// Read the launchSettings.json file into the launch variable.
var launch = require('./Properties/launchSettings.json');

// Holds information about the hosting environment.
var environment = {
    // The names of the different environments.
    development: "Development",
    staging: "Staging",
    production: "Production",
    // Gets the current hosting environment the application is running under.
    current: function () { 
        return process.env.ASPNETCORE_ENVIRONMENT ||
            (launch && launch.profiles['IIS Express'].environmentVariables.ASPNETCORE_ENVIRONMENT) ||
            this.development;
    },
    // Are we running under the development environment.
    isDevelopment: function () { return this.current() === this.development; },
    // Are we running under the staging environment.
    isStaging: function () { return this.current() === this.staging; },
    // Are we running under the production environment.
    isProduction: function () { return this.current() === this.production; }
};

See this answer for how to set the environment variable.

Answer 2

You would need to set the NODE_ENV environment variable in each environment and then in your gulpfile, read it in using process.env.NODE_ENV.

Have a look at https://stackoverflow.com/a/16979503/672859 for additional details.