Tag Helpers: Create an 'environment' Tag Helper

[DamianEdwards]

A new Tag Helper that utilizes the conditional content mode (aspnet/Razor#221) to only render its contents if the current IHostingEnvironment.EnvironmentName matches the specified name. The target environment names can be specified as a comma separated list via the names attribute (string). In the case of the environment not currently matching, the contents would not even be executed.

Usage

<environment names="">
</environment>

If the names attribute is omitted, the contents are always rendered.

Attributes

Attribute Name	Type	Details
names	string	A comma separated list of environment names in which the content should be rendered

Example

<environment names="Development">
    <script src="~/js/file1.js"></script>
    <script src="~/js/file2.js"></script>
</environment>
<environment names="Staging,Production">
    <script src="~/js/site.js"></script>
</environment>

[Bartmax]

why do you have name and names ? I suggest to keep only with names so one can change from one to multiple only modifying the content.

Also, can this envitorment tag would be anything ? so if we have a model like :

public bool IsValid {get;set;}
public string Name {get;set;}

one my author

<conditional IsValid="true"> .. </conditional>
or
<condition name="Bart, Damian"> ... </condition>

and for the enviroment example:

<condition environment="Production, Staging">...</condition>

or maybe better <if environment="Production, Staging"> ... </if>

[Bartmax]

is there a way to implement fallback environment when the enviroment does not match any of listed names ?
is there a way to implement a NOT condition ? like <environment names="!Staging">

I'm afraid we may see lots of duplicated code... or lots of enviroment clauses. Is the view really the responsable to use one or another ?

[DamianEdwards]

@Bartmax agree on name/names, I'll change that.

You could certainly build a more generic conditional/if tag helper yourself, but we're not planning on doing it. We see environment being something people often conditionally render content on so we're promoting it as a first class tag helper, but fundamentally we don't to go super generic in the tag helpers (and have Razor end up looking like Spark).