Launch IIS Express to run ASP.NET Core Apps - asp.net-core

Question

I wish to run my ASP.NET Core App by launching it from IIS Express using command line.
I stumbled across this article which says
So in fact Visual Studio silently adds the two environment variables
when launching IIS Express, so that ASP.NET Core related bits can be
injected.
LAUNCHER_ARGS: -debug -p “C:\Program Files\dotnet\dotnet.exe” -a “exec
\”C:\Users\lextm\documents\visual studio
2017\Projects\WebApplication2\WebApplication2\bin\Debug\netcoreapp1.0\WebApplication2.dll\””
-pidFile “C:\Users\lextm\AppData\Local\Temp\2\tmpFD6D.tmp” -wd “C:\Users\lextm\documents\visual studio
2017\Projects\WebApplication2\WebApplication2”
The tmp file in -pidFile “C:\Users\lextm\AppData\Local\Temp\2\tmpFD6D.tmp” can always change. How do I add LAUNCHER_ARGS as environment variable which will make it work even if the tmp file changes?
Let me know if there is any easier way to launch IIS Express to run ASP.NET Core Apps with command line or powershell scripts.

Answer 1

You are looking for [System.IO.Path]::GetTempFileName() method. It creates empty temp file on file system and returns its unique name.
I'm currently using the following PowerShell script to run my .NET Core 2.0 App:
$env:LAUNCHER_ARGS = "-p ""<path to dotnet.exe>"" -a ""exec \""<path to webapp main dll>\"""" -pidFile $([System.IO.Path]::GetTempFileName()) -wd ""<path to webapp root folder>"" -pr <project name>"
$env:LAUNCHER_PATH = "<path to VSIISExeLauncher.exe>"
& "<path to iisexpress.exe>" /config:"<path to applicationhost.config>" /site:"<webapp name>"
Placeholders (text within angle brackets) have to be filled with the corresponding values. You can find them out by running your project from Visual Studio and inspecting environment variables of iisexpress.exe process using Process Explorer as shown above in the link you provided.

Answer 2

In .NET Core 3 the solution to this problem has changed. Follow these steps.
1) The environment variables should now be:
LAUNCHER_ARGS=exec "C:\YourWebApiProject\bin\Debug\netcoreapp3.1\YourWebApiProject.dll"
LAUNCHER_PATH=C:\Program Files\dotnet\dotnet.exe
Change the first path to your dll path and ensure the .NET version in the path is correct. Note that there is no longer a need to create a temp file.
2) Ensure that both modules AspNetCoreModule and AspNetCoreModuleV2 are registered in the file .vs\{your solution name}\config\applicationhost.config as follows:
Under <system.webServer> <globalModules> add:
<add name="AspNetCoreModule" image="%IIS_BIN%\aspnetcore.dll" />
<add name="AspNetCoreModuleV2" image="%IIS_BIN%\Asp.Net Core Module\V2\aspnetcorev2.dll" />
Under <sectionGroup name="system.webServer"> add:
<section name="aspNetCore" overrideModeDefault="Allow" />
Under <location path="" overrideMode="Allow"> <system.webServer> <modules> add:
<add name="AspNetCoreModule" lockItem="true" />
<add name="AspNetCoreModuleV2" lockItem="true" />
It's also a good idea to make this change to the templates for this file which are located at %PROGRAMFILES%\IIS Express\config\templates\PersonalWebServer\applicationhost.config and %PROGRAMFILES(x86)%\IIS Express\config\templates\PersonalWebServer\applicationhost.config so that new VS solutions you create automatically get these changes to their configs. (Credit to this post)
3) Be mindful of whether you're using 32 or 64 bit IIS Express. (If you're on a 64 bit machine then 32 bit IIS Express = C:\Program Files (x86)\IIS Express, 64 bit = C:\Program Files\IIS Express) In my case, 32 bit had worked fine previously but after migrating to .NET Core 3 I had to use 64 bit or else the above modules wouldn't load.

Answer 3

I needed to run multiple .Net Core API endpoints at a time easily without popping open Visual Studio for each and every one of them. I ended up using answers here to build the following:
iisaspnet.bat:
#echo off
:: Args are like:
:: MobileApi
:: C:\Users\chris\Dropbox\Code\2017\VbaMeasureHcp\src\HCPMobileApi
:: MobileApi\bin\Debug\netcoreapp2.2\MobileApi.dll
:: .vs\MobileApp\config\applicationhost.config
setlocal
set PATH=%PATH%;C:\Program Files\IIS Express
set LAUNCHER_ARGS=exec %2\%3
set LAUNCHER_PATH=C:\Program Files\dotnet\dotnet.exe
iisexpress /site:%1 /config:"%2\%4"
:: Comment out line below to check for errors
exit
The first arg is the name of the Project - the name in Visual Studio (in some scenarios people go rogue and name their Project file one thing and the Project itself another thing - you want the Project name, not the file name, in this scenario).
The second arg is the root folder for third and fourth args.
The third arg is where to find the compiled Project DLL
The fourth arg is where to find the applicationhost.config that explains how to launch the site. As you'll see below, this is generally found in your .vs folder, but, where this exists can get a little crazy depending on how creative people get with organizing their Solution and Project folders. Generally the .vs folder is going to sit in the same folder as the .sln file, so it may be far from the Project folder/files.
This will be less helpful, but here's the batch file that kicks off the IIS Express windows, so you can see iisaspnet.bat in use:
start iisaspnet.bat MobileApi C:\Users\chris\Dropbox\Code\2017\VbaMeasureHcp\src\HCPMobileApi MobileApi\bin\Debug\netcoreapp2.2\MobileApi.dll .vs\MobileApp\config\applicationhost.config
start iisaspnet.bat HCP.MasterDataApi C:\Users\chris\Dropbox\Code\2017\VbaMeasureHcp\src MasterData\Api\HCP.MasterDataApi\bin\Debug\netcoreapp2.2\HCP.MasterDataApi.dll Solutions\.vs\MasterData\config\applicationhost.config
start iisaspnet.bat HCP.SecurityApi C:\Users\chris\Dropbox\Code\2017\VbaMeasureHcp\src Security\Api\HCP.SecurityApi\bin\Debug\netcoreapp2.2\HCP.SecurityApi.dll Solutions\.vs\Security\config\applicationhost.config
start iisaspnet.bat HCP.BillingApi C:\Users\chris\Dropbox\Code\2017\VbaMeasureHcp\src Billing\Api\HCP.BillingApi\bin\Debug\netcoreapp2.2\HCP.BillingApi.dll Solutions\.vs\Billing\config\applicationhost.config
start iisaspnet.bat HCP.ClientApi C:\Users\chris\Dropbox\Code\2017\VbaMeasureHcp\src Client\Api\HCP.ClientApi\bin\Debug\netcoreapp2.2\HCP.ClientApi.dll Solutions\.vs\Client\config\applicationhost.config
start iisaspnet.bat HCP.EmployeeApi C:\Users\chris\Dropbox\Code\2017\VbaMeasureHcp\src Employee\Api\HCP.EmployeeApi\bin\Debug\netcoreapp2.2\HCP.EmployeeApi.dll Solutions\.vs\Employee\config\applicationhost.config
The way the parameters work could likely be far simpler if the way the Projects, Solutions, etc were stored and named was more consistent, but, this is an existing set of Solutions I had no control over with scattered naming etc, and, the chaos above may be more helpful anyway for understanding how to call these commands.
The result is that running one command kicks off 6 IIS Express command windows for me, requests get logged to each of their windows, and I just type Q in each window to kill them.