Developing an ASP. NET Core application using dotnet Watch

Developing an ASP. NET Core application using dotnet Watch

Original: Developing ASP. NET Core applications using dotnet Watch
Victor Hurdugaci
Translation: Thumbelina (Kiler)
Proofreading: Liu Yi (alexlewis), Huden (Seay)

Introduced

dotnet watchis a tool for the development phase to use commands in the event of a change in the source file dotnet . When the code changes, it can be used to compile, run tests, or publish operations.

In this tutorial, we will use an existing WEBAPI application that calculates the sum of two numbers and the product, demonstrating how to use it dotnet watch . The sample application intentionally contains an error that we will fix as part of this tutorial.

Getting Started

Start downloading the sample program. The sample program contains two items WebApp (Web application) and WebAppTests (a unit test project that is a companion to the Web application)

In the command line console, go to the directory where you downloaded the sample program and run the following command:

1.dotnet restore
2.cd WebApp
3.dotnet run

The console output displays the following information indicating that the application is running and waiting for the request:

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$ dotnet runproject WebApp (. Netcoreapp,version=v1. 0) 'll be compiled because inputs were modifiedcompiling WebApp for .  Netcoreapp,version=v1. 0Compilation succeeded. 0 Warning (s) 0 Error (s) time elapsed :xx:02.6049991Hosting environment:productioncontent Root path: /users/user/dev/aspnet/docs/aspnet/tutorials/dotnet-watch/sample/ Webappnow listening on : http://localhost:5000application started. Press CTRL + C to shut down.                 

In a Web browser, navigate to the http://localhost:5000/api/math/sum?a=4&b=5 page and you will see the results 9 .

If you navigate to the http://localhost:5000/api/math/product?a=4&b=5 page, you expect to get results 20 . But it actually returned 9 .

We'll fix this problem.

Project to add dotnet watch

1. Add references in the configuration section of the Webapp/project.json file as follows tools Microsoft.DotNet.Watcher.Tools :

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"tools": {  "Microsoft.DotNet.Watcher.Tools": "1.0.0-preview2-final" //手工高亮},

2, run dotnet restore .

The console output displays the following information:

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Log:restoring PackagesFor/users/user/dev/aspnet/docs/aspnet/tutorials/dotnet-watch/sample/webapp/project.json...log:restoring packages for tool  Microsoft.DotNet.Watcher.Tools ' in /users/user/dev/aspnet/docs/aspnet/tutorials/ Dotnet-watch/sample/webapp/project.json ... log:installing Microsoft.DotNet.Watcher.Core 1.0.0-preview2-final. log:installing Microsoft.DotNet.Watcher.Tools 1.0.0- Preview2-final.            

Use dotnet watchRun dotnetCommand

Any dotnet commands related to this can be dotnet watch run in such a way: for example:

Command	take Watch's command.
dotnet run	dotnet watch run
dotnet run -f net451	dotnet watch run -f net451
dotnet run -f net451 -- --arg1	dotnet watch run -f net451 -- --arg1
dotnet test	dotnet watch test

In order to WebApp run in watcher mode, run the command in the WebApp directory dotnet watch run . The console output displays the following information indicating that the dotnet watch code file is now being monitored:

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user$ dotnet watch Run[dotnetwatcher] info:running dotnet with The following arguments:run[dotnetwatcher] info:dotnet process id: 39746project WebApp (. Netcoreapp,version=v1.0) was previously compiled. Skipping compilation. Hosting environment:productioncontent root path: /users/user/dev/aspnet/Docs/aspnet/tutorials/dotnet-watch/sample/webappnow listening on: http://localhost : 5000Application started. Press CTRL + C to shut down.              

In dotnet watchMode to modify

Confirm that dotnet watch the mode is running.

Let's fix the two-digit multiplication result that was found above error.

Open the file Webapp/controllers/mathcontroller.cs.

We intentionally introduced the error in the code.

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public static int Product(int a, int b){ // We have an intentional bug here // + should be * return a + b;//手工高亮}

By replacing the code with the a + b a * b fix error.

Save the file. The console output displays the following information indicating that a dotnet watch change to the file was detected and the application was restarted.

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[Dotnetwatcher]Info:fileChanged/users/user/dev/aspnet/docs/aspnet/tutorials/dotnet-watch/sample/webapp/controllers/mathcontroller.cs[dotnetwatcher]Info:running dotnet with the followingArguments:run[dotnetwatcher]Info:dotnet processId:39940Project WebApp (. Netcoreapp,version=v1. 0) 'll be compiled because inputs were modifiedcompiling WebApp for . Netcoreapp,version=v1. 0Compilation succeeded. 0 Warning (s) 0 Error (s) time elapsed :xx:03.3312829Hosting environment:productioncontent Root path: /users/user/dev/aspnet/docs/aspnet/tutorials/dotnet-watch/sample/ Webappnow listening on : http://localhost:5000application started. Press CTRL + C to shut down.                 

Verify http://localhost:5000/api/math/product?a=4&b=5 that the link returns the correct result.

Use dotnet watchRun Tests

File monitoring can also run other dotnet commands such as test or publish .

1. Open the WebAppTests directory and confirm that the Project.json file is already included dotnet watch .

2, run the dotnet watch test command.

If you have previously MathController fixed the error in, you will see the console output showing the following information, otherwise you will see the test failed information:

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Webapptests user$ dotnet Watch Test[dotnetwatcher]Info:running dotnet with the followingArguments:test[dotnetwatcher]Info:dotnet processId:40193Project WebApp (. Netcoreapp,version=v1.0) was previously compiled. Skipping compilation. Project webapptests (. Netcoreapp,version=v1.0) was previously compiled. Skipping compilation.xUnit.net. NET CLI Test Runner (64-bit. NET Core OSX.10.11-x64)Discovering:webapptestsDiscovered:webapptestsStarting:webapptestsfinished:webapptests=== TEST execution SUMMARY = = = WebapptestsTotal : 2, Errors: 0, Failed: 0, skipped: 0, Time : 0.259sSUMMARY: Total  : 1 targets, Passed: 1, Failed: 0.[dotnetwatcher] info:dotnet exit code: 0[dotne Twatcher] info:waiting for a file to change before restarting dotnet ...      

Once all the tests are running, the monitor will instruct him to dotnet test wait for a file change before the next reboot.

3. Open the controller Webapp/controllers/mathcontroller.cs file and modify the code. If you do not fix multiplication errors, modify them immediately. and save.

dotnet watchA file change is detected and the test is rerun. The console output displays the following information:

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[Dotnetwatcher]Info:fileChanged/users/user/dev/aspnet/docs/aspnet/tutorials/dotnet-watch/sample/webapp/controllers/mathcontroller.cs[dotnetwatcher]Info:running dotnet with the followingArguments:test[dotnetwatcher]Info:dotnet processId:40233Project WebApp (. Netcoreapp,version=v1.0) 'll be compiled because inputs were modifiedcompiling WebAppFor. Netcoreapp,version=v1.0Compilation succeeded.0 Warning (s)0 Error (s) time elapsed00:00:03.2127590Project webapptests (. Netcoreapp,version=v1.0) 'll be compiled because dependencies changedcompiling webapptestsFor. Netcoreapp,version=v1.0Compilation succeeded.0 Warning (s)0 Error (s) time elapsed00:00:02.1204052xunit.net. NET CLI Test Runner (64-bit. NET Core OSX.10.11-x64)Discovering:webapptestsDiscovered:webapptestsStarting:webapptestsfinished:webapptests=== TEST execution SUMMARY = = = WebapptestsTotal : 2, Errors: 0, Failed: 0, skipped: 0, Time : 0.260sSUMMARY: Total  : 1 targets, Passed: 1, Failed: 0.[dotnetwatcher] info:dotnet exit code: 0[dotne Twatcher] info:waiting for a file to change before restarting dotnet ...      

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Developing an ASP. NET Core application using dotnet watch