GraphQL教程（三） .net core api

GraphQL笔记来源是杨旭视屏教程

今天学习用添加
首先需要创建三个类，MovieInput(数据对应的模板类)、MovieInputType(GraphQL需要的类型)、MovieMutation(添加处理)
第二步是在MovieSchema类对MovieMution进行添加（第二篇文章说过此类用于对增删查改类处理）
第三步是在startup类中进行注册
然后就可以用GraphQL进行添加处理
第四步介绍下文档

直接上代码
MovieInput类，注意其中没有Id属性了，因为添加时自动增加Id属性

using System;

namespace GraphStudy.Movies.Movies
{
    //添加类的模板
    public class MovieInput
    {
        public string Name { get; set; }
        public DateTime ReleaseDate { get; set; }//上映时间
        public string Company { get; set; }
        public int ActorId { get; set; }//演员ID
        public MovieRating MovieRating { get; set; }//电影等级枚举
    }
}

MovieInputType类，(GraphQL需要的类型)，这里的类型与MovieInput对应，同样没有，注意枚举有点特殊，

using GraphQL.Types;
using GraphStudy.Movies.Movies;

namespace GraphStudy.Movies.Schema
{
    public class MovieInputType:InputObjectGraphType<MovieInput>
    {
        public MovieInputType()
        {
            Name = "MovieInput";

            Field(x => x.Name);
            Field(x => x.ActorId);
            Field(x => x.Company);
            Field(x => x.ReleaseDate);
            Field(x => x.MovieRating,type:typeof(MovieRatingEnum));
        }
    }
}

MovieMutation(添加处理)

using GraphQL.Types;
using GraphStudy.Movies.Movies;
using GraphStudy.Movies.Services;
using System.Linq;

namespace GraphStudy.Movies.Schema
{
    public class MoviesMutation:ObjectGraphType
    {
        public MoviesMutation(IMovieService movieService)
        {
            Name = "Mutation";

            //返回类型为MovieType，所以Field<MovieType>
            FieldAsync<MovieType> 
            (
                "createMovie",
                arguments: new QueryArguments(new QueryArgument<NonNullGraphType<MovieInputType>>
                {
                    Name = "movie"//注意此处无需标点符号，不然会出错
                }),
                resolve: async context =>
                {
                    var movieInput = context.GetArgument<MovieInput>("movie");//此处movie的字应该与arguments里面的Name字一样，模板为MovieInput
                    //用异步处理下面Id自增
                    var movies = await movieService.GetAsyncs();
                    var maxId = movies.Select(x => x.Id).Max();

                    var movie = new Movie
                    {
                        Id = ++maxId,
                        Name = movieInput.Name,
                        Company = movieInput.Company,
                        ActorId = movieInput.ActorId,
                        MovieRating = movieInput.MovieRating,
                        ReleaseDate = movieInput.ReleaseDate
                    };
                    //检车下MovieService类中CreateAsync方法是否写对，
                    var result = await movieService.CreateAsync(movie);
                    //返回结果，返回类型为MovieType，他里面有Id属性
                    return result;
                }
            );
        }
    }
}

在MovieSchema类对MovieMution进行添加，所有的增删改查都在其中添加，同意在startup中注册服务

using GraphQL;

namespace GraphStudy.Movies.Schema
{
    public class MovieSchema:GraphQL.Types.Schema
    {
        public MovieSchema(IDependencyResolver dependencyResolver, 
            MoviesQuery moviesQuery,
            MoviesMutation moviesMutation)
        {
            DependencyResolver = dependencyResolver;
            Query = moviesQuery;
            Mutation = moviesMutation;
        }
    }
}

最后在startup中进行注册处理，服务注册添加类型与增删查改的方法

using System;
using System.Collections.Generic;
using System.Linq;
using System.Threading.Tasks;
using GraphQL;
using GraphQL.Server;
using GraphQL.Server.Ui.Playground;
using GraphStudy.Movies.Schema;
using GraphStudy.Movies.Services;
using Microsoft.AspNetCore.Builder;
using Microsoft.AspNetCore.Hosting;
using Microsoft.AspNetCore.Http;
using Microsoft.Extensions.DependencyInjection;


namespace GraphStudy.Api
{
    public class Startup
    {
        // This method gets called by the runtime. Use this method to add services to the container.
        // For more information on how to configure your application, visit https://go.microsoft.com/fwlink/?LinkID=398940
        public void ConfigureServices(IServiceCollection services)
        {
            services.AddSingleton<IMovieService, MovieService>();
            services.AddSingleton<IActorService, ActorService>();

            services.AddSingleton<ActorType>();
            services.AddSingleton<MovieRatingEnum>();
            services.AddSingleton<MovieType>();
            services.AddSingleton<MoviesQuery>();
            services.AddSingleton<MovieSchema>();
		////
            services.AddSingleton<MovieInputType>();
            services.AddSingleton<MoviesMutation>();
		///
            services.AddSingleton<IDependencyResolver>(s => new FuncDependencyResolver(s.GetRequiredService));


            // Add GraphQL services and configure options
            services.AddGraphQL(options =>
                {
                    options.EnableMetrics = true;
                    options.ExposeExceptions = true;//是否包容异常，改下
                })
                .AddWebSockets() // Add required services for web socket support
                .AddDataLoader(); // Add required services for DataLoader support
        }

        // This method gets called by the runtime. Use this method to configure the HTTP request pipeline.
        public void Configure(IApplicationBuilder app, IHostingEnvironment env)
        {
            if (env.IsDevelopment())
            {
                app.UseDeveloperExceptionPage();
            }

            // this is required for websockets support
            app.UseWebSockets();

            // use websocket middleware for ChatSchema at path /graphql
            app.UseGraphQLWebSockets<MovieSchema>("/graphql");

            // use HTTP middleware for ChatSchema at path /graphql
            app.UseGraphQL<MovieSchema>("/graphql");

            //去点另外两个UI，因为我们刚刚添加的包就是Playground，所以保留这个就行
            // use graphql-playground middleware at default url /ui/playground
            app.UseGraphQLPlayground(new GraphQLPlaygroundOptions());

        }
    }
}

最后运行

好了添加成功，那个actor里面的内容与ActorService里面的种子数据一一对应
接下来查询下，点击中间那个按钮运行，选择Query

可以看到添加成功

看看query查询语句，mutation添加语句

# Try to write your query here
query Query{
  movies{
    id
    name
    company
    movieRating
    releaseDate
    actorId
    customString
    actor{
      id
      name
    }
  }
}

mutation Create($input:MovieInput!){
  createMovie(movie: $input){

    name
    company
    movieRating
    releaseDate
    actorId
    actor{
      id
      name
    }
  }
}

其中添加里这句话解释下
mutation Create($input:MovieInput!){
createMovie(movie: $input){

Create是添加语句的别名，

createMovie为MovieMutation类里面的FieldAsync下面那个名字"createMovie"，与之对应

createMovie(movie: $input)中括号内需要添加一个参数变量，movie: $input表示参数变量，$input传递参数变量

Create($input:MovieInput!)中($input:MovieInput!)表示定义变量，MovieInput表示变量类型,置于为什么是MovieInput这个呢
可能和这句MovieMutation类var movieInput = context.GetArgument(“movie”);里面的有关，其中的感叹号！表示必填

五、文档
相信大家都看到了这个吧

点击schema出现这个这个就是我们的文档，最上面的搜索，QUERIES是关于查询，MUTATIONS关于增加，随着左边的语句增加，右边文档增加，点开查询看看

现在带有感叹号的为必填，我们点开的是枚举类型，可以自行查看相关信息，再打开添加的试试

actor对应ActorType类型，里面由id,name属性

是不是感觉很方便

https://github.com/1045683477/GraphQL-
这是到现在的写的,代码在GitHub上