[英]How to execute a mutation in GraphQL?
在 GraphQL 中,我们基本上有两种类型的操作:查询和突变。 虽然查询在文档中有很好的描述并且有很多示例,但我很难理解如何执行突变。 突变显然是更新方法。
我创建了非常简单的 Node.js 服务器:
var express = require("express");
var graphqlHTTP = require("express-graphql");
var graphql = require("graphql");
var inMemoryDatabase = require("./inMemoryDatabase").inMemoryDatabase;
var _ = require("lodash-node");
var userType = new graphql.GraphQLObjectType({
name: "User",
fields: {
id: { type: graphql.GraphQLString },
name: { type: graphql.GraphQLString }
}
});
var queryType = new graphql.GraphQLObjectType({
name: "Query",
fields: {
user: {
type: userType,
args: {
id: { type: graphql.GraphQLString }
},
resolve: function(parent, { id }) {
return _.find(inMemoryDatabase, { id: id });
}
}
}
});
var mutationType = new graphql.GraphQLObjectType({
name: "Mutation",
fields: {
user: {
type: userType,
args: {
id: { type: graphql.GraphQLString },
name: { type: graphql.GraphQLString }
},
resolve: function(parent, { id, name }) {
var index = _.findIndex(inMemoryDatabase, { id: id });
inMemoryDatabase.splice(index, 1, { id: id, name: name });
return _.find(inMemoryDatabase, { id: id });
}
}
}
});
var schema = new graphql.GraphQLSchema({
query: queryType,
mutation: mutationType
});
var app = express();
app.use(
"/graphql",
graphqlHTTP({
schema: schema,
graphiql: true
})
);
var port = 9000;
if (process.env.PORT) {
port = process.env.PORT;
}
app.listen(port);
console.log("Running a GraphQL API server at localhost:" + port + "/graphql");
在 memory 数据库中只是一个用户对象数组{id, name}
:
var inMemoryDatabase = [
{
id: "31ce0260-2c23-4be5-ab78-4a5d1603cbc8",
name: "Mark"
},
{
id: "2fb6fd09-2697-43e2-9404-68c2f1ffbf1b",
name: "Bill"
}
];
module.exports = {
inMemoryDatabase
};
执行查询以通过 id 获取用户如下所示:
{
user(id: "31ce0260-2c23-4be5-ab78-4a5d1603cbc8"){
name
}
}
改变用户名的突变会是什么样子?
嘿,您可能完全错过了您所说的内容,但是我看待突变的方式是这样的
type
中指定的type
var mutationType = new graphql.GraphQLObjectType({ name: "Mutation", fields: { user: { // You must return something from your resolve function // that will fulfill userType requirements type: userType, // with these arguments, find the user and update them args: { id: { type: graphql.GraphQLString }, name: { type: graphql.GraphQLString } }, // this does the lookup and change of the data // the last step of your result is to return something // that will fulfill the userType interface resolve: function(parent, { id, name }) { // Find the user, Update it // return something that will respond to id and name, probably a user object } } } });
然后将其作为上下文,传递一些参数并请求返回用户
mutation updateUser {
user(id: "1", name: "NewName") {
id
name
}
}
在正常的生产模式中,通常还会有类似errors
,这些errors
可能会返回以传达失败/未找到的更新的不同状态
@Austio的答案非常接近,但是正确的方法是:
mutation updateUser {
user(id: "31ce0260-2c23-4be5-ab78-4a5d1603cbc8", name: "Markus") {
id
name
}
}
如果我们直接与下面的 MongoDB 联系,将会对您有所帮助。
mutation {
taskTrackerCreateOne
(
record:
{
id:"63980ae0f019789eeea0cd33",
name:"63980c86f019789eeea0cda0"
}
)
{
recordId
}
}
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