完全是本地开发的，我在这里遵循了该教程：https://scotch.io/tutorials/super-simple-graphql-with-node#toc-creating-the-graphql-server
几乎没有任何修改，只是将焦点限制在“产品”表上。没有“用户”或“配方”表。
看来我现在唯一的问题是从MySQL DB检索数据。
当然，我已经Google搜索并广泛比较了教程。我已经遍历了很多代码，以至于变得越来越模糊。
如果我将“ return”更改为{“ name”：“ test”}，则数据将完美地传递到我的本地GraphQL仪表板。
models / index.js
'use strict';
const fs = require('fs');
const path = require('path');
const Sequelize = require('sequelize');
const basename = path.basename(__filename);
const env = process.env.NODE_ENV || 'development';
const config = require(__dirname + '/../config/config.json')[env];
const db = {};
let sequelize;
if (config.use_env_variable) {
sequelize = new Sequelize(process.env[config.use_env_variable], config);
} else {
sequelize = new Sequelize(config.database, config.username, config.password, config);
}
fs.readdirSync(__dirname).filter(file => {
return (file.indexOf('.') !== 0) && (file !== basename) && (file.slice(-3) === '.js');
}).forEach(file => {
const model = sequelize['import'](path.join(__dirname, file));
db[model.name] = model;
}); //console.log(db); Object.keys(db).forEach(modelName => { if (db[modelName].associate) { db[modelName].associate(db); } }); db.sequelize = sequelize; db.Sequelize = Sequelize;
module.exports = db;
'use strict';
module.exports = (sequelize, DataTypes) => {
const Product = sequelize.define('Product', {
name: DataTypes.STRING,
urlWordRef: DataTypes.STRING,
seoTitle: DataTypes.STRING,
seoDescription: DataTypes.STRING,
standardEquipment: DataTypes.STRING,
technicalSpecs: DataTypes.STRING
}, {});
Product.associate = function(models) {
// associations can be defined here
//Product.hasMany(models.RefProductOptions)
};
return Product;
};
// src/resolvers.js
const resolvers = {
Query: {
async products (root, { id }, { models }) {
return models.Products.findById(id) // *** THE LINE OF CODE WHICH FAILS ***
return {"name":"test"} // ** SUBSTITUTING THE ABOVE LINE WITH THIS - SUCCESS! ***
}
}
}
module.exports = resolvers
// src/schema.js
const { gql } = require('apollo-server')
const typeDefs = gql `
type Products {
id: Int!
name: String
urlWordRef: String
seoTitle: String
seoDescription: String
standardEquipment: String
technicalSpecs: String
}
type Query {
products(id: Int!): Products
}
`;
module.exports = typeDefs
// src/index.js
const { ApolloServer } = require('apollo-server')
const typeDefs = require('./schema')
const resolvers = require('./resolvers')
const models = require('../models')
const server = new ApolloServer({
typeDefs,
resolvers,
context: { models }
})
server.listen({port: 4000}).then(({ url }) => console.log('Server is running on localhost:4000'))
通过仪表板查询GraphQL：
{
products(id: 1) {
name
}
}
我希望我可以通过上面提到的GRaphQL查询传递ID，并获得正确的表行结果。
A，我准备用额头开始编码！
GraphQL中的错误响应：
{
"errors": [
{
"message": "Cannot read property 'findById' of undefined",
"locations": [
{
"line": 2,
"column": 3
}
],
"path": [
"products"
],
"extensions": {
"code": "INTERNAL_SERVER_ERROR",
"exception": {
"stacktrace": [
"TypeError: Cannot read property 'findById' of undefined",
" at products (/home/bob/graphql-server/src/resolvers.js:6:26)",
" at field.resolve (/home/bob/graphql-server/node_modules/graphql-extensions/dist/index.js:140:26)",
" at resolveFieldValueOrError (/home/bob/graphql-server/node_modules/graphql/execution/execute.js:486:18)",
" at resolveField (/home/bob/graphql-server/node_modules/graphql/execution/execute.js:453:16)",
" at executeFields (/home/bob/graphql-server/node_modules/graphql/execution/execute.js:294:18)",
" at executeOperation (/home/bob/graphql-server/node_modules/graphql/execution/execute.js:238:122)",
" at executeImpl (/home/bob/graphql-server/node_modules/graphql/execution/execute.js:85:14)",
" at Object.execute (/home/bob/graphql-server/node_modules/graphql/execution/execute.js:62:35)",
" at /home/bob/graphql-server/node_modules/apollo-server-core/dist/requestPipeline.js:239:46",
" at Generator.next (<anonymous>)",
" at /home/bob/graphql-server/node_modules/apollo-server-core/dist/requestPipeline.js:7:71",
" at new Promise (<anonymous>)",
" at __awaiter (/home/bob/graphql-server/node_modules/apollo-server-core/dist/requestPipeline.js:3:12)",
" at execute (/home/bob/graphql-server/node_modules/apollo-server-core/dist/requestPipeline.js:218:20)",
" at Object.<anonymous> (/home/bob/graphql-server/node_modules/apollo-server-core/dist/requestPipeline.js:156:42)",
" at Generator.next (<anonymous>)",
" at fulfilled (/home/bob/graphql-server/node_modules/apollo-server-core/dist/requestPipeline.js:4:58)",
" at <anonymous>",
" at process._tickCallback (internal/process/next_tick.js:188:7)"
]
}
}
}
],
"data": {
"products": null
}
}