如何解决reactjs 与核心 3.1 api 控制器获取json错误而不是返回数据
我正在创建一个登录表单并尝试为会话状态取回数据。我收到错误“Uncaught (in promise) SyntaxError: Unexpected token
Login.js file
import React,{ Component } from 'react';
import { Header } from './Header';
class Login extends Component {
constructor(props) {
super(props);
this.state = { fields: { "idAccount": 0,"idAccountUser": 0,"UserFirstName": "","UserLastName": "","UserEmail": "","UserCulture": "","AllowContentDistribution": false },errors: {} };
this.state = { inputFields: { "userName": "","password": "" } };
}
authenticateUser(e) {
e.preventDefault();
var userName = e.userName;
var password = e.password;
if (this.handleValidation()) {
fetch("Http://localhost:1234/api/CustomerManager/AuthenticateUser?UserName=" + userName +
"&Password=" + password,{
method: "GET",headers: {
contentType: "application/json; charset=utf-8",accept: 'application/json'
},})
.then((response) => {
response.json();
})
.then((data) => {
this.state.fields = data;
console.log(data);
console.log("idAccount: {0},UserFirstName: {1},UserLastName: {2}",this.state.fields["idAccount"],this.state.fields["UserFirstName"],this.state.fields["UserLastName"]);
})
.catch((error) => {
console.log('error: ' + error);
});
}
else {
console.log('error: ' + this.state.errors);
}
};
handleValidation() {
let fields = this.state.inputFields;
let errors = {};
let formIsValid = true;
//UserName
if (!fields["userName"]) {
formIsValid = false;
errors["userName"] = "UserName Cannot be empty";
}
//Password
if (!fields["password"]) {
formIsValid = false;
errors["password"] = "Password Cannot be empty";
}
this.setState({ errors: errors });
return formIsValid;
};
handleChange(field,e) {
let fields = this.state.inputFields;
fields[field] = e.target.value;
this.setState({ fields });
};
render() {
return (
<>
<Header />
<div className="login center">
<form
onSubmit={this.authenticateUser.bind(this)}
>
<div>
<label htmlFor="userName">
Username:
</label>
</div>
<div>
<input
id="userName"
onChange={this.handleChange.bind(this,"userName")} value=
{this.state.inputFields["userName"]}
/>
</div>
<div>
<label htmlFor="password">
Password (case-sensitive):
</label>
</div>
<div>
<input
id="password"
type="password"
onChange={this.handleChange.bind(this,"password")} value=
{this.state.inputFields["password"]}
/>
</div>
<div>
<button className="Button ActionButton">Sign In</button>
</div>
</form>
</div>
</>
);
};
}
export default Login
Controller
[HttpGet]
public IHttpActionResult AuthenticateUser(string userName,string password)
{
try
{
Login.AuthenticateUser(userName,password);
SessionState sessionState = new SessionState
{
IdAccount = IdAccount,IdAccountUser = IdAccountUser,UserFirstName = UserFirstName,UserLastName = UserLastName,UserEmail = UserEmail,UserCulture = UserCulture,};
return Ok(sessionState);
}
catch (Exception ex)
{
// show the error
return InternalServerError(ex);
}
}
解决方法
基本上，问题出在响应类型上，我在我身边测试过，id确实有效。您的 login.js 中存在一些错误，但与您的错误无关。
根据我的搜索，我发现 IHttpActionResult 是一个不是 existed in Core 的接口，如果您的 web api 项目在 asp.net core 中，您需要使用 IActionResult。我还建议使用 asp.net core 而不是 asp.net。顺便说一句，如果仍然无法得到json响应，您可以参考this section在您的方法中添加过滤器[Produces("application/json")]。
登录.js
import React,{ Component } from 'react';
class Login extends Component {
constructor(props) {
super(props);
this.state = { fields: { "idAccount": 0,"idAccountUser": 0,"UserFirstName": "","UserLastName": "","UserEmail": "","UserCulture": "","AllowContentDistribution": false
},errors: {},inputFields: { "userName": "","password": "" }
};
}
authenticateUser(e) {
e.preventDefault();
var userName = this.state.inputFields.userName;
var password = this.state.inputFields.password;
const res = fetch("https://localhost:44325/api/CustomerManager/AuthenticateUser?UserName=" + userName + "&Password=" + password,{
method: "GET",headers: {
contentType: "application/json; charset=utf-8",accept: 'application/json'
},})
.then(res =>res.json())
.then((data) => {
console.log(data);
console.log("msg is :"+data.msg);
})
.catch((error) => {
console.log('error: ' + error);
});
};
handleChange(field,e) {
let fields = this.state.inputFields;
fields[field] = e.target.value;
this.setState({ fields });
};
render() {
return (
<>
{/* <Header /> */}
<div className="login center">
<form
onSubmit={this.authenticateUser.bind(this)}
>
<div>
<label htmlFor="userName">
Username:
</label>
</div>
<div>
<input
id="userName"
onChange={this.handleChange.bind(this,"userName")} value=
{this.state.inputFields["userName"]}
/>
</div>
<div>
<label htmlFor="password">
Password (case-sensitive):
</label>
</div>
<div>
<input
id="password"
type="password"
onChange={this.handleChange.bind(this,"password")} value=
{this.state.inputFields["password"]}
/>
</div>
<div>
<button className="Button ActionButton">Sign In</button>
</div>
</form>
</div>
</>
);
};
}
export default Login
这是我的控制器，在 asp.net core3.1 中：
using Microsoft.AspNetCore.Mvc;
namespace test0715.Controllers
{
public class AuthController : Controller
{
[Route("/api/CustomerManager/AuthenticateUser")]
public IActionResult Index(string UserName,string Password)
{
SessionState ss = new SessionState
{
age = 18,name = "test"
};
return Ok(ss);
}
}
public class SessionState {
public int age { get; set; }
public string name { get; set; }
}
}
如果您在 asp.net 中编写 api，您可以看到下面的示例。在这里，如果我调用http://localhost:53148/api/auth?name=aa&psd=bb，我会得到xml响应，而我在login.js中调用它，我会得到json响应。
using System.Web.Http;
using System.Web.Http.Cors;
namespace WebApplication1.Controllers
{
[EnableCors(origins: "*",headers: "*",methods: "*")]
public class AuthController : ApiController
{
[HttpGet]
public IHttpActionResult Get(string name,string psd)
{
Product product = new Product
{
age = 18,name = "hello"
};
return Ok(product); // Returns an OkNegotiatedContentResult
}
}
public class Product {
public int age { get; set; }
public string name { get; set; }
}
}
App_start->webapiconfig.cs
using System.Web.Http;
namespace WebApplication1
{
public static class WebApiConfig
{
public static void Register(HttpConfiguration config)
{
config.EnableCors();
// Web API configuration and services
// Web API routes
config.MapHttpAttributeRoutes();
config.Routes.MapHttpRoute(
name: "DefaultApi",routeTemplate: "api/{controller}/{id}",defaults: new { id = RouteParameter.Optional }
);
}
}
}
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