Im getting this error when I try to fetch data from webapi to display in react js Here is a photo when I check the console this is what I get
here is my program.cs
using WebApp.Data;
var myAllowSpecificOrigins = "_myAllowSpecificOrigins";
var builder = WebApplication.CreateBuilder(args);
// Add services to the container.
builder.Services.AddControllers();
// Learn more about configuring Swagger/OpenAPI at https://aka.ms/aspnetcore/swashbuckle
builder.Services.AddEndpointsApiExplorer();
builder.Services.AddSwaggerGen();
builder.Services.AddDbContext<DataContext>(options =>
{
options.UseSqlServer(builder.Configuration.GetConnectionString("DefaultConnection"));
});
//Enable CORS
builder.Services.AddCors(options =>
{
options.AddPolicy(name: myAllowSpecificOrigins,
builder =>
{
builder.WithOrigins("http://localhost:3000/")
.AllowAnyMethod()
.AllowAnyHeader();
});
});
var app = builder.Build();
// Configure the HTTP request pipeline.
if (app.Environment.IsDevelopment())
{
app.UseSwagger();
app.UseSwaggerUI();
}
app.UseHttpsRedirection();
app.UseCors(myAllowSpecificOrigins);
app.UseAuthorization();
app.MapControllers();
app.Run();
here is one of my files employee.js
import {variables} from './variables.js';
export class Employee extends Component{
constructor(props){
super(props);
this.state={
departments:[],
employees:[],
modalTitle:"",
EmployeeId:0,
EmployeeName:"",
Department:"",
DateOfJoining:"",
}
}
refreshList(){
fetch(variables.API_URL+'employees')
.then(response=>response.json())
.then(data=>{
this.setState({employees:data});
});
fetch(variables.API_URL+'department')
.then(response=>response.json())
.then(data=>{
this.setState({departments:data});
});
}
componentDidMount(){
this.refreshList();
}
changeEmployeeName =(e)=>{
this.setState({EmployeeName:e.target.value});
}
changeDepartment =(e)=>{
this.setState({Department:e.target.value});
}
changeDateOfJoining =(e)=>{
this.setState({DateOfJoining:e.target.value});
}
addClick(){
this.setState({
modalTitle:"Add Employee",
EmployeeId:0,
EmployeeName:"",
Department:"",
DateOfJoining:"",
PhotoFileName:"anonymous.png"
});
}
editClick(emp){
this.setState({
modalTitle:"Edit Employee",
EmployeeId:emp.EmployeeId,
EmployeeName:emp.EmployeeName,
Department:emp.Department,
DateOfJoining:emp.DateOfJoining,
PhotoFileName:emp.PhotoFileName
});
}
createClick(){
fetch(variables.API_URL+'employee',{
method:'POST',
headers:{
'Accept':'application/json',
'Content-Type':'application/json'
},
body:JSON.stringify({
EmployeeName:this.state.EmployeeName,
Department:this.state.Department,
DateOfJoining:this.state.DateOfJoining,
PhotoFileName:this.state.PhotoFileName
})
})
.then(res=>res.json())
.then((result)=>{
alert(result);
this.refreshList();
},(error)=>{
alert('Failed');
})
}
updateClick(){
fetch(variables.API_URL+'employee',{
method:'PUT',
headers:{
'Accept':'application/json',
'Content-Type':'application/json'
},
body:JSON.stringify({
EmployeeId:this.state.EmployeeId,
EmployeeName:this.state.EmployeeName,
Department:this.state.Department,
DateOfJoining:this.state.DateOfJoining,
PhotoFileName:this.state.PhotoFileName
})
})
.then(res=>res.json())
.then((result)=>{
alert(result);
this.refreshList();
},(error)=>{
alert('Failed');
})
}
deleteClick(id){
if(window.confirm('Are you sure?')){
fetch(variables.API_URL+'employee/'+id,{
method:'DELETE',
headers:{
'Accept':'application/json',
'Content-Type':'application/json'
}
})
.then(res=>res.json())
.then((result)=>{
alert(result);
this.refreshList();
},(error)=>{
alert('Failed');
})
}
}
imageUpload=(e)=>{
e.preventDefault();
const formData=new FormData();
formData.append("file",e.target.files[0],e.target.files[0].name);
fetch(variables.API_URL+'employee/savefile',{
method:'POST',
body:formData
})
.then(res=>res.json())
.then(data=>{
this.setState({PhotoFileName:data});
})
}
render(){
const {
departments,
employees,
modalTitle,
EmployeeId,
EmployeeName,
Department,
DateOfJoining,
PhotoPath,
PhotoFileName
}=this.state;
return(
<div>
<button type="button"
className="btn btn-primary m-2 float-end"
data-bs-toggle="modal"
data-bs-target="#exampleModal"
onClick={()=>this.addClick()}>
Add Employee
</button>
<table className="table table-striped">
<thead>
<tr>
<th>
EmployeeId
</th>
<th>
EmployeeName
</th>
<th>
Department
</th>
<th>
DOJ
</th>
<th>
Options
</th>
</tr>
</thead>
<tbody>
{employees.map(emp=>
<tr key={emp.EmployeeId}>
<td>{emp.EmployeeId}</td>
<td>{emp.EmployeeName}</td>
<td>{emp.Department}</td>
<td>{emp.DateOfJoining}</td>
<td>
<button type="button"
className="btn btn-light mr-1"
data-bs-toggle="modal"
data-bs-target="#exampleModal"
onClick={()=>this.editClick(emp)}>
<svg xmlns="http://www.w3.org/2000/svg" width="16" height="16" fill="currentColor" className="bi bi-pencil-square" viewBox="0 0 16 16">
<path d="M15.502 1.94a.5.5 0 0 1 0 .706L14.459 3.69l-2-2L13.502.646a.5.5 0 0 1 .707 0l1.293 1.293zm-1.75 2.456-2-2L4.939 9.21a.5.5 0 0 0-.121.196l-.805 2.414a.25.25 0 0 0 .316.316l2.414-.805a.5.5 0 0 0 .196-.12l6.813-6.814z"/>
<path fillRule="evenodd" d="M1 13.5A1.5 1.5 0 0 0 2.5 15h11a1.5 1.5 0 0 0 1.5-1.5v-6a.5.5 0 0 0-1 0v6a.5.5 0 0 1-.5.5h-11a.5.5 0 0 1-.5-.5v-11a.5.5 0 0 1 .5-.5H9a.5.5 0 0 0 0-1H2.5A1.5 1.5 0 0 0 1 2.5v11z"/>
</svg>
</button>
<button type="button"
className="btn btn-light mr-1"
onClick={()=>this.deleteClick(emp.EmployeeId)}>
<svg xmlns="http://www.w3.org/2000/svg" width="16" height="16" fill="currentColor" className="bi bi-trash-fill" viewBox="0 0 16 16">
<path d="M2.5 1a1 1 0 0 0-1 1v1a1 1 0 0 0 1 1H3v9a2 2 0 0 0 2 2h6a2 2 0 0 0 2-2V4h.5a1 1 0 0 0 1-1V2a1 1 0 0 0-1-1H10a1 1 0 0 0-1-1H7a1 1 0 0 0-1 1H2.5zm3 4a.5.5 0 0 1 .5.5v7a.5.5 0 0 1-1 0v-7a.5.5 0 0 1 .5-.5zM8 5a.5.5 0 0 1 .5.5v7a.5.5 0 0 1-1 0v-7A.5.5 0 0 1 8 5zm3 .5v7a.5.5 0 0 1-1 0v-7a.5.5 0 0 1 1 0z"/>
</svg>
</button>
</td>
</tr>
)}
</tbody>
</table>
<div className="modal fade" id="exampleModal" tabIndex="-1" aria-hidden="true">
<div className="modal-dialog modal-lg modal-dialog-centered">
<div className="modal-content">
<div className="modal-header">
<h5 className="modal-title">{modalTitle}</h5>
<button type="button" className="btn-close" data-bs-dismiss="modal" aria-label="Close"
></button>
</div>
<div className="modal-body">
<div className="d-flex flex-row bd-highlight mb-3">
<div className="p-2 w-50 bd-highlight">
<div className="input-group mb-3">
<span className="input-group-text">Emp Name</span>
<input type="text" className="form-control"
value={EmployeeName}
onChange={this.changeEmployeeName}/>
</div>
<div className="input-group mb-3">
<span className="input-group-text">Department</span>
<select className="form-select"
onChange={this.changeDepartment}
value={Department}>
{departments.map(dep=><option key={dep.DepartmentId}>
{dep.DepartmentName}
</option>)}
</select>
</div>
<div className="input-group mb-3">
<span className="input-group-text">DOJ</span>
<input type="date" className="form-control"
value={DateOfJoining}
onChange={this.changeDateOfJoining}/>
</div>
</div>
<div className="p-2 w-50 bd-highlight">
<img width="250px" height="250px"
src={PhotoPath+PhotoFileName}/>
<input className="m-2" type="file" onChange={this.imageUpload}/>
</div>
</div>
{EmployeeId==0?
<button type="button"
className="btn btn-primary float-start"
onClick={()=>this.createClick()}
>Create</button>
:null}
{EmployeeId!=0?
<button type="button"
className="btn btn-primary float-start"
onClick={()=>this.updateClick()}
>Update</button>
:null}
</div>
</div>
</div>
</div>
</div>
)
}
}
I believe the issue has to deal with the CORS Policy, but have tried everything. Does anything stand out to anyone? What should I do to prevent this and to display data from webapi to react?
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Answer
you have to remove a trailing “/”, should be
builder.WithOrigins("http://localhost:3000")