Issue with Fetching Files in React – Getting 'Failed to Fetch' Error

[Masterbetier]

Help with Fetching Files in React

Hi everyone,

I'm working on a React app where I'm trying to fetch files from a backend server. However, I'm encountering an issue where the fetch call fails, and I receive the following error message in the console:

Here's the relevant code:

import { useState, useEffect } from "react"
import { Table, TableHeader, TableBody, TableHead, TableRow, TableCell } from "@/components/ui/table"

interface File {
  name: string
  path: string
}

export default function Home() {
  const [files, setFiles] = useState<File[]>([])
  const [error, setError] = useState<string | null>(null)
  const [isLoading, setIsLoading] = useState(true)

  useEffect(() => {
    const fetchFiles = async () => {
      setIsLoading(true)
      try {
        console.log("Fetching files...")
        const response = await fetch("http://localhost:5000/api/files")
        console.log("Response received:", response)
        if (!response.ok) {
          throw new Error(`HTTP error! status: ${response.status}`)
        }
        const data = await response.json()
        console.log("Data received:", data)
        setFiles(data)
      } catch (e) {
        console.error("Error fetching files:", e)
        setError(`Failed to fetch files: ${e.message}. Please check if the backend server is running.`)
      } finally {
        setIsLoading(false)
      }
    }

    fetchFiles()
  }, [])

  if (isLoading) {
    return <div className="container mx-auto p-4">Cargando...</div>
  }

  if (error) {
    return <div className="container mx-auto p-4 text-red-500">{error}</div>
  }

  return (
    <div className="container mx-auto p-4">
      <h1 className="text-2xl font-bold mb-4">Archivos en el Escritorio</h1>
      {files.length > 0 ? (
        <Table>
          <TableHeader>
            <TableRow>
              <TableHead>Nombre</TableHead>
              <TableHead>Ruta</TableHead>
            </TableRow>
          </TableHeader>
          <TableBody>
            {files.map((file, index) => (
              <TableRow key={index}>
                <TableCell>{file.name}</TableCell>
                <TableCell>{file.path}</TableCell>
              </TableRow>
            ))}
          </TableBody>
        </Table>
      ) : (
        <p>No se encontraron archivos.</p>
      )}
    </div>
  )
}

What I've tried:
I checked if the backend server is running on http://localhost:5000, but I still receive the error.
I made sure that the fetch URL is correct.

[CesarG503]

Response to "Issue with Fetching Files in React – Getting 'Failed to Fetch' Error"

Hi!

The "Failed to fetch" error you are encountering could be caused by several factors. Here are some steps and checks to help you debug the issue:

1. Check the Backend Server

• Ensure that your backend server running at http://localhost:5000 is up and running. You can check this by accessing http://localhost:5000/api/files directly in your browser or using a tool like Postman to see if the API is responding correctly.

• If the server isn't running, make sure to start it before making requests from the frontend.

2. CORS Issues

• If your backend is running on a different port (like 5000) while your React app is running on another (like 3000), CORS (Cross-Origin Resource Sharing) could be blocking the request.

• To fix this, you may need to enable CORS on your backend. For example, if you're using Express, you can use the cors middleware:

  const cors = require('cors');
  app.use(cors());

3. Network Errors

• If the fetch call isn't reaching the backend, check the network tab in your browser's developer tools (F12) for any network errors. This can give you more insights into why the request is failing.

4. Error Handling

• Your catch block is logging the error message correctly, but to make sure it's an issue with the fetch request and not something else, try logging the response object before the throw statement to check the status code:

  console.log('Response Status:', response.status);
  if (!response.ok) {
    throw new Error(`HTTP error! Status: ${response.status}`);
  }

5. Server Logs

• Check the logs of your backend server to see if there are any errors or issues when trying to process the request.

6. Use console.log() for Debugging

• Add more logging to your fetch request to ensure that the issue is not on the frontend side. You can log the request headers and the full response object.

  console.log('Request URL:', 'http://localhost:5000/api/files');
  console.log('Request Options:', { method: 'GET' });

7. Ensure Proper Backend Response

• Make sure that the backend is returning valid JSON data. You can test this by logging the response body before processing it:

  const data = await response.json();
  console.log('Backend Response:', data);

By going through these checks, you should be able to pinpoint where the issue is coming from. If you're still facing the issue after these steps, feel free to share more details, and I can assist further.

Good luck with debugging!