php error saying "file_put_contents () failed to open stream"

Question

I'm new to php and I am using that to get my image to my computer from my app using flutter. When I open that php file on web, it says this error

Warning: file_put_contents(C: mpp\htdocslutter_testelse value): failed to open stream: No such file or directory in C:\xampp\htdocs\flutter_test\upload_image.php on line 9

So there is an error on line 9 and here is the php code

   <?php
 
    $image = isset($_POST['image']) ? $_POST['image'] : "else value";
    $name = isset($_POST['name']) ? $_POST['name'] : "else value";
 
 
    $realImage = base64_decode($image);
 
    // THIS IS LINE 9:
    file_put_contents("C:\xampp\htdocs\flutter_test".$name, $realImage);

    echo "Image Uploaded Greatly";
 
?>

And here is my flutter code for the app if necessary

import 'package:flutter/material.dart';
import 'dart:io';
import 'dart:convert';
import 'package:http/http.dart' as http;
import 'package:image_picker/image_picker.dart';

void main() {
  runApp(MyApp());
}

class MyApp extends StatelessWidget {
  @override
  Widget build(BuildContext context) {
    return MaterialApp(
      title: 'Upload Image Demo',
      theme: ThemeData(
        primarySwatch: Colors.blue,
        //visualDensity: VisualDensity.adaptivePlatformDensity,
      ),
      home: UploadImageDemo(),
    );
  }
}

class UploadImageDemo extends StatefulWidget {
  UploadImageDemo() : super();

  final String title = "Upload Image Demo";

  @override
  UploadImageDemoState createState() => UploadImageDemoState();
}

class UploadImageDemoState extends State<UploadImageDemo> {
  //
  static final String uploadEndPoint =
      'http://localhost/flutter_test/upload_image.php';
  Future<File> file;
  String status = '';
  String base64Image;
  File tmpFile;
  String errMessage = 'Error Uploading Image';

  chooseImage() {
    setState(() {
      file = ImagePicker.pickImage(source: ImageSource.gallery);
    });
    setStatus('');
  }

  setStatus(String message) {
    setState(() {
      status = message;
    });
  }

  startUpload() {

    setStatus('Uploading Image...');
    if (null == tmpFile) {
      setStatus(errMessage);
      return;
    }
    String fileName = tmpFile.path.split('/').last;
    upload(fileName);
    //print("MOIKKULI "+ fileName);
  }

  upload(String fileName) {
    http.post(uploadEndPoint, body: {
      "image": base64Image,
      "name": fileName,
    }).then((result) {
      setStatus(result.statusCode == 200 ? result.body : errMessage);
    }).catchError((error) {
      setStatus(error);
    });
  }

  Widget showImage() {
    return FutureBuilder<File>(
      future: file,
      builder: (BuildContext context, AsyncSnapshot<File> snapshot) {
        if (snapshot.connectionState == ConnectionState.done &&
            null != snapshot.data) {
          tmpFile = snapshot.data;
          base64Image = base64Encode(snapshot.data.readAsBytesSync());
          return Flexible(
            child: Image.file(
              snapshot.data,
              fit: BoxFit.fill,
            ),
          );
        } else if (null != snapshot.error) {
          return const Text(
            'Error Picking Image',
            textAlign: TextAlign.center,
          );
        } else {
          return const Text(
            'No Image Selected',
            textAlign: TextAlign.center,
          );
        }
      },
    );
  }

  @override
  Widget build(BuildContext context) {
    final size = MediaQuery.of(context).size;
    print(size);
    return Scaffold(
      appBar: AppBar(
        title: Text("Upload Image Demo"),
      ),
      body: Container(
        padding: EdgeInsets.all(30.0),
        child: Column(
          crossAxisAlignment: CrossAxisAlignment.stretch,
          children: <Widget>[
            OutlineButton(
              onPressed: chooseImage,
              child: Text('Choose Image'),
            ),
            SizedBox(
              height: 20.0,
            ),
            showImage(),
            SizedBox(
              height: 20.0,
            ),
            OutlineButton(
              onPressed: startUpload,
              child: Text('Upload Image'),
            ),
            SizedBox(
              height: 20.0,
            ),
            Text(
              status,
              textAlign: TextAlign.center,
              style: TextStyle(
                color: Colors.green,
                fontWeight: FontWeight.w500,
                fontSize: 20.0,
              ),
            ),
            SizedBox(
              height: 20.0,
            ),
          ],
        ),
      ),
    );
  }

I am using a XAMPP apache server for this project. How do I fix this php error?

Answer 1

The back slash \ is an "escape character" - it gives a different meaning to the character that follows it. That means when you write "C:\xampp\htdocs\flutter_test" what you get is something else.

One solution is to use single quotes instead of double quotes: 'C:\xampp\htdocs\flutter_test'. Inside single quotes, \x and \f don't have any special meaning, they stand for themselves.

Another solution is to use the escape charater to escape itself: "C:\\xampp\\htdocs\\flutter_test"

A third solution is to use the portable directory separator character / instead of windows-only \: "C:/xampp/htdocs/flutter_test"