How to locate local files in javascript

The arrival of the digital age has brought more convenience to individuals or businesses, but it has also caused various problems, such as privacy leaks, file loss, etc. For some sensitive data, such as company financial statements, customer information, etc., many companies do not want to store it in the cloud, but choose to store it locally. The location of local files needs to be located and accessed in the browser, and this article will introduce how to use JavaScript to locate the location of local files.

First, create a file input box in HTML, using the <input type="file"> tag like this:

<input type="file" id="fileInput">

Once the user selects Once you have a file, you can add it to a global variable so you can access it later in your code. You can use JavaScript's FileReader object to read files and obtain file contents.

let selectedFile;

document.getElementById('fileInput').addEventListener('change', (event) => {
  selectedFile = event.target.files[0];
  console.log(selectedFile);
});

When the user selects a file, the change event will be triggered, which will allow us to access the information of the selected file. We pass the event object as a parameter to the event handler and then access the event.target.files array, which contains all the files selected by the user. Here we select only the first file selected by the user and assign it to the selectedFile variable. Finally, we print the selectedFile object to the console to ensure the correct file has been selected.

Now that we have selected the local file and saved it to a global variable, the next task is to determine the path where it is located. Getting the path to a local file in JavaScript is often not possible because web browsers do not allow access to the full path of the user's local file system due to security concerns. However, we can generate a URL that can access the selected file by using the File API's URL.createObjectURL() function. This URL is unique and different from any other file or URL uploaded by the user and can be used as a unique ID to store the file or use it for other purposes.

Now, we can get the URL of the selected file with the following code:

const fileURL = URL.createObjectURL(selectedFile);

Now, we have a unique URL that can be used to access the file, but how do we determine which file the file is located in Clip path? In fact, this is impossible because JavaScript cannot access the user's local file system. When we use the URL.createObjectURL() function, the browser will automatically create a virtual file path for accessing the selected file. So, we might know the file's name, type, and contents, but we don't know the folder path where it resides. If we need to access the folder path, we need to ask the user to provide that information. For example, we could require the user to follow the file name with the folder path so that when the file is stored it is added to the correct folder.

To sum up, JavaScript cannot directly access the user's local file system, but we can use the FileReader object and the URL.createObjectURL() function to read the user Select a file and generate a unique URL to access the file's contents in a web application. If we need to access a folder path, we need to get that information from the user, for example by asking the user to follow the file name with the folder path.

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