How do you dynamically observe files in a directory and log a new file as it appears

[trookie2000]

I'm new to rust, and the feature I want to implement is to watch the folder under "D:/ working directory /tools" and whenever a new file appears, return a line of text to the front-end textarea with id=log_content.

But my code is not doing my job correctly. It just outputs a log line when the program runs. How can I change that?
(The backend uses rust+tauri,Front-end html+css+js)
The code is as follows：

1.The get_log function:

|

2.discoroboy.html:

[trookie2000]

get_log

#[command]
async fn get_log(id: i32) -> Option {

let content = fs::read_to_string("D:/code/rust/robot/src-tauri/src/config_file/ErrorTypeList.xml").expect("error");


let parser = EventReader::from_str(&content);
let mut is_parsing_log = false;
let mut log = String::new();

for e in parser {
    match e {
        Ok(XmlEvent::StartElement {
            name, attributes, ..
        }) => {
            let element_name = name.local_name.to_string();
            if element_name.starts_with("ErrorInfo4") {
               
                is_parsing_log = true;
            }
        }
        Ok(XmlEvent::EndElement { name }) => {
            if is_parsing_log {
                is_parsing_log = false;
                
                log.push('\n');
            }
        }
        Ok(XmlEvent::Characters(content)) => {
            if is_parsing_log {
             
                let current_time = Local::now();

                
                let time_str = current_time.format("%Y-%m-%d %H:%M:%S").to_string();

                
                
                log.push_str(&format!("[{}] {}\n", time_str, content));
                
                let mut watcher = notify::recommended_watcher(|res| {
                    match res {
                        Ok(event) => println!("event: {:?}", event),                          
                        Err(e) => println!("watch error: {:?}", e),
                    }
                }).ok()?;
        
                let directory_path = "D:/工作目录/tools";
        
                // Add a path to be watched. All files and directories at that path and
                // below will be monitored for changes.
                watcher
                    .watch(Path::new(directory_path), RecursiveMode::Recursive)
                    .ok()?;
            }
        }
        _ => {}
    }
}

Some(log)
}

discorobot.html

<textarea class="textarea" id="logContent"></textarea>

    invoke('get_log', { skillInfo: response, id: id })
        .then((logResponse) => {
            console.log('Log Response:', logResponse);

           
            const logTextarea = document.getElementById("logContent");
            logTextarea.readOnly = true;
            logTextarea.value = logResponse;
        })
        .catch((error) => {
            console.error('Error calling get_log:', error);
        });