当前位置：网站首页>[node learning notes] the chokidar module realizes file monitoring

[node learning notes] the chokidar module realizes file monitoring

2022-07-07 02:35:00 【51CTO】

Preface

When developing cloud disk , Used Node.js Of chokidar The module monitors local files , Get the trigger event of file modification , Now let's introduce the knowledge points involved and the implementation process .

Knowledge point

chokidar.watch(paths, [options]) Return to one chokidar Construct listening instance
Parameters ：paths
A string or an array , Describe the path of the monitored file or folder .

Event response

.add Triggered when adding a file

.addDir Triggered when adding a folder

.unlink Delete the corresponding file

.unlinkDir Delete the corresponding folder

.change Triggered when the file content changes

.all（ except ready, raw, and error All event types except ） contain ：add、addDir、unlink、unlinkDir、change

.ready Initialization complete

.raw Original event

.error Capture error

.unwatch(path / paths) Stop listening for incoming files / Folder

.close() Remove from the monitoring file / Close all listeners

.getWatched() Back here FSWatcher Objects of all paths on the file system being monitored by the instance

Sample code of listening file

       
       import chokidar from "chokidar";
       
import { ipcRenderer } from "electron";
       
import fs from "fs";
       
let watcher: any = null;
       
export const addFileToWatcher = (localPath: string) => {
       
    if (watcher) {
       
        watcher.add(localPath);
       
    } else {
       
        watcher = chokidar.watch(localPath);
       
        watcher.on("all", (event: any, path: string) => {
       
            // Monitoring except ready, raw, and error All event types except 
       
            console.log(event, path);
       
        });
       
        watcher.on("ready", (path: string) => {
       
            console.log("ready", path);
       
        });
       
        watcher.on("add", (path: string) => {
       
            console.log(" Add monitoring ", path);
       
            console.log(watcher.getWatched());
       
        });
       
        watcher.on("change", (path: string) => {
       
            const token = localStorage.getItem("token");
       
            console.log(" monitor + File update :" + path);
       
            ipcRenderer.send("fileChange", path.replaceAll("\\", "/"), token);
       
        });
       
        watcher.on("unlink", (path: string) => {
       
            watcher.unwatch(path);
       
            if (fs.existsSync(path)) {
       
                watcher.add(path);
       
                const token = localStorage.getItem("token");
       
                console.log(" file save :" + path);
       
                ipcRenderer.send("fileChange", path.replaceAll("\\", "/"), token);
       
            }
       
        });
       
    }
       
};
       
export const removeFileWathcer = (localPath: string) => {
       
    console.log('watcher',watcher)
       
    if (watcher) {
       
        console.log(" Remove monitor -", localPath);
       
        watcher.unwatch(localPath);
       
    }
       
};
       
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matters needing attention

When realizing file listening , There is a problem of system compatibility , Some computers will not trigger file modification change, It triggered unlink The circumstances of the incident . therefore , stay unlink Added in the event , Trigger update when file exists .

That's what this issue is about chokidar The module realizes local file listening The share of , I hope I can help you .

In the next issue, I'll share more details about the actual combat , If you're interested in that , Welcome to pay attention to 、 Leaving a message. , Your support is my motivation ！

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