fcf.NLock.lockFile() function
[SERVER ONLY]
fcf.NLock.lockFile (string a_filePath, function a_cb)
[SERVER ONLY]
fcf.NLock.lockFile (number a_fileHandle, function a_cb)
Package: fcf-framework-lock
File: fcf-framework-lock:index.js
Available from version: 1.0.0
Performs file locking using the flock or LockFileEx function
Arguments
- The path to the file.
- The open file handle returned by the FS.open() functions
- The function of processing the result of the function execution
Function signature: a_cb(
-
Error |undefined a_error - If the function executed with an error, then the argument contains an error object -
number a_lock - Contains a lock handle to be passed to theunlockFile function to unlock the file.
Example: Locking when using a file path
const libLock = require("fcf-framework-lock");
function action(a_name) {
console.log(`Action ${a_name}: Start locking file...`);
libLock .lockFile ("index.js", (a_error, a_lock)=>{
if (a_error){
console.log("Error lock on file");
process.exit(1);
}
console.log(`Action ${a_name}: We do some action`);
setTimeout(()=>{
console.log(`Action ${a_name}: Removing a lock from a file`);
libLock .unlockFile (a_lock, (a_error)=>{
if (a_error){
console.log("Error unlock on file");
process.exit(1);
}
});
}, 1000);
})
}
action("1");
action("2");
Output:
Action 1: Start locking file...
Action 2: Start locking file...
Action 1: We do some action
Action 1: Removing a lock from a file
Action 2: We do some action
Action 2: Removing a lock from a file
Example: Locking when using a file handle
let libFS = require("fs");
let libUtil = require("util");
let libLock = require("fcf-framework-lock");
async function action(a_name) {
let file, lock;
await new Promise((a_res)=>{a_res();})
.then(async ()=>{
console.log(`Action ${a_name}: Start locking file...`);
file = await libUtil.promisify(libFS.open)("index.js", "r");
lock = await libUtil.promisify(libLock .lockFile )(file);
console.log(`Action ${a_name}: We do some action`);
await new Promise((a_res, a_rej)=>{
setTimeout(()=>{
a_res();
}, 1000);
});
})
.finally(async ()=>{
if (lock) {
console.log(`Action ${a_name}: Removing a lock from a file`);
await libUtil.promisify(libLock .unlockFile )(lock);
}
})
.finally(async ()=>{
if (file) {
await libUtil.promisify(libFS.close)(file);
}
});
}
action("1");
action("2");
Output:
Action 1: Start locking file...
Action 2: Start locking file...
Action 1: We do some action
Action 1: Removing a lock from a file
Action 2: We do some action
Action 2: Removing a lock from a file
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