#### Table of contents
- File Lockdown
- Installation
- Basic Usage
- How It Works
- Key Features
- Config Sets
- Reference
- lockFile
- lockReadFile
- lockWriteFile
- lockReadWriteFile
- lockAppendFile
- lockDeleteFile
- lockRename
- lockCreateDir
- lockDeleteDir
- lockAccess
- License
# File Lockdown
File Lockdown is a library designed to handle file locking and asynchronous file operations.
It is built for use with
fs-broker
and allows communication with background processes via the net-fn
module.
The library ensures thread safety and provides a robust API for managing file operations without blocking the event loop.
This manual is also available in HTML5 format.
---
## Installation
Install the library using npm:
npm install file-lockdown
---
## Basic Usage
Here’s a simple example of how to use the library:
javascript
var file_lock = require("file-lockdown");
setTimeout(function () {
file_lock.lockAppendFile("./test.txt", "1 test\r\n", function (err) {
if (err) { console.error(err); }
});
}, 100);
---
## How It Works
The library uses a locking mechanism to ensure that file operations are serialized for the same file. This prevents race conditions and ensures thread safety.
1. A lockFiles
object tracks the state of locked files.
2. If a file is already locked, the callback is queued.
3. If the file is not locked, it is locked, and queued callbacks are processed sequentially using the next
function.
4. A fnUnlock
function is provided to release the lock after the operation is complete.
---
## Key Features
- Thread Safety: Ensures that file operations are serialized for the same file.
- Asynchronous Operations: All operations are non-blocking and use callbacks.
- IPC Support: Allows communication with background processes via the net
module.
- Configurable Behavior: Options like enableSyncWrites
provide flexibility for synchronous or asynchronous writes.
---
## Config Sets
- enableSyncWrites: Enable synchronous writing. This is safer than asynchronous writing. (added with version 1.2)
- ipc_port: Port number. See more about net-fn
connection.
- ipc_host: Hostname.See more about net-fn
connection.
json
{
"production": {
"file_lockdown": {
"enableSyncWrites": false,
"ipc_port": 8021,
"ipc_host": "localhost"
}
}
}
## Reference
Below is a list of the available functions and their usage:
### lockFile
Locks a file for exclusive access.
javascript
/**
* @param {string} filePath
* @param {(err:any,callback:(err:any,fnUnlock:()void)void)void} callback function(err,fnUnlock()=>void){...}
*/
function lockFile(filePath, callback)
### lockReadFile
Reads a file while ensuring it is locked during the operation.
javascript
/**
* @param {string} filePath
* @param {(err:any,data:Buffer)void} callback function(err,data)
* @param {string} encoding Default: "utf8"
*/
function lockReadFile(filePath, callback, encoding = "utf8")
### lockWriteFile
Writes data to a file, optionally truncating it first.
javascript
/**
* @param {string} filePath
* @param {Buffer} bufferdata
* @param {(err:any)void} callback function(err)
* @param {string} encoding Default: "utf8"
*/
function lockWriteFile(filePath, buffer, callback, encoding = "utf8")
### lockReadWriteFile
Combines reading and writing operations on a file.
javascript
/**
* @param {string} filePath
* @param {(err:any,buf:Buffer,fnWriteClose:(buf:Buffer,isTruncated:boolean, callback:(err:any)void)void)void} fnRead function(err,data,fnWriteClose(buffer))'buffer'dataforwritingandclose|nullforclose
* @param {string} encoding Default: "utf8"
*/
function lockReadWriteFile(filePath, callback, encoding = "utf8",)
### lockAppendFile
Appends data to a file, creating it if it doesn't exist.
javascript
/**
* @param {string} filePath
* @param {Buffer} buffer
* @param {(err:any)void} callback function(err)
* @param {string} encoding Default: "utf8"
*/
function lockAppendFile(filePath, buffer, callback, encoding = "utf8")
### lockDeleteFile
Deletes a file.
javascript
/**
* @param {string} filePath
* @param {(err:any)void} callback function(err)
*/
function lockDeleteFile(filePath, callback)
### lockRename
Renames a file.
javascript
/**
* @param {string} filePath
* @param {string} newPath
* @param {(err:any)void} callback
*/
function lockRename(filePath, newPath, callback)
### lockCreateDir
Creates a directory recursively.
javascript
/**
* @param {string} dirPath
* @param {(err:any)void} callback
*/
function lockCreateDir(dirPath, callback)
### lockDeleteDir
Deletes a directory recursively.
javascript
/**
* @param {string} dirPath
* @param {(err:any)void} callback
*/
function lockDeleteDir(dirPath, callback)
### lockAccess
Checks if a file or directory exists.
javascript
/**
* @param {string} path
* @param {(err:any)void} callback
* @param {number} timeout
*/
function lockAccess(path, callback, timeout)
## License
This project is licensed under the MIT License.
Copyright © Manuel Lõhmus