Node.js throws a "ENOENT" when I trying to write a file with a name too large - node.js

Question

I'm writing a session library for Express.js that stores the sessions in encrypted files. The basic interfaces hierarchy is:
export interface Current<T = any> {
load(): Promise<T>;
save(value: T): Promise<void>;
}
export interface Manager {
current<T = any>(): Current<T>;
create(): Promise<void>;
delete(): Promise<void>;
rewind(): void;
}
declare global {
namespace Express {
export interface Request {
session: Manager;
}
}
}
Every session is stored in a JSON file, which name is a unique hash id. That hash is returned to the client as a cookie. The implementation it's like that:
import { sessionCrossover } from '.';
import express from 'express';
const app = express();
app.use(sessionCrossover({
path: './data',
expires: 1000 * 10,
hashLength: 126
}));
For create a new session:
// The data structure of every session in this example
interface Data {
id: number;
value: string;
}
// Create an endpoint for create a new session
app.get('/create', async (req, res) => {
try {
// Get the current session instance
const current = req.session.current<Data>();
if (!current) {
// Create a new session instance
await req.session.create();
// Save in the current session the data. Just in this
// case, if the session file doesn't exist, it will
// be created. This method throws the error...
await req.session
.current<Data>()
.save({
id: ++id,
value: new Date().toJSON()
});
res.json('Session created sucessfully');
} else {
req.session.rewind();
res.json('Session rewinded...');
}
} catch (err) {
console.error(err);
res.json(err);
}
});
Inside of the method that throws the error:
import { File } from '../tool/fsys';
import { Current } from './interfaces';
export class CurrentSession<T = any> implements Current<T> {
private _file: File;
// The related method
save(value: T): Promise<void> {
if (!this._killed) {
const text = JSON.stringify(value, null, ' ');
const byte = Buffer.from(text, 'utf8');
// Throws the error
return this._file.write(byte);
} else {
return Promise.resolve();
}
}
}
And the File class:
import * as fs from 'fs';
import * as fsPromises from 'fs/promises';
export class File extends FSys {
// The related method
public write(byte: Buffer): Promise<void> {
// this._path it's a protected property of FSys
return fsPromises.writeFile(this._path, byte);
}
}
You can set the current hash length in the middleware shown before. The problem is this:
When you set a hash of a 126 bytes or more, node.js throws an "ENOENT" error (path not found).
When the hash is 125 bytes or less the file with the session it's created normally.
My questions are:
Why node.js thows an "ENOENT" (path not found error) when i try to create a file with a large filename?
Exists a method to detect a "too large filesize" exception in windows?
Observations:
I tried with different hash byte length. The paths in those cases, are:
Hash length = 8; OK
C:\Projects\Node.JS\modules\session-crossover\data\be49c866b0181718.json
Hash length = 64; OK
C:\Projects\Node.JS\modules\session-crossover\data\419410c8db26d74563e31b3c0a12e9fb12d31951abe6b280869af47db088c9acaf251de12cd6b6fc51bf3182fa07597add2b48825498d869b99e914c64d42efa.json
Hash length = 125; OK
C:\Projects\Node.JS\modules\session-crossover\data\b6f4026e893fb053e626ca3318771a70e0802ca10bfc4ea018e18f35b04aa7f9e365a9883a35eea381d9cb9ad2ca11c8961e0096aacd2802e9e0b4cd96920c073800f40a1224d99a093f7fa0b4eca8799bc84c4fa84db2b8b62df211824271c4d908d3d62defa6f1890e613e04af86bcd04379b57ab3728e0366ed42c9.json
Hash length = 126; "ENOENT"
C:\Projects\Node.JS\modules\session-crossover\data\7784ae9a697eb7e5a2ccdf7a9b27c4d182e1e637da4efc47d21a1d48f208f1058bf40f6026dccb79702ea61ea3f4ca307fdeb960a38c89187b0c1b66395934a802ee62769810bd191eb85636d6a86c900299b68fcc1ad6ccfbd83aba863fc181a522cd22d0671148b56d6e4c8051b4366439d6855597caad0eb6a4bba043.json