Revised code, same problem. Why am I getting a NOENT using the node core module 'fs'?

Question

This a repeat question (unanswered) but I have revised and tightened up the code.

This is a Node API. I need to read and write JSON data. I am using the Node core module 'fs', not the npm package by the same name. I have extracted the particular area of concern onto a standalone module that is shown here:

'use strict';

/*==================================================
    This service GETs the list of ids to the json data files 
    to be processed, from a json file with the id 'ids.json'.
    It returns and exports idsList (an array holding the ids of the json data files)
    It also calls putIdsCleared to clear the 'ids.json' file for the next batch of processing
==================================================*/

//  node modules
const fs          = require('fs');
const config      = require('config');

const scheme      = config.get('json.scheme')
const jsonPath    = config.get('json.path');
const url         = `${scheme}${jsonPath}/`;
const idsID       = 'ids.json';
const uri         = `${url}${idsID}`;
let idsList = [];

const getList = async (uri) => {
    await fs.readFile(uri, 'utf8', (err, data) => {
        if (err) {
            return(console.log( new Error(err.message) ));
        }
        return jsonData = JSON.parse(data);
    })
}

//  The idea is to get the empty array written back to 'ids.json' before returning to 'process.js'
const clearList = async (uri) => {
    let data = JSON.stringify({'ids': []});
    await fs.writeFile(uri, data, (err) => {
        if (err) {
            return (console.log( new Error(err.message) ));
        }
        return;
    })
}

getList(uri);

clearList(uri)

console.log('end of idsList',idsList);

module.exports = idsList;

Here is the console output from the execution of the module:

Error: ENOENT: no such file or directory, open 'File:///Users/doug5solas/sandbox/libertyMutual/server/api/ids.json'
    at ReadFileContext.fs.readFile [as callback] (/Users/doug5solas/sandbox/libertyMutual/server/.playground/ids.js:24:33)
    at FSReqWrap.readFileAfterOpen [as oncomplete] (fs.js:235:13)
Error: ENOENT: no such file or directory, open 'File:///Users/doug5solas/sandbox/libertyMutual/server/api/ids.json'
    at fs.writeFile (/Users/doug5solas/sandbox/libertyMutual/server/.playground/ids.js:36:34)
    at fs.js:1167:7
    at FSReqWrap.oncomplete (fs.js:141:20)

I am being told there is no such file or directory. However I can copy the uri (as shown in the error message)

File:///Users/doug5solas/sandbox/libertyMutual/server/api/ids.json

into the search bar of my browser and this is what is returned to me:

{
    "ids": [
        "5sM5YLnnNMN_1540338527220.json",
        "5sM5YLnnNMN_1540389571029.json",
        "6tN6ZMooONO_1540389269289.json"
    ]
}

This result is the expected result. What the heck is going on?

Answer 1 · 2018-11-20T21:17:17Z

November 20, 2018 9:17pm

I had to look this one up in the NodeJS docs because this subtlety isn't obvious: https://nodejs.org/api/fs.html#fs_url_object_support

If you're using a file:// URI for the path you need to create a URL object from it and pass that. Otherwise a string would just be considered a vanilla filesystem path.

Answer 2 · 2018-11-20T18:20:41Z

November 20, 2018 6:20pm

Hi Doug how are you running this? Are you within TreeHouse workspace or a local server?

If you open this:

File:///Users/doug5solas/sandbox/libertyMutual/server/api/ids.json

In your browser and it's giving you the correct json file then it is the callback function which is the problem

Answer 3 · 2018-11-20T19:06:36Z

November 20, 2018 7:06pm

Liam I am running this on my localhost. I used:

File:///Users/doug5solas/sandbox/libertyMutual/server/api/ids.json

because when I tried it with:

localhost:3000//Users/doug5solas/sandbox/libertyMutual/server/api/ids.json

not only did it NOT work programmatically, it didn't work manually. The 'File:///...' was a desperation move. My mind tells me that "localhost:3000..." is the proper way to do it.

In what way is the callback the problem? My understanding is, this is the callback:

(err, data) => {
        if (err) {
            return(console.log( new Error(err.message) ));
        }
        return jsonData = JSON.parse(data);
    })

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Doug Hawkinson

Doug Hawkinson

Revised code, same problem. Why am I getting a NOENT using the node core module 'fs'?

3 Answers

Seth Kroger

Seth Kroger

Doug Hawkinson

Doug Hawkinson

Liam Clarke

Liam Clarke

Doug Hawkinson

Doug Hawkinson