so basically, I'm trying to use node.js to scan a google document, then if a ROBLOX id is on there it tracks it. When it tracks it, if it joins one of the groups in the id list, it auto-exiles it.
Any help?
I'm a little stuck on the scanning a google document line by line.
I am not sure about how to do it from a google doc, but if you are willing to move to using text files(.txt) I think I could be of assistance.
Using Nodes FS we can read lines using a Line reader
import * as fs from 'fs'
import { createReadStream } from 'fs'
import { createInterface } from 'readline'
const lineReader = createInterface({
input: createReadStream('data/input.txt')
})
const output: string[] = []
lineReader.on('line', (item: string) => {
output.push(If you wanna output something to an output file put it here)
})
// Down here is the output of what you put in the output.push
lineReader.on('close', () => {
fs.writeFile('data/output.txt', output.join('\n'), err => {
if (err) throw err
console.log('The file has been saved!')
})
})
So the above code is in typescript, but typescript can be compiled down into javascript. If this code doesn't work for you I at least hope it gave some knowledge that helped you find your answer.
Related
I'm trying to update a huge text document by deleting text that is dynamically received from an array. I cannot use readFileSync because the file is way too large so I have to stream it. The problem im encountering is the function deletes everything instead of only deleting what's in the array. Perhaps im not understanding how to properly delete something from a stream. How can this be done?
largeFile_example.txt
test_domain_1
test_domain_2
test_domain_3
test_domain_4
test_domain_5
test_domain_6
test_domain_7
test_domain_8
test_domain_9
test_domain_10
stream.js
const es = require('event-stream');
const fs = require('fs');
//array of domains to delete
var domains = ['test_domain_2','test_domain_6','test_domain_8'];
//loop
domains.forEach(function(domain){
//domain to delete
var dom_to_delete = domain;
//stream
var s = fs
.createReadStream('largeFile_example.txt')
.pipe(es.split())
.pipe(
es
.mapSync(function(line) {
//check if found in text
if(line === dom_to_delete){
//delete
var newValue = dom_to_delete.replace(line, '');
fs.createWriteStream('largeFile_example.txt', newValue, 'utf-8');
}
})
.on('error', function(err) {
console.log('Error while reading file.', err);
})
.on('end', function() {
//...do something
}),
);
})
You can simply use readline interface with the streams and you can read line by line. When you encounter any domain from the array just don't add it.
You can use for-of with async/await
const fs = require('fs');
const readline = require('readline');
async function processLine() {
const fileStream = fs.createReadStream('yourfile');
const rl = readline.createInterface({
input: fileStream,
crlfDelay: Infinity
});
// Note: crlfDelay recognize all instances of CR LF
// ('\r\n') in file as a single line break.
for await (const line of rl) {
// each line will be here as domain
// create a write stream and append it to the file
// line by line using { flag: a }
}
}
processLine();
To delete the domains from the existing file, you need to follow these steps:
Need to read the file as a stream.
Replace the text you don't want with the '' using regex or replace method.
add the updated content to the temp file or a new file.
There is no way you can read from one point and update the same line. I mean I am not aware of such a technique in Node.js(will be happy to know that). So that's why you need to create a new file and once updated remove the old file.
Maybe you can add some more value to how you code it as I am not sure why you want to do that. If your file is not large you can do that in-place, but your case is different.
Having an issue where I will randomly get this error after about an hour of my code running.
SyntaxError: Unexpected end of JSON input
at JSON.parse (<anonymous>)
Here is my code:
function matchMaking() {
setInterval(function() {
fs.readFile('./rankedQueue.json', 'utf8', function(err, data) {
const file = JSON.parse(data); //The line the error occurs
if (err) {
console.log(err)
} else {
//lots of code here
}
})
}, 10 * 1000)
}
edit: This is the content of the JSON file.
{
"queue": [],
"waiting": [],
"lowLevel": [],
"placeHolder": [
{
"test": "test"
}
]
}
The arrays are being pushed to, and then spliced a couple times a minute.
After searching here and some forums, I've tried using fs.readFileSync, which makes the code not run at all. And now I'm finding some specific examples of this error that I can't quite seem to make the solutions apply to me. If anyone has any idea of what I should be changing, It would be appreciated.
Thanks in advance.
As the errors said data is not in json type
Can you make sure the file is valid and it's is what JSON.parse() can parse
How to use fs.readFileSync
Using fs.readFileSync returns a buffer. You can easily convert the buffer into something readable. You use buffer.toString('ascii'). Also, fs.readFile has a callback argument while readFileSync DOESN'T. What I think you were doing about readFileSync was:
fs.readFileSync('./rankedQueue.json', 'utf8', function(err, data) {
const file = JSON.parse(data); //The line the error occurs
if (err) {
console.log(err)
} else {
//lots of code here
}
})
But you should actually be doing this:
var data = fs.readFileSync('./rankedQueue.json');
var JSON = JSON.parse(data.toString('ascii'));
You could drop the 'ascii'.
Incorrect / Hacky Answer
Use require instead. Node.JS has it so it can parse a JSON file for you. Keep in mind that the way you require a file compared to fs is different.
If your code is located at /project/foobar/code.js
JSON is at /project/rankedQueue.json
fs automatically goes to the top of where your project folder is, e.g. /project & So ./rankedQueue.json
require does not do this, and stays in the folder where the file is. You have to add ../ for every folder you want to go above. So: ./../rankedQueue.json.
I'd suggest also running your JSON through a validator as well so it can tell you whats wrong.
I'm using NodeJS on a VM. One part of it serves up pages, and another part is an API. I've run into a problem, where fs.createReadStream attempts to access a different path than what is being passed into the function. I made a small test server to see if it was something else in the server affecting path usage, for whatever reason, but it's happening on my test server as well. First, here's the code:
const fs = require('fs');
const path = require('path');
const csv = require('csv-parser');
const readCSV = (filename) => {
console.log('READ CSV GOT ' + filename); // show me what you got
return new Promise((resolve, reject) => {
const arr = [];
fs.createReadStream(filename)
.pipe(csv())
.on('data', row => {
arr.push(row);
})
.on('error', err => {
console.log(err);
})
.on('end', () => {
resolve(arr);
});
}
}
// tried this:
// const dir = path.relative(
// path.join('path', 'to', 'this', 'file),
// path.join('path', 'to', 'CONTENT.csv')
// );
// tried a literal relative path:
// const dir = '../data/CONTENT.csv';
// tried a literal absolute path:
// const dir = '/repo/directory/server/data/CONTENT.csv';
// tried an absolute path:
const dir = path.join(__dirname, 'data', 'CONTENT.csv');
const content = readCSV(dir)
.then(result => {console.log(result[0]);})
.catch(err => {console.log(err);});
...but any way I slice it, I get the following output:
READCSV GOT /repo/directory/server/data/CONTENT.csv
throw er; // Unhandled 'error' event
^
Error: ENOENT: no such file or directory, open '/repo/directory/data/CONTENT.csv'
i.e., is fs.createReadStream somehow stripping out the directory of the server, for some reason? I suppose I could hard code the directory into the call to createReadStream, maybe? I just want to know why this is happening.
Some extra: I'm stuck on node v8.11, can't go any higher. On the server itself, I believe I'm using older function(param) {...} instead of arrow functions -- but the behavior is exactly the same.
Please help!!
Code is perfect working.
I think you file CONTENT.csv should be in data folder like "/repo/directory/data/CONTENT.csv".
I'm answering my own question, because I found an answer, I'm not entirely sure why it's working, and at least it's interesting. To the best of my estimation, it's got something to do with the call stack, and where NodeJS identifies as the origin of the function call. I've got my server set up in an MVC pattern so my main app.js is in the root dir, and the function that's being called is in /controllers folder, and I've been trying to do relative paths from that folder -- I'm still not sure why absolute paths didn't work.
The call stack goes:
app.js:
app.use('/somepath', endpointRouter);
...then in endpointRouter.js:
router.get('/request/file', endpointController.getFile);
...then finally in endpointController.js:
const readCSV = filename => {
//the code I shared
}
exports.getFile = (req, res, next) => {
// code that calls readCSV(filename)
}
...and I believe that because Node views the chain as originating from app.js, it then treats all relative paths as relative to app.js, in my root folder. Basically when I switched to the super unintuitive single-dot-relative path: './data/CONTENT.csv', it worked with no issue.
This a repeat question (not yet answered) but I have revised and tightened up the code. And, I have included the specific example. I am sorry to keep beating this drum, but I need help.
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 (or fs-extra). 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. I do not "get" why I can get the data manually but I cannot get it programmatically, using the same uri. What am I missing? Help appreciated.
Your File URI is in the wrong format.
It shouldn't contain the File:// protocol (that's a browser-specific thing).
I'd imagine you want C://Users/doug5solas/sandbox/libertyMutual/server/api/ids.json.
I solved the problem by going to readFileSync. I don't like it but it works and it is only one read.
I was trying to use neo4j at backend. First I want to import csv to neo4j. (first tried to see how many lines csv file has)
But having problem, the code is following
var neo4j = require('neo4j-driver').v1;
var driver = neo4j.driver("bolt://localhost", neo4j.auth.basic("neo4j", "neo4j"));
function createGraphDataBase(csvfilepath)
{
var session = driver.session();
return session
.run( 'LOAD CSV FROM {csvfilepath} AS line RETURN count(*)',
{csvfilepath}
)
.then(result => {
session.close();
console.log(' %d lines in csv.file', result);
return result;
})
.catch(error => {
session.close();
console.log(error);
return error;
});
}
the "csvfilepath" is the path of csv file, it is as follows.
'/Users/.../Documents/Project/.../test/spots.csv';
is there something wrong with giving path like this?
I am calling that function on other module as
var api = require('./neo4j.js');
const csvFile = path.join(__dirname,csvFileName);
api.createGraphDataBase(csvFile);
I am having error as
Error: Connection was closed by server
....
I am new to these, please help!
The URL that you specify in a LOAD CSV clause must be a legal URL.
As stated in this guide:
Make sure to use the right URLs esp. file URLs.+ On OSX and Unix use
file:///path/to/data.csv, on Windows, please use
file:c:/path/to/data.csv
In your case, csvfilepath needs to specify the file:/// protocol (since you seem to be running on OSX) for a local file. Based on your example, the value should be something like this:
'file:///Users/.../Documents/Project/.../test/spots.csv'