I would like my server.js to basically save a string to a .txt file for a history/log on the server.
Since you can not use php or jQuery in server.js, I don't know how to do this, nor has anyone asked the same question.
Do you know how?
Thank you.
First you get the file system library:
var fs = require('fs');
Then, you can just output like this:
fs.writeFile("log.txt", stringText, function(error) {
if(error) throw error; // Handle the error just in case
else console.log("Success!");
});
you can use the fs module.
something like that will do the job :
let myString = "very very important string";
let fs = require("fs");
// you can use async if you prefer, check the doc
fs.writeFileSync("./myFile.txt", myString);
Related
There are a lot of solutions that are based on the fetch api or the XMLHttpRequest, but they return CORS or same-origin-policy errors.
The File/Filereader API works out of the box , but only for files chosen by the user via a input file (because that is the only way to import them as a File obj)
Is there a way to do something simple and minimal like
const myfile = new File('relative/path/to/file') //just use a path
const fr = new FileReader();
fr.readAsText(myfile);
Thanks
Try the following JS, this will use fs to read the file and if it exists it will turn it into a string and output to console. You can change it up to however you'd like.
var fs = require('fs');
fs.readFile('test.txt', 'utf8', function(err, data) {
if (err) {
return console.log(err);
}
console.log(data);
});
I need to get number of items of specific directory in Node.js
If I get the items like
var dirItems = fs.readdirSync(__dirname+'/my_dir');
and then get specific item like
dirItems[1]
everything is ok
But if I try to get their number like
dirItems.length
or
Object.keys(dirItems).length
the page doesn't work in the browser
How to get the number of directory items?
UPDATED
My full code:
var http = require('http'),
fs = require('fs');
http.createServer(function(req, res) {
var dirItems = fs.readdirSync(__dirname+'/my_dir');
res.writeHead(200, {'Content-Type': 'text/html'});
res.end(dirItems.length);
}).listen(80, 'localhost');
I was able to reproduce the error nyou get.
res.end() for the basic http server class is very picky about what you send it. You must give it a string (the error you got should have been a big clue here).
So, change this:
res.end(dirItems.length);
to this:
res.end(dirItems.length.toString());
And, it works for me. I was able to reproduce your original error and then make it work by making this simple change.
Logically, you can only send string data as an http response so apparently res.end() isn't smart enough to attempt a string conversion on its own. You have to do it yourself.
FYI, if you use a higher level framework like Express, it is more tolerant of what you send it (it will attempt a string conversion in a situation like this).
Here is how I would do it:
const fs = require('fs');
const dir = './somedir';
fs.readdir(dir, (err, files) => {
console.log(files.length);
});
i'm pretty new into NodeJs. And i am trying to read a file into a variable.
Here is my code.
var fs = require("fs"),
path = require("path"),
util = require("util");
var content;
console.log(content);
fs.readFile(path.join(__dirname,"helpers","test.txt"), 'utf8',function (err,data) {
if (err) {
console.log(err);
process.exit(1);
}
content = util.format(data,"test","test","test");
});
console.log(content);
But every time i run the script i get
undefined and undefined
What am i missing? Help please!
As stated in the comments under your question, node is asynchronous - meaning that your function has not completed execution when your second console.log function is called.
If you move the log statement inside the the callback after reading the file, you should see the contents outputted:
var fs = require("fs"),
path = require("path"),
util = require("util");
var content;
console.log(content);
fs.readFile(path.join(__dirname, "helpers", "test.txt"), 'utf8', function (err, data) {
if (err) {
console.log(err);
process.exit(1);
}
content = util.format(data, "test", "test", "test");
console.log(content);
});
Even though this will solve your immediately problem, without an understanding of the async nature of node, you're going to encounter a lot of issues.
This similar stackoverflow answer goes into more details of what other alternatives are available.
The following code snippet uses ReadStream. It reads your data in separated chunks, if your data file is small it will read the data in a single chunk. However this is a asynchronous task. So if you want to perform any task with your data, you need to include them within the ReadStream portion.
var fs = require('fs');
var readStream = fs.createReadStream(__dirname + '/readMe.txt', 'utf8');
/* include the file directory and file name instead of <__dirname + '/readMe.txt'> */
var content;
readStream.on('data', function(chunk){
content = chunk;
performTask();
});
function performTask(){
console.log(content);
}
There is also another easy way by using synchronous task. As this is a synchronous task, you do not need to worry about its executions. The program will only move to the next line after execution of the current line unlike the asynchronous task.
A more clear and detailed answer is provided in the following link:
Get data from fs.readFile
var fs = require('fs');
var content = fs.readFileSync('readMe.txt','utf8');
/* include your file name instead of <'readMe.txt'> and make sure the file is in the same directory. */
or easily as follows:
const fs = require('fs');
const doAsync = require('doasync');
doAsync(fs).readFile('./file.txt')
.then((data) => console.log(data));
I've distilled my issue to some really basic functionality here. Basically, we're sending a request to a server (you can go ahead and c/p the URL and see the json document we get in response).
We get the response, we pipe it into a write stream and save it as a .json file - but the problem is that the file keeps being cut off. Is the .json file too large? Or am I missing something? Node.js newbie - massively appreciate any help I can get.
var fs = require('fs');
var url = 'https://crest-tq.eveonline.com/market/10000002/history/?type=https://crest-tq.eveonline.com/inventory/types/34/'
var request = require('request');
request(url).pipe(fs.createWriteStream('34_sell.json'));
var fs = require('fs');
var request = require('request');
var url = 'https://crest-tq.eveonline.com/market/10000002/history/?type=https://crest-tq.eveonline.com/inventory/types/34/';
request(url).pipe(fs.createWriteStream('34_sell.json'));
Not an answer but this is the code I used. I'm using request version 2.74.0. And node version v5.4.1.
Try writing a get request to the url and send the json as response and write an error handling statement like if err then throw err..console log and see the result..hope it works
When user register, i save its name in mysql (russian name in database seems like - ÐрминÑÐ). When I take data from database with PHP and print out, it works good (show russian letters), but when user connect to node.js server (using socket.io), make mysql query (using node-mysql module) and receive data from query, then his name seems like - ÐрминÑÐ.
How to get readable letters?
Here are some lines from my server file:
var mysql = require('mysql');
var db = mysql.createConnection({host:'x', user:'x', password:'x', database:'x', charset:'UTF8_GENERAL_CI'});
db.connect();
var http = require('http');
var server = http.createServer(function(req,res){
req.setEncoding("utf8");
}).listen(8080);
var io = require('socket.io').listen(server);
I think this should help:
function onRequest(request, response) {
...
request.setEncoding("utf8");
...
}
http.createServer(onRequest).listen(8888);
Here is what I'm using in the front-end:
function encode_utf8(s) {
return unescape(encodeURIComponent(s));
}
function decode_utf8(s) {
return decodeURIComponent(escape(s));
}
So, try passing your string to
decodeURIComponent(escape(name));
I had the same problem.
Try to debug it. If console.log data from fronted have incorrect charset, just update your socket.io script.