Okay so basicly i have html from which im collecting input text and updating object with it
index.html
<script type="text/javascript" src="script.js"></script>
<span class="fa fa-link fa-fw"></span>
once triggered it is overriding textInput object
script.js - script file linked to index.html
textInput = {
text: '',
};
const exportFile = () => {
var x = document.getElementById("sampleeditor").innerHTML;
textInput = x;
};
now with my updated textInput object i want to pass it to app.js file which will handle write/reading json file. But not sure how i can trigger write/update function from app.js using script.js, if try export functions/modules rest functions used in script.js turning - "declared but value never read"
app.js - my node app file.
const express = require('express')
const port = 3000;
const path = require('path')
const textInput = require('./public/shit')
const app = express()
app.use(express.static('public'));
app.get('/', function(request, response){
response.sendFile(path.join(__dirname + '/index.html'));
})
//write to json
const fs = require('fs');
let data = JSON.stringify(textInput, null, 2);
fs.writeFile('text.json', data, (err) => {
if (err) throw err;
console.log('Data written to file');
});
console.log(textInput);
//read json
fs.readFile('text.json', (err, data) => {
if (err) throw err;
let textInput = JSON.parse(data);
console.log(textInput);
});
console.log('This is after the read call');
////write to json
app.listen(port)
Related
I have 2 files in Node js .I want to merge these 2, but I am facing problem..
This file calls function from python file
const app = express()
let runPy = new Promise(function(success, nosuccess) {
const { spawn } = require('child_process');
const pyprog = spawn('python', ['./ml.py']);
pyprog.stdout.on('data', function(data) {
success(data);
});
pyprog.stderr.on('data', (data) => {
nosuccess(data);
});
});
app.get('/', (req, res) => {
res.write('welcome\n');
runPy.then(function(testMLFunction) {
console.log(testMLFunction.toString());
res.end(testMLFunction);
});
})
app.listen(4000, () => console.log('Application listening on port 4000!'))
python file ml.py
def testMLFunction():
return "hello from Python"
print(testMLFunction())
Below file works on button click with post method
var fs = require('fs');
var server = http.createServer(function (req, res) {
if (req.method === "GET") {
res.writeHead(200, { "Content-Type": "text/html" });
fs.createReadStream("./form.html", "UTF-8").pipe(res);
} else if (req.method === "POST") {
var result = "";
req.on("data", function (chunk) {
console.log(chunk.toString());
result = chunk;
//body=body.toUpperCase;
});
req.on("end", function(){
res.writeHead(200, { "Content-Type": "text/html" });
res.end(result);
});
}
}).listen(3000);
how can I do that..
There are several things wrong here. I will explain as plain as possible.
You forgot to add in your code var express = require('express')
The promise you made, runPy, must be wrapped in a function, whereas your approach will instantly start the promise upon loading the script itself.
You are resolving/rejecting on first incoming output, you shouldn't do that because you won't be able to know what really happened in the shell. You need to store those output lines, this is the only way of you knowing what the script tells you.
In runPy you must resolve/reject upon pyprogr close event.
You cannot access directly the method of another script, no matter what that kind of file that is a py, sh, bat, js. However, you can access internal functions of it by passing arguments to the shell, and of course, that script must have the logic required to deal with those arguments.
When using spawn/exec you must keep in mind that YOU ARE NOT the user executing the script, the node user is, so different outcomes may occur.
Most importantly, your targeted script must PRINT/ECHO to shell, no returns! The best approach would be to print some json string, and parse it in javascript after the shell is closed, so you can have access to an object instead of a string.
Below you will find a demo for your use case, i changed the python file so it can print something.
ml.py
print('I\'m the output from ml.py')
index.js
const express = require('express');
const app = express()
let runPy = function () { // the promise is now wrapped in a function so it won't trigger on script load
return new Promise(function (success, nosuccess) {
const {spawn} = require('child_process');
const pyprog = spawn('python', ['./ml.py'], {shell: true}); // add shell:true so node will spawn it with your system shell.
let storeLines = []; // store the printed rows from the script
let storeErrors = []; // store errors occurred
pyprog.stdout.on('data', function (data) {
storeLines.push(data);
});
pyprog.stderr.on('data', (data) => {
storeErrors.push(data);
});
pyprog.on('close', () => {
// if we have errors will reject the promise and we'll catch it later
if (storeErrors.length) {
nosuccess(new Error(Buffer.concat(storeErrors).toString()));
} else {
success(storeLines);
}
})
})
};
let path = require('path');
app.use(express.json());
app.use(express.urlencoded({ extended: true })); // you need to set this so you can catch POST requests
app.all('/', (req, res) => { // i've change this from .get to .all so you can catch both get and post requests here
console.log('post params', req.body);
if(req.body.hasOwnProperty('btn-send')){
runPy()
.then(function (pyOutputBuffer) {
let message = 'You sent this params:\n' +JSON.stringify(req.body, null,2) + '\n';
message += Buffer.concat(pyOutputBuffer).toString();
res.end(message);
})
.catch(console.log)
}else{
res.sendFile(path.join(__dirname,'form.html')); // you need an absolute path to 'file.html'
}
});
app.listen(4000, () => console.log('Application listening on port 4000!'));
form.html
<div>hello there</div>
<form action="/" method="post">
<input type="text" value="" name="some-text"/>
<button type="submit" value="1" name="btn-send" >Press me!</button>
</form>
I am trying to write a file to a directory templates then stream a zip with the content that was written. However, the when the zip file is returned it says Failed - Network Error which is due to the fs.writeFile in the controller. If i remove the WriteFile stream then the zipping works fine. My question is how do i first write the file then run the zip. There seems to be something synchronous happening with the archiving and file writing of typeArrayString.
Controller:
exports.download_one_feed = function(req, res, next) {
Feed.findOne({'name': req.params.id})
.exec(function(err, dbfeeds){
if(err){
res.send('get error has occured in routes/feeds.js');
} else {
const feedArray = dbfeeds.feed.data;
// write file
// get from db collection & write file to download
const typeArrayString = JSON.stringify(feedArray);
let type = 'b'; // test only
fs.writeFile(path.join(appDir, 'templates/' + type + '/template.json'), typeArrayString, (err) => {
if (err) throw err;
console.log('Saved!');
})
archiverService.FileArchiver(feedArray, res);
}
})
};
Archive Service
const archiver = require('archiver')
const zip = archiver('zip')
const path = require('path')
const fs = require('fs')
const appDir = path.dirname(require.main.filename)
exports.FileArchiver = function (feedArray, res) {
// const app = this.app;
const uploadsDir = path.join(appDir, '/uploads/');
const templatesDir = path.join(appDir, '/templates/');
const extensions = [".jpg", ".png", ".svg"];
let imageArray = [];
const feedArrayObject = JSON.parse(feedArrayString);
feedArrayObject.forEach(function(x){iterate(x)}); // grab image names from object
imageArray = uniq_fast(imageArray); // remove duplicates
// zip images
for (let i = 0; i < imageArray.length; i++) {
console.log(imageArray[i])
const filePath = path.join(uploadsDir, imageArray[i]);
zip.append(fs.createReadStream(filePath), { name: 'images/'+imageArray[i] });
}
res.attachment('download.zip');
zip.pipe(res);
// zip template directory
console.log(templatesDir)
zip.directory(templatesDir, false);
zip.on('error', (err) => { throw err; });
zip.finalize();
return this;
}
Instead of writing the file then zipping the directory, i used zip.append to override the old file in the directory.
I have a task to implement a pseudo cart page and when I click on checkout i want to send a request to a json file "ordersTest.json" with a following structure:
{ "orders": [] }. So when a post request is sent i have to put the data in that orders array in the json. I am completely new to Nodejs and express. This is my first project on it and i came up with a very simple server.
const express = require('express')
const path = require('path')
const fs = require('fs')
const url = require('url')
const bodyParser = require('body-parser')
const app = express()
const ordersJson = require('./public/ordersTest.json');
app.use(bodyParser.json());
app.use(bodyParser.urlencoded({
extended: true
}));
app.post('/api/orders', (req, res) => {
let body = req.body;
console.log(body);
fs.appendFile('./public/ordersTest.json', JSON.stringify(body), err => {
if (err) console.log(err);
})
})
But this thing only appends it to the end of the file. I need to put it inside this orders array
This is my ajax passing an example object in the body of the post:
$(".btn-checkout").on('click', function() {
let date = new Date();
$.ajax({
method : "POST",
url: "/api/orders",
data : {a: "abc"},//{ order: "order",date: date.toDateString(), order: JSON.stringify(cart)},
success : function(success){
console.log(success,'success');
},
error : function(err) {
console.log(err);
}
});
clearCart();
displayClearedCart();
});
You need to parse the JSON file and then treat it like an object. Once you are done with it, convert it to JSON again and overwrite your file. like this
app.post('/api/orders', (req, res) => {
let body = req.body;
var ordersTest = require('./public/ordersTest.json');
ordersTest.orders.push(body);
fs.writeFile('./public/ordersTest.json', JSON.stringify(ordersTest), function(err) {
if (err) res.sendStatus(500)
res.sendStatus(200);
});
})
Not tested, please fix typo error if any.
GOAL: Allow the user to download a PDF
Background: The below code generates a car.pdf file and stores it into the main project's directory when localhost:3000/ is loaded. This is great because I want to find a Car by id in the database, generate a handlebars template, pass the data from Car into it, and generate a PDF from the compiled HTML
Issue: Instead of saving the PDF to the main project's directory, I want it to download to the user's computer.
How can I do this?
Here is my code. I am using the NPM package: html-pdf
helpers/export-helper.js
const fs = require('fs');
const pdf = require('html-pdf');
const Handlebars = require('handlebars');
const { Car } = require('./../models/car');
var writePDF = (res) => {
Car.findById({_id: '58857e256b639400110897af'})
.then((car) => {
var source = fs.readFileSync(__dirname + '/templates/car.handlebars', 'utf8');
var template = Handlebars.compile(source);
var file = template(car);
pdf.create(file, { format: 'Letter' })
.toFile('./car.pdf', (err, res) => {
if (err) return console.log(err);
console.log(res); // { filename: '/app/businesscard.pdf' }
});
})
.catch((errors) => {
console.log(errors);
});
};
module.exports = { writePDF };
routes/home.js
const express = require('express');
const router = express.Router();
const { writePDF } = require('./../helpers/export-helpers');
router.get('/', (req, res) => {
writePDF();
});
module.exports = router;
You should use res.download for this. Like so
router.get('/', (req, res) => {
res.download('car.pdf');
});
https://expressjs.com/en/api.html#res.download
You have to pipe the created pdf with response to client side.
I want to see content of the file that is posted from the client i am using fs module so with below code contents is coming undefined , Any idea what is missing in below code ?
I have file printed in server side to make sure i am gettign the data.
server.js
var data = new multiparty.Form();
var fs = require('fs');
export function create(req, res) {
data.parse(req, function(err,files) {
var file = files.file;
console.log(file);
fs.readFile(file, 'utf8', function(err, contents) {
console.log('content',contents);
});
});
};
I guess the problem might be the signature of the callback you are supplying to data.parse (you are missing the fields argument).
Check it yourself by looking to the examples on multiparty docs
var data = new multiparty.Form();
var fs = require('fs');
export function create(req, res) {
data.parse(req, function(err, fields, files) {
var file = files.file;
console.log(file);
fs.readFile(file, 'utf8', function(err, contents) {
console.log('content',contents);
});
});
};