fs.WriteFile launches callback before actually writing the file - javascript

I have the following express request callback
zip.addLocalFolder(`/path/to/folder`, `./`);
var data = zip.toBuffer();
fs.writeFile(`path/to/download.zip`,data,function (err) {
if (err) return console.log(err);
res.download(`path/to/download.zip`)
});
The fs.writeFile seems to be writing the file after calling the callback function.
Edit: the file is being written successfully. It is the fact that it is being written after I do res.download() that causes the error
If I call res.download() in a setTimeout, of 1 second, the execution ends successfully.
I get this error:
ENOENT: no such file or directory, stat 'path/to/download.zip`
Changing the code to
zip.addLocalFolder(`/path/to/folder`, `./`);
var data = zip.toBuffer();
fs.writeFileSync(`path/to/download.zip`,data);
res.download(`path/to/download.zip`);
has the same effect.
The library I use, adm-zip, has a method for writing the zip file, and working with that has the very same effect.
Is there something I'm missing ?

The issue here is that native file writing methods in nodejs will fail if the selected folder does not exist.
So before writing to path/to/folder/download.zip you need to make sure that all these folders path/to/folder already exist.
There are few methods of how achieve that. For example the fs.mkdir method available from Node v10.12
fs.mkdir('/path/to/folder', { recursive: true }, (err) => {
if (err) throw err;
... your write file code here
});
In the example above, node will firstly create all the folders in the path (see the recursive:true option) and then you can write file there.
Important note:
If you are sure, that all directories exist, then the issue is the wrong path passed to the method. Consider using the global __dirname variable in order to resolve correct path to the directory of your script file. Also you may use ./ prefix in path if the path should be relative to the place where app was executed.

Related

Getting test results when creating a Karma server programmatically

I am trying to run multiple Karma test files in parallel from inside a Node script and get to know which tests are passing or failing. Right now what I have is this:
const exec = require("child_process").exec;
exec("karma start " + filename, (error, stdout, stderr) => {
// handle errors and test results...
});
The code above works well, and I can get the information on tests passed or failed from stdout. However, it requires having installed Karma and all of the associated dependencies (reporters, browser launchers, etc.) globally. I am looking for a solution that doesn't require me to install all dependencies globally.
My first thought was this:
const karma = require("karma");
const server = new karma.Server(config, () => {
// some logic
});
However, when trying this other approach, I have been unable to gather the test results programmatically.
When using new karma.Server(), is there any way in which I could know which tests have passed or failed (and, ideally, a stack trace of the error)? Alternatively, is there any other way in which I can execute my tests and get the desired information programmatically without the need to install dependencies globally?
Actually, changing the exec line to this seems to do the trick:
exec("node node_modules/karma/bin/karma start " + filename, (error, stdout, stderr) => {
It turns out I'd only need to run the locally installed version of Karma instead of the global one. :-)

Copy files with Yeoman generator doesn't work

I'm developing my own generator with Yeoman. When I try to copy some files, nothing happens. No error, the process continues until it reach the end, but no files are copied. The generator has a /templates dir with a bunch of html files, each file has a few html lines, at the moment quite simple stuff.
This is my copy method:
copyMainFiles: function(){
console.log('copyMainFiles dir:' + process.cwd() + '+++++');
console.log('file exists? '+fs.existsSync('_footer.html') );
this.copy("_footer.html", "app/footer.html");
console.log('footer copied');
this.copy("_gruntfile.js", "Gruntfile.js");
console.log('gruntfile copied');
this.copy("_package.json", "package.json");
console.log('package copied');
this.copy("_main.css", "app/css/main.css");
console.log('main.css copied');
var context = {
site_name: this.appName
};
console.log('all files copied');
//template method makes the replacement and then copy
this.template("_header.html", "app/header.html", context);
console.log('header template processed');
},
this is the console output:
$ yo trx
method 1 just ran
method 2 just ran
? What is your app's name ?
Kosheen
? Would you like to generate a demo section ? Yes
all dirs created
copyMainFiles dir:C:\cygwin\Applications\MAMP\htdocs\prueba-trx+++++
file exists? false
footer copied
gruntfile copied
package copied
main.css copied
all files copied
header template processed
running npm
and that's it. Never returns to system prompt.
Besides the fact that fs.existsSync returns false (the file exists: htdocs\generator-trx\generators\app\templates_footer.html ), if I try to copy a non-existent file I get the typical error.
Folders are created previously with no issue. There's a .yo_rc.json file with {} in the root of the destination folder. The Yeoman version is 1.4.8, working on Windows 7.
Is copy() the proper way to do this or is no longer valid? How can I copy a simple file in this scenario?
Beside the fact of I was using deprecated methods, the proper way to achive this task is as follow:
this.fs.copy(
this.templatePath('_bower.json'),
this.destinationPath('bower.json')
);
Not sure what your issue is, but you should read the Yeoman official documentation on how to handle files: http://yeoman.io/authoring/file-system.html
You're using old and deprecated methods.

Loading hooks in CucumberJS with Protractor and Gulp

I setup CucumberJS with Protractor and Gulp. I followed the documentation available here:
https://github.com/cucumber/cucumber-js
I have my feature file and step definition file. I also created world.js file in support folder and it is loaded in my step definition file with:
this.World = require("../support/world.js").World;
So the same way as it is presented in the documentation.
Everything works till this moment.
I tried to add some cucumber hooks to my case. I created hooks.js file in the support folder as it is proposed in the documentation, so:
// features/support/hooks.js (this path is just a suggestion)
var myHooks = function () {
this.Before(function (callback) {
// Just like inside step definitions, "this" is set to a World instance.
// It's actually the same instance the current scenario step definitions
// will receive.
// Let's say we have a bunch of "maintenance" methods available on our World
// instance, we can fire some to prepare the application for the next
// scenario:
console.log("Before hook");
// Don't forget to tell Cucumber when you're done:
callback();
});
};
module.exports = myHooks;
The documentation does not say how this hook.js file should be loaded in my step definitions so I assume that it is somehow loaded with the "convention over configuration" approach. Unfortunately, the file is not loaded and the Before method is not executed.
Any ideas?
If hooks are NOT in the same folder as your step_definitions, you would need to explicitly specify where your hooks are using --require. For example,
cucumber.js test/functional/features/xyz.feature
--require test/functional/step_definitions/
--require features/support/ --format=pretty
To avoid this, I usually keep my hooks under step_definitions folder. Since you need to specify require for step_definitions anyways, you don't need to explicitly specify require for hooks. So lets say if your hooks are in test/functional/step_definitions/, with following your hooks should get invoked.
cucumber.js test/functional/features/xyz.feature
--require test/functional/step_definitions/
--format=pretty
Once you have your hooks.js file, go to your cucumberOpts inside of your protractor.conf.js file and add the path to your hooks.js file there, that's it, your hooks.js file will be loaded.
cucumberOpts: {
require: [
conf.paths.e2e + '/steps/**/*Steps.js',
conf.paths.e2e + '/utilities/hooks.js',
],
tags: ['~#wip', '~#manual'],
format: 'pretty'
}
You can also include console.log('Was my hook loaded') in your hooks.js file and search for that log text later to ensure your hook was properly loaded.

Node JS Error when copying file across partition. How to resolve this issue? [duplicate]

I'm trying to move a file from one partition to another in a Node.js script. When I used fs.renameSync I received Error: EXDEV, Cross-device link. I'd copy it over and delete the original, but I don't see a command to copy files either. How can this be done?
You need to copy and unlink when moving files across different partitions. Try this,
var fs = require('fs');
//var util = require('util');
var is = fs.createReadStream('source_file');
var os = fs.createWriteStream('destination_file');
is.pipe(os);
is.on('end',function() {
fs.unlinkSync('source_file');
});
/* node.js 0.6 and earlier you can use util.pump:
util.pump(is, os, function() {
fs.unlinkSync('source_file');
});
*/
I know this is already answered, but I ran across a similar problem and ended up with something along the lines of:
require('child_process').spawn('cp', ['-r', source, destination])
What this does is call the command cp ("copy"). Since we're stepping outside of Node.js, this command needs to be supported by your system.
I know it's not the most elegant, but it did what I needed :)
One more solution to the problem.
There's a package called fs.extra written by "coolaj86" on npm.
You use it like so:
npm install fs.extra
fs = require ('fs.extra');
fs.move ('foo.txt', 'bar.txt', function (err) {
if (err) { throw err; }
console.log ("Moved 'foo.txt' to 'bar.txt'");
});
I've read the source code for this thing. It attempts to do a standard fs.rename() then, if it fails, it does a copy and deletes the original using the same util.pump() that #chandru uses.
to import the module and save it to your package.json file
npm install mv --save
then use it like so:
var mv = require('mv');
mv('source_file', 'destination_file', function (err) {
if (err) {
throw err;
}
console.log('file moved successfully');
});
I made a Node.js module that just handles it for you. You don't have to think about whether it's going to be moved within the same partition or not. It's the fastest solution available, as it uses the recent fs.copyFile() Node.js API to copy the file when moving to a different partition/disk.
Just install move-file:
$ npm install move-file
Then use it like this:
const moveFile = require('move-file');
(async () => {
await moveFile(fromPath, toPath);
console.log('File moved');
})();

How do I move file a to a different partition or device in Node.js?

I'm trying to move a file from one partition to another in a Node.js script. When I used fs.renameSync I received Error: EXDEV, Cross-device link. I'd copy it over and delete the original, but I don't see a command to copy files either. How can this be done?
You need to copy and unlink when moving files across different partitions. Try this,
var fs = require('fs');
//var util = require('util');
var is = fs.createReadStream('source_file');
var os = fs.createWriteStream('destination_file');
is.pipe(os);
is.on('end',function() {
fs.unlinkSync('source_file');
});
/* node.js 0.6 and earlier you can use util.pump:
util.pump(is, os, function() {
fs.unlinkSync('source_file');
});
*/
I know this is already answered, but I ran across a similar problem and ended up with something along the lines of:
require('child_process').spawn('cp', ['-r', source, destination])
What this does is call the command cp ("copy"). Since we're stepping outside of Node.js, this command needs to be supported by your system.
I know it's not the most elegant, but it did what I needed :)
One more solution to the problem.
There's a package called fs.extra written by "coolaj86" on npm.
You use it like so:
npm install fs.extra
fs = require ('fs.extra');
fs.move ('foo.txt', 'bar.txt', function (err) {
if (err) { throw err; }
console.log ("Moved 'foo.txt' to 'bar.txt'");
});
I've read the source code for this thing. It attempts to do a standard fs.rename() then, if it fails, it does a copy and deletes the original using the same util.pump() that #chandru uses.
to import the module and save it to your package.json file
npm install mv --save
then use it like so:
var mv = require('mv');
mv('source_file', 'destination_file', function (err) {
if (err) {
throw err;
}
console.log('file moved successfully');
});
I made a Node.js module that just handles it for you. You don't have to think about whether it's going to be moved within the same partition or not. It's the fastest solution available, as it uses the recent fs.copyFile() Node.js API to copy the file when moving to a different partition/disk.
Just install move-file:
$ npm install move-file
Then use it like this:
const moveFile = require('move-file');
(async () => {
await moveFile(fromPath, toPath);
console.log('File moved');
})();

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