Paths specified with a `.` are relative to the current working directory, not relative to the script file. So the file might be found if you run `node app.js` but not if you run `node folder/app.js`.  The only exception to this is `require(&#39;./file&#39;)` and that is only possible because `require` exists per-module and thus knows what module it is being called from.

To make a path relative to the script, you must use the `__dirname` variable.

    var path = require(&#39;path&#39;);

    path.join(__dirname, &#39;path/to/file&#39;)

or potentially

    path.join(__dirname, &#39;path&#39;, &#39;to&#39;, &#39;file&#39;)

   Here the code to use your app.js

input specifies file name

    res.download(__dirname+&#39;/&#39;+input);



Say you have a form that has values loaded from database.  How do you initialize ng-model?

Example:

    &lt;input name=&quot;card[description]&quot; ng-model=&quot;card.description&quot; value=&quot;Visa-4242&quot;&gt;

In my controller, $scope.card is undefined initially.  Is there a way besides doing something like this?

    $scope.card = {
      description: $(&#39;myinput&#39;).val()
    }

Angular js init ng-model from default values

How do I enable Entity Framework 5 (version 5.0.0) migrations for multiple DB contexts in the same project, where each context corresponds to its own database? When I run `Enable-Migrations` in the PM console (Visual Studio 2012), there&#39;s an error because of there being multiple contexts:

    PM&gt; Enable-Migrations
    More than one context type was found in the assembly &#39;DatabaseService&#39;.
    To enable migrations for DatabaseService.Models.Product1DbContext, use Enable-Migrations -ContextTypeName DatabaseService.Models.Product1DbContext.
    To enable migrations for DatabaseService.Models.Product2DbContext, use Enable-Migrations -ContextTypeName DatabaseService.Models.Product2DbContext.

If I run `Enable-Migrations -ContextTypeName DatabaseService.Models.Product1DbContext` I&#39;m not allowed to run `Enable-Migrations -ContextTypeName DatabaseService.Models.Product2DbContext` because a migration already exists: `Migrations have already been enabled in project &#39;DatabaseService&#39;. To overwrite the existing migrations configuration, use the -Force parameter.`

How do I enable EF migrations for multiple contexts to separate databases?

I have developed a node.js program using the express framework on my computer, where it runs fine with no complaints.

However, when I run the program on my SUSE Studio appliance, where it is intended to live, I receive an error at any file interaction.

    Error: ENOENT, stat &#39;./path/to/file&#39;

I have checked that the file permissions are correct, which they are.  My computer and my appliance are running different versions of node, if this matters.

Any thoughts?  

Node.js, can&#39;t open files. Error: ENOENT, stat &#39;./path/to/file&#39;

I have developed a node.js program using the express framework on my computer, where it runs fine with no complaints.
However, when I run the program on my SUSE Studio appliance, where it is intended to live, I receive an error at any file interaction.
<pre><code class="hljs language-bash">Error: ENOENT, stat './path/to/file'
</code></pre>
I have checked that the file permissions are correct, which they are. My computer and my appliance are running different versions of node, if this matters.
Any thoughts?

I&#39;ve been tinkering with Node.js and found a little problem.  I&#39;ve got a script which resides in a directory called `data`.  I want the script to write some data to a file in a subdirectory within the `data` subdirectory.  However I am getting the following error:

    { [Error: ENOENT, open &#39;D:\data\tmp\test.txt&#39;] errno: 34, code: &#39;ENOENT&#39;, path: &#39;D:\\data\\tmp\\test.txt&#39; }

The code is as follows:

    var fs = require(&#39;fs&#39;);
    fs.writeFile(&quot;tmp/test.txt&quot;, &quot;Hey there!&quot;, function(err) {
        if(err) {
            console.log(err);
        } else {
            console.log(&quot;The file was saved!&quot;);
        }
    }); 

Can anybody help me in finding out how to make Node.js create the directory structure if it does not exits for writing to a file?

Create Directory When Writing To File In Node.js

I am building a multiple page admin interface for an internal enterprise software platform. Think lots of glue logic tying together various APIs, db queries, and shell scripts.

We will be using node.js, the express framework (including jade templates), and LDAP for authentication.

I am struggling to find information regarding design patterns and best practices for authorization in node applications. Preferably, I would like to use the role-based model since my users are familiar with that approach and its care and feeding.

I am new to node.js so please don&#39;t assume I&#39;ve already seen a module or popular blog post. It&#39;s probable that there&#39;s a wealth of information and I simply do not know where to look.

Thanks in advance for any information you are able to provide!

Authorization approaches and design patterns for Node.js applications

I have a mongo document like this.

	{
	    &quot;_id&quot; : ObjectId(&quot;50b429ba0e27b508d854483e&quot;),
	    &quot;array&quot; : [
	        {
	            &quot;id&quot; : &quot;1&quot;,
	            &quot;letter&quot; : &quot;a&quot;
	        },
	        {
	            &quot;id&quot; : &quot;2&quot;,
	            &quot;letter&quot; : &quot;b&quot;
	        }
	    ],
	    &quot;tester&quot; : &quot;tom&quot;
	}
	
I want to be able to insert and update the `array` with a single mongo command and not use a conditional within a `find()` then run `insert()` and `update()` depending on the presence of the object.

The `id` is the item I want to be the selector. So if I update the array with this:

	{
	    &quot;id&quot; : &quot;2&quot;,
	    &quot;letter&quot; : &quot;c&quot;
	}

I have to use a `$set` statement

	db.soup.update({
		&quot;tester&quot;:&quot;tom&quot;,
	    &#39;array.id&#39;: &#39;2&#39;
	}, {
	    $set: {
	        &#39;array.$.letter&#39;: &#39;c&#39;
	    }
	})
	
And if I want to insert a new object into the array

	{
	    &quot;id&quot; : &quot;3&quot;,
	    &quot;letter&quot; : &quot;d&quot;
	}
	
I have to use a `$push` statement

	db.soup.update({
		&quot;tester&quot;:&quot;tom&quot;
	}, {
	    $push: {
	        &#39;array&#39;: {
	            &quot;id&quot;: &quot;3&quot;,
	            &quot;letter&quot;: &quot;d&quot;
	        }
	    }
	})
	
I need a sort of upsert for an array item. 

Do I have to do this programmatically or can I do this with a single mongo call?

Can mongo upsert array data?

I saw a reference to creating a &quot;REPL&quot;.  What is a REPL?

    var arDrone = require(&#39;ar-drone&#39;);
    var client  = arDrone.createClient();
    client.createRepl();


What is a &quot;REPL&quot; in javascript?

Well... I&#39;m back to square one. I can&#39;t figure this out for the life of me.

I&#39;m getting the following error:

    FATAL ERROR: JS Allocation failed - process out of memory

I could enumerate the dozens (yes, dozens) of things I&#39;ve tried to get to the root of this problem, but really it would be far too much. So here are the key points:

 - I can only get it to happen on my production server, and my app is large and complicated, so it is proving very difficult to isolate
 - It happens even though heap size &amp; RSS size are both &lt; 200 Mb, which should not be a problem given that the machines (Amazon Cloud, CentOS, m1.large) have 8Gb RAM

**My assumption is that** (because of the 2nd point), a leak is probably not the cause; rather, it seems like there&#39;s probably a SINGLE object that is very large. The following thread backs up this theory:: https://stackoverflow.com/questions/11189940/in-node-js-using-json-stringify-results-in-process-out-of-memory-error 

What I really need is some way to find out what the state of the memory is at the moment the application crashes, or perhaps a stack trace leading up to the FATAL ERROR.

Based upon my assumption above, a 10-minute-old heap dump is insufficient (since the object would have not resided in memory).

Node.js &quot;FATAL ERROR: JS Allocation failed - process out of memory&quot; -- possible to get a stack trace?

I am having trouble getting my system to log out with PassportJS. It seems the logout route is being called, but its not removing the session. I want it to return 401, if the user is not logged in in specific route. I call authenticateUser to check if user is logged in.

Thanks a lot!   
 
    /******* This in index.js *********/
    // setup passport for username &amp; passport authentication
    adminToolsSetup.setup(passport);

    // admin tool login/logout logic
    app.post(&quot;/adminTool/login&quot;,
        passport.authenticate(&#39;local&#39;, {
            successRedirect: &#39;/adminTool/index.html&#39;,
            failureRedirect: &#39;/&#39;,
            failureFlash: false })
    );
    app.get(&#39;/adminTool/logout&#39;, adminToolsSetup.authenticateUser, function(req, res){
        console.log(&quot;logging out&quot;);
        console.log(res.user);
        req.logout();
        res.redirect(&#39;/&#39;);
    });


    // ******* This is in adminToolSetup ********
    // Setting up user authentication to be using user name and passport as authentication method,
    // this function will fetch the user information from the user name, and compare the password     for authentication
    exports.setup = function(passport) {
        setupLocalStrategy(passport);
        setupSerialization(passport);
    }
    
    function setupLocalStrategy(passport) {
        passport.use(new LocalStrategy(
            function(username, password, done) {
                console.log(&#39;validating user login&#39;);
                dao.retrieveAdminbyName(username, function(err, user) {
                    if (err) { return done(err); }
                    if (!user) {
                        return done(null, false, { message: &#39;Incorrect username.&#39; });
                    }
                    // has password then compare password
                    var hashedPassword = crypto.createHash(&#39;md5&#39;).update(password).digest(&quot;hex&quot;);
                    if (user.adminPassword != hashedPassword) {
                        console.log(&#39;incorrect password&#39;);
                        return done(null, false, { message: &#39;Incorrect password.&#39; });
                    }
                    console.log(&#39;user validated&#39;);
                    return done(null, user);
                });
            }
        ));
    }
    
    function setupSerialization(passport) {
        // serialization
        passport.serializeUser(function(user, done) {
            console.log(&quot;serialize user&quot;);
            done(null, user.adminId);
        });
    
        // de-serialization
        passport.deserializeUser(function(id, done) {
            dao.retrieveUserById(id, function(err, user) {
                console.log(&quot;de-serialize user&quot;);
                done(err, user);
            });
        });
    }
    
    // authenticating the user as needed
    exports.authenticateUser = function(req, res, next) {
        console.log(req.user);
        if (!req.user) {
            return res.send(&quot;401 unauthorized&quot;, 401);
        }
        next();
    }

Why is PassportJS in Node not removing session on logout

In my index.ejs I have this code:

    var current_user = &lt;%= user %&gt;

In my node I have


    app.get(&quot;/&quot;, function(req, res){
        res.locals.user = req.user
        res.render(&quot;index&quot;)
    })

However, on the page I obtain


    var current_user = [object Object]

and if I write 

    var current_user = &lt;%= JSON.stringify(user) %&gt;

I obtain:

    var current_user = {&amp;quot;__v&amp;quot;:0,&amp;quot;_id&amp;quot;:&amp;quot;50bc01938f164ee80b000001&amp;quot;,&amp;quot;agents&amp;quot;:...


Is there a way to pass a JSON that will be **JS readable**?

Express and ejs &lt;%= to render a JSON

I am doing MongoDB lookups by converting a string to BSON. Is there a way for me to determine if the string I have is a valid ObjectID for Mongo before doing the conversion?

Here is the coffeescript for my current findByID function. It works great, but I&#39;d like to lookup by a different attribute if I determine the string is not an ID.

    db.collection &quot;pages&quot;, (err, collection) -&gt;
      collection.findOne
        _id: new BSON.ObjectID(id)
      , (err, item) -&gt;
        if item
          res.send item
        else
          res.send 404

Can I determine if a string is a MongoDB ObjectID?

Suppose the mongodb document(table) &#39;users&#39; is

    {
        _id: 1,
        name: {
            first: &#39;John&#39;,
            last: &#39;Backus&#39;
        },
        birth: new Date(&#39;Dec 03, 1924&#39;),
        death: new Date(&#39;Mar 17, 2007&#39;),
        contribs: [&#39;Fortran&#39;, &#39;ALGOL&#39;, &#39;Backus-Naur Form&#39;, &#39;FP&#39;],
        awards: [
            {
                award: &#39;National Medal&#39;,
                year: 1975,
                by: &#39;NSF&#39;
            },
            {
                award: &#39;Turing Award&#39;,
                year: 1977,
                by: &#39;ACM&#39;
            }
        ]
    }
    // ...and other object(person)s

I want to find the person who has the award &#39;National Medal&#39; and must be awarded in year 1975
There could be other persons who have this award in different years.

How can I find this person using award type and year. So I can get exact person.

Content Type	Original Author	Original Content on Stackoverflow
Question	user712410	View Question on Stackoverflow
Solution 1 - node.js	loganfsmyth	View Answer on Stackoverflow
Solution 2 - node.js	AmirtharajCVijay	View Answer on Stackoverflow

Node.js, can't open files. Error: ENOENT, stat './path/to/file'

node.js Problem Overview

node.js Solutions

Solution 1 - node.js

Solution 2 - node.js

How do I enable EF migrations for multiple contexts to separate databases?

Angular js init ng-model from default values

Attributions