I looking at using Javascript server side and took a look at persevere/pintura but for a novice like me, I need more documentation and tutorials and CouchDB seems to have a lot of that but is it used as a server side js tool?
Kind Regards
Yes (seconding what #Pointy said above). The JavaScript in CouchDB does run server-side. :)
Beyond that, though, JavaScript in CouchDB can do far more than just map/reduce queries. It's also used for document validation, update handling (for processing XML POSTed to CouchDB for example), as well as HTML or other markup output from either a single JSON document (using _show) or from the results of a map/reduce query (using _list).
CouchDB does not, however, offer filesystem access or TCP/IP listeners as Node.js does. Right now, the JavaScript is focused on the "shipping and handling" for the database contents (things like validation, formatting, and querying).
If you're interested in looking into options for handling things that CouchDB doesn't do "internally" (image processing, sending e-mails, etc), you might checkout my reply about CouchApp architecture options.
CouchApp's are definitely a viable option for web apps. Coupling those with replication, it's hard to beat.
http://nodejs.org/ is a great example for server-side javascript. If you don't want to write your complete webapp on NodeJS you can trigger it via the node command.
CouchDB is a database with an interresting feature, it allows you to interact via a RestFull api making it ideally suited to access over the web, either in javascript or other client environments. If you are looking for a server-side javascript development environment, try Servoy. It allows full featured server-side application development in javascript including easy database access to all major databases.
Short Answer: Yes.
Longer Answer:
There is a Javascript Engine shipped with CouchDB, which is SpiderMonkey
(the very first engine, open source, written by Brendan Eich, creator of javascript)
CouchDB's View function is JavaScript function running server side that acts as the Map half of a map/reduce operation to construct view.
Then there is client side javascript API, which can be used to communicate with the REST layer to fetch/update documents, which is also where jQuery is used by CouchDB.
More on CouchDB's both server-side & client side javascript capability:
The default engine is capable of doing many features, while package availability is limited compared to Node.js. Kan.so can be considered "NPM for CouchDB, where some packages are server side.
For example, there are frameworks like duality that try to make use of both server side & client side javascript capability to reuse code for rendering with couchDB.
More on the engine:
(The selection of spider Monkey over v8 is because for couchDB's use case the map reduce is not v8 designed for. Also include packaging, multi-threading and also historical reason v8 did not exist that time when spiderMoney is chosen) see [the mailing list] and tweet2
There is even project to port the whole CouchDB to Node.js (i.e. instead of Erlang), Chesterfield
I am glad if someone can add how Erlang talk with the javscript engine.
Thanks for everyone's answer, this is an important thing to make clear for people like me messing up couchDB with some Node.js packages
No, CouchDB is a document-oriented database that can be queried and indexed in a MapReduce fashion using JavaScript. CouchDB also offers incremental replication with bi-directional conflict detection and resolution.
http://couchdb.apache.org/
CommonJS can be used for server side JavaScript, see here: http://www.commonjs.org/
NodeJS is another: http://nodejs.org/
Related
I have been using JS for simple front-end scripting for a while now, but am absolutely new to Node.js. After some surfing, I found out certain stuff about Node.js that it is fast, event-driven,uses modules, can be used both on server and client side, can be run from command line, etc.
As a project, the following task has been given to me:
"To develop a graph algorithm (such as minimum spanning tree) in javascript using node.js. Use the larger of the following graphs as inputs: http://snap.stanford.edu/data/ " [the link contains data from various network sites organised as nodes and edges and stored in .txt files]
Now I know how to implement a graph algorithm in a language (such as C), can even do it in JS using arrays. But I need some help regarding the "using node.js" part of the problem. What is its purpose in the problem ? Which of its features should I look up ?
Typically JS was made to run inside a browser.
Node.js is actually a javascript runtime invokable. You can invoke it from commandline. This means you can execute files of code from commandline like many other languages which you might be already familiar with. Beyond, that there is nothing much from your context.
But, yes it is fast, event-based, async and like server-scripting languages has server-handling capabilities inbuilt. That said it can be used for non-server contexts as well. Like computation in your case.
Node JS helps you to run backend logic, which is written on Javascript Language.
For example, in PHP, when you write backend code, you need some kind of application which will get all clients requests and run specific code to handle it. In PHP it will be done via Apache Server. In Java it will be done via Glassfish/JBoss/Tomcat.
Node JS is something like them, but for Javascript code.
Currently, I am developing a 2-player tetris game. Originally, I was planning to implement a client-server model in a mobile environment.
However, now I change into web game, which is accessible by a browser. Since I am not used to a web development, I want to know if client-server model is necessary in a web game.
To be honest, I am a little bit skeptical writing both client and server code since a browser does a job to connect to the server.
Is it possible to build a network-based game by using only one server without a client part?
Is it possible to build a network-based game by using only one server without a client part?
Nope. You need a client.
It doesn't matter if you're in the browser or writing a native application. Yes, the browser solves a lot of client problems for you - it implements HTTP for you, and it has display (CSS), content (HTML), and evented logic (JavaScript) that you can use. But you still need to write your client using those technologies.
Even if the browser exposed a call in javascript like this:
window.startPeterHwangsTetrisGame();
You still have a client. The client is 1 line of code, and it is exactly the above script*.
Realistically, you should look for a game-oriented web development tutorial and start there.
*(aside from the necessary HTML within which that javascript exists)
Well, in one sorta correct way, no, because you're not redesigning the browser, but nobody would say it like that. Web design includes a lot of code / markup used on the client (browser), and while your server is sending the browser the data, and that data is a mix of CSS, HTML, and JavaScript (as well as media like graphics and perhaps music), the browser is the piece of software doing the lifting on those pieces once it receives them. That data is selected by the server, so the logic for that is on the server, but this is what people would think of as "client design" in the context of a web application.
There are also a number of models (ways of arranging your programming designs) which would lead to cleaner code, and a lot of these would send a grouping of information (called a model) to the client (the browser) and then the browser would do some interpretation of how to use that data (called a view). This is a simplification since I don't think you're ready for a big dive into specific theories, but you could start with a JavaScript and HTML tutorial and then learn a server language:
Python is my favorite, but PHP is big as is Java (NOT to be confused with JavaScript), and I make my living doing C#. Really there are plenty of great choices.
One commentator recommended Node.js because you'd use JavaScript on the server with Node--just like for the client part (the response data you're sending to the browser). That's double duty, but I am partial to Python (as I said). Just pick something, and as you learn, you'll get to know what you like. If you change languages, it'll be easier to learn your second one.
Background
My background is high scale object oriented middleware and Applications development for embedded devices and desktops with C++. Now we need to create a high scale web-app for our startup.
Question
Request-response based and continuous polling based current web-development frameworks looks very primitive, inefficient.
I am looking for completely server-side object oriented and event based programming.
Here is an example it,
There is a persistent object named employeeManager on server,
methods of this object,
empList getAllEmployeeList();
empList getEmployeeOfDepartment(string strDept);
/*Some more */
events of this object
employeeAdded(empID);
employeeEdited(empID);
employeeRemoved(empID);
/*Some more */
Now, client side javascript should be able to call the methods of this (server-side) object and should be able to receive events of this object. We can have results of the method call in asynchronous mode. Framework should also provide a way so that view ( or html-js page ) can register for required server side events.
Is there any frameworks which works on this methodology. Anything like this on top of socketIO? Any framework which provides a good two way RPC between client javascript and sever side objects?
Try the following combo:
Node + socket.io + Backbone.Model + a bit of imagination.
I think the missing piece is a model like structure that can be used on both server side and client side. The model needs to synchronize state between server and client.
Here is an article that I find very interesting, and maybe you can use the technique described?
The article:
http://blog.andyet.com/2011/feb/15/re-using-backbonejs-models-on-the-server-with-node/
NodeJS and sockets.io. These can help achieve the desired effect.
Meteor is a Node.js based framework that uses sock.js for websocket communication and MongoDB for a database which is oriented for horizontally scalable apps. Meteor will pretty much do all the heavy lifting for you when it comes to client-server synchronization - you will not have to write any code for database syncing. The result is a minimal codebase with mainly your application's logic instead of the req/resp overhead. You can have a look at the examples here: http://meteor.com/examples/leaderboard
If you want cross-language RPC you might find Apache Thrift useful. I believe there's a Javascript client (but have never used it). You could build an RPC framework on top of Socket.IO as many others have pointed out, but it feels like painting a cat to look like a cow... i.e. fun, but not particular productive
I'm sure you have already, or have some legacy constraint, but in case you haven't I'd take a second to think about whether RPC is really the model you want to use. RPC leakily abstracts the existence of network latency, and as such bakes a few shaky assumptions into the foundations of your app. There's a fairly short and readable critique of RPC in general (by AST no less) that might be worth a read.
If you're familiar with C++, you may want to check out G-WAN. They have a great example using Comet (what you're looking for), and there are also Node.JS wrappers too.
G-WAN also allows for client-side applets written in whatever language you need too. So, for you, C++, might be just what you're looking for.
This is a very scalable web application server. From all the benchmarks I've seen, Node.JS doesn't scale well with high-concurrency (I may be wrong on this, if I am, please let me know, and provide me with the information). That being said, I've done things very similarly to what you're talking about doing. All I had to do was write a very simple wrapper to translate from JS to whatever language it was that I was using at the time (for me I've done it with PHP, MivaScript, SMT and C).
But the key (for me) was using Comet, to cut down on unnecessary polling of the server.
If I only want to use JavaScript on the client AND server side for my future web projects, how would this Javascript embracing tech stack look like? Are there any data stores/formats that are more idiomatic/JS friendly than the rest?
The idea is to use JavaScript for single page web apps where most of the rendering is done on the client.
The closest thing to a standard setup for this kind of app AFAIK is something close to this:
Node.js server app (often using the Express framework)
Backbone client app (typically with jQuery to control the interface)
Socket.io for communication between the two
Your choice of NoSQL database for persistence (there are Node.js adapters for all the common ones)
Fog Creek did a write-up of the stack they used to make Trello, which is essentially this.
(Incidentally, for clients that read a lot more than they write, I'd recommend taking a look at Server-Sent Events in lieu of Socket.io. They're a less heavy way to do one-way stream-based communication.)
There are lots of questions here, but you probably already have the answer to most of them. Not addressed is a good data layer -- look into MongoDB and Mongoose.js (a nice Node interface to MongoDB). Essentially, MongoDB is a persistent store for JSON objects, which works perfectly when you're programming with javascript. It uses javascript as its internal query language as well.
For an interesting take on this kind of setup in the real world, check out this article (I am affiliated with that company/product, but it's still a good read).
It would look like
node.js + any of the multitudes of client side javascript frameworks, jquery, sencha, yui, backbone, ember, sproutcore, etc....
Node.js on the server side is probably what you are looking for.
I'm developing a jQuery-based pivot table.
The goal is not a web app but a desktop-based application (C++). In my idea, data is retrieved by the application from the database, then passed to a html page and then showed through the pivot-table plugin.
There is no web server and the web page containing the plugin cannot access to the database.
So, how to pass data in an efficient way? I've seen other questions here on SO around this matter, but I think we're in a different scenario. Of course I can write the data in a txt/xml/js file, but I've experienced that for huge amounts of data, writing down files is costing a lot.
If you don't want to add support for the http protocol to your application, and you don't want to write to additional files, then IMO your best bet is to create a wrapping http server for your application. Then the javascript page can access the running wrapper which can talk to your "real" application.
You could create such a server relatively easily in python using the twisted framework, ruby using rails and the bundled webrick server, or the v8 Javascript engine node.js. (I'm sure there's dozens of other options out there too)
Which of there would be best for you will depend a lot on which languages you have experience with and what your deployment requirements are (supported OSes, existing installed applications, installation size, license terms on your software etc.)
Do you have a specific framework for your desktop app ? If you use Qt for the GUI, you can also integrate javascript quite easily.
http://efforts.embedded.ufcg.edu.br/qt/?p=84
You might be able to use named pipes to pass data to a static page.
It might also be better to just make your c++ program into a simple web server which opens a port, and have it generate the web page when the user goes to http://localhost:8080.