5. Blocking / Threads
vs Callbacks
var result = db.query(“select * from T”)
print(result)
db.query(“select * from T”, function (result) {
print(result)
})
vs
13. The web in 2014
• Rich applications
– Real time updates
– Single page
• Short development cycles
14.
15.
16.
17.
18. Seven Principles of Meteor
Data on the Wire. Send data, not HTML, over the network. Let the client
decide how to render it.
One Language. Write both the client and the server parts of your
interface in JavaScript.
Database Everywhere. Use the same transparent API to access your
database from the client or the server.
Latency Compensation. On the client, use prefetching and model
simulation to make it look like you have a zero-latency connection to the
database.
19. Seven Principles of Meteor
Full Stack Reactivity. Make realtime the default. All layers, from
database to template, should make an event-driven interface available.
Embrace the Ecosystem. Meteor is open source and integrates, rather
than replaces, existing open source tools and frameworks.
Simplicity Equals Productivity. The best way to make something
seem simple is to have it actually be simple. Accomplish this through clean,
classically beautiful APIs.
20. Getting Started
Install Node and Meteor
(Mac / Linux) curl https://install.meteor.com | /bin/sh
(Windows) http://win.meteor.com/
22. File Structure
• /server - runs on the server
• /client - runs on the client
• /, /common - runs on both
• static assets (fonts, images, etc.) go
in /public
Javascript is / was the only ubiquitous language on the browser. Probably because it came out so long ago
However javascript used to be very slow
Noticeably slow on the client / so servers would render html templates and then send them to the client (page reloads or ajax)
Too slow to use if you want to have a performant server
Then along Chrome and the V8 javascript engine
Fast new generation of Javascript engines gave the client far more power for user experience.
Along with the HTML5 spec’s new features, they basically replaced need for plugins (like Flash and Sliverlight)
V8 is so fast, that it enables us to use Javascript on the server.
Node, which runs off v8 engine is a server side Javascript framework.
It was invented by Ryan Dahl because he wanted to built web sites with push capabilities like Gmail (or chat application).
Many of the current programming frameworks allowed for async code, but it is difficult to use.
So he build Node, to bake non-blocking IO into the server from the ground up.
What does that all mean?
------
History of Node: http://www.youtube.com/watch?v=SAc0vQCC6UQ
First one either
Blocks entire process
Implies multiple execution stacks
Complicated manage locks on shared data
Threads are expensive
Second one is non-blocking, so it can run on an event loop.
Javascript’s feature’s were built for an event loop, things like callbacks and closures. The browser runs javascript in an event loop. So it is non-blocking from the ground up.
----
From original Node.js presentation http://www.youtube.com/watch?v=ztspvPYybIY
Traditional server, if you make a request then access the database or some other services, the thread will stay blocked until your IO operations are completed.
This does not scale well when you are doing long polling and have 1000s of connections.
Node fixes that with it’s event loop and non-blocking IO.
Since JavaScript did not have an existing I/O api, he was able to build a non-blocking, event driven I/O convention into it from the ground up.
It’s actually hard to write blocking code with node.
1 language = keep it simple
We get simplicity. This is the main reason we are using meteor / node in this class.
- Get proficient with one language then reuse your skillset on the client and server
Reuse code client & server
Javascript is the most popular language, at least on GitHub. So you can reuse a lot of other people’s code
Old internet formula for success
How do you leverage the power of javascript on the client and javascript on the server?
Meteor is a platform built on top of Node.js for building real-time web apps of 2014.
Google, facebook, and twitter have set the bar for people to expect real time, rich applications.
- Meteor is the platform rails would be if it were built today on top of node.
- Allow you to use JavaScript on the client and on the server. Can share code between both environments.
- Very powerful and very simple platform that abstracts away many of the usual hassles and pitfalls of web app development.
- In other frameworks real-time is hard. Meteor makes it easy.
But don’t take my word for it.
Consulting companies love it
Differential.io
percolatestudio.com
And so do startups
respond.ly
https://www.youtube.com/watch?v=jscINbvWoDg
https://lookback.io/
Our company, Structural is built in meteor. Details coming soon….
DDP protocol allows anything to connect to Meteor -- from native mobile apps to Arduinos.
DDP clients are available in Android, Objective C, Java, C#, Python, Ruby, Dart, AS3… http://www.meteorpedia.com/read/DDP_Clients
http://nodejs.org/download/
.meteor/ used by Meteor
.meteor/packages and .meteor/release files are the only two we will modify, but not today
/lib loaded first
main.* file is loaded last