Problems starting Zappa (was Re: Express 3)

[Luke Hutchison]

Hi Stephane,

Thank you so much for taking the time to give such detailed replies to my questions. Your answers are incredibly helpful.

Unfortunately I can't try most of the stuff in your answers, because I'm hitting a problem in the version of zappajs in npm.

I installed node, then ran "npm install jappajs coffee-script", then set up a file starter.js that contained the following two lines:

require("coffee-script");

require("./app");

Then I took the code listed on https://npmjs.org/package/zappajs and saved it as app.coffee , then ran "node starter.js". I get the alert popup that says "hi", then there's a javascript exception that says "Uncaught TypeError: undefined is not a function" at Zappa.js:10 (which is the line where sammy.js is included). Following that I get "Uncaught ReferenceError: zappa is not defined" at client.js:1.

I tried including different versions (minified, not minified) of jquery and sammy, but that didn't fix the problem. I tried running on cloud9 in case something was wrong with my node install, but have the same problem. (My local node version is nodejs-0.9.5-9.fc18.x86_64.)

Three questions:

(1) Can you duplicate this error? Am I doing something wrong?

(2) Is launching Zappa from a file like the starter.js that I listed above the right way to do it? (I couldn't figure out any other way.)

(3) (unrelated to the above:) when running in Cloud9, the default port 3000 is blocked, apps need to run on the proxied port 8080. But I can't figure out how to pass the port number into zappa.js. What is the right way to pass in parameters?

Thank you,

Luke

On Sun, Mar 10, 2013 at 6:57 AM, <step...@shimaore.net> wrote:

Hello,

> I am investigating using ZappaJS for a project. The latest version
> mentioned on the website http://zappajs.org/ is 0.3.1; the email below
> talks about issues with integration of Express3 in version 0.3.9, although
> I found a version 0.4.18 in the zappajs/jappajs fork on GitHub. I hope the
> docs can be updated! :-)

Nobody currently working on the project owns the zappajs.org domain, so
there isn't much we can do until it expires.

[ That's https://github.com/zappajs/zappajs/issues/59 ]

> (1) Is version 0.4.18 now completely compatible with Express3? Are there
> remaining caveats like the ones in the quoted email below?

That email mostly documented problems with migrating code from Express 2
to Express 3; most of these are issues generic to Express 3 (especially
due to the fact that Express 3 moved to async templating). The one issue
specific to Zappa (dynamic views in filesystem) has been resolved for a
while.

> (2) I want to integrate passport.js or similar for authentication, and I
> want to be able to mark routes and sockets as only accessible to
> authenticated users, or to users with given roles (e.g. admins). What's the
> right way to do this with Zappa?

If I take the example on the passport.js Overview page[1] it should
translate into:

    @post '/login', passport.authenticate 'local',
      successRedirect: '/'
      failureRedirect: '/login'

[1] http://passportjs.org/guide/

In that example ZappaJS will wrap the callback, but it can still work as
usual with the (req,res,next) parameters.

The example on the Authorize page[2] would translate into:

    # Our authorization middleware.
    my_auth = passport.authorize 'twitter-authz',
      failureRedirect:'/account'

    # Middleware applies only to this route.
    @get '/connect/twitter/callback', my_auth, ->
      user = @req.user
      account = @req.account

      # etc.

[2] http://passportjs.org/guide/authorize/

and as usual in Express if you want to apply some middleware to all
requests:

    # Middleware applies to all routes.
    @use my_auth

> (3) I want to be able to reuse the HTTP auth for websockets, something like
> https://github.com/alphapeter/socket.io-express . Does Zappa need this sort
> of glue?

Inside ZappaJS Socket.IO code you can do

    @session (error,session) ->

which will retrieve the associated Express session.

By default this features is enabled in single-server mode out-of-the-box
as long as your page includes the ZappaJS client-side script.

However (and as far as I know this is unique to ZappaJS) it also works
if you split Express code on one pool of servers and Socket.IO code on
another pool of server, which should be more scalable.
Obviously it doesn't rely on cookies but uses a more complex algorithm[3]
which accesses both sides independently and then binds them through the
back-end database.

[3] https://github.com/zappajs/zappajs/blob/master/docs/share.png

There are complete, working examples demonstrating the distributed
feature.[4][5]
[4]
https://github.com/zappajs/zappajs/blob/master/examples/share_express.coffee
[5]
https://github.com/zappajs/zappajs/blob/master/examples/share_express.coffee

> (4) I want to enable CSRF protection for websockets, which is built into
> connect.js, but has to be added after the cookieParser() and session()
> middleware: http://www.senchalabs.org/connect/middleware-csrf.html . Does
> Zappa enable CSRF protection?

To follow the example on that web page you would do:

    @use 'cookieParser', session:{secret:'keyboard cat'},
      'bodyParser', 'csrf'

> (I assume not, because there is no user
> authentication built in by default, as far as I can tell?)

ZappaJS is just a wrapper around Express and Socket.IO, with (I hope!)
sensible defaults but no hard opinions on how you should do your job. :)

> (5) Is it possible to enable SPDY in Zappa?

I've never looked into it but judging from the doc[6] it shouldn't be too
hard to integrate.

[6] https://github.com/indutny/node-spdy

In the meantime the following might work, based on the example under
"usage with express" on that page:

    # Use `zappa.app` instead of `zappa.run`
    zapp = zappa.app ->
      # Your regular ZappaJS code here

    server = spdy.createServer options, zapp.app

    server.listen 443

> (More generally, how does SPDY interplay with SSL, WebSockets,
> HTTP-to-WebSocket handoff, user auth etc. in this context? I'm under the
> impression I need to implement everything twice: HTTP[+SSL][+WebSockets]
> plus SPDY routes to handle the two cases separately?)

My reading of SPDY is that it is a framer that replace multiple TCP
connections to a server with a single one and multiplexes requests over
that connection. Not sure what "SPDY routes" would mean in that case
(the only API available is server-side `push`), the same way that you
don't differentiate HTTP vs HTTPS requests today for example
(i.e. Express routing is based on URIs, not on protocols).
S.

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[Luke Hutchison]

On Tue, Mar 12, 2013 at 12:06 AM, Luke Hutchison <luke....@gmail.com> wrote:

(1) Can you duplicate this error? Am I doing something wrong?

Update: solved the first problem: there was a missing ';' at the end of the included vendor/socket.io.min.js -- created issue 73 to track it: https://github.com/zappajs/zappajs/issues/73

(2) Is launching Zappa from a file like the starter.js that I listed above the right way to do it? (I couldn't figure out any other way.)

(3) (unrelated to the above:) when running in Cloud9, the default port 3000 is blocked, apps need to run on the proxied port 8080. But I can't figure out how to pass the port number into zappa.js. What is the right way to pass in parameters?

Still looking for answers to these other two questions. Thank you!

 

[step...@shimaore.net]

Hi Luke,

> (1) Can you duplicate this error? Am I doing something wrong?

You're not, it should work and it doesn't. Apparently some subtlety in
loading Sammy which wasn't there in previous versions.

In my limited tests I was able to get it to work by changing this line:

scripts: '/zappa/Zappa-simple.js /zappa/sammy.js /index.js /client.js'

This loads Sammy independently and makes it happy.

I opened issue #74 on this.
[#74] https://github.com/zappajs/zappajs/issues/74

And I need to run those client-side tests before I release new versions,
that would have caught this problem earlier. I apologize.

> (2) Is launching Zappa from a file like the starter.js that I listed above
> the right way to do it? (I couldn't figure out any other way.)

You can start it with the `coffee` interpreter:

coffee app.coffee

You can get access to the `coffee` interpreter by installing it
globally:

sudo npm -g install coffee-script

or (I tend to prefer this for development) by adding the location of the
binaries of your local npm packages to your PATH (this might work on
Windows with a different syntax); for example my `.profile` contains:

PATH="$HOME/node_modules/.bin:$PATH"

Assuming `coffee` is in your path you can then add:

#!/usr/bin/env coffee

at the top of your .coffee files; and mark them executable to get working
scripts, which you can start with

./app.coffee

for example. (This last bit is a standard Unix trick, this would work
with Node.js scripts as well.)

> (3) (unrelated to the above:) when running in Cloud9, the default port 3000
> is blocked, apps need to run on the proxied port 8080. But I can't figure
> out how to pass the port number into zappa.js. What is the right way to
> pass in parameters?

Assuming

zappa = require 'zappajs'

`zappa` is actually a shortcut for `zappa.run`, so you can pass the port
this way:

zappa 8080, ->
# Zappa code

There are more options, see
http://zappajs.github.com/zappajs/docs/reference#zapparun
for the complete list.

Thank you for the bug report and hanging in there!
S.

[Luke Hutchison]

On Tuesday, March 12, 2013 2:00:40 AM UTC-7, Stephane wrote:

Hi Luke,

> (1) Can you duplicate this error? Am I doing something wrong?

You're not, it should work and it doesn't. Apparently some subtlety in
loading Sammy which wasn't there in previous versions.

In my limited tests I was able to get it to work by changing this line:

    scripts: '/zappa/Zappa-simple.js /zappa/sammy.js /index.js /client.js'

This loads Sammy independently and makes it happy.

I opened issue #74 on this.
[#74] https://github.com/zappajs/zappajs/issues/74

Presumably this was just the same problem as #73, it was actually socket.io not being terminated with ';', and had nothing to do with sammy.js.

 

> (2) Is launching Zappa from a file like the starter.js that I listed above
> the right way to do it? (I couldn't figure out any other way.)

You can start it with the `coffee` interpreter:

    coffee app.coffee

Works great, thanks. (Sorry to ask you to explain things that are that basic!)

> (3) (unrelated to the above:) when running in Cloud9, the default port 3000
> is blocked, apps need to run on the proxied port 8080. But I can't figure
> out how to pass the port number into zappa.js. What is the right way to
> pass in parameters?

Assuming

    zappa = require 'zappajs'

`zappa` is actually a shortcut for `zappa.run`, so you can pass the port
this way:

    zappa 8080, ->
      # Zappa code

That works too. I tried a lot of things like that before asking, and tried looking at the compiled JS code etc. -- it's all making more sense now.

 

There are more options, see
    http://zappajs.github.com/zappajs/docs/reference#zapparun
for the complete list.

Thank you!