AJAX responses

Rails
1

Does anyone know if it’s possible to do multiple AJAX responses to a
single request in Rails? I did some googling but didn’t find anything
extremely helpful.

Thanks.

2

Bob wrote:

Does anyone know if it’s possible to do multiple AJAX responses to a
single request in Rails? I did some googling but didn’t find anything
extremely helpful.

What do you mean? One HTTP request gets one response. That’s the way
the protocol works

Thanks.

Best,
–Â
Marnen Laibow-Koser
http://www.marnen.org
[email protected]

3

On 10 Feb 2010, at 17:18, Marnen Laibow-Koser wrote:

Does anyone know if it’s possible to do multiple AJAX responses to a
single request in Rails? I did some googling but didn’t find
anything
extremely helpful.

What do you mean? One HTTP request gets one response. That’s the way
the protocol works

Indeed, every HTTP request only yields one response. What you are
looking for is a PeriodicalExecuter or PeriodicalUpdater (javascript
polling every xx seconds). Another way to go is a push notification
system, which is more difficult to implement and host (forget about
hosting it on a shared host). Juggernaut or Comet should help you out
there. But unless you really know what you are doing, the periodical
execution way is going to give you the least amount of problems.

Best regards

Peter De Berdt

4

I have a class that compares invoice totals for a month and calculates
the dollars saved. The downside is it takes about 1 second per
invoice per month to calculate so it’s taking a considerable amount of
time to display a complete report especially if you run it for a two
year period (48 seconds). What I was hoping to do is to make an AJAX
request for the report and respond with each row (or month in this
case) of the comparison table as they finish calculating. I had a
feeling this would be pretty problematic to do…

5

In my opinion, there’s three ways to go about this:

  1. Pregenerate reports in low traffic/low CPU usage times, like
    overnight. Since you are making monthly invoicing reports, the reports
    should stay the same anyway. When the user requests a certain range,
    assemble the cached pieces into on nice report.
  2. Fire a PeriodicalExecuter to a controller method. The first time,
    it starts the report generation in a background process, every
    subsequent request will load the generated report lines into the view
  3. Use Juggernaut or Comet to push the data to the client. Fire an
    event to start the report generation in a background process and then
    route to the clients that are subscribed to the right Juggernaut/Comet
    channel.

Personally, unless realtime reports are an absolute necessity, I would
just go for a nightly report generation cron tab. It will provide the
best experience to your end user and won’t put a serious strain on the
server overall during peak traffic times.

On 10 Feb 2010, at 20:08, Bob wrote:

On Feb 10, 11:29 am, Peter De Berdt [email protected] wrote:

the protocol works

Indeed, every HTTP request only yields one response. What you are
looking for is a PeriodicalExecuter or PeriodicalUpdater (javascript
polling every xx seconds). Another way to go is a push notification
system, which is more difficult to implement and host (forget about
hosting it on a shared host). Juggernaut or Comet should help you out
there. But unless you really know what you are doing, the periodical
execution way is going to give you the least amount of problems.

Best regards

Peter De Berdt