Hi ho,
I am playing with the event store by pushing the live events from Github into the store as they happen and trying to report on stuff as they happen, I have a few questions - some of which I have answered for myself by searching through the mailing list and a few which are still open
I am going to try and create a static web page (if possible, tell me if it is not) that looks something like
So for the first one, I have a projection that looks like
fromAll().whenAny(function(s, e) {
if(e.body && e.body.repo) {
var date = new Date(e.body.created_at)
var dateString = date.getUTCFullYear() + '' + date.getUTCMonth() + '' + date.getUTCDate()
linkTo('day-' + dateString, e)
}
}
)
Rob,
do you have system projections running?
-yuriy
I do
And the stream per day does contain the right data, for example
oops, hit return too quickly
streams/day-20121112?format=json
Gives me a nice list of events
And a typical event linked by this has the right data, for example
{
eventStreamId: “github”,
eventNumber: 5386,
eventType: “PushEvent”,
data:
{
created_at: “2012-12-12T16:54:57Z”,
type: “PushEvent”,
actor:
{
id: 17243,
gravatar_id: “f3de83804a52754963bf99633c097c65”,
login: “algernon”
},
I’m thinking that I’ve just written the projection code wrong - I’m going off whatever I’ve found in the mailing list so it’s out of date and not fully understood 
Check that $ce-day stream is not empty. It should be populated by the system projection.
The fromCategory(‘day’) actually reads the $ce-day stream.
question:
$ce_day has links to the daily streams, rather than the events themselves
Am I misunderstanding the use of the category method?
Rob,
I think I know what the problem is. When you do foreachStream over a category stream (which holds event links), it does foreachStream over the the original streams where the events are stored.
I’ll address this in new builds.
-yuriy
You think it’s not something I’m doing wrong but rather a behaviour of the ES itself that needs changing?
Can I clarify how this is supposed to work then, it is my understanding from the above discussion that
Using linkTo with something-X will create a stream called something-X for each X that exists
That stream will contain a link to the original event for every event that is passed in with linkTo
Because I named the stream something-X, the built in streams will create a stream called $ce-something
That $ce-something contains a link to each of the streams that was created above (/stream/something-x/)
When doing fromCategory and foreachStream what I am saying is
In this case, that would mean running the projection above over the stream
/streams/day-20121112/
at least that’s the desired behaviour, but for some reason this isn’t the case and soon it will be and my projection will work?
Rob,
you are right. Disregard my previous e-mail. My fix will not help you in this case.
‘linkTo’ does not write “link to link”, but writes link to the original event.
Let me check how this can be addressed.
-yuriy
Further to the above, if I go and do
.whenAny(function(s, e) {
if(e.body && e.body.repo) {
var date = new Date(e.body.created_at)
var hour = date.getUTCHours()
if(typeof s[hour] === 'undefined')
s[hour] = 0
s[hour]++
}
})
Er, pasted that badly, I meant
fromStream('day-20121112')
.whenAny(function(s, e) {
if(e.body && e.body.repo) {
var date = new Date(e.body.created_at)
var hour = date.getUTCHours()
if(typeof s[hour] === 'undefined')
s[hour] = 0
s[hour]++
}
})
I think foreachMatching(f(stream metadata)) could be very powerful
It would make this kind of little trick much easier
foreachMatching(function(meta) {
return meta.name.indexOf(‘day-’) === 0
})
And could do other pretty neat things
In the meantime, is there any way I can get the per-day chart-data that I’m looking for based on the above?