[PATCH] cgit.css: add dynamic age update

[andy at warmcat.com (Andy Green)]

On June 24, 2018 7:52:53 PM GMT+08:00, John Keeping <john at keeping.me.uk> wrote:
>Subject should be "cgit.js: " not cgit.css!
>
>On Sun, Jun 24, 2018 at 03:59:51PM +0800, Andy Green wrote:
>> This patch updates the emitted "ages" dynamically on the client side.
>> 
>> After updating on completion of the document load, it sets a timer
>> to update according to the smallest age it found.  If there are any
>> ages listed in minutes, then it will update again in 10s (this can
>> never happen more than twelve times on a given page then).  When the
>> most recent age is in hours, it updates every 5m.  If days, then
>> every 30m and so on.
>> 
>> This keeps the cost of the dynamic updates at worst once per 10s
>> and trending towards being trivially cheap after a couple of minutes.
>> The updates are done entirely on the client side without contact
>> with the server.
>> 
>> To make this work reliably, since parsing datetimes is unreliable in
>> browser js, the unix time is added as an attribute to all age spans.
>> 
>> To make that reliable cross-platform, the unix time is treated as a
>> uint64_t when it is formatted for printing.
>> 
>> The rules for display conversion of the age is aligned with the
>> existing server-side rules in ui-shared.h.
>> 
>> If the client or server-side time are not synchronized by ntpd etc,
>> ages shown on the client will not relate to the original ages
>computed
>> at the server.  The client updates the ages immediately when the
>> DOM has finished loading, so in the case the times at the server and
>> client are not aligned, this patch changes what the user sees on the
>> page to reflect patch age compared to client time.
>> 
>> If the server and client clocks are aligned, this patch makes no
>> difference to what is seen on the page.
>> 
>> Signed-off-by: Andy Green <andy at warmcat.com>
>
>If we're going to start depending on JS, should we take the robust

This does not "start depending on JS".

For browsers with JS disabled, or with cgit.js disabled, it just displays what the server sent exactly as it does now.

>approach to this and never generate relative times on the server?  Or
>do
>so only for <noscript>?

There's nothing particularly wrong with generating these "age" links serverside... but they rot.

>I'd really like to here other people's opinions on this.

I'm posting them here to get comment...

>Personally, I'm slightly negative because while I do regularly use some
>sites that take this approach (including having long-lived tabs open on
>pages like this), I always end up refreshing the page anyway when I go
>back to the tab, because new content doesn't load without doing so. 
>
>So I'm not sure what this tells me except "it's been at least N

It doesn't tell you that at all.

There's another patch on warmcat cgit that actually does that, it adds an 'age' to the footer.

What it does is if you looked in the evening at something recently pushed, when you look in the morning it doesn't surprise you with saying something was pushed five minutes ago... it will say something pushed 10h ago by then.  And the way it does it, it's pretty cheap.

>{seconds,minutes,hours,days} since you last refreshed this page".  And
>the first thing I'm going to do is hit refresh anyway.

If you don't want it, no worries.

-Andy

>> ---
>>  cgit.h      |    1 +
>>  cgit.js     |   58
>++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
>>  ui-shared.c |    2 +-
>>  3 files changed, 60 insertions(+), 1 deletion(-)
>> 
>> diff --git a/cgit.h b/cgit.h
>> index 2579ce4..9b21919 100644
>> --- a/cgit.h
>> +++ b/cgit.h
>> @@ -24,6 +24,7 @@
>>  #include <utf8.h>
>>  #include <notes.h>
>>  #include <graph.h>
>> +#include <inttypes.h>
>>  
>>  /* Add isgraph(x) to Git's sane ctype support (see
>git-compat-util.h) */
>>  #undef isgraph
>> diff --git a/cgit.js b/cgit.js
>> index e2c3799..e13faf2 100644
>> --- a/cgit.js
>> +++ b/cgit.js
>> @@ -145,6 +145,61 @@ function cgit_line_range_click(e) {
>>  	cgit_copy_clipboard(cp);
>>  }
>>  
>> +/* this follows the logic and suffixes used in ui-shared.c */
>> +
>> +var cgit_age_classes = [ "age-mins", "age-hours", "age-days",   
>"age-weeks",    "age-months",    "age-years" ];
>> +var cgit_age_suffix =  [ "min.",     "hours",     "days",       
>"weeks",        "months",        "years",         "years" ];
>> +var cgit_age_next =    [ 60,         3600,        24 * 3600,     7 *
>24 * 3600,  30 * 24 * 3600,  365 * 24 * 3600, 365 * 24 * 3600 ];
>> +var cgit_age_limit =   [ 7200,       24 * 7200,   7 * 24 * 7200, 30
>* 24 * 7200, 365 * 25 * 7200, 365 * 25 * 7200 ];
>> +var cgit_update_next = [ 10,         5 * 60,      1800,          24
>* 3600,      24 * 3600,       24 * 3600,       24 * 3600 ];
>> +
>> +function cgit_render_age(e, age)
>> +{
>> +	var t, n;
>> +
>> +	for (n = 0; n < cgit_age_classes.length; n++)
>> +		if (age < cgit_age_limit[n])
>> +			break;
>> +
>> +	t = Math.round(age / cgit_age_next[n]) + " " + cgit_age_suffix[n];
>> +
>> +	if (e.textContent != t) {
>> +		e.textContent = t;
>> +		if (n == cgit_age_classes.length)
>> +			n--;
>> +		if (e.className != cgit_age_classes[n])
>> +			e.className = cgit_age_classes[n];
>> +	}
>> +}
>> +
>> +function cgit_aging()
>> +{
>> +	var n, next = 24 * 3600,
>> +	    now_ut = Math.round((new Date().getTime() / 1000));
>> +
>> +	for (n = 0; n < cgit_age_classes.length; n++) {
>> +		var m, elems =
>document.getElementsByClassName(cgit_age_classes[n]);
>> +
>> +		if (elems.length && cgit_update_next[n] < next)
>> +			next = cgit_update_next[n];
>> +
>> +		for (m = 0; m < elems.length; m++) {
>> +			var age = now_ut - elems[m].getAttribute("ut");
>> +
>> +			cgit_render_age(elems[m], age);
>> +		}
>> +	}
>> +
>> +	/*
>> +	 * We only need to come back when the age might have changed.
>> +	 * Eg, if everything is counted in hours already, once per
>> +	 * 5 minutes is accurate enough.
>> +	 */
>> +
>> +	window.setTimeout(cgit_aging, next * 1000);
>> +}
>> +
>> +
>>  /* line range highlight */
>>  
>>  document.addEventListener("DOMContentLoaded", function() {
>> @@ -152,6 +207,9 @@ document.addEventListener("DOMContentLoaded",
>function() {
>>  	var e = document.getElementById("linenumber_td");
>>  	if (e)
>>  		e.addEventListener("click", cgit_line_range_click, true);
>> +
>> +	cgit_aging();
>> +
>>  }, false);
>>  window.addEventListener("hashchange", function() {
>>  	cgit_line_range_highlight();
>> diff --git a/ui-shared.c b/ui-shared.c
>> index 836c590..8567c06 100644
>> --- a/ui-shared.c
>> +++ b/ui-shared.c
>> @@ -670,7 +670,7 @@ const struct date_mode *cgit_date_mode(enum
>date_mode_type type)
>>  static void print_rel_date(time_t t, int tz, double value,
>>  	const char *class, const char *suffix)
>>  {
>> -	htmlf("<span class='%s' title='", class);
>> +	htmlf("<span class='%s' ut='%" PRIu64 "' title='", class,
>(uint64_t)t);
>>  	html_attr(show_date(t, tz, cgit_date_mode(DATE_ISO8601)));
>>  	htmlf("'>%.0f %s</span>", value, suffix);
>>  }
>> 
>> _______________________________________________
>> CGit mailing list
>> CGit at lists.zx2c4.com
>> https://lists.zx2c4.com/mailman/listinfo/cgit