VCL language

[Poul-Henning Kamp]

In message <1543.193.213.34.102.1143676134.squirrel at denise.vg.no>, "Anders Berg" writes:

I think a large part of the solution is to come up with some clear
examples to show people how to do things.

Is this an improvement ?

1     backend default {
2         set backend.ip = 10.0.0.1;
3     }
4
5     proc main {
6	  if (req.request != "GET" && req.request != "HEAD") {
7	      pass_through;
8	  }
9	  lookup_object;
10	  if (obj.valid) {
11            finish;
12	  }
13	  fetch;
14        if (obj.url ~ "[.]hbs$") {
15            obj.ttl = 5m;
16            obj.cacheable = true;
17        } elif (obj.url ~ "[.]jpg$" || obj.url ~ "[.]gif$") {
18            obj.ttl = 1w;
19            obj.cacheable = true;
20        } elif (obj.url ~ "/poor_written") {
21            obj.ttl = 5m;
22            obj.cacheable = true;
23        }
24	  if (obj.cacheable) {
25	      insert;
26	  }
27    }

14,17,20:  a '.' in a regexp means "any character", putting it in [.]
	   is a readable way to escape it.  Because we use strings
	   enclosed in double-quotes, the backslash-escape would be
	   "\\.jpg$".  The trailing '$' is to avoid false matches.

	   Of course, we could also add a 
		if (obj.suffix = ".hbs")
	   if we wanted to make this easier/faster.

15,16:	   We could let the "obj.cacheable = true" be implicit when
	   obj.ttl is set, I can't really see why we shouldn't ?

17:        Another way to write it could be:

	   if (obj.content_type ~ "image/") {

So with those changes it would look like this:

1     backend default {
2         set backend.ip = 10.0.0.1;
3     }
4
5     proc main {
6	  if (req.request != "GET" && req.request != "HEAD") {
7	      pass_through;
8	  }
9	  lookup_object;
10	  if (obj.valid) {
11            finish;
12	  }
13	  fetch;
14        if (obj.suffix = ".hbs") {
15            obj.ttl = 5m;
16        } if (obj.content_type ~ "image/") {
17            obj.ttl = 1w;
18        } elif (obj.url ~ "/poor_written") {
19            obj.ttl = 5m;
20        }
21	  if (obj.cacheable) {
22	      insert;
23	  }
24    }


-- 
Poul-Henning Kamp       | UNIX since Zilog Zeus 3.20
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FreeBSD committer       | BSD since 4.3-tahoe    
Never attribute to malice what can adequately be explained by incompetence.