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Solved: Randomly picking a product
Hello users,
I solved my problem in a two days work at this weekend. It will not be the
everlasting solution, but it's enought for my needs, and perhaps for many
others too.
Here's what I did:
At first I wrote a new User-defined-Tag and put it into minivend.cfg like
this:
UserTag rand_prod Order max_num
UserTag rand_prod Routine <<EOF
sub{
my ($tmp) = @_;
srand();
$tmp = rand($tmp);
$tmp= int($tmp);
if ($tmp==0){
return 1}
else{
return $tmp}
}
EOF
The UserTag "rand_prod" returns a random number from 0 to "max_num".
"max_num" is given by the [db-count] Tag I found at the end of minivend.cfg
(it's not in the documentation!)
Then I edited the products.asc and filled in a new column named "row" with
an indexing number for each record from 1 to ...... end of records (50 in my
case) in the rows.
In the top of my html-page I inserted following:
<body MV="body 1">
[comment] the following line gets the maximum record-number
from products.asc to the variable "db_max" , once on
the page![/comment]
[value name=db_max set="[db-count]" hide=1]
[comment] the next line calls the User-defined-Tag
and puts the returning random number to
"rand_num"[/comment]
[value name=rand_num set="[rand_prod max_num='[value db_max]']"
hide=1]
[loop search="se=[value rand_num]
sf=row
op=em
"]
<img src="[loop-field image]" width="150"><br>
[loop-field title]<br>
[loop-field description]
[/loop]
The [loop-search] Tag did the rest. That was nearly all. - Nearly? Yes!
I tried to put that source more than once into my html-page. That was really
twicky. Every second third and so on, I put that source into the page, the
page did show everytimes the same record. What was that?
After a whole day of confused looking up that problem I had the right idea:
When the UserTag [rand_prod] is invoked at the top of the page more than one
time a second, the same random number appears because the srand()-function
is depending on time by seconds. Take care not to do the same mistake than I
did!
For that I changed my code like this:
[value name=db_max set="[db-count]" hide=1]
[value name=rand_num1 set="[rand_prod max_num='[value db_max]']"
hide=1]
[value name=rand_num2 set="[calc]abs([value rand_num1]-20)[/calc]"
hide=1]
[value name=rand_num3 set="[calc]abs([value rand_num1]-31)[/calc]"
hide=1]
[value name=rand_num4 set="[calc]abs([value rand_num1]-42)[/calc]"
hide=1]
[loop search="se=[value rand_num1]
sf=row
op=em
"]
<img src="[loop-field image]" width="150"><br>
[loop-field title]<br>
[loop-field description]
[/loop]
[loop search="se=[value rand_num2]
sf=row
op=em
"]
<img src="[loop-field image]" width="150"><br>
[loop-field title]<br>
[loop-field description]
[/loop]
and so on. - And it works fine for my needs!
I would be interested, if someone tries with some more records, if it
important slows the page. Give me your feedback, please.
Thank you all for your attention and I hope I could help and someone else
can help _me_ another time.
Sincerely
Holger Matschinski
