[Zope] a batch of inSaNitY!

[Jonathan]

----- Original Message ----- 
From: "Programmer" <programmer at paradigm-corp.com>
To: <zope at zope.org>
Sent: Wednesday, May 30, 2007 4:44 PM
Subject: [Zope] a batch of inSaNitY!


> Hi
>
> I am about to go stark, raving, frothing mad with the DTML-IN batching.
> Is there a known (or unknown) bug with this?
>
> I have searched and read everything I can find about this and no luck.
> The problem is with carrying the query terms over from one batch page to
> the next. Right now I am using the script found here:
> http://mail.zope.org/pipermail/zope-collector-monitor/2003-May/002001.ht
> ml
>
> Except I changed,
>
> <dtml-let
>  batch="_.range(100, 180)"
>  batch_size="10"
>  batch_start="REQUEST.get('batch_start',1)">
>
> To
>
> <dtml-let
>  batch="myZSQLMethod1"
>  batch_size="10"
>  batch_start="REQUEST.get('batch_start',1)">
>
> The mySQLMethod1 takes two params which the search form supplies to
> REQUEST. This works great. The pagination works beautifully. However,
> when I use the very same result script with myZSQLMethod2 (same DB
> table), which takes 5 params (all optional) the pagination breaks and
> no-longer passes the query terms.
> I have checked and rechecked both scripts and both forms. The
> ZSQLMethods both test good. I am out of ideas. For the life of me I
> cannot figure out why I'm losing my query terms in one and not the other
> when the two are almost identical.
> Care to enlighten me with your collective wisdom?

In similar situations I have done the following:

1) call a python script/external method which: (i) does the db search; (ii) 
formats the results as required for display; (iii) returns a tuple that 
contains: list of search results, url parameters for 'previous' link; url 
parameters for 'next' link; url parameters for 'first link'; url parameters 
for 'last' link

2) use a dtml method to call the script/ext.method like

<dtml-let rStat="mySearchRoutine(parm1, parm1, ...)">

  <dtml-in "rStat[0]">
      display code here eg.  <dtml-var sequence-item><br>
      or could be an html/css table, etc.

     <dtml-if sequence-end>
         <a href="...?<dtml-var "rStat[1]">">previous</a>
         <a href="...?<dtml-var "rStat[2]">">next</a>
         <a href="...?<dtml-var "rStat[3]">">first</a>
         <a href="...?<dtml-var "rStat[4]">">last</a>
      </dtml-if>

  </dtml-in>
</dtml-let>

This greatly simplifies the dtml and facilitates debugging and future 
modifications.

hth

Jonathan