[Zope] RESPONSE.write

[Jure Koren]

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Hello, Zope users.

I have a python script that pulls e-mail from a pop3 server
and pushes it into an imap folder. Because this is a lenghty
process, I would like the user to be sure nothing went wrong,
so I display a list of messages being fetched, along with
their sizes, in real time.

I do this using calls to RESPONSE.write().

However, I've found out that it is impossible to use the
dtml-var tag in any dtml method i call from this python
script.

For example, in dtml method fetch_header i call this:
<dtml-var standard_html_header>

And I call fetch_header from fetch python script like this:
response.write(context.fetch_header(client=context, REQUEST=request))

If I remove the <dtml-var> and replace it with what the
standard_html_header dtml method contains, it works. If
there is a dtml-var tag, it breaks, and when it happens,
the connection to the browser is closed immediately, and
since using streaming mode by calling RESPONSE.write()
does not allow raising exceptions, I don't know what is
failing. There is no useful debugging information stored
anywhere that I know of. No exceptions are raised, or if
they are, dtml-try and try:... except: don't catch them.

Is there a document describing the behaviour of zope using
this RESPONSE.write() technique, with explanations of what
parts of zope are safe to use in this mode, and when?

Regards,
	Jure

- -- 
Jure Koren, n.i.
jure at aufbix.org
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