Re: Reading URLs with POST data vs. w/out POST

From:

=?ISO-8859-1?Q?Arne_Vajh=F8j?= <arne@vajhoej.dk>

Newsgroups:

comp.lang.java.programmer

Date:

Fri, 11 Jan 2008 23:18:09 -0500

Message-ID:

<47883f7e$0$90270$14726298@news.sunsite.dk>

Hal Vaughan wrote:

I'm working a simple method to read web pages and experimenting with a few
aspects.

I've noticed if the URL contains POST data (and I'm just specifying the POST
data in the URL), when I try URLConnection().getContentLength(), I often
get a length of -1. I don't see this happen on any web pages without any
post data.

Is this because the page is generated dynamically and the server may not be
reporting the length for a posted page but is reporting it for a static
page?

I've tested different configurations in programs and even copied different
examples from web pages to test this out, but the effect is code
independent.

Here are two example pages:

Length reported correctly:
<http://www.archive.org/download/361003WorldSeriesGiantsVsYankees/361003WorldSeriesGiantsVsYankees_files.xml>

Length reported as -1:
<http://www.archive.org/search.php?page=1&query=collection%3Aoldtimeradio&sort=title>

I don't think this is a Java language issue, but more a factor of what data
one gets back from a server. Am I right about this? Is it a server issue?
The server, according to Netcraft, is running Apache.

When you talk about "URL contains POST data" I assume that you means
"URL with query string" (the data in a POST is not in the URL !).

Java docs for getContentLength() says:

#Returns:
# the content length of the resource that this connection's URL
# references, or -1 if the content length is not known.

The HTTP standard says about Content-Length header:

# In HTTP, it
# SHOULD be sent whenever the message's length can be determined prior
# to being transferred, unless...

It sounds very plausible that:
* the byte count can easily be detected for static content
* the byte count can not as easily be detected for scripts

Arne