On Mar 3, 2008, at 10:32 AM, James Olin Oden wrote:

> On Mon, Mar 3, 2008 at 10:00 AM, Jeff Johnson <n3npq@mac.com> wrote:
>>
>>
>> On Mar 3, 2008, at 9:44 AM, Stefan Westmeier wrote:
>> Hi,
>>
>> just wanted to know if there is any chance that rpm packages can  
>> be piped
>> into the rpm command!?
>>
>>
>> Could be done, but there has to be some demonstrable need.
>>
>> For starters, a single package on stdin is a rather naive idea.  
>> Most rpm
>> transactions are composed of 100's or 1000's of packages, and
>> stdin is just not the best input method for concatenated packages
>> themselves.
> Jeff, there's actually enough markers to pull out multiple rpms from a
> single stream.  You know this though, I was just pointing it out for
> others.

If you mean that the sizes of all the pieces are known a priori, sure.
RPM can tell when the previous package stops and the next package starts
even if concatenated on stdin.

The problem is that a stdin stream is not at all a useful data
representation for multiple packages.

If there are any errors on the stream, then abandoning the installation
is the only possible error recovery.

And with multiple packages, a cache must be attempted, so that
all the metadata can be processed before the payloads are processed.

There are better data organizations than multiple concatenated
packages that permit restarting on a partially complete set of
packages, with more reliable cache handling, than reading
next hunk from stdin ...

> I'm with you though I'm not sure what the demonstrable need would
> be...unless the stream was coming from some other system across a
> network, ultimately.
>

... and all implementations that I can think of, including remote  
downloads,
are basically equivalent to reading stdin as a manifest of packages, not
the packages themselves.

But you know all this too ;-)

73 de Jeff