Книга: Linux Network Administrator Guide, Second Edition

Reading an Article from a Group

Reading an Article from a Group

While it is normally most efficient to separately transfer the headers and bodies of selected articles, there are occasions when we are better off transferring the complete article. A good example of this is in applications through which we want to transfer all of the artices in a group without any sort of preselection, such as when we are using an NNTP cache program like leafnode.[134]

Naturally, NNTP provides a means of doing this, and not surprisingly, it operates almost identically to the head command as well. The article command also accepts an article number or message ID as an argument, but returns the whole article including its header:

article 1
220 1 ‹[email protected]› article
Path: news.vbrew.com!not-for-mail
From: [email protected]
Newsgroups: junk
Subject: test message number 1
Date: 26 Apr 1999 22:08:59 GMT
Organization: The Virtual brewery
Lines: 2
Message-ID: ‹[email protected]›
NNTP-Posting-Host: localhost
X-Server-Date: 26 Apr 1999 22:08:59 GMT
Body:
Xref: news.vbrew.com junk:1
This is a test message, please feel free to ignore it.
.

If you attempt to retrieve an unknown article, the server will return a message with an appropriately coded response code and perhaps a readable text message:

article 4
423 Bad article number

We've described how the most important NNTP commands are used in this section. If you're interested in developing software that implements the NNTP protocol, you should refer to the relevant RFC documents; they provide a great deal of detail that we couldn't include here.

Let's now look at NNTP in action through the nntpd server.

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