16 NNTP: Newsgroup Protocol
16.1 Connection and Operations
struct
(struct communicator (sender receiver server port) #:extra-constructor-name make-communicator) sender : output-port? receiver : input-port? server : string? port : (integer-in 0 65535)
Once a connection to a Usenet server has been established, its state
is stored in a communicator, and other procedures take
communicators as an argument.
procedure
(connect-to-server server [port-number]) → communicator?
server : string? port-number : (integer-in 0 65535) = 119
Connects to server at port-number.
procedure
(disconnect-from-server communicator) → void?
communicator : communicator?
Disconnects an NNTP communicator.
procedure
(open-news-group communicator newsgroup)
→
exact-nonnegative-integer? exact-nonnegative-integer? exact-nonnegative-integer? communicator : communicator? newsgroup : string?
Selects the newsgroup of an NNTP connection. The returned values are
the total number of articles in the group, the first available
article, and the last available article.
procedure
(authenticate-user communicator username password) → void? communicator : communicator? username : string? password : string?
Tries to authenticate a user with the original authinfo command (uses
cleartext). The password argument is ignored if the server
does not ask for it.
procedure
(head-of-message communicator message-index) → (listof string?) communicator : communicator? message-index : exact-nonnegative-integer?
Given a message number, returns its header lines.
procedure
(body-of-message communicator message-index) → (listof string?) communicator : communicator? message-index : exact-nonnegative-integer?
Given a message number, returns the body of the message.
procedure
(newnews-since communicator message-index) → (listof string?)
communicator : communicator? message-index : exact-nonnegative-integer?
Implements the NEWNEWS command (often disabled on servers).
procedure
((generic-message-command command ok-code) communicator message-index) → (listof string?) command : string? ok-code : exact-integer? communicator : communicator? message-index : exact-nonnegative-integer?
Useful primitive for implementing head-of-message,
body-of-message and other similar commands.
procedure
(make-desired-header tag-string) → regexp?
tag-string : string?
Takes a header field’s tag and returns a regexp to match the field
procedure
(extract-desired-headers header desireds) → (listof string?)
header : (listof string?) desireds : (listof regexp?)
Given a list of header lines and of desired regexps, returns the
header lines that match any of the desireds.
16.2 Exceptions
The supertype of all NNTP exceptions.
struct
(struct unexpected-response nntp (code text) #:extra-constructor-name make-unexpected-response) code : exact-integer? text : string?
Raised whenever an unexpected response code is received. The
text field holds the response text sent by the server.
struct
(struct bad-status-line nntp (line) #:extra-constructor-name make-bad-status-line) line : string?
Raised for mal-formed status lines.
struct
(struct premature-close nntp (communicator) #:extra-constructor-name make-premature-close) communicator : communicator?
Raised when a remote server closes its connection unexpectedly.
struct
(struct bad-newsgroup-line nntp (line) #:extra-constructor-name make-bad-newsgroup-line) line : string?
Raised when the newsgroup line is improperly formatted.
struct
(struct non-existent-group nntp (group) #:extra-constructor-name make-non-existent-group) group : string?
Raised when the server does not recognize the name of the requested
group.
struct
(struct article-not-in-group nntp (article) #:extra-constructor-name make-article-not-in-group) article : exact-integer?
Raised when an article is outside the server’s range for that group.
struct
(struct no-group-selected nntp () #:extra-constructor-name make-no-group-selected)
Raised when an article operation is used before a group has been
selected.
struct
(struct article-not-found nntp (article) #:extra-constructor-name make-article-not-found) article : exact-integer?
Raised when the server is unable to locate the article.
struct
(struct authentication-rejected nntp () #:extra-constructor-name make-authentication-rejected)
Raised when the server reject an authentication attempt.
16.3 NNTP Unit
nntp@ and nntp^ are deprecated. They exist for backward-compatibility and will likely be removed in the future. New code should use the net/nntp module.
| (require net/nntp-unit) | package: compatibility-lib |
value
nntp@ : unit?
Imports nothing, exports nntp^.
16.4 NNTP Signature
| (require net/nntp-sig) | package: compatibility-lib |
signature
nntp^ : signature
Includes everything exported by the net/nntp module.