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rss

Description

An RSS parser

Author

felix winkelmann

Requirements

ssax

Documentation

A basic RSS parser, supporting 0.92, 1.0 and 2.0 formats.

All errors signalled by the feed reader are composite conditions of the exn and rss kinds.

[procedure] (rss:read [PORT])

Reads an RSS feed from the given PORT, or from the value of (current-input-port), if no port is specified. A rss:feed record is returned.

[record] rss:feed
[procedure] (rss:feed? x)
[procedure] (rss:feed-version FEED)
[procedure] (rss:feed-channel FEED)
[procedure] (rss:feed-items FEED)
[procedure] (rss:feed-base-uri FEED)

A record that holds information for an RSS feed. The version field contains a string, the channel field and the items hold a single rss:item and a list of rss:items, respectively. The base-uri field contains a string pointing to the base uri (if the xml:base attribute is defined in rss tag).

[record] rss:item
[procedure] (rss:item? X)
[procedure] (rss:item-title ITEM)
[procedure] (rss:item-link ITEM)
[procedure] (rss:item-description ITEM)
[procedure] (rss:item-enclosures ITEM)
[procedure] (rss:item-attributes ITEM)

A record containing data of a RSS item. The title, link and description fields are strings. The rss:item-enclosures procedure returns a list of enclosure records (see below). The attributes field holds an association list mapping symbols to strings and contain all sub-elements of a specific RSS item, including the title, link description and enclosure values. So:

 (eq? (alist-ref 'title (rss:item-attributes ITEM)) (rss:item-title ITEM))  ==>  #t

The item attribute is an SXML expression of the form

 (image (title STRING) ...)

where ... hold additional subelements of the image attribute.

[procedure] (rss:item-attribute ITEM SYMBOL)

Returns the attribute SYMBOL of the RSS feed item ITEM or #f if the item does not contain an attribute of this name.

[procedure] (rss:item=? ITEM ITEM)

Returns #t if the items have identical GUID attributes or (if no GUIDs are available) if the items have the same contents.

[record] rss:enclosure

Holds the url of an embedded file, the mime-type of that file and the length in bytes. It's accessors are defined as follows:

[procedure] (rss:renclosure? X)
[procedure] (rss:enclosure-url ENCLOSURE)
[procedure] (rss:enclosure-type ENCLOSURE)
[procedure] (rss:enclosure-length ENCLOSURE)

All the returned values are strings.

Changelog

License

 Copyright (c) 2004-2011, Felix L. Winkelmann
 All rights reserved.
 
 Redistribution and use in source and binary forms, with or without modification, are permitted provided that the following
 conditions are met:
 
   Redistributions of source code must retain the above copyright notice, this list of conditions and the following
     disclaimer. 
   Redistributions in binary form must reproduce the above copyright notice, this list of conditions and the following
     disclaimer in the documentation and/or other materials provided with the distribution. 
   Neither the name of the author nor the names of its contributors may be used to endorse or promote
     products derived from this software without specific prior written permission. 
 
 THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND ANY EXPRESS
 OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY
 AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDERS OR
 CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
 CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
 SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
 THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR
 OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
 POSSIBILITY OF SUCH DAMAGE.