RSS Reader

[Pawel]

I want to show on visualization some rss feed. Is there some example of this functionality? Or maybe some library which help to work with xml files?

[admin]

You can use LuaSocket to fetch the RSS feed and the parse it using LuaExpat:
http://w3.impa.br/~diego/software/luasoc...ml#request
https://matthewwild.co.uk/projects/luaex...mples.html

[Pawel]

Thanks, i didnt know which module, to handle with xml, you add.

[Pawel]

Can you give me some working example of luaexpat? this, on the web you gave, is very strange and non documented, so understanding is very difficult.

[admin]

Here's an example that will get text from <title> and <description> tags inside of each <item> tag and save them in a table.

Code:

itemtag = false
result = {}

-- callback for tag start
function starttag(parser, tag)
 -- create new storage in result table for each <item> tag
 if tag == 'item' then
   itemtag = true
   table.insert(result, {})
 end

 currtag = tag
end

-- callback for tag end
function endtag(p, tag)
 if tag == 'item' then
   itemtag = false
 end

 currtag = nil
end

-- callback for character data
function cdata(parser, text)
 -- check if parser is inside of <item> and either in <title> or <description>
 if itemtag and currtag then
   if currtag == 'title' then
     result[ #result ].title = text
   elseif currtag == 'description' then
     result[ #result ].description = text
   end
 end
end

-- create parser
lxp = require('lxp')
parser = lxp.new({
 StartElement = starttag,
 EndElement = endtag,
 CharacterData = cdata,
})

-- sample data
data = [[
<?xml version="1.0" encoding="UTF-8" ?>
<rss version="2.0">
<channel>
<title>RSS Title</title>
<description>This is an example of an RSS feed</description>
<link>http://www.example.com/main.html</link>
<lastBuildDate>Mon, 06 Sep 2010 00:01:00 +0000 </lastBuildDate>
<pubDate>Sun, 06 Sep 2009 16:20:00 +0000</pubDate>
<ttl>1800</ttl>

<item>
 <title>Example entry</title>
 <description>Here is some text containing an interesting description.</description>
 <link>http://www.example.com/blog/post/1</link>
 <guid isPermaLink="true">7bd204c6-1655-4c27-aeee-53f933c5395f</guid>
 <pubDate>Sun, 06 Sep 2009 16:20:00 +0000</pubDate>
</item>

<item>
 <title>Another example entry</title>
 <description>Here is some other text containing an interesting description.</description>
 <link>http://www.example.com/blog/post/1</link>
 <guid isPermaLink="true">7bd204c6-1655-4c27-aeee-53f933c5395f</guid>
 <pubDate>Sun, 06 Sep 2009 16:20:00 +0000</pubDate>
</item>
</channel>
</rss>
]]

if parser:parse(data) then
 log(result)
else
 log('parse failed')
end

[Pawel]

The best and the fastest support in KNX world