StPendl
Feb 18, 2012
- "syntax highlighting changed to LB"
Welcome to my tiny Rss parser...I'm trying to create a small rss reader in liberty basic...I don't have any scientific background about programming, but little bit of little bit of that, i'm enjoying my time to write small applications in Liberty Basic (or other basics, but i find liberty basic really basic about GUI applications, is it only me?). Well as i'm writing the code, i'm trying to purify it as much as i can...The code i provide here is able strip most rss tags and print to mainwin...I'll change it by time, to get adapted for a GUI, so i need to place parsed elements to some string variable with index...I hope this will work for all...
See the first part for the URL,receive code from Alycesrestaurant.com
Comments, advices, and any help on GUI is welcomed...Probably, i will need to deal with listview's little bit...Actually i have another idea to make the GUI, html based and show it in a lightweight browser...Not sure but again from Alycesrestaurant.com or lbpe.wikispaces.com...I'll find soon...
ozgur(.)erdiller(at)gmail(.)com
See the first part for the URL,receive code from Alycesrestaurant.com
GLOBAL rss$'Updated on 12/12/2009 - Minor Changes
url$="http://rss.cnn.com/rss/cnn_topstories.rss"
localfile$="rss.xml"
a=geturl(url$,localfile$)
a= StripTags(rss$)
Function geturl(url$,localfile$)
uniUrl$ = MultiByteToWideChar$(url$)
if uniUrl$ = "" then
print "Unable to convert URL to unicode string."
end
end if
'if result = 0, URL is valid
result = ValidURL(uniUrl$)
if result = 0 then
'download html from url
Cursor Hourglass
downloadresult = DownloadToFile(url$,localfile$)
if downloadresult <> 0 then print "Error downloading ";url$
Cursor Normal
else
print "Invalid URL:"; url$
end if
'Now opening the rss file, and binding to local var...
'Will be array for future multiple rss...
open localfile$ for input as #f
rss$=input$ (#f, lof(#f))
close #f
End Function
function StripTags(raw$)
'print only the tags starting with < and ending with >
'According to RSS 2.0 standart we have the following channel data..
'First, start with rss or xml declaration, version...Then
'Channel
' |-Title Required
' |-Link Required
' |-Description Required
'
' |-Language Optional
' |-Copyright Optional
' |-managingEditor Optional
' |-webMaster Optional
' |-pubDate Optional
' |-lastBuildDate Optional
' |-category Optional
' |-generator Optional
' |-docs Optional
' |-cloud Optional
' |-ttl Optional
' |-image Optional---------------------------------------------
' |-rating Optional |><url></url>
' |-textInput Optional |<title></title>
' |-skipHours Optional |<link></link>
' |-skipDays Optional |<width></width>
' |<height></height>
' |<description></description>
'
'
'
'
'
'
'
' Elements of items...Items are sub-elements of Channels btw...
'So
'Channel----
' |---<item>
' |---<item>
' |---<item>
' |---<item>
' |-Title
' |-Link
' |-Description
' |-Author
' |-Category
' |-Comments
' |-enclosure
' |-guid
' |-pubDate
' |-source
'But the point is that most rss feeds doesn't follow this sequence of tags...So, first, we'll remove the tags
'with the information attached to them, and we'll have TAG=Content type of arrays...
channeltags$="title,link,description,language,copyright,managingeditor,webmaster,pubdate,lastbuilddate,category,generator,docs,cloud,ttl,image,rating,textinput,skiphours,skipdays,"
itemtags$="title,link,description,author,category,comments,enclosure,guid,pubdate,source,"
imgtags$="url,title,link,width,height,description,"
while tagend<len(raw$)
tagstart=instr(raw$,"<",tagend)
tagend=instr(raw$,">",tagstart)
taglen=tagend-tagstart+1
'print mid$(raw$,leftbrack,taglen), rightbrack
if instr(mid$(raw$,tagstart,taglen),"<channel>",0)>0 then
chcount=1
print "We found a channel! "
while word$(channeltags$,chcount,",")<>""
'if instr(raw$,"<"+word$(channeltags$,chcount,",")+">")<>0 then
tagstart=instr(raw$,"<"+word$(channeltags$,chcount,",")+">")+len("<"+word$(channeltags$,chcount,",")+">")
tagend=instr(raw$,"</"+word$(channeltags$,chcount,",")+">",tagstart)
taglen=tagend-tagstart
if word$(channeltags$,chcount,",")="image" then 'Parsing image...
itcount=1
imgraw$=mid$(raw$,tagstart,taglen)
while word$(imgtags$,itcount,",")<>""
imgstart=instr(imgraw$,"<"+word$(imgtags$,itcount,",")+">")+len("<"+word$(imgtags$,itcount,",")+">")
imgend=instr(imgraw$,"</"+word$(imgtags$,itcount,",")+">",imgstart)
imglen=imgend-imgstart
print "Channel>Image>";word$(imgtags$,itcount,",");">";mid$(imgraw$,imgstart,imglen)
itcount=itcount+1
wend
goto [skipimage]
end if
print upper$(word$(channeltags$,chcount,","));">>>>";mid$(raw$,tagstart,taglen)
'here, if we have image, seperately we must parse it...
[skipimage]
'end if
chcount=chcount+1
wend
'Upto here, everything is working fine...Missing parts are GUID and media...image tag should be parsed independent...
filepos=instr(raw$,"<item>")
while instr(raw$,"<item>")<>0'Loop until there are no items left...
'since channel is finished, cut the raw$ to only size of items...
currentitem$=mid$(raw$,filepos-1,instr(raw$,"</item>"))
raw$=right$(raw$,len(raw$)-instr(raw$,"/item>"))
itemcount=1
print "New item!":print:print
while word$(itemtags$,itemcount,",")<>""
if instr(lower$(currentitem$),"<"+word$(itemtags$,itemcount,",")+">")<>0 then
tagstart=instr(lower$(currentitem$),"<"+word$(itemtags$,itemcount,",")+">")+len("<"+word$(itemtags$,itemcount,",")+">")
tagend=instr(lower$(currentitem$),"</"+word$(itemtags$,itemcount,",")+">",tagstart)
taglen=tagend-tagstart
print upper$(word$(itemtags$,itemcount,","));">>>>";mid$(currentitem$,tagstart,taglen)
' print tagstart,tagend,taglen
end if
itemcount=itemcount+1
filepos=1
wend'single item
wend'whole items...
end if 'channel end if...
wend
'Upto here, everything is working fine...Missing parts are GUID and media
End Function
Function Window(sizex,sizey,posx,posy)
End Function
Function lowercase (string$)
lowercase$=lower$(string$)
End Function
Function DownloadToFile(urlfile$, localfile$)
open "URLmon" for dll as #url
calldll #url, "URLDownloadToFileA",_
0 as long,_ 'null
urlfile$ as ptr,_ 'url to download
localfile$ as ptr,_ 'save file name
0 as long,_ 'reserved, must be 0
0 as long,_ 'callback address, can be 0
DownloadToFile as ulong '0=success
close #url
end function
Function ValidURL(urlfile$)
open "URLmon" for dll as #url
calldll #url, "IsValidURL",_
0 as long,_ 'ignored, must be 0
urlfile$ as ptr,_ 'urlfile to check
0 as ulong,_ 'ignored, must be 0
ValidURL as long
close #url
end function
function MultiByteToWideChar$(String$)
'converts any string into unicode
CodePage = 0 : dwFlags = 0
cchMultiByte = -1
lpMultiByteStr$ = String$
cchWideChar = len(String$) * 3
lpWideCharStr$ = space$(cchWideChar)
calldll #kernel32, "MultiByteToWideChar", _
CodePage as ulong, _ 'CP_ACP=0, ansi code page
dwFlags as ulong, _ 'use 0, flags for character translation
lpMultiByteStr$ as ptr,_'the ascii string to convert
cchMultiByte as long, _ 'len of string, -1 for null-terminated string
lpWideCharStr$ as ptr, _'buffer for returned ansi string
cchWideChar as long, _ 'size in wide characters of string buffer
result as long 'returns number of wide characters written to buffer
if result = 0 then
MultiByteToWideChar$ = ""
else
MultiByteToWideChar$ = left$(lpWideCharStr$, result * 2)
end if
end function
Comments, advices, and any help on GUI is welcomed...Probably, i will need to deal with listview's little bit...Actually i have another idea to make the GUI, html based and show it in a lightweight browser...Not sure but again from Alycesrestaurant.com or lbpe.wikispaces.com...I'll find soon...
ozgur(.)erdiller(at)gmail(.)com