Use Regular Expressions to get hyperlinks in blogs
At Southwest Fox conference I presented a sample calling a VB.NET server to do regular expression matching.
Here’s the sample I used. It gets some HTML from my blog and parses all the hyperlinks (looks for the HREF tags) and puts them into a VFP table:
First create a VB server: A Visual Basic COM object is simple to create, call and debug from Excel
The VFP code gets the blog page as html then passes that html to the VB server, which does the regular expression matching:
LOCAL ox as vbcom.ComClass1
oVB=CREATEOBJECT("VBCom.ComClass1")
LOCAL oHTTP as "winhttp.winhttprequest.5.1"
oHTTP=NEWOBJECT("winhttp.winhttprequest.5.1")
oHTTP.Open("GET","http://blogs.msdn.com/calvin_hsia",.f.)
oHTTP.Send()
cHTML=ohTTP.ResponseText
cXML =oVB.RegEx(chtml)
XMLTOCURSOR(cxml)
BROWSE LAST NOWAIT
Add a method to the VB class (this version works in VS 2003):
Imports System.Text.RegularExpressions
Imports System.Xml
Public Function RegEx(ByVal cHtml As String) As String
Dim cregex As Regex = New Regex("href\s*=\s*(?:""(?<1>[^""]*)""|(?<1>\S+))", _
RegexOptions.IgnoreCase Or RegexOptions.Compiled)
Dim MatchCollection As MatchCollection = cregex.Matches(cHtml)
Dim sb As New System.Text.StringBuilder
Dim xw As XmlTextWriter = New XmlTextWriter(New System.IO.StringWriter(sb))
xw.WriteStartElement("VFPData")
For Each m As Match In MatchCollection
xw.WriteStartElement("Row") ' for each Row
xw.WriteStartElement("RegEx") ' field name
xw.WriteString(m.Value)
xw.WriteEndElement()
xw.WriteEndElement()
Next
xw.WriteEndElement()
Return sb.ToString
Of course, when I did the demo, I used a newer version of VB and I did a SQL Select from the Regular Expression results. I also used XLINQ, the new XML features of LINQ
Dim aList As New List(Of Match)
For Each m In MatchCollection
aList.Add(m)
Next
Dim res = Select p From p In aList Order By p.Tostring()
Dim xmlMain = <VFPData/>
For Each item In res
Dim xRow = <Row/>
xRow.Add(<RegEx><%= item %></RegEx>)
xmlMain.Add(xRow)
Next
Return xmlMain.ToString
