B4J Tutorial [Server] Regex Tool

Online example: http://basic4ppc.com:51042/regex/index.html

This tool allows you to test regular expressions patterns. The handler is quite simple.

Public Sub Handle(req As ServletRequest, resp As ServletResponse)
   Dim jp As JSONParser
   Dim data() As Byte = Bit.InputStreamToBytes(req.InputStream)
   jp.Initialize(BytesToString(data, 0, data.Length, "UTF8"))
   Dim resJson As Map
   resJson.Initialize
   Try
     Dim json As Map = jp.NextObject
     Dim options As Int = 0
     If json.Get("case_sensitive") = False Then options = Regex.CASE_INSENSITIVE
     If json.Get("multiline") = True Then options = Bit.OR(options, Regex.MULTILINE)
     Dim m As Matcher = Regex.Matcher2(json.Get("pattern"), options, json.Get("text"))
     Dim res As StringBuilder
     res.Initialize
     Do While m.Find
       res.Append("Match (length=" & m.Match.Length & "): " & _
         EscapeXml(m.Match)).Append("<br/>")
       For g = 1 To m.GroupCount
         res.Append("Group #" & g & ": " & EscapeXml(m.Group(g))).Append("<br/>")
       Next
     Loop
     If res.Length = 0 Then res.Append("No matches were found.")
     resJson.Put("success", True)
     resJson.Put("log", res.ToString)
   Catch
     resJson.Put("success", False)
     resJson.Put("error", LastException.Message)
   End Try
   
   Dim jg As JSONGenerator
   jg.Initialize(resJson)
   resp.ContentType = "application/json"
   resp.Write(jg.ToString)
End Sub

The request is a JSON object. It holds the pattern, text and two options. The handler parses the given string with the pattern and returns the result as a JSON object.

The handler and static files are attached.

 

[alwaysbusy]

Love this! Also very useful for other programming languages. Thanks

 

[Erel]

An encoding issue was reported: http://www.b4x.com/android/forum/threads/regex-online-tool-problem.39223/

The solution is to set the response encoding:

resp.CharacterEncoding = "UTF8"

 

[Peter Simpson]

Wow this is great, thank you Erel.