XML Support

1 Dot Operator
2 Attribute Operator
3 Examples
- 3.1 Flikr code clip

BrightScript provides XML support with two BrightScript objects and a set of dedicated language features:

roXMLElement: This object provides support for parsing, generating, and containing XML.
roXMLList: This object is used to contain a list of roXMLElement instances.

Dot Operator

The "." Dot Operator has the following features when used with XML objects:

When used with an roXMLElement instance, the "." Dot Operator returns an roXMLList instance of the child tags that match the dot operand. If no tags match the operand, an empty list is returned.
When applied to an roXMLList instance, the "." Dot Operator aggregates the results of performing the above operation on each roXMLElement in the list.
When applied to XML, which is technically case sensitive, the "." Dot Operator is still case insensitive. If you wish to perform a case-sensitive XML operation, use the member functions of the roXMLElement/roXMLList objects.

Attribute Operator

The “@” Attribute Operator can be used with an roXMLElement instance to return a named attribute. Though XML is case sensitive, the Attribute Operator is always case insensitive. If the Attribute Operator is used with an roXMLList instance, it will only return a value if that list contains exactly one element.

Examples

<?xml version="1.0" encoding="utf-8" ?>
<rsp stat="ok">
    <photos page="1" pages="5" perpage="100" total="500">
        <photo id="3131875696" owner="21963906@N06" secret="f248c84625" server="3125"
        farm="4" title="VNY 16R" ispublic="1" isfriend="0" isfamily="0" />
        <photo id="3131137552" owner="8979045@N07" secret="b22cfde7c4" server="3078"
        farm="4" title="hoot" ispublic="1" isfriend="0" isfamily="0" />
        <photo id="3131040291" owner="27651538@N06" secret="ae25ff3942" server="3286"
        farm="4" title="172 • 365 :: Someone once told me..." ispublic="1" isfriend="0"
        />
    </photos>
</rsp>

Given the XML in the above example.xml file, then the following code will return an roXMLList instance with three entries:

rsp=CreateObject("roXMLElement")
rsp.Parse(ReadAsciiFile("example.xml"))
 
? rsp.photos.photo

The following will return an roXMLElement reference to the first photo (id="3131875696"):

? rsp.photos.photo[0]

The following will return an roXMLList reference containing the <photos> tag:

? rsp.photos

The following will return the string “100”:

rsp.photos@perpage

You can use the roXMLElement.GetText() method to return an element’s text: For example, if the variable <booklist> contains the element <book lang=eng>The Dawn of Man</book>, then the following code will print the string “The Dawn of Man”.

Print booklist.book.gettext()

Alternatively, using the Attribute Operator will print the string “eng”.

print booklist.book@lang

Flikr code clip

REM
REM Interestingness
REM pass an (optional) page of value 1 - 5 to get 100 photos
REM starting at 0/100/200/300/400
REM
REM returns a list of "Interestingness" photos with 100 entries
REM


Function GetInterestingnessPhotoList(http as Object, page=1 As Integer) As Object


	print "page=";page


    http.SetUrl("http://api.flickr.com/services/rest/?method=flickr.interestingness.getList&api_key=YOURKEYGOESHERE&page="+mid(stri(page),2))


    xml=http.GetToString()


    rsp=CreateObject("roXMLElement")
    if not rsp.Parse(xml) then stop

       return helperPhotoListFromXML(http, rsp.photos.photo) 'rsp.GetBody().Peek().GetBody())

      
End Function


Function helperPhotoListFromXML(http As Object, xmllist As Object, owner=invalid As dynamic) As Object


    photolist=CreateObject("roList")
    for each photo in xmllist
       photolist.Push(newPhotoFromXML(http, photo, owner))
    end for
    return photolist


End Function


REM
REM newPhotoFromXML
REM
REM    Takes an roXMLElement Object that is an <photo> ... </photo>
REM    Returns an brs object of type Photo
REM       photo.GetTitle()
REM       photo.GetID()
REM       photo.GetURL()
REM       photo.GetOwner()
REM


Function newPhotoFromXML(http As Object, xml As Object, owner As dynamic) As Object
    photo = CreateObject("roAssociativeArray")
    photo.http=http
    photo.xml=xml
    photo.owner=owner
    photo.GetTitle=function():return m.xml@title:end function
    photo.GetID=function():return m.xml@id:end function
    photo.GetOwner=pGetOwner
    photo.GetURL=pGetURL
    return photo
End Function


Function pGetOwner() As String
	if m.owner<>invalid return m.owner
	return m.xml@owner
End Function


Function pGetURL() As String
	a=m.xml.GetAttributes()
	url="http://farm"+a.farm+".static.flickr.com/"+a.server+"/"+a.id+"_"+a.secret+".jpg"
	return url
End Function