Mega Code Archive
Easy Parsing an XML File
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Title: Easy Parsing an XML File
Question: In modern times, a configuration file has to be an XML standard so you want to parse that file to get the elements from corresponding nodes.
Answer:
First you have to import the Type library. This will create a wrapper class for that component and all you have to do is to name it in uses in your unit.
I used msxml.dll(Version 2.0) to install the XML parsing components in the IDE through the Import Type Library option.
See for more details:
Importing XML DOM Parser in Delphi /ID 2021
Second we produce a simple XML file like a configuration file:
(Name the file myconfig.xml)
(Strange things happen (cause the xml interpreter in d3k-editor) with a well-formed file after submit the article, so I had to cancel first tags between databases and databases )
please download the file: http://max.kleiner.com/myconfig.xml
******************************************************************************
?xml version="1.0"?
{databases
database db="InterBase"
connection
nameTrueSoft
pathsuperPath
userMaxMin
/connection
/database
database db="myMax"
connection
namemaXml
serverkylix02
usercarpeDiem
/connection
/database
/databases}
*****************************************************************************
Third we build the procedure that parses 3 elements and assign it to strings:
myname, mypath, myuser: string[255];
The accID and idNr are just to make the procedure more flexible for permissions and node navigation. The whole procedure goes like this:
1. Find the file myconfig.xml
2. Create the interface pointer xmlDoc
3. Load the XML file
4. Check the error handling with xmlDoc.parseError
5. Select the node
6. Check if it has childs
7. Get the nodelist and assign the elements to strings
*****************************************************************************
procedure TForm1.parseXML;
var
SRec1: TSearchRec;
accID: boolean;
idNr: byte;
myXMLpath: string;
xmlDoc: IXMLDomDocument2;
xmlnode: IXMLDomNode;
xmlnodelist: IXMLDomNodeList;
myname, mypath, myuser: string[255];
begin
accID:= true;
idNr:= 1;
myXMLpath:= extractFilePath(Application.ExeName);
if FindFirst (myXMLpath+'myconfig.xml',faAnyFile,SRec1)=0 then begin
xmlDoc:= CoDomDocument30.Create;
xmlDoc.validateOnParse := True;
xmlDoc.async := False;
xmlDoc.load(myXMLpath+'myconfig.xml');
if xmlDoc.parseError.errorCode = 0 then begin
if accID then begin
xmlDoc.setProperty('SelectionLanguage','XPath');
xmlnode := xmlDoc.selectSingleNode('//databases/database
[@db='+''''+'InterBase'+''''+ ']');
if xmlnode.hasChildNodes then begin
if (idNR 0) then begin
xmlnodelist := xmlnode.childNodes.item[(idNR-1)].selectNodes
('name');
if xmlnodelist.length 0 then
myname:=xmlnode.childNodes.item[(idNR-1)].selectNodes('name').item
[0].text;
xmlnodelist := xmlnode.childNodes.item[(idNR-1)].selectNodes
('path');
if xmlnodelist.length 0 then
mypath:=xmlnode.childNodes.item[(idNR-1)].selectNodes('path').item
[0].text;
xmlnodelist := xmlnode.childNodes.item[(idNR-1)].selectNodes
('user');
if xmlnodelist.length 0 then
myuser:=xmlnode.childNodes.item[(idNR-1)].selectNodes('user').item
[0].text;
end;
end else
showmessage('no XML Childs');
end else
showmessage('no permission');
end else begin
showmessage('load XML error');
xmlDoc := NIL;
FindClose(SRec1)
end;
end else
showmessage('no XML file');
end;
Carpe Diem...
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