How to read XML file

[LordBigDuck]

Hello, I have gone through the documentation and source code but didn't manage to write running code to read XML file. Could you provide some samples ?

[paillave]

Indeed, I must write documentation about this. I will come to you asap on this.

[paillave]

I gave a sample code in the issue here: #389 (comment)

Less me know if you have more question.

[LordBigDuck]

Thank you for your reply and sample. I have been able to make it work with simple structure. One more question about XmlNodeDefinition. How can I define a Collection ?

If I take back you example but add a collection inside etl1

<root>
    <elt1 v1="qwe">
        <v2>asd</v2>
        <cols>
            <col>
                <item>
                </item>
            </col>
            <col>
                <item>
                </item>
            </col>
         </cols>
    </elt1>
</root>

How should I define this collection is my XmlNodeDefinition ?

[paillave]

Try something like the following (didn't try yet 😸 let me know, I'll work on it asap )
(that's for this kind of problems that Xml extension must be improved :) )

// See https://aka.ms/new-console-template for more information
using System.Text;
using Paillave.Etl.Core;
using Paillave.Etl.XmlFile;
using Paillave.Etl.XmlFile.Core;

var testXmlContent = @"<root>
    <elt1 v1=""qwe"">
        <v2>asd</v2>
        <cols>
            <col>
                <item>hello</item>
            </col>
            <col>
                <item>world</item>
            </col>
         </cols>
    </elt1>
</root>";

var res = await StreamProcessRunner.CreateAndExecuteAsync("dummy", DefineProcess);
Console.WriteLine(res.Failed ? $"fail: {res.ErrorTraceEvent}" : "Success");

void DefineProcess(ISingleStream<string> contextStream)
{
    var xmlNodes = contextStream
        .Select("create in memory file with content for test", _ => FileValue.Create(new MemoryStream(Encoding.UTF8.GetBytes(testXmlContent)), "example.xml", "testContent"))
        .CrossApplyXmlFile("parse xml", new MyXmlFileDefinition());
    var parentStream = xmlNodes.XmlNodeOfType<Elt1Node>("only Etl1").Do("write elt1", i => Console.WriteLine($"Node type 1 : {i.V1} - {i.V2}"));
    var childStream = xmlNodes.XmlNodeOfType<Elt2Node>("only Etl2").Do("write elt2", i => Console.WriteLine($"Node type 2 : {i.V1} - {i.Item}"));
    // you can join both streams using V1 key. Later on, CrossApplyXmlFile will issue a list of parents node in the proper descendence order with the current node.
}

class MyXmlFileDefinition : XmlFileDefinition
{
    public MyXmlFileDefinition()
    {
        this.AddNodeDefinition(XmlNodeDefinition.Create("elt1", "/root/elt1", i => new Elt1Node
        {
            V1 = i.ToXPathQuery<string>("/root/elt1/@v1"),
            V2 = i.ToXPathQuery<string>("/root/elt1/v2"),
        }));
        this.AddNodeDefinition(XmlNodeDefinition.Create("elt2", "/root/elt1/cols/col", i => new Elt1Node
        {
            V1 = i.ToXPathQuery<string>("/root/elt1/@v1"),
            V2 = i.ToXPathQuery<string>("/root/elt1/cols/col/item"),
        }));
    }
}
class Elt1Node
{
    public string V1 { get; set; }
    public string V2 { get; set; }
}
class ColNode
{
    public string V1 { get; set; }
    public string Item { get; set; }
}