Manually constructing a message inside orchestration

Question

Here' the situation. I have a sequence of 12 integration tasks to be run every 15 minutes, most of them actually reading something from the oracle server and pushing it into a web service. I have created a port for both oracle and web service and I created a main orchestration which loops every 15 minutes and calls other orchestrations that will do their tasks.

Now, my problem is that those orchestrations are not invoked by a message arrival, and I have a need to construct a message that I will send to the oracle port. The one that will look like this:

<Select xmlns="http://Microsoft.LobServices.OracleDB/2007/03/HR/Table/EMPLOYEES">
    <COLUMN_NAMES>*</COLUMN_NAMES>
    <FILTER>DATE=somedate</FILTER>
</Select>

I know what the node values will be but I do not know how to construct the message other than to use "magic strings" and concatenating strings that I will load into xmlDoc using LoadXml and then assigning that to message parameters which I would very much like to avoid for a lot of reasons (starting with a change in namespace in the future). Is there a way for orchestration to create the "blank" message which I will then fill in?

Maybe the question is very simple and I can't see the tree from the forest, but all the samples I saw on the net are simplified (meaning someone just drops a ready xml in a watched folder to invoke orchestration) and do not help me.

Answer 1

Create a static helper function that returns a type of XmlDocument. Call this function from within your assign shape.

Inside the helper function you could load settings (namespace etc, or even the full message) from a config or text file.

For best practise you should store this config in SSO. If you need help with this let me know.

Answer 2

Here's a solution I implemented for a similar problem: As Hugh suggests I use a helper inheriting from XmlDocument.

The Xml Template class

using System;
using System.Globalization;
using System.IO;
using System.Reflection;
using System.Xml;

namespace Acme
{
    [Serializable]
    public class ResourceXmlDocument : XmlDocument
    {
        public ResourceXmlDocument(Type assemblyType, string resourceName, QueryValues queryValues)
        {
            try
            {
                Assembly callingAssembly = Assembly.GetAssembly(assemblyType);

                if (null == callingAssembly)
                {
                    throw new ResourceException("GetExecutingAssembly returned null");
                }

                Stream resourceStream = callingAssembly.GetManifestResourceStream(resourceName);

                Load(resourceStream);

                if (null == queryValues)
                {
                    throw new ResourceException("queryValues not initialized");
                }

                if (queryValues.Keys.Count < 1)
                {
                    throw new ResourceException("queryValues.Keys must have at least one value");
                }


                foreach (string querycondition in queryValues.Keys)
                {
                    XmlNode conditionNode = this.SelectSingleNode(querycondition);

                    if (null == conditionNode)
                    {
                        throw new ResourceException(string.Format(CultureInfo.InvariantCulture, "Condition: '{0}' did not return a XmlNode", querycondition));
                    }

                    XmlAttribute valueAttribute = conditionNode.Attributes["value"];

                    if (null == valueAttribute)
                    {
                        throw new ResourceException(string.Format(CultureInfo.InvariantCulture, "Condition: '{0}' with attribute 'value' did not return an XmlAttribute ", querycondition));
                    }

                    valueAttribute.Value = queryValues[querycondition];
                }
            }
            catch (Exception ex)
            {
                throw new ResourceException(ex.Message);
            }
        }
    }
}

Of course my expample targets a fixed attribute value to be set so you'll have to adapt this to your needs.

The QueryValues helper class

using System;
using System.Collections.Generic;
using System.Runtime.Serialization;

namespace Acme
{
    [Serializable]
    public class QueryValues : Dictionary<string, string>
    {
        public QueryValues()
        {
        }


        protected QueryValues(SerializationInfo info, StreamingContext context) : base(info, context)
        {
        }
    }
}

The Xml Template

Add a Xml doc MyTemplate.xml to your project and change the compile action to Embedded Resource so ResorceXmlDocument can load it via Reflection.

<?xml version="1.0" encoding="utf-8" ?>
<root>
    <SomeOtherNode>some (fixed) value</SomeOtherNode>
    <MyNodeName tablename="MyTableName" fieldname="MyFieldName" value="0" />
    <YetAnotherNode>
        <SubNode>Foo</SubNode>
    </YetAnotherNode>
</root>

Orchestration variables and Messages

You'll need to declare

• a variable *queryValues* of type `Acme.QueryValues`
• a variable *resourceXmlDoc* of type `Acme.ResourceXmlDocument`
• a message of type `MySchemaType`

Putting it together inside a Message Assignment Shape

inside a Construct Message Shape creating a Message MyRequest of type MySchemaType

queryValues = new Acme.QueryValues();

queryValues.Add("//MyNodeName[@tablename='MyTableName' and @fieldname='MyFieldName']", "MyValueToSet");

resourceXmlDoc = new Acme.ResourceXmlDocument(typeof(Acme.MySchemaType), "MyTemplate.xml", queryValues);

MyRequest = resourceXmlDoc;

I'm keeping ResourceXmlDocument and QueryValues in a util lib and reference it from any BizTalk project I need. The various Xml template docs are embedded into the respective BizTalk assembly.

EDIT by OP: Actually the only way I go this to work is to also implement ISerializable on ResourceXmlDocument and persist message using custom serialization of OuterXml. The XmlDocument in the base is simply not serializable on its own. If there is another approach, feel free to edit this.

[Serializable]
public class ResourceXmlDocument : XmlDocument, ISerializable
{

    ...

    protected ResourceXmlDocument(SerializationInfo info, StreamingContext context)
    {
        if (info == null) throw new System.ArgumentNullException("info");
        Load(info.GetString("content"));
    }


    void ISerializable.GetObjectData(SerializationInfo info, StreamingContext context)
    {
        if (info == null) throw new System.ArgumentNullException("info");
        info.AddValue("content", this.OuterXml);
    }

Answer 3

Yossi Dahan compares these methods (map, assign, and using an undocumented API) here

The API method uses Microsoft.BizTalk.Component.Interop.DocumentSpec - references here and here, but as Yossi mentions, is much slower than maps or XmlDocument.LoadXml

Just some notes on the usage:

• Assembly is TestSchema, Version=1.0.0.0, Culture=neutral, publicKeyToken=xxxxxxxxxxxxxxxx”;
• schemaName is TestSchema.MyTestSchema[+myRootNode1]
• Note is Version dependent - is that if the Assembly Version changes, then creation will fail unless also update version string.
• The new Message Created in this way isn't necessarily valid against the XSD. e.g. DateTimes and Ints will just be empty elements, even if they are nillable (and this won't set the nillable=true in the XML)

Answer 4

Have you considered using a transform shape to create an instance of the schema you want to send on to ORACLE?

That's one alternative to creating the message in the Message Assignment shape. Let me know if you require more detail!

HTH