How to get the stream for a template on a Document Library

I am trying to load the template file my SPDocumentLibrary has set, do some transforms in OpenXML then save it back to the library as a document. I think I have all the steps down except reading the template. I don't know the "correct" way to open it (I could just use a WebClient to download it but it makes me feel dirty just typing that). Here is what I have so far.

public string GetOrGenerateChecklist(string PracticeName, string ContractID, string EducationDate, string MainContactInfo, string Address)
{
    using (SPWeb web = SPContext.Current.Web)
    {
        SPDocumentLibrary list = (SPDocumentLibrary)web.Lists["Educator Checklists"];
        var templetAddr = String.Concat(web.Url, '/', list.DocumentTemplateUrl);
        SPQuery query = new SPQuery();
        query.Query = string.Concat(
                                //Snip
                                   );
        var items = list.GetItems(query);
        //if document exists return existing document.
        if (items.Count > 0)
            return String.Concat(web.Url, "/Educator Checklists/", PracticeName, " - ", ContractID, ".docx");

        MemoryStream documentStream;

        //copy the stream to memory
        using (Stream tplStream = ????????) //<-------   my problem
        {
            documentStream = new MemoryStream((int)tplStream.Length);
            CopyStream(tplStream, documentStream);
            documentStream.Position = 0L;
        }
        using (WordprocessingDocument template = WordprocessingDocument.Open(documentStream, true))
        {
            template.ChangeDo开发者_开发知识库cumentType(DocumentFormat.OpenXml.WordprocessingDocumentType.Document);
            MainDocumentPart mainPart = template.MainDocumentPart;
            mainPart.DocumentSettingsPart.AddExternalRelationship(
                "http://schemas.openxmlformats.org/officeDocument/2006/relationships/attachedTemplate",
                new Uri(templetAddr, UriKind.Absolute));

            ReplaceText(mainPart, "#PracticeName#", PracticeName);
            ReplaceText(mainPart, "#EducationDate#", EducationDate);
            ReplaceText(mainPart, "#MainContactInfo#", MainContactInfo);
            ReplaceText(mainPart, "#Address#", Address);
        }
        documentStream.Position = 0L;
        list.RootFolder.Files.Add(String.Concat(PracticeName, " - ", ContractID, ".docx"), documentStream);

        return String.Concat(web.Url, "/Educator Checklists/", PracticeName, " - ", ContractID, ".docx");
    }

}

So my question is how do i get the template stored at templetAddr loaded in to the memory stream?

Also I am fairly new to sharepoint so if you see any other big mistakes I have made please let me know.

web.GetFile(templetAddr).OpenBinaryStream() 

http://msdn.microsoft.com/en-us/library/ms476063.aspx (SPWeb.GetFile)

http://msdn.microsoft.com/en-us/library/ms470901.aspx (SPFile.OpenBinaryStream)

Here is a blog post that discusses some considerations when using the SharePoint object model to get an Open XML document, modify it, and put it back.

http://blogs.msdn.com/b/ericwhite/archive/2010/03/24/modifying-an-open-xml-document-in-a-sharepoint-document-library.aspx

Here is the smallest code to do so:

using System;
using System.Collections.Generic;
using System.IO;
using System.Linq;
using System.Text;
using System.Threading;
using Microsoft.SharePoint;
using DocumentFormat.OpenXml.Packaging;
using DocumentFormat.OpenXml.Wordprocessing;

class Program
{
    static void Main(string[] args)
    {
        string siteUrl = "http://localhost";
        using (SPSite spSite = new SPSite(siteUrl))
        {
            Console.WriteLine("Querying for Test.docx");
            SPList list = spSite.RootWeb.Lists["Shared Documents"];
            SPQuery query = new SPQuery();
            query.ViewFields = @"<FieldRef Name='FileLeafRef' />";
            query.Query =
              @"<Where>
                  <Eq>
                    <FieldRef Name='FileLeafRef' />
                    <Value Type='Text'>Test.docx</Value>
                  </Eq>
                </Where>";
            SPListItemCollection collection = list.GetItems(query);
            if (collection.Count != 1)
            {
                Console.WriteLine("Test.docx not found");
                Environment.Exit(0);
            }
            Console.WriteLine("Opening");
            SPFile file = collection[0].File;
            byte[] byteArray = file.OpenBinary();
            using (MemoryStream memStr = new MemoryStream())
            {
                memStr.Write(byteArray, 0, byteArray.Length);
                using (WordprocessingDocument wordDoc =
                    WordprocessingDocument.Open(memStr, true))
                {
                    Document document = wordDoc.MainDocumentPart.Document;
                    Paragraph firstParagraph = document.Body.Elements<Paragraph>()
                        .FirstOrDefault();
                    if (firstParagraph != null)
                    {
                        Paragraph testParagraph = new Paragraph(
                            new Run(
                                new Text("Test")));
                        firstParagraph.Parent.InsertBefore(testParagraph,
                            firstParagraph);
                    }
                }
                Console.WriteLine("Saving");
                string linkFileName = file.Item["LinkFilename"] as string;
                file.ParentFolder.Files.Add(linkFileName, memStr, true);
            }
        }
    }
}