Tech in the 603, The Granite State Hacker

WORKAROUND: Misconfigured Windows-Integrated Authentication for Web Services

In trying to drive a process from a SharePoint list, I ran across a problem…

I couldn’t create a web reference in my C# project due to some really weird problem… In the “Add web reference” wizard, I entered my URL, and was surprised by a pop-up titled “Discovery Credential”, asking me for credentials for the site.

Since I was on the local domain and had “owner” permissions to the site, I thought I would just waltz in and get the WSDL.

Ok, so it wants creds… I gave it my own.

Negative…!?!?

After a few attempts and access denied errors, I hit Cancel, and was rewarded by, of all things, the WSDL display… but I still couldn’t add the reference.

After quite a bit of wrestling, it turns out there was an authentication provider configuration problem. The site was configured to use Kerberos authentication, but the active directory configuration was not set up correctly. (I believe it needed someone to use SetSPN to update the Service Principal Name (SPN) for the service.)

One way to resolve the problem was to set the authentication provider to NTLM, but in my case, I didn’t have, (and wasn’t likely to get) that configuration changed in the site (a SharePoint Web Application) I really needed access to.

In order to make it work, I had to initially create my reference to a similar, accessible site.

(e.g. http://host/sites/myaccessiblesite/_vti_bin/lists.asmx )

Then, I had to initialize the service as such, in code:


private void InitWebService()
{
System.Net.AuthenticationManager.Unregister("Basic");

System.Net.AuthenticationManager.Unregister("Kerberos");

//System.Net.AuthenticationManager.Unregister("Ntlm");

System.Net.AuthenticationManager.Unregister("Negotiate");

System.Net.AuthenticationManager.Unregister("Digest");


SmokeTestSite.Lists workingLists = new SmokeTest.SmokeTestSite.Lists();

workingLists.Url = "http://host/sites/mybrokensite/_vti_bin/lists.asmx";

workingLists.UseDefaultCredentials = true;

workingLists.Proxy = null;

lists = workingLists;
}

What this accomplishes is it unregisters all authentication managers in your application domain. (This can only be done once in the same app domain. Attempts to unregister the same manager more than once while the program’s running will throw an exception.)

So by having all the other authentication managers disabled in the client, the server would negotiate and agree on Ntlm authentication, which succeeds.

Tech in the 603, The Granite State Hacker

Anonymous Form Submission to Form Library with InfoPath in MOSS

Here’s a bit of a trick I ran across while helping to develop some MOSS2007 solutions.

I needed to configure InfoPath so that it could submit documents to a site that the submitter would not be able to access. In SharePoint, this is not directly possible.

A common work-around is to set up incoming email for the target list, and submit by email to that. Unfortunately, my client is part-way through a Notes to Exchange migration, so this wasn’t practical in the given time frame.

The solution… create two sites, one that is accessible to the submitter, and the other that is not. On the accessible site, create a new, “hidden” list that the user can submit to. Add an event receiver to that list, such that whenever a new item is added, the item is moved to the real intended target using elevated privileges.

Using VSeWSS extensions, create a List Definition project that has something like this in the ItemEventReciever.cs file:

 

using System;
using System.Security.Permissions;
using System.Runtime.InteropServices;
using Microsoft.SharePoint;
using Microsoft.SharePoint.Security;
using Microsoft.SharePoint.Utilities;
using VSeWSS;

namespace AutoForwardingFormLibrary
{
[CLSCompliant(false)]
[TargetList("38aea319-af78-4489-9059-d124c68bf9fe")]
[Guid("9d0f139b-d9ed-4b6c-b0ba-2353cb3bad85")]
public class AutoForwardingFormLibraryItemEventReceiver : SPItemEventReceiver
{
private SPListItem addedItem = null;

///
/// Initializes a new instance of the Microsoft.SharePoint.SPItemEventReceiver class.
///

public AutoForwardingFormLibraryItemEventReceiver()
{
}

///
/// Asynchronous after event that occurs after a new item has been added to its containing object.
///

///
/// A Microsoft.SharePoint.SPItemEventProperties object that represents properties of the event handler.
///
public override void ItemAdded(SPItemEventProperties properties)
{
addedItem = properties.ListItem;
if (addedItem == null)
{
throw new ArgumentNullException("properties.ListItem");
}
SPSecurity.CodeToRunElevated moveItem = moveItem_Elevated;
SPSecurity.RunWithElevatedPrivileges(moveItem_Elevated);
}

private void moveItem_Elevated()
{
addedItem.CopyTo(SPUrlUtility.CombineUrl("http://targetserver/sites/jimw/docs/formlibrary", addedItem.Name));
addedItem.Delete();
}
}
}


Tech in the 603, The Granite State Hacker

Reading SharePoint Lists into an ADO.Net DataTable

[Feb 18, 2009: I’ve posted an update to show the newer technique suggested below by Kirk Evans, also compensating for some column naming issues.]

The other day, I needed to write some code that processed data from a SharePoint list. The list was hosted on a remote MOSS 2007 server.

Given more time, I’d have gone digging for an ADO.NET adapter, but I found some code that helped. Unfortunately, the code I found didn’t quite seem to work for my needs. Out of the box, the code missed several columns for no apparent reason.

Here’s my tweak to the solution:

(The ListWebService points to a web service like http://SiteHost/SiteParent/Site/_vti_bin/lists.asmx?WSDL )

private data.DataTable GetDataTableFromWSS(string listName)

{

ListWebService.Lists lists = new ListWebService.Lists();

lists.UseDefaultCredentials = true;

lists.Proxy = null;

//you have to pass the List Name here

XmlNode ListCollectionNode = lists.GetListCollection();

XmlElement List = (XmlElement)ListCollectionNode.SelectSingleNode(String.Format(“wss:List[@Title='{0}’]”, listName), NameSpaceMgr);

if (List == null)

{

throw new ArgumentException(String.Format(“The list ‘{0}’ could not be found in the site ‘{1}'”, listName, lists.Url));

}

string TechListName = List.GetAttribute(“Name”);

data.DataTable result = new data.DataTable(“list”);

XmlNode ListInfoNode = lists.GetList(TechListName);

System.Text.StringBuilder fieldRefs = new System.Text.StringBuilder();

System.Collections.Hashtable DisplayNames = new System.Collections.Hashtable();

foreach (XmlElement Field in ListInfoNode.SelectNodes(“wss:Fields/wss:Field”, NameSpaceMgr))

{

string FieldName = Field.GetAttribute(“Name”);

string FieldDisplayName = Field.GetAttribute(“DisplayName”);

if (result.Columns.Contains(FieldDisplayName))

{

FieldDisplayName = FieldDisplayName + ” (“ + FieldName + “)”;

}

result.Columns.Add(FieldDisplayName, TypeFromField(Field));

fieldRefs.AppendFormat(“”, FieldName);

DisplayNames.Add(FieldDisplayName, FieldName);

}

result.Columns.Add(“XmlElement”, typeof(XmlElement));

XmlElement fields = ListInfoNode.OwnerDocument.CreateElement(“ViewFields”);

fields.InnerXml = fieldRefs.ToString();

XmlNode ItemsNode = lists.GetListItems(TechListName, null, null, fields, “10000”, null, null);

// Lookup fields always start with the numeric ID, then ;# and then the string representation.

// We are normally only interested in the name, so we strip the ID.

System.Text.RegularExpressions.Regex CheckLookup = new System.Text.RegularExpressions.Regex(“^\\d+;#”);

foreach (XmlElement Item in ItemsNode.SelectNodes(“rs:data/z:row”, NameSpaceMgr))

{

data.DataRow newRow = result.NewRow();

foreach (data.DataColumn col in result.Columns)

{

if (Item.HasAttribute(“ows_” + (string)DisplayNames[col.ColumnName]))

{

string val = Item.GetAttribute(“ows_” + (string)DisplayNames[col.ColumnName]);

if (CheckLookup.IsMatch((string)val))

{

string valString = val as String;

val = valString.Substring(valString.IndexOf(“#”) + 1);

}

// Assigning a string to a field that expects numbers or

// datetime values will implicitly convert them

newRow[col] = val;

}

}

newRow[“XmlElement”] = Item;

result.Rows.Add(newRow);

}

return result;

}

// The following Function is used to Get Namespaces

private static XmlNamespaceManager _nsmgr;

private static XmlNamespaceManager NameSpaceMgr

{

get

{

if (_nsmgr == null)

{

_nsmgr = new XmlNamespaceManager(new NameTable());

_nsmgr.AddNamespace(“wss”, http://schemas.microsoft.com/sharepoint/soap/”);

_nsmgr.AddNamespace(“s”, “uuid:BDC6E3F0-6DA3-11d1-A2A3-00AA00C14882”);

_nsmgr.AddNamespace(“dt”, “uuid:C2F41010-65B3-11d1-A29F-00AA00C14882”);

_nsmgr.AddNamespace(“rs”, “urn:schemas-microsoft-com:rowset”);

_nsmgr.AddNamespace(“z”, “#RowsetSchema”);

}

return _nsmgr;

}

}

private Type TypeFromField(XmlElement field)

{

switch (field.GetAttribute(“Type”))

{

case “DateTime”:

return typeof(DateTime);

case “Integer”:

return typeof(int);

case “Number”:

return typeof(float);

default:

return typeof(string);

}

}