Updating content types using SharePoint Web Services (SPServices)

When you deploy an updated content type which is created from code and have new fields, your changes won’t automatically be pushed to children that inherit from your content type. This is only the case when you have created your content type using code. In the sandbox solution, I’m using the SharePoint Web Services to add new fields to content types that inherit from the updated content type.

Why the web services? With the push from Microsoft to go more and more client side, I found it a challenge to not do something with simply a farm solution or a server-side script. During the development of the web part, I’ve found 2 annoyances by using the SPServices library and jQuery/SharePoint:

  1. SPServices says every method name is unique. This is not true. There’s a method “UpdateContentType” for both the Lists.asmx and the Webs.asmx. Due to this overlooked bug, the call will always be directed to the Webs.asmx web service. I’ve modified the SPServices js file to comment out the WSops.UpdateContentType method for Webs.
  2. jQuery will always put your generated attributes to lower case. The web services are case-sensitive as you can see from the following screenshot (taken from STSSOAP.DLL, decompiled with ILSpy)
    caseSensitive

The web part itself is pretty straight forward. You’ll get a list of content types with update links.

content type updater webpart

When using firebug or another web dev tool, you can track all the calls that are made to the Webs.asmx & Lists.asmx

content type updater console window

I’ve deployed a custom content type to my site, created a list with that content type and then made an update to the site content type. As you can see there’s a column missing from the list content type:

site content type

list content type

After I click on “Update” next to “CustomContentType”, the script will detect a difference between these two and update accordingly:

soap call new fields

And the updated list content type:

updated list content type

All in all I’m pretty happy with the result. You can do a lot with just the web services from SharePoint, but they take some time to get used to. Also the documentation isn’t always great as for instance they mention to use <FieldRefs> while in the source code of the web service itself there’s only a parse of the <Fields> tag.

For the full source, or if you want to download and test the web part itself, you can go to CodePlex.

0x80070057Bad parameter passed to Web Server Extensions

By using the UpdateListItems() method of the web service Lists.asmx, an update of a list item kept on failing with the following error:

0x80070057Bad parameter passed to Web Server Extensions. Check the information you entered and try again.

The XML passed to the web service was built up as followed:

<Method ID='1' Cmd='Update'>
   <Field Name='ID'>1</Field>
   <Field Name='Title'>Update</Field>
</Method>

There was no real reason why the web service should fail updating the item. The update worked fine on other lists. Turned out that after fiddling and testing with the list, the field “ID” was turned into editable mode and showed up as a column when the list settings were checked.

When the XML is passed to the web service, it successfully finds the fields “ID” and “Title”, but both are updatable. There’s no real identification of the item that should be updated.

The solution for the problem described here, is to turn the field “ID” back to read only. This is possible through PowerShell:

$web = Get-SPWeb http://sharepoint
$list = $web.Lists["ListName"]

$list.Fields["ID"].ReadOnly = $true