Update available page layouts of web using CSOM

Question

Is it possible to update the available page layouts of a web using CSOM? In the interface you can change them by going to the site setting and then to page layout and site template settings, but I didn't find an option yet to do it in code.

EDIT

It looks like I'm able to change the pagelayouts by changing the "__PageLayouts" property of the web. The current value looks like this (I manually did the formatting to make it a bit more readable):

<pagelayouts>
  <layout guid="a62d560d-d34d-4154-80b5-7163e91cd62e" url="_catalogs/masterpage/ContactPage.aspx" />
  <layout guid="efc0944d-4992-4c14-a0d4-5c1632bb04b5" url="_catalogs/masterpage/HowDoI.aspx" />
</pagelayouts>

The thing is, I don't got a clue where these guids are coming from and if I'm able to retrieve them using CSOM

Answer 1

Having reflected the assembly that provides the SetAvailablePageLayouts, I can confirm that all it is doing is setting the "__PageLayouts" web property (and pushing this update to child webs). As such using CSOM to set the property should be sufficient. I assume that the GUID is the UniqueId of the page layout in _catalogs/masterpage gallery.

Answer 2

In Microsoft'S API, there is a function called SetAvailablePageLayouts() that let'S you, like it says, set the available page layouts for a PublishingPage object. In C#, the general function definition is

public void SetAvailablePageLayouts(
PageLayout[] pageLayouts,
bool resetAllSubsitesToInherit
)

Just create a new publishing page object by using GetPublishingWeb($your_SPWeb_var), and then call this function, setting the pageLayouts array with the list of layouts you want to allow.

EDIT: Note that this is for the server-side API, which you may not want to use. I will search for a similar use for client-side, and update my answer accordingly. For now, wait for more appropriate answers.