Editing Sharepoint Online HTML content using Client Object Model - sharepoint

Question

We have a sharepoint online site with a good amount of pages that have href links to a shared in-house network server. Example: file://servername/sharedFolder This way when the user clicks the href - it directs them to the location in the file explorer if using IE or Edge.
Due to server maintenance - we needed to rename the server. So now "servername" is "servername1". This messes up all the links on the sharepoint site.
I need to iterate over all the pages on the sharepoint site, and fix the hrefs.
I apologize im very new to sharepoint so maybe im missing something very simple.
What i have right now is the following:
using (ClientContext ClientWebContext = new ClientContext("site"))
{
ClientWebContext.Credentials = new SharePointOnlineCredentials("username", ss);
Web web = ClientWebContext.Web;
Microsoft.SharePoint.Client.File file = ClientWebContext.Web.GetFileByServerRelativeUrl("page");
ClientWebContext.Load(web, w => w.Title, w => w.Description, w=> w.Lists);
ClientWebContext.Load(file, f => f.Length, f=> f.ServerRelativeUrl, f=> f.Name, f=>f.);
ClientResult<System.IO.Stream> str = file.OpenBinaryStream();
ClientWebContext.ExecuteQuery();
FileInformation fileInfo = Microsoft.SharePoint.Client.File.OpenBinaryDirect(ClientWebContext, file.ServerRelativeUrl);using (FileStream filestream = new FileStream("C:" + "\\" + file.Name, FileMode.Create))
{
fileInfo.Stream.CopyTo(filestream);
}
}
The idea was to download the page - parse the html and update the hrefs, then write the page back out to the sharepoint server. But when i view the file that has been downloaded it doesnt contain any of the html that is actually on the page.
If i go to a page, select "edit", then select "Edit Source" I can view and edit all the html in raw format.
I guess the question is - how do i get this html and how do i pro grammatically update it.
EDIT:
A typical sharepoint page contains a table, cells & text inside of those cells. The text then contains links to the server I was talking about above. The sharepoint site is essentially being used as a wiki for new employees and a resource for existing employees to find information quickly. It doesnt contain many complex web parts and embedded code, mainly just a table, cells and text.
Thanks,
-John

Answer 1

Yeah, I don't think this approach will fly.
Again, different types of SharePoint pages have different web parts. Modern SharePoint site page, Wiki page, web part page. They all can have text web parts and/or page elements that can hold HTML, and in some, the WYSIWYG default presentation can be changed to a HTML editor. Then there are also list web parts, link web parts, and all kinds of stuff that can have an underlying link URL.
But these page elements are SharePoint artifacts. The page elements and their contents are stored in an internal SharePoint database. The page chrome and styling is also stored in different parts of the database. The SharePoint server processes the different parts that make up a page. On the SharePoint server side, these page elements then get translated and rendered into HTML that is served to the end user's browser.
You cannot take this rendered end result and expect to use it to change the underlying source of the HTML.
You need to get to the source. Again, what exactly that source is depends on the type of page used. Just because it is "in SharePoint" doesn't identify the page type.
Sorry, I know this is not what you want to hear, but if you want to manipulate SharePoint content, you need to acquire an understanding of what SharePoint is and what its moving parts are.