How to replace an existing file in SharePoint Online using REST API

Question

I am trying to upload a file using REST API as below:

String.format("{0}/_api/web/getfolderbyserverrelativeurl('{1}')/files" +"/add(overwrite=true, url='{2}')",serverUrl, serverRelativeUrlToFolder, fileName);

But if a file already exists, it doe not replace the existing file, instead throws error "A file with an equivalent name exists."

Please advice me how to proceed with replacing the file.

Answer 1

I think you are using the code in this article to upload a file: https://docs.microsoft.com/en-us/sharepoint/dev/sp-add-ins/upload-a-file-by-using-the-rest-api-and-jquery

In fact, the code will upload the file then change the file name after uploading. When uploading, it will replace the exisiting file if a file already exists.

However,if you try to change the name of the file with existing files'. You will get this error.

For example:

I have a file with name aa.xlsx in the library:

I upload a file test.xlsx and try to rename it with aa.xlsx. I would get this error.

Infact, the file test.xlsx is uploaded successfully, but we cannot changed it name with aa.xlsx.

As a workaround, you could rename the file (test.xlsx) in the local machine (aa.xlsx). Then upload it. Just do not enter the name for the file.

It replaced the existing aa.xlsx.

Answer 2

I have found the same problem with Inuktituk (Unified Canadian Aboriginal Syllabics Unicode block) even though the two files have different names with different lengths and different number of characters. Adding some ascii character to the beginning or end of the file name resolves it.