Failed to create folder through Sharepoint API

Question

Request information：
{
"__metadata": {
"type": "SP.Folder"
},
"ServerRelativeUrl": "/PODEV/SAP%20Library/test"
}

Response information：
{
"error": {
"code": "-1, Microsoft.SharePoint.Client.InvalidClientQueryException",
"message": {
"lang": "en-US",
"value": "The property '__metadata' does not exist on type 'SP.Folder'. Make sure to only use property names that are defined by the type."
}
}
}

Answer 1

I solved the problem.
The problem with the content-type parameter is in the official documentation

Send the request based on the above example

The server will report an error

Then I refer to your answer and change the content-type parameter to: application/json; odata=verbose

The folder is created successfully

Answer 2

Hi @Andy Cen (IVC) ,
Per my test the "ServerRelativeUrl" should be SAP%20Library/test. There might be something wrong in your request header. Please refer to the following sample to create the folder

POST https://{site_url}/_api/web/folders  
Authorization: "Bearer " + accessToken  
Accept: "application/json;odata=verbose"  
Content-Type: "application/json"  
Content-Length: {length of request body as integer}  
X-RequestDigest: "{form_digest_value}"  
  
{  
  "__metadata": {  
    "type": "SP.Folder"  
  },  
  "ServerRelativeUrl": "document library/folder name"  
}  

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Answer 3

Hi @Andy Cen (IVC) ,
Could you provide us the Request Header? One case when this error often happens is when you set ContentType request header as "application/json" instead of "application/json;odata=verbose". I have tested my code and it works. Please take a reference:

		function createFolder() {  
			var folderName = "test99";  
			var fullUrl = _spPageContextInfo.webAbsoluteUrl + "/_api/web/folders";  
			$.ajax({  
				url: fullUrl,  
				type: "POST",  
				data: JSON.stringify({  
					"__metadata": {  
						"type": "SP.Folder"  
					},  
					"ServerRelativeUrl": "Document Lib/" + folderName  
				}),  
				headers: {  
					"accept": "application/json;odata=verbose",  
					"content-type": "application/json;odata=verbose",  
					"X-RequestDigest": $("#__REQUESTDIGEST").val()  
				},  
				success: onQuerySucceeded,  
				error: onQueryFailed  
			});  
		}