Domino Data Service - change name of attached file in rich-text-field

I have an annoying problem and I am not sure anyone knows the answer, but asking cost nothing.

I am attaching a PDF-File via a PATCH-Methode to the Server with the Domino-Data-Service Rest-API. The attaching does work properly, but the attachment in the rich-text-field does have a automatically generated name.

My question: How can I change the name of this file by attaching it.

I wrote my code in C#, but I think this is not an programming language depending problem.

My code for attaching the PDF (C#):

HttpClient client = new HttpClient();
client.DefaultRequestHeaders.Authorization = new AuthenticationHeaderValue("Basic", Convert.ToBase64String(ASCIIEncoding.ASCII.GetBytes({username:passwort})));

Byte[] bytes = File.ReadAllBytes(@"H:\jakob.pdf");
String file = Convert.ToBase64String(bytes);

var json = "{" + 
           "\"anmerkung\":{" +
           "\"type\":\"multipart\"," +
           "\"content\":[ {" +
                      "\"contentType\":\"application/pdf\"," +
                      "\"data\":\"" + file + "\"," +
                      "\"contentTransferEncoding\":\"base64\"" +
                                                           "}" +
                                                           "]" +
                          "}" +
           "}";

var data = new StringContent(json, Encoding.UTF8, "application/json");
var url = @"https://{database}/api/data/documents/unid/424CC34CFB0746F6C12585A7003B277B?computewithform=true&form={formname}";

var response = await client.PatchAsync(url, data);

string result = response.Content.ReadAsStringAsync().Result;
Console.WriteLine(result);
client.Dispose();

This works fine but my PDF looks like this:

I want the pdf file to have the name jakob.pdf

So I tried to rebuild the json, in the way the json is build when using a GET-Request to a document with a PDF file in a rich-text-field

My code for attaching the PDF, with the rebuild json(C#):

HttpClient client = new HttpClient();
client.DefaultRequestHeaders.Authorization = new AuthenticationHeaderValue("Basic", Convert.ToBase64String(ASCIIEncoding.ASCII.GetBytes({username:passwort})));

Byte[] bytes = File.ReadAllBytes(@"H:\jakob.pdf");
String file = Convert.ToBase64String(bytes);


var json2 = "{" +
            "\"anmerkung\":{" +
            "\"type\":\"multipart\"," +
            "\"content\":[ {" +
                       "\"contentType\":\"application/pdf; name=\"jakob.pdf\"\","+
                       "\"contentDisposition\":\"inline; filename=\"jakob.pdf\"\","+
                       "\"data\":\"" + file + "\"," +
                       "\"contentTransferEncoding\":\"base64\"" +
                                                            "}" +
                                                            "]" +
                          "}" +
            "}";

var data = new StringContent(json2, Encoding.UTF8, "application/json");
var url = @"https://{database}/api/data/documents/unid/424CC34CFB0746F6C12585A7003B277B?computewithform=true&form={formname}";

var response = await client.PatchAsync(url, data);

string result = response.Content.ReadAsStringAsync().Result;
Console.WriteLine(result);
client.Dispose();

When I' m using this piece of code I always get an error-message:

"code":400,
"text":"Bad Request",
"message":"Fehler beim Parsen der JSON-Inhalte",
"type":"text",
"data":"com.ibm.domino.services.ServiceException: Fehler beim Parsen der JSON-Inhalte\r\n\tat

Regarding to this peice of code I am not even sure, if this code would normally work it was just an idea, that I tried.

I know this is a very complex and difficult problem, but maybe somone knows the answer to this problem or has some idea to fix this problem.

thanks in advance!

The most likely reason for the error response is that, when you set the filename in your JSON, you have created malformed JSON.

To take a single line of your code as an example, this line is malformed JSON because of the quote characters around the filename:

    "\"contentType\":\"application/pdf; name=\"jakob.pdf\"\","+

The line with contentDisposition has the same problem.

I highly recommend using an API designed to turn a structured object into proper serialized JSON, which should make it easy to avoid the problem, but I don't know what is available in C# for this purpose.

The list at the bottom of the following page may help: https://www.json.org/json-en.html