Batch update task field In SharePoint Project server 2013 using CSOM

Question

I'm trying to update fields of a Project server task ("name" for example). My query works fine if I run it as is without batch (I get empty response from server, but the field value changes), but when I add it into a batch it does nothing also returning empty response.

Could you, please, help me to find out what's wrong with my query?

Request without batch that works:

PATCH /pwa/_api/ProjectServer/Projects/GetById('0e3e5db7-ecf2-eb11-911f-001dd8b71c8d')/Draft/Tasks/GetById('005056b6-19d5-1edb-bcdd-9945eea08d54') HTTP/1.1
    Host: <host>
    Accept: application/json
    X-RequestDigest: 0x9CE4CFDF2C5F6E3264993EEBA7C2D5DE1CA4D9E0B0DF175735D6B098E7DEFD04DD0C59F69C28DF7C5EF25A5928D2921F67910279CEEB20DEF18497603F1273A4,12 Aug 2021 09:04:00 -0000
    Content-Type: application/json
    Authorization: Basic cG93ZXJtXHNhcF9jb25uZWN0OlR5aGc4NHVpcA==
    Content-Length: 144
    
    {"odata.metadata":"http://<host>/sites/PWA/_api/$metadata#SP.ApiData.DraftProjects/@Element","odata.type":"PS.DraftTask","Name":"new_name"}

Request in batch that doesn't:

POST /pwa/_api/$batch HTTP/1.1
Host: <host>
X-RequestDigest: 0x9CE4CFDF2C5F6E3264993EEBA7C2D5DE1CA4D9E0B0DF175735D6B098E7DEFD04DD0C59F69C28DF7C5EF25A5928D2921F67910279CEEB20DEF18497603F1273A4,12 Aug 2021 09:04:00 -0000
Content-Type: multipart/mixed; boundary=batch_e3b6819b-13c3-43bb-85b2-24b14122fed1
Authorization: Basic cG93ZXJtXHNhcF9jb25uZWN0OlR5aGc4NHVpcA==
Content-Length: 796

--batch_45473b4e-5ce5-409d-dd5a-3d60082df906
Content-Type: multipart/mixed; boundary="changeset_f9c96a07-641a-4897-90ed-d285d2dbfc2e"
Content-Length: 563
Content-Transfer-Encoding: binary

--changeset_f9c96a07-641a-4897-90ed-d285d2dbfc2e
Content-Type: application/http
Content-Transfer-Encoding: binary

PATCH http://<host>/pwa/_api/ProjectServer/Projects/GetById('0e3e5db7-ecf2-eb11-911f-001dd8b71c8d')/Draft/Tasks/GetById('005056b6-19d5-1edb-bcdd-9945eea08d54') HTTP/1.1
Content-Type: application/json;odata=verbose

{"odata.metadata":"http://<host>/sites/PWA/_api/$metadata#SP.ApiData.DraftProjects/@Element","odata.type":"PS.DraftTask","Name":"new_name"}

--changeset_f9c96a07-641a-4897-90ed-d285d2dbfc2e--

--batch_45473b4e-5ce5-409d-dd5a-3d60082df906--

response:

--batchresponse_708f48ce-0d0a-4097-8bac-607f4c89db0e--

Answer 1

I've figured it out. The issue was that the biundary in my request differs from the batch number. Still doesn't work though, but now I get response:

--batchresponse_a97eef74-38b3-4c1d-b082-2ac1040e7aac
Content-Type: application/http
Content-Transfer-Encoding: binary

HTTP/1.1 400 Bad Request
CONTENT-TYPE: application/xml;charset=utf-8

<?xml version="1.0" encoding="utf-8"?><m:error xmlns:m="http://schemas.microsoft.com/ado/2007/08/dataservices/metadata"><m:code>-1, Microsoft.SharePoint.Client.InvalidClientQueryException</m:code><m:message xml:lang="en-US">Invalid request.</m:message></m:error>
--batchresponse_a97eef74-38b3-4c1d-b082-2ac1040e7aac--