"Illegal or missing hexadecimal sequence in chunked-encoding" in some scenarios

[forums]

When connecting to the new environment we receive an error on the request for OData4-metadata (.../odata4) when taken from OData response cache.

For example, using curl the error is:

curl: (56) Illegal or missing hexadecimal sequence in chunked-encoding

Using Postman, the error is:

Parse Error: Invalid character in chunk size

On Power BI, the error is:

OData: We were unable to detect required payload information.

The same URL works fine using Google Chrome, FireFox and Edge.

Please note that the initial download is always succesfull.

[forums]

It seems to be isolated to the following conditions:

• Request is using HTTP/1.1 with chunking (so does not appear on HTTP2 since HTTP2 has no longer chunking as in HTTP1.1)
• Request is done to the Linux-based environment (not to the Windows-based environments)
• Only occurs when data is retrieved from the OData response cache. With OData response cache disabled, the error never appears.

The following C# code returns a different error depending on whether using .net 6 or .net7 or newer.

Code:

using (HttpClient client = new HttpClient())
            {
                string url = "https://bridge-online.cloud/xxx/odata4";
                string username = "xxx";
                string password = "xxx";

                client.DefaultRequestHeaders.Authorization = new AuthenticationHeaderValue("Basic", Convert.ToBase64String(Encoding.ASCII.GetBytes($"{username}:{password}")));

                HttpRequestMessage request = new HttpRequestMessage(HttpMethod.Get, url);

                HttpResponseMessage response = await client.SendAsync(request);

                response.EnsureSuccessStatusCode();
            }

On .net 6, the error is:

The HTTP response headers length exceeded the set limit of 65536 bytes.

On .net 7 and 8, the error is:

The HTTP/1.1 response chunk was too large.

It however succeeds when you add before the line with await the following statement:

request.Version = new Version(2, 0);

[forums]

The source of this problem has been determined to differences in handling of the Transfer-Encoding HTTP header between Microsoft IIS and Kestrel. Changes have been applied to the Linux-variants to leave out the Transfer-Encoding where necessary.