`DataContent` causes `UriFormatException - Invalid URI: The Uri string is too long` in 1.0.0-rc5

[nor0x]

Description

i have this code that is trying to send a history of TextContent and DataContent to an agent.

var contents = new List<AIContent>();
contents.Add(new Microsoft.Extensions.AI.TextContent("Describe the image"));
contents.Add(new DataContent(new ReadOnlyMemory<byte>(someBytes), "image/jpg"));
var history = new List<ChatMessage>();
history.Add(new ChatMessage(ChatRole.User, contents));
var imageCaption = await _agent.RunAsync(history);

With the latest release of Microsoft.Extensions.AI, i am getting the following error:

   System.Exception {System.UriFormatException}
   {"Invalid URI: The Uri string is too long."}

   at System.Uri.CreateThis(String uri, Boolean dontEscape, UriKind uriKind, UriCreationOptions& creationOptions)
   at System.Uri..ctor(String uriString)
   at Microsoft.Extensions.AI.OpenAIResponsesChatClient.<ToOpenAIResponseItems>d__20.MoveNext()
   at Microsoft.Extensions.AI.OpenAIResponsesChatClient.<GetResponseAsync>d__7.MoveNext()
   at Microsoft.Extensions.AI.FunctionInvokingChatClient.<GetResponseAsync>d__38.MoveNext()
   at Microsoft.Agents.AI.ChatClientAgent.<RunCoreAsync>d__27.MoveNext()
   at Microsoft.Agents.AI.ChatClientAgent.<RunCoreAsync>d__27.MoveNext()

Previously i was using 1.0.0-rc2 (10.3.0) which worked fine, but after upgrading to 1.0.0-rc5 (10.4.0), i am getting this error. I have not changed any code other than the version of Microsoft.Extensions.AI.

I think i have narrowed down the issue to this PR #7349 which changed how DataContent is handled:

BEFORE:

case DataContent dataContent when dataContent.HasTopLevelMediaType("image"):
         (parts ??= []).Add(ResponseContentPart.CreateInputImagePart(BinaryData.FromBytes(dataContent.Data), dataContent.MediaType, GetImageDetail(item)));

AFTER:

case DataContent dataContent when dataContent.HasTopLevelMediaType("image"):
         (parts ??= []).Add(ResponseContentPart.CreateInputImagePart(new Uri(dataContent.Uri), GetImageDetail(item)));

I know that with .NET 10 the Uri Lenght limits were removed:
https://learn.microsoft.com/en-us/dotnet/core/compatibility/networking/10.0/uri-length-limits-removed

for now unfortunately i'm stuck with .NET 8 which is a LTS and still in support - do you have some thoughts about the change @stephentoub ? Thanks

Regression?

Yes 1.0.0-rc2 was working fine

Known Workarounds

No response

Configuration

Microsoft.Extension.Ai 1.0.0-rc5
.NET 8

Other information

No response

[stephentoub]

The issue here isn't DataContent, which stores the urls as strings, not Uri, exactly because of the length limit pre .NET 10.

The issue here is that the OpenAI library chose to switch from using string to only support Uri for this case:
openai/openai-dotnet#934
cc: @jsquire, @joseharriaga

Given that, we don't really have a choice: when constructing the Responses image part, the API requires providing a Uri. The exception you're getting is from doing that:

ResponseContentPart.CreateInputImagePart(new Uri(dataContent.Uri), ...)

Personally, I think the OpenAI change should be reverted, but that's an issue for https://github.com/openai/openai-dotnet.

(Separately, I'm not sure what versions you're referring to with numbers like Microsoft.Extension.Ai 1.0.0-rc5... that doesn't map to any M.E.AI version.)

[nor0x]

thanks for the fast response and the information! My bad with the version info - i'm using MEAI via Agent Framework (i just added the MEAI version to the original issue)