.Net: Add support for audio, pdf, doc, and docx to chat prompt parser

[glorious-beard]

Motivation and Context

Why is this change required?

This template parsers like the YAML parser to embed content types other than just text and images for LLMs that support additional content types, like PDFs for OpenAI and DOCXs for Claude. Without this capability, functions with prompts that have attachments would have to manually build it's chat history in code.

What problem does it solve?

See above

What scenario does it contribute to?

Usage additional content types beyond visuals and audio for user messages

Open Issues Addressed

• Fixes Expanding ChatPromptParser to handle other content types #11044

Description

Chat Prompt Parser

To preserve backward compatibility, rather than consolidating binary content types, I chose to go with adding additional content types so that LLM chat service providers could opt-in to new content types. It also reduces the chances of breaking existing code.

3 new content types are created:

• PdfContent for PDF files. Uses the tag "<pdf>". Allows for Base64 data URIs or standard URIs, similar to ImageContent.
• DocContent for MS Word .doc files. Uses the tag "<doc>". Allows for Base64 data URIs or standard URIs, similar to ImageContent.
• DocxContent for MS Word .docx files. Uses the tag "<docx>". Allows for Base64 data URIs or standard URIs, similar to ImageContent.

(NOTE: DocContent and DocxContent are mainly separate because they have different MIME types and different content formats, though they could easily be consolidated into a single tag and just let the LLM provider handle distinguishing between "doc" and "docx" files. Alternately, I could also see the case for dropping ".doc" support and requiring the caller to only use ".docx".)

In addition, the following 2 contents are now parsed from the XML:

• AudioContent - Parses the tag "<audio>" with either Base64 data URIs or standard URIs, similar to ImageContent.
• BinaryContent - Parses the tag "<file>" with either Base64 data URIs or standard URIs, similar to ImageContent.

Here is a sample:

            
<message role='user'>
  This part will be discarded upon parsing
  <text>Make sense of this random assortment of stuff.</text>
  <image>https://fake-link-to-image/</image>
  <audio>data:audio/wav;base64,UklGRiQAAABXQVZFZm10IBAAAAABAAEAIlYAAACABAAZGF0YVgAAAAA</audio>
  <pdf>data:application/pdf;base64,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</pdf>
  <pdf>https://fake-link-to-pdf/</pdf>  
 
 <doc>data:application/msword;base64,UEsDBBQAAAAIAI+Q1k5a2gAAABQAAAAIAAAAbmFtZS5kb2N4VVQJAAD9AAAACwAAAB4AAAAAA==</doc>
  <doc>https://fake-link-to-doc/</doc>
  <docx>data:application/vnd.openxmlformats-officedocument.wordprocessingml.document;base64,UEsDBBQAAAAIAI+Q1k5a2gAAABQAAAAIAAAAbmFtZS5kb2N4VVQJAAD9AAAACwAAAB4AAAAAA==</docx>
  <docx>https://fake-link-to-docx/</docx>
  <file>data:application/octet-stream;base64,UEsDBBQAAAAIAI+Q1k5a2gAAABQAAAAIAAAAbmFtZS5kb2N4VVQJAAD9AAAACwAAAB4AAAAAA==</file>
  <file>https://fake-link-to-binary/</file>
  This part will also be discarded upon parsing
</message>

Amazon Bedrock

Modified the Converse API request generator to handle the subset of binary content supported by Amazon Bedrock (PDF, DOC, DOCX, and Image), as documented here.

OpenAI

Modified the client to handle PDF content, audio content, and file references when generating a request to an OpenAI (or OpenAI compatible) client.

Contribution Checklist

• The code builds clean without any errors or warnings
• The PR follows the SK Contribution Guidelines and the pre-submission formatting script raises no violations
• All unit tests pass, and I have added new tests where possible
• I didn't break anyone 😄

[RogerBarreto]

@glorious-beard I updated the proposal to be abstract as this is applied to the SemanticKernel.Abstraction package.

As we will have many different types of documents and binary files, to be more abroad and less specific, is better not introduce any special content types and use the existing ones we already have that works.

Given that updated the logic to accept a mimetype attribute as part of the <binary mimetype="type/subtype"/> to solve the scenarios where you provide a Uri.

For dataUri content, the mimeType is picked automatically from the data:mimeType schema.

[RogerBarreto]

Updated PR Description

Motivation and Context

Enhance the Chat Prompt XML parsing capability to also support audio and documents.

• Fixes Expanding ChatPromptParser to handle other content types #11044

Description

The following 2 contents are now supported from the Chat Prompt XML:

• AudioContent - Parses the tag <audio mimetype="type/subtype"> with either Base64 data URIs or standard URIs, similar to ImageContent.
• BinaryContent - Parses the tag <binary mimetype="type/subtype"> with either Base64 data URIs or standard URIs, similar to ImageContent.

The mimetype attribute is optional, and can be omitted for Base64 data URIs.

Here is a sample:

<message role='user'>
  This part will be discarded upon parsing
  <text>Summarize all the contents I provided in this message.</text>
  <image mimetype="image/png">https://fake-link-to-image/</image>
  <audio>data:audio/wav;base64,UklGRiQAAAB...</audio>
  <binary>data:application/pdf;base64,UklGRiQAAAB...</binary>
  <binary mimetype="application/pdf">https://fake-link-to-pdf/</binary>  
  <binary>data:application/msword;base64,UklGRiQAAAB...</binary>
  <binary mimetype="octet/stream">https://fake-link-to-binary/</binary>
</message>

Contribution Checklist

• The code builds clean without any errors or warnings
• The PR follows the SK Contribution Guidelines and the pre-submission formatting script raises no violations
• All unit tests pass, and I have added new tests where possible
• I didn't break anyone 😄

[SergeyMenshykh]

nit: move this private method down the file after the public one so that all private methods are grouped together.