[Frontend] Support simpler image input format (vllm-project#9478)

Signed-off-by: charlifu <[email protected]>

tests/entrypoints/test_chat_utils.py

@@ -388,3 +388,29 @@ def test_parse_chat_messages_rejects_too_many_images_across_messages(
                     "text": "What about these two?"
                 }]
             }], phi3v_model_config, phi3v_tokenizer)
+
+
+def test_parse_chat_messages_multiple_images_uncommon_input(
+    phi3v_model_config,
+    phi3v_tokenizer,
+    image_url,
+):
+    conversation, mm_data = parse_chat_messages([{
+        "role":
+        "user",
+        "content": [
+            "What's in these images?", {
+                "image_url": image_url
+            }, {
+                "image_url": image_url
+            }
+        ]
+    }], phi3v_model_config, phi3v_tokenizer)
+
+    assert conversation == [{
+        "role":
+        "user",
+        "content":
+        "<|image_1|>\n<|image_2|>\nWhat's in these images?"
+    }]
+    _assert_mm_data_is_image_input(mm_data, 2)

vllm/entrypoints/chat_utils.py

@@ -5,8 +5,8 @@
 from collections import defaultdict
 from functools import lru_cache, partial
 from pathlib import Path
-from typing import (Any, Awaitable, Dict, Generic, Iterable, List, Literal,
-                    Mapping, Optional, Tuple, TypeVar, Union, cast)
+from typing import (Any, Awaitable, Callable, Dict, Generic, Iterable, List,
+                    Literal, Mapping, Optional, Tuple, TypeVar, Union, cast)
 
 # yapf conflicts with isort for this block
 # yapf: disable
@@ -59,10 +59,35 @@ class CustomChatCompletionContentPartParam(TypedDict, total=False):
     """The type of the content part."""
 
 
+class CustomChatCompletionContentSimpleImageParam(TypedDict, total=False):
+    """A simpler version of the param that only accepts a plain image_url.
+    This is supported by OpenAI API, although it is not documented.
+    
+    Example:
+    {
+        "image_url": "https://example.com/image.jpg"
+    }
+    """
+    image_url: Required[str]
+
+
+class CustomChatCompletionContentSimpleAudioParam(TypedDict, total=False):
+    """A simpler version of the param that only accepts a plain audio_url.
+    
+    Example:
+    {
+        "audio_url": "https://example.com/audio.mp3"
+    }
+    """
+    audio_url: Required[str]
+
+
 ChatCompletionContentPartParam: TypeAlias = Union[
     OpenAIChatCompletionContentPartParam, ChatCompletionContentPartAudioParam,
     ChatCompletionContentPartRefusalParam,
-    CustomChatCompletionContentPartParam]
+    CustomChatCompletionContentPartParam,
+    CustomChatCompletionContentSimpleImageParam,
+    CustomChatCompletionContentSimpleAudioParam, str]
 
 
 class CustomChatCompletionMessageParam(TypedDict, total=False):
@@ -387,6 +412,71 @@ def _get_full_multimodal_text_prompt(placeholder_counts: Dict[str, int],
 _RefusalParser = partial(cast, ChatCompletionContentPartRefusalParam)
 MODEL_KEEP_MULTI_MODAL_CONTENT = {'mllama'}
 
+# Define a mapping from part types to their corresponding parsing functions.
+MM_PARSER_MAP: Dict[str, Callable[[ChatCompletionContentPartParam], str]] = {
+    "text":
+    lambda part: _TextParser(part).get("text", ""),
+    "image_url":
+    lambda part: _ImageParser(part).get("image_url", {}).get("url", ""),
+    "audio_url":
+    lambda part: _AudioParser(part).get("audio_url", {}).get("url", ""),
+    "refusal":
+    lambda part: _RefusalParser(part).get("refusal", ""),
+}
+
+
+def _parse_chat_message_content_mm_part(
+        part: ChatCompletionContentPartParam) -> Tuple[str, str]:
+    """
+    Parses a given multi modal content part based on its type.
+
+    Args:
+        part: A dict containing the content part, with a potential 'type' field.
+
+    Returns:
+        A tuple (part_type, content) where:
+        - part_type: Type of the part (e.g., 'text', 'image_url').
+        - content: Parsed content (e.g., text, image URL).
+
+    Raises:
+        ValueError: If the 'type' field is missing and no direct URL is found.
+    """
+    assert isinstance(
+        part, dict)  # This is needed to avoid mypy errors: part.get() from str
+    part_type = part.get("type", None)
+
+    if isinstance(part_type, str) and part_type in MM_PARSER_MAP:
+        content = MM_PARSER_MAP[part_type](part)
+
+        # Special case for 'image_url.detail'
+        if part_type == "image_url" and part.get("detail") != "auto":
+            logger.warning("'image_url.detail' is currently not supported "
+                           "and will be ignored.")
+
+        return part_type, content
+
+    # Handle missing 'type' but provided direct URL fields.
+    if part_type is None:
+        if part.get("image_url") is not None:
+            image_params = cast(CustomChatCompletionContentSimpleImageParam,
+                                part)
+            return "image_url", image_params.get("image_url", "")
+        if part.get("audio_url") is not None:
+            audio_params = cast(CustomChatCompletionContentSimpleAudioParam,
+                                part)
+            return "audio_url", audio_params.get("audio_url", "")
+
+        # Raise an error if no 'type' or direct URL is found.
+        raise ValueError("Missing 'type' field in multimodal part.")
+
+    if not isinstance(part_type, str):
+        raise ValueError("Invalid 'type' field in multimodal part.")
+    return part_type, "unknown part_type content"
+
+
+VALID_MESSAGE_CONTENT_MM_PART_TYPES = ("text", "refusal", "image_url",
+                                       "audio_url")
+
 
 def _parse_chat_message_content_parts(
     role: str,
@@ -402,29 +492,28 @@ def _parse_chat_message_content_parts(
 
     has_image = False
     for part in parts:
-        part_type = part["type"]
-        if part_type == "text":
-            text = _TextParser(part)["text"]
+        if isinstance(part, str):  # Handle plain text parts
+            text = _TextParser(part)
             texts.append(text)
-        elif part_type == "image_url":
-            image_url = _ImageParser(part)["image_url"]
-
-            if image_url.get("detail", "auto") != "auto":
-                logger.warning(
-                    "'image_url.detail' is currently not supported and "
-                    "will be ignored.")
-
-            mm_parser.parse_image(image_url["url"])
-            has_image = True
-        elif part_type == "audio_url":
-            audio_url = _AudioParser(part)["audio_url"]
-
-            mm_parser.parse_audio(audio_url["url"])
-        elif part_type == "refusal":
-            text = _RefusalParser(part)["refusal"]
-            texts.append(text)
-        else:
-            raise NotImplementedError(f"Unknown part type: {part_type}")
+        else:  # Handle structured dictionary parts
+            part_type, content = _parse_chat_message_content_mm_part(part)
+
+            # if part_type is text/refusal/image_url/audio_url but
+            # content is empty, logg a warning and skip
+            if part_type in VALID_MESSAGE_CONTENT_MM_PART_TYPES and not content:
+                logger.warning("Skipping multimodal part "
+                               "with empty / unparsable content.")
+                continue
+
+            if part_type in ("text", "refusal"):
+                texts.append(content)
+            elif part_type == "image_url":
+                mm_parser.parse_image(content)
+                has_image = True
+            elif part_type == "audio_url":
+                mm_parser.parse_audio(content)
+            else:
+                raise NotImplementedError(f"Unknown part type: {part_type}")
 
     text_prompt = "\n".join(texts)
     if keep_multimodal_content: