dify/api/core/tools/utils/message_transformer.py

import logging
from mimetypes import guess_extension

from core.file.file_obj import FileTransferMethod, FileType
from core.tools.entities.tool_entities import ToolInvokeMessage
from core.tools.tool_file_manager import ToolFileManager

logger = logging.getLogger(__name__)


class ToolFileMessageTransformer:
    @classmethod
    def transform_tool_invoke_messages(
        cls, messages: list[ToolInvokeMessage], user_id: str, tenant_id: str, conversation_id: str
    ) -> list[ToolInvokeMessage]:
        """
        Transform tool message and handle file download
        """
        result = []

        for message in messages:
            if message.type == ToolInvokeMessage.MessageType.TEXT or message.type == ToolInvokeMessage.MessageType.LINK:
                result.append(message)
            elif message.type == ToolInvokeMessage.MessageType.IMAGE:
                # try to download image
                try:
                    file = ToolFileManager.create_file_by_url(
                        user_id=user_id, tenant_id=tenant_id, conversation_id=conversation_id, file_url=message.message
                    )

                    url = f'/files/tools/{file.id}{guess_extension(file.mimetype) or ".png"}'

                    result.append(
                        ToolInvokeMessage(
                            type=ToolInvokeMessage.MessageType.IMAGE_LINK,
                            message=url,
                            save_as=message.save_as,
                            meta=message.meta.copy() if message.meta is not None else {},
                        )
                    )
                except Exception as e:
                    logger.exception(e)
                    result.append(
                        ToolInvokeMessage(
                            type=ToolInvokeMessage.MessageType.TEXT,
                            message=f"Failed to download image: {message.message}, please try to download it manually.",
                            meta=message.meta.copy() if message.meta is not None else {},
                            save_as=message.save_as,
                        )
                    )
            elif message.type == ToolInvokeMessage.MessageType.BLOB:
                # get mime type and save blob to storage
                mimetype = message.meta.get("mime_type", "octet/stream")
                # if message is str, encode it to bytes
                if isinstance(message.message, str):
                    message.message = message.message.encode("utf-8")

                file = ToolFileManager.create_file_by_raw(
                    user_id=user_id,
                    tenant_id=tenant_id,
                    conversation_id=conversation_id,
                    file_binary=message.message,
                    mimetype=mimetype,
                )

                url = cls.get_tool_file_url(file.id, guess_extension(file.mimetype))

                # check if file is image
                if "image" in mimetype:
                    result.append(
                        ToolInvokeMessage(
                            type=ToolInvokeMessage.MessageType.IMAGE_LINK,
                            message=url,
                            save_as=message.save_as,
                            meta=message.meta.copy() if message.meta is not None else {},
                        )
                    )
                else:
                    result.append(
                        ToolInvokeMessage(
                            type=ToolInvokeMessage.MessageType.LINK,
                            message=url,
                            save_as=message.save_as,
                            meta=message.meta.copy() if message.meta is not None else {},
                        )
                    )
            elif message.type == ToolInvokeMessage.MessageType.FILE_VAR:
                file_var = message.meta.get("file_var")
                if file_var:
                    if file_var.transfer_method == FileTransferMethod.TOOL_FILE:
                        url = cls.get_tool_file_url(file_var.related_id, file_var.extension)
                        if file_var.type == FileType.IMAGE:
                            result.append(
                                ToolInvokeMessage(
                                    type=ToolInvokeMessage.MessageType.IMAGE_LINK,
                                    message=url,
                                    save_as=message.save_as,
                                    meta=message.meta.copy() if message.meta is not None else {},
                                )
                            )
                        else:
                            result.append(
                                ToolInvokeMessage(
                                    type=ToolInvokeMessage.MessageType.LINK,
                                    message=url,
                                    save_as=message.save_as,
                                    meta=message.meta.copy() if message.meta is not None else {},
                                )
                            )
            else:
                result.append(message)

        return result

    @classmethod
    def get_tool_file_url(cls, tool_file_id: str, extension: str) -> str:
        return f'/files/tools/{tool_file_id}{extension or ".bin"}'