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https://github.com/zhayujie/chatgpt-on-wechat.git
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74 lines
2.7 KiB
Python
74 lines
2.7 KiB
Python
from bot.session_manager import Session
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from common.log import logger
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class OpenAISession(Session):
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def __init__(self, session_id, system_prompt=None, model="text-davinci-003"):
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super().__init__(session_id, system_prompt)
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self.model = model
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self.reset()
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def __str__(self):
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# 构造对话模型的输入
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"""
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e.g. Q: xxx
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A: xxx
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Q: xxx
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"""
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prompt = ""
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for item in self.messages:
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if item["role"] == "system":
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prompt += item["content"] + "<|endoftext|>\n\n\n"
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elif item["role"] == "user":
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prompt += "Q: " + item["content"] + "\n"
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elif item["role"] == "assistant":
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prompt += "\n\nA: " + item["content"] + "<|endoftext|>\n"
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if len(self.messages) > 0 and self.messages[-1]["role"] == "user":
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prompt += "A: "
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return prompt
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def discard_exceeding(self, max_tokens, cur_tokens=None):
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precise = True
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try:
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cur_tokens = self.calc_tokens()
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except Exception as e:
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precise = False
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if cur_tokens is None:
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raise e
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logger.debug("Exception when counting tokens precisely for query: {}".format(e))
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while cur_tokens > max_tokens:
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if len(self.messages) > 1:
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self.messages.pop(0)
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elif len(self.messages) == 1 and self.messages[0]["role"] == "assistant":
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self.messages.pop(0)
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if precise:
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cur_tokens = self.calc_tokens()
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else:
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cur_tokens = len(str(self))
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break
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elif len(self.messages) == 1 and self.messages[0]["role"] == "user":
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logger.warn("user question exceed max_tokens. total_tokens={}".format(cur_tokens))
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break
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else:
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logger.debug("max_tokens={}, total_tokens={}, len(conversation)={}".format(max_tokens, cur_tokens, len(self.messages)))
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break
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if precise:
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cur_tokens = self.calc_tokens()
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else:
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cur_tokens = len(str(self))
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return cur_tokens
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def calc_tokens(self):
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return num_tokens_from_string(str(self), self.model)
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# refer to https://github.com/openai/openai-cookbook/blob/main/examples/How_to_count_tokens_with_tiktoken.ipynb
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def num_tokens_from_string(string: str, model: str) -> int:
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"""Returns the number of tokens in a text string."""
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import tiktoken
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encoding = tiktoken.encoding_for_model(model)
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num_tokens = len(encoding.encode(string, disallowed_special=()))
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return num_tokens
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