【v0.2】'str' object has no attribute 'model_dump'

[sichenyong]

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Example Code

import os
from langchain_openai import ChatOpenAI
from langchain_core.messages import HumanMessage, SystemMessage

os.environ['OPENAI_API_KEY'] = 'sk-xxx'
model = ChatOpenAI(openai_api_base="proxy_website")
messages = [
    SystemMessage(content="Translate the following from English into chinese"),
    HumanMessage(content="hi!"),
]

model.invoke(messages)

Description

I followed the official tutorial to run a simple chat case like this:

url: https://python.langchain.com/v0.2/docs/tutorials/llm_chain/#detailed-walkthrough

I meet some troubles:

---------------------------------------------------------------------------
AttributeError                            Traceback (most recent call last)
Cell In[6], [line 6](vscode-notebook-cell:?execution_count=6&line=6)
      [1](vscode-notebook-cell:?execution_count=6&line=1) messages = [
      [2](vscode-notebook-cell:?execution_count=6&line=2)     SystemMessage(content="Translate the following from English into chinese"),
      [3](vscode-notebook-cell:?execution_count=6&line=3)     HumanMessage(content="hi!"),
      [4](vscode-notebook-cell:?execution_count=6&line=4) ]
----> [6](vscode-notebook-cell:?execution_count=6&line=6) model.invoke(messages)

File D:\SoftWare\environemnt\myenvs\langchain\Lib\site-packages\langchain_core\language_models\chat_models.py:170, in BaseChatModel.invoke(self, input, config, stop, **kwargs)
    [159](file:///D:/SoftWare/environemnt/myenvs/langchain/Lib/site-packages/langchain_core/language_models/chat_models.py:159) def invoke(
    [160](file:///D:/SoftWare/environemnt/myenvs/langchain/Lib/site-packages/langchain_core/language_models/chat_models.py:160)     self,
    [161](file:///D:/SoftWare/environemnt/myenvs/langchain/Lib/site-packages/langchain_core/language_models/chat_models.py:161)     input: LanguageModelInput,
   (...)
    [165](file:///D:/SoftWare/environemnt/myenvs/langchain/Lib/site-packages/langchain_core/language_models/chat_models.py:165)     **kwargs: Any,
    [166](file:///D:/SoftWare/environemnt/myenvs/langchain/Lib/site-packages/langchain_core/language_models/chat_models.py:166) ) -> BaseMessage:
    [167](file:///D:/SoftWare/environemnt/myenvs/langchain/Lib/site-packages/langchain_core/language_models/chat_models.py:167)     config = ensure_config(config)
    [168](file:///D:/SoftWare/environemnt/myenvs/langchain/Lib/site-packages/langchain_core/language_models/chat_models.py:168)     return cast(
    [169](file:///D:/SoftWare/environemnt/myenvs/langchain/Lib/site-packages/langchain_core/language_models/chat_models.py:169)         ChatGeneration,
--> [170](file:///D:/SoftWare/environemnt/myenvs/langchain/Lib/site-packages/langchain_core/language_models/chat_models.py:170)         self.generate_prompt(
    [171](file:///D:/SoftWare/environemnt/myenvs/langchain/Lib/site-packages/langchain_core/language_models/chat_models.py:171)             [self._convert_input(input)],
    [172](file:///D:/SoftWare/environemnt/myenvs/langchain/Lib/site-packages/langchain_core/language_models/chat_models.py:172)             stop=stop,
    [173](file:///D:/SoftWare/environemnt/myenvs/langchain/Lib/site-packages/langchain_core/language_models/chat_models.py:173)             callbacks=config.get("callbacks"),
    [174](file:///D:/SoftWare/environemnt/myenvs/langchain/Lib/site-packages/langchain_core/language_models/chat_models.py:174)             tags=config.get("tags"),
    [175](file:///D:/SoftWare/environemnt/myenvs/langchain/Lib/site-packages/langchain_core/language_models/chat_models.py:175)             metadata=config.get("metadata"),
...
    [545](file:///D:/SoftWare/environemnt/myenvs/langchain/Lib/site-packages/langchain_openai/chat_models/base.py:545) # will throw a "TypeError: 'NoneType' object is not iterable" error
    [546](file:///D:/SoftWare/environemnt/myenvs/langchain/Lib/site-packages/langchain_openai/chat_models/base.py:546) # to mask the true error. Because 'response["choices"]' is None.
    [547](file:///D:/SoftWare/environemnt/myenvs/langchain/Lib/site-packages/langchain_openai/chat_models/base.py:547) if response.get("error"):

AttributeError: 'str' object has no attribute 'model_dump'

System Info

python Python 3.9.13
langchain 0.2.1
langchain-core 0.2.1
langchain-openai 0.1.7
langchain-text-splitters 0.2.0
langsmith 0.1.63

[dosubot[bot]]

Hi @sichenyong! I'm here to help you with any bugs, questions, or contributions you have. 😊

To resolve the AttributeError: 'str' object has no attribute 'model_dump' when running your code, ensure you are using the correct class and method from the LangChain library. The error suggests that a string is being used where an object with a model_dump method is expected.

Here's an example of how to correctly use the ChatOpenAI class from the LangChain library:

import os
from langchain_openai import ChatOpenAI
from langchain_core.messages import HumanMessage, SystemMessage

os.environ['OPENAI_API_KEY'] = 'sk-xxx'
model = ChatOpenAI(openai_api_base="proxy_website")
messages = [
    SystemMessage(content="Translate the following from English into Chinese"),
    HumanMessage(content="hi!"),
]

response = model.invoke(messages)
print(response)

Ensure that you have the correct versions of the dependencies installed. According to the pyproject.toml file, the required versions are:

• python: ">=3.8.1,<4.0"
• langchain-core: ">=0.2.2rc1,<0.3"
• openai: "^1.26.0"
• tiktoken: ">=0.7,<1" ^[1].

Additionally, make sure your imports are correct and that you are using the ChatOpenAI class from the langchain_openai module. If you encounter any issues with the environment setup, refer to the LangChain documentation for further guidance ^[2][3].

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[baskaryan]

hm, seems like you're using a proxy is that right? do you see this issue when requests are sent to openai directly (without proxy)?

[sichenyong]

Maybe there is something wrong withthe proxy website, it work out correctly when I switch to use TongYi

# https://help.aliyun.com/zh/dashscope/developer-reference/compatibility-of-openai-with-dashscope/
os.environ['OPENAI_API_KEY'] = 'your dashboard key' # go to create the api key：https://help.aliyun.com/zh/dashscope/developer-reference/activate-dashscope-and-create-an-api-key
model = ChatOpenAI(model="qwen-turbo",base_url='https://dashscope.aliyuncs.com/compatible-mode/v1')

[ManishAradwad]

Hi, can you elaborate furthur on the solution? I'm using the correct base_url which works with the openai api correctly. But when I use langchain for it, it gives me this error.

[sichenyong]

I'am sorry, I don't keep eye on it

[hechty]

当你用openai代理时, 尝试在url后面加/v1, 如https://xxxx.xxxx.io/v1

[FireCaramelPudding]

your answer is very helpful!

[Wayne857]

Thank you, the answer is very helpful

[wu-diu-diu]

thank you , that is correct !!!