add basic chat app

.gitignore

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+.ipynb_checkpoints

app.py

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+import os
+
+from langchain.chains import LLMChain
+from langchain.chat_models import ChatOpenAI
+from langchain.prompts.chat import (
+ChatPromptTemplate,
+MessagesPlaceholder,
+SystemMessagePromptTemplate,
+HumanMessagePromptTemplate,
+)
+from langchain.memory import ConversationBufferWindowMemory
+from langchain.schema import AIMessage, HumanMessage
+import streamlit as st
+
+
+@st.cache_resource
+def set_api_key(api_key):
+    os.environ["OPENAI_API_KEY"] = api_key
+
+
+@st.cache_resource
+def get_chain(model_name, temperature):
+    llm = ChatOpenAI(model_name=model_name, temperature=temperature)
+    memory = ConversationBufferWindowMemory(k=3, memory_key="chat_history", return_messages=True)
+    prompt = ChatPromptTemplate(
+    messages=[
+        SystemMessagePromptTemplate.from_template(
+            "You are a nice chatbot having a conversation with a human."
+        ),
+        MessagesPlaceholder(variable_name="chat_history"),
+        HumanMessagePromptTemplate.from_template("{input}")
+    ]
+    )
+    conversation = LLMChain(
+                    llm=llm,
+                    prompt=prompt,
+                    verbose=True,
+                    memory=memory
+                )
+    return conversation
+
+
+def display_messages(chain):
+    """
+    Show the messages in the conversation buffer.
+    """
+    for message in chain.memory.buffer:
+        if isinstance(message, AIMessage):
+            role = "assistant"
+        elif isinstance(message, HumanMessage):
+            role = "user"
+        with st.chat_message(role):
+            st.write(message.content)
+            
+
+if __name__ == "__main__":
+    st.header("Basic chatbot")
+    with st.expander("How conversation history works"):
+        st.write("To keep input lengths down and costs reasonable,"
+                 " this bot only 'remembers' the past three turns of conversation.")
+        st.write("Each combination of model type and temperature has its own unique chat history.")
+        st.write("To clear the current model's memory and start fresh, click 'Clear history'" )
+    API_KEY = st.sidebar.text_input(
+    'API Key',
+    type='password',
+    help="Enter your OpenAI API key to use this app",
+    value=None)
+
+    model_name = st.sidebar.selectbox(
+        label = "Choose a model",
+        options = ["gpt-3.5-turbo", "gpt-4"],
+        help="Which LLM to use",
+        )
+    
+    temperature = st.sidebar.slider(
+        label="Temperature",
+        min_value=float(0),
+        max_value=1.0,
+        step=0.1,
+        value=0.9,
+        help="Set the decoding temperature. Lower temperatures give more predictable outputs."
+        )
+    
+    if API_KEY is not None:
+        set_api_key(API_KEY)
+        chain = get_chain(model_name, temperature)
+        if st.button("Clear history"):
+            chain.memory.clear()
+        display_messages(chain)
+        text = st.chat_input()
+        if text:
+            if text.lower() == "clear":
+                chain.memory.clear()
+            else:
+                result = chain.predict(input=text)
+                display_messages(chain)
+
+
+
+
+
+    
+        
+    
+    
+    
+    

requirements.txt

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+langchain
+openai
+streamlit