File size: 10,717 Bytes
ed4d993
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
"""Wrapper around Perplexity APIs."""

from __future__ import annotations

import logging
from typing import (
    Any,
    Dict,
    Iterator,
    List,
    Mapping,
    Optional,
    Tuple,
    Type,
    Union,
)

from langchain_core.callbacks import CallbackManagerForLLMRun
from langchain_core.language_models.chat_models import (
    BaseChatModel,
    generate_from_stream,
)
from langchain_core.messages import (
    AIMessage,
    AIMessageChunk,
    BaseMessage,
    BaseMessageChunk,
    ChatMessage,
    ChatMessageChunk,
    FunctionMessageChunk,
    HumanMessage,
    HumanMessageChunk,
    SystemMessage,
    SystemMessageChunk,
    ToolMessageChunk,
)
from langchain_core.outputs import ChatGeneration, ChatGenerationChunk, ChatResult
from langchain_core.pydantic_v1 import Field, root_validator
from langchain_core.utils import get_from_dict_or_env, get_pydantic_field_names

logger = logging.getLogger(__name__)


class ChatPerplexity(BaseChatModel):
    """`Perplexity AI` Chat models API.

    To use, you should have the ``openai`` python package installed, and the
    environment variable ``PPLX_API_KEY`` set to your API key.
    Any parameters that are valid to be passed to the openai.create call can be passed
    in, even if not explicitly saved on this class.

    Example:
        .. code-block:: python

            from langchain_community.chat_models import ChatPerplexity

            chat = ChatPerplexity(model="pplx-70b-online", temperature=0.7)
    """

    client: Any  #: :meta private:
    model: str = "pplx-70b-online"
    """Model name."""
    temperature: float = 0.7
    """What sampling temperature to use."""
    model_kwargs: Dict[str, Any] = Field(default_factory=dict)
    """Holds any model parameters valid for `create` call not explicitly specified."""
    pplx_api_key: Optional[str] = Field(None, alias="api_key")
    """Base URL path for API requests, 
    leave blank if not using a proxy or service emulator."""
    request_timeout: Optional[Union[float, Tuple[float, float]]] = Field(
        None, alias="timeout"
    )
    """Timeout for requests to PerplexityChat completion API. Default is 600 seconds."""
    max_retries: int = 6
    """Maximum number of retries to make when generating."""
    streaming: bool = False
    """Whether to stream the results or not."""
    max_tokens: Optional[int] = None
    """Maximum number of tokens to generate."""

    class Config:
        """Configuration for this pydantic object."""

        allow_population_by_field_name = True

    @property
    def lc_secrets(self) -> Dict[str, str]:
        return {"pplx_api_key": "PPLX_API_KEY"}

    @root_validator(pre=True, allow_reuse=True)
    def build_extra(cls, values: Dict[str, Any]) -> Dict[str, Any]:
        """Build extra kwargs from additional params that were passed in."""
        all_required_field_names = get_pydantic_field_names(cls)
        extra = values.get("model_kwargs", {})
        for field_name in list(values):
            if field_name in extra:
                raise ValueError(f"Found {field_name} supplied twice.")
            if field_name not in all_required_field_names:
                logger.warning(
                    f"""WARNING! {field_name} is not a default parameter.
                    {field_name} was transferred to model_kwargs.
                    Please confirm that {field_name} is what you intended."""
                )
                extra[field_name] = values.pop(field_name)

        invalid_model_kwargs = all_required_field_names.intersection(extra.keys())
        if invalid_model_kwargs:
            raise ValueError(
                f"Parameters {invalid_model_kwargs} should be specified explicitly. "
                f"Instead they were passed in as part of `model_kwargs` parameter."
            )

        values["model_kwargs"] = extra
        return values

    @root_validator(allow_reuse=True)
    def validate_environment(cls, values: Dict) -> Dict:
        """Validate that api key and python package exists in environment."""
        values["pplx_api_key"] = get_from_dict_or_env(
            values, "pplx_api_key", "PPLX_API_KEY"
        )
        try:
            import openai
        except ImportError:
            raise ImportError(
                "Could not import openai python package. "
                "Please install it with `pip install openai`."
            )
        try:
            values["client"] = openai.OpenAI(
                api_key=values["pplx_api_key"], base_url="https://api.perplexity.ai"
            )
        except AttributeError:
            raise ValueError(
                "`openai` has no `ChatCompletion` attribute, this is likely "
                "due to an old version of the openai package. Try upgrading it "
                "with `pip install --upgrade openai`."
            )
        return values

    @property
    def _default_params(self) -> Dict[str, Any]:
        """Get the default parameters for calling PerplexityChat API."""
        return {
            "request_timeout": self.request_timeout,
            "max_tokens": self.max_tokens,
            "stream": self.streaming,
            "temperature": self.temperature,
            **self.model_kwargs,
        }

    def _convert_message_to_dict(self, message: BaseMessage) -> Dict[str, Any]:
        if isinstance(message, ChatMessage):
            message_dict = {"role": message.role, "content": message.content}
        elif isinstance(message, SystemMessage):
            message_dict = {"role": "system", "content": message.content}
        elif isinstance(message, HumanMessage):
            message_dict = {"role": "user", "content": message.content}
        elif isinstance(message, AIMessage):
            message_dict = {"role": "assistant", "content": message.content}
        else:
            raise TypeError(f"Got unknown type {message}")
        return message_dict

    def _create_message_dicts(
        self, messages: List[BaseMessage], stop: Optional[List[str]]
    ) -> Tuple[List[Dict[str, Any]], Dict[str, Any]]:
        params = dict(self._invocation_params)
        if stop is not None:
            if "stop" in params:
                raise ValueError("`stop` found in both the input and default params.")
            params["stop"] = stop
        message_dicts = [self._convert_message_to_dict(m) for m in messages]
        return message_dicts, params

    def _convert_delta_to_message_chunk(
        self, _dict: Mapping[str, Any], default_class: Type[BaseMessageChunk]
    ) -> BaseMessageChunk:
        role = _dict.get("role")
        content = _dict.get("content") or ""
        additional_kwargs: Dict = {}
        if _dict.get("function_call"):
            function_call = dict(_dict["function_call"])
            if "name" in function_call and function_call["name"] is None:
                function_call["name"] = ""
            additional_kwargs["function_call"] = function_call
        if _dict.get("tool_calls"):
            additional_kwargs["tool_calls"] = _dict["tool_calls"]

        if role == "user" or default_class == HumanMessageChunk:
            return HumanMessageChunk(content=content)
        elif role == "assistant" or default_class == AIMessageChunk:
            return AIMessageChunk(content=content, additional_kwargs=additional_kwargs)
        elif role == "system" or default_class == SystemMessageChunk:
            return SystemMessageChunk(content=content)
        elif role == "function" or default_class == FunctionMessageChunk:
            return FunctionMessageChunk(content=content, name=_dict["name"])
        elif role == "tool" or default_class == ToolMessageChunk:
            return ToolMessageChunk(content=content, tool_call_id=_dict["tool_call_id"])
        elif role or default_class == ChatMessageChunk:
            return ChatMessageChunk(content=content, role=role)  # type: ignore[arg-type]
        else:
            return default_class(content=content)  # type: ignore[call-arg]

    def _stream(
        self,
        messages: List[BaseMessage],
        stop: Optional[List[str]] = None,
        run_manager: Optional[CallbackManagerForLLMRun] = None,
        **kwargs: Any,
    ) -> Iterator[ChatGenerationChunk]:
        message_dicts, params = self._create_message_dicts(messages, stop)
        params = {**params, **kwargs}
        default_chunk_class = AIMessageChunk

        if stop:
            params["stop_sequences"] = stop
        stream_resp = self.client.chat.completions.create(
            model=params["model"], messages=message_dicts, stream=True
        )
        for chunk in stream_resp:
            if not isinstance(chunk, dict):
                chunk = chunk.dict()
            if len(chunk["choices"]) == 0:
                continue
            choice = chunk["choices"][0]
            chunk = self._convert_delta_to_message_chunk(
                choice["delta"], default_chunk_class
            )
            finish_reason = choice.get("finish_reason")
            generation_info = (
                dict(finish_reason=finish_reason) if finish_reason is not None else None
            )
            default_chunk_class = chunk.__class__
            chunk = ChatGenerationChunk(message=chunk, generation_info=generation_info)
            if run_manager:
                run_manager.on_llm_new_token(chunk.text, chunk=chunk)
            yield chunk

    def _generate(
        self,
        messages: List[BaseMessage],
        stop: Optional[List[str]] = None,
        run_manager: Optional[CallbackManagerForLLMRun] = None,
        **kwargs: Any,
    ) -> ChatResult:
        if self.streaming:
            stream_iter = self._stream(
                messages, stop=stop, run_manager=run_manager, **kwargs
            )
            if stream_iter:
                return generate_from_stream(stream_iter)
        message_dicts, params = self._create_message_dicts(messages, stop)
        params = {**params, **kwargs}
        response = self.client.chat.completions.create(
            model=params["model"], messages=message_dicts
        )
        message = AIMessage(content=response.choices[0].message.content)
        return ChatResult(generations=[ChatGeneration(message=message)])

    @property
    def _invocation_params(self) -> Mapping[str, Any]:
        """Get the parameters used to invoke the model."""
        pplx_creds: Dict[str, Any] = {
            "api_key": self.pplx_api_key,
            "api_base": "https://api.perplexity.ai",
            "model": self.model,
        }
        return {**pplx_creds, **self._default_params}

    @property
    def _llm_type(self) -> str:
        """Return type of chat model."""
        return "perplexitychat"