community[patch]: Update the default api_url and reqeust_body of sparkllm embedding (#22136)

- **Description:** When I was running the SparkLLMTextEmbeddings,
app_id, api_key and api_secret are all correct, but it cannot run
normally using the current URL.

    ```python
    # example
    from langchain_community.embeddings import SparkLLMTextEmbeddings

    embedding= SparkLLMTextEmbeddings(
        spark_app_id="my-app-id",
        spark_api_key="my-api-key",
        spark_api_secret="my-api-secret"
    )
    embedding= "hello"
    print(spark.embed_query(text1))
    ```

![sparkembedding](https://github.com/langchain-ai/langchain/assets/55082429/11daa853-4f67-45b2-aae2-c95caa14e38c)
   
So I updated the url and request body parameters according to
[Embedding_api](https://www.xfyun.cn/doc/spark/Embedding_api.html), now
it is runnable.

libs/community/langchain_community/embeddings/sparkllm.py

@@ -5,25 +5,20 @@ import json
 import logging
 from datetime import datetime
 from time import mktime
-from typing import Any, Dict, List, Optional
+from typing import Any, Dict, List, Literal, Optional
 from urllib.parse import urlencode
 from wsgiref.handlers import format_date_time
 
 import numpy as np
 import requests
 from langchain_core.embeddings import Embeddings
-from langchain_core.pydantic_v1 import BaseModel, SecretStr, root_validator
+from langchain_core.pydantic_v1 import BaseModel, Field, SecretStr, root_validator
 from langchain_core.utils import convert_to_secret_str, get_from_dict_or_env
 from numpy import ndarray
 
-# Used for document and knowledge embedding
-EMBEDDING_P_API_URL: str = "https://cn-huabei-1.xf-yun.com/v1/private/sa8a05c27"
-# Used for user questions embedding
-EMBEDDING_Q_API_URL: str = "https://cn-huabei-1.xf-yun.com/v1/private/s50d55a16"
-
 # SparkLLMTextEmbeddings is an embedding model provided by iFLYTEK Co., Ltd.. (https://iflytek.com/en/).
 
-# Official Website: https://www.xfyun.cn/doc/spark/Embedding_new_api.html
+# Official Website: https://www.xfyun.cn/doc/spark/Embedding_api.html
 # Developers need to create an application in the console first, use the appid, APIKey,
 # and APISecret provided in the application for authentication,
 # and generate an authentication URL for handshake.
@@ -43,39 +38,89 @@ class Url:
 
 
 class SparkLLMTextEmbeddings(BaseModel, Embeddings):
-    """SparkLLM Text Embedding models."""
+    """SparkLLM Text Embedding models.
 
-    spark_app_id: SecretStr
-    spark_api_key: SecretStr
-    spark_api_secret: SecretStr
+    To use, you should have the environment variable "SPARK_APP_ID","SPARK_API_KEY"
+    and "SPARK_API_SECRET" set your APP_ID, API_KEY and API_SECRET or pass it
+    as a name parameter to the constructor.
+
+    Example:
+        .. code-block:: python
+
+            from langchain_community.embeddings import SparkLLMTextEmbeddings
+
+            embeddings = SparkLLMTextEmbeddings(
+                spark_app_id="your-app-id",
+                spark_api_key="your-api-key",
+                spark_api_secret="your-api-secret"
+            )
+            text = "This is a test query."
+            query_result = embeddings.embed_query(text)
+
+    """
+
+    spark_app_id: Optional[SecretStr] = Field(default=None, alias="app_id")
+    """Automatically inferred from env var `SPARK_APP_ID` if not provided."""
+    spark_api_key: Optional[SecretStr] = Field(default=None, alias="api_key")
+    """Automatically inferred from env var `SPARK_API_KEY` if not provided."""
+    spark_api_secret: Optional[SecretStr] = Field(default=None, alias="api_secret")
+    """Automatically inferred from env var `SPARK_API_SECRET` if not provided."""
+    base_url: str = Field(default="https://emb-cn-huabei-1.xf-yun.com/")
+    """Base URL path for API requests"""
+    domain: Literal["para", "query"] = Field(default="para")
+    """This parameter is used for which Embedding this time belongs to.
+    If "para"(default), it belongs to document Embedding. 
+    If "query", it belongs to query Embedding."""
+
+    class Config:
+        """Configuration for this pydantic object"""
+
+        allow_population_by_field_name = True
 
     @root_validator(allow_reuse=True)
     def validate_environment(cls, values: Dict) -> Dict:
         """Validate that auth token exists in environment."""
-        cls.spark_app_id = convert_to_secret_str(
+        values["spark_app_id"] = convert_to_secret_str(
             get_from_dict_or_env(values, "spark_app_id", "SPARK_APP_ID")
         )
-        cls.spark_api_key = convert_to_secret_str(
+        values["spark_api_key"] = convert_to_secret_str(
             get_from_dict_or_env(values, "spark_api_key", "SPARK_API_KEY")
         )
-        cls.spark_api_secret = convert_to_secret_str(
+        values["spark_api_secret"] = convert_to_secret_str(
             get_from_dict_or_env(values, "spark_api_secret", "SPARK_API_SECRET")
         )
         return values
 
     def _embed(self, texts: List[str], host: str) -> Optional[List[List[float]]]:
+        """Internal method to call Spark Embedding API and return embeddings.
+
+        Args:
+            texts: A list of texts to embed.
+            host: Base URL path for API requests
+
+        Returns:
+            A list of list of floats representing the embeddings,
+            or list with value None if an error occurs.
+        """
+        app_id = ""
+        api_key = ""
+        api_secret = ""
+        if self.spark_app_id:
+            app_id = self.spark_app_id.get_secret_value()
+        if self.spark_api_key:
+            api_key = self.spark_api_key.get_secret_value()
+        if self.spark_api_secret:
+            api_secret = self.spark_api_secret.get_secret_value()
         url = self._assemble_ws_auth_url(
             request_url=host,
             method="POST",
-            api_key=self.spark_api_key.get_secret_value(),
-            api_secret=self.spark_api_secret.get_secret_value(),
+            api_key=api_key,
+            api_secret=api_secret,
         )
         embed_result: list = []
         for text in texts:
             query_context = {"messages": [{"content": text, "role": "user"}]}
-            content = self._get_body(
-                self.spark_app_id.get_secret_value(), query_context
-            )
+            content = self._get_body(app_id, query_context)
             response = requests.post(
                 url, json=content, headers={"content-type": "application/json"}
             ).text
@@ -95,7 +140,7 @@ class SparkLLMTextEmbeddings(BaseModel, Embeddings):
         Returns:
             A list of embeddings, one for each text, or None if an error occurs.
         """
-        return self._embed(texts, EMBEDDING_P_API_URL)
+        return self._embed(texts, self.base_url)
 
     def embed_query(self, text: str) -> Optional[List[float]]:  # type: ignore[override]
         """Public method to get embedding for a single query text.
@@ -106,7 +151,7 @@ class SparkLLMTextEmbeddings(BaseModel, Embeddings):
         Returns:
             Embeddings for the text, or None if an error occurs.
         """
-        result = self._embed([text], EMBEDDING_Q_API_URL)
+        result = self._embed([text], self.base_url)
         return result[0] if result is not None else None
 
     @staticmethod
@@ -151,11 +196,12 @@ class SparkLLMTextEmbeddings(BaseModel, Embeddings):
         u = Url(host, path, schema)
         return u
 
-    @staticmethod
-    def _get_body(appid: str, text: dict) -> Dict[str, Any]:
+    def _get_body(self, appid: str, text: dict) -> Dict[str, Any]:
         body = {
             "header": {"app_id": appid, "uid": "39769795890", "status": 3},
-            "parameter": {"emb": {"feature": {"encoding": "utf8"}}},
+            "parameter": {
+                "emb": {"domain": self.domain, "feature": {"encoding": "utf8"}}
+            },
             "payload": {
                 "messages": {
                     "text": base64.b64encode(json.dumps(text).encode("utf-8")).decode()

libs/community/tests/unit_tests/embeddings/test_sparkllm.py

@@ -0,0 +1,47 @@
+import os
+from typing import cast
+
+import pytest
+from langchain_core.pydantic_v1 import SecretStr, ValidationError
+
+from langchain_community.embeddings import SparkLLMTextEmbeddings
+
+
+def test_sparkllm_initialization_by_alias() -> None:
+    # Effective initialization
+    embeddings = SparkLLMTextEmbeddings(
+        app_id="your-app-id",  # type: ignore[arg-type]
+        api_key="your-api-key",  # type: ignore[arg-type]
+        api_secret="your-api-secret",  # type: ignore[arg-type]
+    )
+    assert cast(SecretStr, embeddings.spark_app_id).get_secret_value() == "your-app-id"
+    assert (
+        cast(SecretStr, embeddings.spark_api_key).get_secret_value() == "your-api-key"
+    )
+    assert (
+        cast(SecretStr, embeddings.spark_api_secret).get_secret_value()
+        == "your-api-secret"
+    )
+
+
+def test_initialization_parameters_from_env() -> None:
+    # Setting environment variable
+    os.environ["SPARK_APP_ID"] = "your-app-id"
+    os.environ["SPARK_API_KEY"] = "your-api-key"
+    os.environ["SPARK_API_SECRET"] = "your-api-secret"
+
+    # Effective initialization
+    embeddings = SparkLLMTextEmbeddings()
+    assert cast(SecretStr, embeddings.spark_app_id).get_secret_value() == "your-app-id"
+    assert (
+        cast(SecretStr, embeddings.spark_api_key).get_secret_value() == "your-api-key"
+    )
+    assert (
+        cast(SecretStr, embeddings.spark_api_secret).get_secret_value()
+        == "your-api-secret"
+    )
+
+    # Environment variable missing
+    del os.environ["SPARK_APP_ID"]
+    with pytest.raises(ValidationError):
+        SparkLLMTextEmbeddings()