Feat: update stepfun list (#12991)

### What problem does this PR solve?

Update stepfun list.

Add TTS and Sequence2Text functionalities.

### Type of change

- [x] New Feature (non-breaking change which adds functionality)

rag/llm/sequence2txt_model.py

@@ -59,6 +59,15 @@ class GPTSeq2txt(Base):
         self.model_name = model_name
 
 
+class StepFunSeq2txt(GPTSeq2txt):
+    _FACTORY_NAME = "StepFun"
+
+    def __init__(self, key, model_name="step-asr", lang="Chinese", base_url="https://api.stepfun.com/v1", **kwargs):
+        if not base_url:
+            base_url = "https://api.stepfun.com/v1"
+        super().__init__(key, model_name=model_name, base_url=base_url, **kwargs)
+
+
 class QWenSeq2txt(Base):
     _FACTORY_NAME = "Tongyi-Qianwen"
 

rag/llm/tts_model.py

@@ -19,6 +19,7 @@ import base64
 import hashlib
 import hmac
 import json
+import os
 import queue
 import re
 import ssl
@@ -36,6 +37,7 @@ import requests
 import websocket
 from pydantic import BaseModel, conint
 
+from common.http_client import sync_request
 from common.token_utils import num_tokens_from_string
 
 
@@ -387,6 +389,7 @@ class SILICONFLOWTTS(Base):
             if chunk:
                 yield chunk
 
+
 class DeepInfraTTS(OpenAITTS):
     _FACTORY_NAME = "DeepInfra"
 
@@ -394,7 +397,8 @@ class DeepInfraTTS(OpenAITTS):
         if not base_url:
             base_url = "https://api.deepinfra.com/v1/openai"
         super().__init__(key, model_name, base_url, **kwargs)
-        
+
+
 class CometAPITTS(OpenAITTS):
     _FACTORY_NAME = "CometAPI"
 
@@ -402,7 +406,8 @@ class CometAPITTS(OpenAITTS):
         if not base_url:
             base_url = "https://api.cometapi.com/v1"
         super().__init__(key, model_name, base_url, **kwargs)
-        
+
+
 class DeerAPITTS(OpenAITTS):
     _FACTORY_NAME = "DeerAPI"
 
@@ -410,3 +415,37 @@ class DeerAPITTS(OpenAITTS):
         if not base_url:
             base_url = "https://api.deerapi.com/v1"
         super().__init__(key, model_name, base_url, **kwargs)
+
+
+class StepFunTTS(OpenAITTS):
+    _FACTORY_NAME = "StepFun"
+    _SUPPORTED_RESPONSE_FORMATS = {"wav", "mp3", "flac", "opus", "pcm"}
+
+    def __init__(self, key, model_name, base_url="https://api.stepfun.com/v1", **kwargs):
+        if not base_url:
+            base_url = "https://api.stepfun.com/v1"
+        self.default_voice = os.environ.get("STEPFUN_TTS_VOICE") or "cixingnansheng"
+        super().__init__(key, model_name, base_url, **kwargs)
+
+    def tts(self, text, voice=None, response_format: Literal["wav", "mp3", "flac", "opus", "pcm"] = "mp3"):
+        text = self.normalize_text(text)
+        if response_format not in self._SUPPORTED_RESPONSE_FORMATS:
+            raise ValueError(f"Unsupported response_format={response_format!r}. Supported: {sorted(self._SUPPORTED_RESPONSE_FORMATS)}")
+
+        payload = {
+            "model": self.model_name,
+            "voice": voice or self.default_voice,
+            "input": text,
+            "response_format": response_format,
+        }
+
+        response = sync_request("POST", f"{self.base_url}/audio/speech", headers=self.headers, json=payload)
+
+        if response.status_code != 200:
+            raise Exception(f"**Error**: {response.status_code}, {response.text}")
+
+        for chunk in response.iter_bytes():
+            if chunk:
+                yield chunk
+
+        yield num_tokens_from_string(text)