app.py

import gradio as gr
import time
import base64
from openai import OpenAI
import os
from io import BytesIO
from PIL import Image

# 配置
BASE_URL = "https://api.stepfun.com/v1"
# 从环境变量获取API密钥
STEP_API_KEY = os.environ.get("STEP_API_KEY", "")

# 可选模型
MODELS = ["step-3", "step-r1-v-mini"]

def image_to_base64(image):
    """将PIL图像转换为base64字符串"""
    if image is None:
        return None
    
    if isinstance(image, Image.Image):
        buffered = BytesIO()
        image.save(buffered, format="PNG")
        img_str = base64.b64encode(buffered.getvalue()).decode()
        return img_str
    
    return None

def call_step_api(image, prompt, model, temperature=0.7, max_tokens=2000):
    """调用Step API进行图像分析和文本生成，支持CoT推理展示"""
    
    if image is None:
        yield "❌ 请先上传一张图片", ""
        return
    
    if not prompt:
        yield "❌ 请输入提示词", ""
        return
    
    if not STEP_API_KEY:
        yield "❌ API密钥未配置。请在 Hugging Face Space 的 Settings 中添加 STEP_API_KEY 环境变量。", ""
        return
    
    # 转换图像为base64
    try:
        base64_image = image_to_base64(image)
        if base64_image is None:
            yield "❌ 图片处理失败", ""
            return
    except Exception as e:
        yield f"❌ 图片处理错误: {str(e)}", ""
        return
    
    # 构造消息
    messages = [
        {
            "role": "user",
            "content": [
                {
                    "type": "image_url",
                    "image_url": {
                        "url": f"data:image/png;base64,{base64_image}",
                        "detail": "high"
                    }
                },
                {
                    "type": "text",
                    "text": prompt
                }
            ]
        }
    ]
    
    # 创建OpenAI客户端
    try:
        client = OpenAI(api_key=STEP_API_KEY, base_url=BASE_URL)
    except Exception as e:
        yield f"❌ 客户端初始化失败: {str(e)}", ""
        return
    
    try:
        # 记录开始时间
        start_time = time.time()
        
        # 流式输出
        response = client.chat.completions.create(
            model=model,
            messages=messages,
            temperature=temperature,
            max_tokens=max_tokens,
            stream=True
        )
        
        full_response = ""
        reasoning_content = ""
        final_answer = ""
        is_reasoning = False
        reasoning_started = False
        
        for chunk in response:
            if chunk.choices and chunk.choices[0].delta:
                delta = chunk.choices[0].delta
                
                if hasattr(delta, 'content') and delta.content:
                    content = delta.content
                    full_response += content
                    
                    # 检测reasoning标记
                    if "<reasoning>" in content:
                        is_reasoning = True
                        reasoning_started = True
                        # 提取<reasoning>之前的内容添加到final_answer
                        before_reasoning = content.split("<reasoning>")[0]
                        if before_reasoning:
                            final_answer += before_reasoning
                        # 提取<reasoning>之后的内容开始reasoning
                        after_tag = content.split("<reasoning>")[1] if len(content.split("<reasoning>")) > 1 else ""
                        reasoning_content += after_tag
                    elif "</reasoning>" in content:
                        # 提取</reasoning>之前的内容添加到reasoning
                        before_tag = content.split("</reasoning>")[0]
                        reasoning_content += before_tag
                        is_reasoning = False
                        # 提取</reasoning>之后的内容添加到final_answer
                        after_reasoning = content.split("</reasoning>")[1] if len(content.split("</reasoning>")) > 1 else ""
                        final_answer += after_reasoning
                    elif is_reasoning:
                        reasoning_content += content
                    else:
                        final_answer += content
                    
                    # 实时输出
                    if reasoning_started:
                        yield reasoning_content, final_answer
                    else:
                        yield "", final_answer
        
        # 添加生成时间
        elapsed_time = time.time() - start_time
        time_info = f"\n\n⏱️ 生成用时: {elapsed_time:.2f}秒"
        final_answer += time_info
        
        yield reasoning_content, final_answer
                
    except Exception as e:
        error_msg = str(e)
        if "api_key" in error_msg.lower():
            yield "", "❌ API密钥错误：请检查密钥是否有效"
        elif "network" in error_msg.lower() or "connection" in error_msg.lower():
            yield "", "❌ 网络连接错误：请检查网络连接"
        else:
            yield "", f"❌ API调用错误: {error_msg[:200]}"

# 创建Gradio界面
with gr.Blocks(title="Step-3", theme=gr.themes.Soft()) as demo:
    gr.Markdown("""
    # 🤖 Step-3
    """)
    
    with gr.Row():
        with gr.Column(scale=1):
            # 输入区域
            image_input = gr.Image(
                label="上传图片",
                type="pil",
                height=300
            )
            
            prompt_input = gr.Textbox(
                label="提示词",
                placeholder="例如：这是什么？请详细描述",
                lines=3,
                value="请详细描述这张图片的内容。"
            )
            
            with gr.Accordion("高级设置", open=False):
                model_select = gr.Dropdown(
                    choices=MODELS,
                    value=MODELS[0],
                    label="选择模型"
                )
                
                temperature_slider = gr.Slider(
                    minimum=0,
                    maximum=1,
                    value=0.7,
                    step=0.1,
                    label="Temperature"
                )
                
                max_tokens_slider = gr.Slider(
                    minimum=100,
                    maximum=4000,
                    value=2000,
                    step=100,
                    label="最大输出长度"
                )
            
            submit_btn = gr.Button("🚀 开始分析", variant="primary")
            clear_btn = gr.Button("🗑️ 清空", variant="secondary")
        
        with gr.Column(scale=1):
            # 推理过程展示
            with gr.Accordion("💭 推理过程 (CoT)", open=True):
                reasoning_output = gr.Textbox(
                    label="思考过程",
                    lines=10,
                    max_lines=15,
                    show_copy_button=True,
                    interactive=False
                )
            
            # 最终答案展示
            answer_output = gr.Textbox(
                label="📝 分析结果",
                lines=15,
                max_lines=25,
                show_copy_button=True,
                interactive=False
            )
    
    # 事件处理 - 流式输出到两个文本框
    submit_btn.click(
        fn=call_step_api,
        inputs=[
            image_input,
            prompt_input,
            model_select,
            temperature_slider,
            max_tokens_slider
        ],
        outputs=[reasoning_output, answer_output],
        show_progress=True
    )
    
    clear_btn.click(
        fn=lambda: (None, "", "", ""),
        inputs=[],
        outputs=[image_input, prompt_input, reasoning_output, answer_output]
    )
    
    # 页脚
    gr.Markdown("""
    ---
    Powered by [Step-3](https://www.stepfun.com/)
    """)

# 启动应用
if __name__ == "__main__":
    demo.launch()