feat: Custom Open AI API Endpoint (#62)

* 实现可切换的 OpenAI 请求地址功能
* Update README.md

---------

Co-authored-by: huchangzhi <857114841@qq.com>
Co-authored-by: Jazee <jazee@jaze.top>

README.md

@@ -51,6 +51,7 @@ https://developers.cloudflare.com/workers-ai/models/
 | CF_TOKEN       | Cloudflare Workers AI Token        |  
 | CF_GATEWAY     | Cloudflare AI Gateway URL          |    
 | OPENAI_API_KEY | OpenAI API Key (需要ChatGPT时填写)      |     
+| OPENAI_API_URL | 自定义OpenAI API请求地址 |
 | G_API_KEY      | Google AI API Key (需要GeminiPro时填写) | 
 | G_API_URL      | Google AI 反代 (不支持地区填写，或参考以下配置)     |    
 | PASSWORD       | 访问密码 (可选)                          |   

server/api/auth/openai.post.ts

@@ -1,28 +1,33 @@
-import {handleErr, openaiParser, streamResponse} from "~/utils/helper";
-import {OpenAIBody, OpenAIReq} from "~/utils/types";
+import { handleErr, openaiParser, streamResponse } from "~/utils/helper";
+import { OpenAIBody, OpenAIReq } from "~/utils/types";
 
 export default defineEventHandler(async (event) => {
-    const body: OpenAIReq = await readBody(event)
-    const {model, endpoint, messages, key} = body
+    const body: OpenAIReq = await readBody(event);
+    const { model, messages, key } = body;
 
     const openAIBody: OpenAIBody = {
         stream: true,
-        model,
+        model, // 使用传入的模型参数
         messages,
-    }
+    };
+
+    // 检查是否提供了自定义的 OPENAI_API_URL
+    const apiUrl = process.env.OPENAI_API_URL ? 
+        `${process.env.OPENAI_API_URL}/v1/chat/completions` : 
+        `${process.env.CF_GATEWAY}/openai/${endpoint}`; 
 
-    const res = await fetch(`${process.env.CF_GATEWAY}/openai/${endpoint}`, {
+    const res = await fetch(apiUrl, {
         method: 'POST',
         headers: {
             Authorization: key === undefined ? `Bearer ${process.env.OPENAI_API_KEY}` : `Bearer ${key}`,
             'Content-Type': 'application/json',
         },
         body: JSON.stringify(openAIBody),
-    })
+    });
 
     if (!res.ok) {
-        return handleErr(res)
+        return handleErr(res);
     }
 
-    return streamResponse(res, openaiParser)
-})
+    return streamResponse(res, openaiParser);
+});