GeminiAI is a large language model that is very developer-friendly. It not only has a beautiful interface and powerful features but also provides a relatively high daily free quota, which is enough to meet daily usage needs.
However, it also has some inconveniences, such as the need to always use a VPN and the API is not compatible with the OpenAI SDK.
To solve these problems and achieve compatibility with OpenAI, I wrote a piece of JavaScript code and deployed it to Cloudflare, binding it to my own domain. This allows me to use Gemini in China without a VPN, while also maintaining OpenAI compatibility. In any tool that uses OpenAI, you can simply replace the API address and secret key (SK).
Creating a Worker on Cloudflare
If you don't have a Cloudflare account yet, please register for one (free). The registration address is: https://dash.cloudflare.com/ After logging in, remember to bind your own domain name, otherwise, you will not be able to achieve proxy-free access.
After logging in, find Compute (Workers) in the left sidebar and click it, then click the Create button.
On the page that appears, click Create Worker.
Then click Deploy in the lower right corner to complete the creation of the Worker.
Editing the Code
The following code is the key to achieving OpenAI compatibility. Please copy it and replace the default code generated in the Worker.
On the page after the deployment is complete, click Edit code.
Delete all the code on the left, then copy and paste the following code, and finally click Deploy in the upper right corner.
Copy the following code
export default {
async fetch (request) {
if (request.method === "OPTIONS") {
return handleOPTIONS();
}
const errHandler = (err) => {
console.error(err);
return new Response(err.message, fixCors({ status: err.status ?? 500 }));
};
try {
const auth = request.headers.get("Authorization");
const apiKey = auth?.split(" ")[1];
const assert = (success) => {
if (!success) {
throw new HttpError("The specified HTTP method is not allowed for the requested resource", 400);
}
};
const { pathname } = new URL(request.url);
if(!pathname.endsWith("/chat/completions")){
return new Response("hello")
}
assert(request.method === "POST");
return handleCompletions(await request.json(), apiKey).catch(errHandler);
} catch (err) {
return errHandler(err);
}
}
};
class HttpError extends Error {
constructor(message, status) {
super(message);
this.name = this.constructor.name;
this.status = status;
}
}
const fixCors = ({ headers, status, statusText }) => {
headers = new Headers(headers);
headers.set("Access-Control-Allow-Origin", "*");
return { headers, status, statusText };
};
const handleOPTIONS = async () => {
return new Response(null, {
headers: {
"Access-Control-Allow-Origin": "*",
"Access-Control-Allow-Methods": "*",
"Access-Control-Allow-Headers": "*",
}
});
};
const BASE_URL = "https://generativelanguage.googleapis.com";
const API_VERSION = "v1beta";
// https://github.com/google-gemini/generative-ai-js/blob/cf223ff4a1ee5a2d944c53cddb8976136382bee6/src/requests/request.ts#L71
const API_CLIENT = "genai-js/0.21.0"; // npm view @google/generative-ai version
const makeHeaders = (apiKey, more) => ({
"x-goog-api-client": API_CLIENT,
...(apiKey && { "x-goog-api-key": apiKey }),
...more
});
const DEFAULT_MODEL = "gemini-2.0-flash-exp";
async function handleCompletions (req, apiKey) {
let model = DEFAULT_MODEL;
if(req.model.startsWith("gemini-")) {
model = req.model;
}
const TASK = "generateContent";
let url = `${BASE_URL}/${API_VERSION}/models/${model}:${TASK}`;
const response = await fetch(url, {
method: "POST",
headers: makeHeaders(apiKey, { "Content-Type": "application/json" }),
body: JSON.stringify(await transformRequest(req)), // try
});
let body = response.body;
if (response.ok) {
let id = generateChatcmplId();
body = await response.text();
body = processCompletionsResponse(JSON.parse(body), model, id);
}
return new Response(body, fixCors(response));
}
const harmCategory = [
"HARM_CATEGORY_HATE_SPEECH",
"HARM_CATEGORY_SEXUALLY_EXPLICIT",
"HARM_CATEGORY_DANGEROUS_CONTENT",
"HARM_CATEGORY_HARASSMENT",
"HARM_CATEGORY_CIVIC_INTEGRITY",
];
const safetySettings = harmCategory.map(category => ({
category,
threshold: "BLOCK_NONE",
}));
const fieldsMap = {
stop: "stopSequences",
n: "candidateCount",
max_tokens: "maxOutputTokens",
max_completion_tokens: "maxOutputTokens",
temperature: "temperature",
top_p: "topP",
top_k: "topK",
frequency_penalty: "frequencyPenalty",
presence_penalty: "presencePenalty",
};
const transformConfig = (req) => {
let cfg = {};
for (let key in req) {
const matchedKey = fieldsMap[key];
if (matchedKey) {
cfg[matchedKey] = req[key];
}
}
cfg.responseMimeType = "text/plain";
return cfg;
};
const transformMsg = async ({ role, content }) => {
const parts = [];
if (!Array.isArray(content)) {
parts.push({ text: content });
return { role, parts };
}
for (const item of content) {
switch (item.type) {
case "text":
parts.push({ text: item.text });
break;
case "input_audio":
parts.push({
inlineData: {
mimeType: "audio/" + item.input_audio.format,
data: item.input_audio.data,
}
});
break;
default:
throw new TypeError(`Unknown "content" item type: "${item.type}"`);
}
}
if (content.every(item => item.type === "image_url")) {
parts.push({ text: "" });
}
return { role, parts };
};
const transformMessages = async (messages) => {
if (!messages) { return; }
const contents = [];
let system_instruction;
for (const item of messages) {
if (item.role === "system") {
delete item.role;
system_instruction = await transformMsg(item);
} else {
item.role = item.role === "assistant" ? "model" : "user";
contents.push(await transformMsg(item));
}
}
if (system_instruction && contents.length === 0) {
contents.push({ role: "model", parts: { text: " " } });
}
return { system_instruction, contents };
};
const transformRequest = async (req) => ({
...await transformMessages(req.messages),
safetySettings,
generationConfig: transformConfig(req),
});
const generateChatcmplId = () => {
const characters = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789";
const randomChar = () => characters[Math.floor(Math.random() * characters.length)];
return "chatcmpl-" + Array.from({ length: 29 }, randomChar).join("");
};
const reasonsMap = {
"STOP": "stop",
"MAX_TOKENS": "length",
"SAFETY": "content_filter",
"RECITATION": "content_filter"
};
const SEP = "\n\n|>";
const transformCandidates = (key, cand) => ({
index: cand.index || 0,
[key]: {
role: "assistant",
content: cand.content?.parts.map(p => p.text).join(SEP) },
logprobs: null,
finish_reason: reasonsMap[cand.finishReason] || cand.finishReason,
});
const transformCandidatesMessage = transformCandidates.bind(null, "message");
const transformCandidatesDelta = transformCandidates.bind(null, "delta");
const transformUsage = (data) => ({
completion_tokens: data.candidatesTokenCount,
prompt_tokens: data.promptTokenCount,
total_tokens: data.totalTokenCount
});
const processCompletionsResponse = (data, model, id) => {
return JSON.stringify({
id,
choices: data.candidates.map(transformCandidatesMessage),
created: Math.floor(Date.now()/1000),
model,
object: "chat.completion",
usage: transformUsage(data.usageMetadata),
});
};Binding a Domain
After deployment, there will be a Cloudflare-provided second-level subdomain, but this domain cannot be accessed normally in China, so you need to bind your own domain to achieve proxy-free access.
After deployment, click Back on the left.
Then find Settings -- Domains & Routes, and click Add.
As shown in the figure below, add the domain name that you have already hosted on Cloudflare.
After completion, you can use the domain name to access Gemini.
Using OpenAI SDK to Access Gemini
from openai import OpenAI, APIConnectionError
model = OpenAI(api_key='Gemini\'s API Key', base_url='https://your-custom-domain.com')
response = model.chat.completions.create(
model='gemini-2.0-flash-exp',
messages=[
{
'role': 'user',
'content': 'Who are you?'},
]
)
print(response.choices[0])The following is returned:
Choice(finish_reason='stop', index=0, logprobs=None, message=ChatCompletionMessage(content='I am a large language model, trained by Google.\n', refusal=None, role='assistant', audio=None, function_call=None, tool_calls=None))Using in Other OpenAI Compatible Tools
Find the location where the tool configures OpenAI information, change the API address to the custom domain you added in Cloudflare, change the SK to your Gemini API Key, and fill in gemini-2.0-flash-exp for the model.
Accessing Directly Using Requests
If you don't use the OpenAI SDK, you can also directly use the requests library for access.
import requests
payload={
"model":"gemini-1.5-flash",
"messages":[{
"role":"user",
"content":[{"type":"text","text":"Who are you？"}]
}]
}
res=requests.post('https://xxxx.com/chat/completions',headers={"Authorization":"Bearer your Gemini API Key","Content-Type":"application:/json"},json=payload)
print(res.json())Output is as follows:
Related Resources
- Source code modified from project PublicAffairs/openai-gemini
- GeminiAI Documentation