158 lines
3.9 KiB
TypeScript
158 lines
3.9 KiB
TypeScript
/**
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* Gemini Embeddings with Fetch (Cloudflare Workers)
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*
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* Demonstrates embedding generation using fetch API instead of SDK.
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* Perfect for Cloudflare Workers and edge environments.
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*
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* Setup:
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* 1. Add GEMINI_API_KEY to wrangler.jsonc secrets
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* 2. npx wrangler secret put GEMINI_API_KEY
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* 3. Deploy: npx wrangler deploy
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*
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* Usage:
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* GET /?text=your+text+here
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*/
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interface Env {
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GEMINI_API_KEY: string;
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}
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interface EmbeddingRequest {
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content: {
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parts: Array<{ text: string }>;
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};
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taskType?: string;
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outputDimensionality?: number;
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}
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interface EmbeddingResponse {
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embedding: {
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values: number[];
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};
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}
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export default {
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async fetch(request: Request, env: Env): Promise<Response> {
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// CORS headers for browser access
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const corsHeaders = {
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'Access-Control-Allow-Origin': '*',
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'Access-Control-Allow-Methods': 'GET, POST, OPTIONS',
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'Access-Control-Allow-Headers': 'Content-Type'
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};
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// Handle CORS preflight
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if (request.method === 'OPTIONS') {
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return new Response(null, { headers: corsHeaders });
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}
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try {
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// Get text from query param or request body
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const url = new URL(request.url);
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let text: string;
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if (request.method === 'POST') {
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const body = await request.json<{ text: string }>();
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text = body.text;
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} else {
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text = url.searchParams.get('text') || 'What is the meaning of life?';
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}
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console.log(`Generating embedding for: "${text}"`);
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// Prepare request
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const embeddingRequest: EmbeddingRequest = {
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content: {
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parts: [{ text }]
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},
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taskType: 'SEMANTIC_SIMILARITY',
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outputDimensionality: 768
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};
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// Call Gemini API
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const response = await fetch(
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'https://generativelanguage.googleapis.com/v1beta/models/gemini-embedding-001:embedContent',
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{
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method: 'POST',
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headers: {
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'x-goog-api-key': env.GEMINI_API_KEY,
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'Content-Type': 'application/json'
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},
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body: JSON.stringify(embeddingRequest)
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}
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);
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if (!response.ok) {
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const error = await response.text();
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throw new Error(`Gemini API error: ${response.status} - ${error}`);
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}
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const data = await response.json<EmbeddingResponse>();
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const embedding = data.embedding.values;
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// Calculate vector magnitude
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const magnitude = Math.sqrt(
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embedding.reduce((sum, v) => sum + v * v, 0)
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);
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// Return formatted response
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return new Response(JSON.stringify({
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success: true,
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text,
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embedding: {
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dimensions: embedding.length,
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magnitude: magnitude.toFixed(4),
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firstValues: embedding.slice(0, 10).map(v => parseFloat(v.toFixed(4))),
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fullVector: embedding
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}
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}, null, 2), {
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headers: {
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'Content-Type': 'application/json',
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...corsHeaders
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}
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});
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} catch (error: any) {
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console.error('Error:', error.message);
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return new Response(JSON.stringify({
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success: false,
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error: error.message,
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hint: error.message.includes('401')
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? 'Check GEMINI_API_KEY secret is set'
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: error.message.includes('429')
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? 'Rate limit exceeded (Free tier: 100 RPM)'
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: 'Check error message for details'
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}, null, 2), {
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status: 500,
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headers: {
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'Content-Type': 'application/json',
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...corsHeaders
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}
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});
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}
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}
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};
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/**
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* Example wrangler.jsonc configuration:
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*
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* {
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* "name": "gemini-embeddings-worker",
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* "main": "src/index.ts",
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* "compatibility_date": "2025-10-25",
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* "vars": {
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* "ENVIRONMENT": "production"
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* }
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* }
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*
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* Set secret:
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* npx wrangler secret put GEMINI_API_KEY
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*
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* Test locally:
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* npx wrangler dev
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* curl "http://localhost:8787/?text=Hello+world"
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*
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* Deploy:
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* npx wrangler deploy
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*/
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