Initial commit

templates/text-generation-fetch.ts

@@ -0,0 +1,124 @@
+/**
+ * Basic Text Generation with Gemini API (Fetch - Cloudflare Workers)
+ *
+ * Demonstrates:
+ * - Direct REST API calls using fetch (no SDK dependencies)
+ * - Perfect for Cloudflare Workers, Deno, Bun, or edge runtimes
+ * - Manual JSON parsing
+ * - Error handling with fetch
+ *
+ * Prerequisites:
+ * - Set GEMINI_API_KEY environment variable (or use env.GEMINI_API_KEY in Workers)
+ */
+
+/**
+ * Example for Cloudflare Workers
+ */
+interface Env {
+  GEMINI_API_KEY: string;
+}
+
+export default {
+  async fetch(request: Request, env: Env): Promise<Response> {
+    try {
+      // Make direct API call to Gemini
+      const response = await fetch(
+        `https://generativelanguage.googleapis.com/v1beta/models/gemini-2.5-flash:generateContent`,
+        {
+          method: 'POST',
+          headers: {
+            'Content-Type': 'application/json',
+            'x-goog-api-key': env.GEMINI_API_KEY,
+          },
+          body: JSON.stringify({
+            contents: [
+              {
+                parts: [
+                  {
+                    text: 'Explain quantum computing in simple terms for a 10-year-old'
+                  }
+                ]
+              }
+            ]
+          }),
+        }
+      );
+
+      // Check for HTTP errors
+      if (!response.ok) {
+        const errorData = await response.json();
+        return new Response(
+          JSON.stringify({
+            error: errorData.error?.message || 'Unknown error',
+            status: response.status
+          }),
+          { status: response.status, headers: { 'Content-Type': 'application/json' } }
+        );
+      }
+
+      // Parse response
+      const data = await response.json();
+
+      // Extract text from response structure
+      const generatedText = data.candidates[0]?.content?.parts[0]?.text;
+      const usageMetadata = data.usageMetadata;
+      const finishReason = data.candidates[0]?.finishReason;
+
+      return new Response(
+        JSON.stringify({
+          text: generatedText,
+          usage: {
+            promptTokens: usageMetadata.promptTokenCount,
+            responseTokens: usageMetadata.candidatesTokenCount,
+            totalTokens: usageMetadata.totalTokenCount
+          },
+          finishReason
+        }),
+        { headers: { 'Content-Type': 'application/json' } }
+      );
+
+    } catch (error: any) {
+      return new Response(
+        JSON.stringify({ error: error.message }),
+        { status: 500, headers: { 'Content-Type': 'application/json' } }
+      );
+    }
+  }
+};
+
+/**
+ * Example for Node.js/Standalone
+ */
+async function mainNodeJS() {
+  const GEMINI_API_KEY = process.env.GEMINI_API_KEY;
+
+  if (!GEMINI_API_KEY) {
+    throw new Error('GEMINI_API_KEY environment variable not set');
+  }
+
+  const response = await fetch(
+    `https://generativelanguage.googleapis.com/v1beta/models/gemini-2.5-flash:generateContent`,
+    {
+      method: 'POST',
+      headers: {
+        'Content-Type': 'application/json',
+        'x-goog-api-key': GEMINI_API_KEY,
+      },
+      body: JSON.stringify({
+        contents: [
+          {
+            parts: [
+              { text: 'Explain quantum computing in simple terms' }
+            ]
+          }
+        ]
+      }),
+    }
+  );
+
+  const data = await response.json();
+  console.log(data.candidates[0].content.parts[0].text);
+}
+
+// Uncomment to run in Node.js
+// mainNodeJS();