# Genkit Express Plugin
This plugin provides utilities for conveninetly exposing Genkit flows and actions via Express HTTP server as REST APIs.
```ts
import { expressHandler } from '@genkit-ai/express';
import express from 'express';
const simpleFlow = ai.defineFlow('simpleFlow', async (input, { sendChunk }) => {
const { text } = await ai.generate({
model: gemini15Flash,
prompt: input,
onChunk: (c) => sendChunk(c.text),
});
return text;
});
const app = express();
app.use(express.json());
app.post('/simpleFlow', expressHandler(simpleFlow));
app.listen(8080);
```
You can also handle auth using context providers:
```ts
import { UserFacingError } from 'genkit';
import { ContextProvider, RequestData } from 'genkit/context';
const context: ContextProvider<Context> = (req: RequestData) => {
if (req.headers['authorization'] !== 'open sesame') {
throw new UserFacingError('PERMISSION_DENIED', 'not authorized');
}
return {
auth: {
user: 'Ali Baba',
},
};
};
app.post(
'/simpleFlow',
authMiddleware,
expressHandler(simpleFlow, { context })
);
```
Flows and actions exposed using the `expressHandler` function can be accessed using `genkit/beta/client` library:
```ts
import { runFlow, streamFlow } from 'genkit/beta/client';
const result = await runFlow({
url: `http://localhost:${port}/simpleFlow`,
input: 'say hello',
});
console.log(result); // hello
// set auth headers (when using auth policies)
const result = await runFlow({
url: `http://localhost:${port}/simpleFlow`,
headers: {
Authorization: 'open sesame',
},
input: 'say hello',
});
console.log(result); // hello
// and streamed
const result = streamFlow({
url: `http://localhost:${port}/simpleFlow`,
input: 'say hello',
});
for await (const chunk of result.stream) {
console.log(chunk);
}
console.log(await result.output);
```
The sources for this package are in the main [Genkit](https://github.com/firebase/genkit) repo. Please file issues and pull requests against that repo.
Usage information and reference details can be found in [Genkit documentation](https://firebase.google.com/docs/genkit).
License: Apache 2.0