Request Body & Streaming

Volten features on-demand body parsing and streaming:

await ctx.body(type?: 'json' | 'text')

Parses the incoming request body on demand. Caches the result on the context so multiple calls return the same data without re-reading the stream:

app.post("/api/data", async (ctx) => {
  // Parse as JSON
  const json = await ctx.body();

  // Or parse as raw string
  // const text = await ctx.body('text');

  return ctx.json({ received: json });
});

ctx.bodyStream

Exposes the request payload as a standard Web ReadableStream<Uint8Array>:

import { Writable } from "stream";
import fs from "fs";

app.post("/upload-stream", async (ctx) => {
  const fileStream = fs.createWriteStream("./uploads/file.bin");

  // Pipe Web ReadableStream to Node WritableStream
  await ctx.bodyStream.pipeTo(Writable.toWeb(fileStream));

  return ctx.send("Stream uploaded successfully");
});

ctx.multipart()

An asynchronous generator for streaming multipart file uploads without buffering the entire payload into RAM:

app.post("/upload", async (ctx) => {
  for await (const part of ctx.multipart()) {
    if (part.isFile) {
      console.log(`Uploading file: ${part.filename}`);
      await part.save(`./uploads/${part.filename}`);
    } else {
      console.log(`Field ${part.name}: ${part.value}`);
    }
  }

  return ctx.json({ success: true });
});

For complete details on uploads and parsing, see the Body Parsing & Uploads Guide.

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