feat: Adds new chunk() method as part of example

Author: thecodedrift

package.json

@@ -28,7 +28,7 @@
     "@commitlint/cli": "^19.8.1",
     "@commitlint/config-conventional": "^19.8.1",
     "@extism/js-pdk": "^1.1.1",
-    "@taskless/loader": "0.0.30",
+    "@taskless/loader": "0.0.35",
     "@types/node": "^22.16.0",
     "esbuild": "^0.19.12",
     "husky": "^9.1.7",

pnpm-lock.yaml

@@ -1,8 +1,5 @@
 import { type PluginOutput, type PluginInput } from "@taskless/loader";
 import { type PartialDeep } from "type-fest";
-import { type Pack } from "./__generated__/pack.js";
-
-type PackConfiguration = Pick<Pack, "configuration">;
 
 export const readInput = <
   TContext extends Record<string, unknown> = Record<string, unknown>,
@@ -13,8 +10,7 @@ export const readInput = <
     TContext,
     TRequestBody,
     TResponseBody
-  > &
-    PackConfiguration;
+  >;
 };
 
 export const writeOutput = <

src/helpers.ts

@@ -1,7 +1,17 @@
 // eslint-disable-next-line @typescript-eslint/triple-slash-reference
 /// <reference lib="es2021" />
 
+/*
+Each export here must also be an export inside of your src/index.ts file.
+Extism layers this defintion on top opf your exports in order to create
+a map of function names to memory addresses.
+
+Failure to keep this in sync results in calling functions that do not
+exist, or calling one function and getting the result of another function.
+*/
+
 declare module "main" {
   export function pre(): I32;
   export function post(): I32;
+  export function chunk(): I32;
 }

src/index.d.ts

@@ -4,6 +4,8 @@ import { manifest } from "./manifest.js";
 /** left as an example of passing context into outputs */
 type Context = {
   fromPre: string;
+  currentChunk?: string;
+  lines?: string[];
 };
 
 /**
@@ -37,6 +39,49 @@ export function pre() {
   });
 }
 
+/**
+ * chunk() is called for each chunk of the response body
+ * it's data is base64 encoded
+ */
+export function chunk() {
+  const input = readInput<Context>();
+  const chunk = input.chunk;
+
+  if (!chunk) {
+    return;
+  }
+
+  // take base64 encoded chunk and decode it
+  const decoder = new TextDecoder("utf8");
+  const decodedChunk = decoder.decode(Host.base64ToArrayBuffer(chunk));
+  const current = (input.context.currentChunk ?? "") + decodedChunk;
+
+  // if no newlines, save the current chunk and return
+  if (!current.includes("\n")) {
+    writeOutput<Context>({
+      context: {
+        currentChunk: current,
+      },
+    });
+
+    return;
+  }
+
+  // split the current chunk by newlines, add to the context lines
+  const lines = (input.context.lines ?? [])
+    .concat(current.split("\n"))
+    .map((l) => l.trim())
+    .filter((l) => l.length > 0);
+
+  // save the lines and reset the current chunk
+  writeOutput<Context>({
+    context: {
+      currentChunk: "",
+      lines,
+    },
+  });
+}
+
 /**
  * post() is called after the request is sent to the host
  * and contains the response body
@@ -53,6 +98,7 @@ export function post() {
       // explicit capture from the prior context
       testPostFromPre: input.context.fromPre,
       testResponseData: responseDataC,
+      testChunk: input.context.lines?.join("~~~"),
     },
   });
 }