46 lines
1.2 KiB
TypeScript
46 lines
1.2 KiB
TypeScript
interface ReadableResponse {
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headers: { get: (name: string) => string | null };
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body: {
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getReader: () => {
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read: () => Promise<{ done: boolean; value?: Uint8Array }>;
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cancel: () => Promise<void>;
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};
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} | null;
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}
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export async function readBoundedJsonResponseAsync(
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response: ReadableResponse,
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maxBytes: number,
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label = "Response",
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): Promise<unknown> {
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const declaredLength = Number(response.headers.get("content-length"));
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if (Number.isFinite(declaredLength) && declaredLength > maxBytes) {
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throw new Error(`${label} exceeds ${maxBytes} bytes`);
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}
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if (!response.body) return null;
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const reader = response.body.getReader();
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const chunks: Uint8Array[] = [];
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let byteLength = 0;
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for (;;) {
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const { done, value } = await reader.read();
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if (done) break;
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if (!value) continue;
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byteLength += value.byteLength;
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if (byteLength > maxBytes) {
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await reader.cancel();
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throw new Error(`${label} exceeds ${maxBytes} bytes`);
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}
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chunks.push(value);
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}
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const body = new Uint8Array(byteLength);
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let offset = 0;
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for (const chunk of chunks) {
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body.set(chunk, offset);
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offset += chunk.byteLength;
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}
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return JSON.parse(new TextDecoder().decode(body)) as unknown;
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}
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