70 lines
1.8 KiB
TypeScript
70 lines
1.8 KiB
TypeScript
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/**
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* Request body size limiter.
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*
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* Checks the Content-Length header against a configurable maximum.
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* Returns a 413 Payload Too Large response when the body exceeds the limit.
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* Requests without a Content-Length header are passed through since
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* the body size cannot be determined upfront with streaming.
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*/
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const DEFAULT_MAX_BODY_SIZE = 1_048_576; // 1 MB
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let maxBodySize = DEFAULT_MAX_BODY_SIZE;
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/**
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* Check whether the request body exceeds the configured size limit.
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*
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* Returns a 413 Response if the Content-Length header indicates the body
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* is too large. Returns `null` if the body is acceptable or if the size
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* cannot be determined (no Content-Length header).
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*/
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export function checkBodySize(request: Request): Response | null {
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const contentType = request.headers.get("content-length");
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if (contentType === null) {
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// Cannot determine size upfront — pass through (streaming body).
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return null;
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}
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const contentLength = Number.parseInt(contentType, 10);
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if (Number.isNaN(contentLength) || contentLength < 0) {
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// Malformed Content-Length — pass through and let the server handle it.
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return null;
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}
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if (contentLength > maxBodySize) {
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return new Response(
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JSON.stringify({
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error: "Payload Too Large",
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message: `Request body exceeds the maximum allowed size of ${maxBodySize} bytes`,
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maxSizeBytes: maxBodySize,
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}),
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{
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status: 413,
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headers: {
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"Content-Type": "application/json",
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},
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},
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);
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}
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return null;
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}
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/**
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* Update the maximum allowed body size.
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*/
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export function setMaxBodySize(bytes: number): void {
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if (bytes < 0) {
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throw new Error("maxBodySize must be a non-negative number");
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}
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maxBodySize = bytes;
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}
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/**
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* Get the current maximum allowed body size in bytes.
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*/
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export function getMaxBodySize(): number {
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return maxBodySize;
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}
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