@helia/verified-fetch/dist/src/utils/response-headers.js

A fetch-like API for obtaining verified & trustless IPFS content on the web

import { InvalidRangeError } from '../errors.js';
/**
 * Implementations may place an upper bound on any TTL received, as noted in Section 8 of [rfc2181].
 * If TTL value is unknown, implementations should not send a Cache-Control
 * No matter if TTL value is known or not, implementations should always send a Last-Modified header with the timestamp of the record resolution.
 *
 * @see https://specs.ipfs.tech/http-gateways/path-gateway/#cache-control-response-header
 */
export function setCacheControlHeader({ ttl, protocol, response }) {
    if (response.headers.has('cache-control')) {
        // don't set the header if it's already set by a plugin
        return;
    }
    let headerValue;
    if (protocol === 'ipfs') {
        headerValue = 'public, max-age=29030400, immutable';
    }
    else if (ttl == null) {
        /**
         * default limit for unknown TTL: "use 5 minute as default fallback when it is not available."
         *
         * @see https://github.com/ipfs/boxo/issues/329#issuecomment-1995236409
         */
        headerValue = 'public, max-age=300';
    }
    else {
        headerValue = `public, max-age=${ttl}`;
    }
    response.headers.set('cache-control', headerValue);
}
/**
 * This function returns the value of the `Content-Range` header for a given range.
 * If you know the total size of the body, pass it as `byteSize`
 *
 * @see https://developer.mozilla.org/en-US/docs/Web/HTTP/Headers/Content-Range
 */
export function getContentRangeHeader({ byteStart, byteEnd, byteSize }) {
    const total = byteSize ?? '*'; // if we don't know the total size, we should use *
    if ((byteEnd ?? 0) >= (byteSize ?? Infinity)) {
        throw new InvalidRangeError('Invalid range: Range-end index is greater than or equal to the size of the file.');
    }
    if ((byteStart ?? 0) >= (byteSize ?? Infinity)) {
        throw new InvalidRangeError('Invalid range: Range-start index is greater than or equal to the size of the file.');
    }
    if (byteStart != null && byteEnd == null) {
        // only byteStart in range
        if (byteSize == null) {
            return `bytes */${total}`;
        }
        return `bytes ${byteStart}-${byteSize - 1}/${byteSize}`;
    }
    if (byteStart == null && byteEnd != null) {
        // only byteEnd in range
        if (byteSize == null) {
            return `bytes */${total}`;
        }
        const end = byteSize - 1;
        const start = end - byteEnd + 1;
        return `bytes ${start}-${end}/${byteSize}`;
    }
    if (byteStart == null && byteEnd == null) {
        // neither are provided, we can't return a valid range.
        return `bytes */${total}`;
    }
    return `bytes ${byteStart}-${byteEnd}/${total}`;
}
/**
 * Sets the `X-Ipfs-Roots` header on the response if it exists.
 *
 * @see https://specs.ipfs.tech/http-gateways/path-gateway/#x-ipfs-roots-response-header
 */
export function setIpfsRoots(response, ipfsRoots) {
    if (ipfsRoots != null) {
        response.headers.set('X-Ipfs-Roots', getIpfsRoots(ipfsRoots));
    }
}
export function getIpfsRoots(ipfsRoots) {
    return ipfsRoots.map(cid => cid.toV1().toString()).join(',');
}
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