* first action! (#1)

node_modules/http-cache-semantics/node4/index.js

@@ -0,0 +1,559 @@
+'use strict';
+// rfc7231 6.1
+
+function _classCallCheck(instance, Constructor) { if (!(instance instanceof Constructor)) { throw new TypeError("Cannot call a class as a function"); } }
+
+var statusCodeCacheableByDefault = [200, 203, 204, 206, 300, 301, 404, 405, 410, 414, 501];
+
+// This implementation does not understand partial responses (206)
+var understoodStatuses = [200, 203, 204, 300, 301, 302, 303, 307, 308, 404, 405, 410, 414, 501];
+
+var hopByHopHeaders = { 'connection': true, 'keep-alive': true, 'proxy-authenticate': true, 'proxy-authorization': true, 'te': true, 'trailer': true, 'transfer-encoding': true, 'upgrade': true };
+var excludedFromRevalidationUpdate = {
+    // Since the old body is reused, it doesn't make sense to change properties of the body
+    'content-length': true, 'content-encoding': true, 'transfer-encoding': true,
+    'content-range': true
+};
+
+function parseCacheControl(header) {
+    var cc = {};
+    if (!header) return cc;
+
+    // TODO: When there is more than one value present for a given directive (e.g., two Expires header fields, multiple Cache-Control: max-age directives),
+    // the directive's value is considered invalid. Caches are encouraged to consider responses that have invalid freshness information to be stale
+    var parts = header.trim().split(/\s*,\s*/); // TODO: lame parsing
+    for (var _iterator = parts, _isArray = Array.isArray(_iterator), _i = 0, _iterator = _isArray ? _iterator : _iterator[Symbol.iterator]();;) {
+        var _ref;
+
+        if (_isArray) {
+            if (_i >= _iterator.length) break;
+            _ref = _iterator[_i++];
+        } else {
+            _i = _iterator.next();
+            if (_i.done) break;
+            _ref = _i.value;
+        }
+
+        var part = _ref;
+
+        var _part$split = part.split(/\s*=\s*/, 2),
+            k = _part$split[0],
+            v = _part$split[1];
+
+        cc[k] = v === undefined ? true : v.replace(/^"|"$/g, ''); // TODO: lame unquoting
+    }
+
+    return cc;
+}
+
+function formatCacheControl(cc) {
+    var parts = [];
+    for (var k in cc) {
+        var v = cc[k];
+        parts.push(v === true ? k : k + '=' + v);
+    }
+    if (!parts.length) {
+        return undefined;
+    }
+    return parts.join(', ');
+}
+
+module.exports = function () {
+    function CachePolicy(req, res) {
+        var _ref2 = arguments.length > 2 && arguments[2] !== undefined ? arguments[2] : {},
+            shared = _ref2.shared,
+            cacheHeuristic = _ref2.cacheHeuristic,
+            immutableMinTimeToLive = _ref2.immutableMinTimeToLive,
+            ignoreCargoCult = _ref2.ignoreCargoCult,
+            _fromObject = _ref2._fromObject;
+
+        _classCallCheck(this, CachePolicy);
+
+        if (_fromObject) {
+            this._fromObject(_fromObject);
+            return;
+        }
+
+        if (!res || !res.headers) {
+            throw Error("Response headers missing");
+        }
+        this._assertRequestHasHeaders(req);
+
+        this._responseTime = this.now();
+        this._isShared = shared !== false;
+        this._cacheHeuristic = undefined !== cacheHeuristic ? cacheHeuristic : 0.1; // 10% matches IE
+        this._immutableMinTtl = undefined !== immutableMinTimeToLive ? immutableMinTimeToLive : 24 * 3600 * 1000;
+
+        this._status = 'status' in res ? res.status : 200;
+        this._resHeaders = res.headers;
+        this._rescc = parseCacheControl(res.headers['cache-control']);
+        this._method = 'method' in req ? req.method : 'GET';
+        this._url = req.url;
+        this._host = req.headers.host;
+        this._noAuthorization = !req.headers.authorization;
+        this._reqHeaders = res.headers.vary ? req.headers : null; // Don't keep all request headers if they won't be used
+        this._reqcc = parseCacheControl(req.headers['cache-control']);
+
+        // Assume that if someone uses legacy, non-standard uncecessary options they don't understand caching,
+        // so there's no point stricly adhering to the blindly copy&pasted directives.
+        if (ignoreCargoCult && "pre-check" in this._rescc && "post-check" in this._rescc) {
+            delete this._rescc['pre-check'];
+            delete this._rescc['post-check'];
+            delete this._rescc['no-cache'];
+            delete this._rescc['no-store'];
+            delete this._rescc['must-revalidate'];
+            this._resHeaders = Object.assign({}, this._resHeaders, { 'cache-control': formatCacheControl(this._rescc) });
+            delete this._resHeaders.expires;
+            delete this._resHeaders.pragma;
+        }
+
+        // When the Cache-Control header field is not present in a request, caches MUST consider the no-cache request pragma-directive
+        // as having the same effect as if "Cache-Control: no-cache" were present (see Section 5.2.1).
+        if (!res.headers['cache-control'] && /no-cache/.test(res.headers.pragma)) {
+            this._rescc['no-cache'] = true;
+        }
+    }
+
+    CachePolicy.prototype.now = function now() {
+        return Date.now();
+    };
+
+    CachePolicy.prototype.storable = function storable() {
+        // The "no-store" request directive indicates that a cache MUST NOT store any part of either this request or any response to it.
+        return !!(!this._reqcc['no-store'] && (
+        // A cache MUST NOT store a response to any request, unless:
+        // The request method is understood by the cache and defined as being cacheable, and
+        'GET' === this._method || 'HEAD' === this._method || 'POST' === this._method && this._hasExplicitExpiration()) &&
+        // the response status code is understood by the cache, and
+        understoodStatuses.indexOf(this._status) !== -1 &&
+        // the "no-store" cache directive does not appear in request or response header fields, and
+        !this._rescc['no-store'] && (
+        // the "private" response directive does not appear in the response, if the cache is shared, and
+        !this._isShared || !this._rescc.private) && (
+        // the Authorization header field does not appear in the request, if the cache is shared,
+        !this._isShared || this._noAuthorization || this._allowsStoringAuthenticated()) && (
+        // the response either:
+
+        // contains an Expires header field, or
+        this._resHeaders.expires ||
+        // contains a max-age response directive, or
+        // contains a s-maxage response directive and the cache is shared, or
+        // contains a public response directive.
+        this._rescc.public || this._rescc['max-age'] || this._rescc['s-maxage'] ||
+        // has a status code that is defined as cacheable by default
+        statusCodeCacheableByDefault.indexOf(this._status) !== -1));
+    };
+
+    CachePolicy.prototype._hasExplicitExpiration = function _hasExplicitExpiration() {
+        // 4.2.1 Calculating Freshness Lifetime
+        return this._isShared && this._rescc['s-maxage'] || this._rescc['max-age'] || this._resHeaders.expires;
+    };
+
+    CachePolicy.prototype._assertRequestHasHeaders = function _assertRequestHasHeaders(req) {
+        if (!req || !req.headers) {
+            throw Error("Request headers missing");
+        }
+    };
+
+    CachePolicy.prototype.satisfiesWithoutRevalidation = function satisfiesWithoutRevalidation(req) {
+        this._assertRequestHasHeaders(req);
+
+        // When presented with a request, a cache MUST NOT reuse a stored response, unless:
+        // the presented request does not contain the no-cache pragma (Section 5.4), nor the no-cache cache directive,
+        // unless the stored response is successfully validated (Section 4.3), and
+        var requestCC = parseCacheControl(req.headers['cache-control']);
+        if (requestCC['no-cache'] || /no-cache/.test(req.headers.pragma)) {
+            return false;
+        }
+
+        if (requestCC['max-age'] && this.age() > requestCC['max-age']) {
+            return false;
+        }
+
+        if (requestCC['min-fresh'] && this.timeToLive() < 1000 * requestCC['min-fresh']) {
+            return false;
+        }
+
+        // the stored response is either:
+        // fresh, or allowed to be served stale
+        if (this.stale()) {
+            var allowsStale = requestCC['max-stale'] && !this._rescc['must-revalidate'] && (true === requestCC['max-stale'] || requestCC['max-stale'] > this.age() - this.maxAge());
+            if (!allowsStale) {
+                return false;
+            }
+        }
+
+        return this._requestMatches(req, false);
+    };
+
+    CachePolicy.prototype._requestMatches = function _requestMatches(req, allowHeadMethod) {
+        // The presented effective request URI and that of the stored response match, and
+        return (!this._url || this._url === req.url) && this._host === req.headers.host && (
+        // the request method associated with the stored response allows it to be used for the presented request, and
+        !req.method || this._method === req.method || allowHeadMethod && 'HEAD' === req.method) &&
+        // selecting header fields nominated by the stored response (if any) match those presented, and
+        this._varyMatches(req);
+    };
+
+    CachePolicy.prototype._allowsStoringAuthenticated = function _allowsStoringAuthenticated() {
+        //  following Cache-Control response directives (Section 5.2.2) have such an effect: must-revalidate, public, and s-maxage.
+        return this._rescc['must-revalidate'] || this._rescc.public || this._rescc['s-maxage'];
+    };
+
+    CachePolicy.prototype._varyMatches = function _varyMatches(req) {
+        if (!this._resHeaders.vary) {
+            return true;
+        }
+
+        // A Vary header field-value of "*" always fails to match
+        if (this._resHeaders.vary === '*') {
+            return false;
+        }
+
+        var fields = this._resHeaders.vary.trim().toLowerCase().split(/\s*,\s*/);
+        for (var _iterator2 = fields, _isArray2 = Array.isArray(_iterator2), _i2 = 0, _iterator2 = _isArray2 ? _iterator2 : _iterator2[Symbol.iterator]();;) {
+            var _ref3;
+
+            if (_isArray2) {
+                if (_i2 >= _iterator2.length) break;
+                _ref3 = _iterator2[_i2++];
+            } else {
+                _i2 = _iterator2.next();
+                if (_i2.done) break;
+                _ref3 = _i2.value;
+            }
+
+            var name = _ref3;
+
+            if (req.headers[name] !== this._reqHeaders[name]) return false;
+        }
+        return true;
+    };
+
+    CachePolicy.prototype._copyWithoutHopByHopHeaders = function _copyWithoutHopByHopHeaders(inHeaders) {
+        var headers = {};
+        for (var name in inHeaders) {
+            if (hopByHopHeaders[name]) continue;
+            headers[name] = inHeaders[name];
+        }
+        // 9.1.  Connection
+        if (inHeaders.connection) {
+            var tokens = inHeaders.connection.trim().split(/\s*,\s*/);
+            for (var _iterator3 = tokens, _isArray3 = Array.isArray(_iterator3), _i3 = 0, _iterator3 = _isArray3 ? _iterator3 : _iterator3[Symbol.iterator]();;) {
+                var _ref4;
+
+                if (_isArray3) {
+                    if (_i3 >= _iterator3.length) break;
+                    _ref4 = _iterator3[_i3++];
+                } else {
+                    _i3 = _iterator3.next();
+                    if (_i3.done) break;
+                    _ref4 = _i3.value;
+                }
+
+                var _name = _ref4;
+
+                delete headers[_name];
+            }
+        }
+        if (headers.warning) {
+            var warnings = headers.warning.split(/,/).filter(function (warning) {
+                return !/^\s*1[0-9][0-9]/.test(warning);
+            });
+            if (!warnings.length) {
+                delete headers.warning;
+            } else {
+                headers.warning = warnings.join(',').trim();
+            }
+        }
+        return headers;
+    };
+
+    CachePolicy.prototype.responseHeaders = function responseHeaders() {
+        var headers = this._copyWithoutHopByHopHeaders(this._resHeaders);
+        var age = this.age();
+
+        // A cache SHOULD generate 113 warning if it heuristically chose a freshness
+        // lifetime greater than 24 hours and the response's age is greater than 24 hours.
+        if (age > 3600 * 24 && !this._hasExplicitExpiration() && this.maxAge() > 3600 * 24) {
+            headers.warning = (headers.warning ? `${headers.warning}, ` : '') + '113 - "rfc7234 5.5.4"';
+        }
+        headers.age = `${Math.round(age)}`;
+        return headers;
+    };
+
+    /**
+     * Value of the Date response header or current time if Date was demed invalid
+     * @return timestamp
+     */
+
+
+    CachePolicy.prototype.date = function date() {
+        var dateValue = Date.parse(this._resHeaders.date);
+        var maxClockDrift = 8 * 3600 * 1000;
+        if (Number.isNaN(dateValue) || dateValue < this._responseTime - maxClockDrift || dateValue > this._responseTime + maxClockDrift) {
+            return this._responseTime;
+        }
+        return dateValue;
+    };
+
+    /**
+     * Value of the Age header, in seconds, updated for the current time.
+     * May be fractional.
+     *
+     * @return Number
+     */
+
+
+    CachePolicy.prototype.age = function age() {
+        var age = Math.max(0, (this._responseTime - this.date()) / 1000);
+        if (this._resHeaders.age) {
+            var ageValue = this._ageValue();
+            if (ageValue > age) age = ageValue;
+        }
+
+        var residentTime = (this.now() - this._responseTime) / 1000;
+        return age + residentTime;
+    };
+
+    CachePolicy.prototype._ageValue = function _ageValue() {
+        var ageValue = parseInt(this._resHeaders.age);
+        return isFinite(ageValue) ? ageValue : 0;
+    };
+
+    /**
+     * Value of applicable max-age (or heuristic equivalent) in seconds. This counts since response's `Date`.
+     *
+     * For an up-to-date value, see `timeToLive()`.
+     *
+     * @return Number
+     */
+
+
+    CachePolicy.prototype.maxAge = function maxAge() {
+        if (!this.storable() || this._rescc['no-cache']) {
+            return 0;
+        }
+
+        // Shared responses with cookies are cacheable according to the RFC, but IMHO it'd be unwise to do so by default
+        // so this implementation requires explicit opt-in via public header
+        if (this._isShared && this._resHeaders['set-cookie'] && !this._rescc.public && !this._rescc.immutable) {
+            return 0;
+        }
+
+        if (this._resHeaders.vary === '*') {
+            return 0;
+        }
+
+        if (this._isShared) {
+            if (this._rescc['proxy-revalidate']) {
+                return 0;
+            }
+            // if a response includes the s-maxage directive, a shared cache recipient MUST ignore the Expires field.
+            if (this._rescc['s-maxage']) {
+                return parseInt(this._rescc['s-maxage'], 10);
+            }
+        }
+
+        // If a response includes a Cache-Control field with the max-age directive, a recipient MUST ignore the Expires field.
+        if (this._rescc['max-age']) {
+            return parseInt(this._rescc['max-age'], 10);
+        }
+
+        var defaultMinTtl = this._rescc.immutable ? this._immutableMinTtl : 0;
+
+        var dateValue = this.date();
+        if (this._resHeaders.expires) {
+            var expires = Date.parse(this._resHeaders.expires);
+            // A cache recipient MUST interpret invalid date formats, especially the value "0", as representing a time in the past (i.e., "already expired").
+            if (Number.isNaN(expires) || expires < dateValue) {
+                return 0;
+            }
+            return Math.max(defaultMinTtl, (expires - dateValue) / 1000);
+        }
+
+        if (this._resHeaders['last-modified']) {
+            var lastModified = Date.parse(this._resHeaders['last-modified']);
+            if (isFinite(lastModified) && dateValue > lastModified) {
+                return Math.max(defaultMinTtl, (dateValue - lastModified) / 1000 * this._cacheHeuristic);
+            }
+        }
+
+        return defaultMinTtl;
+    };
+
+    CachePolicy.prototype.timeToLive = function timeToLive() {
+        return Math.max(0, this.maxAge() - this.age()) * 1000;
+    };
+
+    CachePolicy.prototype.stale = function stale() {
+        return this.maxAge() <= this.age();
+    };
+
+    CachePolicy.fromObject = function fromObject(obj) {
+        return new this(undefined, undefined, { _fromObject: obj });
+    };
+
+    CachePolicy.prototype._fromObject = function _fromObject(obj) {
+        if (this._responseTime) throw Error("Reinitialized");
+        if (!obj || obj.v !== 1) throw Error("Invalid serialization");
+
+        this._responseTime = obj.t;
+        this._isShared = obj.sh;
+        this._cacheHeuristic = obj.ch;
+        this._immutableMinTtl = obj.imm !== undefined ? obj.imm : 24 * 3600 * 1000;
+        this._status = obj.st;
+        this._resHeaders = obj.resh;
+        this._rescc = obj.rescc;
+        this._method = obj.m;
+        this._url = obj.u;
+        this._host = obj.h;
+        this._noAuthorization = obj.a;
+        this._reqHeaders = obj.reqh;
+        this._reqcc = obj.reqcc;
+    };
+
+    CachePolicy.prototype.toObject = function toObject() {
+        return {
+            v: 1,
+            t: this._responseTime,
+            sh: this._isShared,
+            ch: this._cacheHeuristic,
+            imm: this._immutableMinTtl,
+            st: this._status,
+            resh: this._resHeaders,
+            rescc: this._rescc,
+            m: this._method,
+            u: this._url,
+            h: this._host,
+            a: this._noAuthorization,
+            reqh: this._reqHeaders,
+            reqcc: this._reqcc
+        };
+    };
+
+    /**
+     * Headers for sending to the origin server to revalidate stale response.
+     * Allows server to return 304 to allow reuse of the previous response.
+     *
+     * Hop by hop headers are always stripped.
+     * Revalidation headers may be added or removed, depending on request.
+     */
+
+
+    CachePolicy.prototype.revalidationHeaders = function revalidationHeaders(incomingReq) {
+        this._assertRequestHasHeaders(incomingReq);
+        var headers = this._copyWithoutHopByHopHeaders(incomingReq.headers);
+
+        // This implementation does not understand range requests
+        delete headers['if-range'];
+
+        if (!this._requestMatches(incomingReq, true) || !this.storable()) {
+            // revalidation allowed via HEAD
+            // not for the same resource, or wasn't allowed to be cached anyway
+            delete headers['if-none-match'];
+            delete headers['if-modified-since'];
+            return headers;
+        }
+
+        /* MUST send that entity-tag in any cache validation request (using If-Match or If-None-Match) if an entity-tag has been provided by the origin server. */
+        if (this._resHeaders.etag) {
+            headers['if-none-match'] = headers['if-none-match'] ? `${headers['if-none-match']}, ${this._resHeaders.etag}` : this._resHeaders.etag;
+        }
+
+        // Clients MAY issue simple (non-subrange) GET requests with either weak validators or strong validators. Clients MUST NOT use weak validators in other forms of request.
+        var forbidsWeakValidators = headers['accept-ranges'] || headers['if-match'] || headers['if-unmodified-since'] || this._method && this._method != 'GET';
+
+        /* SHOULD send the Last-Modified value in non-subrange cache validation requests (using If-Modified-Since) if only a Last-Modified value has been provided by the origin server.
+        Note: This implementation does not understand partial responses (206) */
+        if (forbidsWeakValidators) {
+            delete headers['if-modified-since'];
+
+            if (headers['if-none-match']) {
+                var etags = headers['if-none-match'].split(/,/).filter(function (etag) {
+                    return !/^\s*W\//.test(etag);
+                });
+                if (!etags.length) {
+                    delete headers['if-none-match'];
+                } else {
+                    headers['if-none-match'] = etags.join(',').trim();
+                }
+            }
+        } else if (this._resHeaders['last-modified'] && !headers['if-modified-since']) {
+            headers['if-modified-since'] = this._resHeaders['last-modified'];
+        }
+
+        return headers;
+    };
+
+    /**
+     * Creates new CachePolicy with information combined from the previews response,
+     * and the new revalidation response.
+     *
+     * Returns {policy, modified} where modified is a boolean indicating
+     * whether the response body has been modified, and old cached body can't be used.
+     *
+     * @return {Object} {policy: CachePolicy, modified: Boolean}
+     */
+
+
+    CachePolicy.prototype.revalidatedPolicy = function revalidatedPolicy(request, response) {
+        this._assertRequestHasHeaders(request);
+        if (!response || !response.headers) {
+            throw Error("Response headers missing");
+        }
+
+        // These aren't going to be supported exactly, since one CachePolicy object
+        // doesn't know about all the other cached objects.
+        var matches = false;
+        if (response.status !== undefined && response.status != 304) {
+            matches = false;
+        } else if (response.headers.etag && !/^\s*W\//.test(response.headers.etag)) {
+            // "All of the stored responses with the same strong validator are selected.
+            // If none of the stored responses contain the same strong validator,
+            // then the cache MUST NOT use the new response to update any stored responses."
+            matches = this._resHeaders.etag && this._resHeaders.etag.replace(/^\s*W\//, '') === response.headers.etag;
+        } else if (this._resHeaders.etag && response.headers.etag) {
+            // "If the new response contains a weak validator and that validator corresponds
+            // to one of the cache's stored responses,
+            // then the most recent of those matching stored responses is selected for update."
+            matches = this._resHeaders.etag.replace(/^\s*W\//, '') === response.headers.etag.replace(/^\s*W\//, '');
+        } else if (this._resHeaders['last-modified']) {
+            matches = this._resHeaders['last-modified'] === response.headers['last-modified'];
+        } else {
+            // If the new response does not include any form of validator (such as in the case where
+            // a client generates an If-Modified-Since request from a source other than the Last-Modified
+            // response header field), and there is only one stored response, and that stored response also
+            // lacks a validator, then that stored response is selected for update.
+            if (!this._resHeaders.etag && !this._resHeaders['last-modified'] && !response.headers.etag && !response.headers['last-modified']) {
+                matches = true;
+            }
+        }
+
+        if (!matches) {
+            return {
+                policy: new this.constructor(request, response),
+                modified: true
+            };
+        }
+
+        // use other header fields provided in the 304 (Not Modified) response to replace all instances
+        // of the corresponding header fields in the stored response.
+        var headers = {};
+        for (var k in this._resHeaders) {
+            headers[k] = k in response.headers && !excludedFromRevalidationUpdate[k] ? response.headers[k] : this._resHeaders[k];
+        }
+
+        var newResponse = Object.assign({}, response, {
+            status: this._status,
+            method: this._method,
+            headers
+        });
+        return {
+            policy: new this.constructor(request, newResponse),
+            modified: false
+        };
+    };
+
+    return CachePolicy;
+}();