public struct CacheControl
Represents the HTTP
See Also: Cache-Control docs
The max-stale option can be present with no value, or be present with a number of seconds. By using a struct you can check the nullability of the
maxStalevariable as well as then check the nullability of the
public init(mustRevalidated: Bool = false, noCache: Bool = false, noStore: Bool = false, noTransform: Bool = false, isPublic: Bool = false, isPrivate: Bool = false, proxyRevalidate: Bool = false, onlyIfCached: Bool = false, immutable: Bool = false, maxAge: Int? = nil, sMaxAge: Int? = nil, maxStale: MaxStale? = nil, minFresh: Int? = nil, staleWhileRevalidate: Int? = nil, staleIfError: Int? = nil)
Creates a new
var mustRevalidate: Bool
Indicates that once a resource becomes stale, caches must not use their stale copy without successful validation on the origin server.
var noCache: Bool
Caches must check with the origin server for validation before using the cached copy.
var noStore: Bool
The cache should not store anything about the client request or server response.
var noTransform: Bool
No transformations or conversions should be made to the resource. The Content-Encoding, Content-Range, Content-Type headers must not be modified
by a proxy. A non-transparent proxy or browser feature such as
Google's Light Mode might, for example, convert between image
formats in order to save cache space or to reduce the amount of traffic on a slow link. The
no-transform directive disallows this.
var isPublic: Bool
The response may be cached by any cache, even if the response is normally non-cacheable
var isPrivate: Bool
The response is for a single user and must not be stored by a shared cache. A private cache (like the user's browser cache) may store the response.
var proxyRevalidate: Bool
must-revalidate, but only for shared caches (e.g., proxies). Ignored by private caches.
var onlyIfCached: Bool
Indicates to not retrieve new data. This being the case, the server wishes the client to obtain a response only once and then cache. From this moment the client should keep releasing a cached copy and avoid contacting the origin-server to see if a newer copy exists.
var immutable: Bool
Indicates that the response body will not change over time.
The resource, if unexpired, is unchanged on the server and therefore the client should
not send a conditional revalidation for it (e.g.
If-Modified-Since) to check for updates, even when the user explicitly refreshes
the page. Clients that aren't aware of this extension must ignore them as per the HTTP specification. In Firefox, immutable is only honored on https:// transactions.
For more information, see also this blog post.
var maxAge: Int?
The maximum amount of time a resource is considered fresh. Unlike the
Expires header, this directive is relative to the time of the request.
var sMaxAge: Int?
Overrides max-age or the Expires header, but only for shared caches (e.g., proxies). Ignored by private caches.
var maxStale: MaxStale?
Indicates the client will accept a stale response. An optional value in seconds indicates the upper limit of staleness the client will accept.
var minFresh: Int?
Indicates the client wants a response that will still be fresh for at least the specified number of seconds.
var staleWhileRevalidate: Int?
Indicates the client will accept a stale response, while asynchronously checking in the background for a fresh one. The value indicates how long the client will accept a stale response.
var staleIfError: Int?
Indicates the client will accept a stale response if the check for a fresh one fails. The value indicates how many seconds long the client will accept the stale response after the initial expiration.
public static func parse(_ value: String) -> CacheControl?
public func serialize() -> String
Generates the header string for this instance.