94 lines
3.3 KiB
Go
94 lines
3.3 KiB
Go
package header
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import (
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"strconv"
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"github.com/gin-gonic/gin"
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)
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const (
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// The CacheControl request and response header field contains directives (instructions)
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// that control caching in browsers and shared caches (e.g. proxies, CDNs).
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// See: https://developer.mozilla.org/en-US/docs/Web/HTTP/Headers/Cache-Control
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CacheControl = "Cache-Control"
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// CacheControlDefault indicates that the response remains valid for 604800 seconds (7 days) after it
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// has been generated. Note that max-age is not the time that has elapsed since the response was received,
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// but the time that has elapsed since the response was created on the origin server.
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CacheControlDefault = "max-age=604800"
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// CacheControlNoStore indicates that caches of any kind (private or shared) should not store the response.
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CacheControlNoStore = "no-store"
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// CacheControlNoCache indicates that the response can be stored in caches, but must be validated with
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// the origin server before each reuse, even when the cache is not connected to the origin server.
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CacheControlNoCache = "no-cache"
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// CacheControlPublic indicates that the response can be stored in a shared cache.
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// Responses to requests with Authorization header fields must not be stored in a shared cache;
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// however, the public directive causes such responses to be stored in a shared cache.
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CacheControlPublic = "public"
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// CacheControlPrivate indicates that the response can only be stored in a private cache (e.g. browsers).
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// You should add the private directive for personalized content, especially for responses sent after login.
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CacheControlPrivate = "private"
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// CacheControlImmutable indicates that the response will not be updated while it's fresh.
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CacheControlImmutable = "immutable"
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)
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// CacheControl defaults.
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var (
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CacheControlPublicDefault = CacheControlPublic + ", " + CacheControlDefault // public, max-age=604800
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CacheControlPrivateDefault = CacheControlPrivate + ", " + CacheControlDefault // private, max-age=604800
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)
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// CacheControlMaxAge returns a CacheControl header value based on the specified
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// maxAge time in seconds or the defaults if maxAge is not a positive number.
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func CacheControlMaxAge(maxAge int, public bool) string {
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if maxAge < 0 {
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return CacheControlNoCache
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} else if maxAge > 31536000 {
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maxAge = 31536000
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}
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switch {
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case maxAge > 0 && public:
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return "public, max-age=" + strconv.Itoa(maxAge)
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case maxAge > 0:
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return "private, max-age=" + strconv.Itoa(maxAge)
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case public:
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return CacheControlPublicDefault
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default:
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return CacheControlPrivateDefault
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}
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}
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// SetCacheControl adds a CacheControl header to the response based on the specified parameters.
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// If maxAge is 0, the defaults will be used.
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func SetCacheControl(c *gin.Context, maxAge int, public bool) {
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if c == nil {
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return
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} else if c.Writer == nil {
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return
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}
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c.Header(CacheControl, CacheControlMaxAge(maxAge, public))
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}
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// SetCacheControlImmutable adds a CacheControl header to the response based on the specified parameters
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// and with the immutable directive set. If maxAge is 0, the defaults will be used.
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func SetCacheControlImmutable(c *gin.Context, maxAge int, public bool) {
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if c == nil {
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return
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} else if c.Writer == nil {
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return
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}
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if maxAge < 0 {
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c.Header(CacheControl, CacheControlNoCache)
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return
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}
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c.Header(CacheControl, CacheControlMaxAge(maxAge, public)+", "+CacheControlImmutable)
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}
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