README
¶
httpcache
Package httpcache provides a http.RoundTripper implementation that works as a mostly RFC 7234 compliant cache for http responses. This incarnation of the library is an active fork of github.com/gregjones/httpcache which is unmaintained.
It is only suitable for use as a 'private' cache (i.e. for a web-browser or an API-client and not for a shared proxy).
Cache Backends
- The built-in 'memory' cache stores responses in an in-memory map. -
github.com/bitcomplete/httpcache/diskcacheprovides a filesystem-backed cache using the diskv library. -github.com/bitcomplete/httpcache/memcacheprovides memcache implementations, for both App Engine and 'normal' memcache servers. -sourcegraph.com/sourcegraph/s3cacheuses Amazon S3 for storage. -github.com/bitcomplete/httpcache/leveldbcacheprovides a filesystem-backed cache using leveldb. -github.com/die-net/lrucacheprovides an in-memory cache that will evict least-recently used entries. -github.com/die-net/lrucache/twotierallows caches to be combined, for example to use lrucache above with a persistent disk-cache. -github.com/birkelund/boltdbcacheprovides a BoltDB implementation (based on the bbolt fork).
If you implement any other backend and wish it to be linked here, please send a PR editing this file.
License
Documentation
¶
Overview ¶
Package httpcache provides a http.RoundTripper implementation that works as a mostly RFC-compliant cache for http responses.
It is only suitable for use as a 'private' cache (i.e. for a web-browser or an API-client and not for a shared proxy).
Index ¶
Constants ¶
const (
// XFromCache is the header added to responses that are returned from the cache
XFromCache = "X-From-Cache"
)
Variables ¶
var DefaultKeyFunc = func(req *http.Request) string { if req.Method == http.MethodGet { return req.URL.String() } else { return req.Method + " " + req.URL.String() } }
DefaultKeyFunc returns the cache key for req
var ErrNoDateHeader = errors.New("no Date header")
ErrNoDateHeader indicates that the HTTP headers contained no Date header.
Functions ¶
Types ¶
type Cache ¶
type Cache interface {
// Get returns the []byte representation of a cached response and a bool
// set to true if the value isn't empty
Get(ctx context.Context, key string) (responseBytes []byte, ok bool)
// Set stores the []byte representation of a response against a key
Set(ctx context.Context, key string, responseBytes []byte)
// Delete removes the value associated with the key
Delete(ctx context.Context, key string)
}
A Cache interface is used by the Transport to store and retrieve responses.
type MemoryCache ¶
type MemoryCache struct {
// contains filtered or unexported fields
}
MemoryCache is an implemtation of Cache that stores responses in an in-memory map.
func NewMemoryCache ¶
func NewMemoryCache() *MemoryCache
NewMemoryCache returns a new Cache that will store items in an in-memory map
func (*MemoryCache) Delete ¶
func (c *MemoryCache) Delete(ctx context.Context, key string)
Delete removes key from the cache
type Transport ¶
type Transport struct {
// The RoundTripper interface actually used to make requests
// If nil, http.DefaultTransport is used
Transport http.RoundTripper
Cache Cache
// If true, responses returned from the cache will be given an extra header, X-From-Cache
MarkCachedResponses bool
// A function to generate a cache key for the given request
KeyFunc KeyFunc
}
Transport is an implementation of http.RoundTripper that will return values from a cache where possible (avoiding a network request) and will additionally add validators (etag/if-modified-since) to repeated requests allowing servers to return 304 / Not Modified
func NewMemoryCacheTransport ¶
func NewMemoryCacheTransport(opts ...TransportOpt) *Transport
NewMemoryCacheTransport returns a new Transport using the in-memory cache implementation
func NewTransport ¶
func NewTransport(c Cache, opts ...TransportOpt) *Transport
NewTransport returns a new Transport with the provided Cache and options. If KeyFunc is not specified in opts then DefaultKeyFunc is used.
func (*Transport) RoundTrip ¶
RoundTrip takes a Request and returns a Response
If there is a fresh Response already in cache, then it will be returned without connecting to the server.
If there is a stale Response, then any validators it contains will be set on the new request to give the server a chance to respond with NotModified. If this happens, then the cached Response will be returned.
type TransportOpt ¶
type TransportOpt func(t *Transport)
TransportOpt is a configuration option for creating a new Transport
func KeyFuncOpt ¶
func KeyFuncOpt(keyFunc KeyFunc) TransportOpt
KeyFuncOpt configures a transport by setting its KeyFunc to the one given
func MarkCachedResponsesOpt ¶
func MarkCachedResponsesOpt(markCachedResponses bool) TransportOpt
MarkCachedResponsesOpt configures a transport by setting MarkCachedResponses to true
Source Files
Directories
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| Path | Synopsis |
|---|---|
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Package diskcache provides an implementation of httpcache.Cache that uses the diskv package to supplement an in-memory map with persistent storage
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Package diskcache provides an implementation of httpcache.Cache that uses the diskv package to supplement an in-memory map with persistent storage |
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Package leveldbcache provides an implementation of httpcache.Cache that uses github.com/syndtr/goleveldb/leveldb
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Package leveldbcache provides an implementation of httpcache.Cache that uses github.com/syndtr/goleveldb/leveldb |
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Package memcache provides an implementation of httpcache.Cache that uses gomemcache to store cached responses.
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Package memcache provides an implementation of httpcache.Cache that uses gomemcache to store cached responses. |
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Package redis provides a redis interface for http caching.
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Package redis provides a redis interface for http caching. |