github.com/sniperkit/cacher

sniperkit-httpcache

=========

[WIP]

Summary

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).

Cache Backends

Defaults

• The built-in 'memory' cache stores responses in an in-memory map.

Memory

• plugins/lru provides an in-memory cache that will evict least-recently used entries. (original: github.com/die-net/lrucache)
• plugins/lru/twotier allows caches to be combined, for example to use lrucache above with a persistent disk-cache. (original: github.com/die-net/lrucache/twotier)

File System - Storage

Local

• github.com/gregjones/httpcache/diskcache provides a filesystem-backed cache using the diskv library.
• plugins/bbolt
• plugins/boltdb-gzip
• plugins/boltdb-ttl
• plugins/storm
• plugins/leveldb provides a filesystem-backed cache using leveldb.

Cloud

• plugins/azurestorage uses Azure Storage service. (original: github.com/PaulARoy/azurestoragecache)
• plugins/gcs uses Google cloud service engine. (original: github.com/PaulARoy/azurestoragecache)
• plugins/diskv/s3 uses Amazon S3 for storage. (original: github.com/sourcegraph/s3cache)

KV

• plugins/etcd/v2 provides etcd api v2 implentation
• plugins/etcd/v3 provides etcd api v3 implentation
• plugins/e3ch provides etcd api v3 implentation with hierarchy
• plugins/memcache provides memcache implementations, for both App Engine and 'normal' memcache servers. (Original: memcache)

RDB

• plugins/gorm provides gorm implementations, mainly for debugging and development

Getting started

Below is a basic example of usage.

func httpCacheExample() {
    numOfRequests := 0
    ts := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
        w.Header().Set("Cache-Control", fmt.Sprintf("private, max-age=10"))
        if numOfRequests == 0 {
            w.Write([]byte("Hello!"))
        } else {
            w.Write([]byte("Goodbye!"))
        }
        numOfRequests++
    }))

    httpClient := &http.Client{
        Transport: httpcache.NewMemoryCacheTransport(),
    }
    makeRequest(ts, httpClient) // "Hello!"

    // The second request is under max-age, so the cache is used rather than hitting the server
    makeRequest(ts, httpClient) // "Hello!"

    // Sleep so the max-age is passed
    time.Sleep(time.Second * 11)

    makeRequest(ts, httpClient) // "Goodbye!"
}

func makeRequest(ts *httptest.Server, httpClient *http.Client) {
    resp, _ := httpClient.Get(ts.URL)
    var buf bytes.Buffer
    io.Copy(&buf, resp.Body)
    println(buf.String())
}

License

• MIT License