sabercat

README

sabercat is an implementation of net/http.FileSystem to serve files directly from MongoDB's GridFS.

Directory listing has not been implemented due to security concerns in our particular use case.

---

Version 1.4.12

Documentation

Index

• Constants
• type Cache
  • func NewCache(d time.Duration, handler http.Handler) *Cache
  • func (ch *Cache) ServeHTTP(w http.ResponseWriter, r *http.Request)
• type GridDir
  • func (gd GridDir) Open(filename string) (http.File, error)

Constants

const (
	// Per default items up to 20 Mibibytes in size will be cached
	DEFAULT_MAX_CACHEABLE_SIZE = 20 * (1 << (10 * 2))
)

Types

type Cache

type Cache struct {
	// Time for which a answer is held im memory. A TTL <= 0
	// makes the Cache pass all requests directly to the handler.
	TTL time.Duration
	// Handler, whose responses are supposed to be cached
	Handler http.Handler
	// Maximum number of bytes, with which an response is eligible
	// for caching (default: 20MiB)
	MaxCacheableSize int64
	// contains filtered or unexported fields
}

Cache is a `net/http.Handler`, which uses `net/http/httptest.ResponseRecorder` to record and recall the responses of the wrapped handler from memory if the same URL is requested again. The `net/http.Request.URL.Path` is used as the caching key.

func NewCache

func NewCache(d time.Duration, handler http.Handler) *Cache

NewCache returns a new Cache, which records the responses of the given handler for the given duration.

func (*Cache) ServeHTTP

func (ch *Cache) ServeHTTP(w http.ResponseWriter, r *http.Request)

type GridDir

type GridDir struct {
	GridFS *mgo.GridFS
	// If true, the leading slash will be stripped from requests
	StripSlash bool
}

GridDir implements net/http.FileSystem to serve contents directly from MongoDB's GridFS.

To serve all files from a database containing a GridFS called `fs` via http:

session, err := mgo.Dial("mongodb://localhost/database")
if err != nil {
    log.Fatalf("Could not connect to mongodb: %s", err)
}
gfs := session.DB("").GridFS("fs")
http.Handle("/", http.FileServer(sabercat.GridDir{gfs})

Directory listing has not been implemented.

func (GridDir) Open

func (gd GridDir) Open(filename string) (http.File, error)

Tries to open a file with the corresponding GridFS path. If the connection to the server broke, a single retry is issued.