imagecache

package

v0.2.0 Latest Latest Go to latest Published: Oct 12, 2026 License: Apache-2.0 Imports: 16 Imported by: 0

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Valid go.mod file
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Repository

github.com/godwit-email/godwit

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Documentation ¶

Overview ¶

Package imagecache is the privacy proxy's store for remote mail images: a directory of files named by their URL's hash, shared by all messages, bounded in size and evicted least recently used first. Get downloads an image once (through imagefetch: public hosts, no cookies, no Referer) and serves it from disk after that, offline too.

Index ¶

Constants
Variables
func Key(src string) string
type Cache
- func Open(dir string, max int64, client *http.Client) (*Cache, error)
type Image

Constants ¶

View Source

const (
	MaxBytes   = 256 << 20 // the cache's size
	GlobalJobs = 8         // downloads at once
	HostJobs   = 3         // downloads at once from one host

)

Limits of the fetching proxy.

Variables ¶

View Source

var ErrClosed = errors.New("image cache is closed")

ErrClosed is returned by Get after Close.

Functions ¶

func Key ¶

func Key(src string) string

Key is the cache key of a URL: 32 hex digits of its SHA-256.

Types ¶

type Cache ¶

type Cache struct {
	// contains filtered or unexported fields
}

Cache is a directory of images; it is safe for concurrent use.

func Open ¶

func Open(dir string, max int64, client *http.Client) (*Cache, error)

Open is the cache in dir (made if need be), at most max bytes (MaxBytes when 0), downloading with client.

func (*Cache) Cached ¶

func (c *Cache) Cached(src string) bool

Cached reports whether src's image is on disk.

func (*Cache) Clear ¶

func (c *Cache) Clear() error

Clear deletes every cached image.

func (*Cache) Close ¶

func (c *Cache) Close()

Close cancels the downloads in flight and waits for them; Get fails after.

func (*Cache) Dims ¶

func (c *Cache) Dims(src string) (width, height int, ok bool)

Dims is the size of src's image if it is cached; it reads no file.

func (*Cache) Get ¶

func (c *Cache) Get(ctx context.Context, src string) (Image, error)

Get is src's image: from disk, or downloaded now (once, however many ask at the same time). A download goes on when its caller gives up, so the next ask finds it; a URL that failed fails at once for a few minutes.

func (*Cache) Size ¶

func (c *Cache) Size() int64

Size is the bytes the cache takes on disk.

type Image ¶

type Image struct {
	Data          []byte
	Format        string // as imagefetch.Dims names it: png, jpeg, gif or webp
	Width, Height int
}

Image is a cached image.

Source Files ¶

View all Source files

imagecache.go

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