proxy

Documentation

Overview

Package data provides common shared data structures for imageproxy.

Package proxy provides the image proxy.

Package transform handles image transformation such as resizing.

Index

• Variables
• func Transform(img []byte, opt *Options) ([]byte, error)
• type Cache
• type Options
  • func ParseOptions(str string) *Options
  • func (o Options) String() string
• type Proxy
  • func NewProxy(transport http.RoundTripper, cache Cache) *Proxy
  • func (p *Proxy) ServeHTTP(w http.ResponseWriter, r *http.Request)
• type Request
  • func NewRequest(r *http.Request) (*Request, error)
• type TransformingTransport
  • func (t *TransformingTransport) RoundTrip(req *http.Request) (*http.Response, error)
• type URLError
  • func (e URLError) Error() string

Variables

var NopCache = new(nopCache)

NopCache provides a no-op cache implementation that doesn't actually cache anything.

Functions

func Transform

func Transform(img []byte, opt *Options) ([]byte, error)

Transform the provided image.

Types

type Cache

type Cache interface {
	// Get retrieves the cached data for the provided key.
	Get(key string) (data []byte, ok bool)

	// Set caches the provided data.
	Set(key string, data []byte)

	// Delete deletes the cached data at the specified key.
	Delete(key string)
}

The Cache interface defines a cache for storing arbitrary data. The interface is designed to align with httpcache.Cache.

type Options

type Options struct {
	Width  float64 // requested width, in pixels
	Height float64 // requested height, in pixels

	// If true, resize the image to fit in the specified dimensions.  Image
	// will not be cropped, and aspect ratio will be maintained.
	Fit bool

	// Rotate image the specified degrees counter-clockwise.  Valid values are 90, 180, 270.
	Rotate int

	FlipVertical   bool
	FlipHorizontal bool
}

Options specifies transformations that can be performed on a requested image.

func ParseOptions

func ParseOptions(str string) *Options

func (Options) String

func (o Options) String() string

type Proxy

type Proxy struct {
	Client *http.Client // client used to fetch remote URLs
	Cache  Cache

	// Whitelist specifies a list of remote hosts that images can be proxied from.  An empty list means all hosts are allowed.
	Whitelist []string

	MaxWidth  int
	MaxHeight int
}

Proxy serves image requests.

func NewProxy

func NewProxy(transport http.RoundTripper, cache Cache) *Proxy

NewProxy constructs a new proxy. The provided http Client will be used to fetch remote URLs. If nil is provided, http.DefaultClient will be used.

func (*Proxy) ServeHTTP

func (p *Proxy) ServeHTTP(w http.ResponseWriter, r *http.Request)

ServeHTTP handles image requests.

type Request

type Request struct {
	URL     *url.URL // URL of the image to proxy
	Options *Options // Image transformation to perform
}

func NewRequest

func NewRequest(r *http.Request) (*Request, error)

NewRequest parses an http.Request into an image request.

type TransformingTransport

type TransformingTransport struct {
	// Transport is used to satisfy non-transform requests (those that do not include a URL fragment)
	Transport http.RoundTripper

	// Client is used to fetch images to be resized.
	Client *http.Client
}

TransformingTransport is an implementation of http.RoundTripper that optionally transforms images using the options specified in the request URL fragment.

func (*TransformingTransport) RoundTrip

func (t *TransformingTransport) RoundTrip(req *http.Request) (*http.Response, error)

RoundTrip implements http.RoundTripper.

type URLError

type URLError struct {
	Message string
	URL     *url.URL
}

URLError reports a malformed URL error.

func (URLError) Error

func (e URLError) Error() string