screenshot

Documentation

Index

• Constants
• Variables
• func RecentScreenshotHashes(ds shared.Datastore, browser, browserVersion, os, osVersion string, limit *int) ([]string, error)
• func RegisterRoutes()
• type Screenshot
  • func NewScreenshot(labels ...string) *Screenshot
  • func (s *Screenshot) Hash() string
  • func (s *Screenshot) Key() string
  • func (s *Screenshot) SetHashFromFile(f io.Reader, hashMethod string) error
  • func (s *Screenshot) Store(ds shared.Datastore) error

Constants

const MaxItemsInResponse = 10000

MaxItemsInResponse is the maximum number of hashes that will be returned when asked for recent screenshots.

Variables

var (
	// ErrInvalidHash is the error when a hash string is invalid.
	ErrInvalidHash = errors.New("invalid hash string")
	// ErrUnsupportedHashMethod is the error when the requested hash method
	// is not supported.
	ErrUnsupportedHashMethod = errors.New("hash method unsupported")
)

Functions

func RecentScreenshotHashes

func RecentScreenshotHashes(
	ds shared.Datastore,
	browser,
	browserVersion,
	os,
	osVersion string,
	limit *int,
) ([]string, error)

RecentScreenshotHashes gets the most recently used screenshot hash strings based on the given arguments.

We first try to find screenshots with all the four labels. When there are not enough, we remove the least important label and try again.

func RegisterRoutes

func RegisterRoutes()

RegisterRoutes adds all the screenshot route handlers.

Types

type Screenshot

type Screenshot struct {
	HashDigest string
	HashMethod string
	Labels     []string
	// These two fields can be left empty and will be filled by Store().
	Counter  int
	LastUsed time.Time
}

Screenshot is the entity stored in Datastore for a known screenshot hash and its metadata.

func NewScreenshot

func NewScreenshot(labels ...string) *Screenshot

NewScreenshot creates a new Screenshot with the given labels (empty labels are omitted).

func (*Screenshot) Hash

func (s *Screenshot) Hash() string

Hash returns the "HASH_METHOD:HASH_DIGEST" representation of the screenshot used in the API.

func (*Screenshot) Key

func (s *Screenshot) Key() string

Key returns the Datastore name key for this screenshot.

Note that the order of HashDigest and HashMethod is inversed for better key space distribution.

func (*Screenshot) SetHashFromFile

func (s *Screenshot) SetHashFromFile(f io.Reader, hashMethod string) error

SetHashFromFile hashes a file and sets the HashMethod and HashDigest fields.

func (*Screenshot) Store

func (s *Screenshot) Store(ds shared.Datastore) error

Store finalizes the struct and stores it to Datastore.

Before writing to Datastore, this function will first check if there is an existing record with the same key; if so, it updates the struct to include all existing Labels and sets Counter to existing Counter + 1. Note that this is NOT done in a transaction for better performance (both Labels and Counter are auxiliary information that is OK to lose in a race condition). Lastly, LastUsed is populated with the current timestamp.