util

Documentation

Index

• Variables
• func BasicAuth(user, pass string) string
• func DetectContentType(b []byte, filename string) (mimeType string, ext string)
• func DurationToHuman(d time.Duration) (str string)
• func ExpandHome(path string) string
• func FileExists(filename string) bool
• func InIntList(haystack []int, needle int) bool
• func InStringList(haystack []string, needle string) bool
• func InStringListAll(haystack []string, needles []string) bool
• func ParseFutureTime(s string, now time.Time) (time.Time, error)
• func ParsePriority(priority string) (int, error)
• func ParseSize(s string) (int64, error)
• func PriorityString(priority int) (string, error)
• func RandomString(length int) string
• func ReadPassword(in io.Reader) ([]byte, error)
• func ShortTopicURL(s string) string
• func SplitNoEmpty(s string, sep string) []string
• func ValidRandomString(s string, length int) bool
• type CachingEmbedFS
  • func (f CachingEmbedFS) Open(name string) (fs.File, error)
• type ContentTypeWriter
  • func NewContentTypeWriter(w http.ResponseWriter, filename string) *ContentTypeWriter
  • func (w *ContentTypeWriter) Write(p []byte) (n int, err error)
• type FixedLimiter
  • func NewFixedLimiter(limit int64) *FixedLimiter
  • func (l *FixedLimiter) Allow(n int64) error
• type LimitWriter
  • func NewLimitWriter(w io.Writer, limiters ...Limiter) *LimitWriter
  • func (w *LimitWriter) Write(p []byte) (n int, err error)
• type Limiter
• type PeakedReadCloser
  • func Peak(underlying io.ReadCloser, limit int) (*PeakedReadCloser, error)
  • func (r *PeakedReadCloser) Close() error
  • func (r *PeakedReadCloser) Read(p []byte) (n int, err error)
• type RateLimiter
  • func NewBytesLimiter(bytes int, interval time.Duration) *RateLimiter
  • func NewRateLimiter(r rate.Limit, b int) *RateLimiter
  • func (l *RateLimiter) Allow(n int64) error

Variables

var ErrLimitReached = errors.New("limit reached")

ErrLimitReached is the error returned by the Limiter and LimitWriter when the predefined limit has been reached

Functions

func BasicAuth

func BasicAuth(user, pass string) string

BasicAuth encodes the Authorization header value for basic auth

func DetectContentType

func DetectContentType(b []byte, filename string) (mimeType string, ext string)

DetectContentType probes the byte array b and returns mime type and file extension. The filename is only used to override certain special cases.

func DurationToHuman

func DurationToHuman(d time.Duration) (str string)

DurationToHuman converts a duration to a human-readable format

func ExpandHome

func ExpandHome(path string) string

ExpandHome replaces "~" with the user's home directory

func FileExists

func FileExists(filename string) bool

FileExists checks if a file exists, and returns true if it does

func InIntList

func InIntList(haystack []int, needle int) bool

InIntList returns true if needle is contained in haystack

func InStringList

func InStringList(haystack []string, needle string) bool

InStringList returns true if needle is contained in haystack

func InStringListAll

func InStringListAll(haystack []string, needles []string) bool

InStringListAll returns true if all needles are contained in haystack

func ParseFutureTime

func ParseFutureTime(s string, now time.Time) (time.Time, error)

ParseFutureTime parses a date/time string to a time.Time. It supports unix timestamps, durations and natural language dates

func ParsePriority

func ParsePriority(priority string) (int, error)

ParsePriority parses a priority string into its equivalent integer value

func ParseSize

func ParseSize(s string) (int64, error)

ParseSize parses a size string like 2K or 2M into bytes. If no unit is found, e.g. 123, bytes is assumed.

func PriorityString

func PriorityString(priority int) (string, error)

PriorityString converts a priority number to a string

func RandomString

func RandomString(length int) string

RandomString returns a random string with a given length

func ReadPassword

func ReadPassword(in io.Reader) ([]byte, error)

ReadPassword will read a password from STDIN. If the terminal supports it, it will not print the input characters to the screen. If not, it'll just read using normal readline semantics (useful for testing).

func ShortTopicURL

func ShortTopicURL(s string) string

ShortTopicURL shortens the topic URL to be human-friendly, removing the http:// or https://

func SplitNoEmpty

func SplitNoEmpty(s string, sep string) []string

SplitNoEmpty splits a string using strings.Split, but filters out empty strings

func ValidRandomString

func ValidRandomString(s string, length int) bool

ValidRandomString returns true if the given string matches the format created by RandomString

Types

type CachingEmbedFS

type CachingEmbedFS struct {
	ModTime time.Time
	FS      embed.FS
}

CachingEmbedFS is a wrapper around embed.FS that allows setting a ModTime, so that the default static file server can send 304s back. It can be used like this:

  var (
     //go:embed docs
     docsStaticFs     embed.FS
     docsStaticCached = &util.CachingEmbedFS{ModTime: time.Now(), FS: docsStaticFs}
  )

	 http.FileServer(http.FS(docsStaticCached)).ServeHTTP(w, r)

func (CachingEmbedFS) Open

func (f CachingEmbedFS) Open(name string) (fs.File, error)

Open opens a file in the embedded filesystem and returns a fs.File with the static ModTime

type ContentTypeWriter

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

ContentTypeWriter is an implementation of http.ResponseWriter that will detect the content type and set the Content-Type and (optionally) Content-Disposition headers accordingly.

It will always set a Content-Type based on http.DetectContentType, but will never send the "text/html" content type.

func NewContentTypeWriter

func NewContentTypeWriter(w http.ResponseWriter, filename string) *ContentTypeWriter

NewContentTypeWriter creates a new ContentTypeWriter

func (*ContentTypeWriter) Write

func (w *ContentTypeWriter) Write(p []byte) (n int, err error)

type FixedLimiter

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

FixedLimiter is a helper that allows adding values up to a well-defined limit. Once the limit is reached ErrLimitReached will be returned. FixedLimiter may be used by multiple goroutines.

func NewFixedLimiter

func NewFixedLimiter(limit int64) *FixedLimiter

NewFixedLimiter creates a new Limiter

func (*FixedLimiter) Allow

func (l *FixedLimiter) Allow(n int64) error

Allow adds n to the limiters internal value, but only if the limit has not been reached. If the limit was exceeded after adding n, ErrLimitReached is returned.

type LimitWriter

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

LimitWriter implements an io.Writer that will pass through all Write calls to the underlying writer w until any of the limiter's limit is reached, at which point a Write will return ErrLimitReached. Each limiter's value is increased with every write.

func NewLimitWriter

func NewLimitWriter(w io.Writer, limiters ...Limiter) *LimitWriter

NewLimitWriter creates a new LimitWriter

func (*LimitWriter) Write

func (w *LimitWriter) Write(p []byte) (n int, err error)

Write passes through all writes to the underlying writer until any of the given limiter's limit is reached

type Limiter

type Limiter interface {
	// Allow adds n to the limiters internal value, or returns ErrLimitReached if the limit has been reached
	Allow(n int64) error
}

Limiter is an interface that implements a rate limiting mechanism, e.g. based on time or a fixed value

type PeakedReadCloser

type PeakedReadCloser struct {
	PeakedBytes  []byte
	LimitReached bool
	// contains filtered or unexported fields
}

PeakedReadCloser is a ReadCloser that allows peaking into a stream and buffering it in memory. It can be instantiated using the Peak function. After a stream has been peaked, it can still be fully read by reading the PeakedReadCloser. It first drained from the memory buffer, and then from the remaining underlying reader.

func Peak

func Peak(underlying io.ReadCloser, limit int) (*PeakedReadCloser, error)

Peak reads the underlying ReadCloser into memory up until the limit and returns a PeakedReadCloser

func (*PeakedReadCloser) Close

func (r *PeakedReadCloser) Close() error

Close closes the underlying stream

func (*PeakedReadCloser) Read

func (r *PeakedReadCloser) Read(p []byte) (n int, err error)

Read reads from the peaked bytes and then from the underlying stream

type RateLimiter

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

RateLimiter is a Limiter that wraps a rate.Limiter, allowing a floating time-based limit.

func NewBytesLimiter

func NewBytesLimiter(bytes int, interval time.Duration) *RateLimiter

NewBytesLimiter creates a RateLimiter that is meant to be used for a bytes-per-interval limit, e.g. 250 MB per day. And example of the underlying idea can be found here: https://go.dev/play/p/0ljgzIZQ6dJ

func NewRateLimiter

func NewRateLimiter(r rate.Limit, b int) *RateLimiter

NewRateLimiter creates a new RateLimiter

func (*RateLimiter) Allow

func (l *RateLimiter) Allow(n int64) error

Allow adds n to the limiters internal value, but only if the limit has not been reached. If the limit was exceeded after adding n, ErrLimitReached is returned.