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ntfy/util/util.go
2023-02-09 15:24:12 -05:00

390 lines
10 KiB
Go

package util
import (
"bytes"
"encoding/base64"
"encoding/json"
"errors"
"fmt"
"golang.org/x/time/rate"
"io"
"math/rand"
"net/netip"
"os"
"regexp"
"strconv"
"strings"
"sync"
"time"
"github.com/gabriel-vasile/mimetype"
"golang.org/x/term"
)
const (
randomStringCharset = "abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789"
)
var (
random = rand.New(rand.NewSource(time.Now().UnixNano()))
randomMutex = sync.Mutex{}
sizeStrRegex = regexp.MustCompile(`(?i)^(\d+)([gmkb])?$`)
errInvalidPriority = errors.New("invalid priority")
noQuotesRegex = regexp.MustCompile(`^[-_./:@a-zA-Z0-9]+$`)
)
// Errors for UnmarshalJSON and UnmarshalJSONWithLimit functions
var (
ErrUnmarshalJSON = errors.New("unmarshalling JSON failed")
ErrTooLargeJSON = errors.New("too large JSON")
)
// FileExists checks if a file exists, and returns true if it does
func FileExists(filename string) bool {
stat, _ := os.Stat(filename)
return stat != nil
}
// Contains returns true if needle is contained in haystack
func Contains[T comparable](haystack []T, needle T) bool {
for _, s := range haystack {
if s == needle {
return true
}
}
return false
}
// ContainsIP returns true if any one of the of prefixes contains the ip.
func ContainsIP(haystack []netip.Prefix, needle netip.Addr) bool {
for _, s := range haystack {
if s.Contains(needle) {
return true
}
}
return false
}
// ContainsAll returns true if all needles are contained in haystack
func ContainsAll[T comparable](haystack []T, needles []T) bool {
matches := 0
for _, s := range haystack {
for _, needle := range needles {
if s == needle {
matches++
}
}
}
return matches == len(needles)
}
// SplitNoEmpty splits a string using strings.Split, but filters out empty strings
func SplitNoEmpty(s string, sep string) []string {
res := make([]string, 0)
for _, r := range strings.Split(s, sep) {
if r != "" {
res = append(res, r)
}
}
return res
}
// SplitKV splits a string into a key/value pair using a separator, and trimming space. If the separator
// is not found, key is empty.
func SplitKV(s string, sep string) (key string, value string) {
kv := strings.SplitN(strings.TrimSpace(s), sep, 2)
if len(kv) == 2 {
return strings.TrimSpace(kv[0]), strings.TrimSpace(kv[1])
}
return "", strings.TrimSpace(kv[0])
}
// LastString returns the last string in a slice, or def if s is empty
func LastString(s []string, def string) string {
if len(s) == 0 {
return def
}
return s[len(s)-1]
}
// RandomString returns a random string with a given length
func RandomString(length int) string {
return RandomStringPrefix("", length)
}
// RandomStringPrefix returns a random string with a given length, with a prefix
func RandomStringPrefix(prefix string, length int) string {
randomMutex.Lock() // Who would have thought that random.Intn() is not thread-safe?!
defer randomMutex.Unlock()
b := make([]byte, length-len(prefix))
for i := range b {
b[i] = randomStringCharset[random.Intn(len(randomStringCharset))]
}
return prefix + string(b)
}
// ValidRandomString returns true if the given string matches the format created by RandomString
func ValidRandomString(s string, length int) bool {
if len(s) != length {
return false
}
for _, c := range strings.Split(s, "") {
if !strings.Contains(randomStringCharset, c) {
return false
}
}
return true
}
// ParsePriority parses a priority string into its equivalent integer value
func ParsePriority(priority string) (int, error) {
p := strings.TrimSpace(strings.ToLower(priority))
switch p {
case "":
return 0, nil
case "1", "min":
return 1, nil
case "2", "low":
return 2, nil
case "3", "default":
return 3, nil
case "4", "high":
return 4, nil
case "5", "max", "urgent":
return 5, nil
default:
// Ignore new HTTP Priority header (see https://datatracker.ietf.org/doc/html/draft-ietf-httpbis-priority)
// Cloudflare adds this to requests when forwarding to the backend (ntfy), so we just ignore it.
if strings.HasPrefix(p, "u=") {
return 3, nil
}
return 0, errInvalidPriority
}
}
// PriorityString converts a priority number to a string
func PriorityString(priority int) (string, error) {
switch priority {
case 0:
return "default", nil
case 1:
return "min", nil
case 2:
return "low", nil
case 3:
return "default", nil
case 4:
return "high", nil
case 5:
return "max", nil
default:
return "", errInvalidPriority
}
}
// ShortTopicURL shortens the topic URL to be human-friendly, removing the http:// or https://
func ShortTopicURL(s string) string {
return strings.TrimPrefix(strings.TrimPrefix(s, "https://"), "http://")
}
// DetectContentType probes the byte array b and returns mime type and file extension.
// The filename is only used to override certain special cases.
func DetectContentType(b []byte, filename string) (mimeType string, ext string) {
if strings.HasSuffix(strings.ToLower(filename), ".apk") {
return "application/vnd.android.package-archive", ".apk"
}
m := mimetype.Detect(b)
mimeType, ext = m.String(), m.Extension()
if ext == "" {
ext = ".bin"
}
return
}
// ParseSize parses a size string like 2K or 2M into bytes. If no unit is found, e.g. 123, bytes is assumed.
func ParseSize(s string) (int64, error) {
matches := sizeStrRegex.FindStringSubmatch(s)
if matches == nil {
return -1, fmt.Errorf("invalid size %s", s)
}
value, err := strconv.Atoi(matches[1])
if err != nil {
return -1, fmt.Errorf("cannot convert number %s", matches[1])
}
switch strings.ToUpper(matches[2]) {
case "G":
return int64(value) * 1024 * 1024 * 1024, nil
case "M":
return int64(value) * 1024 * 1024, nil
case "K":
return int64(value) * 1024, nil
default:
return int64(value), nil
}
}
// FormatSize formats bytes into a human-readable notation, e.g. 2.1 MB
func FormatSize(b int64) string {
const unit = 1024
if b < unit {
return fmt.Sprintf("%d bytes", b)
}
div, exp := int64(unit), 0
for n := b / unit; n >= unit; n /= unit {
div *= unit
exp++
}
return fmt.Sprintf("%.1f %cB", float64(b)/float64(div), "KMGTPE"[exp])
}
// 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 ReadPassword(in io.Reader) ([]byte, error) {
// If in is a file and a character device (a TTY), use term.ReadPassword
if f, ok := in.(*os.File); ok {
stat, err := f.Stat()
if err != nil {
return nil, err
}
if (stat.Mode() & os.ModeCharDevice) == os.ModeCharDevice {
password, err := term.ReadPassword(int(f.Fd())) // This is always going to be 0
if err != nil {
return nil, err
}
return password, nil
}
}
// Fallback: Manually read util \n if found, see #69 for details why this is so manual
password := make([]byte, 0)
buf := make([]byte, 1)
for {
_, err := in.Read(buf)
if err == io.EOF || buf[0] == '\n' {
break
} else if err != nil {
return nil, err
} else if len(password) > 10240 {
return nil, errors.New("passwords this long are not supported")
}
password = append(password, buf[0])
}
return password, nil
}
// BasicAuth encodes the Authorization header value for basic auth
func BasicAuth(user, pass string) string {
return fmt.Sprintf("Basic %s", base64.StdEncoding.EncodeToString([]byte(fmt.Sprintf("%s:%s", user, pass))))
}
// BearerAuth encodes the Authorization header value for a bearer/token auth
func BearerAuth(token string) string {
return fmt.Sprintf("Bearer %s", token)
}
// MaybeMarshalJSON returns a JSON string of the given object, or "<cannot serialize>" if serialization failed.
// This is useful for logging purposes where a failure doesn't matter that much.
func MaybeMarshalJSON(v any) string {
jsonBytes, err := json.MarshalIndent(v, "", " ")
if err != nil {
return "<cannot serialize>"
}
if len(jsonBytes) > 5000 {
return string(jsonBytes)[:5000]
}
return string(jsonBytes)
}
// QuoteCommand combines a command array to a string, quoting arguments that need quoting.
// This function is naive, and sometimes wrong. It is only meant for lo pretty-printing a command.
//
// Warning: Never use this function with the intent to run the resulting command.
//
// Example:
//
// []string{"ls", "-al", "Document Folder"} -> ls -al "Document Folder"
func QuoteCommand(command []string) string {
var quoted []string
for _, c := range command {
if noQuotesRegex.MatchString(c) {
quoted = append(quoted, c)
} else {
quoted = append(quoted, fmt.Sprintf(`"%s"`, c))
}
}
return strings.Join(quoted, " ")
}
// UnmarshalJSON reads the given io.ReadCloser into a struct
func UnmarshalJSON[T any](body io.ReadCloser) (*T, error) {
var obj T
if err := json.NewDecoder(body).Decode(&obj); err != nil {
return nil, ErrUnmarshalJSON
}
return &obj, nil
}
// UnmarshalJSONWithLimit reads the given io.ReadCloser into a struct, but only until limit is reached
func UnmarshalJSONWithLimit[T any](r io.ReadCloser, limit int, allowEmpty bool) (*T, error) {
defer r.Close()
p, err := Peek(r, limit)
if err != nil {
return nil, err
} else if p.LimitReached {
return nil, ErrTooLargeJSON
}
var obj T
if len(bytes.TrimSpace(p.PeekedBytes)) == 0 && allowEmpty {
return &obj, nil
} else if err := json.NewDecoder(p).Decode(&obj); err != nil {
return nil, ErrUnmarshalJSON
}
return &obj, nil
}
// Retry executes function f until if succeeds, and then returns t. If f fails, it sleeps
// and tries again. The sleep durations are passed as the after params.
func Retry[T any](f func() (*T, error), after ...time.Duration) (t *T, err error) {
for _, delay := range after {
if t, err = f(); err == nil {
return t, nil
}
time.Sleep(delay)
}
return nil, err
}
// MinMax returns value if it is between min and max, or either
// min or max if it is out of range
func MinMax[T int | int64](value, min, max T) T {
if value < min {
return min
} else if value > max {
return max
}
return value
}
// Max returns the maximum value of the two given values
func Max[T int | int64 | rate.Limit](a, b T) T {
if a > b {
return a
}
return b
}
// String turns a string into a pointer of a string
func String(v string) *string {
return &v
}
// Int turns a string into a pointer of an int
func Int(v int) *int {
return &v
}
// Time turns a time.Time into a pointer
func Time(v time.Time) *time.Time {
return &v
}