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utils.go
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utils.go
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// Copyright (c) 2015-present Mattermost, Inc. All Rights Reserved.
// See LICENSE.txt for license information.
package utils
import (
"github.com/pkg/errors"
"io/ioutil"
"net"
"net/http"
"net/url"
"strings"
)
func StringInSlice(a string, slice []string) bool {
for _, b := range slice {
if b == a {
return true
}
}
return false
}
// RemoveStringFromSlice removes the first occurrence of a from slice.
func RemoveStringFromSlice(a string, slice []string) []string {
for i, str := range slice {
if str == a {
return append(slice[:i], slice[i+1:]...)
}
}
return slice
}
// RemoveStringsFromSlice removes all occurrences of strings from slice.
func RemoveStringsFromSlice(slice []string, strings ...string) []string {
newSlice := []string{}
for _, item := range slice {
if !StringInSlice(item, strings) {
newSlice = append(newSlice, item)
}
}
return newSlice
}
func StringArrayIntersection(arr1, arr2 []string) []string {
arrMap := map[string]bool{}
result := []string{}
for _, value := range arr1 {
arrMap[value] = true
}
for _, value := range arr2 {
if arrMap[value] {
result = append(result, value)
}
}
return result
}
func RemoveDuplicatesFromStringArray(arr []string) []string {
result := make([]string, 0, len(arr))
seen := make(map[string]bool)
for _, item := range arr {
if !seen[item] {
result = append(result, item)
seen[item] = true
}
}
return result
}
func StringSliceDiff(a, b []string) []string {
m := make(map[string]bool)
result := []string{}
for _, item := range b {
m[item] = true
}
for _, item := range a {
if !m[item] {
result = append(result, item)
}
}
return result
}
func GetIpAddress(r *http.Request, trustedProxyIPHeader []string) string {
address := ""
for _, proxyHeader := range trustedProxyIPHeader {
header := r.Header.Get(proxyHeader)
if len(header) > 0 {
addresses := strings.Fields(header)
if len(addresses) > 0 {
address = strings.TrimRight(addresses[0], ",")
}
}
if len(address) > 0 {
return address
}
}
if len(address) == 0 {
address, _, _ = net.SplitHostPort(r.RemoteAddr)
}
return address
}
func GetHostnameFromSiteURL(siteURL string) string {
u, err := url.Parse(siteURL)
if err != nil {
return ""
}
return u.Hostname()
}
type RequestCache struct {
Data []byte
Date string
Key string
}
// Fetch JSON data from the notices server
// if skip is passed, does a fetch without touching the cache
func GetUrlWithCache(url string, cache *RequestCache, skip bool) ([]byte, error) {
// Build a GET Request, including optional If-None-Match header.
req, err := http.NewRequest("GET", url, nil)
if err != nil {
cache.Data = nil
return nil, err
}
if !skip && cache.Data != nil {
req.Header.Add("If-None-Match", cache.Key)
req.Header.Add("If-Modified-Since", cache.Date)
}
client := &http.Client{}
resp, err := client.Do(req)
if err != nil {
cache.Data = nil
return nil, err
}
defer resp.Body.Close()
// No change from latest known Etag?
if resp.StatusCode == http.StatusNotModified {
return cache.Data, nil
}
if resp.StatusCode != 200 {
cache.Data = nil
return nil, errors.Errorf("Fetching notices failed with status code %d", resp.StatusCode)
}
cache.Data, err = ioutil.ReadAll(resp.Body)
if err != nil {
cache.Data = nil
return nil, err
}
// If etags headers are missing, ignore.
cache.Key = resp.Header.Get("ETag")
cache.Date = resp.Header.Get("Date")
return cache.Data, err
}