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// package util implements several utility functions that are used across the codebase
package util
import (
"crypto/rand"
"fmt"
"net/url"
"os"
"path"
"strings"
"github.com/eduvpn/eduvpn-common/types"
)
// EnsureValidURL ensures that the input URL is valid to be used internally
// It does the following
// - Sets the scheme to https if none is given
// - It 'cleans' up the path using path.Clean
// - It makes sure that the URL ends with a /
// It returns an error if the URL cannot be parsed.
func EnsureValidURL(s string) (string, error) {
parsedURL, parseErr := url.Parse(s)
if parseErr != nil {
return "", types.NewWrappedError(
fmt.Sprintf("failed parsing url: %s", s),
parseErr,
)
}
if parsedURL.Scheme == "" {
parsedURL.Scheme = "https"
}
if parsedURL.Path != "" {
// Clean the path
// https://pkg.go.dev/path#Clean
parsedURL.Path = path.Clean(parsedURL.Path)
}
returnedURL := parsedURL.String()
// Make sure the URL ends with a /
if returnedURL[len(returnedURL)-1:] != "/" {
returnedURL = returnedURL + "/"
}
return returnedURL, nil
}
// MakeRandomByteSlice creates a cryptographically random byteslice of `size`
// It returns the byte slice (or nil if error) and an error if it could not be generated.
func MakeRandomByteSlice(size int) ([]byte, error) {
byteSlice := make([]byte, size)
_, err := rand.Read(byteSlice)
if err != nil {
return nil, types.NewWrappedError("failed reading random", err)
}
return byteSlice, nil
}
// EnsureDirectory creates a directory with permission 700.
func EnsureDirectory(directory string) error {
// Create with 700 permissions, read, write, execute only for the owner
mkdirErr := os.MkdirAll(directory, 0o700)
if mkdirErr != nil {
return types.NewWrappedError(
fmt.Sprintf("failed to create directory %s", directory),
mkdirErr,
)
}
return nil
}
// WAYFEncode an input URL using 'skip Where Are You From' encoding
// See https://github.com/eduvpn/documentation/blob/dc4d53c47dd7a69e95d6650eec408e16eaa814a2/SERVER_DISCOVERY_SKIP_WAYF.md
// URL encode for skipping where are you from (WAYF). Note that this right now is basically an alias to QueryEscape.
func WAYFEncode(input string) string {
// QueryReplace already replaces a space with a +
// see https://go.dev/play/p/pOfrn-Wsq5
return url.QueryEscape(input)
}
// ReplaceWAYF replaces an authorization template containing of @RETURN_TO@ and @ORG_ID@ with the authorization URL and the organization ID
// See https://github.com/eduvpn/documentation/blob/dc4d53c47dd7a69e95d6650eec408e16eaa814a2/SERVER_DISCOVERY_SKIP_WAYF.md
func ReplaceWAYF(authTemplate string, authURL string, orgID string) string {
// We just return the authURL in the cases where the template is not given or is invalid
if authTemplate == "" {
return authURL
}
if !strings.Contains(authTemplate, "@RETURN_TO@") {
return authURL
}
if !strings.Contains(authTemplate, "@ORG_ID@") {
return authURL
}
// Replace authURL
authTemplate = strings.Replace(authTemplate, "@RETURN_TO@", url.QueryEscape(authURL), 1)
// If now there is no more ORG_ID, return as there weren't enough @ symbols
if !strings.Contains(authTemplate, "@ORG_ID@") {
return authURL
}
// Replace ORG ID
authTemplate = strings.Replace(authTemplate, "@ORG_ID@", url.QueryEscape(orgID), 1)
return authTemplate
}
// GetLanguageMatched uses a map from language tags to strings to extract the right language given the tag
// It implements it according to https://github.com/eduvpn/documentation/blob/dc4d53c47dd7a69e95d6650eec408e16eaa814a2/SERVER_DISCOVERY.md#language-matching
func GetLanguageMatched(languageMap map[string]string, languageTag string) string {
// If no map is given, return the empty string
if len(languageMap) == 0 {
return ""
}
// Try to find the exact match
if val, ok := languageMap[languageTag]; ok {
return val
}
// Try to find a key that starts with the OS language setting
for k := range languageMap {
if strings.HasPrefix(k, languageTag) {
return languageMap[k]
}
}
// Try to find a key that starts with the first part of the OS language (e.g. de-)
splitted := strings.Split(languageTag, "-")
// We have a "-"
if len(splitted) > 1 {
for k := range languageMap {
if strings.HasPrefix(k, splitted[0]+"-") {
return languageMap[k]
}
}
}
// search for just the language (e.g. de)
for k := range languageMap {
if k == splitted[0] {
return languageMap[k]
}
}
// Pick one that is deemed best, e.g. en-US or en, but note that not all languages are always available!
// We force an entry that is english exactly or with an english prefix
for k := range languageMap {
if k == "en" || strings.HasPrefix(k, "en-") {
return languageMap[k]
}
}
// Otherwise just return one
for k := range languageMap {
return languageMap[k]
}
return ""
}
|
