github.com/greenpau/go-authcrunch@v1.1.4/pkg/util/charset/utils.go (about)

     1  // Copyright 2022 Paul Greenberg greenpau@outlook.com
     2  //
     3  // Licensed under the Apache License, Version 2.0 (the "License");
     4  // you may not use this file except in compliance with the License.
     5  // You may obtain a copy of the License at
     6  //
     7  //     http://www.apache.org/licenses/LICENSE-2.0
     8  //
     9  // Unless required by applicable law or agreed to in writing, software
    10  // distributed under the License is distributed on an "AS IS" BASIS,
    11  // WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
    12  // See the License for the specific language governing permissions and
    13  // limitations under the License.
    14  
    15  package utils
    16  
    17  import (
    18  	"fmt"
    19  	"strings"
    20  )
    21  
    22  // TokenChars characters allowed in base64 encoded string.
    23  const TokenChars = "0123456789abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ+/-_="
    24  
    25  // ContainsTokenCharset checks if a string contains non-base64 encoding
    26  // characters.
    27  func ContainsTokenCharset(s string) bool {
    28  	dots := 0
    29  	for _, c := range s {
    30  		if !strings.ContainsRune(TokenChars, c) {
    31  			return false
    32  		}
    33  		// Match dot
    34  		if c == 46 {
    35  			dots++
    36  		}
    37  	}
    38  	if dots != 2 {
    39  		return false
    40  	}
    41  	return true
    42  }
    43  
    44  // ContainsInvalidChars returns error if the provided string contains
    45  // characters outside of the allowed character set.
    46  func ContainsInvalidChars(charset, s string) error {
    47  	for i, c := range s {
    48  		if !strings.Contains(charset, strings.ToLower(string(c))) &&
    49  			!strings.Contains(charset, strings.ToUpper(string(c))) {
    50  			return fmt.Errorf("string %s contains forbidden character %d, pos: %d", s, c, i)
    51  		}
    52  	}
    53  	return nil
    54  }
    55  
    56  // ContainsValidCharset returns error if the provided string contains
    57  // characters outside of the provided character set.
    58  func ContainsValidCharset(charset, s string) error {
    59  	for i, c := range s {
    60  		if !strings.Contains(charset, string(c)) {
    61  			return fmt.Errorf("string %s contains forbidden character %d, pos: %d", s, c, i)
    62  		}
    63  	}
    64  	return nil
    65  }