github.com/Psiphon-Labs/psiphon-tunnel-core@v2.0.28+incompatible/psiphon/transferstats/regexp.go (about)

     1  /*
     2   * Copyright (c) 2015, Psiphon Inc.
     3   * All rights reserved.
     4   *
     5   * This program is free software: you can redistribute it and/or modify
     6   * it under the terms of the GNU General Public License as published by
     7   * the Free Software Foundation, either version 3 of the License, or
     8   * (at your option) any later version.
     9   *
    10   * This program is distributed in the hope that it will be useful,
    11   * but WITHOUT ANY WARRANTY; without even the implied warranty of
    12   * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
    13   * GNU General Public License for more details.
    14   *
    15   * You should have received a copy of the GNU General Public License
    16   * along with this program.  If not, see <http://www.gnu.org/licenses/>.
    17   *
    18   */
    19  
    20  package transferstats
    21  
    22  import (
    23  	"fmt"
    24  	"regexp"
    25  )
    26  
    27  type regexpReplace struct {
    28  	regexp  *regexp.Regexp
    29  	replace string
    30  }
    31  
    32  // Regexps holds the regular expressions and replacement strings used for
    33  // transforming URLs and hostnames into a stats-appropriate forms.
    34  type Regexps []regexpReplace
    35  
    36  // MakeRegexps takes the raw string-map form of the regex-replace pairs
    37  // returned by the server handshake and turns them into a usable object.
    38  func MakeRegexps(hostnameRegexes []map[string]string) (regexps *Regexps, notices []string) {
    39  	regexpsSlice := make(Regexps, 0)
    40  	notices = make([]string, 0)
    41  
    42  	for _, rr := range hostnameRegexes {
    43  		regexString := rr["regex"]
    44  		if regexString == "" {
    45  			notices = append(notices, "MakeRegexps: empty regex")
    46  			continue
    47  		}
    48  
    49  		replace := rr["replace"]
    50  		if replace == "" {
    51  			notices = append(notices, "MakeRegexps: empty replace")
    52  			continue
    53  		}
    54  
    55  		regex, err := regexp.Compile(regexString)
    56  		if err != nil {
    57  			notices = append(notices, fmt.Sprintf("MakeRegexps: failed to compile regex: %s: %s", regexString, err))
    58  			continue
    59  		}
    60  
    61  		regexpsSlice = append(regexpsSlice, regexpReplace{regex, replace})
    62  	}
    63  
    64  	regexps = &regexpsSlice
    65  
    66  	return
    67  }
    68  
    69  // regexHostname processes hostname through the given regexps and returns the
    70  // string that should be used for stats.
    71  func regexHostname(hostname string, regexps *Regexps) (statsHostname string) {
    72  	statsHostname = "(OTHER)"
    73  	if regexps != nil {
    74  		for _, rr := range *regexps {
    75  			if rr.regexp.MatchString(hostname) {
    76  				statsHostname = rr.regexp.ReplaceAllString(hostname, rr.replace)
    77  				break
    78  			}
    79  		}
    80  	}
    81  	return
    82  }