Fossil

** also covers /tarball and /sqlar.  If a tag has an "X" character appended,
** then it only applies if query parameters are such that the page is
** particularly difficult to compute. In all other case, the tag should
** exactly match the page name.
**
** Change this setting "off" to disable all robot restrictions.
*/
/*
** SETTING: robot-exception              width=40 block-text
**
** The value of this setting should be a regular expression.
** If it matches the REQUEST_URI without the SCRIPT_NAME prefix
** matches this regular expression, then the request is an exception
** to anti-robot defenses and should be allowed through.  For
** example, to allow robots to download tarballs or ZIP archives
** for named versions and releases, you could use an expression like
** this:
**
**     ^/(tarball|zip)\\b*\\b(version-|release)\\b
**
** This setting can hold multiple regular expressions, one
** regular expression per line.  The input URL is exempted from
** anti-robot defenses if any of the multiple regular expressions
** matches.
*/

/*
** Return the default restriction GLOB
*/
const char *robot_restrict_default(void){
  return "timelineX,diff,annotate,zip,fileage,file,finfo";
}

    if( zGlob==0 ) zGlob = "";
  }
  if( zGlob[0]==0 || fossil_strcmp(zGlob, "off")==0 ){
    return 0;
  }
  return glob_multi_match(zGlob,zTag);
}

/*
** Check the request URI to see if it matches one of the URI
** exceptions listed in the robot-exception setting.  Return true
** if it does.  Return false if it does not.
**
** For the purposes of this routine, the "request URI" means
** the REQUEST_URI value with the SCRIPT_NAME prefix removed and
** with QUERY_STRING appended with a "?" separator if QUERY_STRING
** is not empty.
**
** If the robot-exception setting does not exist or is an empty
** string, then return false.
*/
int robot_exception(void){
  const char *zRE = db_get("robot-exception",0);
  const char *zQS;    /* QUERY_STRING */
  const char *zURI;   /* REQUEST_URI */
  const char *zSN;    /* SCRIPT_NAME */
  const char *zNL;    /* Next newline character */
  char *zRequest;     /* REQUEST_URL w/o SCRIPT_NAME prefix + QUERY_STRING */
  int nRequest;       /* Length of zRequest in bytes */
  size_t nURI, nSN;   /* Length of zURI and zSN */
  int bMatch = 0;     /* True if there is a match */

  if( zRE==0 ) return 0;
  if( zRE[0]==0 ) return 0;
  zURI = PD("REQUEST_URI","");
  nURI = strlen(zURI);
  zSN = PD("SCRIPT_NAME","");
  nSN = strlen(zSN);
  if( nSN<=nURI ) zURI += nSN;
  zQS = P("QUERY_STRING");
  if( zQS && zQS[0] ){
    zRequest = mprintf("%s?%s", zURI, zQS);
  }else{
    zRequest = fossil_strdup(zURI);
  }
  nRequest = (int)strlen(zRequest);
  while( zRE[0] && bMatch==0 ){
    char *z;
    const char *zErr;
    size_t n;
    ReCompiled *pRe;
    zNL = strchr(zRE,'\n');
    if( zNL ){
      n = (size_t)(zNL - zRE)+1;
      while( zNL>zRE && fossil_isspace(zNL[0]) ) zNL--;
      if( zNL==zRE ){
        zRE += n;
        continue;
      }
    }else{
      n = strlen(zRE);
    }
    z = mprintf("%.*s", (int)(zNL - zRE)+1, zRE);
    zRE += n;
    zErr = re_compile(&pRe, z, 0);
    if( zErr ){
      fossil_warning("robot-exception error \"%s\" in expression \"%s\"\n",
                     zErr, z);
      fossil_free(z);
      continue;
    }
    fossil_free(z);
    bMatch = re_match(pRe, (const unsigned char*)zRequest, nRequest);
    re_free(pRe);
  }
  fossil_free(zRequest);
  return bMatch;
}

/*
** Check to see if the page named in the argument is on the
** robot-restrict list.  If it is on the list and if the user
** is "nobody" then bring up a captcha to test to make sure that
** client is not a robot.
**
** This routine returns true if a captcha was rendered and if subsequent
** page generation should be aborted.  It returns false if the page
** should not be restricted and should be rendered normally.
*/
int robot_restrict(const char *zTag){
  if( robot.resultCache==KNOWN_NOT_ROBOT ) return 0;
  if( !robot_restrict_has_tag(zTag) ) return 0;
  if( !client_might_be_a_robot() ) return 0;
  if( robot_exception() ){
    robot.resultCache = KNOWN_NOT_ROBOT;
    return 0;
  }

  /* Generate the proof-of-work captcha */   
  ask_for_proof_that_client_is_not_robot();
  return 1;
}

/*