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// -*-go-*-
//
// URL Parser
// Copyright (c) 2010 J.A. Roberts Tunney
// MIT License
//
package main
import (
"errors"
"fmt"
"strconv"
)
%% machine url_authority;
%% write data;
// i parse strings like `alice@pokémon.com`.
//
// sounds simple right? but i also parse stuff like:
//
// bob%20barker:priceisright@[dead:beef::666]:5060;isup-oli=00
//
// which in actual reality is:
//
// - User: "bob barker"
// - Pass: "priceisright"
// - Host: "dead:beef::666"
// - Port: 5060
// - Params: "isup-oli=00"
//
// which was probably extracted from an absolute url that looked like:
//
// sip:bob%20barker:priceisright@[dead:beef::666]:5060;isup-oli=00/palfun.html?haha#omg
//
// which was probably extracted from its address form:
//
// "Bob Barker" <sip:bob%20barker:priceisright@[dead:beef::666]:5060;isup-oli=00/palfun.html?haha#omg>;tag=666
//
// who would have thought this could be so hard ._.
func (url *URL) parseAuthority(data []byte) (err error) {
cs, p, pe, eof := 0, 0, len(data), len(data)
mark := 0
// temporary holding place for user:pass and/or host:port cuz an
// optional term (user[:pass]) coming before a mandatory term
// (host[:pass]) would require require backtracking and all that
// evil nondeterministic stuff which ragel seems to hate. (for
// this same reason you're also allowed to use square quotes
// around the username.)
var b1, b2 string
// this buffer is so we can unescape while we roll
var hex byte
buf := make([]byte, len(data))
amt := 0
%%{
action mark { mark = p }
action str_start { amt = 0 }
action str_char { buf[amt] = fc; amt++ }
action hex_hi { hex = unhex(fc) * 16 }
action hex_lo { hex += unhex(fc)
buf[amt] = hex; amt++ }
action copy_b1 { b1 = string(buf[0:amt]); amt = 0 }
action copy_b2 { b2 = string(buf[0:amt]); amt = 0 }
action copy_host { url.Host = string(b1); amt = 0 }
action copy_port {
if b2 != "" {
url.Port, err = strconv.Atoi(string(b2))
if err != nil { goto fail }
if url.Port > 65535 { goto fail }
}
}
action params {
url.Params = string(data[mark:p])
}
action params_eof {
url.Params = string(data[mark:p])
return nil
}
action atsymbol {
url.User = string(b1)
url.Pass = string(b2)
b2 = ""
}
action alldone {
url.Host = string(b1)
if url.Host == "" {
url.Host = string(buf[0:amt])
} else {
if amt > 0 {
b2 = string(buf[0:amt])
}
if b2 != "" {
url.Port, err = strconv.Atoi(string(b2))
if err != nil { goto fail }
if url.Port > 65535 { goto fail }
}
}
return nil
}
# define what a single character is allowed to be
toxic = ( cntrl | 127 ) ;
scary = ( toxic | space | "\"" | "#" | "%" | "<" | ">" ) ;
authdelims = ( "/" | "?" | "#" | ":" | "@" | ";" | "[" | "]" ) ;
userchars = any -- ( authdelims | scary ) ;
userchars_esc = userchars | ":" ;
passchars = userchars ;
hostchars = passchars | "@" ;
hostchars_esc = hostchars | ":" ;
portchars = digit ;
paramchars = hostchars | ":" | ";" ;
# define how characters trigger actions
escape = "%" xdigit xdigit ;
unescape = "%" ( xdigit @hex_hi ) ( xdigit @hex_lo ) ;
userchar = unescape | ( userchars @str_char ) ;
userchar_esc = unescape | ( userchars_esc @str_char ) ;
passchar = unescape | ( passchars @str_char ) ;
hostchar = unescape | ( hostchars @str_char ) ;
hostchar_esc = unescape | ( hostchars_esc @str_char ) ;
portchar = unescape | ( portchars @str_char ) ;
paramchar = escape | paramchars ;
# define multi-character patterns
user_plain = userchar+ >str_start %copy_b1 ;
user_quoted = "[" ( userchar_esc+ >str_start %copy_b1 ) "]" ;
user = ( user_quoted | user_plain ) %/alldone ;
pass = passchar+ >str_start %copy_b2 %/alldone ;
host_plain = hostchar+ >str_start %copy_b1 %copy_host ;
host_quoted = "[" ( hostchar_esc+ >str_start %copy_b1 %copy_host ) "]" ;
host = ( host_quoted | host_plain ) %/alldone ;
port = portchar* >str_start %copy_b2 %copy_port %/alldone ;
params = ";" ( paramchar* >mark %params %/params_eof ) ;
userpass = user ( ":" pass )? ;
hostport = host ( ":" port )? ;
authority = ( userpass ( "@" @atsymbol ) )? hostport params? ;
main := authority;
write init;
write exec;
}%%
// if cs >= url_authority_first_final {
// return nil
// }
fail:
// fmt.Println("error state", cs)
// fmt.Println(string(data))
// for i := 0; i < p; i++ {
// fmt.Print(" ")
// }
// fmt.Println("^")
// fmt.Println(url)
return errors.New(fmt.Sprintf("bad url authority: %#v", string(data)))
}
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