rfc1738.txt

很多RFC的中文文档

fpath          = fsegment *[ "/" fsegment ]
fsegment       = *[ uchar | "?" | ":" | "@" | "&" | "=" ]
ftptype        = "A" | "I" | "D" | "a" | "i" | "d"
;FILE(文件)
fileurl        = "file://" [ host | "localhost" ] "/" fpath
;HTTP(超文本传输协议)
httpurl        = "http://" hostport [ "/" hpath [ "?" search ]]
hpath          = hsegment *[ "/" hsegment ]
hsegment       = *[ uchar | ";" | ":" | "@" | "&" | "=" ]
search         = *[ uchar | ";" | ":" | "@" | "&" | "=" ]
;GOPHER(请参考RFC1436)
gopherurl      = "gopher://" hostport [ / [ gtype [ selector
                 [ "%09" search [ "%09" gopher+_string ] ] ] ] ]
gtype          = xchar
selector       = *xchar
gopher+_string = *xchar
;MAILTO(请参考RFC822)
mailtourl      = "mailto:" encoded822addr
encoded822addr = 1*xchar               ;在RFC822中进一步定义了
;NEWS（新闻,请参考RFC1036）
newsurl        = "news:" grouppart
grouppart      = "*" | group | article
group          = alpha *[ alpha | digit | "-" | "." | "+" | "_" ]
article        = 1*[ uchar | ";" | "/" | "?" | ":" | "&" | "=" ] "@" host
;NNTP（网络新闻传输协议,请参考RFC977）
nntpurl        = "nntp://" hostport "/" group [ "/" digits ]
;TELNET(远程登录协议)
telneturl      = "telnet://" login [ "/" ]
;WAIS(广域信息服务系统，请参考RFC1625)
waisurl        = waisdatabase | waisindex | waisdoc
waisdatabase   = "wais://" hostport "/" database
waisindex      = "wais://" hostport "/" database "?" search
waisdoc        = "wais://" hostport "/" database "/" wtype "/" wpath
database       = *uchar
wtype          = *uchar
wpath          = *uchar
;PROSPERO
prosperourl    = "prospero://" hostport "/" ppath *[ fieldspec ]
ppath          = psegment *[ "/" psegment ]
psegment       = *[ uchar | "?" | ":" | "@" | "&" | "=" ]
fieldspec      = ";" fieldname "=" fieldvalue
fieldname      = *[ uchar | "?" | ":" | "@" | "&" ]
fieldvalue     = *[ uchar | "?" | ":" | "@" | "&" ]
;杂七杂八的定义
lowalpha       = "a" | "b" | "c" | "d" | "e" | "f" | "g" | "h" |
                 "i" | "j" | "k" | "l" | "m" | "n" | "o" | "p" |
                 "q" | "r" | "s" | "t" | "u" | "v" | "w" | "x" |
                 "y" | "z"
hialpha        = "A" | "B" | "C" | "D" | "E" | "F" | "G" | "H" | "I" |
                 "J" | "K" | "L" | "M" | "N" | "O" | "P" | "Q" | "R" |
                 "S" | "T" | "U" | "V" | "W" | "X" | "Y" | "Z"
alpha          = lowalpha | hialpha
digit          = "0" | "1" | "2" | "3" | "4" | "5" | "6" | "7" |
                 "8" | "9"
safe           = "$" | "-" | "_" | "." | "+"
extra          = "!" | "*" | "'" | "(" | ")" | ","
national       = "{" | "}" | "|" | "\" | "^" | "~" | "[" | "]" | "`"
punctuation    = "<" | ">" | "#" | "%" | <">


reserved       = ";" | "/" | "?" | ":" | "@" | "&" | "="
hex            = digit | "A" | "B" | "C" | "D" | "E" | "F" |
                 "a" | "b" | "c" | "d" | "e" | "f"
escape         = "%" hex hex

unreserved     = alpha | digit | safe | extra
uchar          = unreserved | escape
xchar          = unreserved | reserved | escape
digits         = 1*digit

6．安全事项
URL方案自身并不会造成安全威胁。用户需要小心的是：在一个时刻指向一个给定对象的
URL并不会保证一直指向这个对象。甚至也不保证因服务器上对象的移动而会在后来指向
另一个不同的对象。
一种同URL相关的安全威胁是：构建一个试图执行像取回对象这样无害的等幂操作的URL
有时可能会导致发生破坏性的远程操作。这个不安全的URL通常是通过指定一个除了那
些保留给正在讨论的网络协议用的端口数产生的。客户端在无意间同一个服务器打了交
道，而这个服务器实际上正在运行一个不同的协议，这样就导致URL内容中包含的指令
被其他的协议解释了，从而产生意外操作。一个例子就是使用gopher URL来生成一个原
始的消息并通过SMTP服务器来发送。在使用那些指定端口不是缺省端口的URL时应该进
行警告，尤其是在这个端口数出现在保留空间里面的情况下。
当URL包含有嵌入式已编码的特定协议中的分隔符（例如，telnet协议的CR和LF字符）
并且在传输前没有被解码时应该引起注意。这样除了可能被用来模拟一个超出其范围的操
作或者参数，会干扰这个协议，并再一次引起执行意想不到的而且可能是有害的远程操作。
使用包含应该作为秘密的密码的URL是非常轻率的。
7．感谢
这份文件建立在基本WWW设计（RFC1630）和许多人在网络上对这个观点进行的诸多讨论
的基础上。这些讨论受到了Clifford Lynch，Brewster Kahle [10] 和 Wengyik Yeong 
[18]的文章的极大鼓舞。这份文件综合了John Curran, Clifford Neuman, Ed Vielmetti
和后来的IETF URL BOF与URI工作小组的成果。

Dan Connolly, Ned Freed, Roy Fielding, Guido van Rossum, Michael Dolan, Bert 
Bos, John Kunze, Olle Jarnefors, Peter Svanberg最近详细审阅了这份文件并提出
了宝贵的意见。还有许多人为这份RFC的完善提供了很大帮助。

附录：上下文URL的推荐标准
URI（统一资源标志符），包括URL，趋向于通过这样的协议来传输：这些协议为它们的解
释提供了上下文。
在有些情况下，有必要区分URL和语法结构中其他可能的数据结构。在这种情况下，建
议在URL之前加上一个有字符“URL:”组成的前缀，这个前缀可以用来把URL和其它种
类的URI区分开。

此外，其它种类的文字中包含URL的情况也很常见。例如包含在电子邮件中，USENET 新
闻消息中或者印在纸上。在这些情况下，可以很方便的用一个单独的语法分隔符号来分隔
URL并把它和文字的其它部分相分离。在一些特殊情况下，标点符号标记可能会造成URL
的其它部分出错。因为这个原因，建议使用尖括号（“<”和“>”）并使用“URL:”前缀
来界定URL。这些界定符号不会出现在URL中，也不应该出现在指定这个界定符的上下文
中。
在一个“片断/锚点”（fragment/anchor）标志符和一个URL（在一个“#”之后）相关联
的情况下，这个标志符也应该放到括号中。
在有些情况下，需要加一些额外的空白（空格，回车，制表符等）来打断那些超过一行的
长URL。在提取URL时这些空白应该被忽略。
在连字符（“-”）后不应该加入空白。因为有些排字机和打印机在打断一行是可能会（错
误地）在行末加入一个连字符，解释程序在解释一个在连字符后包含一个行中断的URL
时应该忽略行中断左右所有未编码的空白,并且应该注意到连字符可能是也可能不是URL
的一个部分。
例如：
是的，Jim，我发现它在<URL:ftp://info.cern.ch/pub/www/doc;type=d>上，但是你可
能能够从<URL:ftp://ds.internic.net/rfc>那儿获得它。请注意
<URL:http://ds.internic.net/instructions/overview.html#WARNING>上的警告。

参考文献：
   [1] Anklesaria, F., McCahill, M., Lindner, P., Johnson, D.,
       Torrey, D., and B. Alberti, "The Internet Gopher Protocol
       (a distributed document search and retrieval protocol)",
       RFC 1436, University of Minnesota, March 1993.
       <URL:ftp://ds.internic.net/rfc/rfc1436.txt;type=a>

   [2] Anklesaria, F., Lindner, P., McCahill, M., Torrey, D.,
       Johnson, D., and B. Alberti, "Gopher+: Upward compatible
       enhancements to the Internet Gopher protocol",
       University of Minnesota, July 1993.
       <URL:ftp://boombox.micro.umn.edu/pub/gopher/gopher_protocol
       /Gopher+/Gopher+.txt>

   [3] Berners-Lee, T., "Universal Resource Identifiers in WWW: A
       Unifying Syntax for the Expression of Names and Addresses of
       Objects on the Network as used in the World-Wide Web", RFC
       1630, CERN, June 1994.
       <URL:ftp://ds.internic.net/rfc/rfc1630.txt>

   [4] Berners-Lee, T., "Hypertext Transfer Protocol (HTTP)",
       CERN, November 1993.
       <URL:ftp://info.cern.ch/pub/www/doc/http-spec.txt.Z>

   [5] Braden, R., Editor, "Requirements for Internet Hosts --
       Application and Support", STD 3, RFC 1123, IETF, October 1989.
       <URL:ftp://ds.internic.net/rfc/rfc1123.txt>

   [6] Crocker, D. "Standard for the Format of ARPA Internet Text
       Messages", STD 11, RFC 822, UDEL, April 1982.
       <URL:ftp://ds.internic.net/rfc/rfc822.txt>

   [7] Davis, F., Kahle, B., Morris, H., Salem, J., Shen, T., Wang, R.,
       Sui, J., and M. Grinbaum, "WAIS Interface Protocol Prototype
       Functional Specification", (v1.5), Thinking Machines
       Corporation, April 1990.
       <URL:ftp://quake.think.com/pub/wais/doc/protspec.txt>

   [8] Horton, M. and R. Adams, "Standard For Interchange of USENET
       Messages", RFC 1036, AT&T Bell Laboratories, Center for Seismic
       Studies, December 1987.
       <URL:ftp://ds.internic.net/rfc/rfc1036.txt>

   [9] Huitema, C., "Naming: Strategies and Techniques", Computer
       Networks and ISDN Systems 23 (1991) 107-110.
  [10] Kahle, B., "Document Identifiers, or International Standard
       Book Numbers for the Electronic Age", 1991.
       <URL:ftp://quake.think.com/pub/wais/doc/doc-ids.txt>

  [11] Kantor, B. and P. Lapsley, "Network News Transfer Protocol:
       A Proposed Standard for the Stream-Based Transmission of News",
       RFC 977, UC San Diego & UC Berkeley, February 1986.
       <URL:ftp://ds.internic.net/rfc/rfc977.txt>

  [12] Kunze, J., "Functional Requirements for Internet Resource
       Locators", Work in Progress, December 1994.
       <URL:ftp://ds.internic.net/internet-drafts
       /draft-ietf-uri-irl-fun-req-02.txt>

  [13] Mockapetris, P., "Domain Names - Concepts and Facilities",
       STD 13, RFC 1034, USC/Information Sciences Institute,
       November 1987.
       <URL:ftp://ds.internic.net/rfc/rfc1034.txt>

  [14] Neuman, B., and S. Augart, "The Prospero Protocol",
       USC/Information Sciences Institute, June 1993.
       <URL:ftp://prospero.isi.edu/pub/prospero/doc
       /prospero-protocol.PS.Z>

  [15] Postel, J. and J. Reynolds, "File Transfer Protocol (FTP)",
       STD 9, RFC 959, USC/Information Sciences Institute,
       October 1985.
       <URL:ftp://ds.internic.net/rfc/rfc959.txt>

  [16] Sollins, K. and L. Masinter, "Functional Requirements for
       Uniform Resource Names", RFC 1737, MIT/LCS, Xerox Corporation,
       December 1994.
       <URL:ftp://ds.internic.net/rfc/rfc1737.txt>

  [17] St. Pierre, M, Fullton, J., Gamiel, K., Goldman, J., Kahle, B.,
       Kunze, J., Morris, H., and F. Schiettecatte, "WAIS over
       Z39.50-1988", RFC 1625, WAIS, Inc., CNIDR, Thinking Machines
       Corp., UC Berkeley, FS Consulting, June 1994.
       <URL:ftp://ds.internic.net/rfc/rfc1625.txt>

  [18] Yeong, W. "Towards Networked Information Retrieval", Technical
       report 91-06-25-01, Performance Systems International, Inc.
       <URL:ftp://uu.psi.com/wp/nir.txt>, June 1991.

  [19] Yeong, W., "Representing Public Archives in the Directory",
       Work in Progress, November 1991.

  [20] "Coded Character Set -- 7-bit American Standard Code for
       Information Interchange", ANSI X3.4-1986.

编者地址：
Tim Berners-Lee
World-Wide Web project
CERN,
1211 Geneva 23,
Switzerland

电话：[phone]
传真：[phone]
Email：[e-mail]

Larry Masinter
Xerox PARC
3333 Coyote Hill Road
Palo Alto, CA 94034

电话: [phone]
传真: [phone]
EMail: [e-mail]


Mark McCahill
Computer and Information Services,
University of Minnesota
Room 152 Shepherd Labs
100 Union Street SE
Minneapolis, MN 55455

电话: [phone]
EMail: [e-mail]



RFC1738——Uniform Resource Locators (URL)             统一资源定位器（URL）


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RFC文档中文翻译计划