rfc520.txt

著名的RFC文档,其中有一些文档是已经翻译成中文的的.


RFC 520      A Proposed File Access Protocol Specification  25 June 1973


   from server to user; write, from user to server; and both implies
   connections each ways.  Functionally, this command corresponds to
   RETR or STOR.  Therefore, all the FTP parameter commands (TYPE, MODE,
   etc.)  must be sent before the file is opened.  If the direction is
   write (W) and the file specified by the pathname does not exist,
   there is an implied create with the open.  The success of this
   create, is, of course, dependent on local access privileges and
   possibly whether or not an ALL command was sent.  If applicable, the
   file created should be of the most general kind of file on which
   "random" access is allowed. (This is to allow the largest degree of
   compatibility with operations that may follow).  This should be
   ignored if some site specific command has already specified the kind
   of file.  This command identifies the file on which subsequent
   operations are to be performed.  After the file is opened, the file
   pointer is at B and any of the other five FAP commands may be sent.
   It is acknowledged that some systems cannot open a file for access in
   both directions; an error reply 402 should be sent for this response.

   Replies
   -------
   258      451       500       504       550
   402      454       501       505
   434      455       502       506
   4550     457       503       507

III.2.2 SETP <argument>

   This command causes the file pointer to be set to the number
   specified in the argument.  This value will be the ordinal number of
   the starting position of the next operation. (Byte 0 is the first
   byte in the file).  The argument may take on two other values besides
   <decimal number> : B, for BEGIN, which sets the file pointer at the
   beginning of a file (i.e. 0) and E, for END, which sets the file
   pointer to the last byte in the file.  Two error conditions are
   possible.  If the argument specifies an illegal change of file
   pointer (such as moving it backwards on some systems), then the error
   reply 402 should be sent.  If the argument attempts to move the file
   pointer off the end of the file, then the EOF: <byte number> reply
   should be sent with the address of the end of the file (E), and the
   file pointer left at E.

   Replies
   -------
   258
   402
   480





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RFC 520      A Proposed File Access Protocol Specification  25 June 1973


III.2.3 GETP

   This command requests the server to return the value of the file
   pointer as a decimal number.

   Reply
   -----
   483
   504

III.2.4 READ <arg>

   This command instructs the server to move as many bytes as specified
   (of size logical byte size) from the server to the user.  The values
   the argument may take on are <decimal number> and ALL.  ALL is
   interpreted as all data from the present position of the file pointer
   to the end-of-file.  If a read requests more bytes than in the file,
   the number of bytes from the present position to the end of file
   should be transferred and an EOF: <byte number> response returned
   noting the position of the end of file.  If the file is Record
   structured and a READ requests more bytes than in the record, then
   the number of bytes in the record from the file pointer are moved and
   the EOR: <byte number> reply is sent noting the end of record.  The
   action of a READ leaves the file pointer at the position before the
   read plus the number of bytes moved, (i.e., updated).  The EOF
   condition leaves it at E.

   Replies
   -------
   258      480
   402      481
   450      482
   452      500-507
   455

III.2.5 WRITe <arg>

   This command instructs the server to accept as many bytes as
   specified from the user.  The result updates the value of the file
   pointer.  The values the argument may take on are <decimal number> or
   ALL.  ALL is interpreted as all data from the present position of the
   byte pointer to the end-of-file (or beyond).  Associated with the
   write is an implied "append", if necessary previous information has
   been sent (such as allocation) and if the file's access privilege
   allow the append.  If a write specifies more bytes than there are
   between the file pointer and the end-of-file, and expansion is not
   allowed, no data is sent and the file pointer is not moved.  An error
   is returned specifying the byte position of the EOF.  If the file is



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RFC 520      A Proposed File Access Protocol Specification  25 June 1973


   Record structured and a WRIT attempts to move more bytes than there
   are in the record, the file pointer is not moved and the EOR: <byte
   number> reply is sent noting the end of record.

   Replies
   -------
   258      480
   402      481
   450      482
   452      500-507
   453

III.2.6 CLOS

   This command instructs the server to "close" the presently open file,
   if any.  The receipt of a CLOS without an open file is not an error.
   The effect is to notify the server that further operations are not
   directed at the file which is presently open.  If an open is received
   by the server and it has a file open, it should close the open file
   and open the new one.

   Reply
   -----
   258

IV.  SUMMARY

IV.1 SYNTAX

   OPEN <direction> <pathname> CRLF
   CLOS CRLF
   SETP <byte pointer arg> CRLF
   GETP CRLF
   READ <transfer argument> CRLF
   WRIT <transfer argument> CRLF

   <direction>::= R|W|B

   <byte pointer argument>::= B|E|<decimal number>

   <transfer argument>::=ALL|<decimal number>

   <byte number>::= <decimal number>








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RFC 520      A Proposed File Access Protocol Specification  25 June 1973


IV.2 REPLIES USED BY FAP

   258    Operation successful
   402    Command not implemented for requested value or action
   433    Cannot transfer files w/o valid account. Enter account &
          resend command.
   450    FTP: file not found
   451    FTP: file access denied
   452    FTP: file transfer incomplete, data connection closed.
   453    FTP: file transfer incomplete, insufficient storage space.
   454    FTP: cannot connect to your data socket
   455    FTP: file system error not covered by other reply codes.
   457    FTP: transfer parameters in error.
   480    EOR: <byte number>
   481    EOF: <byte number>
   482    File not open for operation
   483    FP: <byte pointer>
   500    Last command line completely unrecognized.
   501    Syntax of last command is incorrect.
   502    Last command invalid (ignored), illegal parameter combination.
   504    Last command invalid, action not possible at this time.
   505    Last command conflicts illegally with previous command(s).
   506    Last command not implemented by the server.
   507    Catchall error reply.
   550    Bad pathname specification (e.g., syntax error).


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Day                                                             [Page 8]