465 lines
12 KiB
Groff
465 lines
12 KiB
Groff
.\" Copyright (c) 1998 Dag-Erling Coïdan Smørgrav
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.\" All rights reserved.
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.\"
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.\" Redistribution and use in source and binary forms, with or without
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.\" modification, are permitted provided that the following conditions
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.\" are met:
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.\" 1. Redistributions of source code must retain the above copyright
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.\" notice, this list of conditions and the following disclaimer.
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.\" 2. Redistributions in binary form must reproduce the above copyright
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.\" notice, this list of conditions and the following disclaimer in the
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.\" documentation and/or other materials provided with the distribution.
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.\"
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.\" THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
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.\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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.\" ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
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.\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
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.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
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.\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
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.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
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.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
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.\" SUCH DAMAGE.
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.\"
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.\" $FreeBSD$
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.\"
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.Dd July 1, 1998
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.Dt FETCH 3
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.Os
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.Sh NAME
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.Nm fetchParseURL ,
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.Nm fetchFreeURL ,
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.Nm fetchGetURL ,
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.Nm fetchPutURL ,
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.Nm fetchStatURL ,
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.Nm fetchListURL ,
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.Nm fetchGet ,
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.Nm fetchPut ,
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.Nm fetchStat ,
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.Nm fetchList ,
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.Nm fetchGetFile ,
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.Nm fetchPutFile ,
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.Nm fetchStatFile ,
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.Nm fetchListFile ,
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.Nm fetchGetHTTP ,
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.Nm fetchPutHTTP ,
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.Nm fetchStatHTTP ,
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.Nm fetchListHTTP ,
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.Nm fetchGetFTP ,
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.Nm fetchPutFTP ,
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.Nm fetchStatFTP ,
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.Nm fetchListFTP
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.Nd file transfer functions
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.Sh LIBRARY
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.Lb libfetch
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.Sh SYNOPSIS
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.Fd #include <sys/param.h>
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.Fd #include <stdio.h>
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.Fd #include <fetch.h>
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.Ft struct url *
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.Fn fetchParseURL "char *URL"
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.Ft void
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.Fn fetchFreeURL "struct url *URL"
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.Ft FILE *
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.Fn fetchGetURL "char *URL" "char *flags"
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.Ft FILE *
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.Fn fetchPutURL "char *URL" "char *flags"
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.Ft int
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.Fn fetchStatURL "char *URL" "struct url_stat *us" "char *flags"
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.Ft struct url_ent *
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.Fn fetchListURL "char *URL" "char *flags"
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.Ft FILE *
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.Fn fetchGet "struct url *URL" "char *flags"
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.Ft FILE *
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.Fn fetchPut "struct url *URL" "char *flags"
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.Ft int
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.Fn fetchStat "struct url *URL" "struct url_stat *us" "char *flags"
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.Ft struct url_ent *
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.Fn fetchList "struct url *" "char *flags"
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.Ft FILE *
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.Fn fetchGetFile "struct url *u" "char *flags"
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.Ft FILE *
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.Fn fetchPutFile "struct url *u" "char *flags"
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.Ft int
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.Fn fetchStatFile "struct url *URL" "struct url_stat *us" "char *flags"
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.Ft struct url_ent *
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.Fn fetchListFile "struct url *" "char *flags"
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.Ft FILE *
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.Fn fetchGetHTTP "struct url *u" "char *flags"
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.Ft FILE *
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.Fn fetchPutHTTP "struct url *u" "char *flags"
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.Ft int
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.Fn fetchStatHTTP "struct url *URL" "struct url_stat *us" "char *flags"
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.Ft struct url_ent *
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.Fn fetchListHTTP "struct url *" "char *flags"
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.Ft FILE *
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.Fn fetchGetFTP "struct url *u" "char *flags"
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.Ft FILE *
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.Fn fetchPutFTP "struct url *u" "char *flags"
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.Ft int
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.Fn fetchStatFTP "struct url *URL" "struct url_stat *us" "char *flags"
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.Ft struct url_ent *
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.Fn fetchListFTP "struct url *" "char *flags"
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.Sh DESCRIPTION
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.Pp
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These functions implement a high-level library for retrieving and
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uploading files using Uniform Resource Locators (URLs).
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.Pp
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.Fn fetchParseURL
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takes a URL in the form of a null-terminated string and splits it into
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its components function according to the Common Internet Scheme Syntax
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detailed in RFC1738.
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A regular expression which produces this syntax is:
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.Bd -literal
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<scheme>:(//(<user>(:<pwd>)?@)?<host>(:<port>)?)?/(<document>)?
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.Ed
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.Pp
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Note that some components of the URL are not necessarily relevant to
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all URL schemes.
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For instance, the file scheme only needs the <scheme>
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and <document> components.
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.Pp
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The pointer returned by
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.Fn fetchParseURL
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should be freed using
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.Fn fetchFreeURL .
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.Pp
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.Fn fetchGetURL
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and
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.Fn fetchPutURL
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constitute the recommended interface to the
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.Nm fetch
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library.
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They examine the URL passed to them to determine the transfer
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method, and call the appropriate lower-level functions to perform the
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actual transfer.
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The
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.Fa flags
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argument is a string of characters which specify transfer options.
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The
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meaning of the individual flags is scheme-dependent, and is detailed
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in the appropriate section below.
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.Pp
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.Fn fetchStatURL
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attempts to obtain the requested document's metadata and fill in the
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structure pointed to by it's second argument.
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The
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.Fa url_stat
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structure is defined as follows in
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.Aq Pa fetch.h :
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.Bd -literal
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struct url_stat {
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off_t size;
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time_t atime;
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time_t mtime;
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};
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.Ed
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.Pp
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.Fn fetchListURL
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attempts to list the contents of the directory pointed to by the URL
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provided.
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If successful, it returns a malloced array of
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.Fa url_ent
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structures.
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The
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.Fa url_ent
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structure is defined as follows in
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.Aq Pa fetch.h :
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.Bd -literal
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struct url_ent {
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char name[MAXPATHLEN];
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struct url_stat stat;
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};
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.Ed
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.Pp
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The list is terminated by an entry with an empty name.
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.Pp
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The pointer returned by
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.Fn fetchListURL
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should be freed using
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.Fn free .
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.Pp
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.Fn fetchGet ,
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.Fn fetchPut
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and
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.Fn fetchStat
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are similar to
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.Fn fetchGetURL ,
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.Fn fetchPutURL
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and
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.Fn fetchStatURL ,
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except that they expect a pre-parsed URL in the form of a pointer to
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a
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.Fa struct url
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rather than a string.
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.Pp
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All of the
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.Fn fetchGetXXX
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and
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.Fn fetchPutXXX
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functions return a pointer to a stream which can be used to read or
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write data from or to the requested document, respectively.
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Note that
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although the implementation details of the individual access methods
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vary, it can generally be assumed that a stream returned by one of the
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.Fn fetchGetXXX
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functions is read-only, and that a stream returned by one of the
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.Fn fetchPutXXX
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functions is write-only.
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.Sh FILE SCHEME
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.Fn fetchGetFile
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and
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.Fn fetchPutFile
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provide access to documents which are files in a locally mounted file
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system.
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Only the <document> component of the URL is used.
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.Pp
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.Fn fetchGetFile
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does not accept any flags.
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.Pp
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.Fn fetchPutFile
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accepts the
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.Fa a
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(append to file) flag.
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If that flag is specified, the data written to
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the stream returned by
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.Fn fetchPutFile
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will be appended to the previous contents of the file, instead of
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replacing them.
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.Sh FTP SCHEME
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.Fn fetchGetFTP
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and
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.Fn fetchPutFTP
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implement the FTP protocol as described in RFC959.
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.Pp
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If the
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.Fa p
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(passive) flag is specified, a passive (rather than active) connection
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will be attempted.
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.Pp
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If the
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.Fa h
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(high) flag is specified, data sockets will be allocated in the high
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port range (see
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.Xr ip 4 ).
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.Pp
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If the
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.Fa d
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(direct) flag is specified,
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.Fn fetchGetFTP
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and
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.Fn fetchPutFTP
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will use a direct connection even if a proxy server is defined.
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.Pp
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If no user name or password is given, the
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.Nm fetch
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library will attempt an anonymous login, with user name "ftp" and
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password "ftp".
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.Sh HTTP SCHEME
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The
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.Fn fetchGetHTTP
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and
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.Fn fetchPutHTTP
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functions implement the HTTP/1.1 protocol.
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With a little luck, there's
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even a chance that they comply with RFC2068.
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.Pp
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If the
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.Fa d
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(direct) flag is specified,
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.Fn fetchGetHTTP
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and
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.Fn fetchPutHTTP
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will use a direct connection even if a proxy server is defined.
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.Pp
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Since there seems to be no good way of implementing the HTTP PUT
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method in a manner consistent with the rest of the
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.Nm fetch
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library,
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.Fn fetchPutHTTP
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is currently unimplemented.
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.Sh RETURN VALUES
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.Fn fetchParseURL
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returns a pointer to a
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.Fa struct url
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containing the individual components of the URL.
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If it is
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unable to allocate memory, or the URL is syntactically incorrect,
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.Fn fetchParseURL
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returns a NULL pointer.
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.Pp
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The
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.Fn fetchStat
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functions return 0 on success and -1 on failure.
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.Pp
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All other functions return a stream pointer which may be used to
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access the requested document, or NULL if an error occurred.
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.Pp
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.Nm Libfetch
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uses the Common Error Library
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.Nm ( libcom_err )
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to report errors.
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The error code passed to
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.Fn com_err
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is one of:
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.Bl -tag -width 18n
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.It Bq Er FETCH_ABORT
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Operation aborted
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.It Bq Er FETCH_AUTH
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Authentication failed
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.It Bq Er FETCH_DOWN
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Service unavailable
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.It Bq Er FETCH_EXISTS
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File exists
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.It Bq Er FETCH_FULL
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File system full
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.It Bq Er FETCH_INFO
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Informational response
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.It Bq Er FETCH_MEMORY
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Insufficient memory
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.It Bq Er FETCH_MOVED
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File has moved
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.It Bq Er FETCH_NETWORK
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Network error
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.It Bq Er FETCH_OK
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No error
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.It Bq Er FETCH_PROTO
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Protocol error
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.It Bq Er FETCH_RESOLV
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Resolver error
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.It Bq Er FETCH_SERVER
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Server error
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.It Bq Er FETCH_TEMP
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Temporary error
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.It Bq Er FETCH_TIMEOUT
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Operation timed out
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.It Bq Er FETCH_UNAVAIL
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File is not available
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.It Bq Er FETCH_UNKNOWN
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Unknown error
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.It Bq Er FETCH_URL
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Invalid URL
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.El
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.Pp
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The accompanying error message includes a protocol-specific error code
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and message, e.g. "File is not available (404 Not Found)"
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.Sh ENVIRONMENT
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The FTP and HTTP related functions use the
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.Ev HTTP_PROXY
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and
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.Ev FTP_PROXY
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environment variables, respectively, as the address of a proxy server
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to use for transferring files.
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.Sh SEE ALSO
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.Xr com_err 3 ,
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.Xr fetch 1 ,
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.Xr ftpio 3 ,
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.Xr ip 4 .
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.Rs
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.%A T. Berners-Lee
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.%A L. Masinter
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.%A M. McCahill
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.%D December 1994
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.%T Uniform Resource Locators (URL)
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.%O RFC1738
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.Re
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.Rs
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.%A R. Fielding
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.%A J. Gettys
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.%A J. Mogul
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.%A H. Frystyk
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.%A T. Berners-Lee
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.%D Januray 1997
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.%B Hypertext Transfer Protocol -- HTTP/1.1
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.%O RFC2068
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.Re
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.Rs
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.%A J. Postel
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.%A J. K. Reynolds
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.%D October 1985
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.%B File Transfer Protocol
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.%O RFC959
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.Re
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.Sh NOTES
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The
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.Nm fetch
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library uses the Common Error library, and applications which link
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with
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.Nm libfetch
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must therefore also link with
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.Nm libcom_err .
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.Sh HISTORY
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The
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.Nm fetch
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library first appeared in
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.Fx 3.0 .
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.Sh AUTHORS
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The
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.Nm fetch
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library was mostly written by
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.An Dag-Erling Coïdan Smørgrav Aq des@FreeBSD.org
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with numerous suggestions from
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.An Jordan K. Hubbard Aq jkh@FreeBSD.org ,
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.An Eugene Skepner Aq eu@qub.com
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and other FreeBSD developers.
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It replaces the older
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.Nm ftpio
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library written by
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.An Poul-Henning Kamp Aq pkh@FreeBSD.org
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and
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.An Jordan K. Hubbard Aq jkh@FreeBSD.org .
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.Pp
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This manual page was written by
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.An Dag-Erling Coïdan Smørgrav Aq des@FreeBSD.org
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.Sh BUGS
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Some parts of the library are not yet implemented.
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The most notable
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examples of this are
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.Fn fetchPutHTTP ,
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.Fn fetchListHTTP ,
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.Fn fetchListFTP
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and FTP proxy support.
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.Pp
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There's no way to select a proxy at run-time other than setting the
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.Ev HTTP_PROXY
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or
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.Ev FTP_PROXY
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environment variables as appropriate.
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There is also no way to stop the
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FTP and HTTP functions from trying to use a proxy if these variables
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are set.
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.Pp
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HTTP authentication doesn't work.
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I'm not sure that's a bug in my
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code; as far as I can determine,
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.Nm libfetch
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handles HTTP/1.1 basic authentication correctly as outlined in
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RFC2068, but I haven't been able to find an HTTP server that honors
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the Authentication: header field.
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Also,
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.Nm libfetch
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does not attempt to interpret and respond to authentication requests
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from the HTTP server.
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.Pp
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No attempt is made to encode spaces etc. within URLs.
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Spaces in the
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document part of an URLshould be replaced with "%20" in HTTP URLs and
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"\\ " in FTP URLs.
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.Pp
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Error numbers are unique only within a certain context; the error
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codes used for FTP and HTTP overlap, as do those used for resolver and
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system errors.
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For instance, error code 202 means "Command not
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implemented, superfluous at this site" in an FTP context and
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"Accepted" in an HTTP context.
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.Pp
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.Fn fetchStatFTP
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does not check that the result of an MDTM command is a valid date.
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.Pp
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The HTTP code needs a complete rewrite, or at least a serious cleanup.
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.Pp
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The man page is poorly written and produces badly formatted text.
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.Pp
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Tons of other stuff.
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