GNU Wget Metalink module (--input-metalink)

  Evaluation of "Directory Options" on the command line


1. Introduction
***************

This document, and the results contained in it, is focused over the
testing of the metalink:file "path/file" name format.

The "Directory Options" mentioned here are used on the command line in
conjunction with the option '--input-metalink=file':

$ wget --input-metalink=file <directory options>

2. Notes
********

Tests containing a metalink:file "/path/file", "./path/file", or
"../path/file" name shall be run manually due to security concerns.

3. Metalink files used as reference
***********************************

3.1 Test: metalink:file with "path/file" name format
====================================================

cat > test.meta4 << EOF
<?xml version="1.0" encoding="UTF-8"?>
<metalink xmlns="urn:ietf:params:xml:ns:metalink">
  <file name="path/file">
    <size>543</size>
    <hash type="sha256">d37d3965f8e1a7b16504b4273b09c392776b7e4dd17e601256c7b2fd9ce5f56e</hash>
    <hash type="md5">0f6ff5cdc15603f1b81227b5a296f001</hash>
    <url>http://wrongurl.really/gnu/wget/wget-1.18.tar.xz.sig</url>
    <url>http://ftpmirror.gnu.org/wget/wget-1.18.tar.xz.sig</url>
    <url>http://ftp.gnu.org/gnu/wget/wget-1.18.tar.xz.sig</url>
    <url>http://nl.mirror.babylon.network/gnu/wget/wget-1.18.tar.xz.sig</url>
  </file>
</metalink>
EOF

4. `wget --input-metalink=test.meta4`
*************************************

4.1 Implemented safety features
===============================

Do not follow relative or absolute paths: "/path/file", "./path/file",
and "../path/file" as metalink:file name formats are all ignored (wget
refuses to start). The options --trust-server-names changes nothing.

4.2 Actual behaviour
====================

Given a metalink:file "path/file" name, if "path" exists, download
"path/file", then compute its checksum. If "path" doesn't exist,
download the url's file in the working directory; then the checksum
fails: cannot find "path/file".

4.3 Questionable behaviours
===========================

If more metalink:file elements are the same, wget downloads them all.

4.4 Bugs
========

The download is OK even when metalink:file size is wrong.

5. Directory Options
********************

'-nd'
'--no-directories'

    Used alone has no effect (see `wget --input-metalink=test.meta4`).

    Used in conjunction with --recursive, given "path/file", if "path"
    exists, download "path/file" and compute its checksum.  If "path"
    doesnt' exist, download the url's file in the working directory,
    then the checksum fails: cannot find "path/file".

'-x'
'--force-directories'

    Given "path/file", if "path" exists, download "path/file", then
    compute its checksum.  If "path" doesn't exist, create the url
    hierarchy, then the checksum fails: cannot find "path/file".

'-nH'
'--no-host-directories'

    Given "path/file", if "path" exists, download "path/file", then
    compute its checksum.  If "path" doesn't exist, download the url's
    file in the working directory, then the checksum fails: cannot
    find "path/file"; in this context, if --force-directories is
    present, create the url hierarchy omitting the host component.

'--protocol-directories'

    Used alone has no effect (see `wget --input-metalink=test.meta4`).

    In conjunction with --force-directories, use the protocol name as
    the first directory component (see --force-directories).

'--cut-dirs=number'

    Used alone has no effect (see `wget --input-metalink=test.meta4`).

    In conjunction with --force-directories, ignore 'number' directory
    components after the domain (see --force-directories).

'-P prefix'
'--directory-prefix=prefix'

    This is buggy or non-intuitive.

    Given "path/file", and more metalink:url uris for the same file,
    if '-P path' is specified, the first url's file is downloaded as
    "path/<url_file>", and the second url's file as "path/file". The
    first file fails the checksum: cannot find "path/file". The file
    "path/file" passes the checksum verification.

    Given "path/file", and more metalink:url uris for the same file,
    if '-P newp' is specified, all the urls' files are downloaded as
    "newp/<url_file>. A suffix counter is added to the file names to
    not overwrite existing files. Then all the checksums fail: cannot
    find "path/file".

    Given "path/file", and more metalink:url uris for the same file,
    if '-P ../path' is specified, the same things as if '-P ../newp'
    or '-P newp' will happen, e.g. "newp/<url_file> and checksums
    failures.

    [write here more wrong things happening]