Tatsuhiro Tsujikawa
t-tujikawa_at_users_dot_sourceforge_dot_net
This program comes with no warranty. You must use this program at your own risk.
aria2 is a utility for downloading files. The supported protocols are HTTP(S), FTP, BitTorrent, and Metalink. aria2 can download a file from multiple sources/protocols and tries to utilize your maximum download bandwidth. It supports downloading a file from HTTP(S)/FTP and BitTorrent at the same time, while the data downloaded from HTTP(S)/FTP is uploaded to the BitTorrent swarm. Using Metalink’s chunk checksums, aria2 automatically validates chunks of data while downloading a file like BitTorrent.
The project page is located at http://aria2.sourceforge.net/.
See aria2 Online Manual (Russian translation, Portuguese translation) and the usage examples to learn how to use aria2.
Here is a list of features:
Command-line interface
Download files through HTTP(S)/FTP/BitTorrent
Segmented downloading
Metalink version 4 (RFC 5854) support(HTTP/FTP/BitTorrent)
Metalink version 3.0 support(HTTP/FTP/BitTorrent)
Metalink/HTTP (RFC 6249) support
HTTP/1.1 implementation
HTTP Proxy support
HTTP BASIC authentication support
HTTP Proxy authentication support
Well-known environment variables for proxy: http_proxy
, https_proxy
,
ftp_proxy
, all_proxy
and no_proxy
HTTP gzip, deflate content encoding support
Verify peer using given trusted CA certificate in HTTPS
Client certificate authentication in HTTPS
Chunked transfer encoding support
Load Cookies from file using the Firefox3 format, Chromium/Google Chrome and the Mozilla/Firefox (1.x/2.x)/Netscape format.
Save Cookies in the Mozilla/Firefox (1.x/2.x)/Netscape format.
Custom HTTP Header support
Persistent Connections support
FTP through HTTP Proxy
Download/Upload speed throttling
BitTorrent extensions: Fast extension, DHT, PEX, MSE/PSE, Multi-Tracker, UDP tracker
BitTorrent WEB-Seeding. aria2 requests chunks more than piece size to reduce the request overhead. It also supports pipelined requests with piece size.
BitTorrent Local Peer Discovery
Rename/change the directory structure of BitTorrent downloads completely
JSON-RPC (over HTTP and WebSocket)/XML-RPC interface
Run as a daemon process
Selective download in multi-file torrent/Metalink
Chunk checksum validation in Metalink
Can disable segmented downloading in Metalink
Netrc support
Configuration file support
Download URIs found in a text file or stdin and the destination directory and output filename can be specified optionally
Parameterized URI support
IPv6 support with Happy Eyeballs
Disk cache to reduce disk activity
We maintain the source code at Github: https://github.com/tatsuhiro-t/aria2
To get the latest source code, run following command:
$ git clone git://github.com/tatsuhiro-t/aria2.git
This will create aria2 directory in your current directory and source files are stored there.
features |
dependency |
---|---|
HTTPS |
GnuTLS or OpenSSL |
BitTorrent |
libnettle+libgmp or libgcrypt or OpenSSL |
Metalink |
libxml2 or Expat. |
Checksum |
libnettle or libgcrypt or OpenSSL |
gzip, deflate in HTTP |
zlib |
Async DNS |
C-Ares |
Firefox3/Chromium cookie |
libsqlite3 |
XML-RPC |
libxml2 or Expat. |
JSON-RPC over WebSocket |
libnettle or libgcrypt or OpenSSL |
Note
libxml2 has precedence over Expat if both libraries are installed.
If you prefer Expat, run configure with --without-libxml2
.
Note
GnuTLS has precedence over OpenSSL if both libraries are installed.
If you prefer OpenSSL, run configure with --without-gnutls
--with-openssl
.
Note
libnettle has precedence over libgcrypt if both libraries are
installed. If you prefer libgcrypt, run configure with
--without-libnettle --with-libgcrypt
. If OpenSSL is selected over
GnuTLS, neither libnettle nor libgcrypt will be used.
A user can have one of the following configurations for SSL and crypto libraries:
libgcrypt
libnettle
OpenSSL
GnuTLS + libgcrypt
GnuTLS + libnettle
You can disable BitTorrent and Metalink support by providing
--disable-bittorrent
and --disable-metalink
to the configure
script respectively.
In order to enable async DNS support, you need c-ares.
aria2 is primarily written in C++. Initially it was written based on
C++98/C++03 standard features. We are now migrating aria2 to C++11
standard. The current source code requires C++11 aware compiler. For
well-known compilers, such as g++ and clang, flag -std=c++11
or
-std=c++0x
must be supported.
In order to build aria2 from the source package, you need following development packages(package name may vary depending on the distribution you use):
libgnutls-dev (Required for HTTPS, BitTorrent, Checksum support)
nettle-dev (Required for BitTorrent, Checksum support)
libgmp-dev (Required for BitTorrent)
libc-ares-dev (Required for async DNS support)
libxml2-dev (Required for Metalink support)
zlib1g-dev (Required for gzip, deflate decoding support in HTTP)
libsqlite3-dev (Required for Firefox3/Chromium cookie support)
pkg-config (Required to detect installed libraries)
You can use libgcrypt-dev instead of nettle-dev and libgmp-dev:
libgpg-error-dev (Required for BitTorrent, Checksum support)
libgcrypt-dev (Required for BitTorrent, Checksum support)
You can use libssl-dev instead of libgnutls-dev, nettle-dev, libgmp-dev, libgpg-error-dev and libgcrypt-dev:
libssl-dev (Required for HTTPS, BitTorrent, Checksum support)
You can use libexpat1-dev instead of libxml2-dev:
libexpat1-dev (Required for Metalink support)
On Fedora you need the following packages: gcc, gcc-c++, kernel-devel, libgcrypt-devel, libgcrypt-devel, libxml2-devel, openssl-devel, gettext-devel, cppunit
If you downloaded source code from git repository, you have to run following command to generate configure script and other files necessary to build the program:
$ autoreconf -i
Also you need Sphinx to build man page.
If you are building aria2 for Mac OS X, take a look at build_osx_release.sh, which builds OSX universal binary DMG.
The quickest way to build aria2 is first run configure script:
$ ./configure
To build statically linked aria2, use ARIA2_STATIC=yes
command-line option:
$ ./configure ARIA2_STATIC=yes
After configuration is done, run make
to compile the program:
$ make
See Cross-compiling Windows binary to create Windows binary. See Cross-compiling Android binary to create Android binary.
The configure script checks available libraries and enables the features as much as possible because all the features are enabled by default.
Since 1.1.0, aria2 checks the certificate of HTTPS servers by default.
If you build with OpenSSL or the recent version of GnuTLS which has
gnutls_certificate_set_x509_system_trust()
function and the
library is properly configured to locate the system-wide CA
certificates store, aria2 will automatically load those certificates
at the startup. If it is not the case, I recommend to supply the path
to the CA bundle file. For example, in Debian the path to CA bundle
file is ‘/etc/ssl/certs/ca-certificates.crt’ (in ca-certificates
package). This may vary depending on your distribution. You can give
it to configure script using --with-ca-bundle option
:
$ ./configure --with-ca-bundle='/etc/ssl/certs/ca-certificates.crt'
$ make
Without --with-ca-bundle
option, you will encounter the error when
accessing HTTPS servers because the certificate cannot be verified
without CA bundle. In such case, you can specify the CA bundle file
using aria2’s --ca-certificate
option. If you don’t have CA bundle
file installed, then the last resort is disable the certificate
validation using --check-certificate=false
.
By default, bash_completion file named aria2c
is installed to the
directory $prefix/share/doc/aria2/bash_completion
. To change the
install directory of the file, use --with-bashcompletiondir
option.
The executable is ‘aria2c’ in src directory.
aria2 uses CppUnit for automated unit testing. To run the unit test:
$ make check
In this section, we describe how to build Windows binary using mingw-w64 cross-compiler on Debian Linux.
Basically, after compiling and installing depended libraries, you can
do cross-compile just passing appropriate --host
option and
specifying CPPFLAGS
, LDFLAGS
and PKG_CONFIG_LIBDIR
variables to configure. For convenience and lowering our own
development cost, we provide easier way to configure the build
settings.
mingw-config
script is a configure script wrapper for mingw-w64.
We use it to create official Windows build. This script assumes
following libraries have been built for cross-compile:
c-ares
openssl
expat
sqlite3
zlib
cppunit
Some environment variables can be adjusted to change build settings:
HOST
cross-compile to build programs to run on HOST
. It defaults to
i686-w64-mingw32
. To build 64bit binary, specify
x86_64-w64-mingw32
.
PREFIX
Prefix to the directory where dependent libraries are installed. It
defaults to /usr/local/$HOST
. -I$PREFIX/include
will be
added to CPPFLAGS
. -L$PREFIX/lib
will be added to
LDFLAGS
. $PREFIX/lib/pkgconfig
will be set to
PKG_CONFIG_LIBDIR
.
For example, to build 64bit binary do this:
$ HOST=x86_64-w64-mingw32 ./mingw-config
In this section, we describe how to build Android binary using Android NDK cross-compiler on Debian Linux.
android-config
script is a configure script wrapper for Android
build. We use it to create official Android build. This script
assumes the following libraries have been built for cross-compile:
c-ares
openssl
expat
When building the above libraries, make sure that disable shared library and enable only static library. We are going to link those libraries statically.
We use zlib which comes with Android NDK, so we don’t have to build it by ourselves.
android-config
assumes the existence of $ANDROID_HOME
environment variable which must fulfill the following conditions:
Android NDK toolchain is installed under
$ANDROID_HOME/toolchain
. Refer to “3/ Invoking the compiler
(the easy way):” section in Android NDK
docs/STANDALONE-TOOLCHAIN.html
to install custom toolchain.
For example, to install toolchain under $ANDROID_HOME/toolchain
,
do this:
$NDK/build/tools/make-standalone-toolchain.sh --platform=android-9 --install-dir=$ANDROID_HOME/toolchain
You may need to add --system=linux-x86_64
to the above
command-line for x86_64 Linux host.
The dependant libraries must be installed under
$ANDROID_HOME/usr/local
.
Before running android-config
and android-make
,
$ANDOIRD_HOME
environment variable must be set to point to the
correct path.
After android-config
, run android-make
to compile sources.
Sphinx is used to build the
documentation. aria2 man pages will be build when you run make
if
they are not up-to-date. You can also build HTML version of aria2 man
page by make html
. The HTML version manual is also available at
online (Russian
translation,
Portuguese translation).
The filename of the downloaded file is determined as follows:
If “name” key is present in .torrent file, filename is the value of “name” key. Otherwise, filename is the basename of .torrent file appended by “.file”. For example, .torrent file is “test.torrrent”, then filename is “test.torrent.file”. The directory to store the downloaded file can be specified by -d option.
The complete directory/file structure mentioned in .torrent file is created. The directory to store the top directory of downloaded files can be specified by -d option.
Before download starts, a complete directory structure is created if
needed. By default, aria2 opens at most 100 files mentioned in
.torrent file, and directly writes to and reads from these files.
The number of files to open simultaneously can be controlled by
--bt-max-open-files
option.
aria2 supports mainline compatible DHT. By default, the routing table
for IPv4 DHT is saved to $HOME/.aria2/dht.dat
and the routing
table for IPv6 DHT is saved to $HOME/.aria2/dht6.dat
. aria2 uses
same port number to listen on for both IPv4 and IPv6 DHT.
UDP tracker support is enabled when IPv4 DHT is enabled. The port
number of UDP tracker is shared with DHT. Use --dht-listen-port
option to change the port number.
-o
option is used to change the filename of .torrent file itself,
not a filename of a file in .torrent file. For this purpose, use
--index-out
option instead.
The port numbers that aria2 uses by default are 6881-6999 for TCP and UDP.
aria2 doesn’t configure port-forwarding automatically. Please configure your router or firewall manually.
The maximum number of peers is 55. This limit may be exceeded when
download rate is low. This download rate can be adjusted using
--bt-request-peer-speed-limit
option.
As of release 0.10.0, aria2 stops sending request message after selective download completes.
The current implementation supports HTTP(S)/FTP/BitTorrent. The other P2P protocols are ignored. Both Metalink4 and Metalink version 3.0 documents are supported.
For checksum verification, md5, sha-1, sha-224, sha-256, sha-384 and sha-512 are supported. If multiple hash algorithms are provided, aria2 uses stronger one. If whole file checksum verification fails, aria2 doesn’t retry the download and just exits with non-zero return code.
The supported user preferences are version, language, location, protocol and os.
If chunk checksums are provided in Metalink file, aria2 automatically validates chunks of data during download. This behavior can be turned off by a command-line option.
If signature is included in a Metalink file, aria2 saves it as a file after the completion of the download. The filename is download filename + “.sig”. If same file already exists, the signature file is not saved.
In Metalink4, multi-file torrent could appear in metalink:metaurl element. Since aria2 cannot download 2 same torrents at the same time, aria2 groups files in metalink:file element which has same BitTorrent metaurl and downloads them from a single BitTorrent swarm. This is basically multi-file torrent download with file selection, so the adjacent files which is not in Metalink document but shares same piece with selected file are also created.
If relative URI is specified in metalink:url or metalink:metaurl
element, aria2 uses the URI of Metalink file as base URI to resolve
the relative URI. If relative URI is found in Metalink file which is
read from local disk, aria2 uses the value of --metalink-base-uri
option as base URI. If this option is not specified, the relative URI
will be ignored.
The current implementation only uses rel=duplicate links only. aria2
understands Digest header fields and check whether it matches the
digest value from other sources. If it differs, drop connection.
aria2 also uses this digest value to perform checksum verification
after download finished. aria2 recognizes geo value. To tell aria2
which location you prefer, you can use --metalink-location
option.
netrc support is enabled by default for HTTP(S)/FTP. To disable netrc support, specify -n command-line option. Your .netrc file should have correct permissions(600).
The WebSocket server embedded in aria2 implements the specification defined in RFC 6455. The supported protocol version is 13.
The libaria2 is a C++ library which offers aria2 functionality to the
client code. Currently, libaria2 is not built by default. To enable
libaria2, use --enable-libaria2
configure option. By default,
only the shared library is built. To build static library, use
--enable-static
configure option as well. See libaria2
documentation to know how to use API.