aria2 - The ultra fast download utility

Disclaimer

This program comes with no warranty. You must use this program at your own risk.

Introduction

aria2 is a utility for downloading files. The supported protocols are HTTP(S), FTP, SFTP, 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/SFTP and BitTorrent at the same time, while the data downloaded from HTTP(S)/FTP/SFTP 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 https://aria2.github.io/.

See the aria2 Online Manual <https://aria2.github.io/manual/en/html/>_ (Russian translation <https://aria2.github.io/manual/ru/html/>, Portuguese translation <https://aria2.github.io/manual/pt/html/>) to learn how to use aria2.

Features

Here is a list of features:

• Command-line interface
• Download files through HTTP(S)/FTP/SFTP/BitTorrent
• Segmented downloading
• Metalink version 4 (RFC 5854) support(HTTP/FTP/SFTP/BitTorrent)
• Metalink version 3.0 support(HTTP/FTP/SFTP/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 the 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/SFTP through HTTP Proxy
• Download/Upload speed throttling
• BitTorrent extensions: Fast extension, DHT, PEX, MSE/PSE, Multi-Tracker, UDP tracker
• BitTorrent WEB-Seeding <http://getright.com/seedtorrent.html>_. aria2 requests chunk 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 file name can be specified optionally
• Parameterized URI support
• IPv6 support with Happy Eyeballs
• Disk cache to reduce disk activity

Versioning and release schedule

We use 3 numbers for the aria2 version: MAJOR.MINOR.PATCH. We will ship MINOR updates on the 15th of every month. We may skip a release if we have had no changes since the last release. The feature and documentation freeze happens 10 days before the release day (the 5th day of the month) for translation teams. We will raise an issue about the upcoming release around that day.

We may release PATCH releases between regular releases if we have security issues.

The MAJOR version will stay at 1 for the time being.

How to get source code

We maintain the source code at Github: https://github.com/aria2/aria2

To get the latest source code, run the following command::

$ git clone https://github.com/aria2/aria2.git

This will create an aria2 directory in your current directory and source files are stored there.

Dependency

======================== ======================================== features dependency ======================== ======================================== HTTPS OSX or GnuTLS or OpenSSL or Windows SFTP libssh2 BitTorrent None. Optional: libnettle+libgmp or libgcrypt or OpenSSL (see note) Metalink libxml2 or Expat. Checksum None. Optional: OSX or libnettle or libgcrypt or OpenSSL or Windows (see note) 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::

On Apple OSX, OS-level SSL/TLS support will be preferred. Hence neither GnuTLS nor OpenSSL is required on that platform. If you'd like to disable this behavior, run configure with --without-appletls.

GnuTLS has precedence over OpenSSL if both libraries are installed. If you prefer OpenSSL, run configure with --without-gnutls --with-openssl.

On Windows, there is SSL implementation available that is based on the native Windows SSL capabilities (Schannel) and it will be preferred. Hence neither GnuTLS nor OpenSSL is required on that platform. If you'd like to disable this behavior, run configure with --without-wintls.

.. note::

On Apple OSX, the OS-level checksum support will be preferred, unless aria2 is configured with --without-appletls.

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.

If none of the optional dependencies are installed, an internal implementation that only supports md5 and sha1 will be used.

On Windows, there is SSL implementation available that is based on the native Windows capabilities and it will be preferred, unless aria2 is configured with --without-wintls.

A user can have one of the following configurations for SSL and crypto libraries:

• OpenSSL
• GnuTLS + libgcrypt
• GnuTLS + libnettle
• Apple TLS (OSX only)
• Windows TLS (Windows only)

You can disable BitTorrent and Metalink support by providing --disable-bittorrent and --disable-metalink to the configure script respectively.

To enable async DNS support, you need c-ares.

• c-ares: http://c-ares.haxx.se/

How to build

aria2 is primarily written in C++. Initially, it was written based on C++98/C++03 standard features. We are now migrating aria2 to the C++11 standard. The current source code requires a C++11 aware compiler. For well-known compilers, such as g++ and clang, the -std=c++11 or -std=c++0x flag must be supported.

To build aria2 from the source package, you need the 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)
• libssh2-1-dev (Required for SFTP support)
• 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, libxml2-devel, openssl-devel, gettext-devel, cppunit

If you downloaded source code from a git repository, you have to install the following packages to get autoconf macros:

• libxml2-dev
• libcppunit-dev
• autoconf
• automake
• autotools-dev
• autopoint
• libtool

And run the following command to generate configure script and other files necessary to build the program::

$ autoreconf -i

Also, you need Sphinx <http://sphinx-doc.org/>_ to build the man page.

If you are building aria2 for Mac OS X, take a look at the makerelease-osx.mk GNU Make makefile.

The quickest way to build aria2 is first to 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 a Windows binary. See Cross-compiling Android binary_ to create an Android binary.

The configure script checks available libraries and enables as many features as possible except for experimental features not 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 supplying 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 distri