<p>Declared in "<aclass="reference external"href="../include/libtorrent/add_torrent_params.hpp">libtorrent/add_torrent_params.hpp</a>"</p>
<p>The <aclass="reference external"href="reference-Session.html#add_torrent_params">add_torrent_params</a> is a parameter pack for adding torrents to a <aclass="reference external"href="reference-Session.html#session">session</a>.
The key fields when adding a torrent are:</p>
<ulclass="simple">
<li>ti - when you have a .torrent file</li>
<li>url - when you have a magnet link or http URL to the .torrent file</li>
<li>info_hash - when all you have is an info-hash (this is similar to a magnet link)</li>
</ul>
<p>one of those fields need to be set. Another mandatory field is <ttclass="docutils literal">save_path</tt>.
The <aclass="reference external"href="reference-Session.html#add_torrent_params">add_torrent_params</a> object is passed into one of the <ttclass="docutils literal"><spanclass="pre">session::add_torrent()</span></tt>
overloads or <ttclass="docutils literal"><spanclass="pre">session::async_add_torrent()</span></tt>.</p>
<p>If you only specify the info-hash, the torrent file will be downloaded from peers,
which requires them to support the metadata extension. For the metadata extension
to work, libtorrent must be built with extensions enabled (<ttclass="docutils literal">TORRENT_DISABLE_EXTENSIONS</tt> must not be
defined). It also takes an optional <ttclass="docutils literal">name</tt> argument. This may be left empty in case no
name should be assigned to the torrent. In case it's not, the name is used for
the torrent as long as it doesn't have metadata. See <ttclass="docutils literal"><spanclass="pre">torrent_handle::name</span></tt>.</p>
<p>The constructor can be used to initialize the storage constructor, which determines
the storage mechanism for the downloaded or seeding data for the torrent. For more
information, see the <ttclass="docutils literal">storage</tt> field.</p>
<aname="flags_t"></a></div>
<divclass="section"id="enum-flags-t">
<h2>enum flags_t</h2>
<p>Declared in "<aclass="reference external"href="../include/libtorrent/add_torrent_params.hpp">libtorrent/add_torrent_params.hpp</a>"</p>
<tableborder="1"class="docutils">
<colgroup>
<colwidth="21%"/>
<colwidth="5%"/>
<colwidth="74%"/>
</colgroup>
<theadvalign="bottom">
<tr><thclass="head">name</th>
<thclass="head">value</th>
<thclass="head">description</th>
</tr>
</thead>
<tbodyvalign="top">
<tr><td>flag_seed_mode</td>
<td>1</td>
<td><pclass="first">If <ttclass="docutils literal">flag_seed_mode</tt> is set, libtorrent will assume that all files are present
for this torrent and that they all match the hashes in the torrent file. Each time
a peer requests to download a block, the piece is verified against the hash, unless
it has been verified already. If a hash fails, the torrent will automatically leave
the seed mode and recheck all the files. The use case for this mode is if a torrent
is created and seeded, or if the user already know that the files are complete, this
is a way to avoid the initial file checks, and significantly reduce the startup time.</p>
<p>Setting <ttclass="docutils literal">flag_seed_mode</tt> on a torrent without metadata (a .torrent file) is a no-op
and will be ignored.</p>
<pclass="last">If resume data is passed in with this torrent, the seed mode saved in there will
override the seed mode you set here.</p>
</td>
</tr>
<tr><td>flag_override_resume_data</td>
<td>2</td>
<td><pclass="first">If <ttclass="docutils literal">flag_override_resume_data</tt> is set, the <ttclass="docutils literal">paused</tt> and <ttclass="docutils literal">auto_managed</tt>
state of the torrent are not loaded from the resume data, but the states requested
by the flags in <ttclass="docutils literal">add_torrent_params</tt> will override them.</p>
<pclass="last">If you pass in resume data, the paused state of the torrent when the resume data
was saved will override the paused state you pass in here. You can override this
by setting <ttclass="docutils literal">flag_override_resume_data</tt>.</p>
</td>
</tr>
<tr><td>flag_upload_mode</td>
<td>4</td>
<td><pclass="first">If <ttclass="docutils literal">flag_upload_mode</tt> is set, the torrent will be initialized in upload-mode,
which means it will not make any piece requests. This state is typically entered
on disk I/O errors, and if the torrent is also auto managed, it will be taken out
of this state periodically. This mode can be used to avoid race conditions when
adjusting priorities of pieces before allowing the torrent to start downloading.</p>
<pclass="last">If the torrent is auto-managed (<ttclass="docutils literal">flag_auto_managed</tt>), the torrent will eventually
be taken out of upload-mode, regardless of how it got there. If it's important to
manually control when the torrent leaves upload mode, don't make it auto managed.</p>
</td>
</tr>
<tr><td>flag_share_mode</td>
<td>8</td>
<td><pclass="first">determines if the torrent should be added in <em>share mode</em> or not.
Share mode indicates that we are not interested in downloading the torrent, but
merley want to improve our share ratio (i.e. increase it). A torrent started in
share mode will do its best to never download more than it uploads to the swarm.
If the swarm does not have enough demand for upload capacity, the torrent will
not download anything. This mode is intended to be safe to add any number of torrents
to, without manual screening, without the risk of downloading more than is uploaded.</p>
<p>A torrent in share mode sets the priority to all pieces to 0, except for the pieces
that are downloaded, when pieces are decided to be downloaded. This affects the progress
bar, which might be set to "100% finished" most of the time. Do not change file or piece
priorities for torrents in share mode, it will make it not work.</p>
<pclass="last">The share mode has one setting, the share ratio target, see <ttclass="docutils literal"><spanclass="pre">session_settings::share_mode_target</span></tt>
for more info.</p>
</td>
</tr>
<tr><td>flag_apply_ip_filter</td>
<td>16</td>
<td>determines if the IP filter should apply to this torrent or not. By
default all torrents are subject to filtering by the IP filter (i.e. this flag is set by
default). This is useful if certain torrents needs to be excempt for some reason, being
an auto-update torrent for instance.</td>
</tr>
<tr><td>flag_paused</td>
<td>32</td>
<td>specifies whether or not the torrent is to be started in a paused
state. I.e. it won't connect to the tracker or any of the peers until it's
resumed. This is typically a good way of avoiding race conditions when setting
configuration options on torrents before starting them.</td>
</tr>
<tr><td>flag_auto_managed</td>
<td>64</td>
<td><pclass="first">If the torrent is auto-managed (<ttclass="docutils literal">flag_auto_managed</tt>), the torrent may be resumed
at any point, regardless of how it paused. If it's important to manually control
when the torrent is paused and resumed, don't make it auto managed.</p>
<p>If <ttclass="docutils literal">flag_auto_managed</tt> is set, the torrent will be queued, started and seeded
automatically by libtorrent. When this is set, the torrent should also be started
as paused. The default queue order is the order the torrents were added. They
are all downloaded in that order. For more details, see <aclass="reference external"href="manual-ref.html#queuing">queuing</a>.</p>
<pclass="last">If you pass in resume data, the auto_managed state of the torrent when the resume data
was saved will override the auto_managed state you pass in here. You can override this
by setting <ttclass="docutils literal">override_resume_data</tt>.</p>
</td>
</tr>
<tr><td>flag_duplicate_is_error</td>
<td>128</td>
<td> </td>
</tr>
<tr><td>flag_merge_resume_trackers</td>
<td>256</td>
<td>defaults to off and specifies whether tracker URLs loaded from
resume data should be added to the trackers in the torrent or replace the trackers.</td>
</tr>
<tr><td>flag_update_subscribe</td>
<td>512</td>
<td>on by default and means that this torrent will be part of state
updates when calling <aclass="reference external"href="reference-Session.html#post_torrent_updates()">post_torrent_updates()</a>.</td>
</tr>
<tr><td>flag_super_seeding</td>
<td>1024</td>
<td>sets the torrent into super seeding mode. If the torrent
is not a seed, this flag has no effect. It has the same effect as calling
<ttclass="docutils literal"><spanclass="pre">torrent_handle::super_seeding(true)</span></tt> on the torrent handle immediately
after adding it.</td>
</tr>
<tr><td>flag_sequential_download</td>
<td>2048</td>
<td>sets the sequential download state for the torrent.
It has the same effect as calling <ttclass="docutils literal"><spanclass="pre">torrent_handle::sequential_download(true)</span></tt>
on the torrent handle immediately after adding it.</td>
</tr>
</tbody>
</table>
<aname="version"></a><dlclass="docutils">
<dt>version</dt>
<dd>filled in by the constructor and should be left untouched. It
is used for forward binary compatibility.</dd>
</dl>
<aname="ti"></a><dlclass="docutils">
<dt>ti</dt>
<dd><aclass="reference external"href="reference-Core.html#torrent_info">torrent_info</a> object with the torrent to add. Unless the url or info_hash
is set, this is required to be initiazlied.</dd>
</dl>
<aname="trackers"></a><dlclass="docutils">
<dt>trackers</dt>
<dd>If the torrent doesn't have a tracker, but relies on the DHT to find peers, the
<ttclass="docutils literal">trackers</tt> can specify tracker URLs for the torrent.</dd>
</dl>
<aname="dht_nodes"></a>
<aname="name"></a>
<aname="save_path"></a><dlclass="docutils">
<dt>dht_nodes name save_path</dt>
<dd>a list of hostname and port pairs, representing DHT nodes to be
added to the <aclass="reference external"href="reference-Session.html#session">session</a> (if DHT is enabled). The hostname may be an IP address.</dd>
</dl>
<aname="resume_data"></a><dlclass="docutils">
<dt>resume_data</dt>
<dd>The optional parameter, <ttclass="docutils literal">resume_data</tt> can be given if up to date fast-resume data
is available. The fast-resume data can be acquired from a running torrent by calling
<aclass="reference external"href="reference-Core.html#save_resume_data()">save_resume_data()</a> on <aclass="reference external"href="reference-Core.html#torrent_handle">torrent_handle</a>. See <aclass="reference external"href="manual-ref.html#fast-resume">fast resume</a>. The <ttclass="docutils literal">vector</tt> that is
passed in will be swapped into the running torrent instance with <ttclass="docutils literal"><spanclass="pre">std::vector::swap()</span></tt>.</dd>
</dl>
<aname="storage_mode"></a><dlclass="docutils">
<dt>storage_mode</dt>
<dd>One of the values from <aclass="reference external"href="reference-Storage.html#storage_mode_t">storage_mode_t</a>. For more information, see <aclass="reference external"href="manual-ref.html#storage-allocation">storage allocation</a>.</dd>
</dl>
<aname="storage"></a><dlclass="docutils">
<dt>storage</dt>
<dd>can be used to customize how the data is stored. The default
storage will simply write the data to the files it belongs to, but it could be
overridden to save everything to a single file at a specific location or encrypt the
content on disk for instance. For more information about the <aclass="reference external"href="reference-Custom_Storage.html#storage_interface">storage_interface</a>
that needs to be implemented for a custom storage, see <aclass="reference external"href="reference-Custom_Storage.html#storage_interface">storage_interface</a>.</dd>
</dl>
<aname="userdata"></a><dlclass="docutils">
<dt>userdata</dt>
<dd>The <ttclass="docutils literal">userdata</tt> parameter is optional and will be passed on to the extension
constructor functions, if any (see <aclass="reference internal"href="#add-extension">add_extension()</a>).</dd>
</dl>
<aname="file_priorities"></a><dlclass="docutils">
<dt>file_priorities</dt>
<dd>can be set to control the initial file priorities when adding
a torrent. The semantics are the same as for <ttclass="docutils literal"><spanclass="pre">torrent_handle::prioritize_files()</span></tt>.</dd>
</dl>
<aname="trackerid"></a><dlclass="docutils">
<dt>trackerid</dt>
<dd>the default tracker id to be used when announcing to trackers. By default
this is empty, and no tracker ID is used, since this is an optional argument. If
a tracker returns a tracker ID, that ID is used instead of this.</dd>
</dl>
<aname="url"></a><dlclass="docutils">
<dt>url</dt>
<dd><pclass="first">If you specify a <ttclass="docutils literal">url</tt>, the torrent will be set in <ttclass="docutils literal">downloading_metadata</tt> state
until the .torrent file has been downloaded. If there's any error while downloading,
the torrent will be stopped and the torrent error state (<ttclass="docutils literal"><spanclass="pre">torrent_status::error</span></tt>)
will indicate what went wrong. The <ttclass="docutils literal">url</tt> may refer to a magnet link or a regular
http URL.</p>
<p>If it refers to an HTTP URL, the info-hash for the added torrent will not be the
true info-hash of the .torrent. Instead a placeholder, unique, info-hash is used
which is later updated once the .torrent file has been downloaded.</p>
<pclass="last">Once the info-hash change happens, a <aclass="reference external"href="reference-Alerts.html#torrent_update_alert">torrent_update_alert</a> is posted.</p>
</dd>
</dl>
<aname="uuid"></a><dlclass="docutils">
<dt>uuid</dt>
<dd>if <ttclass="docutils literal">uuid</tt> is specified, it is used to find duplicates. If another torrent is already
running with the same UUID as the one being added, it will be considered a duplicate. This
is mainly useful for RSS feed items which has UUIDs specified.</dd>
</dl>
<aname="source_feed_url"></a><dlclass="docutils">
<dt>source_feed_url</dt>
<dd>should point to the URL of the RSS feed this torrent comes from,
if it comes from an RSS feed.</dd>
</dl>
<aname="flags"></a><dlclass="docutils">
<dt>flags</dt>
<dd>flags controlling aspects of this torrent and how it's added. See <aclass="reference external"href="reference-Core.html#flags_t">flags_t</a> for details.</dd>
</dl>
<aname="info_hash"></a><dlclass="docutils">
<dt>info_hash</dt>
<dd>set this to the info hash of the torrent to add in case the info-hash
is the only known property of the torrent. i.e. you don't have a
to the <ttclass="docutils literal">set_max_uploads()</tt>, <ttclass="docutils literal">set_max_connections()</tt>, <ttclass="docutils literal">set_upload_limit()</tt> and
<ttclass="docutils literal">set_download_limit()</tt> functions on <aclass="reference external"href="reference-Core.html#torrent_handle">torrent_handle</a>. These values let you initialize
these settings when the torrent is added, instead of calling these functions immediately
following adding it.</p>
<pclass="last">-1 means unlimited on these settings
just like their counterpart functions
on <aclass="reference external"href="reference-Core.html#torrent_handle">torrent_handle</a></p>
</dd>
</dl>
<aname="cache_status"></a></div>
</div>
<divclass="section"id="cache-status">
<h1>cache_status</h1>
<p>Declared in "<aclass="reference external"href="../include/libtorrent/disk_io_thread.hpp">libtorrent/disk_io_thread.hpp</a>"</p>
<p>this struct holds a number of statistics counters
relevant for the disk io thread and disk cache.</p>
<p>default constructor, does not refer to any <aclass="reference external"href="reference-Session.html#session">session</a>
implementation object.</p>
<aname="session"></a></div>
</div>
<divclass="section"id="id36">
<h1>session</h1>
<p>Declared in "<aclass="reference external"href="../include/libtorrent/session.hpp">libtorrent/session.hpp</a>"</p>
<p>The <aclass="reference external"href="reference-Session.html#session">session</a> holds all state that spans multiple torrents. Among other things it runs the network
loop and manages all torrents.
Once it's created, the <aclass="reference external"href="reference-Session.html#session">session</a> object will spawn the main thread that will do all the work.
The main thread will be idle as long it doesn't have any torrents to participate in.</p>
, int flags = start_default_features | add_default_plugins
, int alert_mask = alert::error_notification
TORRENT_LOGPATH_ARG_DEFAULT);
</pre>
<p>If the fingerprint in the first overload is omited, the client will get a default
fingerprint stating the version of libtorrent. The fingerprint is a short string that will be
used in the peer-id to identify the client and the client's version. For more details see the
fingerprint class. The constructor that only takes a fingerprint will not open a
listen port for the <aclass="reference external"href="reference-Session.html#session">session</a>, to get it running you'll have to call <ttclass="docutils literal"><spanclass="pre">session::listen_on()</span></tt>.
The other constructor, that takes a port range and an interface as well as the fingerprint
will automatically try to listen on a port on the given interface. For more information about
the parameters, see <ttclass="docutils literal">listen_on()</tt> function.</p>
<p>The flags paramater can be used to start default features (upnp & nat-pmp) and default plugins
(ut_metadata, ut_pex and smart_ban). The default is to start those things. If you do not want
them to start, pass 0 as the flags parameter.</p>
<p>The <ttclass="docutils literal">alert_mask</tt> is the same mask that you would send to <aclass="reference external"href="reference-Session.html#set_alert_mask()">set_alert_mask()</a>.</p>
<aname="~session()"></a></div>
<divclass="section"id="id43">
<h2>~session()</h2>
<preclass="literal-block">
<strong>~session</strong> ();
</pre>
<p>The destructor of <aclass="reference external"href="reference-Session.html#session">session</a> will notify all trackers that our torrents have been shut down.
If some trackers are down, they will time out. All this before the destructor of <aclass="reference external"href="reference-Session.html#session">session</a>
returns. So, it's advised that any kind of interface (such as windows) are closed before
destructing the <aclass="reference external"href="reference-Session.html#session">session</a> object. Because it can take a few second for it to finish. The
timeout can be set with <ttclass="docutils literal">set_settings()</tt>.</p>
void <strong>save_state</strong> (entry& e, boost::uint32_t flags = 0xffffffff) const;
</pre>
<p>loads and saves all <aclass="reference external"href="reference-Session.html#session">session</a> settings, including dht_settings, encryption settings and proxy
settings. <ttclass="docutils literal">save_state</tt> writes all keys to the <ttclass="docutils literal">entry</tt> that's passed in, which needs to
either not be initialized, or initialized as a dictionary.</p>
<p><ttclass="docutils literal">load_state</tt> expects a <aclass="reference external"href="reference-Bencoding.html#lazy_entry">lazy_entry</a> which can be built from a bencoded buffer with
lazy_bdecode().</p>
<p>The <ttclass="docutils literal">flags</tt> arguments passed in to <ttclass="docutils literal">save_state</tt> can be used to filter which parts
of the <aclass="reference external"href="reference-Session.html#session">session</a> state to save. By default, all state is saved (except for the individual
torrents). see <aclass="reference external"href="reference-Session.html#save_state_flags_t">save_state_flags_t</a></p>
void <strong>refresh_torrent_status</strong> (std::vector<torrent_status>* ret
, boost::uint32_t flags = 0) const;
void <strong>get_torrent_status</strong> (std::vector<torrent_status>* ret
, boost::function<bool(torrent_status const&)> const& pred
, boost::uint32_t flags = 0) const;
</pre>
<divclass="note">
<pclass="first admonition-title">Note</p>
<pclass="last">these calls are potentially expensive and won't scale well
with lots of torrents. If you're concerned about performance, consider
using <ttclass="docutils literal">post_torrent_updates()</tt> instead.</p>
</div>
<p><ttclass="docutils literal">get_torrent_status</tt> returns a vector of the <aclass="reference external"href="reference-Core.html#torrent_status">torrent_status</a> for every
torrent which satisfies <ttclass="docutils literal">pred</tt>, which is a predicate function which determines
if a torrent should be included in the returned set or not. Returning true means
it should be included and false means excluded. The <ttclass="docutils literal">flags</tt> argument is the same
as to <ttclass="docutils literal"><spanclass="pre">torrent_handle::status()</span></tt>. Since <ttclass="docutils literal">pred</tt> is guaranteed to be called for
every torrent, it may be used to count the number of torrents of different categories
as well.</p>
<p><ttclass="docutils literal">refresh_torrent_status</tt> takes a vector of <aclass="reference external"href="reference-Core.html#torrent_status">torrent_status</a> structs (for instance
the same vector that was returned by <aclass="reference external"href="reference-Session.html#get_torrent_status()">get_torrent_status()</a> ) and refreshes the
status based on the <ttclass="docutils literal">handle</tt> member. It is possible to use this function by
first setting up a vector of default constructed <ttclass="docutils literal">torrent_status</tt> objects, only
initializing the <ttclass="docutils literal">handle</tt> member, in order to request the torrent status for
multiple torrents in a single call. This can save a significant amount of time
if you have a lot of torrents.</p>
<p>Any <aclass="reference external"href="reference-Core.html#torrent_status">torrent_status</a> object whose <ttclass="docutils literal">handle</tt> member is not referring to a
valid torrent are ignored.</p>
<aname="post_torrent_updates()"></a></div>
<divclass="section"id="post-torrent-updates">
<h2>post_torrent_updates()</h2>
<preclass="literal-block">
void <strong>post_torrent_updates</strong> ();
</pre>
<p>This functions instructs the <aclass="reference external"href="reference-Session.html#session">session</a> to post the <aclass="reference external"href="reference-Alerts.html#state_update_alert">state_update_alert</a>, containing
the status of all torrents whose state changed since the last time this function
was called.</p>
<p>Only torrents who has the state subscription flag set will be included. This flag
is on by default. See <aclass="reference external"href="reference-Session.html#add_torrent_params">add_torrent_params</a>.</p>
<p><ttclass="docutils literal">find_torrent()</tt> looks for a torrent with the given info-hash. In case there
is such a torrent in the <aclass="reference external"href="reference-Session.html#session">session</a>, a <aclass="reference external"href="reference-Core.html#torrent_handle">torrent_handle</a> to that torrent is returned.
In case the torrent cannot be found, an invalid <aclass="reference external"href="reference-Core.html#torrent_handle">torrent_handle</a> is returned.</p>
<p>See <ttclass="docutils literal"><spanclass="pre">torrent_handle::is_valid()</span></tt> to know if the torrent was found or not.</p>
<p><ttclass="docutils literal">get_torrents()</tt> returns a vector of torrent_handles to all the torrents
currently in the <aclass="reference external"href="reference-Session.html#session">session</a>.</p>
<p>You add torrents through the <aclass="reference external"href="reference-Session.html#add_torrent()">add_torrent()</a> function where you give an
object with all the parameters. The <aclass="reference external"href="reference-Session.html#add_torrent()">add_torrent()</a> overloads will block
until the torrent has been added (or failed to be added) and returns an
error code and a <aclass="reference external"href="reference-Core.html#torrent_handle">torrent_handle</a>. In order to add torrents more efficiently,
consider using <aclass="reference external"href="reference-Session.html#async_add_torrent()">async_add_torrent()</a> which returns immediately, without
waiting for the torrent to add. Notification of the torrent being added is sent
as <aclass="reference external"href="reference-Alerts.html#add_torrent_alert">add_torrent_alert</a>.</p>
<p>The overload that does not take an error_code throws an exception on
error and is not available when building without exception support.
The <aclass="reference external"href="reference-Core.html#torrent_handle">torrent_handle</a> returned by <aclass="reference external"href="reference-Session.html#add_torrent()">add_torrent()</a> can be used to retrieve information
about the torrent's progress, its peers etc. It is also used to abort a torrent.</p>
<p>If the torrent you are trying to add already exists in the <aclass="reference external"href="reference-Session.html#session">session</a> (is either queued
for checking, being checked or downloading) <ttclass="docutils literal">add_torrent()</tt> will throw
<aclass="reference external"href="reference-Error_Codes.html#libtorrent_exception">libtorrent_exception</a> which derives from <ttclass="docutils literal"><spanclass="pre">std::exception</span></tt> unless duplicate_is_error
is set to false. In that case, <aclass="reference external"href="reference-Session.html#add_torrent()">add_torrent()</a> will return the handle to the existing
torrent.</p>
<p>all torrent_handles must be destructed before the <aclass="reference external"href="reference-Session.html#session">session</a> is destructed!</p>
<aname="abort()"></a></div>
<divclass="section"id="abort">
<h2>abort()</h2>
<preclass="literal-block">
session_proxy <strong>abort</strong> ();
</pre>
<p>In case you want to destruct the <aclass="reference external"href="reference-Session.html#session">session</a> asynchrounously, you can request a <aclass="reference external"href="reference-Session.html#session">session</a>
destruction proxy. If you don't do this, the destructor of the <aclass="reference external"href="reference-Session.html#session">session</a> object will
block while the trackers are contacted. If you keep one <ttclass="docutils literal">session_proxy</tt> to the
<aclass="reference external"href="reference-Session.html#session">session</a> when destructing it, the destructor will not block, but start to close down
the <aclass="reference external"href="reference-Session.html#session">session</a>, the destructor of the proxy will then synchronize the threads. So, the
destruction of the <aclass="reference external"href="reference-Session.html#session">session</a> is performed from the <ttclass="docutils literal">session</tt> destructor call until the
<ttclass="docutils literal">session_proxy</tt> destructor call. The <ttclass="docutils literal">session_proxy</tt> does not have any operations
on it (since the <aclass="reference external"href="reference-Session.html#session">session</a> is being closed down, no operations are allowed on it). The
only valid operation is calling the destructor:</p>
<preclass="literal-block">
class session_proxy
{
public:
session_proxy();
~session_proxy()
};
</pre>
<aname="pause()"></a>
<aname="resume()"></a>
<aname="is_paused()"></a></div>
<divclass="section"id="pause-resume-is-paused">
<h2>pause() resume() is_paused()</h2>
<preclass="literal-block">
void <strong>resume</strong> ();
void <strong>pause</strong> ();
bool <strong>is_paused</strong> () const;
</pre>
<p>Pausing the <aclass="reference external"href="reference-Session.html#session">session</a> has the same effect as pausing every torrent in it, except that
torrents will not be resumed by the auto-manage mechanism. Resuming will restore the
torrents to their previous paused state. i.e. the <aclass="reference external"href="reference-Session.html#session">session</a> pause state is separate from
the torrent pause state. A torrent is inactive if it is paused or if the <aclass="reference external"href="reference-Session.html#session">session</a> is
paused.</p>
<aname="status()"></a></div>
<divclass="section"id="status">
<h2>status()</h2>
<preclass="literal-block">
session_status <strong>status</strong> () const;
</pre>
<p>returns <aclass="reference external"href="reference-Session.html#session">session</a> wide-statistics and status. For more information, see the <ttclass="docutils literal">session_status</tt> struct.</p>
These functions are not available in case <ttclass="docutils literal">TORRENT_DISABLE_DHT</tt> is
defined. <ttclass="docutils literal">start_dht</tt> starts the dht node and makes the trackerless service
available to torrents. The startup state is optional and can contain nodes
and the node id from the previous <aclass="reference external"href="reference-Session.html#session">session</a>. The dht node state is a bencoded
dictionary with the following entries:</p>
<dlclass="docutils">
<dt>nodes</dt>
<dd>A list of strings, where each string is a node endpoint encoded in binary. If
the string is 6 bytes long, it is an IPv4 address of 4 bytes, encoded in
network byte order (big endian), followed by a 2 byte port number (also
network byte order). If the string is 18 bytes long, it is 16 bytes of IPv6
address followed by a 2 bytes port number (also network byte order).</dd>
<dt>node-id</dt>
<dd>The node id written as a readable string as a hexadecimal number.</dd>
</dl>
<p><ttclass="docutils literal">dht_state</tt> will return the current state of the dht node, this can be used
to start up the node again, passing this <aclass="reference external"href="reference-Bencoding.html#entry">entry</a> to <ttclass="docutils literal">start_dht</tt>. It is a good
idea to save this to disk when the <aclass="reference external"href="reference-Session.html#session">session</a> is closed, and read it up again
when starting.</p>
<p>If the port the DHT is supposed to listen on is already in use, and exception
is thrown, <ttclass="docutils literal"><spanclass="pre">asio::error</span></tt>.</p>
<p><ttclass="docutils literal">stop_dht</tt> stops the dht node.</p>
<p><ttclass="docutils literal">add_dht_node</tt> adds a node to the routing table. This can be used if your
client has its own source of bootstrapping nodes.</p>
<p><ttclass="docutils literal">set_dht_settings</tt> sets some parameters availavle to the dht node. See
dht_settings for more information.</p>
<p><ttclass="docutils literal">is_dht_running()</tt> returns true if the DHT support has been started and false
int <strong>as_for_ip</strong> (address const& addr);
</pre>
<p>These functions are not available if <ttclass="docutils literal">TORRENT_DISABLE_GEO_IP</tt> is defined. They
expects a path to the <aclass="reference external"href="http://www.maxmind.com/app/asnum">MaxMind ASN database</a> and <aclass="reference external"href="http://www.maxmind.com/app/geolitecountry">MaxMind GeoIP database</a>
respectively. This will be used to look up which AS and country peers belong to.</p>
<p><ttclass="docutils literal">as_for_ip</tt> returns the AS number for the IP address specified. If the IP is not
in the database or the ASN database is not loaded, 0 is returned.</p>
<p>Sets a filter that will be used to reject and accept incoming as well as outgoing
connections based on their originating ip address. The default filter will allow
connections to any ip address. To build a set of rules for which addresses are
accepted and not, see <aclass="reference external"href="reference-Filter.html#ip_filter">ip_filter</a>.</p>
<p>Each time a peer is blocked because of the IP filter, a <aclass="reference external"href="reference-Alerts.html#peer_blocked_alert">peer_blocked_alert</a> is
generated.
<ttclass="docutils literal">get_ip_filter()</tt> Returns the <aclass="reference external"href="reference-Filter.html#ip_filter">ip_filter</a> currently in the <aclass="reference external"href="reference-Session.html#session">session</a>. See <aclass="reference external"href="reference-Filter.html#ip_filter">ip_filter</a>.</p>
<p>apply <aclass="reference external"href="reference-Filter.html#port_filter">port_filter</a><ttclass="docutils literal">f</tt> to incoming and outgoing peers.
a port filter will reject making outgoing peer connections
to certain remote ports. The main intention is to be able
to avoid triggering certain anti-virus software by connecting
unsigned short <strong>listen_port</strong> () const;
unsigned short <strong>ssl_listen_port</strong> () const;
</pre>
<p><ttclass="docutils literal">is_listening()</tt> will tell you whether or not the <aclass="reference external"href="reference-Session.html#session">session</a> has successfully
opened a listening port. If it hasn't, this function will return false, and
then you can use <ttclass="docutils literal">listen_on()</tt> to make another attempt.</p>
<p><ttclass="docutils literal">listen_port()</tt> returns the port we ended up listening on. Since you just pass
a port-range to the constructor and to <ttclass="docutils literal">listen_on()</tt>, to know which port it
ended up using, you have to ask the <aclass="reference external"href="reference-Session.html#session">session</a> using this function.</p>
<p><ttclass="docutils literal">listen_on()</tt> will change the listen port and/or the listen interface. If the
<aclass="reference external"href="reference-Session.html#session">session</a> is already listening on a port, this socket will be closed and a new socket
will be opened with these new settings. The port range is the ports it will try
to listen on, if the first port fails, it will continue trying the next port within
the range and so on. The interface parameter can be left as 0, in that case the
os will decide which interface to listen on, otherwise it should be the ip-address
of the interface you want the listener socket bound to. <ttclass="docutils literal">listen_on()</tt> returns the
error code of the operation in <ttclass="docutils literal">ec</tt>. If this indicates success, the <aclass="reference external"href="reference-Session.html#session">session</a> is
listening on a port within the specified range. If it fails, it will also
generate an appropriate <aclass="reference external"href="reference-Alerts.html#alert">alert</a> (listen_failed_alert).</p>
<p>If all ports in the specified range fails to be opened for listening, libtorrent will
try to use port 0 (which tells the operating system to pick a port that's free). If
that still fails you may see a <aclass="reference external"href="reference-Alerts.html#listen_failed_alert">listen_failed_alert</a> with port 0 even if you didn't
ask to listen on it.</p>
<p>It is possible to prevent libtorrent from binding to port 0 by passing in the flag
<ttclass="docutils literal"><spanclass="pre">session::no_system_port</span></tt> in the <ttclass="docutils literal">flags</tt> argument.</p>
<p>The interface parameter can also be a hostname that will resolve to the device you
want to listen on. If you don't specify an interface, libtorrent may attempt to
listen on multiple interfaces (typically 0.0.0.0 and ::). This means that if your
IPv6 interface doesn't work, you may still see a <aclass="reference external"href="reference-Alerts.html#listen_failed_alert">listen_failed_alert</a>, even though
the IPv4 port succeeded.</p>
<p>The <ttclass="docutils literal">flags</tt> parameter can either be 0 or <ttclass="docutils literal"><spanclass="pre">session::listen_reuse_address</span></tt>, which
will set the reuse address socket option on the listen socket(s). By default, the
listen socket does not use reuse address. If you're running a service that needs
to run on a specific port no matter if it's in use, set this flag.</p>
<p>If you're also starting the DHT, it is a good idea to do that after you've called
<ttclass="docutils literal">listen_on()</tt>, since the default listen port for the DHT is the same as the tcp
listen socket. If you start the DHT first, it will assume the tcp port is free and
open the udp socket on that port, then later, when <ttclass="docutils literal">listen_on()</tt> is called, it
may turn out that the tcp port is in use. That results in the DHT and the bittorrent
socket listening on different ports. If the DHT is active when <ttclass="docutils literal">listen_on</tt> is
called, the udp port will be rebound to the new port, if it was configured to use
the same port as the tcp socket, and if the listen_on call failed to bind to the
same port that the udp uses.</p>
<p>If you want the OS to pick a port for you, pass in 0 as both first and second.</p>
<p>The reason why it's a good idea to run the DHT and the bittorrent socket on the same
port is because that is an assumption that may be used to increase performance. One
way to accelerate the connecting of peers on windows may be to first ping all peers
with a DHT ping packet, and connect to those that responds first. On windows one
can only connect to a few peers at a time because of a built in limitation (in XP
Service pack 2).</p>
<aname="remove_torrent()"></a></div>
<divclass="section"id="remove-torrent">
<h2>remove_torrent()</h2>
<preclass="literal-block">
void <strong>remove_torrent</strong> (const torrent_handle& h, int options = 0);
</pre>
<p><ttclass="docutils literal">remove_torrent()</tt> will close all peer connections associated with the torrent and tell
the tracker that we've stopped participating in the swarm. This operation cannot fail.
When it completes, you will receive a <aclass="reference external"href="reference-Alerts.html#torrent_removed_alert">torrent_removed_alert</a>.</p>
<p>The optional second argument <ttclass="docutils literal">options</tt> can be used to delete all the files downloaded
by this torrent. To do so, pass in the value <ttclass="docutils literal"><spanclass="pre">session::delete_files</span></tt>. The removal
of the torrent is asyncronous, there is no guarantee that adding the same torrent
immediately after it was removed will not throw a <aclass="reference external"href="reference-Error_Codes.html#libtorrent_exception">libtorrent_exception</a> exception. Once
the torrent is deleted, a <aclass="reference external"href="reference-Alerts.html#torrent_deleted_alert">torrent_deleted_alert</a> is posted.</p>
<p>These functions sets and queries the proxy settings to be used for the <aclass="reference external"href="reference-Session.html#session">session</a>.</p>
<p>For more information on what settings are available for proxies, see
<aclass="reference external"href="reference-Settings.html#proxy_settings">proxy_settings</a>. If the <aclass="reference external"href="reference-Session.html#session">session</a> is not in anonymous mode, proxies that
aren't working or fail, will automatically be disabled and packets will
flow without using any proxy. If you want to enforce using a proxy, even when
the proxy doesn't work, enable anonymous_mode in <aclass="reference external"href="reference-Settings.html#session_settings">session_settings</a>.</p>
<p><ttclass="docutils literal">set_i2p_proxy</tt> sets the <aclass="reference external"href="http://www.i2p2.de">i2p</a> proxy, and tries to open a persistant
connection to it. The only used fields in the proxy settings structs
are <ttclass="docutils literal">hostname</tt> and <ttclass="docutils literal">port</tt>.</p>
<p><ttclass="docutils literal">i2p_proxy</tt> returns the current i2p proxy in use.</p>
<p><ttclass="docutils literal">pop_alert()</tt> is used to ask the <aclass="reference external"href="reference-Session.html#session">session</a> if any errors or events has occurred. With
<aclass="reference external"href="reference-Session.html#set_alert_mask()">set_alert_mask()</a> you can filter which alerts to receive through <ttclass="docutils literal">pop_alert()</tt>.
For information about the <aclass="reference external"href="reference-Alerts.html#alert">alert</a> categories, see <aclass="reference external"href="manual-ref.html#alerts">alerts</a>.</p>
<p><ttclass="docutils literal">pop_alerts()</tt> pops all pending alerts in a single call. In high performance environments
with a very high <aclass="reference external"href="reference-Alerts.html#alert">alert</a> churn rate, this can save significant amount of time compared to
popping alerts one at a time. Each call requires one round-trip to the network thread. If
alerts are produced in a higher rate than they can be popped (when popped one at a time)
it's easy to get stuck in an infinite loop, trying to drain the <aclass="reference external"href="reference-Alerts.html#alert">alert</a> queue. Popping the entire
queue at once avoids this problem.</p>
<p>However, the <ttclass="docutils literal">pop_alerts</tt> function comes with significantly more responsibility. You pass
in an <em>empty</em><ttclass="docutils literal"><spanclass="pre">std::dequeue<alert*></span></tt> to it. If it's not empty, all elements in it will
be deleted and then cleared. All currently pending alerts are returned by being swapped
into the passed in container. The responsibility of deleting the alerts is transferred
to the caller. This means you need to call delete for each item in the returned dequeue.
It's probably a good idea to delete the alerts as you handle them, to save one extra
pass over the dequeue.</p>
<p>Alternatively, you can pass in the same container the next time you call <ttclass="docutils literal">pop_alerts</tt>.</p>
<p><ttclass="docutils literal">wait_for_alert</tt> blocks until an <aclass="reference external"href="reference-Alerts.html#alert">alert</a> is available, or for no more than <ttclass="docutils literal">max_wait</tt>
time. If <ttclass="docutils literal">wait_for_alert</tt> returns because of the time-out, and no alerts are available,
it returns 0. If at least one <aclass="reference external"href="reference-Alerts.html#alert">alert</a> was generated, a pointer to that <aclass="reference external"href="reference-Alerts.html#alert">alert</a> is returned.
The <aclass="reference external"href="reference-Alerts.html#alert">alert</a> is not popped, any subsequent calls to <ttclass="docutils literal">wait_for_alert</tt> will return the
same pointer until the <aclass="reference external"href="reference-Alerts.html#alert">alert</a> is popped by calling <ttclass="docutils literal">pop_alert</tt>. This is useful for
leaving any <aclass="reference external"href="reference-Alerts.html#alert">alert</a> dispatching mechanism independent of this blocking call, the dispatcher
can be called and it can pop the <aclass="reference external"href="reference-Alerts.html#alert">alert</a> independently.</p>
<p>In the python binding, <ttclass="docutils literal">wait_for_alert</tt> takes the number of milliseconds to wait as an integer.</p>
<p>To control the max number of alerts that's queued by the <aclass="reference external"href="reference-Session.html#session">session</a>, see
<p><aclass="reference external"href="reference-Alerts.html#save_resume_data_alert">save_resume_data_alert</a> and <aclass="reference external"href="reference-Alerts.html#save_resume_data_failed_alert">save_resume_data_failed_alert</a> are always posted, regardelss
of the <aclass="reference external"href="reference-Alerts.html#alert">alert</a> mask.</p>
<p>This sets a function to be called (from within libtorrent's netowrk thread) every time an <aclass="reference external"href="reference-Alerts.html#alert">alert</a>
is posted. Since the function (<ttclass="docutils literal">fun</tt>) is run in libtorrent's internal thread, it may not call
any of libtorrent's external API functions. Doing so results in a dead lock.</p>
<p>The main intention with this function is to support integration with platform-dependent message
queues or signalling systems. For instance, on windows, one could post a message to an HNWD or
on linux, write to a pipe or an eventfd.</p>
<aname="start_lsd()"></a>
<aname="stop_lsd()"></a></div>
<divclass="section"id="start-lsd-stop-lsd">
<h2>start_lsd() stop_lsd()</h2>
<preclass="literal-block">
void <strong>stop_lsd</strong> ();
void <strong>start_lsd</strong> ();
</pre>
<p>Starts and stops Local Service Discovery. This service will broadcast
the infohashes of all the non-private torrents on the local network to
look for peers on the same swarm within multicast reach.</p>
<p>It is turned off by default.</p>
<aname="stop_upnp()"></a>
<aname="start_upnp()"></a></div>
<divclass="section"id="stop-upnp-start-upnp">
<h2>stop_upnp() start_upnp()</h2>
<preclass="literal-block">
void <strong>stop_upnp</strong> ();
void <strong>start_upnp</strong> ();
</pre>
<p>Starts and stops the UPnP service. When started, the listen port and the DHT
port are attempted to be forwarded on local UPnP router devices.</p>
<p>The upnp object returned by <ttclass="docutils literal">start_upnp()</tt> can be used to add and remove
arbitrary port mappings. Mapping status is returned through the
<aclass="reference external"href="reference-Alerts.html#portmap_alert">portmap_alert</a> and the <aclass="reference external"href="reference-Alerts.html#portmap_error_alert">portmap_error_alert</a>. The object will be valid until
<ttclass="docutils literal">stop_upnp()</tt> is called. See <aclass="reference external"href="manual-ref.html#upnp-and-nat-pmp">upnp and nat pmp</a>.</p>
<p>It is off by default.</p>
<aname="start_natpmp()"></a>
<aname="stop_natpmp()"></a></div>
<divclass="section"id="start-natpmp-stop-natpmp">
<h2>start_natpmp() stop_natpmp()</h2>
<preclass="literal-block">
void <strong>stop_natpmp</strong> ();
void <strong>start_natpmp</strong> ();
</pre>
<p>Starts and stops the NAT-PMP service. When started, the listen port and the DHT
port are attempted to be forwarded on the router through NAT-PMP.</p>
<p>The natpmp object returned by <ttclass="docutils literal">start_natpmp()</tt> can be used to add and remove
arbitrary port mappings. Mapping status is returned through the
<aclass="reference external"href="reference-Alerts.html#portmap_alert">portmap_alert</a> and the <aclass="reference external"href="reference-Alerts.html#portmap_error_alert">portmap_error_alert</a>. The object will be valid until
<ttclass="docutils literal">stop_natpmp()</tt> is called. See <aclass="reference external"href="manual-ref.html#upnp-and-nat-pmp">upnp and nat pmp</a>.</p>
<p>It is off by default.</p>
<aname="save_state_flags_t"></a></div>
<divclass="section"id="enum-save-state-flags-t">
<h2>enum save_state_flags_t</h2>
<p>Declared in "<aclass="reference external"href="../include/libtorrent/session.hpp">libtorrent/session.hpp</a>"</p>
<tableborder="1"class="docutils">
<colgroup>
<colwidth="57%"/>
<colwidth="15%"/>
<colwidth="28%"/>
</colgroup>
<theadvalign="bottom">
<tr><thclass="head">name</th>
<thclass="head">value</th>
<thclass="head">description</th>
</tr>
</thead>
<tbodyvalign="top">
<tr><td>save_settings</td>
<td>1</td>
<td> </td>
</tr>
<tr><td>save_dht_settings</td>
<td>2</td>
<td> </td>
</tr>
<tr><td>save_dht_state</td>
<td>4</td>
<td> </td>
</tr>
<tr><td>save_proxy</td>
<td>8</td>
<td> </td>
</tr>
<tr><td>save_i2p_proxy</td>
<td>16</td>
<td> </td>
</tr>
<tr><td>save_encryption_settings</td>
<td>32</td>
<td> </td>
</tr>
<tr><td>save_as_map</td>
<td>64</td>
<td> </td>
</tr>
<tr><td>save_feeds</td>
<td>128</td>
<td> </td>
</tr>
</tbody>
</table>
<aname="listen_on_flags_t"></a></div>
<divclass="section"id="enum-listen-on-flags-t">
<h2>enum listen_on_flags_t</h2>
<p>Declared in "<aclass="reference external"href="../include/libtorrent/session.hpp">libtorrent/session.hpp</a>"</p>
<tableborder="1"class="docutils">
<colgroup>
<colwidth="53%"/>
<colwidth="16%"/>
<colwidth="30%"/>
</colgroup>
<theadvalign="bottom">
<tr><thclass="head">name</th>
<thclass="head">value</th>
<thclass="head">description</th>
</tr>
</thead>
<tbodyvalign="top">
<tr><td>listen_no_system_port</td>
<td>2</td>
<td> </td>
</tr>
</tbody>
</table>
<aname="options_t"></a></div>
<divclass="section"id="enum-options-t">
<h2>enum options_t</h2>
<p>Declared in "<aclass="reference external"href="../include/libtorrent/session.hpp">libtorrent/session.hpp</a>"</p>
<tableborder="1"class="docutils">
<colgroup>
<colwidth="41%"/>
<colwidth="21%"/>
<colwidth="38%"/>
</colgroup>
<theadvalign="bottom">
<tr><thclass="head">name</th>
<thclass="head">value</th>
<thclass="head">description</th>
</tr>
</thead>
<tbodyvalign="top">
<tr><td>delete_files</td>
<td>1</td>
<td> </td>
</tr>
</tbody>
</table>
<aname="session_flags_t"></a></div>
<divclass="section"id="enum-session-flags-t">
<h2>enum session_flags_t</h2>
<p>Declared in "<aclass="reference external"href="../include/libtorrent/session.hpp">libtorrent/session.hpp</a>"</p>
<tableborder="1"class="docutils">
<colgroup>
<colwidth="55%"/>
<colwidth="16%"/>
<colwidth="30%"/>
</colgroup>
<theadvalign="bottom">
<tr><thclass="head">name</th>
<thclass="head">value</th>
<thclass="head">description</th>
</tr>
</thead>
<tbodyvalign="top">
<tr><td>add_default_plugins</td>
<td>1</td>
<td> </td>
</tr>
<tr><td>start_default_features</td>
<td>2</td>
<td> </td>
</tr>
</tbody>
</table>
<aname="dht_lookup"></a></div>
</div>
<divclass="section"id="dht-lookup">
<h1>dht_lookup</h1>
<p>Declared in "<aclass="reference external"href="../include/libtorrent/session_status.hpp">libtorrent/session_status.hpp</a>"</p>
<p>holds statistics about a current <aclass="reference external"href="reference-Session.html#dht_lookup">dht_lookup</a> operation.
a DHT lookup is the travesal of nodes, looking up a
set of target nodes in the DHT for retrieving and possibly
storing information in the DHT</p>
<preclass="literal-block">
struct dht_lookup
{
char const* type;
int outstanding_requests;
int timeouts;
int responses;
int branch_factor;
int nodes_left;
int last_sent;
int first_timeout;
};
</pre>
<aname="type"></a><dlclass="docutils">
<dt>type</dt>
<dd>string literal indicating which kind of lookup this is</dd>
<dd>the number of bytes that has been received more than once.
This can happen if a request from a peer times out and is requested from a different
peer, and then received again from the first one. To make this lower, increase the
<ttclass="docutils literal">request_timeout</tt> and the <ttclass="docutils literal">piece_timeout</tt> in the <aclass="reference external"href="reference-Session.html#session">session</a> settings.</dd>
<p>The default values of the <aclass="reference external"href="reference-Session.html#session">session</a> settings are set for a regular bittorrent client running
on a desktop system. There are functions that can set the <aclass="reference external"href="reference-Session.html#session">session</a> settings to pre set
settings for other environments. These can be used for the basis, and should be tweaked to
fit your needs better.</p>
<p><ttclass="docutils literal">min_memory_usage</tt> returns settings that will use the minimal amount of RAM, at the
potential expense of upload and download performance. It adjusts the socket buffer sizes,
disables the disk cache, lowers the send buffer watermarks so that each connection only has
at most one block in use at any one time. It lowers the outstanding blocks send to the disk
I/O thread so that connections only have one block waiting to be flushed to disk at any given
time. It lowers the max number of peers in the peer list for torrents. It performs multiple
smaller reads when it hashes pieces, instead of reading it all into memory before hashing.</p>
<p>This configuration is inteded to be the starting point for embedded devices. It will
significantly reduce memory usage.</p>
<p><ttclass="docutils literal">high_performance_seed</tt> returns settings optimized for a seed box, serving many peers
and that doesn't do any downloading. It has a 128 MB disk cache and has a limit of 400 files
in its file pool. It support fast upload rates by allowing large send buffers.</p>
