Kontaktstyring

I dette afsnit præsenteres, hvordan du finder og tilføjer en kontakt fra DHT til klienten. Brug af en navneserver vil ikke blive forklaret her. Hvis du ønsker mere detaljer om det, kan du læse Navne Server protokol.

Tilstedeværelse på netværket

Annoncer tilstedeværelsen på DHT

Det er ganske enkelt at annoncere tilstedeværelsen på DHT. Faktisk er det bare en værdi, der indeholder en enhedshash (se det foregående afsnit, konto-styring) på hashet svarende til fingeraftrykket på nøglen. Så hvis vi har kontoen bf5f1e21d3eb2c1246946aa49d5dcf3e5b9cb1b9 med enheden 62fbdff0ce86f368c7d3c2682539e5ba9e06404f, vil følgende definerede værdi blive sendt over DHT:

/**
 * Device announcement stored on DHT.
 */
struct DeviceAnnouncement : public dht::SignedValue<DeviceAnnouncement>
{
private:
    using BaseClass = dht::SignedValue<DeviceAnnouncement>;

public:
    static const constexpr dht::ValueType& TYPE = dht::ValueType::USER_DATA;
    dht::InfoHash dev;
    std::shared_ptr<dht::crypto::PublicKey> pk;
    MSGPACK_DEFINE_MAP(dev, pk)
};

(Denne værdi kan indsættes med dht_.put(h, VALUE, dht::DoneCallback{}, {}, true);, som en permanent put). Hvis enheden annonceres, er enheden til stede. For nu er der ingen måde at slette eller redigere en værdi på DHT (dette vil komme, når OpenDHT understøtter ECC). Så tilstedeværelsen har altid en forsinkelse for nu (mean delay: expir-time/2, så 2min30 for nu).

Ring, hvis der er kontakt

Now our presence on the network, it’s time to get if somebody is present on the DHT. With the previous section, it’s easy to do the reverse process. To know if somebody is present on the DHT (ex: bf5f1e21d3eb2c1246946aa49d5dcf3e5b9cb1b9), we have to get value at bf5f1e21d3eb2c1246946aa49d5dcf3e5b9cb1b9 and retrieve the DeviceAnnouncement on this hash. The related code in the daemon is in jamiaccount.cpp:

auto shared = std::static_pointer_cast<RingAccount>(shared_from_this());
auto treatedDevices = std::make_shared<std::set<dht::InfoHash>>();
dht_.get<dht::crypto::RevocationList>(to, [to](dht::crypto::RevocationList&& crl){
    tls::CertificateStore::instance().pinRevocationList(to.toString(), std::move(crl));
    return true;
});
dht_.get<DeviceAnnouncement>(to, [shared,to,treatedDevices,op](DeviceAnnouncement&& dev) {
    if (dev.from != to)
        return true;
    if (treatedDevices->emplace(dev.dev).second)
        op(shared, dev.dev);
    return true;
}, [=](bool /*ok*/){
    {
        std::lock_guard<std::recursive_mutex> lock(shared->buddyInfoMtx);
        auto buddy_info_it = shared->trackedBuddies_.find(to);
        if (buddy_info_it != shared->trackedBuddies_.end()) {
            if (not treatedDevices->empty()) {
                for (auto& device_id : *treatedDevices)
                    shared->onTrackedBuddyOnline(buddy_info_it, device_id);
            } else
                shared->onTrackedBuddyOffline(buddy_info_it);
        }
    }
    RING_DBG("[Account %s] found %lu devices for %s",
                getAccountID().c_str(), treatedDevices->size(), to.to_c_str());
    if (end) end(shared, not treatedDevices->empty());
});

And that’s all.

Client perspective

<method name="subscribeBuddy" tp:name-for-bindings="subscribeBuddy">
    <tp:docstring>
        Ask be be notified when 'uri' presence change
    </tp:docstring>
    <tp:added version="1.3.0"/>
    <arg type="s" name="accountID" direction="in">
        <tp:docstring>
            An account from which get request presence informations
        </tp:docstring>
    </arg>
    <arg type="s" name="uri" direction="in">
        <tp:docstring>
            A SIP uri to watch
        </tp:docstring>
    </arg>
    <arg type="b" name="flag" direction="in">
        <tp:docstring>
        </tp:docstring>
    </arg>
</method>

<signal name="newBuddyNotification" tp:name-for-bindings="newBuddyNotification">
    <tp:added version="1.3.0"/>
    <tp:docstring>
        Notify when a registered presence uri presence informations changes
    </tp:docstring>
    <arg type="s" name="accountID">
        <tp:docstring>
            The associated account
        </tp:docstring>
    </arg>
    <arg type="s" name="buddyUri">
        <tp:docstring>
            The registered URI
        </tp:docstring>
    </arg>
    <arg type="i" name="status">
        <tp:docstring>
            Is the URI present or not
        </tp:docstring>
    </arg>
    <arg type="s" name="lineStatus">
        <tp:docstring>
            A string containing informations from the user (human readable)
        </tp:docstring>
    </arg>
</signal>

<method name="publish" tp:name-for-bindings="publish">
    <tp:added version="1.3.0"/>
    <arg type="s" name="accountID" direction="in">
        <tp:docstring>
            The account from which the presence will be emitted
        </tp:docstring>
    </arg>
    <arg type="b" name="status" direction="in">
        <tp:docstring>
            Is this account present or not
        </tp:docstring>
    </arg>
    <arg type="s" name="note" direction="in">
        <tp:docstring>
            A message transmitted by the server to other users
        </tp:docstring>
    </arg>
</method>

Are the main APIs for clients. subscribeBuddy will listen on the DHT to detect presence changes and newBuddyNotification will be sent whenever a new status is detected:

• The status sent to the client is now 0=offline (no device found on the DHT), 1=dht_presence (at least a device is found on the DHT), 2=connected (with a TCP + SIP channel, so ready to exchange data).

• lineStatus will contain any custom status sent by the peer (e.g. Lunch Time!)

publish is used for publishing a custom note (status is ignored for Jami accounts, note will contain the custom status).

RFC3863 is used to send status over the SIP connection.

Anmodning i afvækst

Send en anmodning

Todo-behovets anmodning

Endelig, når tillidsforespørgslen er udarbejdet, kan vi presse anmodningen til følgende hash: InfoHash("inbox:" + deviceId)

Følgende kode anvendes i daemon:

dht_.putEncrypted(dht::InfoHash::get("inbox:"+dev.toString()), dev, dht::TrustRequest(DHT_TYPE_NS, payload));

Modtagelse af en anmodning

** TODO**

(Akkcept/Blokering/Undtagelse)

Daemon API

Alle metoder til at følge en veninds tilstedeværelse findes i PresenceManager såsom:

<signal name="newBuddyNotification" tp:name-for-bindings="newBuddyNotification">
    <tp:added version="1.3.0"/>
    <tp:docstring>
        Notify when a registered presence uri presence informations changes
    </tp:docstring>
    <arg type="s" name="accountID">
        <tp:docstring>
            The associated account
        </tp:docstring>
    </arg>
    <arg type="s" name="buddyUri">
        <tp:docstring>
            The registered URI
        </tp:docstring>
    </arg>
    <arg type="b" name="status">
        <tp:docstring>
            Is the URI present or not
        </tp:docstring>
    </arg>
    <arg type="s" name="lineStatus">
        <tp:docstring>
            A string containing informations from the user (human readable)
        </tp:docstring>
    </arg>
</signal>

Alle metoder og signaler, der anvendes til at administrere tillidsforespørgsler og kontakter, findes i ConfigurationManager, f.eks.:

<method name="getTrustRequests" tp:name-for-bindings="getTrustRequests">
    <tp:added version="2.2.0"/>
    <arg type="s" name="accountID" direction="in">
    </arg>
    <annotation name="org.qtproject.QtDBus.QtTypeName.Out0" value="VectorMapStringString"/>
    <arg type="aa{ss}" name="requests" direction="out" >
        <tp:docstring>
            A list of contact request details. Details:
            - from: account ID of sender
            - received: UNIX timestamp of reception date
            - payload: attached payload
        </tp:docstring>
    </arg>
</method>

<method name="acceptTrustRequest" tp:name-for-bindings="acceptTrustRequest">
    <tp:added version="2.2.0"/>
    <arg type="s" name="accountID" direction="in">
    </arg>
    <arg type="s" name="from" direction="in">
    </arg>
    <arg type="b" name="success" direction="out" tp:type="Boolean">
        <tp:docstring>
            True if the operation succeeded.
        </tp:docstring>
    </arg>
</method>

<method name="discardTrustRequest" tp:name-for-bindings="discardTrustRequest">
    <tp:added version="2.2.0"/>
    <arg type="s" name="accountID" direction="in">
    </arg>
    <arg type="s" name="from" direction="in">
    </arg>
    <arg type="b" name="success" direction="out" tp:type="Boolean">
        <tp:docstring>
            True if the operation succeeded.
        </tp:docstring>
    </arg>
</method>

<signal name="incomingTrustRequest" tp:name-for-bindings="incomingTrustRequest">
    <tp:added version="2.2.0"/>
    <tp:docstring>
        Notify clients that a new contact request has been received.
    </tp:docstring>
    <arg type="s" name="accountID">
    </arg>
    <arg type="s" name="from">
    </arg>
    <arg type="ay" name="payload">
    </arg>
    <arg type="t" name="receiveTime">
    </arg>
</signal>

<method name="sendTrustRequest" tp:name-for-bindings="sendTrustRequest">
    <tp:added version="2.2.0"/>
    <arg type="s" name="accountID" direction="in">
    </arg>
    <arg type="s" name="to" direction="in">
    </arg>
    <arg type="ay" name="payload" direction="in">
    </arg>
</method>

<method name="addContact" tp:name-for-bindings="addContact">
    <tp:added version="3.0.0"/>
    <arg type="s" name="accountID" direction="in">
    </arg>
    <arg type="s" name="uri" direction="in">
    </arg>
</method>

<method name="removeContact" tp:name-for-bindings="removeContact">
    <tp:added version="3.0.0"/>
    <arg type="s" name="accountID" direction="in">
    </arg>
    <arg type="s" name="uri" direction="in">
    </arg>
    <arg type="b" name="ban" direction="in" tp:type="Boolean">
        <tp:docstring>
            True if the the contact should be banned.
            If false, the contact is removed from the contact list (banned or not).
        </tp:docstring>
    </arg>
</method>

Hvis du vil have nogle eksempler, anvendes disse metoder i contactmodel.cpp i LRC.