Rework writing CAN message on CAN buses.
[apps/agl-service-can-low-level.git] / low-can-binding / binding / low-can-cb.cpp
index eb91c21..3cb61c6 100644 (file)
  */
 
 #include "low-can-hat.hpp"
+#include "low-can-apidef.h"
 
 #include <map>
 #include <queue>
 #include <mutex>
 #include <vector>
 #include <thread>
-#include <json-c/json.h>
+#include <wrap-json.h>
 #include <systemd/sd-event.h>
 
 #include "openxc.pb.h"
@@ -36,7 +37,6 @@
 #include "../diagnostic/diagnostic-message.hpp"
 #include "../utils/openxc-utils.hpp"
 
-
 ///******************************************************************************
 ///
 ///            SystemD event loop Callbacks
 
 void on_no_clients(std::shared_ptr<low_can_subscription_t> can_subscription, uint32_t pid, std::map<int, std::shared_ptr<low_can_subscription_t> >& s)
 {
+       bool is_permanent_recurring_request = false;
+
        if( ! can_subscription->get_diagnostic_message().empty() && can_subscription->get_diagnostic_message(pid) != nullptr)
        {
                DiagnosticRequest diag_req = can_subscription->get_diagnostic_message(pid)->build_diagnostic_request();
                active_diagnostic_request_t* adr = application_t::instance().get_diagnostic_manager().find_recurring_request(diag_req);
                if( adr != nullptr)
-                       application_t::instance().get_diagnostic_manager().cleanup_request(adr, true);
+               {
+                       is_permanent_recurring_request = adr->get_permanent();
+
+                       if(! is_permanent_recurring_request)
+                               application_t::instance().get_diagnostic_manager().cleanup_request(adr, true);
+               }
        }
 
-       on_no_clients(can_subscription, s);
+       if(! is_permanent_recurring_request)
+               on_no_clients(can_subscription, s);
 }
 
 void on_no_clients(std::shared_ptr<low_can_subscription_t> can_subscription, std::map<int, std::shared_ptr<low_can_subscription_t> >& s)
@@ -101,13 +109,14 @@ int read_message(sd_event_source *event_source, int fd, uint32_t revents, void *
 ///
 ///*******************************************************************************/
 
-static int make_subscription_unsubscription(struct afb_req request,
-                                                                                       std::shared_ptr<low_can_subscription_t>& can_subscription,
-                                                                                       std::map<int, std::shared_ptr<low_can_subscription_t> >& s,
-                                                                                       bool subscribe)
+static int make_subscription_unsubscription(afb_req_t request,
+                                           std::shared_ptr<low_can_subscription_t>& can_subscription,
+                                           std::map<int, std::shared_ptr<low_can_subscription_t> >& s,
+                                           bool subscribe)
 {
-       /* Make the subscription or unsubscription to the event */
-       if (((subscribe ? afb_req_subscribe : afb_req_unsubscribe)(request, s[can_subscription->get_index()]->get_event())) < 0)
+       /* Make the subscription or unsubscription to the event (if request is not null) */
+       if(request &&
+          ((subscribe ? afb_req_subscribe : afb_req_unsubscribe)(request, s[can_subscription->get_index()]->get_event())) < 0)
        {
                AFB_ERROR("Operation goes wrong for signal: %s", can_subscription->get_name().c_str());
                return -1;
@@ -116,7 +125,7 @@ static int make_subscription_unsubscription(struct afb_req request,
 }
 
 static int create_event_handle(std::shared_ptr<low_can_subscription_t>& can_subscription,
-                                                       std::map<int, std::shared_ptr<low_can_subscription_t> >& s)
+                              std::map<int, std::shared_ptr<low_can_subscription_t> >& s)
 {
        int sub_index = can_subscription->get_index();
        can_subscription->set_event(afb_daemon_make_event(can_subscription->get_name().c_str()));
@@ -129,13 +138,13 @@ static int create_event_handle(std::shared_ptr<low_can_subscription_t>& can_subs
        return 0;
 }
 
-/// @brief Will determine if it is needed or not to create the event handle and checks it to be sure that
-/// we got a valid afb_event to get subscribe or unsubscribe. Then launch the subscription or unsubscription
+/// @brief This will determine if an event handle needs to be created and checks if
+/// we got a valid afb_event to get subscribe or unsubscribe. After that launch the subscription or unsubscription
 /// against the application framework using that event handle.
-static int subscribe_unsubscribe_signal(struct afb_req request,
-                                                                               bool subscribe,
-                                                                               std::shared_ptr<low_can_subscription_t>& can_subscription,
-                                                                               std::map<int, std::shared_ptr<low_can_subscription_t> >& s)
+static int subscribe_unsubscribe_signal(afb_req_t request,
+                                       bool subscribe,
+                                       std::shared_ptr<low_can_subscription_t>& can_subscription,
+                                       std::map<int, std::shared_ptr<low_can_subscription_t> >& s)
 {
        int ret = -1;
        int sub_index = can_subscription->get_index();
@@ -152,13 +161,12 @@ static int subscribe_unsubscribe_signal(struct afb_req request,
        else
        {
                /* Event doesn't exist , so let's create it */
-               can_subscription->set_event({nullptr, nullptr});
                s[sub_index] = can_subscription;
                ret = create_event_handle(can_subscription, s);
        }
 
-       // Check whether or not the event handler has been correctly created and
-       // make the subscription/unsubscription operation is so.
+       // Checks if the event handler is correctly created, if it is, it
+       // performs the subscription or unsubscription operations.
        if (ret < 0)
                return ret;
        return make_subscription_unsubscription(request, can_subscription, s, subscribe);
@@ -175,11 +183,12 @@ static int add_to_event_loop(std::shared_ptr<low_can_subscription_t>& can_subscr
                        can_subscription.get()));
 }
 
-static int subscribe_unsubscribe_diagnostic_messages(struct afb_req request,
-                                                                                                       bool subscribe,
-                                                                                                       std::vector<std::shared_ptr<diagnostic_message_t> > diagnostic_messages,
-                                                                                                       struct event_filter_t& event_filter,
-                                                                                                       std::map<int, std::shared_ptr<low_can_subscription_t> >& s)
+static int subscribe_unsubscribe_diagnostic_messages(afb_req_t request,
+                                                    bool subscribe,
+                                                    std::vector<std::shared_ptr<diagnostic_message_t> > diagnostic_messages,
+                                                    struct event_filter_t& event_filter,
+                                                    std::map<int, std::shared_ptr<low_can_subscription_t> >& s,
+                                                    bool perm_rec_diag_req)
 {
        int rets = 0;
        application_t& app = application_t::instance();
@@ -188,20 +197,22 @@ static int subscribe_unsubscribe_diagnostic_messages(struct afb_req request,
        for(const auto& sig : diagnostic_messages)
        {
                DiagnosticRequest* diag_req = new DiagnosticRequest(sig->build_diagnostic_request());
-               event_filter.frequency = std::isnan(event_filter.frequency) ? sig->get_frequency() : event_filter.frequency;
+               event_filter.frequency = event_filter.frequency == 0 ? sig->get_frequency() : event_filter.frequency;
                std::shared_ptr<low_can_subscription_t> can_subscription;
 
                auto it =  std::find_if(s.begin(), s.end(), [&sig](std::pair<int, std::shared_ptr<low_can_subscription_t> > sub){ return (! sub.second->get_diagnostic_message().empty());});
                can_subscription = it != s.end() ?
                        it->second :
                        std::make_shared<low_can_subscription_t>(low_can_subscription_t(event_filter));
-               // If the requested diagnostic message isn't supported by the car then unsubcribe it
-               // no matter what we want, worse case will be a fail unsubscription but at least we don't
+               // If the requested diagnostic message is not supported by the car then unsubcribe it
+               // no matter what we want, worst case will be a failed unsubscription but at least we won't
                // poll a PID for nothing.
-               //TODO: Adding callback requesting ignition status:     diag_req, sig.c_str(), false, diagnostic_message_t::decode_obd2_response, diagnostic_message_t::check_ignition_status, frequency);
                if(sig->get_supported() && subscribe)
                {
-                       diag_m.add_recurring_request(diag_req, sig->get_name().c_str(), false, sig->get_decoder(), sig->get_callback(), event_filter.frequency);
+                       if (!app.isEngineOn())
+                               AFB_WARNING("signal: Engine is off, %s won't received responses until it's on",  sig->get_name().c_str());
+
+                       diag_m.add_recurring_request(diag_req, sig->get_name().c_str(), false, sig->get_decoder(), sig->get_callback(), event_filter.frequency, perm_rec_diag_req);
                        if(can_subscription->create_rx_filter(sig) < 0)
                                {return -1;}
                        AFB_DEBUG("Signal: %s subscribed", sig->get_name().c_str());
@@ -233,17 +244,16 @@ static int subscribe_unsubscribe_diagnostic_messages(struct afb_req request,
        return rets;
 }
 
-// TODO: Create separate subscrition object if event_filter isn't the same.
-static int subscribe_unsubscribe_can_signals(struct afb_req request,
-                                                                                       bool subscribe,
-                                                                                       std::vector<std::shared_ptr<can_signal_t> > can_signals,
-                                                                                       struct event_filter_t& event_filter,
-                                                                                       std::map<int, std::shared_ptr<low_can_subscription_t> >& s)
+static int subscribe_unsubscribe_can_signals(afb_req_t request,
+                                            bool subscribe,
+                                            std::vector<std::shared_ptr<can_signal_t> > can_signals,
+                                            struct event_filter_t& event_filter,
+                                            std::map<int, std::shared_ptr<low_can_subscription_t> >& s)
 {
        int rets = 0;
        for(const auto& sig: can_signals)
        {
-               auto it =  std::find_if(s.begin(), s.end(), [&sig](std::pair<int, std::shared_ptr<low_can_subscription_t> > sub){ return sub.second->get_can_signal() == sig; });
+               auto it =  std::find_if(s.begin(), s.end(), [&sig, &event_filter](std::pair<int, std::shared_ptr<low_can_subscription_t> > sub){ return sub.second->is_signal_subscription_corresponding(sig, event_filter) ; });
                std::shared_ptr<low_can_subscription_t> can_subscription;
                if(it != s.end())
                {
@@ -270,16 +280,16 @@ static int subscribe_unsubscribe_can_signals(struct afb_req request,
 ///
 /// @brief subscribe to all signals in the vector signals
 ///
-/// @param[in] afb_req request : contain original request use to subscribe or unsubscribe
-/// @param[in] subscribe boolean value used to chose between a subscription operation or an unsubscription
+/// @param[in] afb_req request : contains original request use to subscribe or unsubscribe
+/// @param[in] subscribe boolean value, which chooses between a subscription operation or an unsubscription
 /// @param[in] signals -  struct containing vectors with can_signal_t and diagnostic_messages to subscribe
 ///
 /// @return Number of correctly subscribed signal
 ///
-static int subscribe_unsubscribe_signals(struct afb_req request,
-                                                                               bool subscribe,
-                                                                               const struct utils::signals_found& signals,
-                                                                               struct event_filter_t& event_filter)
+static int subscribe_unsubscribe_signals(afb_req_t request,
+                                        bool subscribe,
+                                        const struct utils::signals_found& signals,
+                                        struct event_filter_t& event_filter)
 {
        int rets = 0;
        utils::signals_manager_t& sm = utils::signals_manager_t::instance();
@@ -287,16 +297,16 @@ static int subscribe_unsubscribe_signals(struct afb_req request,
        std::lock_guard<std::mutex> subscribed_signals_lock(sm.get_subscribed_signals_mutex());
        std::map<int, std::shared_ptr<low_can_subscription_t> >& s = sm.get_subscribed_signals();
 
-       rets += subscribe_unsubscribe_diagnostic_messages(request, subscribe, signals.diagnostic_messages, event_filter, s);
+       rets += subscribe_unsubscribe_diagnostic_messages(request, subscribe, signals.diagnostic_messages, event_filter, s, false);
        rets += subscribe_unsubscribe_can_signals(request, subscribe, signals.can_signals, event_filter, s);
 
        return rets;
 }
 
-static int one_subscribe_unsubscribe(struct afb_req request,
-                                                                       bool subscribe,
-                                                                       const std::string& tag,
-                                                                       json_object* args)
+static int one_subscribe_unsubscribe(afb_req_t request,
+                                    bool subscribe,
+                                    const std::string& tag,
+                                    json_object* args)
 {
        int ret = 0;
        struct event_filter_t event_filter;
@@ -308,22 +318,13 @@ static int one_subscribe_unsubscribe(struct afb_req request,
        {
                if (json_object_object_get_ex(filter, "frequency", &obj)
                && (json_object_is_type(obj, json_type_double) || json_object_is_type(obj, json_type_int)))
-               {
-                       event_filter.frequency = (float)json_object_get_double(obj);
-                       ret += 1;
-               }
+                       {event_filter.frequency = (float)json_object_get_double(obj);}
                if (json_object_object_get_ex(filter, "min", &obj)
                && (json_object_is_type(obj, json_type_double) || json_object_is_type(obj, json_type_int)))
-               {
-                       event_filter.min = (float)json_object_get_double(obj);
-                       ret += 2;
-               }
+                       {event_filter.min = (float)json_object_get_double(obj);}
                if (json_object_object_get_ex(filter, "max", &obj)
                && (json_object_is_type(obj, json_type_double) || json_object_is_type(obj, json_type_int)))
-               {
-                       event_filter.max = (float)json_object_get_double(obj);
-                       ret += 4;
-               }
+                       {event_filter.max = (float)json_object_get_double(obj);}
        }
 
        // subscribe or unsubscribe
@@ -339,14 +340,12 @@ static int one_subscribe_unsubscribe(struct afb_req request,
 
        return ret;
 }
-
-static void do_subscribe_unsubscribe(struct afb_req request, bool subscribe)
+static int process_one_subscribe_args(afb_req_t request, bool subscribe, json_object *args)
 {
-       int i, n, rc, rc2;
-       struct json_object *args, *event, *x;
-
-       args = afb_req_json(request);
-       if (args == NULL || !json_object_object_get_ex(args, "event", &event))
+       int rc = 0, rc2=0;
+       json_object *x = nullptr, *event = nullptr;
+       if(args == NULL ||
+               !json_object_object_get_ex(args, "event", &event))
        {
                rc = one_subscribe_unsubscribe(request, subscribe, "*", args);
        }
@@ -356,9 +355,7 @@ static void do_subscribe_unsubscribe(struct afb_req request, bool subscribe)
        }
        else
        {
-               rc = 0;
-               n = json_object_array_length(event);
-               for (i = 0 ; i < n ; i++)
+               for (int i = 0 ; i < json_object_array_length(event); i++)
                {
                        x = json_object_array_get_idx(event, i);
                        rc2 = one_subscribe_unsubscribe(request, subscribe, json_object_get_string(x), args);
@@ -366,6 +363,27 @@ static void do_subscribe_unsubscribe(struct afb_req request, bool subscribe)
                                rc = rc2 >= 0 ? rc + rc2 : rc2;
                }
        }
+       return rc;
+}
+
+static void do_subscribe_unsubscribe(afb_req_t request, bool subscribe)
+{
+       int rc = 0;
+       struct json_object *args, *x;
+
+       args = afb_req_json(request);
+       if (json_object_get_type(args) == json_type_array)
+       {
+               for(int i = 0; i < json_object_array_length(args); i++)
+               {
+                       x = json_object_array_get_idx(args, i);
+                       rc += process_one_subscribe_args(request, subscribe, x);
+               }
+       }
+       else
+       {
+               rc += process_one_subscribe_args(request, subscribe, args);
+       }
 
        if (rc >= 0)
                afb_req_success(request, NULL, NULL);
@@ -373,24 +391,28 @@ static void do_subscribe_unsubscribe(struct afb_req request, bool subscribe)
                afb_req_fail(request, "error", NULL);
 }
 
-void auth(struct afb_req request)
+void auth(afb_req_t request)
 {
        afb_req_session_set_LOA(request, 1);
        afb_req_success(request, NULL, NULL);
 }
 
-void subscribe(struct afb_req request)
+void subscribe(afb_req_t request)
 {
        do_subscribe_unsubscribe(request, true);
 }
 
-void unsubscribe(struct afb_req request)
+void unsubscribe(afb_req_t request)
 {
        do_subscribe_unsubscribe(request, false);
 }
 
 static int send_frame(const std::string& bus_name, const struct can_frame& cf)
 {
+       if(bus_name.empty()) {
+               return -1;
+       }
+
        std::map<std::string, std::shared_ptr<low_can_socket_t> >& cd = application_t::instance().get_can_devices();
 
        if( cd.count(bus_name) == 0)
@@ -399,109 +421,146 @@ static int send_frame(const std::string& bus_name, const struct can_frame& cf)
        return cd[bus_name]->tx_send(cf, bus_name);
 }
 
-static int write_raw_frame(const std::string& bus_name, uint32_t can_id, uint8_t can_dlc, struct json_object* can_data)
+static void write_raw_frame(afb_req_t request, const std::string& bus_name, json_object *json_value)
 {
-       int rc = 0;
        struct can_frame cf;
+       struct json_object *json_can_data = nullptr;
 
        ::memset(&cf, 0, sizeof(cf));
 
-       cf.can_id = can_id;
-       cf.can_dlc = can_dlc;
-
-       struct json_object *x;
-       int n = json_object_array_length(can_data);
-       if(n <= 8)
+       if(! wrap_json_unpack(json_value, "{sF, sF, so !}",
+                             "can_id", &cf.can_id,
+                             "can_dlc", &cf.can_dlc,
+                             "can_data", &json_can_data))
        {
-               for (int i = 0 ; i < n ; i++)
+               struct json_object *one_can_data;
+               size_t n = json_object_array_length(json_can_data);
+
+               if(n <= 8 && n > 0)
                {
-                       x = json_object_array_get_idx(can_data, i);
-                       cf.data[i] = json_object_get_type(x) == json_type_int ? (uint8_t)json_object_get_int(x) : 0;
+                       for (int i = 0 ; i < n ; i++)
+                       {
+                               one_can_data = json_object_array_get_idx(json_can_data, i);
+                               cf.data[i] = json_object_get_type(one_can_data) == json_type_int ? (uint8_t)json_object_get_int(one_can_data) : 0;
+                       }
+               }
+               else
+               {
+                       afb_req_fail(request, "Error", "Data array must hold 1 to 8 values.");
+                       return;
                }
-       }
 
-       const std::string found_device = application_t::instance().get_can_bus_manager().get_can_device_name(bus_name);
-       if( ! found_device.empty())
-       {
-               rc = send_frame(found_device, cf);
+               if(! send_frame(application_t::instance().get_can_bus_manager().get_can_device_name(bus_name), cf))
+                       afb_req_success(request, nullptr, "Message correctly sent");
+               else
+                       afb_req_fail(request, "Error", "sending the message. See the log for more details.");
+
+               return;
        }
 
-       return rc;
+       afb_req_fail(request, "Error", "Frame object malformed (must be \n \"frame\": {\"can_id\": int, \"can_dlc\": int, \"can_data\": [ int, int , int, int ,int , int ,int ,int]}");
 }
-static int write_signal(const std::string& name, uint64_t value)
+
+static void write_signal(afb_req_t request, const std::string& name, json_object *json_value)
 {
-       int rc = 0;
        struct can_frame cf;
        struct utils::signals_found sf;
+       signal_encoder encoder = nullptr;
+       bool send = true;
 
        ::memset(&cf, 0, sizeof(cf));
 
        openxc_DynamicField search_key = build_DynamicField(name);
        sf = utils::signals_manager_t::instance().find_signals(search_key);
+       openxc_DynamicField dynafield_value = build_DynamicField(json_value);
 
        if (sf.can_signals.empty())
        {
-               AFB_WARNING("No signal(s) found for %s. Message not sent.", name.c_str());
-               rc = -1;
+               afb_req_fail_f(request, "No signal(s) found for %s. Message not sent.", name.c_str());
+               return;
        }
-       else
+
+       std::shared_ptr<can_signal_t>& sig = sf.can_signals[0];
+       if(! sig->get_writable())
        {
-               for(const auto& sig: sf.can_signals)
-               {
-                       if(sig->get_writable())
-                       {
-                               cf = encoder_t::build_frame(sig, value);
-                               const std::string bus_name = sig->get_message()->get_bus_device_name();
-                               rc = send_frame(bus_name, cf);
-                       }
-                       else
-                               {AFB_NOTICE("%s isn't writable. Message not sent.", sig->get_name().c_str());}
-               }
+               afb_req_fail_f(request, "%s isn't writable. Message not sent.", sig->get_name().c_str());
+               return;
        }
 
-       return rc;
+       uint64_t value = (encoder = sig->get_encoder()) ?
+                       encoder(*sig, dynafield_value, &send) :
+                       encoder_t::encode_DynamicField(*sig, dynafield_value, &send);
+
+       if(! send_frame(sig->get_message()->get_bus_device_name(), encoder_t::build_frame(sig, value)) &&
+               send)
+               afb_req_success(request, nullptr, "Message correctly sent");
+       else
+               afb_req_fail(request, "Error", "Sending the message. See the log for more details.");
 }
 
-void write(struct afb_req request)
+void write(afb_req_t request)
 {
-       int rc = 0;
-       struct json_object* args = nullptr,
-               *json_name = nullptr,
-               *json_value = nullptr;
+       struct json_object* args = nullptr, *json_value = nullptr;
+       const char *name = nullptr;
 
        args = afb_req_json(request);
 
        // Process about Raw CAN message on CAN bus directly
-       if (args != NULL &&
-               (json_object_object_get_ex(args, "bus_name", &json_name) && json_object_is_type(json_name, json_type_string) ) &&
-               (json_object_object_get_ex(args, "frame", &json_value) && json_object_is_type(json_value, json_type_object) ))
-       {
-               struct json_object* json_can_id = nullptr,
-                       *json_can_dlc = nullptr,
-                       *json_can_data = nullptr;
+       if (args != NULL && ! wrap_json_unpack(args, "{ss, so !}",
+                                              "bus_name", &name,
+                                              "frame", &json_value))
+               write_raw_frame(request, name, json_value);
 
-               if( (json_object_object_get_ex(json_value, "can_id", &json_can_id) && (json_object_is_type(json_can_id, json_type_double) || json_object_is_type(json_can_id, json_type_int))) &&
-                       (json_object_object_get_ex(json_value, "can_dlc", &json_can_dlc) && (json_object_is_type(json_can_dlc, json_type_double) || json_object_is_type(json_can_dlc, json_type_int))) &&
-                       (json_object_object_get_ex(json_value, "can_data", &json_can_data) && json_object_is_type(json_can_data, json_type_array) ))
-               {
-                       write_raw_frame(json_object_get_string(json_name),
-                               json_object_get_int(json_can_id),
-                               (uint8_t)json_object_get_int(json_can_dlc),
-                               json_can_data);
-               }
-               else
-               {
-                       AFB_ERROR("Frame object malformed (must be \n \"frame\": {\"can_id\": int, \"can_dlc\": int, \"can_data\": [ int, int , int, int ,int , int ,int ,int]}");
-                       rc = -1;
-               }
-       }
        // Search signal then encode value.
        else if(args != NULL &&
-               (json_object_object_get_ex(args, "signal_name", &json_name) && json_object_is_type(json_name, json_type_string)) &&
-               (json_object_object_get_ex(args, "signal_value", &json_value) && (json_object_is_type(json_value, json_type_double) || json_object_is_type(json_value, json_type_int))))
+               ! wrap_json_unpack(args, "{ss, so !}",
+                                  "signal_name", &name,
+                                  "signal_value", &json_value))
+               write_signal(request, std::string(name), json_value);
+       else
+               afb_req_fail(request, "Error", "Request argument malformed");
+}
+
+static struct json_object *get_signals_value(const std::string& name)
+{
+       struct utils::signals_found sf;
+       struct json_object *ans = nullptr;
+
+       openxc_DynamicField search_key = build_DynamicField(name);
+       sf = utils::signals_manager_t::instance().find_signals(search_key);
+
+       if (sf.can_signals.empty())
+       {
+               AFB_WARNING("No signal(s) found for %s.", name.c_str());
+               return NULL;
+       }
+       ans = json_object_new_array();
+       for(const auto& sig: sf.can_signals)
+       {
+               struct json_object *jobj = json_object_new_object();
+               json_object_object_add(jobj, "event", json_object_new_string(sig->get_name().c_str()));
+               json_object_object_add(jobj, "value", json_object_new_double(sig->get_last_value()));
+               json_object_array_add(ans, jobj);
+       }
+
+       return ans;
+}
+void get(afb_req_t request)
+{
+       int rc = 0;
+       struct json_object* args = nullptr,
+               *json_name = nullptr;
+       json_object *ans = nullptr;
+
+       args = afb_req_json(request);
+
+       // Process about Raw CAN message on CAN bus directly
+       if (args != nullptr &&
+               (json_object_object_get_ex(args, "event", &json_name) && json_object_is_type(json_name, json_type_string) ))
        {
-               write_signal(json_object_get_string(json_name),
-                       (uint64_t)json_object_get_double(json_value));
+               ans = get_signals_value(json_object_get_string(json_name));
+               if (!ans)
+                       rc = -1;
        }
        else
        {
@@ -510,7 +569,106 @@ void write(struct afb_req request)
        }
 
        if (rc >= 0)
-               afb_req_success(request, NULL, NULL);
+               afb_req_success(request, ans, NULL);
+       else
+               afb_req_fail(request, "error", NULL);
+}
+
+
+static struct json_object *list_can_message(const std::string& name)
+{
+       struct utils::signals_found sf;
+       struct json_object *ans = nullptr;
+
+       openxc_DynamicField search_key = build_DynamicField(name);
+       sf = utils::signals_manager_t::instance().find_signals(search_key);
+
+       if (sf.can_signals.empty() && sf.diagnostic_messages.empty())
+       {
+               AFB_WARNING("No signal(s) found for %s.", name.c_str());
+               return NULL;
+       }
+       ans = json_object_new_array();
+       for(const auto& sig: sf.can_signals)
+       {
+               json_object_array_add(ans,
+                       json_object_new_string(sig->get_name().c_str()));
+       }
+       for(const auto& sig: sf.diagnostic_messages)
+       {
+               json_object_array_add(ans,
+                       json_object_new_string(sig->get_name().c_str()));
+       }
+
+       return ans;
+}
+
+void list(afb_req_t request)
+{
+       int rc = 0;
+       json_object *ans = nullptr;
+       struct json_object* args = nullptr,
+               *json_name = nullptr;
+       args = afb_req_json(request);
+       const char *name;
+       if ((args != nullptr) &&
+               (json_object_object_get_ex(args, "event", &json_name) && json_object_is_type(json_name, json_type_string)))
+       {
+               name = json_object_get_string(json_name);
+       }
+       else
+       {
+               name = "*";
+       }
+
+       ans = list_can_message(name);
+       if (!ans)
+               rc = -1;
+
+       if (rc >= 0)
+               afb_req_success(request, ans, NULL);
        else
                afb_req_fail(request, "error", NULL);
 }
+
+/// @brief Initialize the binding.
+///
+/// @param[in] service Structure which represent the Application Framework Binder.
+///
+/// @return Exit code, zero if success.
+int init_binding(afb_api_t api)
+{
+       uint32_t ret = 1;
+       can_bus_t& can_bus_manager = application_t::instance().get_can_bus_manager();
+
+       can_bus_manager.set_can_devices();
+       can_bus_manager.start_threads();
+
+       /// Initialize Diagnostic manager that will handle obd2 requests.
+       /// We pass by default the first CAN bus device to its Initialization.
+       /// TODO: be able to choose the CAN bus device that will be use as Diagnostic bus.
+       if(application_t::instance().get_diagnostic_manager().initialize())
+               ret = 0;
+
+       // Add a recurring dignostic message request to get engine speed at all times.
+       openxc_DynamicField search_key = build_DynamicField("diagnostic_messages.engine.speed");
+       struct utils::signals_found sf = utils::signals_manager_t::instance().find_signals(search_key);
+
+       if(sf.can_signals.empty() && sf.diagnostic_messages.size() == 1)
+       {
+               afb_req_t request = nullptr;
+
+               struct event_filter_t event_filter;
+               event_filter.frequency = sf.diagnostic_messages.front()->get_frequency();
+
+               utils::signals_manager_t& sm = utils::signals_manager_t::instance();
+               std::map<int, std::shared_ptr<low_can_subscription_t> >& s = sm.get_subscribed_signals();
+
+               subscribe_unsubscribe_diagnostic_messages(request, true, sf.diagnostic_messages, event_filter, s, true);
+       }
+
+       if(ret)
+               AFB_ERROR("There was something wrong with CAN device Initialization.");
+
+       return ret;
+}