Add JSON output to RC

2 files changed, 99 insertions, 9 deletions

diff --git a/lib/RemoteControl.cpp b/lib/RemoteControl.cpp
index 30dcb60..6e9af20 100644
--- a/lib/RemoteControl.cpp
+++ b/lib/RemoteControl.cpp
@@ -25,6 +25,8 @@
 #include <list>
 #include <string>
 #include <iostream>
+#include <sstream>
+#include <iomanip>
 #include <string>
 #include <algorithm>
 
@@ -102,6 +104,74 @@ std::list< std::vector<std::string> > RemoteControllers::get_param_list_values(c
     return allparams;
 }
 
+
+static std::string escape_json(const std::string &s) {
+    std::ostringstream o;
+    for (auto c = s.cbegin(); c != s.cend(); c++) {
+        switch (*c) {
+        case '"': o << "\\\""; break;
+        case '\\': o << "\\\\"; break;
+        case '\b': o << "\\b"; break;
+        case '\f': o << "\\f"; break;
+        case '\n': o << "\\n"; break;
+        case '\r': o << "\\r"; break;
+        case '\t': o << "\\t"; break;
+        default:
+            if ('\x00' <= *c && *c <= '\x1f') {
+                o << "\\u"
+                  << std::hex << std::setw(4) << std::setfill('0') << static_cast<int>(*c);
+            } else {
+                o << *c;
+            }
+        }
+    }
+    return o.str();
+}
+
+std::string RemoteControllers::get_params_json(const std::string& name) {
+    RemoteControllable* controllable = get_controllable_(name);
+    const auto& values = controllable->get_all_values();
+
+    std::ostringstream ss;
+    ss << "{ ";
+    size_t ix = 0;
+    for (const auto& element : values) {
+        if (ix > 0) {
+            ss << ",";
+        }
+
+        ss << "\"" << escape_json(element.first) << "\": ";
+
+        const auto& value = element.second;
+        if (std::holds_alternative<string>(value)) {
+            ss << "\"" << escape_json(std::get<string>(value)) << "\"";
+        }
+        else if (std::holds_alternative<double>(value)) {
+            ss << std::defaultfloat << std::get<double>(value);
+        }
+        else if (std::holds_alternative<ssize_t>(value)) {
+            ss << std::get<ssize_t>(value);
+        }
+        else if (std::holds_alternative<size_t>(value)) {
+            ss << std::get<size_t>(value);
+        }
+        else if (std::holds_alternative<bool>(value)) {
+            ss << (std::get<bool>(value) ? "true" : "false");
+        }
+        else if (std::holds_alternative<std::nullopt_t>(value)) {
+            ss << "null";
+        }
+        else {
+            throw std::logic_error("variant alternative not handled");
+        }
+
+        ix++;
+    }
+    ss << " }";
+
+    return ss.str();
+}
+
 std::string RemoteControllers::get_param(const std::string& name, const std::string& param) {
     RemoteControllable* controllable = get_controllable_(name);
     return controllable->get_parameter(param);
@@ -427,10 +497,15 @@ void RemoteControllerZmq::recv_all(zmq::socket_t& pSocket, std::vector<std::stri
     bool more = true;
     do {
         zmq::message_t msg;
-        pSocket.recv(msg);
-        std::string incoming((char*)msg.data(), msg.size());
-        message.push_back(incoming);
-        more = msg.more();
+        const auto zresult = pSocket.recv(msg);
+        if (zresult) {
+            std::string incoming((char*)msg.data(), msg.size());
+            message.push_back(incoming);
+            more = msg.more();
+        }
+        else {
+            more = false;
+        }
     } while (more);
 }
 
@@ -532,6 +607,15 @@ void RemoteControllerZmq::process()
                         send_fail_reply(repSocket, err.what());
                     }
                 }
+                else if (msg.size() == 2 && command == "showjson") {
+                    std::string module((char*) msg[1].data(), msg[1].size());
+                    std::string json = rcs.get_params_json(module);
+
+                    zmq::message_t zmsg(json.size());
+                    memcpy(zmsg.data(), json.data(), json.size());
+
+                    repSocket.send(zmsg, zmq::send_flags::none);
+                }
                 else if (msg.size() == 3 && command == "get") {
                     std::string module((char*) msg[1].data(), msg[1].size());
                     std::string parameter((char*) msg[2].data(), msg[2].size());
@@ -561,7 +645,7 @@ void RemoteControllerZmq::process()
                 }
                 else {
                     send_fail_reply(repSocket,
-                            "Unsupported command. commands: list, show, get, set");
+                            "Unsupported command. commands: list, show, get, set, showjson");
                 }
             }
         }
diff --git a/lib/RemoteControl.h b/lib/RemoteControl.h
index 2358b3a..4bc3b68 100644
--- a/lib/RemoteControl.h
+++ b/lib/RemoteControl.h
@@ -3,7 +3,7 @@
    Her Majesty the Queen in Right of Canada (Communications Research
    Center Canada)
 
-   Copyright (C) 2019
+   Copyright (C) 2023
    Matthias P. Braendli, matthias.braendli@mpb.li
 
     http://www.opendigitalradio.org
@@ -36,6 +36,8 @@
 #endif
 
 #include <list>
+#include <unordered_map>
+#include <variant>
 #include <map>
 #include <memory>
 #include <string>
@@ -113,13 +115,16 @@ class RemoteControllable {
             }
 
         /* Base function to set parameters. */
-        virtual void set_parameter(
-                const std::string& parameter,
-                const std::string& value) = 0;
+        virtual void set_parameter(const std::string& parameter, const std::string& value) = 0;
 
         /* Getting a parameter always returns a string. */
         virtual const std::string get_parameter(const std::string& parameter) const = 0;
 
+        using value_t = std::variant<std::string, double, size_t, ssize_t, bool, std::nullopt_t>;
+        using map_t = std::unordered_map<std::string, value_t>;
+
+        virtual const map_t get_all_values() const = 0;
+
     protected:
         std::string m_rc_name;
         std::list< std::vector<std::string> > m_parameters;
@@ -135,6 +140,7 @@ class RemoteControllers {
         void check_faults();
         std::list< std::vector<std::string> > get_param_list_values(const std::string& name);
         std::string get_param(const std::string& name, const std::string& param);
+        std::string get_params_json(const std::string& name);
 
         void set_param(
                 const std::string& name,