add querier support

README.md

@@ -120,7 +120,16 @@ The `z_pub` should receive message sent by `z_sub`.
 ./z_get
 ```
 
-The `z_get` should receive the data from `z_queryable`.
+### Queryable and Querier Example
+```bash
+./z_queryable
+```
+
+```bash
+./z_querier
+```
+
+The `z_querier` should continuously send queries and receive replies from `z_queryable`.
 
 ### Throughput Examples
 ```bash

docs/api.rst

@@ -27,6 +27,7 @@ API Reference
    scouting
    publish_subscribe
    query_reply
+   matching
    serialization_deserialization
    channels
    interop

docs/matching.rst

@@ -0,0 +1,11 @@
+Matching
+=================
+Classes related to getting information about matching Zenoh entities.
+
+.. doxygenstruct:: zenoh::MatchingStatus
+   :members:
+   :membergroups: Constructors Operators Methods Fields
+
+.. doxygenclass:: zenoh::MatchingListener
+   :members:
+   :membergroups: Constructors Operators Methods

docs/publish_subscribe.rst

@@ -18,7 +18,7 @@ Classes related to publish-subscribe pattern.
 
 .. doxygenclass:: zenoh::Publisher
    :members:
-   :membergroups: Constructors Operators Methods
+   :membergroups: Constructors Operators Methods Fields
 
 .. doxygenclass:: zenoh::Subscriber
    :members:

docs/query_reply.rst

@@ -16,6 +16,10 @@ Query-Reply
 ===========
 Classes related to query-reply pattern.
 
+.. doxygenclass:: zenoh::Querier
+   :members:
+   :membergroups: Constructors Operators Methods Fields
+
 .. doxygenclass:: zenoh::Queryable
    :members:
    :membergroups: Constructors Operators Methods

examples/CMakeLists.txt

@@ -66,6 +66,9 @@ function(add_examples glob mode lib)
 			if(${file} MATCHES ".*liveliness.*$")
 				continue()
 			endif()
+			if(${file} MATCHES ".*querier.*$")
+				continue()
+			endif()
 			if(${file} MATCHES ".*query_sub.*$")
 				continue()
 			endif()

examples/getargs.h

@@ -16,6 +16,7 @@
 #include <cstring>
 #include <iostream>
 #include <string>
+#include <string_view>
 #include <unordered_map>
 #include <vector>
 
@@ -155,4 +156,30 @@ inline zenoh::Config parse_args(int argc, char **argv, const std::vector<CmdArg>
     }
 #endif
     return std::move(config);
+}
+
+zenoh::QueryTarget parse_query_target(std::string_view v) {
+    if (v == "BEST_MATCHING") {
+        return zenoh::QueryTarget::Z_QUERY_TARGET_BEST_MATCHING;
+    } else if (v == "ALL") {
+        return zenoh::QueryTarget::Z_QUERY_TARGET_ALL;
+    } else if (v == "ALL_COMPLETE") {
+        return zenoh::QueryTarget::Z_QUERY_TARGET_ALL_COMPLETE;
+    }
+
+    throw std::runtime_error(std::string("Unsupported QueryTarget: ") + std::string(v));
+}
+
+struct Selector {
+    std::string key_expr;
+    std::string parameters;
+};
+
+Selector parse_selector(const std::string &selector_string) {
+    size_t pos = selector_string.find('?');
+    if (pos == std::string::npos) {
+        return Selector{selector_string, ""};
+    } else {
+        return Selector{selector_string.substr(0, pos), selector_string.substr(pos + 1)};
+    }
 }

examples/universal/z_get.cxx

@@ -25,10 +25,18 @@ using namespace zenoh;
 
 int _main(int argc, char **argv) {
     const char *expr = "demo/example/**";
-    const char *value = "Get from C++";
-    Config config = parse_args(argc, argv, {}, {{"key_expression", &expr}, {"payload_value", &value}});
+    const char *value = nullptr;
+    const char *target = "BEST_MATCHING";
+    const char *timeout = "10000";
 
-    KeyExpr keyexpr(expr);
+    Config config = parse_args(argc, argv, {}, {},
+                               {{"-s", CmdArg{"Query selector (string)", &expr}},
+                                {"-p", CmdArg{"Query payload (string)", &value}},
+                                {"-t", CmdArg{"Query target (BEST_MATCHING | ALL | ALL_COMPLETE)", &target}},
+                                {"-o", CmdArg{"Timeout in ms (number)", &timeout}}});
+    uint64_t timeout_ms = std::stoi(timeout);
+    QueryTarget query_target = parse_query_target(target);
+    Selector selector = parse_selector(expr);
 
     std::cout << "Opening session...\n";
     auto session = Session::open(std::move(config));
@@ -55,14 +63,13 @@ int _main(int argc, char **argv) {
         done_signal.notify_all();
     };
 
-#if __cpp_designated_initializers >= 201707L
-    session.get(keyexpr, "", on_reply, on_done, {.target = Z_QUERY_TARGET_ALL, .payload = Bytes::serialize(value)});
-#else
     Session::GetOptions options;
-    options.target = Z_QUERY_TARGET_ALL;
-    options.payload = value;
-    session.get(keyexpr, "", on_reply, on_done, std::move(options));
-#endif
+    options.target = query_target;
+    if (value != nullptr) {
+        options.payload = value;
+    }
+    options.timeout_ms = timeout_ms;
+    session.get(selector.key_expr, selector.parameters, on_reply, on_done, std::move(options));
 
     std::unique_lock lock(m);
     done_signal.wait(lock, [&done] { return done; });

examples/universal/z_get_attachment.cxx

@@ -25,10 +25,18 @@ using namespace zenoh;
 
 int _main(int argc, char **argv) {
     const char *expr = "demo/example/**";
-    const char *value = "Get from C++";
-    Config config = parse_args(argc, argv, {}, {{"key_expression", &expr}, {"payload value", &value}});
+    const char *value = nullptr;
+    const char *target = "BEST_MATCHING";
+    const char *timeout = "10000";
 
-    KeyExpr keyexpr(expr);
+    Config config = parse_args(argc, argv, {}, {},
+                               {{"-s", CmdArg{"Query selector (string)", &expr}},
+                                {"-p", CmdArg{"Query payload (string)", &value}},
+                                {"-t", CmdArg{"Query target (BEST_MATCHING | ALL | ALL_COMPLETE)", &target}},
+                                {"-o", CmdArg{"Timeout in ms (number)", &timeout}}});
+    uint64_t timeout_ms = std::stoi(timeout);
+    QueryTarget query_target = parse_query_target(target);
+    Selector selector = parse_selector(expr);
 
     printf("Opening session...\n");
     auto session = Session::open(std::move(config));
@@ -66,10 +74,13 @@ int _main(int argc, char **argv) {
     std::unordered_map<std::string, std::string> attachment = {{"Source", "C++"}};
 
     Session::GetOptions options;
-    options.target = QueryTarget::Z_QUERY_TARGET_ALL;
-    options.payload = value;
+    options.target = query_target;
+    if (value != nullptr) {
+        options.payload = value;
+    }
+    options.timeout_ms = timeout_ms;
     options.attachment = ext::serialize(attachment);
-    session.get(keyexpr, "", on_reply, on_done, std::move(options));
+    session.get(selector.key_expr, selector.parameters, on_reply, on_done, std::move(options));
 
     std::unique_lock lock(m);
     done_signal.wait(lock, [&done] { return done; });

examples/universal/z_get_channel.cxx

@@ -23,24 +23,31 @@ using namespace zenoh;
 
 int _main(int argc, char **argv) {
     const char *expr = "demo/example/**";
-    const char *value = "Get from C++";
-    Config config = parse_args(argc, argv, {}, {{"key_expression", &expr}, {"payload value", &value}});
+    const char *value = nullptr;
+    const char *target = "BEST_MATCHING";
+    const char *timeout = "10000";
 
-    KeyExpr keyexpr(expr);
+    Config config = parse_args(argc, argv, {}, {},
+                               {{"-s", CmdArg{"Query selector (string)", &expr}},
+                                {"-p", CmdArg{"Query payload (string)", &value}},
+                                {"-t", CmdArg{"Query target (BEST_MATCHING | ALL | ALL_COMPLETE)", &target}},
+                                {"-o", CmdArg{"Timeout in ms (number)", &timeout}}});
+    uint64_t timeout_ms = std::stoi(timeout);
+    QueryTarget query_target = parse_query_target(target);
+    Selector selector = parse_selector(expr);
 
     std::cout << "Opening session...\n";
     auto session = Session::open(std::move(config));
 
     std::cout << "Sending Query '" << expr << "'...\n";
-#if __cpp_designated_initializers >= 201707L
-    auto replies = session.get(keyexpr, "", channels::FifoChannel(16),
-                               {.target = QueryTarget::Z_QUERY_TARGET_ALL, .payload = value});
-#else
+
     Session::GetOptions options;
-    options.target = QueryTarget::Z_QUERY_TARGET_ALL;
-    options.payload = value;
-    auto replies = session.get(keyexpr, "", channels::FifoChannel(16), std::move(options));
-#endif
+    options.target = query_target;
+    if (value != nullptr) {
+        options.payload = value;
+    }
+    options.timeout_ms = timeout_ms;
+    auto replies = session.get(selector.key_expr, selector.parameters, channels::FifoChannel(16), std::move(options));
 
     for (auto res = replies.recv(); std::holds_alternative<Reply>(res); res = replies.recv()) {
         const auto &sample = std::get<Reply>(res).get_ok();

examples/universal/z_get_channel_non_blocking.cxx

@@ -25,24 +25,31 @@ using namespace std::chrono_literals;
 
 int _main(int argc, char **argv) {
     const char *expr = "demo/example/**";
-    const char *value = "Get from C++";
-    Config config = parse_args(argc, argv, {}, {{"key_expression", &expr}, {"payload value", &value}});
+    const char *value = nullptr;
+    const char *target = "BEST_MATCHING";
+    const char *timeout = "10000";
 
-    KeyExpr keyexpr(expr);
+    Config config = parse_args(argc, argv, {}, {},
+                               {{"-s", CmdArg{"Query selector (string)", &expr}},
+                                {"-p", CmdArg{"Query payload (string)", &value}},
+                                {"-t", CmdArg{"Query target (BEST_MATCHING | ALL | ALL_COMPLETE)", &target}},
+                                {"-o", CmdArg{"Timeout in ms (number)", &timeout}}});
+    uint64_t timeout_ms = std::stoi(timeout);
+    QueryTarget query_target = parse_query_target(target);
+
+    Selector selector = parse_selector(expr);
     std::cout << "Opening session...\n";
     auto session = Session::open(std::move(config));
 
     std::cout << "Sending Query '" << expr << "'...\n";
 
-#if __cpp_designated_initializers >= 201707L
-    auto replies = session.get(keyexpr, "", channels::FifoChannel(16),
-                               {.target = QueryTarget::Z_QUERY_TARGET_ALL, .payload = value});
-#else
     Session::GetOptions options;
-    options.target = QueryTarget::Z_QUERY_TARGET_ALL;
-    options.payload = value;
-    auto replies = session.get(keyexpr, "", channels::FifoChannel(16), std::move(options));
-#endif
+    options.target = query_target;
+    if (value != nullptr) {
+        options.payload = value;
+    }
+    options.timeout_ms = timeout_ms;
+    auto replies = session.get(selector.key_expr, selector.parameters, channels::FifoChannel(16), std::move(options));
 
     while (true) {
         auto res = replies.try_recv();

examples/universal/z_pub.cxx

@@ -43,7 +43,7 @@ int _main(int argc, char **argv) {
     Config config = parse_args(argc, argv, {}, {{"key_expression", &keyexpr}, {"payload_value", &value}}
 #if defined(ZENOHCXX_ZENOHC) && defined(Z_FEATURE_UNSTABLE_API)
                                ,
-                               {{"--add-matching-listener", {CmdArg{"", &add_matching_listener, true}}}}
+                               {{"--add-matching-listener", CmdArg{"", &add_matching_listener, true}}}
 #endif
     );
 
@@ -53,15 +53,14 @@ int _main(int argc, char **argv) {
     std::cout << "Declaring Publisher on '" << keyexpr << "'..." << std::endl;
     auto pub = session.declare_publisher(KeyExpr(keyexpr));
 
-    std::cout << "Publisher on '" << keyexpr << "' declared" << std::endl;
 #if defined(ZENOHCXX_ZENOHC) && defined(Z_FEATURE_UNSTABLE_API)
     if (std::string(add_matching_listener) == "true") {
         pub.declare_background_matching_listener(
-            [](const Publisher::MatchingStatus &s) {
+            [](const MatchingStatus &s) {
                 if (s.matching) {
-                    std::cout << "Subscriber matched" << std::endl;
+                    std::cout << "Publisher has matching subscribers." << std::endl;
                 } else {
-                    std::cout << "No subscribers matched" << std::endl;
+                    std::cout << "Publisher has NO MORE matching subscribers." << std::endl;
                 }
             },
             closures::none);
@@ -75,13 +74,10 @@ int _main(int argc, char **argv) {
         ss << "[" << idx << "] " << value;
         auto s = ss.str();
         std::cout << "Putting Data ('" << keyexpr << "': '" << s << "')...\n";
-#if __cpp_designated_initializers >= 201707L
-        pub.put(s, {.encoding = Encoding("text/plain")});
-#else
+
         auto put_options = Publisher::PutOptions{};
         put_options.encoding = Encoding("text/plain");
         pub.put(s, std::move(put_options));
-#endif
     }
     return 0;
 }

examples/universal/z_queryable.cxx

@@ -35,7 +35,9 @@ const char *value = "Queryable from C++ zenoh-pico!";
 const char *locator = nullptr;
 
 int _main(int argc, char **argv) {
-    Config config = parse_args(argc, argv, {}, {{"key_expression", &expr}, {"payload_value", &value}});
+    const char *complete = "false";
+    Config config = parse_args(argc, argv, {}, {{"key_expression", &expr}, {"payload_value", &value}},
+                               {{"--complete", {CmdArg{"", &complete, true}}}});
 
     printf("Opening session...\n");
     auto session = Session::open(std::move(config));
@@ -64,7 +66,9 @@ int _main(int argc, char **argv) {
 
     auto on_drop_queryable = []() { std::cout << "Destroying queryable\n"; };
 
-    auto queryable = session.declare_queryable(keyexpr, on_query, on_drop_queryable);
+    Session::QueryableOptions opts;
+    opts.complete = std::string(complete) == "true";
+    auto queryable = session.declare_queryable(keyexpr, on_query, on_drop_queryable, std::move(opts));
 
     std::cout << "Press CTRL-C to quit...\n";
     while (true) {

examples/universal/z_queryable_attachment.cxx

@@ -35,7 +35,9 @@ const char *value = "Queryable from C++ zenoh-pico!";
 #endif
 
 int _main(int argc, char **argv) {
-    Config config = parse_args(argc, argv, {}, {{"key_expression", &expr}, {"payload_value", &value}});
+    const char *complete = "false";
+    Config config = parse_args(argc, argv, {}, {{"key_expression", &expr}, {"payload_value", &value}},
+                               {{"--complete", {CmdArg{"", &complete, true}}}});
 
     std::cout << "Opening session...\n";
     auto session = Session::open(std::move(config));
@@ -71,7 +73,10 @@ int _main(int argc, char **argv) {
     };
 
     auto on_drop_queryable = []() { std::cout << "Destroying queryable\n"; };
-    auto queryable = session.declare_queryable(keyexpr, on_query, on_drop_queryable);
+
+    Session::QueryableOptions opts;
+    opts.complete = std::string(complete) == "true";
+    auto queryable = session.declare_queryable(keyexpr, on_query, on_drop_queryable, std::move(opts));
 
     printf("Press CTRL-C to quit...\n");
     while (true) {

examples/zenohc/z_pub_shm.cxx

@@ -36,7 +36,7 @@ int _main(int argc, char **argv) {
     Config config = parse_args(argc, argv, {}, {{"key_expression", &keyexpr}, {"payload_value", &value}}
 #if defined(ZENOHCXX_ZENOHC) && defined(Z_FEATURE_UNSTABLE_API)
                                ,
-                               {{"--add-matching-listener", {CmdArg{"", &add_matching_listener, true}}}}
+                               {{"--add-matching-listener", CmdArg{"", &add_matching_listener, true}}}
 #endif
     );
 
@@ -49,7 +49,7 @@ int _main(int argc, char **argv) {
 #if defined(ZENOHCXX_ZENOHC) && defined(Z_FEATURE_UNSTABLE_API)
     if (std::string(add_matching_listener) == "true") {
         pub.declare_background_matching_listener(
-            [](const Publisher::MatchingStatus &s) {
+            [](const MatchingStatus &s) {
                 if (s.matching) {
                     std::cout << "Subscriber matched" << std::endl;
                 } else {