Implement the support for adhoc commands

We have two basic example commands. But it’s not entirely finished because
there are some error checks that we don’t do.

ref #2521

8 files changed, 370 insertions, 5 deletions

diff --git a/src/xmpp/adhoc_command.cpp b/src/xmpp/adhoc_command.cpp
new file mode 100644
index 0000000..b880533
--- /dev/null
+++ b/src/xmpp/adhoc_command.cpp
@@ -0,0 +1,82 @@
+#include <xmpp/adhoc_command.hpp>
+
+using namespace std::string_literals;
+
+AdhocCommand::AdhocCommand(std::vector<AdhocStep>&& callbacks, const std::string& name, const bool admin_only):
+  name(name),
+  callbacks(std::move(callbacks)),
+  admin_only(admin_only)
+{
+}
+
+AdhocCommand::~AdhocCommand()
+{
+}
+
+void PingStep1(AdhocSession&, XmlNode& command_node)
+{
+  XmlNode note("note");
+  note["type"] = "info";
+  note.set_inner("Pong");
+  note.close();
+  command_node.add_child(std::move(note));
+}
+
+void HelloStep1(AdhocSession&, XmlNode& command_node)
+{
+  XmlNode x("jabber:x:data:x");
+  x["type"] = "form";
+  XmlNode title("title");
+  title.set_inner("Configure your name.");
+  title.close();
+  x.add_child(std::move(title));
+  XmlNode instructions("instructions");
+  instructions.set_inner("Please provide your name.");
+  instructions.close();
+  x.add_child(std::move(instructions));
+  XmlNode name_field("field");
+  name_field["var"] = "name";
+  name_field["type"] = "text-single";
+  name_field["label"] = "Your name";
+  XmlNode required("required");
+  required.close();
+  name_field.add_child(std::move(required));
+  name_field.close();
+  x.add_child(std::move(name_field));
+  x.close();
+  command_node.add_child(std::move(x));
+}
+
+void HelloStep2(AdhocSession& session, XmlNode& command_node)
+{
+  // Find out if the name was provided in the form.
+  XmlNode* x = command_node.get_child("x", "jabber:x:data");
+  if (x)
+    {
+      XmlNode* name_field = nullptr;
+      for (XmlNode* field: x->get_children("field", "jabber:x:data"))
+        if (field->get_tag("var") == "name")
+          {
+            name_field = field;
+            break;
+          }
+      if (name_field)
+        {
+          XmlNode* value = name_field->get_child("value", "jabber:x:data");
+          if (value)
+            {
+              XmlNode note("note");
+              note["type"] = "info";
+              note.set_inner("Hello "s + value->get_inner() + "!"s);
+              note.close();
+              command_node.delete_all_children();
+              command_node.add_child(std::move(note));
+              return;
+            }
+        }
+    }
+  // TODO insert an error telling the name value is missing.  Also it's
+  // useless to terminate it, since this step is the last of the command
+  // anyway. But this is for the example.
+  session.terminate();
+}
diff --git a/src/xmpp/adhoc_command.hpp b/src/xmpp/adhoc_command.hpp
new file mode 100644
index 0000000..59a3cd6
--- /dev/null
+++ b/src/xmpp/adhoc_command.hpp
@@ -0,0 +1,40 @@
+#ifndef ADHOC_COMMAND_HPP
+# define ADHOC_COMMAND_HPP
+
+/**
+ * Describe an ad-hoc command.
+ *
+ * Can only have zero or one step for now. When execution is requested, it
+ * can return a result immediately, or provide a form to be filled, and
+ * provide a result once the filled form is received.
+ */
+
+#include <xmpp/adhoc_session.hpp>
+
+#include <functional>
+#include <string>
+
+class AdhocCommand
+{
+  friend class AdhocSession;
+public:
+  AdhocCommand(std::vector<AdhocStep>&& callback, const std::string& name, const bool admin_only);
+  ~AdhocCommand();
+
+  const std::string name;
+
+private:
+  /**
+   * A command may have one or more steps. Each step is a different
+   * callback, inserting things into a <command/> XmlNode and calling
+   * methods of an AdhocSession.
+   */
+  std::vector<AdhocStep> callbacks;
+  const bool admin_only;
+};
+
+void PingStep1(AdhocSession& session, XmlNode& command_node);
+void HelloStep1(AdhocSession& session, XmlNode& command_node);
+void HelloStep2(AdhocSession& session, XmlNode& command_node);
+
+#endif // ADHOC_COMMAND_HPP
diff --git a/src/xmpp/adhoc_commands_handler.cpp b/src/xmpp/adhoc_commands_handler.cpp
new file mode 100644
index 0000000..a669ca1
--- /dev/null
+++ b/src/xmpp/adhoc_commands_handler.cpp
@@ -0,0 +1,100 @@
+#include <xmpp/adhoc_commands_handler.hpp>
+#include <xmpp/xmpp_component.hpp>
+
+#include <logger/logger.hpp>
+
+#include <iostream>
+
+AdhocCommandsHandler::AdhocCommandsHandler():
+  commands{
+  {"ping", AdhocCommand({&PingStep1}, "Do a ping", false)},
+  {"hello", AdhocCommand({&HelloStep1, &HelloStep2}, "Receive a custom greeting", false)}
+  }
+{
+}
+
+AdhocCommandsHandler::~AdhocCommandsHandler()
+{
+}
+
+const std::map<const std::string, const AdhocCommand>& AdhocCommandsHandler::get_commands() const
+{
+  return this->commands;
+}
+
+XmlNode&& AdhocCommandsHandler::handle_request(const std::string& executor_jid, XmlNode command_node)
+{
+  // TODO check the type of action. Currently it assumes it is always
+  // 'execute'.
+  std::string action = command_node.get_tag("action");
+  if (action.empty())
+    action = "execute";
+  command_node.del_tag("action");
+
+  const std::string node = command_node.get_tag("node");
+  auto command_it = this->commands.find(node);
+  if (command_it == this->commands.end())
+    {
+      XmlNode error(ADHOC_NS":error");
+      error["type"] = "cancel";
+      XmlNode condition(STANZA_NS":item-not-found");
+      condition.close();
+      error.add_child(std::move(condition));
+      error.close();
+      command_node.add_child(std::move(error));
+    }
+  else
+    {
+      std::string sessionid = command_node.get_tag("sessionid");
+      if (sessionid.empty())
+        {                       // create a new session, with a new id
+          sessionid = XmppComponent::next_id();
+          command_node["sessionid"] = sessionid;
+          this->sessions.emplace(std::piecewise_construct,
+                                 std::forward_as_tuple(sessionid, executor_jid),
+                                 std::forward_as_tuple(command_it->second, executor_jid));
+          // TODO add a timed event to have an expiration date that deletes
+          // this session. We could have a nasty client starting commands
+          // but never finishing the last step, and that would fill the map
+          // with dummy sessions.
+        }
+      auto session_it = this->sessions.find(std::make_pair(sessionid, executor_jid));
+      if (session_it == this->sessions.end())
+        {
+          XmlNode error(ADHOC_NS":error");
+          error["type"] = "modify";
+          XmlNode condition(STANZA_NS":bad-request");
+          condition.close();
+          error.add_child(std::move(condition));
+          error.close();
+          command_node.add_child(std::move(error));
+        }
+      else
+        {
+          // execute the step
+          AdhocSession& session = session_it->second;
+          const AdhocStep& step = session.get_next_step();
+          step(session, command_node);
+          if (session.remaining_steps() == 0 ||
+              session.is_terminated())
+            {
+              this->sessions.erase(session_it);
+              command_node["status"] = "completed";
+            }
+          else
+            {
+              command_node["status"] = "executing";
+              XmlNode actions("actions");
+              XmlNode next("next");
+              next.close();
+              actions.add_child(std::move(next));
+              actions.close();
+              command_node.add_child(std::move(actions));
+            }
+        }
+    }
+  // TODO remove that once we make sure so session can stay there for ever,
+  // by mistake.
+  log_debug("Number of existing sessions: " << this->sessions.size());
+  return std::move(command_node);
+}
diff --git a/src/xmpp/adhoc_commands_handler.hpp b/src/xmpp/adhoc_commands_handler.hpp
new file mode 100644
index 0000000..6e00188
--- /dev/null
+++ b/src/xmpp/adhoc_commands_handler.hpp
@@ -0,0 +1,56 @@
+#ifndef ADHOC_COMMANDS_HANDLER_HPP
+# define ADHOC_COMMANDS_HANDLER_HPP
+
+/**
+ * Manage a list of available AdhocCommands and the list of ongoing
+ * AdhocCommandSessions.
+ */
+
+#include <xmpp/adhoc_command.hpp>
+#include <xmpp/xmpp_stanza.hpp>
+
+#include <utility>
+#include <string>
+#include <map>
+
+class AdhocCommandsHandler
+{
+public:
+  explicit AdhocCommandsHandler();
+  ~AdhocCommandsHandler();
+  /**
+   * Returns the list of available commands.
+   */
+  const std::map<const std::string, const AdhocCommand>& get_commands() const;
+  /**
+   * Find the requested command, create a new session or use an existing
+   * one, and process the request (provide a new form, an error, or a
+   * result).
+   *
+   * Returns a (moved) XmlNode that will be inserted in the iq response. It
+   * should be a <command/> node containing one or more useful children. If
+   * it contains an <error/> node, the iq response will have an error type.
+   *
+   * Takes a copy of the <command/> node so we can actually edit it and use
+   * it as our return value.
+   */
+  XmlNode&& handle_request(const std::string& executor_jid, XmlNode command_node);
+private:
+  /**
+   * The list of all available commands.
+   */
+  const std::map<const std::string, const AdhocCommand> commands;
+  /**
+   * The list of all currently on-going commands.
+   *
+   * Of the form: {{session_id, owner_jid}, session}.
+   */
+  std::map<std::pair<const std::string, const std::string>, AdhocSession> sessions;
+
+  AdhocCommandsHandler(const AdhocCommandsHandler&) = delete;
+  AdhocCommandsHandler(AdhocCommandsHandler&&) = delete;
+  AdhocCommandsHandler& operator=(const AdhocCommandsHandler&) = delete;
+  AdhocCommandsHandler& operator=(AdhocCommandsHandler&&) = delete;
+};
+
+#endif // ADHOC_COMMANDS_HANDLER_HPP
diff --git a/src/xmpp/xmpp_component.cpp b/src/xmpp/xmpp_component.cpp
index 9ac05ac..4c62aa7 100644
--- a/src/xmpp/xmpp_component.cpp
+++ b/src/xmpp/xmpp_component.cpp
@@ -447,6 +447,22 @@ void XmppComponent::handle_iq(const Stanza& stanza)
                 }
             }
         }
+      else if ((query = stanza.get_child("command", ADHOC_NS)))
+        {
+          Stanza response("iq");
+          response["to"] = from;
+          response["from"] = this->served_hostname;
+          response["id"] = id;
+          XmlNode inner_node = this->adhoc_commands_handler.handle_request(from, *query);
+          if (inner_node.get_child("error", ADHOC_NS))
+            response["type"] = "error";
+          else
+            response["type"] = "result";
+          response.add_child(std::move(inner_node));
+          response.close();
+          this->send_stanza(response);
+          stanza_error.disable();
+        }
     }
   else if (type == "get")
     {
@@ -454,8 +470,22 @@ void XmppComponent::handle_iq(const Stanza& stanza)
       if ((query = stanza.get_child("query", DISCO_INFO_NS)))
         { // Disco info
           if (to_str == this->served_hostname)
-            { // On the gateway itself
-              this->send_self_disco_info(id, from);
+            {
+              const std::string node = query->get_tag("node");
+              if (node.empty())
+                {
+                  // On the gateway itself
+                  this->send_self_disco_info(id, from);
+                  stanza_error.disable();
+                }
+            }
+        }
+      else if ((query = stanza.get_child("query", DISCO_ITEMS_NS)))
+        {
+          const std::string node = query->get_tag("node");
+          if (node == ADHOC_NS)
+            {
+              this->send_adhoc_commands_list(id, from);
               stanza_error.disable();
             }
         }
@@ -848,8 +878,7 @@ void XmppComponent::send_self_disco_info(const std::string& id, const std::strin
   identity["name"] = "Biboumi XMPP-IRC gateway";
   identity.close();
   query.add_child(std::move(identity));
-  for (const std::string& ns: {"http://jabber.org/protocol/disco#info",
-                                    "http://jabber.org/protocol/muc"})
+  for (const std::string& ns: {DISCO_INFO_NS, MUC_NS, ADHOC_NS})
     {
       XmlNode feature("feature");
       feature["var"] = ns;
@@ -862,6 +891,31 @@ void XmppComponent::send_self_disco_info(const std::string& id, const std::strin
   this->send_stanza(iq);
 }
 
+void XmppComponent::send_adhoc_commands_list(const std::string& id, const std::string& requester_jid)
+{
+  Stanza iq("iq");
+  iq["type"] = "result";
+  iq["id"] = id;
+  iq["to"] = requester_jid;
+  iq["from"] = this->served_hostname;
+  XmlNode query("query");
+  query["xmlns"] = DISCO_ITEMS_NS;
+  query["node"] = ADHOC_NS;
+  for (const auto& kv: this->adhoc_commands_handler.get_commands())
+    {
+      XmlNode item("item");
+      item["jid"] = this->served_hostname;
+      item["node"] = kv.first;
+      item["name"] = kv.second.name;
+      item.close();
+      query.add_child(std::move(item));
+    }
+  query.close();
+  iq.add_child(std::move(query));
+  iq.close();
+  this->send_stanza(iq);
+}
+
 void XmppComponent::send_iq_version_request(const std::string& from,
                                             const std::string& jid_to)
 {
diff --git a/src/xmpp/xmpp_component.hpp b/src/xmpp/xmpp_component.hpp
index d934704..b234d76 100644
--- a/src/xmpp/xmpp_component.hpp
+++ b/src/xmpp/xmpp_component.hpp
@@ -1,6 +1,7 @@
 #ifndef XMPP_COMPONENT_INCLUDED
 # define XMPP_COMPONENT_INCLUDED
 
+#include <xmpp/adhoc_commands_handler.hpp>
 #include <network/socket_handler.hpp>
 #include <xmpp/xmpp_parser.hpp>
 #include <bridge/bridge.hpp>
@@ -178,6 +179,11 @@ public:
    */
   void send_self_disco_info(const std::string& id, const std::string& jid_to);
   /**
+   * Send the list of all available ad-hoc commands to that JID. The list is
+   * different depending on what JID made the request.
+   */
+  void send_adhoc_commands_list(const std::string& id, const std::string& requester_jid);
+  /**
    * Send an iq version request
    */
   void send_iq_version_request(const std::string& from,
@@ -231,6 +237,7 @@ private:
 
   static unsigned long current_id;
 
+  AdhocCommandsHandler adhoc_commands_handler;
   XmppComponent(const XmppComponent&) = delete;
   XmppComponent(XmppComponent&&) = delete;
   XmppComponent& operator=(const XmppComponent&) = delete;
diff --git a/src/xmpp/xmpp_stanza.cpp b/src/xmpp/xmpp_stanza.cpp
index be9f8ae..c964c64 100644
--- a/src/xmpp/xmpp_stanza.cpp
+++ b/src/xmpp/xmpp_stanza.cpp
@@ -243,6 +243,13 @@ const std::string XmlNode::get_tag(const std::string& name) const
     }
 }
 
+bool XmlNode::del_tag(const std::string& name)
+{
+  if (this->attributes.erase(name) != 0)
+    return true;
+  return false;
+}
+
 std::string& XmlNode::operator[](const std::string& name)
 {
   return this->attributes[name];
diff --git a/src/xmpp/xmpp_stanza.hpp b/src/xmpp/xmpp_stanza.hpp
index cc8d53a..e55d555 100644
--- a/src/xmpp/xmpp_stanza.hpp
+++ b/src/xmpp/xmpp_stanza.hpp
@@ -34,6 +34,21 @@ public:
   {
     node.parent = nullptr;
   }
+  /**
+   * The copy constructor do not copy the children or parent attributes. The
+   * copied node is identical to the original except that it is not attached
+   * to any other node.
+   */
+  XmlNode(const XmlNode& node):
+    name(node.name),
+    parent(nullptr),
+    closed(node.closed),
+    attributes(node.attributes),
+    children{},
+    inner(node.inner),
+    tail(node.tail)
+  {
+  }
 
   ~XmlNode();
 
@@ -104,6 +119,11 @@ public:
    */
   const std::string get_tag(const std::string& name) const;
   /**
+   * Remove the attribute of the node. Does nothing if that attribute is not
+   * present. Returns true if the tag was removed, false if it was absent.
+   */
+  bool del_tag(const std::string& name);
+  /**
    * Use this to set an attribute's value, like node["id"] = "12";
    */
   std::string& operator[](const std::string& name);
@@ -117,7 +137,6 @@ private:
   std::string inner;
   std::string tail;
 
-  XmlNode(const XmlNode&) = delete;
   XmlNode& operator=(const XmlNode&) = delete;
   XmlNode& operator=(XmlNode&&) = delete;
 };