LaunchServer: Discover handlers from *.af files, allow launching based on a known handler

Adds metadata about apps for what file types and protocols they can
handle, then consumes that in the LaunchServer. The LaunchServer can
then use that to offer multiple options for what apps can open a given
URL. Callers can then pass back the handler name to the LaunchServer to
use an alternate app :)

Base/res/apps/Browser.af

@@ -6,3 +6,7 @@ Category=Internet
 [Icons]
 16x16=/res/icons/16x16/app-browser.png
 32x32=/res/icons/32x32/app-browser.png
+
+[Launcher]
+FileTypes=html,md
+Protocols=http,https

Base/res/apps/TextEditor.af

@@ -6,3 +6,6 @@ Category=Utilities
 [Icons]
 16x16=/res/icons/TextEditor16.png
 32x32=/res/icons/32x32/app-texteditor.png
+
+[Launcher]
+FileTypes=txt,md,html

Libraries/LibDesktop/Launcher.cpp

@@ -48,13 +48,13 @@ private:
         : IPC::ServerConnection<LaunchClientEndpoint, LaunchServerEndpoint>(*this, "/tmp/portal/launch")
     {
     }
-    virtual void handle(const Messages::LaunchClient::Dummy&) override { }
+    virtual void handle(const Messages::LaunchClient::Dummy&) override {}
 };
 
-bool Launcher::open(const URL& url)
+bool Launcher::open(const URL& url, const String& handler_name)
 {
     auto connection = LaunchServerConnection::construct();
-    return connection->send_sync<Messages::LaunchServer::OpenUrl>(url.to_string())->response();
+    return connection->send_sync<Messages::LaunchServer::OpenUrl>(url.to_string(), handler_name)->response();
 }
 
 Vector<String> Launcher::get_handlers_for_url(const URL& url)

Libraries/LibDesktop/Launcher.h

@@ -32,7 +32,7 @@ namespace Desktop {
 
 class Launcher {
 public:
-    static bool open(const URL&);
+    static bool open(const URL&, const String& handler_name = {});
     static Vector<String> get_handlers_for_url(const URL&);
 };
 

Services/LaunchServer/ClientConnection.cpp

@@ -56,7 +56,7 @@ OwnPtr<Messages::LaunchServer::GreetResponse> ClientConnection::handle(const Mes
 OwnPtr<Messages::LaunchServer::OpenUrlResponse> ClientConnection::handle(const Messages::LaunchServer::OpenUrl& request)
 {
     URL url(request.url());
-    auto result = Launcher::the().open_url(url);
+    auto result = Launcher::the().open_url(url, request.handler_name());
     return make<Messages::LaunchServer::OpenUrlResponse>(result);
 }
 

Services/LaunchServer/LaunchServer.ipc

@@ -1,6 +1,6 @@
 endpoint LaunchServer = 101
 {
     Greet() => (i32 client_id)
-    OpenUrl(String url) => (bool response)
+    OpenUrl(String url, String handler_name) => (bool response)
     GetHandlersForURL(String url) => (Vector<String> handlers)
 }

Services/LaunchServer/Launcher.cpp

@@ -26,7 +26,9 @@
 
 #include "Launcher.h"
 #include <AK/FileSystemPath.h>
+#include <AK/Function.h>
 #include <LibCore/ConfigFile.h>
+#include <LibCore/DirIterator.h>
 #include <stdio.h>
 #include <sys/stat.h>
 
@@ -47,6 +49,33 @@ Launcher& Launcher::the()
     return *s_the;
 }
 
+void Launcher::load_handlers(const String& af_dir)
+{
+    auto load_hashtable = [](auto& af, auto& key) {
+        HashTable<String> table;
+
+        auto config_value = af->read_entry("Launcher", key, {});
+        for (auto& key : config_value.split(','))
+            table.set(key.to_lowercase());
+
+        return table;
+    };
+
+    Core::DirIterator dt(af_dir, Core::DirIterator::SkipDots);
+    while (dt.has_next()) {
+        auto af_name = dt.next_path();
+        auto af_path = String::format("%s/%s", af_dir.characters(), af_name.characters());
+        auto af = Core::ConfigFile::open(af_path);
+        if (!af->has_key("App", "Name") || !af->has_key("App", "Executable"))
+            continue;
+        auto app_name = af->read_entry("App", "Name");
+        auto app_executable = af->read_entry("App", "Executable");
+        auto file_types = load_hashtable(af, "FileTypes");
+        auto protocols = load_hashtable(af, "Protocols");
+        m_handlers.set(app_executable, { app_name, app_executable, file_types, protocols });
+    }
+}
+
 void Launcher::load_config(const Core::ConfigFile& cfg)
 {
     for (auto key : cfg.keys("FileType")) {
@@ -63,15 +92,35 @@ Vector<String> Launcher::handlers_for_url(const URL& url)
     if (url.protocol() == "file")
         return handlers_for_path(url.path());
 
-    return { m_protocol_handlers.get(url.protocol()).value_or(m_protocol_handlers.get("*").value_or({})) };
+    return handlers_for(url.protocol(), m_protocol_handlers, [](auto& handler, auto& key) {
+        return handler.protocols.contains(key);
+    });
 }
 
-bool Launcher::open_url(const URL& url)
+bool Launcher::open_url(const URL& url, const String& handler_name)
 {
+    if (!handler_name.is_null())
+        return open_with_handler_name(url, handler_name);
+
     if (url.protocol() == "file")
         return open_file_url(url);
 
-    return open_with_handlers(m_protocol_handlers, url.protocol(), url.to_string(), "/bin/Browser");
+    return open_with_user_preferences(m_protocol_handlers, url.protocol(), url.to_string(), "/bin/Browser");
+}
+
+bool Launcher::open_with_handler_name(const URL& url, const String& handler_name)
+{
+    auto handler_optional = m_handlers.get(handler_name);
+    if (!handler_optional.has_value())
+        return false;
+
+    auto& handler = handler_optional.value();
+    String argument;
+    if (url.protocol() == "file")
+        argument = url.path();
+    else
+        argument = url.to_string();
+    return spawn(handler.executable, argument);
 }
 
 bool spawn(String executable, String argument)
@@ -91,14 +140,14 @@ bool spawn(String executable, String argument)
     return true;
 }
 
-bool Launcher::open_with_handlers(const HashMap<String, String>& handlers, const String key, const String argument, const String default_program)
+bool Launcher::open_with_user_preferences(const HashMap<String, String>& user_preferences, const String key, const String argument, const String default_program)
 {
-    auto program_path = handlers.get(key);
+    auto program_path = user_preferences.get(key);
     if (program_path.has_value())
         return spawn(program_path.value(), argument);
 
     // There wasn't a handler for this, so try the fallback instead
-    program_path = handlers.get("*");
+    program_path = user_preferences.get("*");
     if (program_path.has_value())
         return spawn(program_path.value(), argument);
 
@@ -107,6 +156,29 @@ bool Launcher::open_with_handlers(const HashMap<String, String>& handlers, const
     return spawn(default_program, argument);
 }
 
+Vector<String> Launcher::handlers_for(const String& key, HashMap<String, String>& user_preference, Function<bool(Handler&, const String&)> handler_matches)
+{
+    Vector<String> handlers;
+
+    auto user_preferred = user_preference.get(key);
+    if (user_preferred.has_value())
+        handlers.append(user_preferred.value());
+
+    for (auto& handler : m_handlers) {
+        // Skip over the existing item in the list
+        if (user_preferred.has_value() && user_preferred.value() == handler.value.executable)
+            continue;
+        if (handler_matches(handler.value, key))
+            handlers.append(handler.value.executable);
+    }
+
+    auto user_default = user_preference.get("*");
+    if (handlers.size() == 0 && user_default.has_value())
+        handlers.append(user_default.value());
+
+    return handlers;
+}
+
 Vector<String> Launcher::handlers_for_path(const String& path)
 {
     struct stat st;
@@ -120,7 +192,10 @@ Vector<String> Launcher::handlers_for_path(const String& path)
         return { "/bin/FileManager" };
 
     auto extension = FileSystemPath(path).extension().to_lowercase();
-    return { m_file_handlers.get(extension).value_or(m_file_handlers.get("*").value_or({})) };
+
+    return handlers_for(extension, m_file_handlers, [](auto& handler, auto& key) {
+        return handler.file_types.contains(key);
+    });
 }
 
 bool Launcher::open_file_url(const URL& url)
@@ -142,7 +217,6 @@ bool Launcher::open_file_url(const URL& url)
     String extension = {};
     if (extension_parts.size() > 1)
         extension = extension_parts.last();
-    return open_with_handlers(m_file_handlers, extension, url.path(), "/bin/TextEdit");
+    return open_with_user_preferences(m_file_handlers, extension, url.path(), "/bin/TextEdit");
 }
-
 }

Services/LaunchServer/Launcher.h

@@ -27,26 +27,38 @@
 #pragma once
 
 #include <AK/HashMap.h>
+#include <AK/HashTable.h>
 #include <AK/URL.h>
 #include <LibCore/ConfigFile.h>
 
 namespace LaunchServer {
 
+struct Handler {
+    String name;
+    String executable;
+    HashTable<String> file_types;
+    HashTable<String> protocols;
+};
+
 class Launcher {
 public:
     Launcher();
     static Launcher& the();
 
+    void load_handlers(const String& af_dir);
     void load_config(const Core::ConfigFile&);
-    bool open_url(const URL&);
+    bool open_url(const URL&, const String& handler_name);
     Vector<String> handlers_for_url(const URL&);
 
 private:
+    HashMap<String, Handler> m_handlers;
     HashMap<String, String> m_protocol_handlers;
     HashMap<String, String> m_file_handlers;
 
+    Vector<String> handlers_for(const String& key, HashMap<String, String>& user_preferences, Function<bool(Handler&, const String&)> handler_matches);
     Vector<String> handlers_for_path(const String&);
     bool open_file_url(const URL&);
-    bool open_with_handlers(const HashMap<String, String>& handlers, const String key, const String argument, const String default_program);
+    bool open_with_user_preferences(const HashMap<String, String>& user_preferences, const String key, const String argument, const String default_program);
+    bool open_with_handler_name(const URL&, const String& handler_name);
 };
 }

Services/LaunchServer/main.cpp

@@ -42,6 +42,7 @@ int main(int argc, char** argv)
 
     auto launcher = LaunchServer::Launcher();
 
+    launcher.load_handlers("/res/apps");
     launcher.load_config(Core::ConfigFile::get_for_app("LaunchServer"));
 
     if (pledge("stdio accept rpath proc exec", nullptr) < 0) {