I am trying to re-implement ASP.NET MVC routing rules in C ++ for my own MVC application.
Currently, the code takes at least O (N) and in the best case, if access to the controller / action inside unordered_map is not O (1) .
I would like my code to prefer a route with a controller that is already in the URI, for example if the current URI is ' projects / 2 / show ' , and I have ' [Controller] / [Action] / [ID] / , '[Controller] / [ID] / [Action] /' , 'projects / [ID] / [Action] /' and 'projects / [ID] / show' I prefer the last route to be checked for the first. My question is: how can this be done?
At the moment, he will go through all the routes and try to match it.
I tried to document the code as much as possible, but let me know if something is unclear.
My current code is as follows:
// handlePathChange() is called whenever the URI changes void MVCApplication::handlePathChange() { // Right now I'm iterating a list (O(N) runtime) RoutesListType::iterator iter = routes.begin(); // If there are no routes then something is wrong if ( iter == routes.end() ) { log("Error") << "No routes found"; return; } bool pageFound = false; // iterate until a route matches or until the routes end while ( iter != routes.end() ) { if ( matches(*iter) ) { pageFound = true; break; } iter++; } // If a page is not found then log it if (!pageFound) log("Error") << "404, page at url " << internalPath() << " not found"; } bool MVCApplication::matches(Route &r) { log("Notice") << "Matching route pattern " << r.getPattern() + " to url " << internalPath(); // gets the URI const string url = internalPath(); char_separator<char> urlSep("/"); char_separator<char> patternSep("[]/"); boost::tokenizer<boost::char_separator<char> > patternTokens(r.getPattern(), patternSep); tokenizer<char_separator<char> > urlTokens(url, urlSep); int pos = 1; bool actionFound = false; Route::RouteDefaultsType &defaults = r.getDefaults(); // unordered_set<string, string> ControllerMapType &controllers = getControllers(); // unordered_set<string, shared_ptr<Controller> > ControllerType currentController; // shared_ptr<Controller> Controller::ActionType action; // boost::function that returns a view for (tokenizer<char_separator<char> >::iterator pattern_iter = patternTokens.begin(), url_iter = urlTokens.begin(); pattern_iter != patternTokens.end(); ++pattern_iter, pos++) { if ( url_iter == urlTokens.end() ) // If the number of URI tokens is lower then route tokens seek default values { if ( *pattern_iter == "Controller" || pos == 1) // Map controller to default { if ( defaults.find(*pattern_iter) != defaults.end() ) currentController = controllers[defaults[*pattern_iter]]; else { log("Error") << "No default controller found"; return false; } } else if ( *pattern_iter == "Action" ) // Map action to default { Route::RouteDefaultsType::const_iterator iter = defaults.find(*pattern_iter); if ( iter != defaults.end() ) { if ( currentController->getActions().find(iter->second) != currentController->getActions().end() ) { action = currentController->getActions()[iter->second]; actionFound = true; } } } // Checks whether the hard-coded value in the route is an action or a parameter else { Route::RouteDefaultsType::const_iterator iter = defaults.find(*pattern_iter); // Search for a static action eg. /[Controller]/edit/ if ( currentController->getActions().find(iter->second) != currentController->getActions().end() ) { action = currentController->getActions()[iter->second]; actionFound = true; } else // Maps parameters to defualt values { boost::unordered_map<string, string>::const_iterator iter = defaults.find(*pattern_iter); if ( iter != defaults.end() ) currentController->addParameter(*pattern_iter, iter->second); } } } else // Match non-default values { if ( *pattern_iter == "Controller" || pos == 1) // Match controller { if ( getControllers().find(*url_iter) != getControllers().end() ) currentController = controllers[*url_iter]; else return false; } else if ( *pattern_iter == "Action" ) // Match action { if ( currentController->getActions().find(*url_iter) != currentController->getActions().end() ) { action = currentController->getActions()[*url_iter]; actionFound = true; } } // Checks whether the hard-coded value in the route is an action or a parameter else { if ( currentController->getActions().find(*url_iter) != currentController->getActions().end() ) { action = currentController->getActions()[*url_iter]; actionFound = true; } else // If not, as a parameter currentController->addParameter(*pattern_iter, *url_iter); } ++url_iter; } } // If controller action found show view if ( actionFound ) { if ( currentView ) root()->removeWidget(currentView); currentView = action(); // Perform action root()->addWidget(currentView); } else { log("Error") << "No action found"; return false; } return true; }
The algorithm is as follows:
foreach route: if the route matches then: break. if number of url tokens < number of route pattern tokens then: if pattern token == "Controller" or it is the first token then: if the default controller exists then: assign it as the current controller. else: return false else if pattern token == "Action" then: if the default action exists in the current controller then: assign it as the current action. set actionFound to true. else: if the hard-coded action in the routes exists in the current controller then: assign it as the current action. set actionFound to true. else: if a default value for this parameter exists: add a parameter with a default value and route token as name to the current controller. else: if pattern token == "Controller" or it is the first token then: if the url token matches a controller name then: assign it as the current controller. else: return false else if pattern token == "Action" then: if the url token matches an action name inside the current controller then: assign it as the current action. set actionFound to true. else: if the hard-coded action in the uri token exists in the current controller then: assign it as the current action. set actionFound to true. else: add a parameter with a uri token as value and route token as name to the current controller. if actionFound == true then: perform controller action. render view. return actionFound
I would really like any suggestions for improvement, including in the formatting and structure of the code, but mainly in the efficiency of execution.
source share