MGJRouter源碼解析及使用方法

MGJRouter源碼解析

MGJRouter是實現iOS組件間交互的工具之一，路由的使用降低了不同模塊之間的耦合度，提高代碼的復用率以及不同模塊間重組的靈活度，下面我就針對MGJRouter說一下自己的理解：

注冊

routes主要用於存儲已經注冊過的路徑及block

@property (nonatomic) NSMutableDictionary *routes;

下面三個方法是注冊時對URL進行遞歸遍歷以及對block進行存儲

- (void)addURLPattern:(NSString *)URLPattern andHandler:(MGJRouterHandler)handler
{
    //解析當前 URL 並轉化出字典存貯在self.routes中
    NSMutableDictionary *subRoutes = [self addURLPattern:URLPattern];
    //將block存入到字典中
    if (handler && subRoutes) {
        subRoutes[@"_"] = [handler copy];
    }
}

- (void)addURLPattern:(NSString *)URLPattern andObjectHandler:(MGJRouterObjectHandler)handler
{
    NSMutableDictionary *subRoutes = [self addURLPattern:URLPattern];
    if (handler && subRoutes) {
        subRoutes[@"_"] = [handler copy];
    }
}

- (NSMutableDictionary *)addURLPattern:(NSString *)URLPattern
{
    //拆分當前URL
    NSArray *pathComponents = [self pathComponentsFromURL:URLPattern];

    NSMutableDictionary* subRoutes = self.routes;
    
    //進行輪循依次將component按照字典存入
    for (NSString* pathComponent in pathComponents) {
        //由於按照順序存儲所以先存入的生效，后面的將無法存入
        if (![subRoutes objectForKey:pathComponent]) {
            //依次生成字典存入上一層字典
            subRoutes[pathComponent] = [[NSMutableDictionary alloc] init];
        }
        //依次將最里面的字典賦值給subRoutes
        subRoutes = subRoutes[pathComponent];
    }
    //將最里層的字典返回
    return subRoutes;
}

最終存儲數據的格式如下，調用時會對其中的字典進行遞歸查找

{
    LWT =     {
        Home =         {
            OtherViewController =             {
                "_" = "<__NSGlobalBlock__: 0x10c5b0168>";
            };
            SecondViewController =             {
                "_" = "<__NSGlobalBlock__: 0x10c5b0148>";
            };
        };
    };
}

調用

調用時會將路徑進行分解遞歸查找到對應的block，並將傳遞進來的參數進行存儲

+ (void)openURL:(NSString *)URL
{
    [self openURL:URL completion:nil];
}

+ (void)openURL:(NSString *)URL completion:(void (^)(id result))completion
{
    [self openURL:URL withUserInfo:nil completion:completion];
}

+ (void)openURL:(NSString *)URL withUserInfo:(NSDictionary *)userInfo completion:(void (^)(id result))completion
{
    URL = [URL stringByAddingPercentEscapesUsingEncoding:NSUTF8StringEncoding];
    NSMutableDictionary *parameters = [[self sharedInstance] extractParametersFromURL:URL matchExactly:NO];
    
    //遍歷字典
    [parameters enumerateKeysAndObjectsUsingBlock:^(id key, NSString *obj, BOOL *stop) {
        if ([obj isKindOfClass:[NSString class]]) {
            //讀出
            parameters[key] = [obj stringByReplacingPercentEscapesUsingEncoding:NSUTF8StringEncoding];
        }
    }];
    
    if (parameters) {
        //取出block並根據請求進行回調
        MGJRouterHandler handler = parameters[@"block"];
        
        //將方法中的參數和block保存下來以便后期使用
        if (completion) {
            parameters[MGJRouterParameterCompletion] = completion;
        }
        if (userInfo) {
            parameters[MGJRouterParameterUserInfo] = userInfo;
        }
        if (handler) {
            //刪除注冊時的block並發起回調
            [parameters removeObjectForKey:@"block"];
            NSLog(@"開始調用Block");
            handler(parameters);
        }
    }
}

路由注銷

- (void)removeURLPattern:(NSString *)URLPattern
{
    //URL分解
    NSMutableArray *pathComponents = [NSMutableArray arrayWithArray:[self pathComponentsFromURL:URLPattern]];
    
    // 只刪除該 pattern 的最后一級
    if (pathComponents.count >= 1) {
        // 假如 URLPattern 為 a/b/c, components 就是 @"a.b.c" 正好可以作為 KVC 的 key
        //獲取數組拼接的key
        NSString *components = [pathComponents componentsJoinedByString:@"."];
        NSMutableDictionary *route = [self.routes valueForKeyPath:components];
        
        if (route.count >= 1) {
            //刪除最后一個參數
            NSString *lastComponent = [pathComponents lastObject];
            [pathComponents removeLastObject];
            
            // 有可能是根 key，這樣就是 self.routes 了
            route = self.routes;
            //獲取字典層級的倒數第二層字典並刪除
            if (pathComponents.count) {
                NSString *componentsWithoutLast = [pathComponents componentsJoinedByString:@"."];
                route = [self.routes valueForKeyPath:componentsWithoutLast];
            }
            [route removeObjectForKey:lastComponent];
        }
    }
}

路由判斷

即根據路徑獲取相應的block，如果沒有查找到則返回nil

//根據路徑取出block
- (NSMutableDictionary *)extractParametersFromURL:(NSString *)url matchExactly:(BOOL)exactly
{
    NSMutableDictionary* parameters = [NSMutableDictionary dictionary];
    
    parameters[MGJRouterParameterURL] = url;
    
    //獲取路由中存儲的路由集合
    NSMutableDictionary* subRoutes = self.routes;
    //傳入地址的組件
    NSArray* pathComponents = [self pathComponentsFromURL:url];
    
    BOOL found = NO;
    // borrowed from HHRouter(https://github.com/Huohua/HHRouter)
    //遍歷傳入URL組件
    for (NSString* pathComponent in pathComponents) {
        
        // 對 key 進行排序，這樣可以把 ~ 放到最后
        NSArray *subRoutesKeys =[subRoutes.allKeys sortedArrayUsingComparator:^NSComparisonResult(NSString *obj1, NSString *obj2) {
            return [obj1 compare:obj2];
        }];
        //遍歷全部路由key值進行比對查找
        for (NSString* key in subRoutesKeys) {
            
            if ([key isEqualToString:pathComponent] || [key isEqualToString:MGJ_ROUTER_WILDCARD_CHARACTER]) {
                found = YES;
                //查找到后取出子字典繼續遍歷
                subRoutes = subRoutes[key];
                break;
            } else if ([key hasPrefix:@":"]) {  //判斷字符串是否以:為前綴
                found = YES;
                subRoutes = subRoutes[key];
                NSString *newKey = [key substringFromIndex:1];
                NSString *newPathComponent = pathComponent;
                // 再做一下特殊處理，比如 :id.html -> :id
                if ([self.class checkIfContainsSpecialCharacter:key]) {
                    NSCharacterSet *specialCharacterSet = [NSCharacterSet characterSetWithCharactersInString:specialCharacters];
                    NSRange range = [key rangeOfCharacterFromSet:specialCharacterSet];
                    if (range.location != NSNotFound) {
                        // 把 pathComponent 后面的部分也去掉
                        newKey = [newKey substringToIndex:range.location - 1];
                        NSString *suffixToStrip = [key substringFromIndex:range.location];
                        newPathComponent = [newPathComponent stringByReplacingOccurrencesOfString:suffixToStrip withString:@""];
                    }
                }
                parameters[newKey] = newPathComponent;
                break;
            } else if (exactly) {
                found = NO;
            }
        }
        
        // 如果沒有找到該 pathComponent 對應的 handler，則以上一層的 handler 作為 fallback
        if (!found && !subRoutes[@"_"]) {
            return nil;
        }
    }
    
    // Extract Params From Query.
    NSArray<NSURLQueryItem *> *queryItems = [[NSURLComponents alloc] initWithURL:[[NSURL alloc] initWithString:url] resolvingAgainstBaseURL:false].queryItems;
    
    for (NSURLQueryItem *item in queryItems) {
        parameters[item.name] = item.value;
    }
    //將block放入字典中返回
    if (subRoutes[@"_"]) {
        parameters[@"block"] = [subRoutes[@"_"] copy];
    }
    
    return parameters;
}

MGJRouter的使用

• 注冊

    //無參數的
    [MGJRouter registerURLPattern:[self appendAnimUrl:@"SecondViewController"] toHandler:^(NSDictionary *routerParameters) {
        NSLog(@"routerParameters[ViewController]:%@", routerParameters[@"ViewController"]); // halfrost
        UINavigationController *navigationVC = routerParameters[MGJRouterParameterUserInfo][@"navigationVC"];
        SecondController *vc = [[SecondController alloc] init];
        [navigationVC pushViewController:vc animated:YES];
    }];

    //有參數無回調
    [MGJRouter registerURLPattern:[self appendAnimUrl:@"OtherViewController"] toHandler:^(NSDictionary *routerParameters) {
        UINavigationController *navigationVC = routerParameters[MGJRouterParameterUserInfo][@"navigationVC"];
        NSString *labelText = routerParameters[MGJRouterParameterUserInfo][@"text"];
        OtherViewController *vc = [[OtherViewController alloc] init];
        vc.titleText = labelText;
        [navigationVC pushViewController:vc animated:YES];
    }];
    
    //有參數有回調
    [MGJRouter registerURLPattern:[self appendAnimUrl:@"ThridViewController"] toHandler:^(NSDictionary *routerParameters) {
        UINavigationController *navigationVC = routerParameters[MGJRouterParameterUserInfo][@"navigationVC"];
        void(^block)(NSString *) = routerParameters[MGJRouterParameterUserInfo][@"block"];
        ThridViewController *vc = [[ThridViewController alloc] init];
        vc.titleText = routerParameters[MGJRouterParameterUserInfo][@"text"];
        vc.backBlock = block;
        [navigationVC pushViewController:vc animated:YES];
    }];

• 調用

由於是通過路徑進行的查找相應的controller增加了大量的硬編碼，直接通過MGJrouter的方法調用無疑會增加pushController中代碼的復雜度，同時也提高了開發者之間溝通交流的成本，在這里通過對MGJrouter進行分類增加跳轉方法以便降低模塊間溝通的成本，同理注冊的時候也可以對其增加分類以防止單個文件過重，並且在此處可以增加參數判斷以防止傳參丟失等情況的出現

#define Home_base_Url @"LWT://Home/:name"

+ (void)pushSecondCtl:(UINavigationController *)nav
{
    [MGJRouter openURL:[MGJRouter generateURLWithPattern:Home_base_Url parameters:@[@"SecondViewController"]] withUserInfo:@{@"navigationVC":nav} completion:nil];
}

+ (void)pushOtherController:(UINavigationController *)nav title:(NSString *)titleText
{
    [MGJRouter openURL:[MGJRouter generateURLWithPattern:Home_base_Url parameters:@[@"OtherViewController"]]
    withUserInfo:@{@"navigationVC" : nav,
                   @"text": titleText,
                   }
      completion:nil];
}

+ (void)pushThridController:(UINavigationController *)nav title:(NSString *)titleText block:(void (^)(NSString * result))block
{
    [MGJRouter openURL:[MGJRouter generateURLWithPattern:Home_base_Url parameters:@[@"ThridViewController"]]
    withUserInfo:@{@"navigationVC" : nav,
                   @"text": titleText,
                   @"block":block
                   }
            completion:nil];
}

以上就是我對MGJrouter的理解及使用，如有不足歡迎補充