HTTPRouter for CocoaHTTPServer

HTTPRouter.h

//
//  HTTPRouter.h
//  DynamicServer
//
//  Created by Zachry Thayer on 5/9/12.
//  Copyright (c) 2012 Zachry Thayer. All rights reserved.
//

#import "HTTPConnection.h"
#import "HTTPMessage.h"

@interface HTTPMessage (HTTPRouterMessage)

@property (nonatomic, copy) NSMutableDictionary* params;

@end

typedef id (^HTTPRouterBlock)(HTTPMessage* message);

@interface HTTPRouter : HTTPConnection
// :var = keyed variable 

+ (void)handleRoute:(NSString*)route withBlock:(HTTPRouterBlock)routeBlock;
+ (void)handleRoute:(NSString*)route withRouter:(HTTPRouter*)router;

@end

HTTPRouter.m

//
//  HTTPRouter.m
//  CocoaHTTPServer
//
//  Created by Zachry Thayer on 5/9/12.
//  Copyright (c) 2012 Zachry Thayer. All rights reserved.
//

#import "HTTPRouter.h"

#import "HTTPDataResponse.h"
#import "HTTPLogging.h"

#import <objc/runtime.h>

// Patch HTTPMessage to have params for the query and route parameters
static char * const HTTPRouterMessageKey = "HTTPRouterMessageKey";

@implementation HTTPMessage (HTTPRouterMessage)

- (void)setParams:(NSMutableDictionary *)newParams
{
	objc_setAssociatedObject(self, HTTPRouterMessageKey, newParams, OBJC_ASSOCIATION_COPY);
}

- (NSMutableDictionary*)params
{
	return objc_getAssociatedObject(self, HTTPRouterMessageKey);
}

@end

//Eeek! Globals!
NSMutableDictionary* HTTPRouterRoutes;
//BOOL HTTPRouterInitialized = NO;

@interface HTTPRouter ()

//Magic alias!
@property (nonatomic, strong)NSMutableDictionary* routes;

//Helpers
+ (void)prepareRoute:(NSString*)route;

- (HTTPDataResponse*)processResponse:(id)response;

@end

@implementation HTTPRouter

@synthesize routes;

#pragma mark method overides

- (NSObject<HTTPResponse> *)httpResponseForMethod:(NSString *)method URI:(NSString *)path
{
    
    // Find best matched route to request
    
    NSString* basePath = [[path componentsSeparatedByString:@"?"] objectAtIndex:0];
    
    //NSLog(@"Searching for path match to %@", basePath);
    
    for (NSString* key in self.routes)
    {
        NSString* predicatePath = [key stringByAppendingString:@".predicate"];
        NSPredicate *uriMatcher = [NSPredicate predicateWithFormat:[self.routes valueForKeyPath:predicatePath]];
        
        BOOL uriMatch = [uriMatcher evaluateWithObject:basePath];
        
        if (uriMatch) // Handle Match
        {
           // NSLog(@"Matched URI %@ with route %@", basePath, key); 
            NSString* blockPath = [key stringByAppendingString:@".block"];
            HTTPRouterBlock block = [self.routes valueForKeyPath:blockPath];
            
            request.params = [self parseRouteParams:key withURI:basePath];
            
            id response = block(request);
            
            //NSLog(@"Response:%@", response);
            
            return [self processResponse:response];
            
        }

    }
    
	
	// Default response
	return [super httpResponseForMethod:method URI:path];
}

- (NSMutableDictionary *)parseRouteParams:(NSString*)route withURI:(NSString*)path
{
    NSMutableDictionary* paramDictionary = [NSMutableDictionary dictionaryWithDictionary:[self parseGetParams]];
   
    NSMutableArray* components = [NSMutableArray arrayWithArray:[[path substringFromIndex:1] componentsSeparatedByString:@"/"]];

    NSMutableDictionary* routeDictionary = [self.routes valueForKey:route];
    NSDictionary* paramIndices = [routeDictionary valueForKey:@"paramIndices"];
    
    NSArray *keys = [self.routes keysSortedByValueUsingComparator:^(id obj1, id obj2) {
        int n1 = [[(NSDictionary *)obj1 valueForKey:@"specifity"] intValue];
        int n2 = [[(NSDictionary *)obj2 valueForKey:@"specifity"] intValue];

        if (n1 == n2) {
            return NSOrderedSame;
        }
        else if (n1 < n2) {
            return NSOrderedAscending;
        }
        else {
            return NSOrderedDescending;
        }
    }];

    for (NSString* key in keys)
    {
        NSString* value = [components objectAtIndex:[[paramIndices valueForKey:key] integerValue]];
        [paramDictionary setValue:value forKey:key];
    }
    
    return paramDictionary;
}

#pragma mark route management

+ (void)handleRoute:(NSString*)route withBlock:(HTTPRouterBlock)routeBlock
{
    if (!HTTPRouterRoutes)
    {
        HTTPRouterRoutes = [NSMutableDictionary dictionary];
    }
    
    //Add route
    NSMutableDictionary* routeDictionary = [NSMutableDictionary dictionary];
    //[routeDictionary setValue:(__bridge_transfer id)Block_copy((__bridge void *)routeBlock) forKey:@"block"];
    [routeDictionary setValue:[NSNumber numberWithInt:[HTTPRouterRoutes count]] forKey:@"specifity"];
    [routeDictionary setValue:[routeBlock copy] forKey:@"block"];
    [HTTPRouterRoutes setValue:routeDictionary forKey:route];
    
    [self prepareRoute:route];

}

+ (void)handleRoute:(NSString*)route withRouter:(HTTPRouter*)router
{
    if (!HTTPRouterRoutes)
    {
        HTTPRouterRoutes = [NSMutableDictionary dictionary];
    }
    
    //Add route 
    NSMutableDictionary* routeDictionary = [NSMutableDictionary dictionary];
    [routeDictionary setValue:[NSNumber numberWithInt:[HTTPRouterRoutes count]] forKey:@"specifity"];
    [routeDictionary setValue:router forKey:@"router"];    
    [HTTPRouterRoutes setValue:routeDictionary forKey:route];

    [self prepareRoute:route];
}


#pragma mark Accessor

- (NSMutableDictionary*)routes
{
    if (!HTTPRouterRoutes)
    {
        HTTPRouterRoutes = [NSMutableDictionary dictionary];
    }
    return HTTPRouterRoutes;
}

#pragma mark Helpers

+ (void)prepareRoute:(NSString*)route
{
    
    NSMutableDictionary* routeDictionary = [HTTPRouterRoutes valueForKey:route];
    
    NSMutableArray* components = [NSMutableArray arrayWithArray:[route componentsSeparatedByString:@"/"]];
    
    NSMutableString *regex = [NSMutableString stringWithFormat:@""];
    
    NSInteger index = 0;
    for (NSString *component in components) 
    {
        if ([component characterAtIndex:0] == ':')//Found parameter
        {
            //Prepare components to become a regex string
            //[components replaceObjectAtIndex:index withObject:@".*?\/"];
            [regex appendFormat:@".*\/?"];
            
            //Get parameter dictionary or create and add
            NSMutableDictionary* parameters = [routeDictionary valueForKey:@"paramIndices"];
            if (!parameters)
            {
                parameters = [NSMutableDictionary dictionary];
                [routeDictionary setValue:parameters forKey:@"paramIndices"];
            }
            
            //Insert the route component index for later easy fetching
            NSNumber* paramIndex = [NSNumber numberWithInteger:index];
            NSString* paramKey = [component substringFromIndex:1];//Skip ':'
            
            [parameters setValue:paramIndex forKey:paramKey];
        }
        else
        {   
            [regex appendFormat:@"\/%@", component];
        }
        
        index++;
    }
    
    //NSLog(@"Predicate Regex: %@", regex);
    
    NSString* predicate = [NSString stringWithFormat:@"SELF MATCHES '%@\/?'", regex];//skip first /
    
    [routeDictionary setValue:predicate forKey:@"predicate"];

}

- (HTTPDataResponse*)processResponse:(id)response
{
    HTTPDataResponse *dataResponse = nil;
    
    if ([response isKindOfClass:[NSString class]])
    {
        dataResponse = [[HTTPDataResponse alloc] initWithData:[response dataUsingEncoding:NSUTF8StringEncoding]];
    }
    
    if ([response isKindOfClass:[NSData class]])
    {
        dataResponse = [[HTTPDataResponse alloc] initWithData:response];
    }
    
    if ([response isKindOfClass:[NSDictionary class]] || [response isKindOfClass:[NSArray class]])
    {
        dataResponse = [[HTTPDataResponse alloc] initWithData:[NSJSONSerialization dataWithJSONObject:response options:0 error:nil]];
    }
    
    return dataResponse;
}

@end