RestKit/Code/Support/RKPathMatcher.m

//
//  RKPathMatcher.m
//  RestKit
//
//  Created by Greg Combs on 9/2/11.
//  Copyright (c) 2009-2012 RestKit. All rights reserved.
//
//  Licensed under the Apache License, Version 2.0 (the "License");
//  you may not use this file except in compliance with the License.
//  You may obtain a copy of the License at
//
//  http://www.apache.org/licenses/LICENSE-2.0
//
//  Unless required by applicable law or agreed to in writing, software
//  distributed under the License is distributed on an "AS IS" BASIS,
//  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
//  See the License for the specific language governing permissions and
//  limitations under the License.
//

#import "RKPathMatcher.h"
#import "SOCKit.h"
#import "RKLog.h"
#import "RKDictionaryUtilities.h"

static NSString *RKEncodeURLString(NSString *unencodedString);
static NSDictionary *RKQueryParametersFromStringWithEncoding(NSString *string, NSStringEncoding stringEncoding);

// NSString's stringByAddingPercentEscapes doesn't do a complete job (it ignores "/?&", among others)
static NSString *RKEncodeURLString(NSString *unencodedString)
{
    NSString *encodedString = (NSString *)CFBridgingRelease(CFURLCreateStringByAddingPercentEscapes(
                                                                                  NULL,
                                                                                  (__bridge CFStringRef)unencodedString,
                                                                                  NULL,
                                                                                  (CFStringRef)@"!*'();:@&=+$,/?%#[]",
                                                                                  kCFStringEncodingUTF8));
    return encodedString;
}

static NSDictionary *RKQueryParametersFromStringWithEncoding(NSString *string, NSStringEncoding encoding)
{
    BOOL shouldUseArrays = NO; // NOTE: This flag causes all parameters to be boxed into arrays. Unsure of utility.
    NSRange chopRange = [string rangeOfString:@"?"];
    if (chopRange.length > 0) {
        chopRange.location += 1; // we want inclusive chopping up *through *"?"
        if (chopRange.location < [string length]) string = [string substringFromIndex:chopRange.location];
    }
    NSCharacterSet *delimiterSet = [NSCharacterSet characterSetWithCharactersInString:@"&;"];
    NSMutableDictionary *pairs = [NSMutableDictionary dictionary];
    NSScanner *scanner = [[NSScanner alloc] initWithString:string];
    while (![scanner isAtEnd]) {
        NSString *pairString = nil;
        [scanner scanUpToCharactersFromSet:delimiterSet intoString:&pairString];
        [scanner scanCharactersFromSet:delimiterSet intoString:NULL];
        NSArray *kvPair = [pairString componentsSeparatedByString:@"="];
        
        if (!shouldUseArrays) {
            if (kvPair.count == 2) {
                NSString *key = [[kvPair objectAtIndex:0]
                                 stringByReplacingPercentEscapesUsingEncoding:encoding];
                NSString *value = [[kvPair objectAtIndex:1]
                                   stringByReplacingPercentEscapesUsingEncoding:encoding];
                [pairs setObject:value forKey:key];
            }
        }
        else {
            if (kvPair.count == 1 || kvPair.count == 2) {
                NSString *key = [[kvPair objectAtIndex:0]
                                 stringByReplacingPercentEscapesUsingEncoding:encoding];
                NSMutableArray *values = [pairs objectForKey:key];
                if (nil == values) {
                    values = [NSMutableArray array];
                    [pairs setObject:values forKey:key];
                }
                if (kvPair.count == 1) {
                    [values addObject:[NSNull null]];
                    
                } else if (kvPair.count == 2) {
                    NSString *value = [[kvPair objectAtIndex:1]
                                       stringByReplacingPercentEscapesUsingEncoding:encoding];
                    [values addObject:value];
                }
            }
        }
    }
    return [NSDictionary dictionaryWithDictionary:pairs];
}

@interface RKPathMatcher ()
@property (nonatomic, strong) SOCPattern *socPattern;
@property (nonatomic, copy) NSString *sourcePath;
@property (nonatomic, copy) NSString *rootPath;
@property (copy, readwrite) NSDictionary *queryParameters;
@end

@implementation RKPathMatcher

- (id)copyWithZone:(NSZone *)zone
{
    RKPathMatcher *copy = [[[self class] allocWithZone:zone] init];
    copy.socPattern = self.socPattern;
    copy.sourcePath = self.sourcePath;
    copy.rootPath = self.rootPath;
    copy.queryParameters = self.queryParameters;

    return copy;
}


+ (RKPathMatcher *)matcherWithPattern:(NSString *)patternString
{
    NSAssert(patternString != NULL, @"Pattern string must not be empty in order to perform pattern matching.");
    RKPathMatcher *matcher = [[RKPathMatcher alloc] init];
    matcher.socPattern = [SOCPattern patternWithString:patternString];
    return matcher;
}

+ (RKPathMatcher *)matcherWithPath:(NSString *)pathString
{
    RKPathMatcher *matcher = [[RKPathMatcher alloc] init];
    matcher.sourcePath = pathString;
    matcher.rootPath = pathString;
    return matcher;
}

- (BOOL)matches
{
    NSAssert((self.socPattern != NULL && self.rootPath != NULL), @"Matcher is insufficiently configured.  Before attempting pattern matching, you must provide a path string and a pattern to match it against.");
    return [self.socPattern stringMatches:self.rootPath];
}

- (BOOL)bifurcateSourcePathFromQueryParameters
{
    NSArray *components = [self.sourcePath componentsSeparatedByString:@"?"];
    if ([components count] > 1) {
        self.rootPath = [components objectAtIndex:0];
        self.queryParameters = RKQueryParametersFromStringWithEncoding([components objectAtIndex:1], NSUTF8StringEncoding);
        return YES;
    }
    return NO;
}

- (BOOL)itMatchesAndHasParsedArguments:(NSDictionary **)arguments tokenizeQueryStrings:(BOOL)shouldTokenize
{
    NSAssert(self.socPattern != NULL, @"Matcher has no established pattern.  Instantiate it using matcherWithPattern: before attempting a pattern match.");
    NSMutableDictionary *argumentsCollection = [NSMutableDictionary dictionary];
    if ([self bifurcateSourcePathFromQueryParameters]) {
        if (shouldTokenize) {
            [argumentsCollection addEntriesFromDictionary:self.queryParameters];
        }
    }
    if (![self matches])
        return NO;
    if (!arguments) {
        return YES;
    }
    NSDictionary *extracted = [self.socPattern parameterDictionaryFromSourceString:self.rootPath];
    if (extracted)
        [argumentsCollection addEntriesFromDictionary:RKDictionaryByReplacingPercentEscapesInEntriesFromDictionary(extracted)];
    *arguments = argumentsCollection;
    return YES;
}

- (BOOL)matchesPattern:(NSString *)patternString tokenizeQueryStrings:(BOOL)shouldTokenize parsedArguments:(NSDictionary **)arguments
{
    NSAssert(patternString != NULL, @"Pattern string must not be empty in order to perform patterm matching.");
    self.socPattern = [SOCPattern patternWithString:patternString];
    return [self itMatchesAndHasParsedArguments:arguments tokenizeQueryStrings:shouldTokenize];
}

- (BOOL)matchesPath:(NSString *)sourceString tokenizeQueryStrings:(BOOL)shouldTokenize parsedArguments:(NSDictionary **)arguments
{
    self.sourcePath = sourceString;
    self.rootPath = sourceString;
    return [self itMatchesAndHasParsedArguments:arguments tokenizeQueryStrings:shouldTokenize];
}

- (NSString *)pathFromObject:(id)object
{
    return [self pathFromObject:object addingEscapes:YES];
}

- (NSString *)pathFromObject:(id)object addingEscapes:(BOOL)addEscapes
{
    NSAssert(self.socPattern != NULL, @"Matcher has no established pattern.  Instantiate it using matcherWithPattern: before calling pathFromObject:");
    NSAssert(object != NULL, @"Object provided is invalid; cannot create a path from a NULL object");
    NSString *(^encoderBlock)(NSString *interpolatedString) = nil;
    if (addEscapes)
        encoderBlock = ^NSString *(NSString *interpolatedString) {
            return RKEncodeURLString(interpolatedString);
        };
    NSString *path = [self.socPattern stringFromObject:object withBlock:encoderBlock];
    return path;
}

@end