ARService+Private.m

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// ActiveResourceKit ARService+Private.m
//
// Copyright © 2011, 2012, Roy Ratcliffe, Pioneering Software, United Kingdom
//
// Permission is hereby granted, free of charge, to any person obtaining a copy
// of this software and associated documentation files (the "Software"), to deal
// in the Software without restriction, including without limitation the rights
// to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
// copies of the Software, and to permit persons to whom the Software is
// furnished to do so, subject to the following conditions:
//
//  The above copyright notice and this permission notice shall be included in
//  all copies or substantial portions of the Software.
//
// THE SOFTWARE IS PROVIDED "AS IS," WITHOUT WARRANTY OF ANY KIND, EITHER
// EXPRESSED OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
// MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NON-INFRINGEMENT. IN NO
// EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES
// OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE,
// ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
// DEALINGS IN THE SOFTWARE.
//
//------------------------------------------------------------------------------

#import "ARService+Private.h"
#import "ARConnection.h"

#import <ActiveResourceKit/ActiveResourceKit.h>
#import <ActiveModelKit/ActiveModelKit.h>
#import <ActiveSupportKit/ActiveSupportKit.h>

NSString *const ARFromKey = @"from";
NSString *const ARParamsKey = @"params";

NSString *ARQueryStringForOptions(NSDictionary *options)
{
    return options == nil || [options count] == 0 ? @"" : [NSString stringWithFormat:@"?%@", [options toQueryWithNamespace:nil]];
}

@implementation ARService(Private)

- (id<ARFormat>)defaultFormat
{
    return [ARJSONFormat JSONFormat];
}

- (NSString *)defaultElementName
{
    return [[[AMName alloc] initWithClass:[self class]] element];
}

- (NSString *)defaultCollectionName
{
    return [[ASInflector defaultInflector] pluralize:[self elementNameLazily]];
}

- (NSString *)defaultPrimaryKey
{
    return @"id";
}

- (NSString *)defaultPrefixSource
{
    return [[self site] path];
}

- (void)findEveryWithOptions:(NSDictionary *)options completionHandler:(void (^)(ARHTTPResponse *response, NSArray *resources, NSError *error))completionHandler
{
    NSString *path;
    NSDictionary *prefixOptions;
    NSString *from = [options objectForKey:ARFromKey];
    if (from && [from isKindOfClass:[NSString class]])
    {
        prefixOptions = nil;
        path = [NSString stringWithFormat:@"%@%@", from, ARQueryStringForOptions([options objectForKey:ARParamsKey])];
    }
    else
    {
        NSDictionary *queryOptions = nil;
        [self splitOptions:options prefixOptions:&prefixOptions queryOptions:&queryOptions];
        path = [self collectionPathWithPrefixOptions:prefixOptions queryOptions:queryOptions];
    }
    [self get:path completionHandler:^(ARHTTPResponse *response, id object, NSError *error) {
        if ([object isKindOfClass:[NSArray class]])
        {
            completionHandler(response, [self instantiateCollection:object prefixOptions:prefixOptions], nil);
        }
        else
        {
            completionHandler(response, nil, [NSError errorWithDomain:ARErrorDomain code:ARUnsupportedRootObjectTypeError userInfo:nil]);
        }
    }];
}

- (NSArray *)instantiateCollection:(NSArray *)collection prefixOptions:(NSDictionary *)prefixOptions
{
    NSMutableArray *resources = [NSMutableArray array];
    for (NSDictionary *attributes in collection)
    {
        [resources addObject:[self instantiateRecordWithAttributes:attributes prefixOptions:prefixOptions]];
    }
    return [resources copy];
}

- (ARResource *)instantiateRecordWithAttributes:(NSDictionary *)attributes prefixOptions:(NSDictionary *)prefixOptions
{
    Class aClass = NSClassFromString(ASInflectorCamelize([self elementNameLazily], YES));
    if (aClass == nil || ![aClass isSubclassOfClass:[ARResource class]])
    {
        aClass = [ARResource class];
    }
    ARResource *resource = [[aClass alloc] initWithService:self attributes:attributes persisted:YES];
    [resource setPrefixOptions:prefixOptions];
    return resource;
}

- (NSSet *)prefixParameters
{
    NSMutableSet *parameters = [NSMutableSet set];
    NSString *prefixSource = [self prefixSourceLazily];
    for (NSTextCheckingResult *result in [[NSRegularExpression regularExpressionWithPattern:@":\\w+" options:0 error:NULL] matchesInString:prefixSource options:0 range:NSMakeRange(0, [prefixSource length])])
    {
        [parameters addObject:[[prefixSource substringWithRange:[result range]] substringFromIndex:1]];
    }
    return [parameters copy];
}

- (void)splitOptions:(NSDictionary *)options prefixOptions:(NSDictionary **)outPrefixOptions queryOptions:(NSDictionary **)outQueryOptions
{
    NSSet *prefixParameters = [self prefixParameters];
    NSMutableDictionary *prefixOptions = [NSMutableDictionary dictionary];
    NSMutableDictionary *queryOptions = [NSMutableDictionary dictionary];
    [options enumerateKeysAndObjectsUsingBlock:^(id key, id obj, BOOL *stop) {
        [[prefixParameters member:key] != nil ? prefixOptions : queryOptions setObject:obj forKey:key];
    }];
    if (outPrefixOptions)
    {
        *outPrefixOptions = [prefixOptions copy];
    }
    if (outQueryOptions)
    {
        *outQueryOptions = [queryOptions copy];
    }
}

//------------------------------------------------------------------------------
#pragma mark                                                       HTTP Requests
//------------------------------------------------------------------------------

// Under Rails, the HTTP request methods belong to a separate connection class,
// ActiveResource::Connection. That class acts as a shim in-between active
// resources and the Net::HTTP library, handling authentication and encryption
// if the connection requires such features. The Objective-C implementation
// obviates the connection class by delegating to the underlying Apple
// NSURLConnection implementation for the handling of authentication and
// encryption.

- (void)get:(NSString *)path completionHandler:(ARServiceRequestCompletionHandler)completionHandler
{
    [self requestHTTPMethod:ARHTTPGetMethod path:path body:nil completionHandler:completionHandler];
}

- (void)delete:(NSString *)path completionHandler:(ARServiceRequestCompletionHandler)completionHandler
{
    [self requestHTTPMethod:ARHTTPDeleteMethod path:path body:nil completionHandler:completionHandler];
}

- (void)put:(NSString *)path body:(NSData *)data completionHandler:(ARServiceRequestCompletionHandler)completionHandler
{
    [self requestHTTPMethod:ARHTTPPutMethod path:path body:data completionHandler:completionHandler];
}

- (void)post:(NSString *)path body:(NSData *)data completionHandler:(ARServiceRequestCompletionHandler)completionHandler
{
    [self requestHTTPMethod:ARHTTPPostMethod path:path body:data completionHandler:completionHandler];
}

- (void)head:(NSString *)path completionHandler:(ARServiceRequestCompletionHandler)completionHandler
{
    [self requestHTTPMethod:ARHTTPHeadMethod path:path body:nil completionHandler:completionHandler];
}

- (void)requestHTTPMethod:(NSString *)HTTPMethod path:(NSString *)path body:(NSData *)data completionHandler:(ARServiceRequestCompletionHandler)completionHandler
{
    ARConnection *connection = [self connectionLazily];
    NSMutableURLRequest *request = [connection requestForHTTPMethod:HTTPMethod path:path headers:[[self headers] copy]];
    if (data)
    {
        [request setHTTPBody:data];
    }
    [connection sendRequest:request completionHandler:[self decodeHandlerWithCompletionHandler:completionHandler]];
}

- (ARConnectionCompletionHandler)decodeHandlerWithCompletionHandler:(ARServiceRequestCompletionHandler)completionHandler
{
    // This response handler exists for two main purposes: (1) to cast the
    // generalised URL response to a protocol-specific HTTP response; (2) to
    // decode the body. Purpose number two presumes that all responses arriving
    // here require format-specific decoding. If this is not true, do not use
    // this handler. Instead, roll your own.
    //
    // Sends -copy to the block thereby transferring the block from the local
    // stack to the heap. Copy for use after the destruction of this
    // scope. Compiling for iOS raises a warning unless you copy the block, but
    // not so for OS X.
    return // What if the response body proves empty? This happens for// responses to DELETE requests. Never attempt to decode a// zero-length data body. Zero-length data is valid for some// operations. It does not necessarily signal an// error. Instead, pass the result up through to the// higher-level software layers as success. Let higher-level// software make a decision about validity.//// Rails answers a single space for DELETE responses, in// fact for all responses where your action controller uses// the "head" method. Explicitly, the action controller head// method assigns a single space for the response// body. Unfortunately, this fails to successfully// decode. White space does not correctly decode a JSON// object. Instead it produces an error. Work around is// issue by trimming white space.// decoding error// response error// connection error// type error[^(ARHTTPResponse *response, NSError *error) {
        if (response)
        {
            if ([response body])
            {
                error = [ARConnection errorForResponse:response];
                if (error == nil)
                {
                    
                    
                    
                    
                    
                    
                    
                    
                    
                    
                    
                    
                    
                    
                    
                    
                    NSData *data = [response body];
                    NSString *string = [[NSString alloc] initWithData:data encoding:NSUTF8StringEncoding];
                    if (string)
                    {
                        data = [[string stringByTrimmingCharactersInSet:[NSCharacterSet whitespaceCharacterSet]] dataUsingEncoding:NSUTF8StringEncoding];
                    }
                    id object = data && [data length] ? [[self formatLazily] decode:data error:&error] : nil;
                    if (error == nil)
                    {
                        completionHandler(response, object, nil);
                    }
                    else
                    {
                        
                        completionHandler(response, nil, error);
                    }
                }
                else
                {
                    
                    completionHandler(response, nil, error);
                }
            }
            else
            {
                
                completionHandler(response, nil, error);
            }
        }
        else
        {
            
            completionHandler(nil, nil, error ? error : [NSError errorWithDomain:ARErrorDomain code:ARResponseIsNotHTTPError userInfo:nil]);
        }
    } copy];
}

@end