FatSecret Platform API

在现阶段饮食类的APP发展的非常迅猛，尤其在校园中，学生只需要凭借一个手机就能买到自己想要的食物，真正做到了足不出户。可是如果我们想独立完成一个app就需要有相应的数据支持，这里给大家介绍一个国外的开发API, FatSecret Platform API,这里面包含了许多的食物信息。我们根据这些信息，就能够请求我们的数据，进行独立的app开发。

1、api地址

http://platform.fatsecret.com/api/Default.aspx?screen=rapih

2、Authentication 认证

这里要注意， Authentication 是难点也是重点，下面我们一起研究研究怎么进行认证。

Api中提到，如果我们需要使用api必须首先注册为开发者，并且获取到 Consumer Key and Shared Secret ， 这两个东西。好既然这样我们就开始获取,按照网站注册后如会获取如下数据

有了这个东西我们就可以进行下一步了。继续浏览API的Authentication

看到这我们会发现想要请求api必须还得获取一个signature ,而且上面给我们提供了步骤。好那我们就接着往下看

Step 1. Creating a Signature Base String

意思就是说，我们需要将字段和方法按照顺序拼接出下面的形式，其中的转码我们用的是 RFC3986

Step 2. Calculating the Signature value (oauth_signature)

意思是说需要进一步 RFC2104 和RFC2045和RFC3986进行转码

Step 3. Sending the Request

好，看到这里大家肯定有些模糊，没关系，我们有代码帮助大家理解，上面的api步骤，我通过代码翻译如下

/**  *  <#Description#>  *  *  @param url      请求的地址  *  @param method      请求的方法  *  @param body     body数据  *  @param _oAuthConsumerKey 申请的key  *  @param _oAuthConsumerSecret  申请的Secret  *  @param _oAuthToken    暂时用不到  *  @param _oAuthTokenSecret 暂时用不到  *  *  @return <#return value description#>  */ NSString *OAuthorizationHeader(NSURL *url, NSString *method, NSData *body, NSString *_oAuthConsumerKey, NSString *_oAuthConsumerSecret, NSString *_oAuthToken, NSString *_oAuthTokenSecret) {  NSString *_oAuthNonce = [NSString ab_GUID];  NSString *_oAuthTimestamp = [NSString stringWithFormat:@"%d", (int)[[NSDate date] timeIntervalSince1970]];  NSString *_oAuthSignatureMethod = @"HMAC-SHA1";  NSString *_oAuthVersion = @"1.0";  NSMutableDictionary *oAuthAuthorizationParameters = [NSMutableDictionary dictionary];  [oAuthAuthorizationParameters setObject:_oAuthNonce forKey:@"oauth_nonce"];  [oAuthAuthorizationParameters setObject:_oAuthTimestamp forKey:@"oauth_timestamp"];  [oAuthAuthorizationParameters setObject:_oAuthSignatureMethod forKey:@"oauth_signature_method"];  [oAuthAuthorizationParameters setObject:_oAuthVersion forKey:@"oauth_version"];  [oAuthAuthorizationParameters setObject:_oAuthConsumerKey forKey:@"oauth_consumer_key"];  if(_oAuthToken)   [oAuthAuthorizationParameters setObject:_oAuthToken forKey:@"oauth_token"];  // get query and body parameters  NSDictionary *additionalQueryParameters = [NSURL ab_parseURLQueryString:[url query]];  NSDictionary *additionalBodyParameters = nil;  if(body) {   NSString *string = [[NSString alloc] initWithData:body encoding:NSUTF8StringEncoding];   if(string) {    additionalBodyParameters = [NSURL ab_parseURLQueryString:string];   }  }  // combine all parameters  NSMutableDictionary *parameters = [oAuthAuthorizationParameters mutableCopy];  if(additionalQueryParameters) [parameters addEntriesFromDictionary:additionalQueryParameters];  if(additionalBodyParameters) [parameters addEntriesFromDictionary:additionalBodyParameters];  // -> UTF-8 -> RFC3986  NSMutableDictionary *encodedParameters = [NSMutableDictionary dictionary];  for(NSString *key in parameters) {   NSString *value = [parameters objectForKey:key];   [encodedParameters setObject:[value ab_RFC3986EncodedString] forKey:[key ab_RFC3986EncodedString]];  }  NSArray *sortedKeys = [[encodedParameters allKeys] sortedArrayUsingFunction:SortParameter context:(__bridge void *)(encodedParameters)];  NSMutableArray *parameterArray = [NSMutableArray array];  for(NSString *key in sortedKeys) {   [parameterArray addObject:[NSString stringWithFormat:@"%@=%@", key, [encodedParameters objectForKey:key]]];  }  NSString *normalizedParameterString = [parameterArray componentsJoinedByString:@"&"];  NSString *normalizedURLString;  if ([url port] == nil) {   normalizedURLString = [NSString stringWithFormat:@"%@://%@%@", [url scheme], [url host], [url path]];  } else {   normalizedURLString = [NSString stringWithFormat:@"%@://%@:%@%@", [url scheme], [url host], [url port], [url path]];  }  NSString *signatureBaseString = [NSString stringWithFormat:@"%@&%@&%@",           [method ab_RFC3986EncodedString],           [normalizedURLString ab_RFC3986EncodedString],           [normalizedParameterString ab_RFC3986EncodedString]];  NSString *key = [NSString stringWithFormat:@"%@&%@",       [_oAuthConsumerSecret ab_RFC3986EncodedString],       [_oAuthTokenSecret ab_RFC3986EncodedString]];  NSData *signature = HMAC_SHA1(signatureBaseString, key);  NSString *base64Signature = [signature base64EncodedString];  // PARKER CHANGE: changed oAuthAuthorizationParameters to parameters  NSMutableDictionary *authorizationHeaderDictionary = [parameters mutableCopy];  [authorizationHeaderDictionary setObject:base64Signature forKey:@"oauth_signature"];  NSMutableArray *authorizationHeaderItems = [NSMutableArray array];  for(NSString *key in authorizationHeaderDictionary) {   NSString *value = [authorizationHeaderDictionary objectForKey:key];   // PARKER CHANGE: removed quotes that surrounded each value   [authorizationHeaderItems addObject:[NSString stringWithFormat:@"%@=%@",             [key ab_RFC3986EncodedString],             [value ab_RFC3986EncodedString]]];  }  // PARKER CHANGE: changed concatentation string from ", " to "&"  NSString *authorizationHeaderString = [authorizationHeaderItems componentsJoinedByString:@"&"]; //  authorizationHeaderString = [NSString stringWithFormat:@"OAuth %@", authorizationHeaderString];  return authorizationHeaderString; } 

使用方法如下：

#pragma mark - 请求方法 -(void) connentSign{  //设置食物ID  NSDictionary *params = @{@"food_id" : @"33690"};  //设置请求参数和方法名  [self makeRequestWithMethod:@"food.get" parameters:params completion:^(NSDictionary *data) {  }]; } //开始发送请求 - (void) makeRequestWithMethod:(NSString *)method      parameters:(NSDictionary *)params      completion:(void (^)(NSDictionary *data))completionBlock {  NSMutableDictionary *parameters = [params mutableCopy];  [parameters addEntriesFromDictionary:[self defaultParameters]];  [parameters addEntriesFromDictionary:@{ @"method" : method }];  NSString *queryString = [self queryStringFromDictionary:parameters];  NSData *data    = [NSData dataWithBytes:[queryString UTF8String] length:queryString.length];  NSString *authHeader  = OAuthorizationHeader([NSURL URLWithString:FAT_SECRET_API_ENDPOINT],              @"GET",              data,              @"9921d3f511a542a8b32b8841bb1d62ed",              @"f8fa1d96494046c69159099ab153ea1e",              nil,              @"");  [self.manager GET:[FAT_SECRET_API_ENDPOINT stringByAppendingFormat:@"?%@", authHeader] parameters:nil success:^(AFHTTPRequestOperation *operation, id responseObject) {   NSLog(@"%@",responseObject);  } failure:^(AFHTTPRequestOperation *operation, NSError *error) {  }]; } - (NSDictionary *) defaultParameters {  return @{ @"format": @"json" }; } - (NSString *) queryStringFromDictionary:(NSDictionary *)dict {  NSMutableArray *entries = [@[] mutableCopy];  for (NSString *key in dict) {   NSString *value = [dict objectForKey:key];   [entries addObject:[NSString stringWithFormat:@"%@=%@", key, value]];  }  return [entries componentsJoinedByString:@"&"]; } 

然后我们就可以Happy programming!

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