FatSecret API "invalid signature" - objective-c

Question

Using this repository I was not able to make the queries work when oauth_token must be provided. I always get invalid signature. Tried a lot of solutions and tweaks in the code, nothing worked. Please help.
This is the code from the git mentioned:
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:#"&"];
NSLog(#"normalizedParameters: %#", normalizedParameterString);
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]];
NSLog(#"signature base: %#", signatureBaseString);
NSString *key = [NSString stringWithFormat:#"%#&%#&",
[_oAuthConsumerSecret ab_RFC3986EncodedString],
[_oAuthTokenSecret ab_RFC3986EncodedString]];
NSLog(#"key codes: %#", key);
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];
NSLog(#"KEY: %#", key);
NSLog(#"VALUE: %#", value);
// 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];
NSLog(#"final: %#", authorizationHeaderString);
return authorizationHeaderString;
}
And this is how I'm calling it:
- (void) makeUserRequestWithMethod:(NSString *)method
parameters:(NSDictionary *)params
completion:(void (^)(NSDictionary *data))completionBlock {
NSLog(#"%s", __func__);
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],
#"POST",
data,
_oauthConsumerKey,
_oauthConsumerSecret,
_oAuthToken,
_oAuthTokenSecret
);
NSLog(#"header: %#", authHeader);
NSURL *url = [NSURL URLWithString:[FAT_SECRET_API_ENDPOINT stringByAppendingFormat:#"?%#", authHeader]];
[[[NSURLSession sharedSession] dataTaskWithURL:url completionHandler:^(NSData * _Nullable data, NSURLResponse * _Nullable response, NSError * _Nullable error) {
if (data) {
id JSON = [NSJSONSerialization JSONObjectWithData:data options:0 error:nil];
completionBlock(JSON);
} else {
completionBlock(nil);
}
}] resume];
}

Answer 1

I'm going to go out on a limb here and say that the code that others have proven to work is probably not at fault here, but rather first look at your own code. You say the error messages is "Invalid Signature" which sounds like it's a warning from the server you're calling, not from the code you're using.
[parameters addEntriesFromDictionary:[self defaultParameters]];
[parameters addEntriesFromDictionary:#{ #"method" : method }];
NSString *queryString = [self queryStringFromDictionary:parameters];
What happens inside [self defaultParameters] and are you 100% certain the parameters are appropriate (including spelling) for the API you're calling?
Have you verified that [self queryStringFromDictionary:parameters] prepares a properly formatting query string, and isn't introducing some error (non-escaped special characters, or percent encoding, for example)?