How to use JSON request from YQL stock data?

Question

I just used this answer to set up a data request from Yahoo Finance. If you take a look at the post, you'll see it returns a dictionary of data (in this case, bids) and keys (symbols). Just to test it, I used this code, but it continues to crash:

NSArray *tickerArray = [[NSArray alloc] initWithObjects:@"AAPL", nil];
NSDictionary *quotes = [self fetchQuotesFor:tickerArray];

NSLog(@"%@",[quotes valueForKey:@"AAPL"]);

Can you point out what I'm doing wrong? I need to get a string containing the data for the symbols I ask for.

PLEASE NOTE:My code is using the code that this post was based on, i.e. this.

Try with minimum two tickers instead of one. – Rick Aug 10 '12 at 07:40 — Rick, Aug 10 '12 at 07:40

Jessedc · Accepted Answer · 2012-08-12T21:13:58.290

The code you liked to is making the wrong assumption about the shape of the JSON data coming back from the API and you're getting a standard KVC error. reason: '[<__NSCFString 0x7685930> valueForUndefinedKey:]: this class is not key value coding-compliant for the key BidRealtime.'

With some debugging I got it working...

Based on your input array and by slightly modifying the function linked too, you need to access the quote like so:

#define QUOTE_QUERY_PREFIX @"http://query.yahooapis.com/v1/public/yql?q=select%20symbol%2C%20BidRealtime%20from%20yahoo.finance.quotes%20where%20symbol%20in%20("
#define QUOTE_QUERY_SUFFIX @")&format=json&env=store%3A%2F%2Fdatatables.org%2Falltableswithkeys&callback="

+ (NSDictionary *)fetchQuotesFor:(NSArray *)tickers {
  NSMutableDictionary *quotes;

  if (tickers && [tickers count] > 0) {
    NSMutableString *query = [[NSMutableString alloc] init];
    [query appendString:QUOTE_QUERY_PREFIX];

    for (int i = 0; i < [tickers count]; i++) {
      NSString *ticker = [tickers objectAtIndex:i];
      [query appendFormat:@"%%22%@%%22", ticker];
      if (i != [tickers count] - 1) [query appendString:@"%2C"];
    }

    [query appendString:QUOTE_QUERY_SUFFIX];

    NSData *jsonData = [[NSString stringWithContentsOfURL:[NSURL URLWithString:query] encoding:NSUTF8StringEncoding error:nil] dataUsingEncoding:NSUTF8StringEncoding];
    NSDictionary *results = jsonData ? [NSJSONSerialization JSONObjectWithData:jsonData options:0 error:nil] : nil;

    NSDictionary *quoteEntry = [results valueForKeyPath:@"query.results.quote"];
    return quoteEntry;
  }
  return quotes;
}

You'll notice the difference between the code I've posted here and the function you linked too is the final parsing of quoteEntry. I worked out what it was doing with some breakpoints, specifically on all exceptions that lead me to the exact line.

Your method seems to be returning an array of NULL objects. The method I used I got to work, but only sometimes, so I would like to use your way. Can you show me an example of you using this method? — Redneys, Aug 16 '12 at 16:23

score 0 · Answer 2 · answered Sep 07 '13 at 17:48

All you have to do is initialize the NSMutableDictionary!

NSMutableDictionary *quotes = [[NSMutableDictionary alloc] init];

BTW the guy above is totally NOT making use of the quotes dict. straight up returning the quoteEntry. Skipping one step. :)

How to use JSON request from YQL stock data?

2 Answers2