Currently, I have within my iPhone app a URL with which contains a JSON object that I must parse.
I am able to fetch the JSON object, convert the object to an NSString, now the issue is parsing the object/NSString object.
I am currently using SBJSON.
How do I go about iterating through the key elements of the JSON object using SBJSON's framework?
{
"status":"SUCCESS",
"fields":[
{
"type":"instant",
"field":"GenerationPower",
"label":"now",
The JSON object is MUCH larger than just these keys and key elements but once this issue is resolved, I'm sure the rest of the JSON object will be easy since i'll have a reference.
Thank you Stackoverflow!
EDIT:
Here's some code to clarify my issue.
+ (NSString *) pullingInfo
{
NSURL *solarWebURL = [NSURL URLWithString:myurl];
if (solarWebURL)
{
NSLog(#"Calling: %#", solarWebURL);
NSData *jsonData = [NSData dataWithContentsOfURL:solarWebURL];
NSString *jsonString = [[NSString alloc] initWithData:jsonData encoding:NSUTF8StringEncoding];
return jsonString;
}
NSString* errorMessage = #"Error reading URL";
return errorMessage;
}
+ (NSDictionary *) jsonDictionaryObject
{
NSDictionary * jsonDictionary = [[NSDictionary alloc] init];
NSString * monroeString = [MonroeParser pullingInfo];
return jsonDictionary;
}
So as I said before, I have already loaded the JSON object into an NSString object "jsonString". Now I would like to start parsing the string.
I figure I may not even need to use JSON's framework for parsing, I can probably just parse the NSString using NSString conventions provided by Apple.
Any idea's? But maybe this isn't efficient....
Sine you are using SBJSON, why are you even converting the NSData to an NSString? You can use -objectWithData method for SBJSONParser to directly read the NSData into an NSDictionary.
http://sbjson.org/api/3.2/Classes/SBJsonParser.html#//api/name/objectWithData:
Let pullingInfo return an id. And in you calling function check if the id is of type NSDictionary or NSArray and parse accordingly.
Related
I am new to developing and stackoverflow please help me. i am trying to do a simple application where the YQL link is used to get local data and display it in table format. For that i am converting the data into dictionary , later i want to send it into table. But when i tried to convert data to Dictionary it says null. Please help me. Check the Screenshot below. Thanks in advance.
NSString *str = #"https://query.yahooapis.com/v1/public/yql?q=select%20*%20from%20local.search%20where%20zip%3D'94085'%20and%20query%3D'pizza'&diagnostics=true";
Here i took json query into a string (*str)
NSData *data = [NSData dataWithContentsOfURL:[NSURL URLWithString:str]];
// NSString *stringFromData = [[NSString alloc]initWithData:data encoding:NSUTF8StringEncoding];
// NSLog(#"%#", stringFromData);
When i tried to implement this commented code im getting the result as expected, but i want to put all the data into dictionary and display it, so i tried to convert the data into dictionary
NSDictionary *dataFromWeb = [NSJSONSerialization JSONObjectWithData:data options:NSJSONReadingMutableContainers error:nil];
NSDictionary *queryDict = [dataFromWeb objectForKey:#"query"];
NSDictionary *results = [dataFromWeb objectForKey:#"results"];
NSString *allResults = [queryDict objectForKey:#"Results"];
NSLog(#"%#", dataFromWeb);
}
The response returning from Yahoo API is XML by default. You should append format=json to the querystring in order to get the response in JSON format so you can parse it using NSJSONSerialization class:
https://query.yahooapis.com/v1/public/yql?format=json&q=select...
Your Api Return xml data so you need to do xml parsing
NSJSONSerialization is used for json parsing
NSString *str = #"https://query.yahooapis.com/v1/public/yql?q=select%20*%20from%20local.search%20where%20zip%3D'94085'%20and%20query%3D'pizza'&diagnostics=true";
NSURL *UrlFromStr = [NSURL URLWithString:str];
hit this UrlFromStr on your browser you see it return xml data not json
use NSXMLParser to parse xml data
Please Use NSXMLParser To Parse xml data instead of NSJSONSerialization.
NSJSONSerialization is used to parse JSON data.
Declare in .h file
#property (nonatomic, strong) NSXMLParser *xmlParser;
in .m file.
NSString *str = #"https://query.yahooapis.com/v1/public/yql?q=select%20*%20from%20local.search%20where%20zip%3D'94085'%20and%20query%3D'pizza'&diagnostics=true";
NSData *data = [NSData dataWithContentsOfURL:[NSURL URLWithString:str]];
self.xmlParser = [[NSXMLParser alloc] initWithData:data];
self.xmlParser.delegate = self;
// Initialize the mutable string that we'll use during parsing.
self.foundValue = [[NSMutableString alloc] init];
// Start parsing.
[self.xmlParser parse];
The format of objects you wanna parse is XML,but you use the class of ParseJSON to parse it ,so it return NULL.You can use the class of NSXML to parse it and then set its delegate to execute the related methods...Good luck to you ..
your Api is not a json its XML format use the XML Parser, visit below link,
http://www.theappguruz.com/blog/xmlparsing-with-nsxmlparser-tutorial
hope its helpful.
I came across a problem with string encoding in ios development. The story is as below:
I create some values in Chinese and then create a NSDictionary for those values, the dictionary is used as parameter for network request:
- (void)createActivity
{
NSString *actionTheme = titleF.text;
NSString *actionTitle = biaotiF.text;
NSDictionary *dic = [NSDictionary dictionaryWithObjectsAndKeys:actionTheme, #"actionTheme", actionTitle, #"actionTitle",nil];
[self networkrequest:];
}
Then some work has been done for the dictionary:
Transform the dictionary to the form of JSON as the type of NSString.
NSData* jsonData = [NSJSONSerialization dataWithJSONObject:param options:NSJSONWritingPrettyPrinted error:nil];
NSString *jsonString = [[NSString alloc] initWithData:jsonData encoding:NSUTF8StringEncoding];
Encoding the string , because of Chinese word in the string.
NSString *urlEncodedString = [jsonString stringByAddingPercentEscapesUsingEncoding:NSUTF8StringEncoding];
At last a full url was create with the string above:
http://app.ic100.com/action/add?paramJson=%7B%22actionTheme%22%3A%22%E6%88%96%E8%80%85%E5%92%8C%E7%94%9F%E6%B4%BB%22%2C%22actionSite%22%3A%22%E5%8E%A (something like this)
I use the third party "ASIFormDataRequest" for network request, and I also set the StringEncoding:
ASIFormDataRequest *requstHttp = [[ASIFormDataRequest alloc] init];
[requstHttp setStringEncoding:NSUTF8StringEncoding];
....
All the datas has been sent to the server successfully, but when I request these data from the server and show then on the iphone. It turn to be unreadable text:
I have carefully checked all the place that I should encode or decode the string, and only utf8 is used. What`s more , for the server side , no other encoding used either. And my colleague has tested sent data from Android platform, no problem. So I think maybe I have missed some points.
Any advise?
By using the class Base64 you can encode or decode the string.
Add Base64 class in your project from HERE
see the mehode in class to encode.
Encode:
+ (NSString *)stringWithBase64EncodedString:(NSString *)string;
- (NSString *)base64EncodedString;
Decode:
- (NSString *)base64DecodedString;
I have the following json string that should be sent to the backend
{
id = "MU_200255802";
keywords = (
Talk,
games,
meetup,
time,
meet,
"Time for Another Game"
);
}
So before this JSON I have the java servlet URL something like
http://....net/servletName?
How should I urlencode the json string and the url because even after trying several options, I keep getting bad url as an error back in the delegate method. What is the right way to do it/
I tried encoding using
NSString *urlStringEncoded = [[NSString stringWithString:urlString] stringByAddingPercentEscapesUsingEncoding:NSUTF8StringEncoding];
and also used other encoding formats too.
Use this to create json string
NSError *error;
NSData *jsonData = [NSJSONSerialization dataWithJSONObject:#"Your object" options:NSJSONWritingPrettyPrinted error:&error];
NSString *jsonString = [[NSString alloc] initWithData:jsonData encoding:NSUTF8StringEncoding];
You can use Google Toolbox for Mac, check it out here, https://code.google.com/p/google-toolbox-for-mac/source/checkout
There are Classes named GTMNSString+HTML,GTMNSString+XML,GTMNSString+URLArguments, which contains many encoding methods for you.
In my app, I am making a share function that sends another user an email with a URL to open my app and pass parameters. I googled around for a bit and came up with this.
I know its a terrible example, but that is all I could find. Since I need to pass a NSNumber, a NSDate, and an NSString, I figured this would be the most convenient way to do so. Right now, I cannot make sense of that code. I went ahead and got the SBJson library, which is what he appears to be using. Can someone help me out on this?
You don't have to use a library for JSON Serialization in iOS. From iOS 5.0 onwards there is a class NSJSONSerialization is available for doing this. https://developer.apple.com/library/ios/documentation/foundation/reference/nsjsonserialization_class/Reference/Reference.html
Consider this code for converting list of contacts to json string
+(NSString*) jsonStringRepresentationOfSelectedReceiptients:(NSArray*) contactsList {
NSMutableArray* contactsArray = [[NSMutableArray alloc]init];
for (ContactObject *contactObj in contactsList) {
NSDictionary* ltPair = #{#"phone_no": [NSNumber numberWithLongLong:contactObj.phoneNo, #"email_id": contactObj.emailId, #"display_name": contactObj.displayName], #"creation_date": [NSDate dateWithTimeIntervalSince1970:contactObj.timeStamp]]};
[contactsArray addObject:ltPair];
}
NSData *jsonData=[NSJSONSerialization dataWithJSONObject:contactsArray options:NSJSONWritingPrettyPrinted error:nil];
NSString *jsonString = [[NSString alloc] initWithData:jsonData encoding:NSUTF8StringEncoding];
NSLog(#"json string: %#", recptJson);
return jsonString;
}
If you have proper NSDate instead of time stamp, u can directly use it.
Hope this helps.
Here are my method's to use RNCryptor to encrypt/decrypt a JSON string that I am sending to the web service. I am using a static IV variable which may be bad practice but please don't focus on that. Here is how I'm doing it:
Note: I'm using Matt Gallagher's NSData+Base64 category found here (at bottom of page)
-(NSString*)encryptString:(NSString*)plaintext withKey:(NSString*)key error:(NSError**)error{
NSData *data = [plaintext dataUsingEncoding:NSUTF8StringEncoding];
NSData *encryptionKey = [NSData dataFromBase64String:key];
NSData *IV = [NSData dataFromBase64String:ENCRYPTION_IV];
RNCryptorEngine *engine = [[RNCryptorEngine alloc] initWithOperation:kCCEncrypt settings:kRNCryptorAES256Settings key:encryptionKey IV:IV error:error];
[engine addData:data error:error];
NSData *encryptedData = [engine finishWithError:error];
NSString *based64Encrypted = [encryptedData base64EncodedString];
NSLog(#"Encrytped: %#", based64Encrypted);
return based64Encrypted;
}
-(NSString*) decryptString:(NSString*)cipherText withKey:(NSString*)key error:(NSError**)error;{
NSData *data = [NSData dataFromBase64String:cipherText];
NSData *encryptionKey = [NSData dataFromBase64String:key];
NSData *IV = [NSData dataFromBase64String:ENCRYPTION_IV];
RNCryptorEngine *engine = [[RNCryptorEngine alloc] initWithOperation:kCCDecrypt settings:kRNCryptorAES256Settings key:encryptionKey IV:IV error:error];
[engine addData:data error:error];
NSData *decryptedData = [engine finishWithError:error];
NSString *decryptedString = [[NSString alloc] initWithData:decryptedData encoding:NSUTF8StringEncoding];
NSLog(#"Decrypted: %#", decryptedString);
return decryptedString;
}
When I use a string like hello world it works fine. When I use a string like {"username":"developer","password":"abcdefG*12"} I imagine it hase something to do with the encoding but I really know what to use.
when I encrypt that string I get a base64 string and when I try to decrypt that I get an empty string.
UPDATE
It looks like it's failing because of the : in the json string.
What's weirder is it only fails with the string is in json format, I thought it was the : cause I tried that first but upon further investigation if I broke any of the JSON requirements ,'s {'s }'s it stopped working. It works with the RNEncryptor however so I'm not sure what I'm doing wrong. Either way, I think we may redesign the current flow
UPDATE 2
Here is where I am calling these methods:
NSDictionary *credentials = #{#"username":#"developer",#"password":#"abcdefG*12"};
NSString *jsonString = [ credentials JSONStringWithOptions:JKSerializeOptionNone error:&error];
NSLog(#"json string: %#", jsonString); //OUTPUTS: {"username":"developer","password":"abcdefG*12"}
CCGEncryption *encryptionObject = [[CCGEncryption alloc] init]; //THIS IS THE OBJECT WHERE THE encrypt/decrypt methods are
NSString *encrypted = [encryptionObject encryptString:jsonString withKey:ENCRYPTION_KEY error:&error];
if(error){
NSLog(#"Error:%#", error); //NO ERROR
}
NSString *decrypted = [encryptionObject decryptString:encrypted withKey:ENCRYPTION_KEY error:&error];
if(error){
NSLog(#"Error:%#", error); //NO ERROR
}
NSLog(#"decrypted: %#", decrypted); //OUTPUT: decrypted:
You're not collecting the data returned by addData:. The engine encrypts/decrypts as you go so that you don't have to hold the entire plaintext and ciphertext in memory. It doesn't accumulate the data unless it has to (for padding reasons). I suspect that the tests that are working are of different lengths than the ones that aren't.
You are correct that using a fixed IV is bad practice. If you use the same IV and key in multiple messages, then it is possible for attackers to recover parts of your messages by comparing the ciphertexts. If you are using AES-CBC without a random IV and an HMAC, then your AES is insecure in several ways. That is the problem RNCryptor was built to address and why the data format looks the way it does.
#jbtule is correct that I didn't particularly mean for people to use the engine directly and haven't heavily documented it, but there's no problem using it, and I can document it better to support that. That said, the engine itself is insanely simple; I just created it as a way to share code between the encryptor and decryptor. There's not much reason to use RNCryptor if you're going to bypass most of the security it provides. For the above code, it'd be a lot simpler to just call the one-shot CCCrypt().