ASIHTTPRequest: incorrect NSStringEncoding value 0x0000 detected - encoding

Incorrect NSStringEncoding value 0x0000 detected. Assuming
NSStringEncodingASCII. Will stop this compatiblity mapping behavior in
the near future.
When I was using ASIHTTPRequest, I keep getting this error(50% of the times), what's wrong with it?
I assume the URL I passed in is correct, as it does not contain any space or strange character, maybe it is the result string having some unrecognized character?

Copying my answer from https://stackoverflow.com/q/8251175/918764
The error is not that your data isn't encoded correctly, it's almost certainly that you're requesting some kind of string data from an ASIHTTPRequest object that doesn't have an encoding set yet - this will happen if the request failed to connect to the server, or if the server didn't send an understandable encoding header.
This notably happens if you call [asiHttpRequest getResponseString] before a valid response has been returned and the request encoding has been set (i.e. couldn't connect to server).
The easiest way to workaround this warning is by editing the ASIHTTPRequest class, remove the #synthesize responseEncoding and adding a simple custom getter/setter so you can return the default encoding if the response encoding isn't set:
- (NSStringEncoding) responseEncoding
{
return responseEncoding || self.defaultResponseEncoding;
}
- (void) setResponseEncoding:(NSStringEncoding)_responseEncoding
{
responseEncoding = _responseEncoding;
}
There's also a more specific workaround for the getResponseString method, which I think is the only place that uses the encoding without checking for a value - since the encoding should be set for any non-zero length response:
- (NSString *)responseString
{
NSData *data = [self responseData];
if (!data) {
return nil;
}
// --- INSERT THIS BLOCK ---
// If the 'data' is present but empty, return a simple empty string
if (data.length == 0) {
return #"";
}
//assert(self.responseEncoding); // if you're into runtime asserts, uncomment this
// --- END OF BLOCK TO INSERT ---
return [[[NSString alloc] initWithBytes:[data bytes] length:[data length] encoding:[self responseEncoding]] autorelease];
}

Related

NSMutableString becomes (null) when converted from NSData with length 4000+

I'm sending XML request to some server and getting some response data from it using NSURLConnection:
-(void)connectionDidFinishLoading:(NSURLConnection *)connection
{
NSMutableString *receivedString = [[NSMutableString alloc] initWithData:_receivedData encoding:NSUTF8StringEncoding];
NSLog(#"Size of DATA: %d",[_receivedData length]);
NSLog(#"Body: %#", receivedString);
}
When length of my data is about 4000 - I can normally see the received data in output. But when length of data becomes greater (6000, 10000, etc.), Output shows that my receivedString becomes null!
How can I still save my data to the string, when it's length becomes greater? Thank you.
Are you sure your data is encoded with NSUTF8StringEncoding? Double check the data being returned to you. initWithData:encoding: will return nil if the data is not properly represented by the encoding.
An easy way to test this is to use the same data object, and create a string with incremental pieces of the same data until it fails, then look at the byte that causes it to fail.
I'd bet a piece of southern fried catfish that you have an improperly (or mismatched) encoded byte in that data.

Why does SBJson JSON parsing only get the last key of interest?

I am using the following JSON: http://www.kb.dk/tekst/mobil/aabningstider_en.json
When I try to parse it by the key "location" as such:
// get response in the form of a utf-8 encoded json string
NSString *jsonString = [[[NSString alloc] initWithData:responseData encoding:NSUTF8StringEncoding] stringByTrimmingCharactersInSet:[NSCharacterSet newlineCharacterSet]];
// get most parent node from json string
NSDictionary *json = [jsonString JSONValue];
// get key-path from jason up to the point of json object
NSDictionary *locations = [json objectForKey:#"location"];
NSLog( #"%#", locations );
// iterate through all of the location objects in the json
for (NSDictionary *loc in locations )
{
// pull library name from the json object
NSString *name = [loc valueForKey:#"name"];
// add library data table arrays respectively
[ libraryNames addObject: ( ( name == nil | name.length > 0 ) ? name : #"UnNamed" ) ];
}
When I print the the object locations via NSLog:
{
address = "Universitetsparken 4, 3. etage, 2100 K\U00f8benhavn \U00d8";
desc = "";
lastUpdated = "";
latlng = "55.703124,12.559596";
link = "http://www.farma.ku.dk/index.php?id=3742";
name = "Faculty of Pharmaceutical Sciences Library";
parts = {
part = {
hour = {
day = "5.June Constitution Day (Denmark)";
open = Closed;
};
hours = {
hour = {
day = Friday;
open = "10-16";
};
};
name = main;
};
};
}
Which is only the last value for the "location" keys. Am I doing something wrong?
I tried validating the JSON via http://jsonlint.com/, however when I'd put in the JSON URL as above, it said "valid" - still only the last "locations" key was shown", however if I copy-paste it, it will not validate the JSON, and has to be fixed by removing new-lines from the string.
Also, when i try to parse the JSON and get the "name" fields, I get the following exception:
2012-05-08 15:37:04.941 iPhone App Tabbed[563:f803] *** Terminating app due to uncaught exception 'NSUnknownKeyException', reason: '[<__NSCFString 0x68bfe70> valueForUndefinedKey:]: this class is not key value coding-compliant for the key name.'
*** First throw call stack:
(0x13dc052 0x156dd0a 0x13dbf11 0x9d2f0e 0x941841 0x940ca9 0x4593 0xf964e 0x114b89 0x1149bd 0x112f8a 0x112e2f 0x1148f4 0x13ddec9 0x365c2 0x3655a 0x25b569 0x13ddec9 0x365c2 0x3655a 0xdbb76 0xdc03f 0xdbbab 0x25dd1f 0x13ddec9 0x365c2 0x3655a 0xdbb76 0xdc03f 0xdb2fe 0x5ba30 0x5bc56 0x42384 0x35aa9 0x12c6fa9 0x13b01c5 0x1315022 0x131390a 0x1312db4 0x1312ccb 0x12c5879 0x12c593e 0x33a9b 0x281d 0x2785)
terminate called throwing an exception(lldb)
It would make more sense if the "locations" tag was an array object enclosed by square brackets ([]), however right now it's only an sequence of normal key-value pairs... Sadly, that's the JSON I have to work with.
Please help and thanks a great deal! :)
Sincerely,
Piotr.
The JSON you've got to work with may be valid, but it doesn't make much sense. It has one big dictionary with the location key repeated many times. Most JSON parser will simply return the last value for the repeated key. It would be best if you could change the structure to use an array instead, but if you cannot there's still hope. You can read the stream and stuff the values from the location keys into an array as they come out of it. This is how you'd do that:
#interface BadJsonHelper : NSObject
#property(strong) NSMutableArray *accumulator;
#end
#implementation BadJsonHelper
- (void)parser:(SBJsonStreamParser *)parser foundArray:(NSArray *)array {
// void
}
- (void)parser:(SBJsonStreamParser *)parser foundObject:(NSDictionary *)dict {
[accumulator addObject:dict];
}
#end
You can drop that little helper class at the top of your file, outside the #implementation section of the class where you're doing your work. (There's no need for the #interface and #implementation being in different files.)
In your code, you would use it like this:
BadJsonHelper *helper = [[BadJsonHelper alloc] init];
helper.accumulator = [NSMutableArray array];
SBJsonStreamParserAdapter *adapter = [[SBJsonStreamParserAdapter new] init];
adapter.delegate = helper;
adapter.levelsToSkip = 1;
SBJsonStreamParser *parser = [[SBJsonStreamParser alloc] init];
parser.delegate = adapter;
switch ([parser parse: responseData]) {
case SBJsonStreamParserComplete:
NSLog(#"%#", helper.accumulator);
break;
case SBJsonStreamParserWaitingForData:
NSLog(#"Didn't get all the JSON yet...");
break;
case SBJsonStreamParserError:
NSLog(#"Error: %#", parser.error);
break;
}
This example was originally adapted from the following test:
https://github.com/stig/json-framework/blob/master/Tests/StreamParserIntegrationTest.m
Update: I created a fully functional example project that loads the JSON asynchronously and parses it. This is available from github.
The JSON is valid, however there is a basic problem regarding the definition of the array of items.
Instead of defining an array of locations using brackets, the JSON redefines the same location key/value pair over and over again. In other words JSON initially says the value of location is the collection with name "The Black Diamond", but immediately after it redefines it with the collection with name "Faculty Library of Humanities" and so on till the last location Faculty of Pharmaceutical Sciences Library".
The same is true for parts and hours.
If you can't fix the result of the JSON and you really need to get it working you may want to modify the JSON removing the "location" keys and adding brackets properly.
Edit
Alternatively you may use an NSScanner and process the JSON result manually. Kinda hacky but it will work as long as the JSON format doesn't change significantly.
Edit
This snipped of code should do the work...
NSString *jsonString = [[[NSString alloc] initWithData:responseData encoding:NSUTF8StringEncoding] stringByTrimmingCharactersInSet:[NSCharacterSet newlineCharacterSet]];
int indx = 1;
for (;;)
{
NSRange locationRange = [jsonString rangeOfString:#"\"location\":"];
if (locationRange.location == NSNotFound) break;
jsonString = [jsonString stringByReplacingCharactersInRange:locationRange
withString:[NSString stringWithFormat:#"\"location%d\":", indx++]];
}
NSDictionary *locations = [json objectForKey:#"location"];
As you can see, the result of JSON parsing by SBJson is a NSDictionary. A dictionary contains key/value pairs, and the keys are unique identifiers for the pairs.
The JSON data you need to handle is valid but not a good one. Per RFC 4627 - 2.2:
An object structure is represented as a pair of curly brackets surrounding zero or more name/value pairs (or members). A name is a string. A single colon comes after each name, separating the name from the value. A single comma separates a value from a following name. The names within an object SHOULD be unique.
Things like jQuery can parse the JSON also, but the result is the same as SBJson (the last one as the one). See Do JSON keys need to be unique?.
It is not a MUST, but it's still not a good practice. It would be much easier if you are able to change the structure of the JSON data on the server side (or even on the client side after receiving it) rather than parsing it as is.

iPhone - Decrypting an AES-encrypted message with a different key than the one used to encrypt

I'm just coding basic "encrypt" and "decrypt" methods for AES on iPhone, using CCrypt.
I've been running a few tests and I was really struck about finding that, sometimes, if you try to decrypt an encrypted text using a key different than the one that was used to encrypt the plain text CCrypt would not return any errors.
Here is an example:
- (void) testDecryptTextWithTheWrongKey {
NSData *encryptKey = [Base64 decodeBase64WithString:#"+LtNYThpgIlQs2CaL00R6AuG2C/i6U1Vt1+6wfFeFMk="];
NSData *decryptKey = [Base64 decodeBase64WithString:#"yg7BvhM8npVGpAFpAESDn3IRWpe6qeQWaa1rwHiTsyU="];
NSString *plainText = #"The text to be encrypted";
NSData *plainTextData = [plainText dataUsingEncoding:NSUTF8StringEncoding];
NSError *error = nil;
NSData *encrypted = [LocalCrypto encryptText:plainTextData key:encryptKey error:&error];
assertThat(error, nilValue());
assertThat(encrypted, notNilValue());
error = nil;
NSData *decrypted = [LocalCrypto decryptText:encrypted key:decryptKey error:&error];
assertThat(error, notNilValue());
assertThat(decrypted, nilValue());
}
My encrypt and decrypt methods defined in LocalCrypto simply call an internal "executeCryptoOperation" method indicating that they want to encrypt or decrypt:
+ (NSData *) executeCryptoOperation:(CCOperation)op key:(NSData *) key input:(NSData *) input error:(NSError **)error {
size_t outLength;
NSMutableData *output = [NSMutableData dataWithLength:input.length + kCCBlockSizeAES128];
CCCryptorStatus result = CCCrypt(op, // operation
kCCAlgorithmAES128, // Algorithm
kCCOptionPKCS7Padding | kCCOptionECBMode, // options
key.bytes, // key
key.length, // keylength
nil, // iv
input.bytes, // dataIn
input.length, // dataInLength,
output.mutableBytes, // dataOut
output.length, // dataOutAvailable
&outLength); // dataOutMoved
if (result == kCCSuccess) {
output.length = outLength;
} else {
*error = [NSError errorWithDomain:kCryptoErrorDomain code:result userInfo:nil];
return nil;
}
return output;
}
Well, my question is: is it normal that CCrypt returns kCCSuccess when we try to decrypt the encrypted text with a different key than the one used during the encrpytion? Am I missing something or doing something wrong?
It is true that even when CCrypt returns success for the decryption, I can't get a proper NSString out of the resulting data but I would certainly expect CCrypt to return some sort of error in this situation (as Java would probably do).
If this is the normal behavior, how am I supposed to know if the decrypt operation returned the real plain text or just a bunch of bytes that don't make any sense?
There is a similar question here, but the answer doesn't really convince me: Returning wrong decryption text when using invalid key
Thanks!
There are cipher algorithms which include padding (like the PKCS#5 padding in your Java implementation), and there are ones which don't.
If your encryption algorithm used padding, the corresponding decryption algorithm expects that there will be well-formed padding in the decrypted plaintext, too. This serves as a cheap partial integrity check, since with a wrong key the output likely will not have a right padding. (The chance that a random n-byte block (n=16 for AES) has a valid PKCS#5 padding is 1/256 + 1/(256^2) + ... + 1/(256^n), which is only slightly more than 1/256.)
It might be that your objective-C CCCrypt function does not check that the padding is valid, only its last byte (or even only some bits of this last byte), to see how many bytes were padded (and are now to be cut off).
If you want to make sure that the key is right, encrypt some known part of the plaintext, and error out if it is not in the decrypted part. (But don't do this with ECB mode, see below.)
If you also want to make sure that the data was not modified, also use a MAC, or use a combined authenticated encryption mode of operation for your block cipher.
Another note: You should not use ECB mode, but instead a secure mode of operation (about any other mode indicated in this article and supported by your implementation will do - standard nowadays is CBC or CTR mode). Some modes (like CFB, OFB and CTR) don't need padding at all.
You're missing the fact that the decryption function has no idea whatsoever what the plaintext (decrypted data) is supposed to look like.
As far as the decryption function is concerned, it got a key and a ciphertext from you, applied the decryption routine to the ciphertext using the key you provided, and no errors arose. Hence, success.
It's your job to verify that the plaintext you got was actually correct/on the format you expected it to be.

Incorrect NSStringEncoding value 0x0000 detected

I am using ASIHttpRequest library in iphone and when i try to do a GET request on the below URL i get this message and the request fails, please anyone if he/she has encountered this problem or know a possible solution to it please let me know. Secondly if i paste the link in the browser it works perfectly fine.
[URL]
http://www.rugsale.com/iphone/app/?type=product_list&params=id%3D334&ver=1.0&key=kaoud
[ERROR]
Incorrect NSStringEncoding value 0x0000 detected. Assuming NSStringEncodingASCII. Will stop this compatiblity mapping behavior in the near future.
Thx in advance
Regards
Syed Arsalan Pervez
www.saplogix.net
This notably happens if you call [asiHttpRequest getResponseString] before a valid response has been returned and the request encoding has been set (i.e. couldn't connect to server).
The easiest way to workaround this warning is by editing the ASIHTTPRequest class, remove the #synthesize responseEncoding and adding a simple custom getter/setter so you can return the default encoding if the response encoding isn't set:
- (NSStringEncoding) responseEncoding
{
return responseEncoding || self.defaultResponseEncoding;
}
- (void) setResponseEncoding:(NSStringEncoding)_responseEncoding
{
responseEncoding = _responseEncoding;
}
There's also a more specific workaround for the getResponseString method, which I think is the only place that uses the encoding without checking for a value - since the encoding should be set for any non-zero length response:
- (NSString *)responseString
{
NSData *data = [self responseData];
if (!data) {
return nil;
}
// --- INSERT THIS BLOCK ---
// If the 'data' is present but empty, return a simple empty string
if (data.length == 0) {
return #"";
}
//assert(self.responseEncoding); // if you're into runtime asserts, uncomment this
// --- END OF BLOCK TO INSERT ---
return [[[NSString alloc] initWithBytes:[data bytes] length:[data length] encoding:[self responseEncoding]] autorelease];
}
For me the problem was timeout wasn't enough. So it returns an empty response. So it gives this error because you'r trying to do something with an empty response. I increased the time for it. So it solved my problem.[request setTimeOutSeconds:200];
this is just saying that the encoding was nil, when a value was expected. Try doing a search for "encoding:nil" or "encoding:NULL" in your source code and replace it with a valid encoding, for example NSStringEncodingASCII...
This looks like something that's cropped up in the 4.2 SDK. I didn't see this until I updated my development environment myself.
All-Seeing Interactive will probably have to update the code to ensure compatibility.
The error is where you are creating a string. You don't supply an encoding which is required.

NSXMLParser rss issue NSXMLParserInvalidCharacterError

NSXMLParserInvalidCharacterError # 9
This is the error I get when I hit a weird character (like quotes copied and pasted from word to the web form, that end up in the feed). The feed I am using is not giving an encoding, and their is no hope for me to get them to change that. This is all I get in the header:
< ?xml version="1.0"?>
< rss version="2.0">
What can I do about illegal characters when parsing feeds? Do I sweep the data prior to the parse? Is there something I am missing in the API? Has anyone dealt with this issue?
NSString *dataString = [[[NSString alloc] initWithData:webData encoding:NSASCIIStringEncoding] autorelease];
NSData *data = [dataString dataUsingEncoding:NSUTF8StringEncoding allowLossyConversion:YES];
NSXMLParser *parser = [[NSXMLParser alloc] initWithData:data];
Fixed my problems...
The NSString -initWithData:encoding: method returns nil if it fails, so you can try one encoding after another until you find one that converts. This doesn't guarantee that you'll convert all the characters correctly, but if your feed source isn't sending you correctly encoded XML, then you'll probably have to live with it.
The basic idea is:
// try the most likely encoding
NSString xmlString = [[NSString alloc] initWithData:xmlData
encoding:NSUTF8StringEncoding];
if (xmlString == nil) {
// try the next likely encoding
xmlString = [[NSString alloc] initWithData:xmlData
encoding:NSWindowsCP1252StringEncoding];
}
if (xmlString == nil) {
// etc...
}
To be generic and robust, you could do the following until successful:
1.) Try the encoding specified in the Content-Type header of the HTTP response (if any)
2.) Check the start of the response data for a byte order mark and if found, try the indicated encoding
3.) Look at the first two bytes; if you find a whitespace character or '<' paired with a nul/zero character, try UTF-16 (similarly, you can check the first four bytes to see if you have UTF-32)
4.) Scan the start of the data looking for the <?xml ... ?> processing instruction and look for encoding='something' inside it; try that encoding.
5.) Try some common encodings. Definitely check Windows Latin-1, Mac Roman, and ISO Latin-1 if your data source is in English.
6.) If none of the above work, you could try removing all bytes greater than 127 (or substitute '?' or another ASCII character) and convert the data using the ASCII encoding.
If you don't have an NSString by this point, you should fail. If you do have an NSString, you should look for the encoding declaration in the <?xml ... ?> processing instruction (if you didn't already in step 4). If it's there, you should convert the NSString back to NSData using that encoding; if it's not there, you should convert back using UTF-8 encoding.
Also, the CFStringConvertIANACharSetNameToEncoding() and CFStringConvertEncodingToNSStringEncoding() functions can help get the NSStringEncoding that goes with the encoding name form the Content-Type header or the <?xml ... ?> processing instruction.
You can also remove that encoding line from xml like this:
int length = str.length >100 ? 100:str.length;
NSString*mystr= [str stringByReplacingOccurrencesOfString:#"encoding=\".*?\""
withString:#""
options:NSRegularExpressionSearch
range:NSMakeRange(0, length)];