Making JSON from NSDictionary with the chars "_" and "/" - iphone

Question

EDIT 2: I no longer think "_" and "/" in the dictionary keys are the problem.
EDIT 3: I don't think the JSON is the problem any more, or the HTTP POST request. I don't know exactly what it is yet.
EDIT 4: Solved it. The data element had to be valid base64, or else couch refuses it. Didn't know that. Can't select my own answer yet.
I have a dictionary I want to convert to a JSON string.
This is the setup of my dictionary:
- (NSDictionary*) createDictionary
{
NSMutableDictionary *room = [[NSMutableDictionary alloc] init];
[room setObject:self.roomNumber forKey:#"roomNumber"];
[room setObject:self.floor forKey:#"floor"];
[room setObject:self.comment forKey:#"comment"];
[room setObject:self.type forKey:#"type"];
[room setObject:[NSNumber numberWithInt:self.status] forKey:#"status"];
[room setObject:[[NSMutableDictionary alloc] init] forKey:#"_attachments"];
NSMutableDictionary *attachments = [room objectForKey:[NSString stringWithFormat:#"_%#", #"attachments"]];
[attachments setObject:[[NSMutableDictionary alloc] init] forKey:#"picture"];
NSMutableDictionary *picture = [attachments objectForKey:#"picture"];
[picture setObject:#"text/plain" forKey:#"content_type"];
[picture setObject:#"BASE64" forKey:#"data"];
NSLog(#"Room: %#", room);
return room;
}
The problem is the "_" and "/" chars. When I print out the dictionary, it looks like this:
Room: {
"_attachments" = {
picture = {
"content_type" = "text/plain";
data = BASE64;
};
};
comment = 12;
floor = 12;
roomNumber = 12;
status = 0;
type = room;
}
Don't know why it ends up on one line there, but anyway, thats not important. The thing is that the keys with "_" or "/" ends up surrounded with "-marks, and my web endpoint receiving JSON can't read it. Does anyone know how I can solve this? I use couchdb and need the _ in from of the attachments key.
EDIT: I am using it, I pass my dictionary to NSJSONSerialization, calling the function dataWithJSONObject:options:error:. I store what I get from that function in a NSData object, and set it as the http body in the request I make. Content-Type is application/json. I also set the Content-length etc. Here is the function that makes the HTTP request. createDictionary is the function above.
// Make a JSON object from the dictionary
NSError *err;
NSData* jsonRoom = [NSJSONSerialization dataWithJSONObject:[room createDictionary]
options:NSJSONWritingPrettyPrinted
error:&err];
// Set up the http POST request
NSMutableURLRequest *request = [[NSMutableURLRequest alloc]
initWithURL:[NSURL URLWithString:[NSString stringWithFormat:#"%#%#", _baseURL, #"/peters_hotell"]]];
[request setHTTPMethod:#"POST"];
[request setValue:#"application/json" forHTTPHeaderField:#"Content-Type"];
[request setValue:[NSString stringWithFormat:#"%d", [jsonRoom length]]
forHTTPHeaderField:#"Content-length"];
[request setHTTPBody:jsonRoom];
NSLog(#"%#", jsonRoom);
// Fire the http POST request
//[NSURLConnection sendAsynchronousRequest:request queue:[[NSOperationQueue alloc] init] completionHandler:callback];`
Right now the sendRequest call is commented out, but when I use it, the server can't accept the request.
This is the response from couchdb:
Data: {
error = badmatch;
reason = false;
}
When I leave the attachments part out of the dictionary, couch does not complain. Basically what I am trying to create is this JSON (inline attachment): http://wiki.apache.org/couchdb/HTTP_Document_API#Inline_Attachments

Answer 1

The thing is that the keys [...] end up being surrounded with quotation marks, and my web endpoint receiving JSON can't read it.
No, it's the opposite: what you think is JSON isn't really JSON. JSON requires the keys to be quoted, it separates keys and values using colons (:) and not an equal sign, etc.
What you currently print out is the description of the NSDictionary object and it is not JSON. It's in the legacy NeXTSTEP-style property list format.
What you want to use is the NSJSONSerialization class.

Answer 2

When you are posting the url and Json Object, before posting it to server encode the URL string using the
stringByAddingPercentEscapesUsingEncoding
or
NSUTF8Encoding technique..

Answer 3

Thanks for the help! It led me to the answer. As it turns out, my POST request was refused because my data entry wasn't valid base64, so couch refused it.

Answer 4

Code:
#implementation NSString (NSString_Extended)
- (NSString *)urlEncoded
{
CFStringRef urlString = CFURLCreateStringByAddingPercentEscapes(
NULL,
(CFStringRef)self,
NULL,
(CFStringRef)#"!*'\"();:#&=+$,/?%#[]% ",
kCFStringEncodingUTF8 );
return [(NSString *)urlString autorelease];
}
#end