Obj-C: NSString crashes with error "Terminating app due to uncaught exception NSInvalidArgumentException"? - ios

Question

For some reason, the following line in my app is returned NULL, and thus, crashes my app:
NSString *address = [session user][#"field_street_address"][#"und"][0][#"safe_value"];
Which, I don't understand, as my console below states that data is returned for field_street_address. Is there something wrong with that line that I'm just not seeing? I've been staring at this for a while and I feel like I'm missing something obvious.
ViewController.m
NSDictionary *userDictInfo = (NSDictionary*) [NSKeyedUnarchiver unarchiveObjectWithData:[[NSUserDefaults standardUserDefaults] objectForKey:#"diosSession"]];
DIOSSession *session = [DIOSSession sharedSession];
[session setUser:userDictInfo];
[session user];
NSString *address = [session user][#"field_street_address"][#"und"][0][#"safe_value"];
Console ([session user] log):
2017-10-06 14:06:22.226970-0700 app[828:193706] {
sessid = "DRY0fOXtO_FZOIeowFVVq8oalaFnKSe";
"session_name" = SESS2bb8896be0f16543ff3c6a;
token = giCdHBuw967IaSxDB34m0Evzf1HI3DIK6;
user = {
access = 1507310936;
created = 1459875505;
data = {
"ckeditor_auto_lang" = t;
"ckeditor_default" = t;
"ckeditor_lang" = en;
"ckeditor_show_toggle" = t;
"ckeditor_width" = "100%";
};
"field_address" = {
und = (
{
format = "<null>";
"safe_value" = "1325 Fake Street";
value = "1325 Fake Street";
}
);
};
"field_childrenunder" = {
und = (
{
format = "<null>";
"safe_value" = No;
value = No;
}
);
};
"field_city" = {
und = (
{
format = "<null>";
"safe_value" = Van;
value = Van;
}
);
};
"field_emergency_facility" = {
und = (
{
format = "<null>";
"safe_value" = Yes;
value = Yes;
}
);
};
"field_first_name" = {
und = (
{
format = "<null>";
"safe_value" = Brittany;
value = Brittany;
}
);
};
"field_last_name" = {
und = (
{
format = "<null>";
"safe_value" = B;
value = B;
}
);
};
"field_phonenumber" = {
und = (
{
format = "<null>";
"safe_value" = 2369893091;
value = 2369893091;
}
);
};
"field_photo_path" = {
und = (
{
format = "<null>";
"safe_value" = "sites/default/files/stored/1507092784.jpg";
value = "sites/default/files/stored/1507092784.jpg";
}
);
};
"field_points_balance" = {
und = (
{
format = "<null>";
"safe_value" = 12;
value = 12;
}
);
};
"field_postal_code" = {
und = (
{
format = "<null>";
"safe_value" = 000000;
value = 000000;
}
);
};
"field_private_message_notify" = {
und = (
{
value = 1;
}
);
};
"field_profile_photo" = {
und = (
{
alt = "";
fid = 237;
"field_file_image_alt_text" = (
);
"field_file_image_title_text" = (
);
filemime = "image/jpeg";
filename = "1507092784.jpg";
filesize = 16084;
height = 296;
metadata = {
height = 296;
width = 300;
};
"rdf_mapping" = (
);
status = 1;
timestamp = 1507108254;
title = "";
type = image;
uid = 47;
uri = "public://stored/1507092784.jpg";
width = 300;
}
);
};
"field_property_type" = {
und = (
{
format = "<null>";
"safe_value" = House;
value = House;
}
);
};
"field_province" = {
und = (
{
format = "<null>";
"safe_value" = BC;
value = BC;
}
);
};
"field_special_skills" = {
und = (
{
format = "<null>";
"safe_value" = "Oral medication";
value = "Oral medication";
}
);
};
"field_star_rating" = {
und = (
{
format = "<null>";
"safe_value" = 1;
value = 1;
}
);
};
"field_street_address" = {
und = (
{
format = "<null>";
"safe_value" = "1325 Fake Street";
value = "1325 Fake Street";
}
);
};
"field_supervision" = {
und = (
{
format = "<null>";
"safe_value" = No;
value = No;
}
);
};
"field_userbio" = {
und = (
{
format = "<null>";
"safe_value" = "Hi my name is Brittany.";
value = "Hi my name is Brittany.";
}
);
};
language = "";
login = 1507320712;
mail = "brittany-b#shaw.ca";
name = Brittany;
picture = "<null>";
"rdf_mapping" = {
homepage = {
predicates = (
"foaf:page"
);
type = rel;
};
name = {
predicates = (
"foaf:name"
);
};
rdftype = (
"sioc:UserAccount"
);
};
roles = {
2 = "authenticated user";
};
signature = "";
"signature_format" = "filtered_html";
status = 1;
theme = "";
timezone = UTC;
uid = 47;
};
}

Answer 1

If the log output in your question is from logging [session user] then you need to first access the #"user" key.
NSString *address = [session user][#"user"][#"field_street_address"][#"und"][0][#"safe_value"];
BTW - for issues like this it really helps to break down the code:
NSDictionary *sessionUser = [session user];
NSDictionary *user = sessionUser[#"user"];
NSDicitonary *streetAddr = user[#"field_street_address"];
// etc.
Then you can see where you start getting nil and look at the previous results to determine where things are going wrong.