Capturing customer feedback with a device log on iOS

FeedbackViewController.m

#import <UIKit/UIKit.h>
#import <MessageUI/MessageUI.h>
#include <asl.h>

@interface FeedbackViewController : UIViewController <MFMailComposeViewControllerDelegate>

@property (nonatomic, strong) IBOutlet UITextView *textView;
@property (nonatomic, strong) NSString *feedbackType;

@end

@implementation FeedbackViewController

- (void)sendMail
{
    if ([MFMailComposeViewController canSendMail])
    {
        MFMailComposeViewController *mailer = [[MFMailComposeViewController alloc] init];
        mailer.mailComposeDelegate = self;
        
        [mailer setSubject:[@"AppName - " stringByAppendingString:self.feedbackType]];

        NSArray *toRecipients = @[@"support@yourapp.com"];
        [mailer setToRecipients:toRecipients];
        
        // Generate body
        NSString *appShortVersion = [[NSBundle mainBundle] objectForInfoDictionaryKey:@"CFBundleShortVersionString"];
        NSString *appVersion = [[NSBundle mainBundle] objectForInfoDictionaryKey:@"CFBundleVersion"];
        NSString *emailBody = [NSString stringWithFormat:@"%@\n\nVersion: %@ (%@)", self.textView.text, appShortVersion, appVersion];
        
        [mailer setMessageBody:emailBody isHTML:NO];

#if !TARGET_IPHONE_SIMULATOR
        [mailer addAttachmentData:[self getConsoleLog] mimeType:@"text/plain" fileName:@"application.log"];
#endif

        [self presentViewController:mailer animated:YES completion:^{}];
    }
    else
    {
        UIAlertView *alert = [[UIAlertView alloc] initWithTitle:@"Mail is unavailable"
                                                        message:@"Check your device is connected to the Internet and you have set up a Mail account in the Settings app."
                                                       delegate:nil
                                              cancelButtonTitle:@"OK"
                                              otherButtonTitles:nil];
        [alert show];
    }
}

- (void)mailComposeController:(MFMailComposeViewController*)controller didFinishWithResult:(MFMailComposeResult)result error:(NSError*)error
{
    switch (result)
    {
        case MFMailComposeResultCancelled:
            NSLog(@"Mail cancelled: you cancelled the operation and no email message was queued.");
            break;
        case MFMailComposeResultSaved:
            NSLog(@"Mail saved: you saved the email message in the drafts folder.");
            break;
        case MFMailComposeResultSent:
            NSLog(@"Mail send: the email message is queued in the outbox. It is ready to send.");
            break;
        case MFMailComposeResultFailed:
            NSLog(@"Mail failed: the email message was not saved or queued, possibly due to an error.");
            break;
        default:
            NSLog(@"Mail not sent.");
            break;
    }
    
    // Remove the mail view
    [self dismissViewControllerAnimated:YES completion:^{
        if (result == MFMailComposeResultSent)
            [self.navigationController popViewControllerAnimated:YES];
    }];
}

// Get the app's console log
- (NSData *)getConsoleLog
{
    // Create an Apple System Log query.
    aslmsg query = asl_new(ASL_TYPE_QUERY);
    aslresponse response = asl_search(NULL, query);
    
    // Iterate through the query responses and assemble them into a log string.
    NSString* logString = [NSString new];
    
    aslmsg message;
    if (floor(NSFoundationVersionNumber) <= NSFoundationVersionNumber_iOS_7_1)
    {
#pragma GCC diagnostic push
#pragma GCC diagnostic ignored "-Wdeprecated-declarations"
        while ((message = aslresponse_next(response)) != NULL) {
            @autoreleasepool {
                NSMutableDictionary *tmpDict = [NSMutableDictionary dictionary];
                const char *key, *val;
                
                // Get all the key/value pairs from the response message. We don't really need them all, but it's a little simpler to just get them all in C.
                for (int i = 0; (key = asl_key(message, i)) != NULL; i++) {
                    NSString *keyString = [NSString stringWithUTF8String:(char *)key];
                    
                    val = asl_get(message, key);
                    
                    NSString *string = val ? [NSString stringWithUTF8String:val] : @"";
                    [tmpDict setObject:string forKey:keyString];
                }
                
                // Get the key/value pairs that we want and append them to the log string.
                NSDate* date = [NSDate dateWithTimeIntervalSince1970:((NSNumber*)tmpDict[@"Time"]).doubleValue];
                NSString* dateString = [NSDateFormatter localizedStringFromDate:date dateStyle:NSDateFormatterShortStyle timeStyle:NSDateFormatterLongStyle];
                logString = [logString stringByAppendingFormat:@"%@ %@\n",dateString, tmpDict[@"Message"]];
            }
        }
        aslresponse_free(response);
#pragma GCC diagnostic pop
    }
    else {
        while ((message = asl_next(response)) != NULL) {
            @autoreleasepool {
                NSMutableDictionary *tmpDict = [NSMutableDictionary dictionary];
                const char *key, *val;
                
                // Get all the key/value pairs from the response message. We don't really need them all, but it's a little simpler to just get them all in C.
                for (int i = 0; (key = asl_key(message, i)) != NULL; i++) {
                    NSString *keyString = [NSString stringWithUTF8String:(char *)key];
                    
                    val = asl_get(message, key);
                    
                    NSString *string = val ? [NSString stringWithUTF8String:val] : @"";
                    [tmpDict setObject:string forKey:keyString];
                }
                
                // Get the key/value pairs that we want and append them to the log string.
                NSDate* date = [NSDate dateWithTimeIntervalSince1970:((NSNumber*)tmpDict[@"Time"]).doubleValue];
                NSString* dateString = [NSDateFormatter localizedStringFromDate:date dateStyle:NSDateFormatterShortStyle timeStyle:NSDateFormatterLongStyle];
                logString = [logString stringByAppendingFormat:@"%@ %@\n",dateString, tmpDict[@"Message"]];
            }
        }
        asl_free(response);
    }
    
    return [logString dataUsingEncoding:NSUTF8StringEncoding];
}

@end