// LocalyticsUploader.m
// Copyright (C) 2009 Char Software Inc., DBA Localytics
//
// This code is provided under the Localytics Modified BSD License.
// A copy of this license has been distributed in a file called LICENSE
// with this source code.
//
// Please visit www.localytics.com for more information.
#import "LocalyticsUploader.h"
#import "LocalyticsSession.h"
#import "LocalyticsDatabase.h"
#import <zlib.h>
#define LOCALYTICS_URL @"http://analytics.localytics.com/api/v2/applications/%@/uploads"
static LocalyticsUploader *_sharedUploader = nil;
@interface LocalyticsUploader ()
- (void)finishUpload;
- (NSData *)gzipDeflatedDataWithData:(NSData *)data;
- (void)logMessage:(NSString *)message;
@property (readwrite) BOOL isUploading;
@end
@implementation LocalyticsUploader
@synthesize isUploading = _isUploading;
#pragma mark - Singleton Class
+ (LocalyticsUploader *)sharedLocalyticsUploader {
@synchronized(self) {
if (_sharedUploader == nil) {
_sharedUploader = [[self alloc] init];
}
}
return _sharedUploader;
}
#pragma mark - Class Methods
- (void)uploaderWithApplicationKey:(NSString *)localyticsApplicationKey {
// Do nothing if already uploading.
if (self.isUploading == true)
{
[self logMessage:@"Upload already in progress. Aborting."];
return;
}
[self logMessage:@"Beginning upload process"];
self.isUploading = true;
// Prepare the data for upload. The upload could take a long time, so some effort has to be made to be sure that events
// which get written while the upload is taking place don't get lost or duplicated. To achieve this, the logic is:
// 1) Append every header row blob string and and those of its associated events to the upload string.
// 2) Deflate and upload the data.
// 3) On success, delete all blob headers and staged events. Events added while an upload is in process are not
// deleted because they are not associated a header (and cannot be until the upload completes).
// Step 1
NSAutoreleasePool *pool = [[NSAutoreleasePool alloc] init];
LocalyticsDatabase *db = [LocalyticsDatabase sharedLocalyticsDatabase];
NSString *blobString = [db uploadBlobString];
if ([blobString length] == 0) {
// There is nothing outstanding to upload.
[self logMessage:@"Abandoning upload. There are no new events."];
[pool drain];
[self finishUpload];
return;
}
NSData *requestData = [blobString dataUsingEncoding:NSUTF8StringEncoding];
NSString *myString = [[[NSString alloc] initWithData:requestData encoding:NSUTF8StringEncoding] autorelease];
[self logMessage:[NSString stringWithFormat:@"Uploading data (length: %u)", [myString length]]];
// Step 2
NSData *deflatedRequestData = [[self gzipDeflatedDataWithData:requestData] retain];
[pool drain];
NSString *apiUrlString = [NSString stringWithFormat:LOCALYTICS_URL, [localyticsApplicationKey stringByAddingPercentEscapesUsingEncoding:NSUTF8StringEncoding]];
NSMutableURLRequest *submitRequest = [NSMutableURLRequest requestWithURL:[NSURL URLWithString:apiUrlString]
cachePolicy:NSURLRequestReloadIgnoringCacheData
timeoutInterval:60.0];
[submitRequest setHTTPMethod:@"POST"];
[submitRequest setValue:@"application/x-gzip" forHTTPHeaderField:@"Content-Type"];
[submitRequest setValue:@"gzip" forHTTPHeaderField:@"Content-Encoding"];
[submitRequest setValue:[NSString stringWithFormat:@"%d", [deflatedRequestData length]] forHTTPHeaderField:@"Content-Length"];
[submitRequest setHTTPBody:deflatedRequestData];
[deflatedRequestData release];
// Perform synchronous upload in an async dispatch. This is necessary because the calling block will not persist to
// receive the response data.
dispatch_group_async([[LocalyticsSession sharedLocalyticsSession] criticalGroup], [[LocalyticsSession sharedLocalyticsSession] queue], ^{
@try {
NSURLResponse *response = nil;
NSError *responseError = nil;
[NSURLConnection sendSynchronousRequest:submitRequest returningResponse:&response error:&responseError];
NSInteger responseStatusCode = [(NSHTTPURLResponse *)response statusCode];
if (responseError) {
// On error, simply print the error and close the uploader. We have to assume the data was not transmited
// so it is not deleted. In the event that we accidently store data which was succesfully uploaded, the
// duplicate data will be ignored by the server when it is next uploaded.
[self logMessage:[NSString stringWithFormat:
@"Error Uploading. Code: %d, Description: %@",
[responseError code],
[responseError localizedDescription]]];
} else {
// Step 3
// While response status codes in the 5xx range leave upload rows intact, the default case is to delete.
if (responseStatusCode >= 500 && responseStatusCode < 600) {
[self logMessage:[NSString stringWithFormat:@"Upload failed with response status code %d", responseStatusCode]];
} else {
// Because only one instance of the uploader can be running at a time it should not be possible for
// new upload rows to appear so there is no fear of deleting data which has not yet been uploaded.
[self logMessage:[NSString stringWithFormat:@"Upload completed successfully. Response code %d", responseStatusCode]];
[[LocalyticsDatabase sharedLocalyticsDatabase] deleteUploadedData];
}
}
}
@catch (NSException * e) {}
[self finishUpload];
});
}
- (void)finishUpload
{
self.isUploading = false;
// Upload data has been deleted. Recover the disk space if necessary.
[[LocalyticsDatabase sharedLocalyticsDatabase] vacuumIfRequired];
}
/*!
@method gzipDeflatedDataWithData
@abstract Deflates the provided data using gzip at the default compression level (6). Complete NSData gzip category available on CocoaDev. http://www.cocoadev.com/index.pl?NSDataCategory.
@return the deflated data
*/
- (NSData *)gzipDeflatedDataWithData:(NSData *)data
{
if ([data length] == 0) return data;
z_stream strm;
strm.zalloc = Z_NULL;
strm.zfree = Z_NULL;
strm.opaque = Z_NULL;
strm.total_out = 0;
strm.next_in=(Bytef *)[data bytes];
strm.avail_in = [data length];
// Compresssion Levels:
// Z_NO_COMPRESSION
// Z_BEST_SPEED
// Z_BEST_COMPRESSION
// Z_DEFAULT_COMPRESSION
if (deflateInit2(&strm, Z_DEFAULT_COMPRESSION, Z_DEFLATED, (15+16), 8, Z_DEFAULT_STRATEGY) != Z_OK) return nil;
NSMutableData *compressed = [NSMutableData dataWithLength:16384]; // 16K chunks for expansion
do {
if (strm.total_out >= [compressed length])
[compressed increaseLengthBy: 16384];
strm.next_out = [compressed mutableBytes] + strm.total_out;
strm.avail_out = [compressed length] - strm.total_out;
deflate(&strm, Z_FINISH);
} while (strm.avail_out == 0);
deflateEnd(&strm);
[compressed setLength: strm.total_out];
return [NSData dataWithData:compressed];
}
/*!
@method logMessage
@abstract Logs a message with (localytics uploader) prepended to it
@param message The message to log
*/
- (void) logMessage:(NSString *)message {
if(DO_LOCALYTICS_LOGGING) {
NSLog(@"(localytics uploader) %s\n", [message UTF8String]);
}
}
#pragma mark - System Functions
+ (id)allocWithZone:(NSZone *)zone {
@synchronized(self) {
if (_sharedUploader == nil) {
_sharedUploader = [super allocWithZone:zone];
return _sharedUploader;
}
}
// returns nil on subsequent allocations
return nil;
}
- (id)copyWithZone:(NSZone *)zone {
return self;
}
- (id)retain {
return self;
}
- (unsigned)retainCount {
// maximum value of an unsigned int - prevents additional retains for the class
return UINT_MAX;
}
- (oneway void)release {
// ignore release commands
}
- (id)autorelease {
return self;
}
- (void)dealloc {
[_sharedUploader release];
[super dealloc];
}
@end