我正在使用此功能使用
JSON将图像上传到服务器.为此,我首先将图像转换为NSData,然后使用Base64转换为NSString.当图像不是很大时,该方法可以正常工作,但是当我尝试上传2Mb图像时,它会崩溃.
问题是,即使调用didReceiveResponse方法以及返回(null)的didReceiveData,服务器也不会接收我的图像.起初我认为这是一个超时问题,但即使将其设置为1000.0它仍然不起作用.任何的想法？谢谢你的时间！
这是我目前的代码：
- (void) imageRequest {
NSMutableURLRequest *request = [NSMutableURLRequest requestWithURL:[NSURL URLWithString:@"http://www.myurltouploadimage.com/services/v1/upload.json"]];
NSString *docDir = [NSSearchPathForDirectoriesInDomains(NSDocumentDirectory,NSUserDomainMask,YES) objectAtIndex:0];
NSString *path = [NSString stringWithFormat:@"%@/design%i.png",docDir,designNum];
NSLog(@"%@",path);
NSData *imageData = UIImagePNGRepresentation([UIImage imageWithContentsOfFile:path]);
[Base64 initialize];
NSString *imageString = [Base64 encode:imageData];
NSArray *keys = [NSArray arrayWithObjects:@"design",nil];
NSArray *objects = [NSArray arrayWithObjects:imageString,nil];
NSDictionary *jsonDictionary = [NSDictionary dictionaryWithObjects:objects forKeys:keys];
NSError *error;
NSData *jsonData = [NSJSONSerialization dataWithJSONObject:jsonDictionary options:kNilOptions error:&error];
[request setHTTPMethod:@"POST"];
[request setValue:[NSString stringWithFormat:@"%d",[jsonData length]] forHTTPHeaderField:@"Content-Length"];
[request setValue:@"application/json" forHTTPHeaderField:@"Accept"];
[request setValue:@"application/json" forHTTPHeaderField:@"Content-Type"];
[request setHTTPBody:jsonData];
[[NSURLConnection alloc] initWithRequest:request delegate:self];
NSLog(@"Image uploaded");
}
- (void) connection:(NSURLConnection *)connection didReceiveResponse:(NSURLResponse *)response {
NSLog(@"didReceiveResponse");
}
- (void) connection:(NSURLConnection *)connection didReceiveData:(NSData *)data {
NSLog(@"%@",[NSJSONSerialization JSONObjectWithData:data options:kNilOptions error:nil]);
}
解决方法
我最终决定将Base64图像上传到较小的子串中.为了做到这一点,并且因为我需要许多NSURLConnections,我创建了一个名为TagConnection的子类,它为每个连接提供一个标记,这样它们之间就不会产生混淆.
然后我在MyViewController中创建了一个TagConnection属性,目的是从任何函数访问它.正如您所看到的,有-startAsyncLoad：withTag：分配和插入TagConnection的函数和-connection：didReceiveData：当我从服务器收到响应时删除它的那个.
参考-uploadImage函数,首先,它将图像转换为字符串,然后将其拆分并将块放在JSON请求中.它被调用,直到变量offset大于字符串长度,这意味着已经上传了所有块.
您还可以通过每次检查服务器响应并仅在返回成功时调用-uploadImage函数来证明每个块已成功上载.
我希望这是一个有用的答案.谢谢.
TagConnection.h
@interface TagConnection : NSURLConnection {
NSString *tag;
}
@property (strong,nonatomic) NSString *tag;
- (id)initWithRequest:(NSURLRequest *)request delegate:(id)delegate startImmediately:(BOOL)startImmediately tag:(NSString*)tag;
@end
TagConnection.m
#import "TagConnection.h"
@implementation TagConnection
@synthesize tag;
- (id)initWithRequest:(NSURLRequest *)request delegate:(id)delegate startImmediately:(BOOL)startImmediately tag:(NSString*)tag {
self = [super initWithRequest:request delegate:delegate startImmediately:startImmediately];
if (self) {
self.tag = tag;
}
return self;
}
- (void)dealloc {
[tag release];
[super dealloc];
}
@end
MyViewController.h
#import "TagConnection.h" @interface MyViewController : UIViewController @property (strong,nonatomic) TagConnection *conn;
MyViewController.m
#import "MyViewController.h"
@interface MyViewController ()
@end
@synthesize conn;
bool stopSending = NO;
int chunkNum = 1;
int offset = 0;
- (IBAction) uploadImageButton:(id)sender {
[self uploadImage];
}
- (void) startAsyncLoad:(NSMutableURLRequest *)request withTag:(NSString *)tag {
self.conn = [[[TagConnection alloc] initWithRequest:request delegate:self startImmediately:YES tag:tag] autorelease];
}
- (void) uploadImage {
NSMutableURLRequest *request = [NSMutableURLRequest requestWithURL:[NSURL URLWithString:@"http://www.mywebpage.com/upload.json"] cachePolicy:NSURLRequestUseProtocolCachePolicy timeoutInterval:1000.0];
NSString *docDir = [NSSearchPathForDirectoriesInDomains(NSDocumentDirectory,YES) objectAtIndex:0];
NSString *path = [NSString stringWithFormat:@"%@/design%i.png",designNum];
NSLog(@"%@",path);
NSData *imageData = UIImagePNGRepresentation([UIImage imageWithContentsOfFile:path]);
[Base64 initialize];
NSString *imageString = [Base64 encode:imageData];
NSUInteger length = [imageString length];
NSUInteger chunkSize = 1000;
NSUInteger thisChunkSize = length - offset > chunkSize ? chunkSize : length - offset;
NSString *chunk = [imageString substringWithRange:NSMakeRange(offset,thisChunkSize)];
offset += thisChunkSize;
NSArray *keys = [NSArray arrayWithObjects:@"design",@"design_id",@"fragment_id",nil];
NSArray *objects = [NSArray arrayWithObjects:chunk,[NSString stringWithFormat:@"%i",chunkNum],nil];
NSDictionary *jsonDictionary = [NSDictionary dictionaryWithObjects:objects forKeys:keys];
NSError *error;
NSData *jsonData = [NSJSONSerialization dataWithJSONObject:jsonDictionary options:kNilOptions error:&error];
[request setHTTPMethod:@"POST"];
[request setValue:[NSString stringWithFormat:@"%d",[jsonData length]] forHTTPHeaderField:@"Content-Length"];
[request setValue:@"application/json" forHTTPHeaderField:@"Accept"];
[request setValue:@"application/json" forHTTPHeaderField:@"Content-Type"];
[request setHTTPBody:jsonData];
[self startAsyncLoad:request withTag:[NSString stringWithFormat:@"tag%i",chunkNum]];
if (offset > length) {
stopSending = YES;
}
}
- (void) connection:(NSURLConnection *)connection didReceiveData:(NSData *)data {
NSError *error;
NSArray *responseData = [NSJSONSerialization JSONObjectWithData:data options:kNilOptions error:&error];
if (!responseData) {
NSLog(@"Error parsing JSON: %@",error);
} else {
if (stopSending == NO) {
chunkNum++;
[self.conn cancel];
self.conn = nil;
[self uploadImage];
} else {
NSLog(@"---------Image sent---------");
}
}
}
@end
