将多个图像上传到服务器时，应用程序占用大量内存

Question

In my app there is need to upload multiple image to server. when we going to upload image to server ONE BY ONE or ALL IMAGE once's.

The basic problem is .

1. app consuming a lot memory when uploading image to server.
2. memory that was consuming by app not release after uploading image.

here is code for uploading image to server. using simple AFNetwortking.

-(void) uploadImageToServerOneByOne:(int)count andImage:(UIImage*)img         {
NSMutableDictionary *parem_dict;

if (parem_dict == nil) {
    parem_dict = [[NSMutableDictionary alloc]init];
}

[parem_dict setObject:@"jpeg" forKey:@"extension"];
[parem_dict setObject:@706 forKey:@"order_id"];
[parem_dict setObject:@"gallary" forKey:@"image_type"];
[parem_dict setObject:@(count+1) forKey:@"count"];
[parem_dict setObject:@(1) forKey:@"product_id"];
[parem_dict setObject:@"SNAPBOOK" forKey:@"type"];

manager.requestSerializer.timeoutInterval = 1200 ;
manager.responseSerializer.acceptableContentTypes = [NSSet setWithObject:@"text/plain"];
[manager POST:@"http://52.42.247.73:8080/anaventures/image/upload" parameters:parem_dict constructingBodyWithBlock:^(id<AFMultipartFormData>  _Nonnull formData) {

    [formData appendPartWithFileData:UIImageJPEGRepresentation(img, 0.5) name:@"file" fileName:@"filename.jpg" mimeType:@"image/jpeg"];

    [parem_dict removeAllObjects];
    formData = nil;

} progress:^(NSProgress * _Nonnull uploadProgress) {
    NSLog(@"%f",uploadProgress.fractionCompleted);

} success:^(NSURLSessionDataTask * _Nonnull task, id  _Nullable responseObject) {
    [MyLoader hideLoadingView];
    if (count + 1 < imageArray.count) {

        [self uploadImageToServerOneByOne:count +1 andImage:imageArray[count+1]];

    }else{

        [MyLoader hideLoadingView];

        NSLog(@" image successfully uploaded  -------- ohhhhhhhhooooooooooo!");

    }
    NSLog(@"success");

} failure:^(NSURLSessionDataTask * _Nullable task, NSError * _Nonnull error) {

    [MyLoader hideLoadingView];
    NSLog(@"fail%@", error.localizedDescription);
}];
}

Thanks in advance

Answer 1

Your problem is you did not use async methods to upload images.

I show you a upload image method and example:

Util method:
+ (void)uploadImage:(UIImage *)image withUrl:(NSString *)uploadUrl withBlock:(void (^)(NSString *))returnUrl {

UIImage *img = image;

//UIImage *com_img = [Util compressImage:img toMaxFileSize:25 * 1000];  // max is 250kb   // 50 *1000 :333759

UIImage *com_img_before = [Util imageCompressForWidth:img targetWidth:80];

UIImage *com_img = [Util compressImage:com_img_before toMaxFileSize:25 * 1000];

//NSData *dataObj = UIImagePNGRepresentation(com_img);

NSData *dataObj;
if (UIImagePNGRepresentation(com_img) == nil) {

    dataObj = UIImageJPEGRepresentation(com_img, 1);

} else {

    dataObj = UIImagePNGRepresentation(com_img);
}



NSDictionary * param1 = @{
                          @"id":@1,
                          @"imgFile":dataObj
                          };
AFHTTPSessionManager * session = [AFHTTPSessionManager manager];
session.responseSerializer.acceptableContentTypes = [NSSet setWithObjects:@"application/json",@"application/xml",@"text/json",@"text/javascript",@"text/html",@"text/plain",@"multipart/form-data",nil];

//url
NSString *url = [NSString stringWithFormat:@"%@%@", BASE_URL, uploadUrl]; // uploadHeader  uploadImages

[session POST:url parameters:param1 constructingBodyWithBlock:^(id<AFMultipartFormData>  _Nonnull formData) {

    UIImage *img = image; // response
    NSData *data = UIImagePNGRepresentation(img);

    // schoolListItem@2x
    [formData appendPartWithFileData:data name:@"imgFile" fileName:@"imgFile.png"mimeType:@"image/png"];
} success:^(NSURLSessionDataTask * _Nonnull task, id  _Nonnull responseObject) {

    NSLog(@"success+%@", responseObject);
    NSString *return_url = [NSString stringWithFormat:@"%@",responseObject[@"data"]]; //
    // pass data by block
    returnUrl(return_url);



} failure:^(NSURLSessionDataTask * _Nonnull task, NSError * _Nonnull error) {
    NSLog(@"fail");
}];


}


 USAGE:

 [MBProgressHUD showHUDAddedTo:self.view animated:YES];
        __block int comemntCount = 0;

        NSString *url = @"prescription/uploadImages"; // the uplad url

        static dispatch_once_t onceToken;
        static dispatch_semaphore_t semaphore;  // sema 
        static dispatch_queue_t queue;

        dispatch_once(&onceToken, ^{
            semaphore = dispatch_semaphore_create(1);
            //queue = dispatch_queue_create("com.MyApp.task", NULL);
            queue = dispatch_get_global_queue(DISPATCH_QUEUE_PRIORITY_DEFAULT, 0);  
        });


        for (int i = 0; i < _selectedAssets.count; i ++) {  //_photosChooseArr

            dispatch_async(queue, ^{

                dispatch_semaphore_wait(semaphore,  DISPATCH_TIME_FOREVER);
                [Util uploadImage:_selectedPhotos[i] withUrl:url withBlock:^(NSString *returnUrl) {

                    if (i == 0) {
                        files = returnUrl;
                        comemntCount ++;
                        if (comemntCount == _selectedAssets.count) {
                            [MBProgressHUD hideHUDForView:self.view animated:YES];
                            [self doUploadMessageWithFiles:files];

                        }
                    }else { 

                        files = [files stringByAppendingString:[NSString stringWithFormat:@",%@", returnUrl]];
                        comemntCount ++;

                        if (comemntCount == _selectedAssets.count) {
                            [MBProgressHUD hideHUDForView:self.view animated:YES];
                            [self doUploadMessageWithFiles:files];
                            NSLog(@"i = %d, returnUrl = %@, files = %@", i, returnUrl, files);
                        }
                    }

                    dispatch_semaphore_signal(semaphore);

                }];

            });

        }



        /* 3 min after hide the hud  */
        dispatch_after(dispatch_time(DISPATCH_TIME_NOW, (int64_t)(180.0 * NSEC_PER_SEC)), dispatch_get_main_queue(), ^{
            // 60s after close the hud
            [MBProgressHUD hideHUDForView:self.view animated:YES];
        });

This is my method to upload image array, and you can copy to your project to research, and I hope can help you.