使用AFNetworking上传图片和视频，支持多张图片上传。以下是AFNetworking用于上传文件的关键函数。

代码执行有问题, 转载来只是为了清晰看懂灵活运用写法
转自(不确定为原版): http://www.jianshu.com/p/c169cc8f94ce

part1

/*
 @paramdata图片或视频二进制数据
 @paramname 对应服务器的字段名
 @paramfileName 文件名，后缀要跟文件类型一致，不能为空
 @parammimeType 文件类型 举例image/pngvideo/quicktime
 */
- (void)uploadFileWithMediaData:(NSMutableArray *)mediaDatas
                            url:(NSString *)url
                         params:(id)params{
    AFHTTPRequestOperationManager *manager = [AFHTTPRequestOperationManager manager];
    manager.responseSerializer.acceptableContentTypes = [NSSet setWithObjects:@"text/html",
                                                         @"text/plain",
                                                         @"application/json",nil];
    AFHTTPRequestOperation *operation = [manager POST:url
                                           parameters:nil
                            constructingBodyWithBlock:^(id formData) {
                                if (mediaDatas.count > 0) {
                                    NSObject *firstObj = [mediaDatas objectAtIndexSafe:0];
                                    if ([firstObj isKindOfClass:[UIImage class]]) {
                                        // 图片
                                        for(NSInteger i=0; i<mediaDatas.count;i++){
                                            UIImage *eachImg = [mediaDatas objectAtIndexSafe:i];
                                            //NSData *eachImgData = UIImagePNGRepresentation(eachImg);
                                            NSData *eachImgData = UIImageJPEGRepresentation(eachImg, 0.5);
                                            [formData appendPartWithFileData:eachImgData name:@"file" fileName:[NSString stringWithFormat:@"img%ld.png", i+1] mimeType:@"image/png"];
                                        }
                                    }else if([firstObj isKindOfClass:[ALAsset class]]){
                                        // 视频
                                        ALAsset *asset = [mediaDatas objectAtIndexSafe:0];
                                        NSLog(@"asset=%@, representation=%@, url=%@", asset, [asset defaultRepresentation], [asset defaultRepresentation].url);
                                        if (asset != nil) {
                                            NSArray *documentPaths= NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES);
                                            NSString *docuPath = [documentPaths objectAtIndex:0];
                                            NSString *videoPath= [docuPath stringByAppendingPathComponent:[NSString stringWithFormat:@"%d.mov", 0]];    // 这里直接强制写一个即可，之前计划是用i++来区分不明视频
                                            NSURL *url = [NSURL fileURLWithPath:videoPath];
                                            NSError *theErro = nil;
                                            BOOL exportResult = [asset exportDataToURL:url error:&theErro];
                                            NSLog(@"exportResult=%@", exportResult?@"YES":@"NO");
                                            NSData *videoData = [NSData dataWithContentsOfURL:url];
                                            [formData appendPartWithFileData:videoData name:@"file" fileName:@"video1.mov" mimeType:@"video/quicktime"];
                                        }
                                    }
                                }
                            } success:^(AFHTTPRequestOperation *operation, id responseObject) {
                                //成功后回调
                            } failure:^(AFHTTPRequestOperation *operation, NSError *error) {
                                //失败后回调
                            }];
    [operation setUploadProgressBlock:^(NSUInteger bytesWritten, long long totalBytesWritten, long long totalBytesExpectedToWrite) {
        //进度
        self.progressBlock(totalBytesWritten*1.0/totalBytesExpectedToWrite);
    }];
}

part2

//通过CTAssetsPickerController来选择手机相册中的视频文件的。然后通过生成一个视频文件名及地址，并通过一个写方法， 写到该路径下， 写文件如下。
#define BufferSize 10000
- (BOOL) exportDataToURL: (NSURL*) fileURL error: (NSError**) error{
    [[NSFileManager defaultManager] createFileAtPath:[fileURL path] contents:nil attributes:nil];
    NSFileHandle *handle = [NSFileHandle fileHandleForWritingToURL:fileURL error:error];
    if (!handle) {
        return NO;
    }
    ALAssetRepresentation *rep = [self defaultRepresentation];
    uint8_t *buffer = calloc(BufferSize, sizeof(*buffer));
    NSUInteger offset = 0, bytesRead = 0;
    do {
        @try {
            bytesRead = [rep getBytes:buffer fromOffset:offset length:BufferSize error:error];
            [handle writeData:[NSData dataWithBytesNoCopy:buffer length:bytesRead freeWhenDone:NO]];
            offset += bytesRead;
        } @catch (NSException *exception) {
            free(buffer);
            return NO;
        }
    } while (bytesRead > 0);
    free(buffer);
    return YES;
}