原始的方式实现文件上传 & AFNetworking文件上传

原始方式文件上传的步骤：
     1、创建POST请求
      NSURL *url = [NSURL URLWithString:@"文件上传到服务器的Url"];
      NSMutableURLRequest *request = [NSMutableURLRequest requestWithURL:url];
      request.HTTPMethod = @"POST";
    2、设置请求头(告诉告诉服务器,这是一个文件上传的请求)
        ①非文件参数(普通的用户名账户和密码等参数）
        --本次文件上传的标识字符串\r\n
        Content-Disposition: form-data; name="参数名"\r\n
        \r\n
        参数值
         \r\n
        ②文件参数（上传文件的二进制数据、若上传多个文件时，多次使用该格式）
        --本次文件上传的标识字符串\r\n
         Content-Disposition: form-data; name="参数名"; filename="文件名"\r\n
         Content-Type: 文件的MIMEType\r\n
         \r\n
         文件数据
         \r\n

        ③添加结束标记，必须遵守格式
        --本次文件上传的标识字符串--\r\n

示例程序：
#define XMGBoundary @"520it"
#define XMGEncode(string) [string dataUsingEncoding:NSUTF8StringEncoding]
#define XMGNewLine [@"\r\n" dataUsingEncoding:NSUTF8StringEncoding]

#import "ViewController.h"

@interface ViewController ()

@end

@implementation ViewController

- (void)viewDidLoad {
    [super viewDidLoad];
    
    // 创建请求
    NSURL *url = [NSURL URLWithString:@"http://120.25.226.186:32812/upload"];
    NSMutableURLRequest *request = [NSMutableURLRequest requestWithURL:url];
    request.HTTPMethod = @"POST";
    
    // 设置请求头(告诉告诉服务器,这是一个文件上传的请求)
    [request setValue:[NSString stringWithFormat:@"multipart/form-data; boundary=%@", XMGBoundary] forHTTPHeaderField:@"Content-Type"];
    
    // 设置请求体
    NSMutableData *body = [NSMutableData data];
    
    // 文件参数
    /*
     --分割线\r\n
     Content-Disposition: form-data; name="参数名"; filename="文件名"\r\n
     Content-Type: 文件的MIMEType\r\n
     \r\n
     文件数据
     \r\n
     */
    // 分割线
    [body appendData:XMGEncode(@"--")];
    [body appendData:XMGEncode(XMGBoundary)];
    [body appendData:XMGNewLine];
    
    // 文件参数名
    [body appendData:XMGEncode([NSString stringWithFormat:@"Content-Disposition: form-data; name=\"file\"; filename=\"test.png\""])];
    [body appendData:XMGNewLine];
    
    // 文件的类型
    [body appendData:XMGEncode([NSString stringWithFormat:@"Content-Type: image/png"])];
    [body appendData:XMGNewLine];
    
    // 文件数据
    [body appendData:XMGNewLine];
//    UIImageJPEGRepresentation(<#UIImage *image#>, <#CGFloat compressionQuality#>)
    UIImage *image = [UIImage imageNamed:@"placeholder"];
    [body appendData:UIImagePNGRepresentation(image)];
//    [body appendData:[NSData dataWithContentsOfFile:@"/Users/xiaomage/Desktop/test.png"]];
    [body appendData:XMGNewLine];
    
    // 非文件参数
    /*
     --分割线\r\n
     Content-Disposition: form-data; name="参数名"\r\n
     \r\n
     参数值
     \r\n
     */
    // 分割线
    [body appendData:XMGEncode(@"--")];
    [body appendData:XMGEncode(XMGBoundary)];
    [body appendData:XMGNewLine];
    
    // 参数名
    [body appendData:XMGEncode([NSString stringWithFormat:@"Content-Disposition: form-data; name=\"username\""])];
    [body appendData:XMGNewLine];
    
    // 参数值
    [body appendData:XMGNewLine];
    [body appendData:XMGEncode(@"jack")];
    [body appendData:XMGNewLine];
    
    // 结束标记
    /*
     --分割线--\r\n
     */
    [body appendData:XMGEncode(@"--")];
    [body appendData:XMGEncode(XMGBoundary)];
    [body appendData:XMGEncode(@"--")];
    [body appendData:XMGNewLine];
    
    request.HTTPBody = body;
    
    [NSURLConnection sendAsynchronousRequest:request queue:[NSOperationQueue mainQueue] completionHandler:^(NSURLResponse *response, NSData *data, NSError *connectionError) {
        NSLog(@"%@", [NSJSONSerialization JSONObjectWithData:data options:kNilOptions error:nil]);
    }];
}

@end

    2、使用AFN提供的POST方法最便捷
    ①上传单个文件
    AFHTTPSessionManager *mgr = [AFHTTPSessionManager manager];
    
    [mgr POST:@"http://120.25.226.186:32812/upload" parameters:@{@"username" : @"123"}
        constructingBodyWithBlock:^(id formData) {
        // 在这个block中设置需要上传的文件
//            NSData *data = [NSData dataWithContentsOfFile:@"/Users/xiaomage/Desktop/placeholder.png"];
//            [formData appendPartWithFileData:data name:@"file" fileName:@"test.png" mimeType:@"image/png"];
            
//            [formData appendPartWithFileURL:[NSURL fileURLWithPath:@"/Users/xiaomage/Desktop/placeholder.png"] name:@"file" fileName:@"xxx.png" mimeType:@"image/png" error:nil];
    
            [formData appendPartWithFileURL:[NSURL fileURLWithPath:@"/Users/xiaomage/Desktop/placeholder.png"] name:@"file" error:nil];
    } success:^(NSURLSessionDataTask *task, id responseObject) {
        NSLog(@"-------%@", responseObject);
    } failure:^(NSURLSessionDataTask *task, NSError *error) {
        
    }];
   ②上传多个文件文件
AFHTTPSessionManager *sharedManager1 = [[AFHTTPSessionManager alloc]init];
sharedManager1.requestSerializer = [AFHTTPRequestSerializer serializer];
sharedManager1.responseSerializer.acceptableContentTypes = [NSSet setWithObjects:@"application/json", @"text/json", @"text/javascript", @"text/html", @"text/plain",nil];
sharedManager1.requestSerializer.timeoutInterval =20;
[sharedManager1.requestSerializer setValue:@"application/json" forHTTPHeaderField:@"Accept"];
[sharedManager1.requestSerializer setValue:@"text/html; charset=utf-8" forHTTPHeaderField:@"Content-Type"];
    NSDictionary *dic = @{@"param.token":_token};
[sharedManager1 POST:kUploadFile parameters:dic constructingBodyWithBlock:^(id  _Nonnull formData) {
        for (int i = 0; i < fileUpload.count; i ++) {
                NSData *data = UIImageJPEGRepresentation(fileUpload[i], 0.3);
                NSDateFormatter *formatter = [[NSDateFormatter alloc] init];
                // 设置时间格式
                formatter.dateFormat = @"yyyyMMddHHmmss";
                NSString *str = [formatter stringFromDate:[NSDate date]];
                NSString *fileName = [NSString stringWithFormat:@"%@-%@.jpeg", str,[NSString stringWithFormat:@"%d",i]];
                [formData appendPartWithFileData:data name:@"fileUpload" fileName:fileName mimeType:@"image/jpeg"];     
        }
    } success:^(NSURLSessionDataTask * _Nonnull task, id  _Nonnull responseObject) {
        success(task,responseObject);
    } failure:^(NSURLSessionDataTask * _Nonnull task, NSError * _Nonnull error) {
        fail(task,error);
    }];

3、NSURLSessionConfiguration实现文件上传
    NSMutableURLRequest *request = [NSMutableURLRequest requestWithURL:[NSURL URLWithString:@"http://120.25.226.186:32812/upload"]];
    request.HTTPMethod = @"POST";
    
    // 设置请求头(告诉服务器,这是一个文件上传的请求)
    [request setValue:[NSString stringWithFormat:@"multipart/form-data; boundary=%@", XMGBoundary] forHTTPHeaderField:@"Content-Type"];
    
    // 设置请求体
    NSMutableData *body = [NSMutableData data];
    
    // 文件参数
    // 分割线
    [body appendData:XMGEncode(@"--")];
    [body appendData:XMGEncode(XMGBoundary)];
    [body appendData:XMGNewLine];
    
    // 文件参数名
    [body appendData:XMGEncode([NSString stringWithFormat:@"Content-Disposition: form-data; name=\"file\"; filename=\"test.png\""])];
    [body appendData:XMGNewLine];
    
    // 文件的类型
    [body appendData:XMGEncode([NSString stringWithFormat:@"Content-Type: image/png"])];
    [body appendData:XMGNewLine];
    
    // 文件数据
    [body appendData:XMGNewLine];
    [body appendData:[NSData dataWithContentsOfFile:@"/Users/xiaomage/Desktop/test.png"]];
    [body appendData:XMGNewLine];
    
    // 结束标记
    /*
     --分割线--\r\n
     */
    [body appendData:XMGEncode(@"--")];
    [body appendData:XMGEncode(XMGBoundary)];
    [body appendData:XMGEncode(@"--")];
    [body appendData:XMGNewLine];
    
    [[self.session uploadTaskWithRequest:request fromData:body completionHandler:^(NSData *data, NSURLResponse *response, NSError *error) {
        NSLog(@"-------%@", [NSJSONSerialization JSONObjectWithData:data options:kNilOptions error:nil]);
    }] resume];

    4、使用AFN的uploadTaskWithRequest方法需要类似NSURLSessionConfiguration、原始上传数据 拼接请求体比较麻烦

      AFHTTPSessionManager *mgr = [AFHTTPSessionManager manager];
    NSURLRequest *request = [NSURLRequest requestWithURL:@""];
    NSMutableData *body = [NSMutableData data];

    [mgr uploadTaskWithRequest:request fromData:body progress:<#(NSProgress *__autoreleasing *)#> completionHandler:^(NSURLResponse *response, id responseObject, NSError *error) {
        NSLog(@"-------%@", [NSJSONSerialization JSONObjectWithData:data options:kNilOptions error:nil]);
    }];