iOS文件上传

文件上传的步骤

//先创建一个request
NSURL *url = [NSURL URLWithString:@""];
NSMutableURLRequest *request = [NSMutableURLRequest requestWithURL:url];
[request setHTTPMethod:@"POST"];

1.设置请求头
*目的：告诉服务器请求体里面的内容并非普通参数，而是包含了文件参数
NSString *boundary = @"UploadBoundary";//设置请求体参数的分隔符（请求体分隔符必须在此前面加上两个-）
NSString *contentType = [NSString stringWithFormat:@"multipart/form-data; boundary=%@",boundary];
[request setValue:contentType forHTTPHeaderField:@"Content-Type"];

2.设置请求体
*作用：存放参数（文件参数和非文件参数）
1>非文件参数
[body appendData:[[NSString stringWithFormat:@"--%@\r\n",boundary] dataUsingEncoding:NSUTF8StringEncoding]];
[body appendData:[@"Content-Disposision: form-data: name=\"参数名\"\r\n" dataUsingEncoding:NSUTF8StringEncoding]];

[body appendData:[@"\r\n" dataUsingEncoding:NSUTF8StringEncoding]];
[body appendData:[@"参数值" dataUsingEncoding:NSUTF8StringEncoding]];
[body appendData:[@"\r\n" dataUsingEncoding:NSUTF8StringEncoding]];

2>文件参数
[body appendData:[[NSString stringWithFormat:@"--%@\r\n",boundary] dataUsingEncoding:NSUTF8StringEncoding]];
[body appendData:[@"Content-Disposition: form-data; name=\"参数名\"; filename=\"文件名\"\r\n" dataUsingEncoding:NSUTF8StringEncoding]];
[body appendData:[@"Content-Type: 文件类型\r\n" dataUsingEncoding:NSUTF8StringEncoding]];

[body appendData:[@"\r\n" dataUsingEncoding:NSUTF8StringEncoding]];
[body appendData:[NSData dataWithContentsOfFile:@""]];
[body appendData:[@"\r\n" dataUsingEncoding:NSUTF8StringEncoding]];

3>结尾标记
*作用：告诉请求体参数已拼接完成
[body appendData:[[NSString stringWithFormat:@"--%@--\r\n",boundary] dataUsingEncoding:NSUTF8StringEncoding]];

request.HTTPBody = body;
request设置完毕后，就可以发送请求了
[NSURLConnection sendAsynchronousRequest:request queue:[NSOperationQueue mainQueue] completionHandler:^(NSURLResponse * _Nullable response, NSData * _Nullable data, NSError * _Nullable connectionError) {
    //这里就和普通请求一样了
}];

使用NSURLConnection上传文件例子

/**
 上传文件

 @param url 地址
 @param fileName 上传到服务器的文件名称
 @param fileData 文件数据
 @param mimeType 文件类型
 @param params 非文件参数
 */
- (void)uploadWithUrl:(NSString *)url fileName:(NSString *)fileName fileData:(NSData *)fileData mimeType:(NSString *)mimeType params:(NSDictionary *)params{
    NSMutableURLRequest *request = [NSMutableURLRequest requestWithURL:[NSURL URLWithString:url]];
    [request setHTTPMethod:@"POST"];

    //设置请求头
    NSString *boundary = @"UploadBoundary";
    NSString *contentType = [NSString stringWithFormat:@"multipart/form-data; boundary=%@",boundary];
    [request setValue:contentType forHTTPHeaderField:@"Content-Type"];
    
    //设置请求体
    NSMutableData *body = [NSMutableData data];
    //非文件参数
    [params enumerateKeysAndObjectsUsingBlock:^(id  _Nonnull key, id  _Nonnull obj, BOOL * _Nonnull stop) {
        [body appendData:[[NSString stringWithFormat:@"--%@\r\n",boundary] dataUsingEncoding:NSUTF8StringEncoding]];
        NSString *disposision = [NSString stringWithFormat:@"Content-Disposision: form-data: name=\"%@\"\r\n",key];
        [body appendData:[disposision dataUsingEncoding:NSUTF8StringEncoding]];
        
        [body appendData:[@"\r\n" dataUsingEncoding:NSUTF8StringEncoding]];
        [body appendData:[[obj description] dataUsingEncoding:NSUTF8StringEncoding]];
        [body appendData:[@"\r\n" dataUsingEncoding:NSUTF8StringEncoding]];
    }];
    //文件参数
    [body appendData:[[NSString stringWithFormat:@"--%@\r\n",boundary] dataUsingEncoding:NSUTF8StringEncoding]];
    [body appendData:[[NSString stringWithFormat:@"Content-Disposition: form-data; name=\"file\"; filename=\"%@\"\r\n",fileName] dataUsingEncoding:NSUTF8StringEncoding]];
    [body appendData:[[NSString stringWithFormat:@"Content-Type: %@\r\n",mimeType] dataUsingEncoding:NSUTF8StringEncoding]];
    
    [body appendData:[@"\r\n" dataUsingEncoding:NSUTF8StringEncoding]];
    [body appendData:fileData];
    [body appendData:[@"\r\n" dataUsingEncoding:NSUTF8StringEncoding]];
    
    //结果标记
    [body appendData:[[NSString stringWithFormat:@"--%@--\r\n",boundary] dataUsingEncoding:NSUTF8StringEncoding]];
    request.HTTPBody = body;
    
    [NSURLConnection sendAsynchronousRequest:request queue:[NSOperationQueue mainQueue] completionHandler:^(NSURLResponse * _Nullable response, NSData * _Nullable data, NSError * _Nullable connectionError) {
        
    }];
}

使用AFN框架上传图片例子

NSString *urlString = @"";
AFHTTPRequestOperationManager *mgr = [AFHTTPRequestOperationManager manager];
//普通参数
NSMutableDictionary *params = [NSMutableDictionary dictionary];
[params setObject:@"张三" forKey:@"username"];
[mgr POST:urlString parameters:params constructingBodyWithBlock:^(id<AFMultipartFormData> formData) {
    NSData *imageData = UIImagePNGRepresentation([UIImage imageNamed:@""]);   
     /**
     拼接文件参数

     @fileData : 要上传的文件数据
     @name : 后台定义文件的参数名
     @fileName ： 上传到服务器的文件名称
     @mimeType : 上传的文件类型
   */
    [formData appendPartWithFileData:imageData name:@"file" fileName:@"text.png" mimeType:@"image/png"];
} success:^(AFHTTPRequestOperation *operation, id responseObject) {
        
} failure:^(AFHTTPRequestOperation *operation, NSError *error) {
        
}];

获取文件的MIMEType

/**
 获取文件的MIMEType

 @param url 文件路径
 @return 文件MIMEType
 */
- (NSString *)MIMEType:(NSURL *)url{
    NSURLRequest *request = [NSURLRequest requestWithURL:url];
    NSURLResponse *response = nil;
    [NSURLConnection sendSynchronousRequest:request returningResponse:&response error:nil];
    return response.MIMEType;
}

有时候项目需要要一次上传多张图片，可以将图片压缩成一个zip包，然后上传这样的方式来处理。文件压缩和解压工具SSZipArchive