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编辑：我需要将文件从 iPhone 异步上传到 Python 服务器端进程。我想异步执行请求，以便在它工作时显示一个忙碌的动画。

请求需要包含用户名、密码和文件作为“multipart/form-data”。

我可以使用 NSURLConnection 使其同步工作，代码如下所示：

-(void) uploadDatabase{

Database *databasePath = [[Database alloc] init];
NSString *targetPath = [databasePath getPathToDatabaseInDirectory];

NSData *dbData = [NSData dataWithContentsOfFile:targetPath];
NSString *url = @"http://mydomain.com/api/upload/";
//NSString *username = [[NSUserDefaults standardUserDefaults] stringForKey:USERNAME];
NSString *username = @"user";
NSString *password = @"pass";
NSMutableURLRequest *request = [self createRequestForUrl:url withUsername:username andPassword:password andData:dbData];

NSURLResponse *response;
NSError *error;

NSData *result = [NSURLConnection sendSynchronousRequest:request returningResponse:&response error:&error];

NSString *stringResult = [[NSString alloc] initWithData:result encoding:NSUTF8StringEncoding];

NSLog(@"**server info %@", stringResult);}

// 请求构造

    -(NSMutableURLRequest*) createRequestForUrl: (NSString*)urlString withUsername:(NSString*)username andPassword:(NSString*)password andData:(NSData*)dbData
    {NSURL *url = [NSURL URLWithString:urlString];
NSMutableURLRequest *request = [NSMutableURLRequest requestWithURL:url cachePolicy:NSURLRequestReloadIgnoringCacheData timeoutInterval:60.0];
[request setHTTPMethod:@"POST"];

NSString *boundary = @"BOUNDARY_STRING";
NSString *contentType = [NSString stringWithFormat:@"multipart/form-data; boundary=%@", boundary];
[request addValue:contentType forHTTPHeaderField:@"Content-Type"];

NSMutableData *body = [NSMutableData data];

if(dbData != NULL)
{
    //only send these methods when transferring data as well as username and password
    [body appendData:[[NSString stringWithFormat:@"\r\n--%@\r\n", boundary] dataUsingEncoding:NSUTF8StringEncoding]];
    [body appendData:[[NSString stringWithFormat:@"Content-Disposition: form-data; name=\"file\"; filename=\"dbfile\"\r\n"] dataUsingEncoding:NSUTF8StringEncoding]];
    [body appendData:[@"Content-Type: application/octet-stream\r\n\r\n" dataUsingEncoding:NSUTF8StringEncoding]];
    [body appendData:[NSData dataWithData:dbData]];
}

[body appendData:[[NSString stringWithFormat:@"\r\n--%@\r\n", boundary] dataUsingEncoding:NSUTF8StringEncoding]];
[body appendData:[[NSString stringWithFormat:@"Content-Disposition: form-data; name=\"username\"\r\n\r\n%@", username] dataUsingEncoding:NSUTF8StringEncoding]];

[body appendData:[[NSString stringWithFormat:@"\r\n--%@\r\n", boundary] dataUsingEncoding:NSUTF8StringEncoding]];
[body appendData:[[NSString stringWithFormat:@"Content-Disposition: form-data; name=\"password\"\r\n\r\n%@", password] dataUsingEncoding:NSUTF8StringEncoding]];

[body appendData:[[NSString stringWithFormat:@"\r\n--%@\r\n", boundary] dataUsingEncoding:NSUTF8StringEncoding]];

[request setHTTPBody:body];

return request;}

但是，当我尝试使用 NSURLSession 异步执行此操作时，它似乎无法正常工作。NSURLSession 的代码如下所示：

    -(void)uploadDatabase{
    Database *databasePath = [[Database alloc] init];
    NSString *targetPath = [databasePath getPathToDatabaseInDirectory];
    NSURL *phonedbURL = [NSURL URLWithString:targetPath];

    NSString *url = @"http://mydomain.com/api/upload/";
    NSString *username = @"user";
    NSString *password = @"pass";
    NSMutableURLRequest *request = [self createRequestForUrl:url withUsername:username andPassword:password andData:NULL];

NSURLSessionConfiguration *defaultConfigObject = [NSURLSessionConfiguration defaultSessionConfiguration];

self.uploadSession = [NSURLSession sessionWithConfiguration:defaultConfigObject delegate:self delegateQueue:Nil];
NSLog(@"the url = %@",url);
NSURLSessionUploadTask *uploadTask = [self.uploadSession uploadTaskWithRequest:request fromFile:phonedbURL];

[uploadTask resume];}

我正在努力看看我在做什么不同，但似乎这应该有效。

使用 NSURLSession 是执行异步请求的正确方法吗？而且我是 NSURLSession 的新手，所以我必须为 NSURLSession 请求而不是 NSURLConnection 更改我的 NSURLMutableRequest 吗？

提前感谢您的帮助！

4

1 回答 1

25

你是对的，如果你只是想让你的请求异步，你应该退休sendSynchronousRequest。虽然我们曾经推荐过sendAsynchronousRequest有效的 iOS 9，但NSURLConnection它已被正式弃用，应该受到支持NSURLSession。

一旦开始使用NSURLSession，您可能会发现自己被它所吸引。例如，可以使用[NSURLSessionConfiguration backgroundSessionConfiguration:]，然后即使在应用程序进入后台后也有上传进度。（您必须编写一些委托方法，所以为了简单起见，我一直在下面进行简单的前台上传。）这只是您的业务需求的问题，抵消了新NSURLSession功能与它所带来的 iOS 7+ 限制。

顺便说一句，如果不参考AFNetworking ，任何关于 iOS/MacOS 中网络请求的对话都可能是不完整的。它极大地简化了这些多部分请求的创建，绝对值得研究。他们也有NSURLSession支持（但我没有使用他们的会话包装器，所以不能说话）。但AFNetworking无疑值得你考虑。sendSynchronousRequest您可以享受基于委托的 API 的一些丰富性（例如进度更新、可取消的请求、操作之间的依赖关系等），提供比便利方法（如委托方法本身。

无论如何，如果您真的对如何使用 进行上传感兴趣NSURLSession，请参见下文。

如果您想通过 上传NSURLSession，则思想略有转变，即将请求（及其标头）的配置与请求NSMutableURLRequest正文的创建（您现在在实例化过程中指定）分开NSURLSessionUploadTask）。您现在指定为上传任务的一部分的请求正文可以是NSData、文件或流（我在NSData下面使用 a ，因为我们正在构建一个多部分请求）：

NSMutableURLRequest *request = [NSMutableURLRequest requestWithURL:url];
[request setHTTPMethod:@"POST"];
NSString *boundary = [self boundaryString];
[request addValue:[NSString stringWithFormat:@"multipart/form-data; boundary=%@", boundary] forHTTPHeaderField:@"Content-Type"];

NSURLSessionConfiguration *configuration = [NSURLSessionConfiguration defaultSessionConfiguration];
NSURLSession *session = [NSURLSession sessionWithConfiguration:configuration];

NSData *fileData = [NSData dataWithContentsOfFile:path];
NSData *data = [self createBodyWithBoundary:boundary username:@"rob" password:@"password" data:fileData filename:[path lastPathComponent]];

NSURLSessionUploadTask *task = [session uploadTaskWithRequest:request fromData:data completionHandler:^(NSData *data, NSURLResponse *response, NSError *error) {
    NSAssert(!error, @"%s: uploadTaskWithRequest error: %@", __FUNCTION__, error);

    // parse and interpret the response `NSData` however is appropriate for your app
}];
[task resume];

发送的创建NSData很像您现有的代码：

- (NSData *) createBodyWithBoundary:(NSString *)boundary username:(NSString*)username password:(NSString*)password data:(NSData*)data filename:(NSString *)filename
{
    NSMutableData *body = [NSMutableData data];

    if (data) {
        //only send these methods when transferring data as well as username and password
        [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\r\n", [self mimeTypeForPath:filename]] dataUsingEncoding:NSUTF8StringEncoding]];
        [body appendData:data];
        [body appendData:[@"\r\n" dataUsingEncoding:NSUTF8StringEncoding]];
    }

    [body appendData:[[NSString stringWithFormat:@"--%@\r\n", boundary] dataUsingEncoding:NSUTF8StringEncoding]];
    [body appendData:[[NSString stringWithFormat:@"Content-Disposition: form-data; name=\"username\"\r\n\r\n%@\r\n", username] dataUsingEncoding:NSUTF8StringEncoding]];

    [body appendData:[[NSString stringWithFormat:@"--%@\r\n", boundary] dataUsingEncoding:NSUTF8StringEncoding]];
    [body appendData:[[NSString stringWithFormat:@"Content-Disposition: form-data; name=\"password\"\r\n\r\n%@\r\n", password] dataUsingEncoding:NSUTF8StringEncoding]];

    [body appendData:[[NSString stringWithFormat:@"--%@--\r\n", boundary] dataUsingEncoding:NSUTF8StringEncoding]];

    return body;
}

您硬编码了边界和 mime 类型，这很好，但上面恰好使用了以下方法：

- (NSString *)boundaryString
{
    NSString *uuidStr = [[NSUUID UUID] UUIDString];

    // If you need to support iOS versions prior to 6, you can use
    // Core Foundation UUID functions to generate boundary string
    //
    // adapted from http://developer.apple.com/library/ios/#samplecode/SimpleURLConnections
    //
    // NSString  *uuidStr;
    //
    // CFUUIDRef uuid = CFUUIDCreate(NULL);
    // assert(uuid != NULL);
    // 
    // NSString  *uuidStr = CFBridgingRelease(CFUUIDCreateString(NULL, uuid));
    // assert(uuidStr != NULL);
    // 
    // CFRelease(uuid);

    return [NSString stringWithFormat:@"Boundary-%@", uuidStr];
}

- (NSString *)mimeTypeForPath:(NSString *)path
{
    // get a mime type for an extension using MobileCoreServices.framework

    CFStringRef extension = (__bridge CFStringRef)[path pathExtension];
    CFStringRef UTI = UTTypeCreatePreferredIdentifierForTag(kUTTagClassFilenameExtension, extension, NULL);
    assert(UTI != NULL);

    NSString *mimetype = CFBridgingRelease(UTTypeCopyPreferredTagWithClass(UTI, kUTTagClassMIMEType));
    assert(mimetype != NULL);

    CFRelease(UTI);

    return mimetype;
}
于 2014-01-03T04:35:27.757 回答