使用预签名URL将文件上传到AWS S3的代码有什么问题？

Question

我想使用预先签名的URL将文件从iOS App上传到AWS S3存储桶.URL是正确的,因为它在命令行上使用curl.

curl -v -k --upload-file FILENAME "https://MYBUCKET.amazonaws.com:443/KEYNAME?Signature=...&Expires=1391691489&AWSAccessKeyId=..."

使用以下Objective-C代码......

- (void)upload:(NSString *)url fileData:(NSData *)fileData
{
    NSMutableURLRequest *request = [[NSMutableURLRequest alloc] init];
    [request setURL:[NSURL URLWithString:url]];
    [request setHTTPMethod:@"PUT"];
    [request setHTTPBody:fileData];
    [request setValue:[NSString stringWithFormat:@"%d", [fileData length]] forHTTPHeaderField:@"Content-Length"];
    [request setValue:@"audio/mpeg" forHTTPHeaderField:@"Content-Type"];
    [request setValue:@"public-read" forHTTPHeaderField:@"x-amz-acl"];
    [request setValue:@"iPhone-OS/6.0 fr_FR NE" forHTTPHeaderField:@"User-Agent"];

    _connection = [NSURLConnection connectionWithRequest:request delegate:self];
    [_connection start];
}

...我收到此错误:

Error Domain=NSURLErrorDomain Code=-1001 "The request timed out." UserInfo=0x9c49560 {NSErrorFailingURLStringKey=https://MYBUCKET.s3.amazonaws.com:443/KEYNAME?Signature=...&Expires=1391703958&AWSAccessKeyId=..., NSErrorFailingURLKey=https://MYBUCKET.amazonaws.com:443/KEYNAME?Signature=...&Expires=1391703958&AWSAccessKeyId=..., NSLocalizedDescription=The request timed out., NSUnderlyingError=0x9c48c80 "The request timed out."}

我使用WireShark查看是否有任何流量,并且有很多流量.

我不知道我的代码有什么问题.似乎文件传输没有正确终止.

Answer 1

我自己解决了这个问题 该Content-Type标题是罪魁祸首.在完全绝望中,我用一个非常小的文本文件测试了我的代码,并从S3获得了403作为HTTP状态代码.没有超时.这样的进步.我还收到了一条非常丰富的错误消息:

<?xml version="1.0" encoding="UTF-8"?>
<Error>
    <Code>SignatureDoesNotMatch</Code><Message>The request signature we calculated does not match the signature you provided. Check your key and signing method.</Message><StringToSignBytes>...</StringToSignBytes><RequestId>...</RequestId><HostId>...</HostId><SignatureProvided>...</SignatureProvided>
    <StringToSign>PUT

    text/plain
    1391784394
    KEYNAME</StringToSign>
    <AWSAccessKeyId>...</AWSAccessKeyId>
</Error>

显然,text/plain如果从客户端提供内容类型字符串(在这种情况下),则它是在字符串到符号中预期的.不要问我为什么这会导致大(5.5MB？)文件超时.我希望这能为其他人节省几个小时的生命.

最简单的解决方法是删除该行

[request setValue:@"..." forHTTPHeaderField:@"Content-Type"];

如果您在创建预签名URL时知道内容类型,则可以将字符串添加到字符串到符号.