ios HTTP 状态代码 411 - 需要长度
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HTTP Status Code 411 - Length Required
提问by WantToKnow
I try to get data from server. I use NSURLConnectionDelegate, NSURLConnectionDataDelegate. There is code (Objective - C).
我尝试从服务器获取数据。我使用 NSURLConnectionDelegate、NSURLConnectionDataDelegate。有代码（目标-C）。
-(void)sendRequest
{
NSURL* url = [[NSURL alloc] initWithString:@"http://SomeServer"];
NSMutableURLRequest* request = [[NSMutableURLRequest alloc] init];
NSString* reqBody = [NSString stringWithFormat:@"<tag>Content</tag>"];
NSData* reqData = [reqBody dataUsingEncoding:NSUTF8StringEncoding];
NSInputStream* stream = [NSInputStream inputStreamWithData:reqData];
[request setURL:url];
[request setHTTPBodyStream:stream];
[request setHTTPMethod:@"POST"];
self.wpData = [[NSMutableData alloc] init];
NSURLConnection* conection = [[NSURLConnection alloc] initWithRequest:request delegate:self];
[conection start];
}
- (void)connection:(NSURLConnection *)connection didReceiveResponse:(NSURLResponse *)response {
[self.wpData setLength:0];
}
- (void)connection:(NSURLConnection *)connection didReceiveData:(NSData *)d {
NSString* str = [[NSString alloc] initWithData:d encoding:NSUTF8StringEncoding];
NSLog(@"RESPONSE DATA: %@",str);
[self.wpData appendData:d];
}
But I get "411 - Length Required" when I use
但是当我使用时我得到“411 - Length Required”
[request setHTTPBodyStream:stream];
and "HASH (someAddress)" when I use
和“HASH (someAddress)”当我使用
[request setHTTPBody:reqData];
I tried
我试过
[request setHTTPBodyStream:stream];
NSString *postLength = [NSString stringWithFormat:@"%d", [reqData length]];
[request setValue:postLength forHTTPHeaderField:@"Content-Length"];
but again "HASH (someAdddress)"
但还是“哈希（某个地址）”
What have I done wrong? Sorry for my English. Thanks :)
我做错了什么？对不起我的英语不好。谢谢 ：）
回答by CouchDeveloper
What have I done wrong?
我做错了什么？
Nothing.
没有。
HTTP Status Code 411 (Length Required) is sent by the server as a response when it refuses to accept a message without a content-length header, for whatever reason.
HTTP 状态代码 411（需要长度）由服务器发送作为响应，当它拒绝接受没有内容长度标头的消息时，无论出于何种原因。
A server simply may or may not accept a content without a Content-Length header.
服务器可能会也可能不会接受没有 Content-Length 标头的内容。
When you set an NSInputStreamobject as request body via property HTTPBodyStreamfor the request, NSURLConnectioncannot evaluate the length of the body itself anymore. (there is no property lengthfor a stream). Hence, NSURLConnectionuses a certain "transfer mode", namely "chunked transfer encoding". This transfer mode shouldsucceed to transmit any body and it does not require a Content-Legth header (actually mustnot contain one). Alas, the server simply does not accept this type of transfer.
当您NSInputStream通过请求的属性将对象设置为请求正文时HTTPBodyStream，NSURLConnection无法再评估正文本身的长度。（length流没有属性）。因此，NSURLConnection使用了某种“传输模式”，即“分块传输编码”。这种传递方式应该成功传输任何机构，它不需要内容Legth头（其实一定不能包含一个）。唉，服务器根本不接受这种类型的传输。
See also: Chunked transfer encoding(wiki).
另请参阅：分块传输编码(wiki)。
To solve the issue on the client side:
要解决客户端的问题：
Determine the length of the body yourself (if possible) and set a "Content-Length" header field for the request. If this input stream has been created from a file or from a
NSDataobject, the length can be easily determined. But be sure to set the exact same length as the actual stream content in bytes.Don't use a
NSInputStream, but use aNSDataobject as body and set it via propertyHTTPBody. When you set the body as aNSDataobject,NSURLConnectioncan determine the content length itself, and it will automatically add a Content-Length header with the correct length, unless you set it yourself in the request.
自己确定正文的长度（如果可能）并为请求设置“Content-Length”标头字段。如果此输入流是从文件或
NSData对象创建的，则可以轻松确定其长度。但一定要设置与实际流内容完全相同的长度（以字节为单位）。不要使用 a
NSInputStream，而是使用一个NSData对象作为主体并通过 property 设置它HTTPBody。当你将body设置为NSData对象时，NSURLConnection可以自己确定内容长度，它会自动添加一个长度正确的Content-Length头，除非你自己在请求中设置。
