我可以创建一个NSURL引用内存中的NSData？ [英] Can I create an NSURL that refers to in-memory NSData?

问题描述

的文档NSURL 说明：

NSURL对象表示一个可能包含
远程服务器上资源的位置，
磁盘上的本地文件的路径，或者甚至 任意编码数据。 >

An NSURL object represents a URL that can potentially contain the location of a resource on a remote server, the path of a local file on disk, or even an arbitrary piece of encoded data.

我有一个内存中的数据块，我想要一个库，想通过<$ c加载资源$ c> NSURL 。当然，我可以先把这个 NSData 写入一个临时文件，然后创建一个文件：// NSURL ，但我更喜欢让URL直接指向我已经在内存中存在的缓冲区。

I have a blob of in-memory data that I'd like to hand to a library that wants to load a resource via an NSURL. Sure, I can first write this NSData to a temp file and then create a file:// NSURL from that, but I'd prefer to have the URL point directly to the buffer that I already have present in memory.

上面引用的文档似乎暗示这是可能的，但我找不到任何提示如何完成它。

The docs quoted above seem to suggest this is possible, but I can't find any hint of how to accomplish it. Am I missing something?

推荐答案

NSURL 支持数据：//网址计划（ RFC 2397 ）。

此计划允许您以

NSURL supports the data:// URL-Scheme (RFC 2397).
This scheme allows you to build URLs in the form of

data://data:MIME-Type;base64,<data>

一个可行的Cocoa例子是：

A working Cocoa example would be:

NSImage* img = [NSImage imageNamed:@"img"];
NSData* imgData = [img TIFFRepresentation];
NSString* dataFormatString = @"data:image/png;base64,%@";
NSString* dataString = [NSString stringWithFormat:dataFormatString, [imgData base64EncodedStringWithOptions:0]];
NSURL* dataURL = [NSURL URLWithString:dataString];

由于base64编码的性质，使用数据URL传递大型二进制blob可能有点低效。

Passing around large binary blobs with data URLs might be a bit inefficient due to the nature of base64 encoding.

您还可以实施自定义 NSURLProtocol ，专门处理您的数据。
Apple有一些示例代码，使用自定义协议传递图像对象：https://developer.apple.com/library/mac/samplecode/SpecialPictureProtocol/Introduction/Intro.html#//apple_ref/doc/uid/DTS10003816

You could also implement a custom NSURLProtocol that specifically deals with your data. Apple has some sample code that uses a custom protocol to pass around image objects: https://developer.apple.com/library/mac/samplecode/SpecialPictureProtocol/Introduction/Intro.html#//apple_ref/doc/uid/DTS10003816

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