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The docs for NSURL state that:
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.
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.
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?
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An NSURL object is composed of two parts—a potentially nil base URL and a string that is resolved relative to the base URL. An NSURL object is considered absolute if its string part is fully resolved without a base; all other URLs are considered relative.
They are identical in usage, Apple has chosen to drop the NeXTSTEP prefix in support of using foundation with Swift on multiple platforms like iOS, Android, and Linux. from Apple: "The Swift overlay to the Foundation framework provides the URL structure, which bridges to the NSURL class.
A static byte buffer that bridges to Data ; use NSData when you need reference semantics or other Foundation-specific behavior. iOS 2.0+ iPadOS 2.0+ macOS 10.0+ Mac Catalyst 13.0+ tvOS 9.0+ watchOS 2.0+
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> 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]; Passing around large binary blobs with data URLs might be a bit inefficient due to the nature of base64 encoding.
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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