From 68eb634027c2d5af23c8f8e0a772433cbf709ea2 Mon Sep 17 00:00:00 2001
From: Mattt Thompson <m@mattt.me>
Date: Fri, 2 Mar 2012 11:18:20 -0800
Subject: [PATCH] Adding AFContentTypesFromHTTPHeader()

---
 AFNetworking/AFHTTPRequestOperation.h |  5 +++++
 AFNetworking/AFHTTPRequestOperation.m | 25 +++++++++++++++++++++++++
 2 files changed, 30 insertions(+)

diff --git a/AFNetworking/AFHTTPRequestOperation.h b/AFNetworking/AFHTTPRequestOperation.h
index e836ce5..95260f3 100644
--- a/AFNetworking/AFHTTPRequestOperation.h
+++ b/AFNetworking/AFHTTPRequestOperation.h
@@ -23,6 +23,11 @@
 #import <Foundation/Foundation.h>
 #import "AFURLConnectionOperation.h"
 
+/**
+ Returns a set of MIME types detected in an HTTP `Accept` or `Content-Type` header.
+ */
+extern NSSet * AFContentTypesFromHTTPHeader(NSString *string);
+
 /**
  `AFHTTPRequestOperation` is a subclass of `AFURLConnectionOperation` for requests using the HTTP or HTTPS protocols. It encapsulates the concept of acceptable status codes and content types, which determine the success or failure of a request.
  */
diff --git a/AFNetworking/AFHTTPRequestOperation.m b/AFNetworking/AFHTTPRequestOperation.m
index aa9d612..00e8c67 100644
--- a/AFNetworking/AFHTTPRequestOperation.m
+++ b/AFNetworking/AFHTTPRequestOperation.m
@@ -24,6 +24,31 @@
 
 #import <objc/runtime.h>
 
+NSSet * AFContentTypesFromHTTPHeader(NSString *string) {
+    static NSCharacterSet *_skippedCharacterSet = nil;
+    static dispatch_once_t onceToken;
+    dispatch_once(&onceToken, ^{
+        _skippedCharacterSet = [NSCharacterSet characterSetWithCharactersInString:@" ,"];
+    });
+    
+    NSScanner *scanner = [NSScanner scannerWithString:string];
+    scanner.charactersToBeSkipped = _skippedCharacterSet;
+    
+    NSMutableSet *mutableContentTypes = [NSMutableSet set];
+    while (![scanner isAtEnd]) {
+        NSString *contentType = nil;
+        if ([scanner scanUpToString:@";" intoString:&contentType]) {
+            [scanner scanUpToString:@"," intoString:nil];
+        }
+        
+        if (contentType) {
+            [mutableContentTypes addObject:contentType];
+        }
+    }
+    
+    return [NSSet setWithSet:mutableContentTypes];
+}
+
 static void AFSwizzleClassMethodWithClassAndSelectorUsingBlock(Class klass, SEL selector, void *block) {
     Method originalMethod = class_getClassMethod(klass, selector);
     IMP implementation = imp_implementationWithBlock(block);