[Author: iwade]

Add gtm_dictionaryWithHttpArgumentsString to NSDictionary+URLArguments.

R=thomasvl
APPROVED=thomasvl
DELTA=73  (72 added, 0 deleted, 1 changed)

3 files changed, 71 insertions, 1 deletions

diff --git a/Foundation/GTMNSDictionary+URLArguments.h b/Foundation/GTMNSDictionary+URLArguments.h
index 4bc896d..b094411 100644
--- a/Foundation/GTMNSDictionary+URLArguments.h
+++ b/Foundation/GTMNSDictionary+URLArguments.h
@@ -21,8 +21,14 @@
 /// Utility for building a URL or POST argument string.
 @interface NSDictionary (GTMNSDictionaryURLArgumentsAdditions)
 
+/// Returns a dictionary of the decoded key-value pairs in a http arguments
+/// string of the form key1=value1&key2=value2&...&keyN=valueN.
+/// Keys and values will be unescaped automatically.
+/// Only the first value for a repeated key is returned.
++ (NSDictionary *)gtm_dictionaryWithHttpArgumentsString:(NSString *)argString;
+
 /// Gets a string representation of the dictionary in the form
-/// key1=value1&key2&value2&...&keyN=valueN, suitable for use as either
+/// key1=value1&key2=value2&...&keyN=valueN, suitable for use as either
 /// URL arguments (after a '?') or POST body. Keys and values will be escaped
 /// automatically, so should be unescaped in the dictionary.
 - (NSString *)gtm_httpArgumentsString;
diff --git a/Foundation/GTMNSDictionary+URLArguments.m b/Foundation/GTMNSDictionary+URLArguments.m
index 89610e4..4799b2d 100644
--- a/Foundation/GTMNSDictionary+URLArguments.m
+++ b/Foundation/GTMNSDictionary+URLArguments.m
@@ -24,6 +24,37 @@
 @implementation NSDictionary (GTMNSDictionaryURLArgumentsAdditions)
 
 GTM_METHOD_CHECK(NSString, gtm_stringByEscapingForURLArgument);
+GTM_METHOD_CHECK(NSString, gtm_stringByUnescapingFromURLArgument);
+
++ (NSDictionary *)gtm_dictionaryWithHttpArgumentsString:(NSString *)argString {
+  NSMutableDictionary* ret = [NSMutableDictionary dictionary];
+  NSArray* components = [argString componentsSeparatedByString:@"&"];
+  NSString* component;
+  // Use reverse order so that the first occurrence of a key replaces
+  // those subsequent.
+  GTM_FOREACH_ENUMEREE(component, [components reverseObjectEnumerator]) {
+    if ([component length] == 0)
+      continue;
+    NSRange pos = [component rangeOfString:@"="];
+    NSString *key;
+    NSString *val;
+    if (pos.location == NSNotFound) {
+      key = [component gtm_stringByUnescapingFromURLArgument];
+      val = @"";
+    } else {
+      key = [[component substringToIndex:pos.location]
+             gtm_stringByUnescapingFromURLArgument];
+      val = [[component substringFromIndex:pos.location + pos.length]
+             gtm_stringByUnescapingFromURLArgument];
+    }
+    // gtm_stringByUnescapingFromURLArgument returns nil on invalid UTF8
+    // and NSMutableDictionary raises an exception when passed nil values.
+    if (!key) key = @"";
+    if (!val) val = @"";
+    [ret setObject:val forKey:key];
+  }
+  return ret;
+}
 
 - (NSString *)gtm_httpArgumentsString {
   NSMutableArray* arguments = [NSMutableArray arrayWithCapacity:[self count]];
diff --git a/Foundation/GTMNSDictionary+URLArgumentsTest.m b/Foundation/GTMNSDictionary+URLArgumentsTest.m
index f01519e..8ec9520 100644
--- a/Foundation/GTMNSDictionary+URLArgumentsTest.m
+++ b/Foundation/GTMNSDictionary+URLArgumentsTest.m
@@ -25,6 +25,39 @@
 
 @implementation GTMNSDictionary_URLArgumentsTest
 
+- (void)testFromArgumentsString {
+  STAssertEqualObjects([NSDictionary gtm_dictionaryWithHttpArgumentsString:@""],
+                       [NSDictionary dictionary],
+                       @"- empty arguments string should give an empty dictionary");
+  STAssertEqualObjects([NSDictionary gtm_dictionaryWithHttpArgumentsString:@"a"],
+                       [NSDictionary dictionaryWithObject:@"" forKey:@"a"],
+                       @"- missing '=' should result in an empty string value");
+  STAssertEqualObjects([NSDictionary gtm_dictionaryWithHttpArgumentsString:@"a="],
+                       [NSDictionary dictionaryWithObject:@"" forKey:@"a"],
+                       @"- no value");
+  STAssertEqualObjects([NSDictionary gtm_dictionaryWithHttpArgumentsString:@"&a=1"],
+                       [NSDictionary dictionaryWithObject:@"1" forKey:@"a"],
+                       @"- empty segment should be skipped");
+  STAssertEqualObjects([NSDictionary gtm_dictionaryWithHttpArgumentsString:@"abc=123"],
+                       [NSDictionary dictionaryWithObject:@"123" forKey:@"abc"],
+                       @"- simple one-pair dictionary should work");
+  STAssertEqualObjects([NSDictionary gtm_dictionaryWithHttpArgumentsString:@"a=1&a=2&a=3"],
+                       [NSDictionary dictionaryWithObject:@"1" forKey:@"a"],
+                       @"- only first occurrence of a key is returned");
+  NSString* complex = @"a%2Bb=specialkey&complex=1%2B1%21%3D3%20%26%202%2A6%2F3%3D4&c";
+  NSDictionary* result = [NSDictionary dictionaryWithObjectsAndKeys:
+                          @"1+1!=3 & 2*6/3=4", @"complex",
+                                @"specialkey", @"a+b",
+                                          @"", @"c",
+                                               nil];
+  STAssertEqualObjects([NSDictionary gtm_dictionaryWithHttpArgumentsString:complex],
+                       result,
+                       @"- keys and values should be unescaped correctly");
+  STAssertEqualObjects([NSDictionary gtm_dictionaryWithHttpArgumentsString:@"a=%FC"],
+                       [NSDictionary dictionaryWithObject:@"" forKey:@"a"],
+                       @"- invalid UTF8 characters result in an empty value, not a crash");
+}
+
 - (void)testArgumentsString {
   STAssertEqualObjects([[NSDictionary dictionary] gtm_httpArgumentsString], @"",
                        @"- empty dictionary should give an empty string");