Encodes special characters in query params with percent encoding. (#35)

* Encodes special characters in query params with percent encoding.

* Abstracted out encode url into its own function and only creates the character set once.

* Intiantiate a mutable copy of the characterSet then store an immutable set. Per https://developer.apple.com/library/content/documentation/Cocoa/Conceptual/Strings/Articles/CharacterSets.html

* updating return logic for encodeUrlParam

* adds unit tests for the queryParamRewrite

* code review changes

Author: davidtruong

Iterable-iOS-SDK/IterableAPI.m

@@ -40,6 +40,7 @@ @implementation IterableAPI {
 // the API endpoint
 NSString * const endpoint = @"https://api.iterable.com/api/";
 
+NSCharacterSet* encodedCharacterSet = nil;
 
 //////////////////////////
 /// @name Internal methods
@@ -72,6 +73,13 @@ + (NSString *)pushServicePlatformToString:(PushServicePlatform)pushServicePlatfo
     return result;
 }
 
+- (NSCharacterSet *)getEncodedSubset
+{
+    NSMutableCharacterSet* workingSet = [[NSCharacterSet URLQueryAllowedCharacterSet] mutableCopy];
+    [workingSet removeCharactersInString:@"+"];
+    return [workingSet copy];
+}
+
 /**
  @method
  
@@ -99,19 +107,36 @@ - (NSURL *)getUrlForAction:(NSString *)action
 - (NSURL *)getUrlForGetAction:(NSString *)action withArgs:(NSDictionary *)args
 {
     NSString *urlCombined = [NSString stringWithFormat:@"%@%@?api_key=%@", endpoint, action, self.apiKey];
-    //updated this to take in a dictionary are parse values
-    
 
     for (NSString* paramKey in args) {
         NSString* paramValue = args[paramKey];
 
-        NSString *params = [NSString stringWithFormat:@"&%@=%@", paramKey, paramValue];
+        NSString *params = [NSString stringWithFormat:@"&%@=%@", paramKey, [self encodeURLParam:paramValue]];
         urlCombined = [urlCombined stringByAppendingString:params];
     }
 
     return [NSURL URLWithString:urlCombined];
 }
 
+/**
+ @method
+ 
+ @abstract Percent encodes the url query parameters
+ 
+ @param paramValue The value to encode
+ 
+ @return an `NSString` containing the encoded value
+ */
+- (NSString *)encodeURLParam:(NSString *)paramValue
+{
+    if ([paramValue isKindOfClass:[NSString class]])
+    {
+        return [paramValue stringByAddingPercentEncodingWithAllowedCharacters:encodedCharacterSet];
+    } else {
+        return paramValue;
+    }
+}
+
 /**
  @method
  
@@ -329,6 +354,8 @@ - (instancetype)createSession:(NSDictionary *)launchOptions useCustomLaunchOptio
     // if it gets instantiated again that's fine; we don't need to reconfigure the session, just keep using the old singleton
     [self createUrlSession];
 
+    encodedCharacterSet = [self getEncodedSubset];
+    
     // Automatically try to track a pushOpen
     if (launchOptions) {
         if (useCustomLaunchOptions) {

Iterable-iOS-SDKTests/IterableAPITests.m

@@ -17,6 +17,8 @@ @interface IterableAPI (Test)
 + (NSString *)pushServicePlatformToString:(PushServicePlatform)pushServicePlatform;
 + (NSString *)dictToJson:(NSDictionary *)dict;
 + (NSString *)userInterfaceIdiomEnumToString:(UIUserInterfaceIdiom)idiom;
+
+- (NSString *)encodeURLParam:(NSString *)paramValue;
 @end
 
 @interface IterableAPITests : XCTestCase
@@ -184,4 +186,40 @@ - (void)testUniversalDeepLinkHttps {
     }];
 }
 
+- (void)testURLQueryParamRewrite {
+    [IterableAPI sharedInstanceWithApiKey:@"" andEmail:@"" launchOptions:nil];
+    
+    NSCharacterSet* set = [NSCharacterSet URLQueryAllowedCharacterSet];
+    
+    NSMutableString* strSet =[NSMutableString string];
+    for (int plane = 0; plane <= 16; plane++) {
+        if ([set hasMemberInPlane:plane]) {
+            UTF32Char c;
+            for (c = plane << 16; c < (plane+1) << 16; c++) {
+                if ([set longCharacterIsMember:c]) {
+                    UTF32Char c1 = OSSwapHostToLittleInt32(c);
+                    NSString *s = [[NSString alloc] initWithBytes:&c1 length:4 encoding:NSUTF32LittleEndianStringEncoding];
+                    [strSet appendString:s];
+                }
+            }
+        }
+    }
+    
+    //Test full set of possible URLQueryAllowedCharacterSet characters
+    NSString* encodedSet = [[IterableAPI sharedInstance] encodeURLParam:strSet];
+    XCTAssertNotEqual(encodedSet, strSet);
+    XCTAssert([encodedSet isEqualToString:@"!$&'()*%2B,-./0123456789:;=?@ABCDEFGHIJKLMNOPQRSTUVWXYZ_abcdefghijklmnopqrstuvwxyz~"]);
+    
+    NSString* encoded = [[IterableAPI sharedInstance] encodeURLParam:@"[email protected]"];
+    XCTAssertNotEqual(encoded, @"[email protected]");
+    XCTAssert([encoded isEqualToString:@"you%[email protected]"]);
+    
+    NSString* emptySet = [[IterableAPI sharedInstance] encodeURLParam:@""];
+    XCTAssertEqual(emptySet, @"");
+    XCTAssert([emptySet isEqualToString:@""]);
+    
+    NSString* nilSet = [[IterableAPI sharedInstance] encodeURLParam:nil];
+    XCTAssertEqual(nilSet, nil);
+}
+
 @end