Add support for claims like auth_time (#569)

Author: AkshatG6

GoogleSignIn/Sources/GIDClaim.m

@@ -0,0 +1,75 @@
+/*
+ * Copyright 2025 Google LLC
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#import "GoogleSignIn/Sources/Public/GoogleSignIn/GIDClaim.h"
+
+NSString * const kAuthTimeClaimName = @"auth_time";
+
+// Private interface to declare the internal initializer
+@interface GIDClaim ()
+
+- (instancetype)initWithName:(NSString *)name
+                   essential:(BOOL)essential NS_DESIGNATED_INITIALIZER;
+
+@end
+
+@implementation GIDClaim
+
+// Private designated initializer
+- (instancetype)initWithName:(NSString *)name essential:(BOOL)essential {
+  self = [super init];
+  if (self) {
+    _name = [name copy];
+    _essential = essential;
+  }
+  return self;
+}
+
+#pragma mark - Factory Methods
+
++ (instancetype)authTimeClaim {
+  return [[self alloc] initWithName:kAuthTimeClaimName essential:NO];
+}
+
++ (instancetype)essentialAuthTimeClaim {
+  return [[self alloc] initWithName:kAuthTimeClaimName essential:YES];
+}
+
+#pragma mark - NSObject
+
+- (BOOL)isEqual:(id)object {
+  // 1. Check if the other object is the same instance in memory.
+  if (self == object) {
+    return YES;
+  }
+
+  // 2. Check if the other object is not a GIDTokenClaim instance.
+  if (![object isKindOfClass:[GIDClaim class]]) {
+    return NO;
+  }
+
+  // 3. Compare the properties that define equality.
+  GIDClaim *other = (GIDClaim *)object;
+  return [self.name isEqualToString:other.name] &&
+         self.isEssential == other.isEssential;
+}
+
+- (NSUInteger)hash {
+  // The hash value should be based on the same properties used in isEqual:
+  return self.name.hash ^ @(self.isEssential).hash;
+}
+
+@end

GoogleSignIn/Sources/GIDClaimsInternalOptions.h

@@ -0,0 +1,55 @@
+/*
+ * Copyright 2025 Google LLC
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#import <Foundation/Foundation.h>
+
+@class GIDClaim;
+
+NS_ASSUME_NONNULL_BEGIN
+
+extern NSString *const kGIDClaimErrorDescription;
+extern NSString *const kGIDClaimEssentialPropertyKeyName;
+extern NSString *const kGIDClaimKeyName;
+
+@protocol GIDJSONSerializer;
+
+/**
+ * An internal utility class for processing and serializing the `NSSet` of `GIDClaim` objects
+ * into the `JSON` format required for an `OIDAuthorizationRequest`.
+ */
+@interface GIDClaimsInternalOptions : NSObject
+
+- (instancetype)init;
+
+- (instancetype)initWithJSONSerializer:
+    (id<GIDJSONSerializer>)jsonSerializer NS_DESIGNATED_INITIALIZER;
+
+/**
+ * Processes the `NSSet` of `GIDClaim` objects, handling ambiguous claims,
+ * and returns a `JSON` string.
+ *
+ * @param claims The `NSSet` of `GIDClaim` objects provided by the developer.
+ * @param error A pointer to an `NSError` object to be populated if an error occurs (e.g., if a
+ * claim is requested as both essential and non-essential).
+ * @return A `JSON` string representing the claims request, or `nil` if the input is empty or an
+ * error occurs.
+ */
+- (nullable NSString *)validatedJSONStringForClaims:(nullable NSSet<GIDClaim *> *)claims
+                                              error:(NSError *_Nullable *_Nullable)error;
+
+@end
+
+NS_ASSUME_NONNULL_END

GoogleSignIn/Sources/GIDClaimsInternalOptions.m

@@ -0,0 +1,91 @@
+/*
+ * Copyright 2025 Google LLC
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#import "GoogleSignIn/Sources/GIDClaimsInternalOptions.h"
+
+#import "GoogleSignIn/Sources/GIDJSONSerializer/API/GIDJSONSerializer.h"
+#import "GoogleSignIn/Sources/GIDJSONSerializer/Implementation/GIDJSONSerializerImpl.h"
+#import "GoogleSignIn/Sources/Public/GoogleSignIn/GIDSignIn.h"
+#import "GoogleSignIn/Sources/Public/GoogleSignIn/GIDClaim.h"
+
+NSString * const kGIDClaimErrorDescription =
+    @"The claim was requested as both essential and non-essential. "
+    @"Please provide only one version.";
+NSString * const kGIDClaimEssentialPropertyKey = @"essential";
+NSString * const kGIDClaimKeyName = @"id_token";
+
+@interface GIDClaimsInternalOptions ()
+@property(nonatomic, readonly) id<GIDJSONSerializer> jsonSerializer;
+@end
+
+@implementation GIDClaimsInternalOptions
+
+- (instancetype)init {
+  return [self initWithJSONSerializer:[[GIDJSONSerializerImpl alloc] init]];
+}
+
+- (instancetype)initWithJSONSerializer:(id<GIDJSONSerializer>)jsonSerializer {
+  if (self = [super init]) {
+    _jsonSerializer = jsonSerializer;
+  }
+  return self;
+}
+
+- (nullable NSString *)validatedJSONStringForClaims:(nullable NSSet<GIDClaim *> *)claims
+                                              error:(NSError *_Nullable *_Nullable)error {
+  if (!claims || claims.count == 0) {
+    return nil;
+  }
+
+  // === Step 1: Check for claims with ambiguous essential property. ===
+  NSMutableDictionary<NSString *, GIDClaim *> *validClaims =
+    [[NSMutableDictionary alloc] init];
+
+  for (GIDClaim *currentClaim in claims) {
+    GIDClaim *existingClaim = validClaims[currentClaim.name];
+
+    // Check for a conflict: a claim with the same name but different essentiality.
+    if (existingClaim && existingClaim.isEssential != currentClaim.isEssential) {
+      if (error) {
+        *error = [NSError errorWithDomain:kGIDSignInErrorDomain
+                                     code:kGIDSignInErrorCodeAmbiguousClaims
+                                 userInfo:@{
+                                   NSLocalizedDescriptionKey:kGIDClaimErrorDescription
+                                 }];
+      }
+      return nil;
+    }
+    validClaims[currentClaim.name] = currentClaim;
+  }
+
+  // === Step 2: Build the dictionary structure required for OIDC JSON ===
+  NSMutableDictionary<NSString *, NSDictionary *> *claimsDictionary =
+    [[NSMutableDictionary alloc] init];
+  for (GIDClaim *claim in validClaims.allValues) {
+    if (claim.isEssential) {
+      claimsDictionary[claim.name] = @{ kGIDClaimEssentialPropertyKey: @YES };
+    } else {
+      claimsDictionary[claim.name] = @{ kGIDClaimEssentialPropertyKey: @NO };
+    }
+  }
+  NSDictionary<NSString *, id> *finalRequestDictionary =
+    @{ kGIDClaimKeyName: claimsDictionary };
+
+  // === Step 3: Serialize the final dictionary into a JSON string ===
+  return [_jsonSerializer stringWithJSONObject:finalRequestDictionary error:error];
+}
+
+@end

GoogleSignIn/Sources/GIDJSONSerializer/API/GIDJSONSerializer.h

@@ -0,0 +1,38 @@
+/*
+ * Copyright 2025 Google LLC
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#import <Foundation/Foundation.h>
+
+NS_ASSUME_NONNULL_BEGIN
+
+/**
+ * A protocol for serializing an `NSDictionary` into a JSON string.
+ */
+@protocol GIDJSONSerializer <NSObject>
+
+/**
+ * Serializes the given dictionary into a `JSON` string.
+ *
+ * @param jsonObject The dictionary to be serialized.
+ * @param error A pointer to an `NSError` object to be populated upon failure.
+ * @return A `JSON` string representation of the dictionary, or `nil` if an error occurs.
+ */
+- (nullable NSString *)stringWithJSONObject:(NSDictionary<NSString *, id> *)jsonObject
+                                      error:(NSError *_Nullable *_Nullable)error;
+
+@end
+
+NS_ASSUME_NONNULL_END

GoogleSignIn/Sources/GIDJSONSerializer/Fake/GIDFakeJSONSerializerImpl.h

@@ -0,0 +1,37 @@
+/*
+ * Copyright 2025 Google LLC
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#import "GoogleSignIn/Sources/GIDJSONSerializer/API/GIDJSONSerializer.h"
+
+NS_ASSUME_NONNULL_BEGIN
+
+/** A fake implementation of `GIDJSONSerializer` for testing purposes. */
+@interface GIDFakeJSONSerializerImpl : NSObject <GIDJSONSerializer>
+
+/**
+ * An error to be returned by `stringWithJSONObject:error:`.
+ *
+ * If this property is set, `stringWithJSONObject:error:` will return `nil` and
+ * populate the error parameter with this error.
+ */
+@property(nonatomic, nullable) NSError *serializationError;
+
+/** The dictionary passed to the serialization method. */
+@property(nonatomic, readonly, nullable) NSDictionary<NSString *, id> *capturedJSONObject;
+
+@end
+
+NS_ASSUME_NONNULL_END

GoogleSignIn/Sources/GIDJSONSerializer/Fake/GIDFakeJSONSerializerImpl.m

@@ -0,0 +1,46 @@
+/*
+ * Copyright 2025 Google LLC
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#import "GoogleSignIn/Sources/GIDJSONSerializer/Fake/GIDFakeJSONSerializerImpl.h"
+
+#import "GoogleSignIn/Sources/GIDJSONSerializer/Implementation/GIDJSONSerializerImpl.h"
+#import "GoogleSignIn/Sources/Public/GoogleSignIn/GIDSignIn.h"
+
+@implementation GIDFakeJSONSerializerImpl
+
+- (nullable NSString *)stringWithJSONObject:(NSDictionary<NSString *, id> *)jsonObject
+                                      error:(NSError *_Nullable *_Nullable)error {
+  _capturedJSONObject = [jsonObject copy];
+
+  // Check if a serialization error should be simulated.
+  if (self.serializationError) {
+    if (error) {
+      *error = self.serializationError;
+    }
+    return nil;
+  }
+
+  // If not failing, fall back to the real serialization path.
+  NSData *jsonData = [NSJSONSerialization dataWithJSONObject:jsonObject
+                                                 options:0
+                                                   error:error];
+  if (!jsonData) {
+      return nil;
+  }
+  return [[NSString alloc] initWithData:jsonData encoding:NSUTF8StringEncoding];
+}
+
+@end

GoogleSignIn/Sources/GIDJSONSerializer/Implementation/GIDJSONSerializerImpl.h

@@ -0,0 +1,26 @@
+/*
+ * Copyright 2025 Google LLC
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#import "GoogleSignIn/Sources/GIDJSONSerializer/API/GIDJSONSerializer.h"
+
+NS_ASSUME_NONNULL_BEGIN
+
+extern NSString *const kGIDJSONSerializationErrorDescription;
+
+@interface GIDJSONSerializerImpl : NSObject <GIDJSONSerializer>
+@end
+
+NS_ASSUME_NONNULL_END