First pass at datafile download by checking the 'If-Modified-Since' in the HTTP header.

alda-optimizely · alda-optimizely · commit 4336f635e3f2 · 2016-11-28T07:15:13.000+02:00
diff --git a/OptimizelySDKCore/OptimizelySDKCore/OptimizelySDKCore.h b/OptimizelySDKCore/OptimizelySDKCore/OptimizelySDKCore.h
@@ -23,15 +23,15 @@
 #import "OPTLYEventBuilder.h"
 #import "OPTLYEventDispatcher.h"
 #import "OPTLYExperiment.h"
+#import "OPTLYLog.h"
 #import "OPTLYLogger.h"
 #import "OPTLYLoggerMessages.h"
 #import "OPTLYProjectConfig.h"
 #import "OPTLYProjectConfigBuilder.h"
-#import "OPTLYVariable.h"
-#import "OPTLYVariation.h"
-#import "OPTLYLog.h"
 #import "OPTLYQueue.h"
 #import "OPTLYUserProfile.h"
+#import "OPTLYVariable.h"
+#import "OPTLYVariation.h"
 
 FOUNDATION_EXPORT double OptimizelySDKCoreVersionNumber;
 FOUNDATION_EXPORT const unsigned char OptimizelySDKCoreVersionString[];
diff --git a/OptimizelySDKDatafileManager/OptimizelySDKDatafileManager/OPTLYDatafileManager.m b/OptimizelySDKDatafileManager/OptimizelySDKDatafileManager/OPTLYDatafileManager.m
@@ -17,6 +17,7 @@
 #import <UIKit/UIKit.h>
 #import <OptimizelySDKCore/OPTLYErrorHandler.h>
 #import <OptimizelySDKCore/OPTLYLog.h>
+#import <OptimizelySDKCore/OPTLYLogger.h>
 #import <OptimizelySDKShared/OPTLYDataStore.h>
 #import <OptimizelySDKShared/OPTLYNetworkService.h>
 #import "OPTLYDatafileManager.h"
@@ -62,14 +63,23 @@ - (instancetype)initWithBuilder:(OPTLYDatafileManagerBuilder *)builder {
 
 - (void)downloadDatafile:(NSString *)projectId completionHandler:(OPTLYHTTPRequestManagerResponse)completion {
     OPTLYLogInfo(@"Downloading datafile: %@", projectId);
+    
+    NSString *lastSavedModifiedDate = [self getLastModifiedDate:projectId];
     [self.networkService downloadProjectConfig:self.projectId
+                                  lastModified:lastSavedModifiedDate
                              completionHandler:^(NSData * _Nullable data, NSURLResponse * _Nullable response, NSError * _Nullable error) {
          if (error != nil) {
              [self.errorHandler handleError:error];
          }
          else if ([(NSHTTPURLResponse *)response statusCode] == 200) { // got datafile OK
              [self saveDatafile:data];
-             OPTLYLogInfo(@"Datafile for project ID %@ downloaded. Saving datafile.");
+             
+             // save the last modified date
+             NSHTTPURLResponse *httpResponse = (NSHTTPURLResponse *)response;
+             NSDictionary *dictionary = [httpResponse allHeaderFields];
+             NSString *lastModifiedDate = [dictionary valueForKey:@"Last-Modified"];
+             [self saveLastModifiedDate:lastModifiedDate project:projectId];
+             OPTLYLogInfo(@"Datafile for project ID %@ downloaded. Saving datafile and last modified date: %@", lastModifiedDate);
          }
          else {
              // TODO: Josh W. handle bad response
@@ -99,6 +109,33 @@ - (BOOL)isDatafileCached {
     return isCached;
 }
 
+# pragma mark - Persistence for Last Modified Date
+- (void)saveLastModifiedDate:(nonnull NSString *)lastModifiedDate
+                     project:(nonnull NSString *)projectId {
+    
+    NSDictionary *userProfileData = [self.dataStore getUserDataForType:OPTLYDataStoreDataTypeDatafile];
+    NSMutableDictionary *userProfileDataMutable = userProfileData ? [userProfileData mutableCopy] : [NSMutableDictionary new];
+    userProfileDataMutable[projectId] = lastModifiedDate;
+    [self.dataStore saveUserData:userProfileDataMutable
+                            type:OPTLYDataStoreDataTypeDatafile];
+}
+
+- (nullable NSString *)getLastModifiedDate:(nonnull NSString *)projectId {
+    NSDictionary *userData = [self.dataStore getUserDataForType:OPTLYDataStoreDataTypeDatafile];
+    NSString *lastModifiedDate = [userData objectForKey:projectId];
+
+    NSString *logMessage = @"";
+    if ([lastModifiedDate length]) {
+        logMessage = [NSString stringWithFormat:@"[DATAFILE MANAGER] Last modified date %@ found for project %@.", lastModifiedDate, projectId];
+    } else {
+        logMessage = [NSString stringWithFormat:@"[DATAFILE MANAGER] Last modified date not found for project %@.", projectId];
+    }
+    [self.logger logMessage:logMessage withLevel:OptimizelyLogLevelDebug];
+    
+    return lastModifiedDate;
+}
+
+
 #pragma mark - Application Lifecycle Handlers
 - (void)setupApplicationNotificationHandlers {
     NSNotificationCenter *defaultCenter = [NSNotificationCenter defaultCenter];
diff --git a/OptimizelySDKShared/OptimizelySDKShared/OPTLYHTTPRequestManager.h b/OptimizelySDKShared/OptimizelySDKShared/OPTLYHTTPRequestManager.h
@@ -57,4 +57,16 @@ typedef void (^OPTLYHTTPRequestManagerResponse)(NSData * _Nullable data, NSURLRe
 - (void)POSTWithParameters:(nullable NSDictionary *)parameters
          completionHandler:(nullable OPTLYHTTPRequestManagerResponse)completion;
 
+/**
+ * A GET response with the following condition:
+ * If the requested variant has not been modified since the time specified in the 
+ * "If-Modified-Since" field, an entity will not be returned from the server; instead, 
+ * a 304 (not modified) response will be returned without any message-body.
+ *
+ * @param lastModifiedDate - The date since the URL request was last modified
+ * @param completion - The completion block of type OPTLYHTTPRequestManagerResponse
+ */
+- (void)GETIfModifiedSince:(nonnull NSString *)lastModifiedDate
+         completionHandler:(nullable OPTLYHTTPRequestManagerResponse)completion;
+
 @end
diff --git a/OptimizelySDKShared/OptimizelySDKShared/OPTLYHTTPRequestManager.m b/OptimizelySDKShared/OptimizelySDKShared/OPTLYHTTPRequestManager.m
@@ -14,6 +14,7 @@
  * limitations under the License.                                           *
  ***************************************************************************/
 
+#import <OptimizelySDKCore/OPTLYLog.h>
 #import "OPTLYHTTPRequestManager.h"
 
 static NSString * const kHTTPRequestMethodGet = @"GET";
@@ -91,8 +92,28 @@ - (void)POSTWithParameters:(NSDictionary *)parameters
         
         [uploadTask resume];
     }
+}
+
+- (void)GETIfModifiedSince:(nonnull NSString *)lastModifiedDate
+         completionHandler:(nullable OPTLYHTTPRequestManagerResponse)completion
+{
+    NSMutableURLRequest *request = [NSMutableURLRequest requestWithURL:[self url]];
+    [request setValue:lastModifiedDate forHTTPHeaderField:@"If-Modified-Since"];
+    
+    NSURLSession *ephemeralSession = [NSURLSession sessionWithConfiguration:[NSURLSessionConfiguration ephemeralSessionConfiguration]];
+    NSURLSessionDataTask *dataTask = [ephemeralSession dataTaskWithRequest:request completionHandler:^(NSData * _Nullable data, NSURLResponse * _Nullable response, NSError * _Nullable error) {
+        NSHTTPURLResponse *httpResponse = (NSHTTPURLResponse *)response;
+    
+        int responseCode = (int)[httpResponse statusCode];
+        OPTLYLogInfo(@"All headers: %@", [httpResponse allHeaderFields]);
+        OPTLYLogInfo(@"Status code:: %d", responseCode);
+        
+        if (completion) {
+            completion(data, response, error);
+        }
+    }];
     
-    // TODO (Alda) - Log NSJSONSerializationnerror when the logger class is implemented
+    [dataTask resume];
 }
 
 # pragma mark - Helper Methods
diff --git a/OptimizelySDKShared/OptimizelySDKShared/OPTLYManager.h b/OptimizelySDKShared/OptimizelySDKShared/OPTLYManager.h
@@ -59,6 +59,9 @@
  */
 - (void)initializeClientWithCallback:(void(^ _Nullable)(NSError * _Nullable error, OPTLYClient * _Nullable client))callback;
 
+/*
+ * Gets the cached Optimizely client. 
+ */
 - (nullable OPTLYClient *)getOptimizely;
 
 @end
diff --git a/OptimizelySDKShared/OptimizelySDKShared/OPTLYManager.m b/OptimizelySDKShared/OptimizelySDKShared/OPTLYManager.m
@@ -14,18 +14,19 @@
  * limitations under the License.                                           *
  ***************************************************************************/
 
-#import "OPTLYManager.h"
-#import "OPTLYClient.h"
-#import "OPTLYNetworkService.h"
+#import <OptimizelySDKCore/OPTLYDatafileManager.h>
 #import <OptimizelySDKCore/OPTLYErrorHandler.h>
 #import <OptimizelySDKCore/OPTLYErrorHandlerMessages.h>
 #import <OptimizelySDKCore/OPTLYLogger.h>
 #import <OptimizelySDKCore/OPTLYLoggerMessages.h>
+#import <OptimizelySDKShared/OPTLYManagerBuilder.h>
+#import "OPTLYClient.h"
+#import "OPTLYManager.h"
+#import "OPTLYManagerBuilder.h"
+#import "OPTLYNetworkService.h"
 
-@interface OPTLYManager ()
-
+@interface OPTLYManager()
 @property (strong, readwrite, nonatomic, nullable) OPTLYClient *optimizelyClient;
-
 @end
 
 @implementation OPTLYManager
@@ -103,22 +104,23 @@ - (OPTLYClient *)initializeClientWithDatafile:(NSData *)datafile {
 }
 
 - (void)initializeClientWithCallback:(void (^)(NSError * _Nullable, OPTLYClient * _Nullable))callback {
-    OPTLYNetworkService *networkService = [[OPTLYNetworkService alloc] init];
-    [networkService downloadProjectConfig:self.projectId
-                        completionHandler:^(NSData * _Nullable data, NSURLResponse * _Nullable response, NSError * _Nullable error) {
-                            if (error != nil) {
-                                callback(error, nil);
-                            }
-                            else {
-                                OPTLYClient *client = [OPTLYClient initWithBuilderBlock:^(OPTLYClientBuilder * _Nonnull builder) {
-                                    builder.datafile = data;
-                                }];
-                                if (client.optimizely != nil) {
-                                    self.optimizelyClient = client;
-                                }
-                                callback(nil, client);
-                            }
-                        }];
+    [self.datafileManager downloadDatafile:self.projectId completionHandler:^(NSData * _Nullable data, NSURLResponse * _Nullable response, NSError * _Nullable error) {
+        OPTLYClient *client = nil;
+        if (!error) {
+            client = [OPTLYClient initWithBuilderBlock:^(OPTLYClientBuilder * _Nonnull builder) {
+                builder.datafile = data;
+            }];
+            if (client.optimizely) {
+                self.optimizelyClient = client;
+            }
+        } else {
+            // TODO - log error
+        }
+        
+        if (callback) {
+            callback(error, client);
+        }
+    }];
 }
 
 - (OPTLYClient *)getOptimizely {
diff --git a/OptimizelySDKShared/OptimizelySDKShared/OPTLYManagerBuilder.h b/OptimizelySDKShared/OptimizelySDKShared/OPTLYManagerBuilder.h
@@ -17,7 +17,6 @@
 #import <Foundation/Foundation.h>
 
 @protocol OPTLYDatafileManager, OPTLYErrorHandler, OPTLYEventDispatcher, OPTLYLogger;
-
 @class OPTLYManagerBuilder;
 
 typedef void (^OPTLYManagerBuilderBlock)(OPTLYManagerBuilder * _Nullable builder);
diff --git a/OptimizelySDKShared/OptimizelySDKShared/OPTLYNetworkService.h b/OptimizelySDKShared/OptimizelySDKShared/OPTLYNetworkService.h
@@ -26,10 +26,22 @@ NS_ASSUME_NONNULL_END
 /**
  * Download the project config file from remote server
  *
- * @param projectId - projectId of the project config to download
- * @param completion - The completion block of type OPTLYHTTPRequestManagerResponse
+ * @param projectId The project ID of the datafile to download.
+ * @param completion The completion block of type OPTLYHTTPRequestManagerResponse
  */
 - (void)downloadProjectConfig:(nonnull NSString *)projectId
             completionHandler:(nullable OPTLYHTTPRequestManagerResponse)completion;
 
+/**
+ * Download the project config file from remote server only if it
+ * has been modified.
+ *
+ * @param projectId The project ID of the datafile to download.
+ * @param lastModifiedDate The date the datafile was last modified.
+ * @param completion The completion block of type OPTLYHTTPRequestManagerResponse
+ */
+- (void)downloadProjectConfig:(nonnull NSString *)projectId
+                 lastModified:(nonnull NSString *)lastModifiedDate
+            completionHandler:(nullable OPTLYHTTPRequestManagerResponse)completion;
+
 @end
diff --git a/OptimizelySDKShared/OptimizelySDKShared/OPTLYNetworkService.m b/OptimizelySDKShared/OptimizelySDKShared/OPTLYNetworkService.m
@@ -17,33 +17,42 @@
 #import "OPTLYNetworkService.h"
 
 // ---- Datafile Download URLs ----
-NSString * const OPTLYNetworkServiceCDNServerURL = @"https://cdn.optimizely.com/";
-NSString * const OPTLYNetworkServiceS3ServerURL = @"https://optimizely.s3.amazonaws.com/";
+NSString * const OPTLYNetworkServiceCDNServerURL    = @"https://cdn.optimizely.com/";
+NSString * const OPTLYNetworkServiceS3ServerURL     = @"https://optimizely.s3.amazonaws.com/";
 
 @implementation OPTLYNetworkService
 
-- (void)downloadProjectConfig:(NSString *)projectId completionHandler:(OPTLYHTTPRequestManagerResponse)completion
+- (void)downloadProjectConfig:(nonnull NSString *)projectId
+                 lastModified:(nonnull NSString *)lastModifiedDate
+            completionHandler:(nullable OPTLYHTTPRequestManagerResponse)completion
 {
     NSURL *cdnURL = [NSURL URLWithString:OPTLYNetworkServiceCDNServerURL];
     NSURL *cdnConfigFilePathURL = [self projectConfigURLPath:cdnURL withProjectId:projectId];
     
     OPTLYHTTPRequestManager *requestManager = [[OPTLYHTTPRequestManager alloc] initWithURL:cdnConfigFilePathURL];
-    [requestManager GET:^(NSData *data, NSURLResponse *response, NSError *error) {
-        if (error)
-        {
-            // TODO (Alda) - Handle error. Possible ways of handling error:
-            //     1. Log GET error when the logger class is implemented
-            //     2. Retry download with backoff
-            //     3. Return error to users
-            //     4. Telemetry error log?
-        }
+    
+     [requestManager GETIfModifiedSince:lastModifiedDate
+                      completionHandler:^(NSData *data, NSURLResponse *response, NSError *error) {
             
         if (completion) {
             completion(data, response, error);
         }
     }];
 }
 
+- (void)downloadProjectConfig:(NSString *)projectId completionHandler:(OPTLYHTTPRequestManagerResponse)completion
+{
+    NSURL *cdnURL = [NSURL URLWithString:OPTLYNetworkServiceCDNServerURL];
+    NSURL *cdnConfigFilePathURL = [self projectConfigURLPath:cdnURL withProjectId:projectId];
+    
+    OPTLYHTTPRequestManager *requestManager = [[OPTLYHTTPRequestManager alloc] initWithURL:cdnConfigFilePathURL];
+   [requestManager GET:^(NSData *data, NSURLResponse *response, NSError *error) {
+       if (completion) {
+           completion(data, response, error);
+       }
+   }];
+}
+
 # pragma mark - Helper Methods
 
 - (NSURL *)projectConfigURLPath:(NSURL *)url
diff --git a/OptimizelySDKShared/OptimizelySDKShared/OptimizelySDKShared.h b/OptimizelySDKShared/OptimizelySDKShared/OptimizelySDKShared.h
@@ -15,16 +15,21 @@
  ***************************************************************************/
 
 #import <OptimizelySDKCore/OptimizelySDKCore.h>
-#import "OPTLYManager.h"
-#import "OPTLYHTTPRequestManager.h"
-#import "OPTLYNetworkService.h"
-#import "OPTLYDataStore.h"
 #import "OPTLYClient.h"
-#import "OPTLYFileManager.h"
+#import "OPTLYClientBuilder.h"
+#import "OPTLYDataStore.h"
 #if TARGET_OS_IOS
 #import "OPTLYDatabase.h"
 #import "OPTLYDatabaseEntity.h"
 #endif
+#import "OPTLYFileManager.h"
+#import "OPTLYHTTPRequestManager.h"
+#import "OPTLYManager.h"
+#import "OPTLYManagerBuilder.h"
+#import "OPTLYNetworkService.h"
+
+
+
 
 //! Project version number for OptimizelySDKShared.
 FOUNDATION_EXPORT double OptimizelySDKSharedVersionNumber;
