AWSS3GetObjectRequest ifModifiedSince不起作用 [英] AWSS3GetObjectRequest ifModifiedSince not working
问题描述
针对 iOS 7+构建的版本， 基于 Xcode 6.1构建， 使用Amazon SDK ，AWSiOSSDKv2 2.0.12， 在iPhone 5s和iPad 2上进行测试
我正在使用适用于iOS的Amazon SDK从Amazon S3存储桶下载图像. 下载工作正常，但我想使用ifModifiedSince属性仅检索自特定日期以来已被修改的图像 (请参见 http://docs.aws .amazon.com/AWSiOSSDK/latest/Classes/AWSS3GetObjectRequest.html#//api/name/ifModifiedSince )
但是，这不起作用.即使我指定的ifModifiedSince日期晚于S3上文件的修改日期，也会返回文件.
根据Amazon文档: ifModifiedSince -
仅当对象自指定以来已被修改时，才返回该对象 时间，否则返回304(未修改).
因此，我不确定我做错了什么还是Amazon SDK中存在错误.
这是我的代码:
-(void)downloadPhotoWithName:(NSString*)name completed:(retrievedImage)completed {
NSFileManager *manager = [NSFileManager defaultManager];
NSArray *cachePaths = NSSearchPathForDirectoriesInDomains(NSCachesDirectory, NSUserDomainMask, YES);
NSString *cacheDirectory = [cachePaths firstObject];
NSString *filename = [NSString stringWithFormat:@"%@.jpg", name];
NSString *filePath = [cacheDirectory stringByAppendingPathComponent:filename];
AWSS3 *transferManager = [AWSS3 defaultS3];
AWSS3GetObjectRequest *profilePhoto = [[AWSS3GetObjectRequest alloc] init];
profilePhoto.bucket = S3BUCKETNAMEIMAGE;
profilePhoto.key = filename;
if ([manager fileExistsAtPath:filePath isDirectory:NULL]) {
NSDictionary *att = [manager attributesOfItemAtPath:filePath error:nil];
if (att) {
//Get the date of when the file was modified so we can request to retrieve
//the file only if it was modified SINCE that date
NSDate *modifiedDate = [att objectForKey:NSFileModificationDate];
if (modifiedDate) {
profilePhoto.ifModifiedSince = modifiedDate;
}
}
}
[[transferManager getObject:profilePhoto] continueWithBlock:^id(BFTask *task) {
//If it was working we should get a 304 not the image file
if (task.result) {
AWSS3GetObjectOutput *output = (AWSS3GetObjectOutput*)task.result;
NSData *imageData = (NSData*)output.body;
if (imageData) {
NSDictionary* attr = [NSDictionary dictionaryWithObjectsAndKeys:output.lastModified, NSFileModificationDate, NULL];
//The log confirms that the date I am passing for ifModifiedSince is LATER THAN
//the last modified date of the file on S3
//but the the image file is returned anyway.. is it a problem with Amazon ?
NSLog(@"output.lastModified: %@\nmodifiedDate: %@", output.lastModified, profilePhoto.ifModifiedSince);
if ([manager createFileAtPath:filePath contents:imageData attributes:attr]) {
completed(imageData);
}
else {
NSLog(@"Could not save image to disk for some reason");
completed(nil);
}
}
else {
completed(nil);
}
}
else if (task.error) {
NSLog(@"DownloadPhotoError: %@", task.error);
completed(nil);
}
return nil;
}];
}
我们已经发布了适用于iOS 2.0.14的AWS Mobile SDK.它应该解决时间格式问题.
Building for iOS 7+ , Building on Xcode 6.1 , Using Amazon SDK AWSiOSSDKv2 2.0.12 , Testing on iPhone 5s and iPad 2
I am downloading images from my Amazon S3 bucket with the Amazon SDK for iOS. The downloading is working fine but I want to use the ifModifiedSince property to retrieve only images that have been modified since a certain date (see http://docs.aws.amazon.com/AWSiOSSDK/latest/Classes/AWSS3GetObjectRequest.html#//api/name/ifModifiedSince )
However, this is not working. Even when I specify a ifModifiedSince date that is LATER THAN the modified date of the file on S3, the file is returned.
According to the Amazon documentation: ifModifiedSince -
Return the object only if it has been modified since the specified time, otherwise return a 304 (not modified).
So I am not sure if I am doing something wrong or Amazon has a bug in the SDK.
Here is my code:
-(void)downloadPhotoWithName:(NSString*)name completed:(retrievedImage)completed {
NSFileManager *manager = [NSFileManager defaultManager];
NSArray *cachePaths = NSSearchPathForDirectoriesInDomains(NSCachesDirectory, NSUserDomainMask, YES);
NSString *cacheDirectory = [cachePaths firstObject];
NSString *filename = [NSString stringWithFormat:@"%@.jpg", name];
NSString *filePath = [cacheDirectory stringByAppendingPathComponent:filename];
AWSS3 *transferManager = [AWSS3 defaultS3];
AWSS3GetObjectRequest *profilePhoto = [[AWSS3GetObjectRequest alloc] init];
profilePhoto.bucket = S3BUCKETNAMEIMAGE;
profilePhoto.key = filename;
if ([manager fileExistsAtPath:filePath isDirectory:NULL]) {
NSDictionary *att = [manager attributesOfItemAtPath:filePath error:nil];
if (att) {
//Get the date of when the file was modified so we can request to retrieve
//the file only if it was modified SINCE that date
NSDate *modifiedDate = [att objectForKey:NSFileModificationDate];
if (modifiedDate) {
profilePhoto.ifModifiedSince = modifiedDate;
}
}
}
[[transferManager getObject:profilePhoto] continueWithBlock:^id(BFTask *task) {
//If it was working we should get a 304 not the image file
if (task.result) {
AWSS3GetObjectOutput *output = (AWSS3GetObjectOutput*)task.result;
NSData *imageData = (NSData*)output.body;
if (imageData) {
NSDictionary* attr = [NSDictionary dictionaryWithObjectsAndKeys:output.lastModified, NSFileModificationDate, NULL];
//The log confirms that the date I am passing for ifModifiedSince is LATER THAN
//the last modified date of the file on S3
//but the the image file is returned anyway.. is it a problem with Amazon ?
NSLog(@"output.lastModified: %@\nmodifiedDate: %@", output.lastModified, profilePhoto.ifModifiedSince);
if ([manager createFileAtPath:filePath contents:imageData attributes:attr]) {
completed(imageData);
}
else {
NSLog(@"Could not save image to disk for some reason");
completed(nil);
}
}
else {
completed(nil);
}
}
else if (task.error) {
NSLog(@"DownloadPhotoError: %@", task.error);
completed(nil);
}
return nil;
}];
}
We've released the AWS Mobile SDK for iOS 2.0.14. It should address the time formatting issue.
这篇关于AWSS3GetObjectRequest ifModifiedSince不起作用的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！
