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NSFileManager よく使うファイル操作メソッド(保存、削除、取得、列挙)

Last updated at Posted at 2013-02-21

NSUserDefaultsでなく/tmpや/Docmentsに保存したりファイル操作をしたい場合に役立ちそうなメソッドです。
これを元にいろいろなカスタマイズも出来るかと思います。

FileHelper.h
/* tmp */
- (NSString*)temporaryDirectory;
/* /tmp/fileName */
- (NSString*)temporaryDirectoryWithFileName:(NSString*)fileName;

/* /Documents */
- (NSString*)documentDirectory;
/* /Documents/fileName */
- (NSString*)documentDirectoryWithFileName:(NSString*)fileName;

/* pathのファイルが存在しているか */
- (BOOL)fileExistsAtPath:(NSString*)path;

/* pathのファイルがelapsedTimeを超えているか */
- (BOOL)isElapsedFileModificationDateWithPath:(NSString*)path elapsedTimeInterval:(NSTimeInterval)elapsedTime;

/* directoryPath内のextension(拡張子)と一致する全てのファイル名 */
- (NSArray*)fileNamesAtDirectoryPath:(NSString*)directoryPath extension:(NSString*)extension;

/* pathのファイルを削除 */
- (BOOL)removeFilePath:(NSString*)path;
FileHelper.m
- (NSString*)temporaryDirectory
{
    return NSTemporaryDirectory();
}

- (NSString*)temporaryDirectoryWithFileName:(NSString*)fileName
{
    return [[self temporaryDirectory] stringByAppendingPathComponent:fileName];
}

- (NSString*)documentDirectory
{
    NSArray *paths = NSSearchPathForDirectoriesInDomains(
                                                         NSDocumentDirectory,
                                                         NSUserDomainMask,
                                                         YES);
    return [paths objectAtIndex:0];
}

- (NSString*)documentDirectoryWithFileName:(NSString*)fileName
{
    return [[self documentDirectory] stringByAppendingPathComponent:fileName];
}

- (BOOL)fileExistsAtPath:(NSString*)path
{
    NSFileManager* fileManager = [[NSFileManager alloc] init];
	/* ファイルが存在するか */
    if ([fileManager fileExistsAtPath:path]) {
        return YES;
    } else {
        return NO;
    }
}

- (BOOL)isElapsedFileModificationDateWithPath:(NSString*)path elapsedTimeInterval:(NSTimeInterval)elapsedTime
{
    if ([self fileExistsAtPath:path]) {
        NSError *error = nil;
        NSDictionary* dicFileAttributes = [[NSFileManager defaultManager] attributesOfItemAtPath:path error:&error];
        if (error) {
            return NO;
        }
        /* 現在時間とファイルの最終更新日時との差を取得 */
        NSTimeInterval diff  = [[NSDate dateWithTimeIntervalSinceNow:0.0] timeIntervalSinceDate:dicFileAttributes.fileModificationDate];
        if(elapsedTime < diff){
            /* ファイルの最終更新日時からelapseTime以上経っている */
            return YES;
        } else {
            return NO;
        }
    }
    return NO;
}

- (NSArray*)fileNamesAtDirectoryPath:(NSString*)directoryPath extension:(NSString*)extension
{
    NSFileManager *fileManager=[[NSFileManager alloc] init];
    NSError *error = nil;
	/* 全てのファイル名 */
    NSArray *allFileName = [fileManager contentsOfDirectoryAtPath:directoryPath error:&error];
    if (error) return nil;
    NSMutableArray *hitFileNames = [[NSMutableArray alloc] init];
    for (NSString *fileName in allFileName) {
        /* 拡張子が一致するか */
        if ([[fileName pathExtension] isEqualToString:extension]) {
            [hitFileNames addObject:fileName];
        }
    }
    return hitFileNames;
}

- (BOOL)removeFilePath:(NSString*)path
{
    NSFileManager *fileManager = [[NSFileManager alloc] init];
    return [fileManager removeItemAtPath:path error:NULL];
}
使用例
/* /tmp内のpngファイルで、最終更新日から1時間以上経過したファイルを全て削除する */
    
/* /tmp内の全てのpngファイル名を取得 */
NSArray *imgFileNames = [self fileNamesAtDirectoryPath:[self temporaryDirectory] extension:@"png"];
for (NSString *fileName in imgFileNames) {
    NSString *filePath = [self temporaryDirectoryWithFileName:fileName];
    /* 最終更新日から1時間経過しているか */
    if ([self isElapsedFileModificationDateWithPath:filePath elapsedTimeInterval:60.0 * 60.0]) {
        /* 削除 */
        [self removeFilePath:filePath];
    }
}
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