GoFrame gfile-内容管理

内容管理

GetContents

• 说明：读取指定路径文件内容，以字符串形式返回。
• 格式: 

func GetContents(path string) string

• 示例：

func ExampleGetContents() {
	// init
	var (
		fileName = "gflie_example.txt"
		tempDir  = gfile.TempDir("gfile_example_content")
		tempFile = gfile.Join(tempDir, fileName)
	)

	// write contents
	gfile.PutContents(tempFile, "goframe example content")

	// It reads and returns the file content as string.
	// It returns empty string if it fails reading, for example, with permission or IO error.
	fmt.Println(gfile.GetContents(tempFile))

	// Output:
	// goframe example content
}

GetContentsWithCache

• 说明：带缓存获取文件内容，可设置缓存超时，文件发生变化自动清除缓存。
• 格式: 

func GetContentsWithCache(path string, duration ...time.Duration) string

• 示例：

func ExampleGetContentsWithCache() {
	// init
	var (
		fileName = "gflie_example.txt"
		tempDir  = gfile.TempDir("gfile_example_cache")
		tempFile = gfile.Join(tempDir, fileName)
	)

	// write contents
	gfile.PutContents(tempFile, "goframe example content")

	// It reads the file content with cache duration of one minute,
	// which means it reads from cache after then without any IO operations within on minute.
	fmt.Println(gfile.GetContentsWithCache(tempFile, time.Minute))

	// write new contents will clear its cache
	gfile.PutContents(tempFile, "new goframe example content")

	// Theres some delay for cache clearing after file content change.
	time.Sleep(time.Second * 1)

	// read contents
	fmt.Println(gfile.GetContentsWithCache(tempFile))

	// May Output:
	// goframe example content
	// new goframe example content
}

GetBytesWithCache

• 说明：带缓存获取文件内容，可设置缓存超时，文件发生变化自动清除缓存，返回​[]byte​。
• 格式: 

func GetBytesWithCache(path string, duration ...time.Duration) []byte

• 示例：

func ExampleGetBytesWithCache() {
	// init
	var (
		fileName = "gflie_example.txt"
		tempDir  = gfile.TempDir("gfile_example_cache")
		tempFile = gfile.Join(tempDir, fileName)
	)

	// write contents
	gfile.PutContents(tempFile, "goframe example content")

	// It reads the file content with cache duration of one minute,
	// which means it reads from cache after then without any IO operations within on minute.
	fmt.Println(gfile.GetBytesWithCache(tempFile, time.Minute))

	// write new contents will clear its cache
	gfile.PutContents(tempFile, "new goframe example content")

	// Theres some delay for cache clearing after file content change.
	time.Sleep(time.Second * 1)

	// read contents
	fmt.Println(gfile.GetBytesWithCache(tempFile))

	// Output:
	// [103 111 102 114 97 109 101 32 101 120 97 109 112 108 101 32 99 111 110 116 101 110 116]
	// [110 101 119 32 103 111 102 114 97 109 101 32 101 120 97 109 112 108 101 32 99 111 110 116 101 110 116]
}

GetBytes

• 说明：读取指定路径文件内容，以字节形式返回。
• 格式: 

func GetBytes(path string) []byte

• 示例：

func ExampleGetBytes() {
	// init
	var (
		fileName = "gflie_example.txt"
		tempDir  = gfile.TempDir("gfile_example_content")
		tempFile = gfile.Join(tempDir, fileName)
	)

	// write contents
	gfile.PutContents(tempFile, "goframe example content")

	// It reads and returns the file content as []byte.
	// It returns nil if it fails reading, for example, with permission or IO error.
	fmt.Println(gfile.GetBytes(tempFile))

	// Output:
	// [103 111 102 114 97 109 101 32 101 120 97 109 112 108 101 32 99 111 110 116 101 110 116]
}

GetBytesTilChar

• 说明：以某个字符定位截取指定长度的文件内容以字节形式返回
• 格式: 

func GetBytesTilChar(reader io.ReaderAt, char byte, start int64) ([]byte, int64)

• 示例：

func ExampleGetBytesTilChar() {
	// init
	var (
		fileName = "gflie_example.txt"
		tempDir  = gfile.TempDir("gfile_example_content")
		tempFile = gfile.Join(tempDir, fileName)
	)

	// write contents
	gfile.PutContents(tempFile, "goframe example content")

	f, _ := gfile.OpenWithFlagPerm(tempFile, os.O_RDONLY, gfile.DefaultPermOpen)

	// GetBytesTilChar returns the contents of the file as []byte
	// until the next specified byte `char` position.
	char, i := gfile.GetBytesTilChar(f, f, 0)
	fmt.Println(char)
	fmt.Println(i)

	// Output:
	// [103 111 102]
	// 2
}

GetBytesByTwoOffsets

• 说明：以指定的区间读取文件内容
• 格式: 

func GetBytesByTwoOffsets(reader io.ReaderAt, start int64, end int64) []byte 

• 示例：

func ExampleGetBytesByTwoOffsets() {
	// init
	var (
		fileName = "gflie_example.txt"
		tempDir  = gfile.TempDir("gfile_example_content")
		tempFile = gfile.Join(tempDir, fileName)
	)

	// write contents
	gfile.PutContents(tempFile, "goframe example content")

	f, _ := gfile.OpenWithFlagPerm(tempFile, os.O_RDONLY, gfile.DefaultPermOpen)

	// GetBytesTilChar returns the contents of the file as []byte
	// until the next specified byte `char` position.
	char := gfile.GetBytesByTwoOffsets(f, 0, 3)
	fmt.Println(char)

	// Output:
	// [103 111 102]
}

PutContents

• 说明：往指定路径文件添加字符串内容。如果文件不存在将会递归的形式自动创建。
• 格式: 

func putContents(path string, data []byte, flag int, perm os.FileMode) error

• 示例：

func ExamplePutContents() {
	// init
	var (
		fileName = "gflie_example.txt"
		tempDir  = gfile.TempDir("gfile_example_content")
		tempFile = gfile.Join(tempDir, fileName)
	)

	// It creates and puts content string into specifies file path.
	// It automatically creates directory recursively if it does not exist.
	gfile.PutContents(tempFile, "goframe example content")

	// read contents
	fmt.Println(gfile.GetContents(tempFile))

	// Output:
	// goframe example content
}

PutBytes

• 说明：以字节形式写入指定文件，如果文件不存在将会递归的形式自动创建
• 格式: 

func PutBytes(path string, content []byte) error

• 示例：

func ExamplePutBytes() {
	// init
	var (
		fileName = "gflie_example.txt"
		tempDir  = gfile.TempDir("gfile_example_content")
		tempFile = gfile.Join(tempDir, fileName)
	)

	// write contents
	gfile.PutBytes(tempFile, []byte("goframe example content"))

	// read contents
	fmt.Println(gfile.GetContents(tempFile))

	// Output:
	// goframe example content
}

PutContentsAppend

• 说明：追加字符串内容到指定文件，如果文件不存在将会递归的形式自动创建。
• 格式: 

func PutContentsAppend(path string, content string) error

• 示例：

func ExamplePutContentsAppend() {
	// init
	var (
		fileName = "gflie_example.txt"
		tempDir  = gfile.TempDir("gfile_example_content")
		tempFile = gfile.Join(tempDir, fileName)
	)

	// write contents
	gfile.PutContents(tempFile, "goframe example content")

	// read contents
	fmt.Println(gfile.GetContents(tempFile))

	// It creates and append content string into specifies file path.
	// It automatically creates directory recursively if it does not exist.
	gfile.PutContentsAppend(tempFile, " append content")

	// read contents
	fmt.Println(gfile.GetContents(tempFile))

	// Output:
	// goframe example content
	// goframe example content append content
}

PutBytesAppend

• 说明：追加字节内容到指定文件。如果文件不存在将会递归的形式自动创建。
• 格式: 

func PutBytesAppend(path string, content []byte) error

• 示例：

func ExamplePutBytesAppend() {
	// init
	var (
		fileName = "gflie_example.txt"
		tempDir  = gfile.TempDir("gfile_example_content")
		tempFile = gfile.Join(tempDir, fileName)
	)

	// write contents
	gfile.PutContents(tempFile, "goframe example content")

	// read contents
	fmt.Println(gfile.GetContents(tempFile))

	// write contents
	gfile.PutBytesAppend(tempFile, []byte(" append"))

	// read contents
	fmt.Println(gfile.GetContents(tempFile))

	// Output:
	// goframe example content
	// goframe example content append
}

GetNextCharOffset

• 说明：从某个偏移量开始，获取文件中指定字符所在下标
• 格式: 

func GetNextCharOffset(reader io.ReaderAt, char byte, start int64) int64

• 示例：

func ExampleGetNextCharOffset() {
	// init
	var (
		fileName = "gflie_example.txt"
		tempDir  = gfile.TempDir("gfile_example_content")
		tempFile = gfile.Join(tempDir, fileName)
	)

	// write contents
	gfile.PutContents(tempFile, "goframe example content")
	
	f, err := gfile.OpenWithFlagPerm(tempFile, os.O_RDONLY, DefaultPermOpen)
	defer f.Close()

	// read contents
	index := gfile.GetNextCharOffset(f, f, 0)
	fmt.Println(index)

	// Output:
	// 2
}

GetNextCharOffsetByPath

• 说明：从某个偏移量开始，获取文件中指定字符所在下标
• 格式: 

func GetNextCharOffsetByPath(path string, char byte, start int64) int64 

• 示例：

func ExampleGetNextCharOffsetByPath() {
	// init
	var (
		fileName = "gflie_example.txt"
		tempDir  = gfile.TempDir("gfile_example_content")
		tempFile = gfile.Join(tempDir, fileName)
	)

	// write contents
	gfile.PutContents(tempFile, "goframe example content")

	// read contents
	index := gfile.GetNextCharOffsetByPath(tempFile, f, 0)
	fmt.Println(index)

	// Output:
	// 2
}

GetBytesTilCharByPath

• 说明：以某个字符定位截取指定长度的文件内容以字节形式返回
• 格式: 

func GetBytesTilCharByPath(path string, char byte, start int64) ([]byte, int64) 

• 示例：

func ExampleGetBytesTilCharByPath() {
	// init
	var (
		fileName = "gflie_example.txt"
		tempDir  = gfile.TempDir("gfile_example_content")
		tempFile = gfile.Join(tempDir, fileName)
	)

	// write contents
	gfile.PutContents(tempFile, "goframe example content")

	// read contents
	fmt.Println(gfile.GetBytesTilCharByPath(tempFile, f, 0))

	// Output:
	// [103 111 102] 2
}

GetBytesByTwoOffsetsByPath

• 说明：用两个偏移量截取指定文件的内容以字节形式返回
• 格式: 

func GetBytesByTwoOffsetsByPath(path string, start int64, end int64) []byte

• 示例：

func ExampleGetBytesByTwoOffsetsByPath() {
	// init
	var (
		fileName = "gflie_example.txt"
		tempDir  = gfile.TempDir("gfile_example_content")
		tempFile = gfile.Join(tempDir, fileName)
	)

	// write contents
	gfile.PutContents(tempFile, "goframe example content")

	// read contents
	fmt.Println(gfile.GetBytesByTwoOffsetsByPath(tempFile, 0, 7))

	// Output:
	// [103 111 102 114 97 109 101]
}

ReadLines

• 说明：以字符串形式逐行读取文件内容
• 格式: 

func ReadLines(file string, callback func(text string) error) error

• 示例：

func ExampleReadLines() {
	// init
	var (
		fileName = "gflie_example.txt"
		tempDir  = gfile.TempDir("gfile_example_content")
		tempFile = gfile.Join(tempDir, fileName)
	)

	// write contents
	gfile.PutContents(tempFile, "L1 goframe example content
L2 goframe example content")

	// read contents
	gfile.ReadLines(tempFile, func(text string) error {
		// Process each line
		fmt.Println(text)
		return nil
	})

	// Output:
	// L1 goframe example content
	// L2 goframe example content
}

ReadLinesBytes

• 说明：以字节形式逐行读取文件内容
• 格式:

func ReadLinesBytes(file string, callback func(bytes []byte) error) error 

• 示例：

func ExampleReadLinesBytes() {
	// init
	var (
		fileName = "gflie_example.txt"
		tempDir  = gfile.TempDir("gfile_example_content")
		tempFile = gfile.Join(tempDir, fileName)
	)

	// write contents
	gfile.PutContents(tempFile, "L1 goframe example content
L2 goframe example content")

	// read contents
	gfile.ReadLinesBytes(tempFile, func(bytes []byte) error {
		// Process each line
		fmt.Println(bytes)
		return nil
	})

	// Output:
	// [76 49 32 103 111 102 114 97 109 101 32 101 120 97 109 112 108 101 32 99 111 110 116 101 110 116]
	// [76 50 32 103 111 102 114 97 109 101 32 101 120 97 109 112 108 101 32 99 111 110 116 101 110 116]
}

Truncate

• 说明：裁剪文件为指定大小
• 注意：如果给定文件路径是软链，将会修改源文件
• 格式: 

func Truncate(path string, size int) error

• 示例：

func ExampleTruncate(){
	// init
	var (
		path = gfile.Join(gfile.TempDir("gfile_example_basic_dir"), "file1")
	)

	// Check whether the `path` size
	stat, _ := gfile.Stat(path)
	fmt.Println(stat.Size())

	// Truncate file
	gfile.Truncate(path, 0)

	// Check whether the `path` size
	stat, _ = gfile.Stat(path)
	fmt.Println(stat.Size())

	// Output:
	// 13
	// 0
}