简化了将[]字节转换为“字节”的方法;虚拟的;golang中的文件对象?
我知道有一些Go库可以创建整个文件系统,比如。但是我只想把一个字节数组制作成能够满足接口要求的东西。看起来很简单,可以自己模拟一下简化了将[]字节转换为“字节”的方法;虚拟的;golang中的文件对象?,go,virtual-file,Go,Virtual File,我知道有一些Go库可以创建整个文件系统,比如。但是我只想把一个字节数组制作成能够满足接口要求的东西。看起来很简单,可以自己模拟一下 type MockFile struct { data []byte isOpen bool offset int64 } type MockFileInfo struct { mockFile *MockFile } func (mfi *MockFileInfo) Name() string { retur
type MockFile struct {
data []byte
isOpen bool
offset int64
}
type MockFileInfo struct {
mockFile *MockFile
}
func (mfi *MockFileInfo) Name() string { return "MockFile" }
func (mfi *MockFileInfo) Size() int64 { return len(mfi.data) }
func (mfi *MockFileInfo) Mode() os.FileMode { return os.ModeIrregular }
func (mfi *MockFileInfo) ModTime() time.Time { return time.Now() }
func (mfi *MockFileInfo) IsDir() bool { return false }
func (mfi *MockFileInfo) Sys() interface { return nil }
func (mf *MockFile) Read(p []byte) (n int, err error) {
if mf.isOpen {
n = copy(p, mf.data[mf.offset:])
mf.offset += n
} else {
err = errors.New("Cannot read from closed MockFile")
}
return
}
func (mf *MockFile) Close() error {
if !mf.isOpen {
return errors.New("Cannot close an already closed MockFile")
mf.isOpen = false
return nil
}
func (mf *MockFile) Seek(offset int64, whence int) (ret int64, err error) {
var relativeTo int64
switch whence {
case 0:
relativeTo = 0
case 1:
relativeTo = mf.offset
case 2:
relativeTo = len(mf.data)
}
ret := relativeTo + offset
if ret < 0 || ret > len(mf.data) {
return -1, errors.New("New offset would fall outside of the MockFile")
}
mf.offset = ret
return
}
func (mf *MockFile) Readdir(count int) ([]os.FileInfo, error) {
if count <= 0 {
return []os.FileInfo{}, nil
}
return []os.FileInfo{}, errors.New("MockFiles have no associated directory")
}
func (mf *MockFile) Stat() (os.FileInfo, error) {
return MockFileInfo{mf}
}
func OpenMockFile(data []byte) *MockFile {
mf := MockFile{data, true, 0}
}
键入MockFile结构{
数据[]字节
等温布尔
偏移量int64
}
输入MockFileInfo结构{
mockFile*mockFile
}
func(mfi*MockFileInfo)Name()字符串{返回“MockFile”}
func(mfi*MockFileInfo)Size()int64{return len(mfi.data)}
func(mfi*MockFileInfo)Mode()os.FileMode{return os.Mode}
func(mfi*MockFileInfo)ModTime()time.time{return time.Now()}
func(mfi*MockFileInfo)IsDir()bool{return false}
func(mfi*MockFileInfo)Sys()接口{return nil}
func(mf*MockFile)读取(p[]字节)(n int,err error){
如果mf.isOpen{
n=复制(p,mf.data[mf.offset:])
mf.offset+=n
}否则{
err=errors.New(“无法从关闭的模拟文件中读取”)
}
返回
}
func(mf*MockFile)Close()错误{
如果!伊索彭小姐{
返回错误。新建(“无法关闭已关闭的文件”)
mf.isOpen=false
归零
}
func(mf*MockFile)Seek(偏移量int64,whence int)(ret int64,err error){
与int64相关的var
开关从哪里来{
案例0:
相对论=0
案例1:
相对偏差=mf.offset
案例2:
relativeTo=len(mf.数据)
}
ret:=相对值+偏移量
如果ret<0 | | ret>len(mf.数据){
return-1,errors.New(“新偏移量将落在MockFile之外”)
}
mf.offset=ret
返回
}
func(mf*MockFile)Readdir(count int)([]os.FileInfo,错误){
如果count在标准库中没有现成的解决方案,但是自己动手并不难
type MockFile struct {
data []byte
isOpen bool
offset int64
}
type MockFileInfo struct {
mockFile *MockFile
}
func (mfi *MockFileInfo) Name() string { return "MockFile" }
func (mfi *MockFileInfo) Size() int64 { return len(mfi.data) }
func (mfi *MockFileInfo) Mode() os.FileMode { return os.ModeIrregular }
func (mfi *MockFileInfo) ModTime() time.Time { return time.Now() }
func (mfi *MockFileInfo) IsDir() bool { return false }
func (mfi *MockFileInfo) Sys() interface { return nil }
func (mf *MockFile) Read(p []byte) (n int, err error) {
if mf.isOpen {
n = copy(p, mf.data[mf.offset:])
mf.offset += n
} else {
err = errors.New("Cannot read from closed MockFile")
}
return
}
func (mf *MockFile) Close() error {
if !mf.isOpen {
return errors.New("Cannot close an already closed MockFile")
mf.isOpen = false
return nil
}
func (mf *MockFile) Seek(offset int64, whence int) (ret int64, err error) {
var relativeTo int64
switch whence {
case 0:
relativeTo = 0
case 1:
relativeTo = mf.offset
case 2:
relativeTo = len(mf.data)
}
ret := relativeTo + offset
if ret < 0 || ret > len(mf.data) {
return -1, errors.New("New offset would fall outside of the MockFile")
}
mf.offset = ret
return
}
func (mf *MockFile) Readdir(count int) ([]os.FileInfo, error) {
if count <= 0 {
return []os.FileInfo{}, nil
}
return []os.FileInfo{}, errors.New("MockFiles have no associated directory")
}
func (mf *MockFile) Stat() (os.FileInfo, error) {
return MockFileInfo{mf}
}
func OpenMockFile(data []byte) *MockFile {
mf := MockFile{data, true, 0}
}
我们需要的是这个接口:
type File interface {
io.Closer
io.Reader
io.Seeker
Readdir(count int) ([]os.FileInfo, error)
Stat() (os.FileInfo, error)
}
请注意,我们可以利用它来完成这项繁重的任务,因为只有它才能实现和。可以是noop,Readdir()
可能返回nil,nil
,因为我们模拟的是文件而不是目录,它的Readdir()
甚至不会被调用
“最难”的部分是模拟Stat()
以返回实现的值
下面是一个简单的模拟FileInfo
:
type myFileInfo struct {
name string
data []byte
}
func (mif myFileInfo) Name() string { return mif.name }
func (mif myFileInfo) Size() int64 { return int64(len(mif.data)) }
func (mif myFileInfo) Mode() os.FileMode { return 0444 } // Read for all
func (mif myFileInfo) ModTime() time.Time { return time.Time{} } // Return anything
func (mif myFileInfo) IsDir() bool { return false }
func (mif myFileInfo) Sys() interface{} { return nil }
有了这些,我们就可以创建我们的模拟http.File
:
type MyFile struct {
*bytes.Reader
mif myFileInfo
}
func (mf *MyFile) Close() error { return nil } // Noop, nothing to do
func (mf *MyFile) Readdir(count int) ([]os.FileInfo, error) {
return nil, nil // We are not a directory but a single file
}
func (mf *MyFile) Stat() (os.FileInfo, error) {
return mf.mif, nil
}
使用它的示例(在上尝试):
如果您正在寻找gzip http2推送的这个答案,您可以使用以下选项:
options := &http.PushOptions{
Header: http.Header{
"Accept-Encoding": r.Header["Accept-Encoding"],
},
}
if err := pusher.Push(filePush, options); err != nil {
log.Printf("Failed to push: %v", err)
return
}
你真的必须模拟整个文件吗?我不确定一个字节片在逻辑上如何实现Readdir
(除了[]os.FileInfo{},someErr
)诚然,我不确定MockFile.Stat()
完全符合它的期望。可能MockFileInfo
应该使用MockFile
而不是*MockFile
。如果你os.Stat
一个真实的文件,然后改变它的大小,会发生什么?文件大小的变化是否反映在os.FileInfo
中?