标准库中没有现成的解决方案,但是自己做起来并不难。
我们需要这个http.File
接口:
type File interface {
io.Closer
io.Reader
io.Seeker
Readdir(count int) ([]os.FileInfo, error)
Stat() (os.FileInfo, error)
}
bytes.Reader
来完成繁重的任务,因为它本身实现了 io.Reader
和 io.Seeker
。 io.Closer
可以是一个空操作,而 Readdir()
可能会返回 nil, nil
,因为我们模拟的是文件而不是目录,其 Readdir()
甚至不会被调用。Stat()
以返回实现了 os.FileInfo
的值。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 }
那么现在我们拥有了一切来创建我们的模拟 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
}
以下是使用it的示例(在Go Playground上尝试):
data := []byte{0, 1, 2, 3}
mf := &MyFile{
Reader: bytes.NewReader(data),
mif: myFileInfo{
name: "somename.txt",
data: data,
},
}
var f http.File = mf
_ = f
看起来很简单,你可以自己模拟。
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}
}
MockFile.Stat()
是否完全符合预期。也许MockFileInfo
应该采用MockFile
而非*MockFile
。如果您对真实文件执行os.Stat
,然后更改其大小会发生什么?文件大小的更改是否会反映在os.FileInfo
中? - Adam Smithoptions := &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
}
Readdir
(除了[]os.FileInfo {},someErr
)。 - Adam Smith