# Read a VTK from a file content
**URL:** https://discourse.vtk.org/t/read-a-vtk-from-a-file-content/9017
**Category:** Support
**Tags:** python, code, file-formats
**Created:** [July 26, 2022, 5:39am UTC](https://discourse.vtk.org/t/read-a-vtk-from-a-file-content/9017 "2022-07-26T05:39:21Z")
**Posts on this page:** 6
**Page:** 1
### Author:  [@moshec](https://discourse.vtk.org/u/moshec)
#### Post date: [July 26, 2022, 5:39am UTC](https://discourse.vtk.org/t/read-a-vtk-from-a-file-content/9017/1 "2022-07-26T05:39:21Z")
Hi everyone,
I’m using Python,
I have a tar file that contains some VTK files,
I don’t want to extract the files to the hard disk and then read the file with a reader-
Instead, I assign the VTK file content in run time to a local variable, and I’m looking for a way to read it.
This is the method I’m using for reading directly from a VTK file and it works:
```auto
def load_vtk_to_array(path: str):
reader = vtkStructuredPointsReader()
reader.SetFileName(path)
reader.Update()
data = reader.GetOutput()
shape = data.GetDimensions()[::-1]
array = numpy_support.vtk_to_numpy(data.GetPointData().GetArray(0)).reshape(shape)
return array
```
But I want to use something like this method:
```auto
def load_vtk_to_array(file_content: bytes):
reader = vtkStructuredPointsReader()
reader.SetBinaryInputString(file_content)
reader.Update()
data = reader.GetOutput()
shape = data.GetDimensions()[::-1] ## we get (0,0,0)
array = numpy_support.vtk_to_numpy(data.GetPointData().GetArray(0)).reshape(shape)
return array
```
But this is not work here, the data does not contain GetPointData() method so it raise an exception and the Dimensions we get is (0,0,0)☹
the file headers:
```auto
# vtk DataFile Version 3.0
vtk output
BINARY
DATASET STRUCTURED_POINTS
DIMENSIONS tel:272 102 288
SPACING 1.62 1.62 2.14
ORIGIN 0 0 0
CELL_DATA tel:7855477
POINT_DATA tel:7990272
SCALARS scalars unsigned_short
LOOKUP_TABLE default
```
Thanks in advance
---
### Author:  [@ben.boeckel](https://discourse.vtk.org/u/ben.boeckel)
#### Post date: [July 26, 2022, 1:39pm UTC](https://discourse.vtk.org/t/read-a-vtk-from-a-file-content/9017/2 "2022-07-26T13:39:36Z")
> [@moshec](#):
>
> I don’t want to extract the files to the hard disk and then read the file with a reader-
> Instead, I assign the VTK file content in run time to a local variable, and I’m looking for a way to read it.
Not many readers support this mode of operation. Even if they did, there’d need to be some way to hand over a Python object as a stream to the filter via the wrappers (@dgobbi). I made one years ago with `boost::iostreams`, but I’d have to dig it up again (we’d also not want a Boost dependency there anyways).
---
### Author:  [@dgobbi](https://discourse.vtk.org/u/dgobbi)
#### Post date: [July 26, 2022, 3:08pm UTC](https://discourse.vtk.org/t/read-a-vtk-from-a-file-content/9017/3 "2022-07-26T15:08:57Z")
> [@moshec](#):
>
> the data does not contain GetPointData() method
Are you sure about this? Even if the reader fails, a `vtkStructuredPoints` data set _always_ has a `GetPointData()` method.
```plaintext
>>> reader = vtkStructuredPointsReader()
>>> data = reader.GetOutput()
>>> type(data)
>>> pd = data.GetPointData()
>>> type(pd)
```
It’s possible that `SetBinaryInputString()`/`Update()` fails because the Python wrappers encode the binary `char*` as a utf-8 encoded string instead of as binary data.
Have you tried using an ASCII data file with the `SetInputString()` method to see if that works? If an ASCII data file works but a binary data file does not work, then we will know that the `SetBinaryInputString()` method is the problem.
---
### Author:  [@toddy](https://discourse.vtk.org/u/toddy)
#### Post date: [July 27, 2022, 1:08am UTC](https://discourse.vtk.org/t/read-a-vtk-from-a-file-content/9017/4 "2022-07-27T01:08:41Z")
This doesn’t look right
```auto
void vtkDataReader::SetBinaryInputString(const char* in, int len)
{
this->SetInputString(in, len);
}
```
---
### Author:  [@dgobbi](https://discourse.vtk.org/u/dgobbi)
#### Post date: [July 27, 2022, 1:19am UTC](https://discourse.vtk.org/t/read-a-vtk-from-a-file-content/9017/5 "2022-07-27T01:19:26Z")
Since the file header provides information about whether the data is stored in text or in binary, it’s not inconceivable that `SetInputString(in,len)` and `SetBinaryInputString(in,len)` would share the same implementation.
---
### Author:  [@toddy](https://discourse.vtk.org/u/toddy)
#### Post date: [July 27, 2022, 1:53am UTC](https://discourse.vtk.org/t/read-a-vtk-from-a-file-content/9017/6 "2022-07-27T01:53:27Z")
> [@toddy](#):
>
> `void vtkDataReader::SetBinaryInputString(const char* in, int len)`
Shouldn’t this be **const unsigned char** \* so that the wrapper code doesn’t convert to utf-8?