# Read gzipped protobuf file

**URL:** <https://discourse.julialang.org/t/read-gzipped-protobuf-file/50215>\
**Category:** General Usage\
**Created:** [November 16, 2020, 7:08am UTC](https://discourse.julialang.org/t/read-gzipped-protobuf-file/50215 "2020-11-16T07:08:13Z")\
**Posts on this page:** 2\
**Page:** 1

<div class="post-metadata">

**Author:** ![unis](https://sea2.discourse-cdn.com/julialang/user_avatar/discourse.julialang.org/unis/32/19458_2.png) [@unis](https://discourse.julialang.org/u/unis)\
**Post date:** [November 16, 2020, 7:08am UTC](https://discourse.julialang.org/t/read-gzipped-protobuf-file/50215/1 "2020-11-16T07:08:13Z")

</div>

I have a “protobuf reader”, generated using protoc, `proto/coordinate_push.jl`, using which I’d like to import a gzipped file. This file contains a list of frames, each containing object coordinates.

The corresponding Python code, which I try to migrate, is:

```
frameList = []

with gzip.open(filePath) as f:
	data = f.read()
	next_pos, pos = 0, 0

	while pos < len(data):
		msg = coordinate_push.CoordinatesFrame()

		next_pos, pos = _DecodeVarint32(data, pos)
		msg.ParseFromString(data[pos:pos + next_pos])

		frameList.append(msg)

		pos += next_pos

```

Being new to Julia and generally not strong at IO (also in Python), I’m unsure how to to start. The following code yields an `ERROR: LoadError: UndefVarError: load not defined`.

```
 include("proto/coordinate_push.jl")
 using FileIO
 using ProtoBuf
 file_path = "sensor_1502063868355_1502064000053.dat.gz" #example
 obj = load(file_path) #I have also tried explicitly FileIO.load()
 readproto(obj, CoordinatesFrame())

```

In some more detail, the error reads as

```
 [1] handle_error(::UndefVarError, ::File{DataFormat{:GZIP}}) at C:\Users\unis\.juliapro\JuliaPro_v1.4.2-1\packages\FileIO\zL0JE\src\error_handling.jl:82
 [2] handle_exceptions(::Array{Any,1}, ::String) at C:\Users\unis\.juliapro\JuliaPro_v1.4.2-1\packages\FileIO\zL0JE\src\error_handling.jl:77

```

I had initially asked this question on [StackOverflow](https://stackoverflow.com/questions/64822972/julia-using-protobuf-to-read-messages-from-gzipped-file/64840533#64840533). I’m using Julia 1.4.2 (which I could update if needed) on Windows (latest version).

My guess is that somehow FileIO.load() can’t deal with gzipped files. I would highly appreciate any comments or hints that help migrating the above Python code (including also the replication of the while loop, if possible). Thank you!

---

<div class="post-metadata">

**Author:** ![GunnarFarneback](https://sea2.discourse-cdn.com/julialang/user_avatar/discourse.julialang.org/gunnarfarneback/32/1827_2.png) [@GunnarFarneback](https://discourse.julialang.org/u/GunnarFarneback)\
**Post date:** [November 16, 2020, 7:22am UTC](https://discourse.julialang.org/t/read-gzipped-protobuf-file/50215/2 "2020-11-16T07:22:54Z")

</div>

For the gzip reading part you want to look into [https://github.com/JuliaIO/CodecZlib.jl](https://github.com/JuliaIO/CodecZlib.jl).